Substituted pyrazolo[1,5-A]pyridine compounds as RET kinase inhibitors

This application is a continuation of U.S. application Ser. No. 15/211,702, filed Jul. 15, 2016, which claims priority to U.S. Provisional Application Ser. No. 62/193,448, filed Jul. 16, 2015 and 62/274,018, filed Dec. 31, 2015, both of which are hereby incorporated by reference in their entireties.

The present disclosure relates to novel compounds which exhibit Rearranged during Transfection (RET) kinase inhibition, pharmaceutical compositions comprising the compounds, processes for making the compounds, and the use of the compounds in therapy. More particularly, it relates to substituted pyrazolo[1,5-a]pyridine compounds useful in the treatment and prevention of diseases which can be treated with a RET kinase inhibitor, including RET-associated diseases and disorders.

RET is a single-pass transmembrane receptor belonging to the tyrosine kinase superfamily that is required for normal development, maturation and maintenance of several tissues and cell types (Mulligan, L. M., Nature Reviews Cancer, 2014, 14, 173-186). The extracellular portion of the RET kinase contains four calcium-dependent cadherin-like repeats involved in ligand binding and a juxtamembrane cysteine-rich region necessary for the correct folding of the RET extracellular domain, while the cytoplasmic portion of the receptor includes two tyrosine kinase subdomains.

RET signaling is mediated by the binding of a group of soluble proteins of the glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs), which also includes neurturin (NTRN), artemin (ARTN) and persephin (PSPN) (Arighi et al., Cytokine Growth Factor Rev., 2005, 16, 441-67). Unlike other receptor tyrosine kinases, RET does not directly bind to GFLs and requires an additional co-receptor: that is, one of four GDNF family receptor-α (GFRα) family members, which are tethered to the cell surface by a glycosylphosphatidylinositol linkage. GFLs and GFRa family members form binary complexes that in turn bind to RET and recruit it into cholesterol-rich membrane subdomains, which are known as lipid rafts, where RET signaling occurs.

Upon binding of the ligand-co-receptor complex, RET dimerization and autophosphorylation on intracellular tyrosine residues recruits adaptor and signaling proteins to stimulate multiple downstream pathways. Adaptor protein binding to these docking sites leads to activation of Ras-MAPK and PI3K-Akt/mTOR signaling pathways or to recruitment of the CBL family of ubiquitin ligases that functions in RET downregulation of the RET-mediated functions.

Aberrant RET expression and/or activity have been demonstrated in different cancers and in gastrointestinal disorders such as irritable bowel syndrome (IBS).

It has now been found that substituted pyrazolo[1,5-a]pyridine compounds are inhibitors of RET kinase, and are useful for treating diseases such as proliferative diseases including cancers.

Accordingly, provided herein is a compound of the General Formula I:

or a pharmaceutically acceptable salt or solvate thereof, wherein A, B, D, E, X 1 , X 2 , X 3 and X 4 are as defined herein.

Also provided herein is a pharmaceutical composition comprising a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, in admixture with a pharmaceutically acceptable diluent or carrier.

Also provided herein is a method of inhibiting cell proliferation, in vitro or in vivo, the method comprising contacting a cell with an effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition thereof as defined herein.

Also provided herein is a method of treating a RET-associated disease or disorder in a patient in need of such treatment, the method comprising administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition thereof as defined herein.

Also provided herein is a method of treating cancer and/or inhibiting metastasis associated with a particular cancer in a patient in need of such treatment, the method comprising administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof as defined herein.

Also provided herein is a method of treating irritable bowel syndrome (IBS) and/or pain associated with IBS in a patient in need of such treatment, the method comprising administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof as defined herein.

Also provided is a method of providing supportive care to a cancer patient, including preventing or minimizing gastrointestinal disorders, such as diarrhea, associated with treatment, including chemotherapeutic treatment, the method comprising administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof as defined herein.

Also provided herein is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition thereof as defined herein for use in therapy.

Also provided herein is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof as defined herein for use in the treatment of cancer and/or inhibiting metastasis associated with a particular cancer.

Also provided herein is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof as defined herein for use in the treatment of irritable bowel syndrome (IBS) or pain associated with IBS.

Also provided is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof as defined herein for use providing supportive care to a cancer patient, including preventing or minimizing gastrointestinal disorders, such as diarrhea, associated with treatment, including chemotherapeutic treatment.

Also provided herein is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof for use in the inhibition of RET kinase activity.

Also provided herein is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof as defined herein, for use in the treatment of a RET-associated disease or disorder.

Also provided herein is the use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as defined herein in the manufacture of a medicament for the treatment of cancer and/or inhibiting metastasis associated with a particular cancer.

Also provided herein is the use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as defined herein in the manufacture of a medicament for the treatment of irritable bowel syndrome (IBS) or pain associated with IBS.

Also provided herein is the use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as defined herein in the manufacture of a medicament for providing supportive care to a cancer patient, including preventing or minimizing gastrointestinal disorders, such as diarrhea, associated with treatment, including chemotherapeutic treatment.

Also provided herein is a use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as defined herein in the manufacture of a medicament for the inhibition of RET kinase activity.

Also provided herein is the use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as defined herein, in the manufacture of a medicament for the treatment of a RET-associated disease or disorder.

Also provided herein is a method for treating cancer in a patient in need thereof, the method comprising (a) determining if the cancer is associated with a dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., a RET-associated cancer); and (b) if the cancer is determined to be associated with a dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., a RET-associated cancer), administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition thereof.

Also provided herein is a pharmaceutical combination for treating cancer (e.g., a RET-associated cancer, such as a RET-associated cancer having one or more RET inhibitor resistance mutations) in a patient in need thereof, which comprises (a) a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, (b) an additional therapeutic agent, and (c) optionally at least one pharmaceutically acceptable carrier, wherein the compound of General Formula I or the pharmaceutically acceptable salt or solvate thereof and the additional therapeutic are formulated as separate compositions or dosages for simultaneous, separate or sequential use for the treatment of cancer, wherein the amounts of the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof and of the additional therapeutic agent are together effective in treating the cancer. Also provided herein is a pharmaceutical composition comprising such a combination. Also provided herein is the use of such a combination for the preparation of a medicament for the treatment of cancer. Also provided herein is a commercial package or product comprising such a combination as a combined preparation for simultaneous, separate or sequential use; and to a method of treatment of cancer a patient in need thereof.

Also provided herein is a method for reversing or preventing acquired resistance to an anticancer drug, comprising administering a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, to a patient at risk for developing or having acquired resistance to an anticancer drug. In some embodiments, the patient is administered a dose of the anticancer drug (e.g., at substantially the same time as a dose of a compound of Formula I or a pharmaceutically acceptable salt or solvate thereof is administered to the patient).

Also provided herein is a method of delaying and/or preventing development of cancer resistant to an anticancer drug in an individual, comprising administering to the individual an effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, before, during, or after administration of an effective amount of the anticancer drug.

Also provided herein is a method of treating an individual with cancer who has an increased likelihood of developing resistance to an anticancer drug, comprising concomitantly administering to the individual (a) an effective amount of a compound of General Formula I and (b) an effective amount of the anticancer drug.

Also provided are methods of treating an individual with a RET-associated cancer that has one or more RET inhibitor resistance mutations that increase resistance of the cancer to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof (e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E), that include administering a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, before, during, or after administration of another anticancer drug (e.g., a RET kinase inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof).

Also provided are methods of treating an individual with a RET-associated cancer that include administering a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, before, during, or after administration of another anticancer drug (e.g., a RET kinase inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof).

Also provided herein is a method for treating irritable bowel syndrome (IBS) in a patient in need thereof, the method comprising (a) determining if the IBS is associated with a dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same; and (b) if the IBS is determined to be associated with a dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition thereof.

Also provided herein is a pharmaceutical combination for treating irritable bowel syndrome (IBS) in a patient in need thereof, which comprises administering (a) a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, (b) an additional therapeutic agent, and (c) optionally at least one pharmaceutically acceptable carrier, for simultaneous, separate or sequential use for the treatment of IBS, wherein the amounts of the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof and of the additional therapeutic agent are together effective in treating the IBS. Also provided herein is a pharmaceutical composition comprising such a combination. Also provided herein is the use of such a combination for the preparation of a medicament for the treatment of the IBS. Also provided herein is a commercial package or product comprising such a combination as a combined preparation for simultaneous, separate or sequential use; and to a method of treatment of the IBS a patient in need thereof.

Also provided herein is a process for preparing a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof.

Also provided herein is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof obtained by a process of preparing the compound as defined herein.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Methods and materials are described herein for use in the present invention; other, suitable methods and materials known in the art can also be used. The materials, methods, and examples are illustrative only and not intended to be limiting. All publications, patent applications, patents, sequences, database entries, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

Other features and advantages of the invention will be apparent from the following detailed description and figures, and from the claims.

Provided herein is a compound of the General Formula I:

or a pharmaceutically acceptable salt or solvate thereof, wherein:

X 1 is CH, CCH 3 , CF, CCl or N;

X 2 is CH, CF or N;

X 3 is CH, CF or N;

X 4 is CH, CF or N;

wherein zero, one or two of X 1 , X 2 , X 3 and X 4 is N;

A is H, Cl, CN, Br, CH 3 , CH 2 CH 3 or cyclopropyl;

B is hetAr 1 ;

hetAr 1 is a 5-membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, S and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, hydroxyC1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, cyanoC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, (C1-C4 alkoxy)CH 2 C(═O)—, (C1-C4 alkoxy)C(═O)C1-C3 alkyl, C3-C6 cycloalkyl, (R a R b N)C1-C6 alkyl, (R a R b N)C(═O)C1-C6 alkyl, (C1-C6 alkyl SO 2 )C1-C6 alkyl, hetCyc a and 4-methoxybenzyl;

R a and R b are independently H or C1-C6 alkyl;

hetCyc a is a 4-6 membered heterocyclic ring having a ring heteroatom selected from N and O, wherein the heterocyclic ring is optionally substituted with halogen, C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, di(C1-C3 alkyl)NCH 2 C(═O), (C1-C6 alkoxy)C(═O) or (C1-C6 alkoxy)CH 2 C(═O);

D is hetCyc a , hetCyc 2 , hetCyc 3 or hetCyc 9 ;

hetCyc a is a 4-6 membered heterocyclic ring having 1-2 ring atoms selected from N and O, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl, trifluoroC1-C3 alkyl and OH, or said heterocyclic ring is substituted with a C3-C6 cycloalkylidene ring, or said heterocyclic ring is substituted with an oxo group;

hetCyc 2 is a 7-8 membered bridged heterocyclic ring having 1-3 ring heteroatoms independently selected from N and O, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl;

hetCyc 3 is a 7-11 membered heterospirocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the ring is optionally substituted with C1-C3 alkyl;

hetCyc 9 is a fused 9-10 membered heterocyclic ring having 1-3 ring nitrogen atoms and optionally substituted with oxo;

E is

(a) hydrogen,

(b) OH,

(c) R a R b N—, wherein R a is H or C1-C6 alkyl and R b is H, C1-C6 alkyl or phenyl;

(d) C1-C6 alkyl optionally substituted with one to three fluoros,

(e) hydroxyC1-C6 alkyl- optionally substituted with one to three fluoros,

(f) C1-C6 alkoxy optionally substituted with one to three fluoros,

(g) hydroxy(C1-C6 alkoxy) optionally substituted with one to three fluoros,

(h) (C1-C6 alkoxy)hydroxy C1-C6 alkyl- optionally substituted with one to three fluoros,

(i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros,

(j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros,

(k) (C1-C6 alkoxy)C(═O)—,

(l) (C1-C6 alkoxy)(C1-C6 alkyl)C(═O)—,

(m) HC(═O)—,

(n) Cyc 1 ,

(o) Cyc 1 C(═O)—,

(p) Cyc 1 (C1-C6 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or more groups independently selected from the group consisting of OH, fluoro, C1-C3 alkoxy and R c R d N—, where R c and R d are independently H or C1-C6 alkyl,

(q) hetCyc 4 ,

(r) hetCyc 4 C(═O)—,

(s) hetCyc 4 (C1-C3 alkyl)C(═O)—,

(t) (hetCyc 4 )C(═O)C1-C2 alkyl-,

(u) hetCyc 4 C(═O)NH—,

(v) Ar 2 ,

(w) Ar 2 C(═O)—,

(x) Ar 2 C1-C6 alkyl-,

(y) (Ar 2 )hydroxy C2-C6 alkyl-,

(z) Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O,

(aa) hetAr 2 C(═O)—,

(bb) (hetAr 2 )hydroxyC2-C6 alkyl-,

(cc) hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O,

(dd) R 1 R 2 NC(═O)—,

(ee) R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with phenyl,

(ff) R 1 R 2 NC(═O)C1-C2 alkyl-,

(gg) R 1 R 2 NC(═O)NH—,

(hh) CH 3 SO 2 (C1-C6 alkyl)C(═O)—,

(ii) (C1-C6 alkyl)SO 2 —,

(jj) (C3-C6 cycloalkyl)CH 2 SO 2 —,

(kk) hetCyc 5 -SO 2 —,

(ll) R 4 R 5 NSO 2 —,

(mm) R 6 C(═O)NH—,

(nn) hetCyc 6 ;

(oo) hetAr 2 C1-C6 alkyl-,

(pp) (hetCyc 4 )C1-C6 alkyl-,

(qq) (C1-C6 alkoxy)C1-C6 alkyl- wherein said alkoxy portion is optionally substituted with 1-3 fluoros,

(rr) (C3-C6 cycloalkoxy)C1-C6 alkyl-,

(ss) (C3-C6 cycloalkyl)C1-C6 alkyl- wherein said cycloalkyl is optionally substituted with 1-2 fluoros,

(tt) (R g R h N)C1-C6 alkyl- wherein R g and R h are independently H or C1-C6 alkyl,

(uu) Ar 2 —O—,

(vv) (C1-C6 alkylSO 2 )C1-C6 alkyl-,

(ww) (C1-C6 alkoxy)C(═O)NHC1-C6 alkyl-,

(xx) (C3-C6 cycloalkoxy)C(═O)—,

(yy) (C3-C6 cycloalkyl)SO 2 — wherein said cycloalkyl is optionally substituted with C1-C6 alkyl,

(zz) Ar 4 CH 2 OC(═O)—,

(aaa) (N—(C1-C3 alkyl)pyridinonyl)C1-C3 alkyl-, and

(bbb) (Ar 4 SO 2 )C1-C6 alkyl-;

Cyc 1 is a C3-C6 cycloalkyl, wherein (a) the cycloalkyl is optionally substituted with one or more substituents independently selected from the group consisting of OH, halogen, C1-C6 alkoxy, CN, hydroxyC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, and C1-C6 alkyl optionally substituted with 1-3 fluoros, or (b) the cycloalkyl is substituted with phenyl, wherein the phenyl is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy and CF, or (c) the cycloalkyl is substituted with a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy and CF 3 ;

Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, CN, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and R i R j N— where R i and R j are independently H and C1-C6 alkyl;

hetAr 2 is a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, O and S and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, hydroxyC1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkoxy)C1-C6 alkyl, CN and R′R″N— where R′ and R″ are independently H or C1-C3 alkyl;

hetCyc 4 is (a) a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N, O and S wherein said S is optionally oxidized to SO 2 , (b) a 7-8 membered bridged heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, (c) a 6-12 membered fused bicyclic heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O and optionally independently substituted with 1-2 C1-C6 alkyl substitutents, or (d) a 7-10 membered spirocyclic heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein each of the heterocyclic rings is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkyl)C(═O)—, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl wherein said phenyl is optionally substituted with one or more substituents selected from halogen, C1-C6 alkyl and C1-C6 alkoxy;

hetCyc 5 is a 5-6 membered heterocyclic ring having a ring heteroatom selected from O and N;

hetCyc 6 is a 5 membered heterocyclic ring having one or two ring heteroatoms independently selected from N and O, wherein the ring substituted with oxo and wherein the ring is further optionally substituted with one or more substituents independently selected from the group consisting of OH and C1-C6 alkyl;

R 1 is H, C1-C6 alkyl or (C1-C6 alkoxy)C1-C6 alkyl;

R 2 is H, C1-C6 alkyl (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C1-C6 alkyl (optionally substituted with 1-3 fluoros), Cyc 3 , hydroxyC1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C(═O), hetCyc 7 , Ar 3 , Ar 3 C1-C3 alkyl-, hydroxyC1-C6 alkoxy or (C3-C6 cycloalkyl)CH 2 O—;

Cyc 3 is a 3-6 membered carbocyclic ring optionally substituted with 1-2 groups independently selected from the group consisting of C1-C6 alkoxy, OH and halogen;

hetCyc 7 is a 5-6 membered heterocyclic ring having a ring heteroatom selected from O and N wherein the ring is optionally substituted with C1-C6 alkyl;

Ar 3 is phenyl optionally substituted with one or more substituents independently selected from halogen, C1-C3 alkyl, C1-C3 alkoxy, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl and trifluoroC1-C3 alkyl;

R 4 and R 5 are independently H or C1-C6 alkyl;

R 6 is C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, phenyl or hetCyc 8 ;

hetCyc 8 is a 5-6 membered heterocyclic ring having a ring heteroatom selected from O and N, wherein the heterocyclic ring is optionally substituted with C1-C6 alkyl; and

Ar 4 is phenyl optionally substituted with one or more halogens.

As used herein, the word “a” before a noun represents one or more of the particular noun. For example, the phrase “a cell” represents “one or more cells.”

For complex chemical names employed herein, a substituent group is typically named before the group to which it attaches. For example, methoxyethyl group comprises an ethyl backbone with a methoxy substituent.

The term “halogen” means —F (sometimes referred to herein as “fluoro” or “fluoros”), —Cl, —Br and —I.

The term “azacyclic ring” as used herein refers to a saturated heterocyclic ring having a ring nitrogen atom.

The terms “C1-C3 alkyl” and “C1-C6 alkyl” as used herein refer to saturated linear or branched-chain monovalent hydrocarbon radicals of one to three or one to six carbon atoms, respectively. Examples include, but are not limited to, methyl, ethyl, 1-propyl, isopropyl, 1-butyl, isobutyl, sec-butyl, tert-butyl, 2-methyl-2-propyl, pentyl, and hexyl.

The terms “C1-C3 alkoxy”, “C1-C4 alkoxy” and “C1-C6 alkoxy”, as used herein refer to saturated linear or branched-chain monovalent alkoxy radicals of one to three, one to four or one to six carbon atoms, respectively, wherein the radical is on the oxygen atom. Examples include methoxy, ethoxy, propoxy, isopropoxy, and butoxy.

The term “fluoroC1-C6 alkyl” as use herein refers to saturated linear or branched-chain monovalent radicals of one to six carbon atoms, wherein one of the hydrogen atoms is replaced by fluorine. Examples include fluoromethyl, 3-fluoropropyl and 2-fluoroethyl.

The term “difluoroC1-C6 alkyl” as use herein refers to saturated linear or branched-chain monovalent radicals of one to six carbon atoms, wherein two of the hydrogen atoms are replaced by fluorine. Examples include difluoromethyl, 2,2-difluoroethyl, and 1,3-difluoroprop-2-yl,

The term “trifluoroC1-C6 alkyl” as used herein refers to saturated linear or branched-chain monovalent radicals of one to six carbon atoms, wherein three of the hydrogen atoms are replaced by fluorine. Examples include trifluoromethyl, 2,2,2-trifluoroethyl, and 3,3,3-trifluoropropyl.

The term “(C1-C6 alkoxy)C1-C6 alkyl” as used herein refers to saturated linear or branched-chain monovalent radicals of one to six carbon atoms, wherein one of the carbon atoms is substituted with a (C1-C6 alkoxy) group as defined herein. Examples include methoxymethyl (CH 3 OCH 2 —) and methoxyethyl (CH 3 OCH 2 CH 2 —).

The term “hydroxyC1-C6 alkyl” as used herein refers to saturated linear or branched-chain monovalent alkyl radicals of one to six carbon atoms, wherein one of the carbon atoms is substituted with a hydroxy group.

The term “hydroxyC1-C6 alkoxy” as used herein refers to saturated linear or branched-chain monovalent alkoxy radicals of one to six carbon atoms, wherein one of the carbon atoms is substituted with a hydroxy group.

The term “(C1-C6 alkoxy)hydroxyC1-C6 alkyl” as used herein refers to a hydroxy (C1-C6 alkyl) radical as defined herein, wherein one of the carbon atoms is substituted with a C1-C6 alkoxy group as defined herein.

The term “Cyc 1 (C1-C6 alkyl)” as used herein refers to saturated linear or branched-chain monovalent alkyl radicals of one to six carbon atoms, wherein one of the carbon atoms is substituted with a 3-6 membered cycloalkyl ring.

The term “Cyc 1 (C1-C6 alkyl)C(═O)—” as used herein refers to a (C1-C6 alkyl)C(═O)— group, wherein the C1-C6 alkyl is a saturated linear or branched-chain monovalent radical of one to six carbon atoms and wherein one of the carbon atoms of the C1-C6 alkyl portion is substituted with a C3-C6 cycloalkyl group.

The term “Ar 2 C1-C6 alkyl” as used herein refers to C1-C6 alkyl radical as defined herein one of the carbon atoms of the alkyl portion is substituted with Ar 2 .

The term “(Ar 2 )hydroxy C2-C6 alkyl” as used herein refers to a hydroxyC1-C6 alkyl radical as defined herein wherein one of the carbon atoms of the alkyl portion is substituted with Ar 2 .

The term “Ar 2 (C1-C3 alkyl)C(═O)—” as used herein refers to a C1-C3 alkyl(C═O)— radical wherein the C1-C3 alkyl portion is a saturated linear or branched-chain monovalent alkyl radicals of one to three carbon atoms, wherein one of the carbon atoms is substituted with Ar 2 .

The term “(hetAr 2 )hydroxy C2-C6 alkyl” as used herein refers to a hydroxyC1-C6 alkyl radical as defined herein wherein one of the carbon atoms is substituted with hetAr 2 .

The term “hetAr 2 (C1-C3 alkyl)C(═O)—” as used herein refers to a C1-C3 alkyl(C═O)— radical wherein the C1-C3 alkyl portion is a saturated linear or branched-chain monovalent alkyl radical of one to three carbon atoms, wherein one of the carbon atoms is substituted with hetAr 2 .

The term “R 1 R 2 NC(═O)C1-C2 alkyl” as used herein refers to a C1-C2 alkyl radical wherein one of the carbon atoms is substituted with a R 1 R 2 NC(═O)— group.

The term “R 1 R 2 N(C1-C3 alkyl)C(═O)—” as used herein refers to a C1-C3 alkyl(C═O)— radical wherein the C1-C3 alkyl portion is a saturated linear or branched-chain monovalent alkyl radicals of one to three carbon atoms, wherein one of the carbon atoms is substituted with a R 1 R 2 N— group, wherein R 1 and R 2 are as defined for General Formula I.

The term “(C1-C6 alkylSO 2 )C1-C6 alkyl” as used herein as used herein refers to saturated linear or branched-chain monovalent radicals of one to six carbon atoms, wherein one of the carbon atoms is substituted with a (C1-C6 alkyl)SO 2 — group (e.g., a (CH 3 ) 2 CH 2 SO 2 — group).

The term “(Ar 4 SO 2 )C1-C6 alkyl” as used herein as used herein refers to saturated linear or branched-chain monovalent radicals of one to six carbon atoms, wherein one of the carbon atoms is substituted with a (Ar 4 )SO 2 — group.

The term “bridged heterocyclic ring” as used herein refers to a bicyclic heterocycle, wherein two common nonadjacent carbon atoms of the ring are linked by an alkylene bridge of 1, 2, 3, or 4 carbon atoms. Examples of bridged heterocyclic ring systems include 3,6-diazabicyclo[3.1.1]heptane, 2,5-diazabicyclo[2.2.1]heptane, 3,8-diazabicyclo[3.2.1]octane, 3,8-diazabicyclo[3.2.1]octane, 8-azabicyclo[3.2.1]octane and 7-azabicyclo[2.2.1]heptane.

The term “spirocyclic ring” as used herein refers to a group having two rings joined by a spirocyclic linkage through a common single carbon atom, wherein each ring is a 4-7-membered ring (including the common carbon atom).

The term “heterospirocyclic” as used herein refers to a group having two rings joined by a spirocyclic linkage through a carbon atom, wherein each ring has 4 to 6 ring atoms (with one ring atom being common to both rings), and wherein 1 or 2 of the ring atoms is a heteroatom selected from the group consisting of N and O, provided that the heteroatoms are not adjacent. Examples include 2,6-diazaspiro[3.3]heptane, 2,5-diazaspiro[3.4]octane, 2,6-diazaspiro[3.4]octane, 6-oxa-2-azaspiro[3.4]octane, 2-oxa-7-azaspiro[4.4]nonane, 7-oxa-2-azaspiro[4.5]decane, 7-oxa-2-azaspiro[3.5]nonane, 2,7-diazaspiro[3.5]nonane, 2,6-diazaspiro[3.5]nonane, 2,5-diazaspiro[3.5]nonane, 1,6-diazaspiro[3.4]octane, 1,7-diazaspiro[4.4]nonane, 2,7-diazaspiro[4.4]nonane, 2,8-diazaspiro[4.5]decane, 2,7-diazaspiro[4.5]decane, 2,6-diazaspiro[4.5]decane, 1,7-diazaspiro[3.5]nonane, 2,7-diazaspiro[3.5]nonane, 1,6-diazaspiro[3.5]nonane, 1,8-diazaspiro[4.5]decane, 2,8-diazaspiro[4.5]decane, 2,7-diazaspiro[4.5]decane, 1,7-diazaspiro[4.5]decane, 2,9-diazaspiro[5.5]undecane, and 7-azaspiro[3.5]nonane.

As used herein, the term “cycloalkylidine ring” refers to a divalent carbocyclic ring. The suffix “ylidine” refers to bivalent radical derived from a saturated hydrocarbon by removal of two hydrogen atoms from the same carbon atom.

The term “compound,” as used herein is meant to include all stereoisomers, geometric isomers, tautomers, and isotopes of the structures depicted. Compounds herein identified by name or structure as one particular tautomeric form are intended to include other tautomeric forms unless otherwise specified.

The term “tautomer” as used herein refers to compounds whose structures differ markedly in arrangement of atoms, but which exist in easy and rapid equilibrium, and it is to be understood that compounds provided herein may be depicted as different tautomers, and when compounds have tautomeric forms, all tautomeric forms are intended to be within the scope of the invention, and the naming of the compounds does not exclude any tautomer.

The term “oxo” as used herein means an oxygen that is double bonded to a carbon atom. For example, a non-limiting example of a heterocyclic ring that is substituted with an oxo group is the structure:

The term “(N—(C1-C3 alkyl)pyridinonyl)C1-C3 alkyl” as used herein refers to a C1-C3 alkyl radical as defined herein where one of the carbon atoms of the alkyl portion is substituted with a 2-oxo-1,2-dihydropyridine that is substituted on the pyridone nitrogen with 1-3 carbons. Examples include 1-methyl-1,2-dihydropyridin-2-one

In certain embodiments of Formula I, X 1 is CH, CCH 3 , CF, or CCl, X 2 is CH or CF, X 3 is CH or CF, and X 4 is CH or CF. In certain embodiments, each of X 1 , X 2 , X 3 and X 4 is CH.

In certain embodiments of Formula I, X 1 is CH, CCH 3 , CF, CCl or N, X 2 is CH, CF or N, X 3 is CH, CF or N, and X 4 is CH, CF or N, wherein one of X 1 , X 2 , X 3 and X 4 is N.

In certain embodiments of Formula I, X 1 is N, X 2 is CH or CF, X 3 is CH or CF, and X 4 is CH or CF. In certain embodiments, X 1 is N, and X 2 , X 3 and X 4 are CH.

In certain embodiments of Formula I, X 1 is CCH 3 , X 2 is CH, CF or N; X 3 is CH, CF or N, and X 4 is CH, CF or N; wherein one of X 2 , X 3 and X 4 is N. In certain embodiments, X 1 is CCH 3 , X 2 is N; X 3 is CH or CF, and X 4 is CH or CF. In certain embodiments, X 1 is CCH 3 , X 2 is N, and X 3 and X 4 are CH.

In certain embodiments of Formula I, X 1 is CH, CCH 3 , CF, CCl or N; X 2 is CH, CF or N; X 3 is CH, CF or N; and X 4 is CH, CF or N, wherein two of X 1 , X 2 , X 3 and X 4 are N.

In certain embodiments of Formula I, X 1 and X 2 are N, and X 3 and X 4 are CH or CF. In certain embodiments, X 1 and X 2 are N, and X 3 and X 4 are CH.

In certain embodiments, X 1 and X 3 are N, and X 2 and X 4 are CH or CF. In certain embodiments, X 1 and X 3 are N, and X 2 and X 4 are CH.

In certain embodiments, A is H, Cl, CN, Br, CH 3 , or CH 2 CH 3 .

In certain embodiments, A is H.

In certain embodiments, A is Cl.

In certain embodiments, A is CN.

In certain embodiments, A is Br.

In certain embodiments, A is CH 3 .

In certain embodiments, A is CH 3 CH 2 —.

In certain embodiments, A is cyclopropyl.

In certain embodiments, B is hetAr 1 where hetAr 1 is a 5-membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, S and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, hydroxyC1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, cyanoC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, (C1-C4 alkoxy)CH 2 C(═O)—, (C1-C4 alkoxy)C(═O)C1-C3 alkyl, C3-C6 cycloalkyl, (R a R b N)C1-C6 alkyl, (R a R b N)C(═)C1-C6 alkyl, (C1-C6 alkylSO 2 )C1-C6 alkyl, hetCyc a and 4-methylbenzyl.

In certain embodiments, B is hetAr 1 where hetAr 1 is a 5-membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, S and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl.

In certain embodiments, hetAr 1 is pyrazolyl, imidazolyl, oxazolyl, isoxazolyl thiazolyl, thiadiazolyl, triazolyl or oxadiazolyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, hydroxyC1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, cyanoC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, (C1-C4 alkoxy)CH 2 C(═O)—, (C1-C4 alkoxy)C(═O)C1-C3 alkyl, C3-C6 cycloalkyl, (R a R b N)C1-C6 alkyl, (R a R b N)C(═O)C1-C6 alkyl, (C1-C6 alkylSO 2 )C1-C6 alkyl, hetCyc a and 4-methoxybenzyl.

In certain embodiments, B is pyrazolyl, imidazolyl, oxazolyl or isoxazolyl optionally substituted with one or more substituents independently selected from C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, hydroxyC1-C6 alkyl, C3-C6 cycloalkyl, hetCyc a and 4-methoxybenzyl.

In certain embodiments, B is pyrazolyl or imidazolyl optionally substituted with one or more substituents independently selected from C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl.

In certain embodiments, B is pyrazolyl optionally substituted with one or more substituents independently selected from C1-C6 alkyl.

Non-limiting examples of hetAr 1 include the structures:

In certain embodiments, D is hetCyc 1 where hetCyc 1 is a 4-6 membered heterocyclic ring having 1-2 ring atoms selected from N and O, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl, trifluoroC1-C3 alkyl and OH, or the heterocyclic ring is substituted with a C3-C6 cycloalkylidene ring, or said heterocyclic ring is substituted with an oxo group.

In certain embodiments, hetCyc 1 is a pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl or azetidinyl ring optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl, trifluoroC1-C3 alkyl and OH, or hetCyc 1 is a piperazinyl ring substituted with a C3-C6 cycloalkylidene ring, or hetCyc 1 is a piperazinyl ring substituted with an oxo group.

In certain embodiments, hetCyc 1 is a pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, or azetidinyl ring optionally substituted with a group selected from C1-C3 alkyl and trifluoroC1-C3 alkyl, or the hetCyc 1 is substituted with a C3-C6 cycloalkylidene ring, or hetCyc 1 is piperazin-2-onyl. In certain embodiments, hetCyc 1 is a pyrrolidinyl, piperidinyl, piperazinyl or morpholinyl ring optionally substituted with a group selected from C1-C3 alkyl and trifluoroC1-C3 alkyl, or the hetCyc 1 is substituted with a C3-C6 cycloalkylidene ring.

In certain embodiments, hetCyc 1 is piperidinyl or piperazinyl.

In certain embodiments, hetCyc 1 is piperazinyl.

Non-limiting examples of D when represented by hetCyc 1 include the structures:

where the asterisk indicates the point of attachment to the E group.

In one embodiment of the D-E group, D is hetCyc 1 and E is hydrogen. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is OH. In one embodiment, hetCyc 1 is a 5-6 membered heterocyclic ring having a ring nitrogen atom, wherein the ring is optionally substituted with trifluoro1-C3 alkyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is R a R b N— where R a is H or C1-C6 alkyl and R b is H, C1-C6 alkyl or phenyl. In one embodiment, hetCyc 1 is a 6 membered heterocyclic ring having a ring nitrogen atom, wherein the ring is optionally substituted with C1-C3 alkyl. Non-limiting examples include the structures:

In one embodiment of the D-E group, D is hetCyc 1 and E is C1-C6 alkyl optionally substituted with one to three fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is hydroxyC1-C6 alkyl optionally substituted with one to three fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is C1-C6 alkoxy optionally substituted with one to three fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is hydroxy(C1-C6 alkoxy) optionally substituted with one to three fluoros. A non-limiting examples include the structure:

In one embodiment, D is hetCyc 1 and E is (C1-C6 alkoxy)hydroxy C1-C6 alkyl optionally substituted with one to three fluoros. A non-limiting example includes the structure:

In one embodiment, D is hetCyc 1 and E is (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros. In one embodiment, hetCyc 1 is a 6-membered heterocyclic ring having 1-2 ring nitrogen atoms, wherein the heterocyclic ring is optionally substituted with cyclopropyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros. In one embodiment, hetCyc 1 is a 6-membered heterocyclic ring having a ring nitrogen atom, wherein the heterocyclic ring is optionally substituted with cyclopropyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is (C1-C6 alkoxy)C(═O)—. In one embodiment, hetCyc 1 is a 6-membered heterocyclic ring having 1-2 ring nitrogen atoms, wherein the heterocyclic ring is optionally substituted with cyclopropyl or C1-C3 alkyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is (C1-C6 alkoxy)(C1-C6 alkyl)C(═O)—. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is HC(═O)—. A non-limiting example is the structure:

In one embodiment, D is hetCyc 1 and E is Cyc 1 , Cyc 1 C(═O)—, or Cyc 1 (C1-C6 alkyl)C(═O)—, wherein in each instance, Cyc 1 is a C3-C6 cycloalkyl, wherein (a) Cyc 1 is optionally substituted with one or more substituents independently selected from the group consisting of OH, halogen, C1-C6 alkoxy, CN, hydroxyC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, and C1-C6 alkyl optionally substituted with 1-3 fluoros, or (b) Cyc 1 is substituted with phenyl, wherein the phenyl is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy and CF, or (c) Cyc 1 is substituted with a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy and CF 3 .

In one embodiment, D is hetCyc 1 and E is Cyc 1 , where Cyc 1 is a C3-C6 cycloalkyl, wherein the cycloalkyl is optionally substituted with one or more substituents independently selected from the group consisting of OH, halogen, C1-C6 alkoxy, CN, hydroxyC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, and C1-C6 alkyl optionally substituted with 1-3 fluoros. In one embodiment, Cyc 1 is a C3-C6 cycloalkyl optionally substituted with OH. Non-limiting examples when D is hetCyc 1 and E is Cyc 1 include the structures:

In one embodiment, D is hetCyc 1 and E is Cyc 1 C(═O)— where Cyc 1 is as defined for General Formula I. In one embodiment, Cyc 1 is a C3-C6 cycloalkyl, wherein the cycloalkyl is optionally substituted with one or more substituents independently selected from the group consisting of OH or halogen. In one embodiment, the cycloalkyl is substituted with phenyl. Non-limiting examples when D is hetCyc 1 and E is Cyc 1 C(═O)— include the structures:

In one embodiment, D is hetCyc 1 and E is Cyc 1 (C1-C6 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or more groups independently selected from the group consisting of OH, fluoro, C1-C3 alkoxy and R c R d N— where R c and R d are independently H or C1-C6 alkyl. In one embodiment, Cyc 1 is a C3-C6 cycloalkyl optionally substituted with one or more substituents independently selected from the group consisting of OH, halogen, C1-C6 alkoxy, CN, hydroxyC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, and C1-C6 alkyl optionally substituted with 1-3 fluoros. In one embodiment, the alkyl portion of Cyc 1 (C1-C6 alkyl)C(═O)— is unsubstituted. In one embodiment, Cyc 1 is unsubstituted. A non-limiting example when D is hetCyc 1 and E is Cyc 1 (C1-C6 alkyl)C(═O)— is the structure:

In one embodiment, D is hetCyc 1 and E is hetCyc 4 , hetCyc 4 C(═O)—, hetCyc 4 (C1-C3 alkyl)C(═O)—, (hetCyc 4 )C(═O)C1-C2 alkyl, or hetCyc 4 C(═O)NH—, wherein in each instance, hetCyc 4 is as defined for General Formula I.

In one embodiment, D is hetCyc 1 and E is hetCyc 4 , hetCyc 4 C(═O)—, hetCyc 4 (C1-C3 alkyl)C(═O)—, (hetCyc 4 )C(═O)C1-C2 alkyl, or hetCyc 4 C(═O)NH—, wherein in each instance hetCyc 4 is (a) a 5-6 membered heterocyclic ring, (b) a 7-8 membered bridged heterocyclic ring, (c) a 8-12 membered fused bicyclic heterocyclic ring, or (d) a 7-10 membered spirocyclic heterocyclic ring, wherein each of the heterocyclic rings has 1-2 ring heteroatoms independently selected from N and O, and wherein each of the heterocyclic rings is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy and (C1-C6 alkoxy)C1-C6 alkyl.

In one embodiment, hetCyc 4 is tetrahydrofuranyl, pyrrolidinyl, piperidinyl, morpholinyl or tetrahydro-2H-thiopyranyl 1,1-dioxide optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy and (C1-C6 alkoxy)C1-C6 alkyl.

In one embodiment, D is hetCyc 1 and E is hetCyc 4 , where hetCyc 4 is as defined for General Formula I. In one embodiment, hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N, O and S wherein the S is optionally oxidized to SO 2 , and wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy and (C1-C6 alkoxy)C1-C6 alkyl.

In one embodiment, D is hetCyc 1 and E is hetCyc 4 , wherein hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N, O, and S wherein the S is optionally oxidized to SO 2 and wherein the heterocyclic ring is optionally substituted with OH or C1-C6 alkoxy.

In one embodiment, D is hetCyc 1 and E is hetCyc 4 , wherein hetCyc 4 is a 4-6 membered heterocyclic ring having a ring heteroatom selected from O and S wherein the S is optionally oxidized to SO 2 , and wherein the heterocyclic ring is optionally substituted with OH or C1-C6 alkoxy.

Non-limiting examples when D is hetCyc 1 and E is hetCyc 4 include the structures:

In one embodiment, D is hetCyc 1 and E is hetCyc 4 C(═O)—, where hetCyc 4 is as defined for General Formula I. In one embodiment, hetCyc 4 is (a) a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N, O and S wherein said S is optionally oxidized to SO 2 , (b) a 7-8 membered bridged heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, (c) a 6-12 membered fused bicyclic heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O and optionally independently substituted with 1-2 C1-C6 alkyl substitutents, or (d) a 7-10 membered spirocyclic heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein each of said heterocyclic rings is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkyl)C(═O)—, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl.

In one embodiment, D is hetCyc 1 and E is hetCyc 4 C(═O)—, where hetCyc 4 is (a) a 5-6 membered heterocyclic ring, (b) a 7-8 membered bridged heterocyclic ring, (c) a 6-12 membered fused bicyclic heterocyclic ring, or (d) a 7-10 membered spirocyclic heterocyclic ring, wherein each of the heterocyclic rings has 1-2 ring heteroatoms independently selected from N and O, and wherein each of the heterocyclic rings is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy and (C1-C6 alkoxy)C1-C6 alkyl.

In one embodiment, D is hetCyc 1 and E is hetCyc 4 C(═O)—, where hetCyc 4 is (a) a 4-6 membered heterocyclic ring, (b) a 7-8 membered bridged heterocyclic ring, (c) a 6-12 membered fused bicyclic heterocyclic ring, or (d) a 7-10 membered spirocyclic heterocyclic ring, wherein each of the heterocyclic rings has 1-2 ring heteroatoms independently selected from N and O, and wherein each of the heterocyclic rings is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl wherein said phenyl is optionally substituted with one or more substituents selected from halogen, C1-C6 alkyl and C1-C6 alkoxy.

In one embodiment, D is pyrrolidinyl, piperidinyl or piperazinyl, and E is hetCyc 4 C(═O)—, where hetCyc 4 is (a) a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl (b) a 7-8 membered bridged heterocyclic ring having a ring nitrogen atom, (c) a 6-12 membered fused bicyclic heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O and optionally substituted with 1-2 groups independently selected from C1-C6 alkyl, or (d) a 7-10 membered spirocyclic heterocyclic ring a ring nitrogen atom.

In one embodiment, D is pyrrolidinyl, piperidinyl or piperazinyl, and E is hetCyc 4 C(═O)—, where hetCyc 4 is a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl. In one embodiment, the ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy and (C1-C6 alkoxy)C1-C6 alkyl.

Non-limiting examples when D is hetCyc 1 and E is hetCyc 4 C(═O)— include the structures:

In one embodiment, D is hetCyc 1 and E is hetCyc 4 (C1-C3 alkyl)C(═O)— where hetCyc 4 is as defined for General Formula I. In one embodiment, hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl wherein said phenyl is optionally substituted with one or more substituents selected from halogen, C1-C6 alkyl and C1-C6 alkoxy. In one embodiment, the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl.

In one embodiment, D is hetCyc 1 and E is hetCyc 4 (C1-C3 alkyl)C(═O)—, where hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the heterocyclic ring is unsubstituted or substituted with C1-C6 alkyl. In one embodiment, D is hetCyc 1 and E is hetCyc 4 (C1-C3 alkyl)C(═O)—, where hetCyc 4 is a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the heterocyclic ring is unsubstituted.

In one embodiment, D is piperazinyl and E is hetCyc 4 (C1-C3 alkyl)C(═O)—, where hetCyc 4 is a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the heterocyclic ring is unsubstituted or substituted with C1-C6 alkyl. In one embodiment, the ring is unsubstituted.

Non-limiting examples when D is hetCyc 1 and E is hetCyc 4 (C1-C3 alkyl)C(═O)— include the structures:

In one embodiment, D is hetCyc 1 and E is (hetCyc 4 )C(═O)C1-C2 alkyl, where hetCyc 4 is as defined for General Formula I. In one embodiment, hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl wherein said phenyl is optionally substituted with one or more substituents selected from halogen, C1-C6 alkyl and C1-C6 alkoxy. In one embodiment, the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy and (C1-C6 alkoxy)C1-C6 alkyl.

In one embodiment, D is hetCyc 1 and E is (hetCyc 4 )C(═O)C1-C2 alkyl, where hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the heterocyclic ring is unsubstituted. In one embodiment, D is piperazinyl and hetCyc 4 is a 4-6 membered heterocyclic ring having a ring nitrogen atom. In one embodiment, hetCyc 4 is 5-6 membered heterocyclic ring having a ring nitrogen atom.

A non-limiting example when D is hetCyc 1 and E is (hetCyc 4 )C(═O)C1-C2 alkyl is the structure:

In one embodiment, D is hetCyc 1 and E is hetCyc 4 C(═O)NH—, where hetCyc 4 is as defined for General Formula I. In one embodiment, hetCyc 4 is (a) a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein said ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, and (C1-C6 alkoxy)C1-C6 alkyl, (b) a 7-8 membered bridged heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, (c) a 8-12 membered fused bicyclic heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, or (d) a 7-10 membered spirocyclic heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O.

Non-limiting examples when D is hetCyc 1 and E is hetCyc 4 C(═O)NH— include the structures:

In one embodiment, D is hetCyc 1 and E is Ar 2 ; Ar 2 C(═O)—; Ar 2 C1-C6 alkyl; (Ar 2 )hydroxy C2-C6 alkyl; or Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N— where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O; wherein for each instance of E, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, CN, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and R i R j N— where R i and R j are independently H and C1-C6 alkyl. In one embodiment, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen and C1-C3 alkyl.

In one embodiment, D is hetCyc 1 and E is Ar 2 ; Ar 2 C(═O)—; Ar 2 C1-C6 alkyl; (Ar 2 )hydroxy C2-C6 alkyl; or Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N— where R e and R f are independently H or C1-C6 alkyl; wherein for each instance of E, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl and trifluoroC1-C3 alkyl. In one embodiment, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen and C1-C3 alkyl.

In one embodiment, D is hetCyc 1 and E is Ar 2 wherein Ar 2 is as defined for General Formula I. In one embodiment, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen. In one embodiment, hetCyc 1 is pyrrolidinyl, piperidinyl or morpholinyl. Non-limiting examples when D is hetCyc 1 and E is Ar 2 include the structures:

In one embodiment, D is hetCyc 1 and E is Ar 2 C(═O)— wherein Ar 2 is as defined for General Formula I. In one embodiment, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen or a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O. In one embodiment, hetCyc 1 is piperazinyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is Ar 2 C1-C6 alkyl wherein Ar 2 is as defined for General Formula I. In one embodiment, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy, CN, and R i R j N— where R i and R j are independently H and C1-C6 alkyl. In one embodiment, hetCyc 1 is piperazinyl, piperidinyl, azetidinyl, or piperazin-2-onyl. In one embodiment, E is Ar 2 C1-C2 alkyl where Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, CN, and R i R j N— where R i and R j are independently H and C1-C6 alkyl.

Non-limiting examples when D is hetCyc 1 and E is Ar 2 C1-C6 alkyl include the structures:

In one embodiment, D is hetCyc 1 and E is (Ar 2 )hydroxy C2-C6 alkyl wherein Ar 2 is as defined for General Formula I. In one embodiment, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen. In one embodiment, hetCyc 1 is piperazinyl.

Non-limiting examples when D is hetCyc 1 and E is (Ar 2 )hydroxy C2-C6 alkyl include the structures:

In one embodiment, D is hetCyc 1 and E is Ar 2 (C1-C3 alkyl)C(═O)—, wherein Ar 2 is as defined for General Formula I and the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H and C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O. In one embodiment, hetCyc 1 is piperazinyl. In one embodiment, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from halogen, CN, C1-C6 alkyl and C1-C6 alkoxy (optionally substituted with 1-3 fluoros).

In one embodiment, D is hetCyc 1 and E is Ar 2 (C1-C3 alkyl)C(═O)—, wherein Ar 2 is as defined for General Formula I and the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H and C1-C6 alkyl. In one embodiment, hetCyc 1 is piperazinyl.

Non-limiting examples when D is hetCyc 1 and E is Ar 2 (C1-C3 alkyl)C(═O)— include the structures:

In one embodiment, D is hetCyc 1 and E is hetAr 2 C(═O)—; (hetAr 2 )hydroxyC2-C6 alkyl; or hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O; wherein for each instance of E, hetAr 2 is a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, O and S and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, hydroxyC1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkoxy)C1-C6 alkyl, CN, and R′R″N— where R′ and R″ are independently H or C1-C6 alkyl.

In one embodiment, D is hetCyc 1 and E is hetAr 2 C(═O)—; (hetAr 2 )hydroxyC2-C6 alkyl; hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl; or hetAr 2 C1-C6 alkyl; wherein for each instance of E, hetAr 2 is a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N and O and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C3 alkyl, difluoroC1-C3 alkyl, trifluoroC1-C3 alkyl and hydroxyC1-C3 alkyl.

In one embodiment, hetAr 2 is pyridyl, pyridazinyl, imidazolyl, pyrazolyl or isoxazolyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C3 alkyl, difluoroC1-C3 alkyl, trifluoroC1-C3 alkyl, hydroxyC1-C6 alkyl, (C3-C6)cycloalkyl and (C1-C6 alkoxy)C1-C6 alkyl. In one embodiment, hetAr 2 is optionally substituted with one or more substituents independently selected C1-C3 alkyl.

In one embodiment, D is hetCyc 1 and E is hetAr 2 C(═O)—, where hetAr 2 is as defined for General Formula I. In one embodiment, hetAr 2 is a 5-6 membered heteroaryl ring having 1-2 ring heteroatoms independently selected from N and O and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, (C3-C6)cycloalkyl and (C1-C6 alkoxy)C1-C6 alkyl. In one embodiment, hetCyc 1 is piperazinyl.

Non-limiting examples when D is hetCyc 1 and E is hetAr 2 C(═O)— include the structures:

In one embodiment, D is hetCyc 1 and E is (hetAr 2 )hydroxyC2-C6 alkyl where hetAr 2 is as defined for General Formula I. In one embodiment, hetAr 2 is a 5-6 membered heteroaryl ring having 1-2 ring heteroatoms independently selected from N and O wherein said ring is unsubstituted. In one embodiment, hetAr 2 is pyridinyl. Non-limiting examples includes the structures:

In one embodiment, D is hetCyc 1 and E is hetAr 2 (C1-C3 alkyl)C(═O)—, wherein hetAr 2 is as defined for General Formula I and the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros) and R e R f N—, where R e and R f are independently H or C1-C6 alkyl. In one embodiment, the alkyl portion of hetAr 2 (C1-C3 alkyl)C(═O)— is unsubstituted. In one embodiment, hetAr 2 is a 5-6 membered heteroaryl ring having 1-2 ring nitrogen atoms and optionally substituted with one or more substituents independently selected from the group consisting of halogen and C1-C6 alkyl. In one embodiment, hetCyc 1 is piperazinyl.

Non-limiting examples D is hetCyc 1 and E is hetAr 2 (C1-C3 alkyl)C(═O)— include the structures:

In one embodiment, D is hetCyc 1 and E is R 1 R 2 NC(═O)—; R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with phenyl; R 1 R 2 NC(═O)C1-C2 alkyl; or R 1 R 2 NC(═O)NH—; where in each instance, R 1 is H, C1-C6 alkyl or (C1-C6 alkoxy)C1-C6 alkyl, and R 2 is H, C1-C6 alkyl (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C1-C6 alkyl (optionally substituted with 1-3 fluoros), Cyc 3 , hydroxyC1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C(═O), hetCyc 7 , Ar 3 , Ar 3 C1-C3 alkyl-, hydroxyC1-C6 alkoxy or (3-6C cycloalkyl)CH 2 O—.

In one embodiment, D is hetCyc 1 and E is R 1 R 2 NC(═O)—; R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with phenyl; R 1 R 2 NC(═O)C1-C2 alkyl; or R 1 R 2 NC(═O)NH—; where in each instance, R 1 is H or C1-C6 alkyl, and R 2 is H, C1-C6 alkyl (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C1-C6 alkyl (optionally substituted with 1-3 fluoros), Cyc 3 , hydroxyC1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C(═O), hetCyc 7 , Ar 3 or Ar 3 C1-C3 alkyl-.

In one embodiment, D is hetCyc 1 and E is R 1 R 2 NC(═O)—, where R 1 is H, C1-C6 alkyl or (C1-C6 alkoxy)C1-C6 alkyl, and R 2 is C1-C6 alkyl (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C1-C6 alkyl (optionally substituted with 1-3 fluoros), Cyc 3 , hydroxyC1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C(═O), hetCyc 7 , Ar 3 , Ar 3 C1-C3 alkyl-, hydroxyC1-C6 alkoxy or (3-6C cycloalkyl)CH 2 O—. In one embodiment, hetCyc 1 is pyrrolidinyl, piperidinyl (optionally substituted with C1-C3 alkyl), piperazinyl, morpholinyl or azetidinyl. In one embodiment, hetCyc 1 is pyrrolidinyl, piperidinyl (optionally substituted with C1-C3 alkyl), piperazinyl, or morpholinyl.

Non-limiting examples when D is hetCyc 1 and E is R 1 R 2 NC(═O)— include the structures:

In one embodiment, D is hetCyc 1 and E is R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the C1-C3 alkyl portion is optionally substituted with phenyl. In one embodiment, R 1 is H or C1-C6 alkyl and R 2 is H, C1-C6 alkyl (optionally substituted with 1-3 fluoros) or (C1-C6 alkoxy)C(═O)—. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is R 1 R 2 NC(═O)C1-C2 alkyl. In one embodiment, R 1 is H or C1-C6 alkyl and R 2 is C1-C6 alkyl (optionally substituted with 1-3 fluoros). Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is R 1 R 2 NC(═O)NH—, where R 1 is H or C1-C6 alkyl, and R 2 is C1-C6 alkyl (optionally substituted with 1-3 fluoros). Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is CH 3 SO 2 (C1-C6 alkyl)C(═O)—. A non-limiting example is the structure:

In one embodiment, D is hetCyc 1 and E is (C1-C6 alkyl)SO 2 —. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is (C3-C6 cycloalkyl)CH 2 SO 2 —. A non-limiting example is the structure:

In one embodiment, D is hetCyc 1 and E is hetCyc 1 -SO 2 —, where hetCyc 5 is a 5-6 membered heterocyclic ring having a ring heteroatom selected from O and N. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is R 4 R 5 NSO 2 —, where R 4 and R 5 are independently H or C1-C6 alkyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is R 6 C(═O)NH—, where R 6 is C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy, (C1-C6 alkoxy)(C1-C6 alkyl), phenyl or hetCyc 8 . Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is hetCyc 6 , where hetCyc 6 is a 5 membered heterocyclic ring having one or two ring heteroatoms independently selected from N and O, wherein the ring substituted with oxo and wherein the ring is further optionally substituted with one or more substituents independently selected from the group consisting of OH and C1-6 alkyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is hetAr 2 C1-C6 alkyl, where hetAr 2 is as defined for General Formula I. In one embodiment, D is hetCyc 1 and E is hetAr 2 C1-C6 alkyl, where hetAr 2 is a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N and O, and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, trifluoroC1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, CN and (R a R b N)C1-C6 alkyl; and hetCyc 1 is piperazinyl (optionally substituted with oxo), piperidinyl or pyrrolidinyl. In one embodiment, hetAr 2 is a 5-6-membered heteroaryl ring having 1-2 ring nitrogen atoms optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, trifluoroC1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, CN and (R a R b N)C1-C6 alkyl. In one embodiment, hetAr 2 is pyridyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, trifluoroC1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, CN and (R a R b N)C1-C6 alkyl. In one embodiment, hetAr 2 is pyridyl optionally substituted with C1-C6 alkoxy (optionally substituted with 1-3 fluoros). In one embodiment, hetAr 2 is a 5-membered heteroaryl ring having 1-2 ring nitrogen atoms optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, trifluoroC1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, CN and (R a R b N)C1-C6 alkyl.

Non-limiting examples when D is hetCyc 1 and E is hetAr 2 C1-C6 alkyl include the structures:

In one embodiment, D is hetCyc 1 and E is (hetCyc 4 )C1-C6 alkyl, where hetCyc 4 is as defined for General Formula I. In one embodiment, E is (hetCyc 4 )C1-C6 alkyl, where hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein said heterocyclic ring is optionally substituted with (C1-C6 alkyl)C(═O)—. In one embodiment, D is hetCyc 1 and E is hetCyc 4 (C1-C2 alkyl), where hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein said heterocyclic ring is optionally substituted with (C1-C6 alkyl)C(═O)—.

Non-limiting embodiments when D is hetCyc 1 and E is (hetCyc 4 )C1-C6 alkyl include the structures:

In one embodiment, D is hetCyc 1 and E is (C1-C6 alkoxy)C1-C6 alkyl wherein said alkoxy portion is optionally substituted with 1-3 fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is (C3-C6 cycloalkoxy)C1-C6 alkyl. A non-limiting example is the structure:

In one embodiment, D is hetCyc 1 and E is (C3-C6 cycloalkyl)C1-C6 alkyl wherein said cycloalkyl is optionally substituted with 1-2 fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is (R g R h N)C1-C6 alkyl wherein R g and R h are independently H or C1-C6 alkyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is Ar 2 —O—, where Ar 2 is as defined for General Formula I. In one embodiment, Ar 2 is phenyl optionally substituted with one or more halogens. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is (C1-C6 alkylSO 2 )C1-C6 alkyl. A non-limiting example is the structure:

In one embodiment, D is hetCyc 1 and E is (C1-C6 alkoxy)C(═O)NHC1-C6 alkyl. A non-limiting example is the structure:

In one embodiment, D is hetCyc 1 and E is (C3-C6 cycloalkyl)SO 2 — wherein said cycloalkyl is optionally substituted with C1-C6 alkyl. A non-limiting example includes the structure:

In one embodiment, D is hetCyc 1 and E is (N—(C1-C3 alkyl)pyridinonyl)C1-C3 alkyl. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 1 and E is (Ar 4 SO 2 )C1-C6 alkyl where Ar 4 is as defined for Formula I. In one embodiment, Ar 4 is unsubstituted phenyl. A non-limiting example when D is hetCyc 1 and E is (Ar 4 SO 2 )C1-C6 alkyl includes the structure:

In one embodiment, D is hetCyc 1 and E is (N—(C1-C3 alkyl)pyridinonyl)C1-C3 alkyl. Non-limiting examples include the structures:

In one embodiment of the D-E group, D is hetCyc 1 (wherein hetCyc 1 is a 4-6 membered heterocyclic ring having 2 ring atoms and is optionally substituted with a C3-C6 cycloalkylidene ring, or an oxo group) and the E group is on a ring nitrogen atom of the D ring, wherein E is selected from (a) hydrogen, (d) C1-C6 alkyl optionally substituted with one to three fluoros, (e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros, (h) (C1-C6 alkoxy)hydroxy C1-C6 alkyl optionally substituted with one to three fluoros, (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (k) (C1-C6 alkoxy)C(═O)—, (l) (C1-C6 alkoxy)(C1-C6 alkyl)C(═O)—, (n) Cyc 1 , (o) Cyc 1 C(═O)—, (p) Cyc 1 (C1-C6 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or more groups independently selected from the group consisting of OH, fluoro, C1-C3 alkoxy and R c R d N—, where R c and R d are independently H or C1-C6 alkyl, (q) hetCyc 4 , (r) hetCyc 4 C(═O)—, (s) hetCyc 4 (C1-C3 alkyl)C(═O)—, (t) (hetCyc 4 )C(═O)C1-C2 alkyl, (w) Ar 2 C(═O)—, (x) Ar 2 C1-C6 alkyl, (y) (Ar 2 )hydroxy C2-C6 alkyl, (z) Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, (aa) hetAr 2 C(═O)—, (bb) (hetAr 2 )hydroxyC2-C6 alkyl, (cc) hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, (dd) R 1 R 2 NC(═O)—, (ee) R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with phenyl, (ff) R 1 R 2 NC(═O)C1-C2 alkyl, (hh) CH 3 SO 2 (C1-C6 alkyl)C(═O)—, (ii) (C1-C6 alkyl)SO 2 —, (jj) (C3-C6 cycloalkyl)CH 2 SO 2 —, (kk) hetCyc 5 -SO 2 —, (ll) R 4 R 5 NSO 2 —, (nn) hetCyc 6 , (oo) hetAr 2 C1-C6 alkyl, (pp) (hetCyc 4 )C1-C6 alkyl, (qq) (C1-C6 alkoxy)C1-C6 alkyl wherein said alkoxy portion is optionally substituted with 1-3 fluoros, (rr) (C3-C6 cycloalkoxy)C1-C6 alkyl, (ss) (C3-C6 cycloalkyl)C1-C6 alkyl wherein said cycloalkyl is optionally substituted with 1-2 fluoros, (tt) (R g R h N)C1-C6 alkyl wherein R g and R h are independently H or C1-C6 alkyl, (vv) (C1-C6 alkylSO 2 )C1-C6 alkyl, (ww) (C1-C6 alkoxy)C(═O)NHC1-C6 alkyl, (C3-C6 cycloalkyl)SO 2 — wherein said cycloalkyl is optionally substituted with C1-C6 alkyl, (yy) (C3-C6 cycloalkyl)SO 2 — wherein said cycloalkyl is optionally substituted with C1-C6 alkyl, (aaa) (N—(C1-C3 alkyl)pyridinonyl)C1-C3 alkyl, or (bbb) (Ar 4 SO 2 )C1-C6 alkyl. In one embodiment, D is a piperazinyl ring.

In one embodiment of the D-E group, D is piperidinyl, pyrrolidinyl, azetidinyl or morphylinyl, each of which is optionally substituted with C1-C3 alkyl, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl, or trifluoroC1-C3 alkyl, wherein E is selected from (a) hydrogen, (b) OH, (c) R a R b N—, (f) C1-C6 alkoxy optionally substituted with one to three fluoros, (g) hydroxy(C1-C6 alkoxy) optionally substituted with one to three fluoros, (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (k) (C1-C6 alkoxy)C(═O)—, (m) HC(═O)—, (r) hetCyc 4 C(═O)—, (u) hetCyc 4 C(═O)NH—, (v) Ar 2 , (dd) R 1 R 2 NC(═O)—, (x) Ar 2 C1-C6 alkyl, (ff) R 1 R 2 NC(═O)C1-C2 alkyl, (gg) R 1 R 2 NC(═O)NH—, (ii) (C1-C6 alkyl)SO 2 —, (ll) R 4 R 5 NSO 2 —, (mm) R 6 C(═O)NH—, (nn) hetCyc 6 , or (uu) Ar 2 —O—. In one embodiment, D is a piperidinyl ring.

In one embodiment of Formula I, D is hetCyc 2 , where hetCyc 2 is a 7-8 membered bridged heterocyclic ring having 1-3 ring heteroatoms independently selected from N and O, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl. In one embodiment, hetCyc 2 is a 7-8 membered bridged heterocyclic ring having 1-2 ring nitrogen atoms, wherein the ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl. In one embodiment, hetCyc 2 is unsubstituted. Non-limiting examples of D when represented by hetCyc 2 include the structures:

where the asterisk indicates the point of attachment to the E group.

In one embodiment of Formula I, D is hetCyc 2 and E is (a) hydrogen, (b) OH, (c) R a R b N— where R a is H or C1-C6 alkyl and R b is H, C1-C6 alkyl or phenyl, (d) C1-C6 alkyl optionally substituted with one to three fluoros, (e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros, (f) C1-C6 alkoxy optionally substituted with one to three fluoros, (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (k) (C1-C6 alkoxy)C(═O)—(O) Cyc 1 C(═O)—, (w) Ar 2 C(═O)—, (x) Ar 2 C1-C6 alkyl, (y) (Ar 2 )hydroxy C2-C6 alkyl, (aa) hetAr 2 C(═O)—, (cc) hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O, (ee) R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein said alkyl portion is optionally substituted with phenyl, (oo) hetAr 2 C1-C6 alkyl or (qq) (C1-C6 alkoxy)C1-C6 alkyl wherein said alkoxy portion is optionally substituted with 1-3 fluoros.

In one embodiment, D is hetCyc 2 and E is hydrogen. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 2 and E is OH. A non-limiting example is the structure:

In one embodiment, D is hetCyc 2 and E is R a R b N— where R a is H or C1-C6 alkyl and R b is H, C1-C6 alkyl or phenyl. In one embodiment, D is hetCyc 2 and E is R a R b N— where R a and R b are H. A non-limiting example is the structure:

In one embodiment, D is hetCyc 2 and E is C1-C6 alkyl optionally substituted with one to three fluoros. A non-limiting example includes the structure:

In one embodiment, D is hetCyc 2 and E is C1-C6 alkoxy optionally substituted with one to three fluoros. A non-limiting example is the structure:

In one embodiment, D is hetCyc 2 and E is (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 2 and E is (C1-C6 alkoxy)C(═O)—. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 2 and E is Ar 2 C(═O)—, where Ar 2 is as defined for General Formula I. In one embodiment, Ar 2 is phenyl optionally substituted with one or more substituents independently selected from halogen and C1-C6 alkoxy (optionally substituted with 1-3 fluoros). Non-limiting examples when D is hetCyc 2 and E is Ar 2 C(═O) include the structures:

In one embodiment, D is hetCyc 2 and E is Ar 2 C1-C6 alkyl where Ar 2 is as defined for General Formula I. In one embodiment, Ar 2 is an unsubstituted phenyl. Non-limiting examples when D is hetCyc 2 and E is Ar 2 C1-C6 alkyl include the structures:

In one embodiment, D is hetCyc 2 and E is hetAr 2 C(═O)— where hetAr 2 is as defined for Formula I. In one embodiment hetAr 2 is a 6-membered heteroaryl ring having 1-2 ring nitrogen atoms and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, hydroxyC1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkoxy)C1-C6 alkyl, CN and R′R″N— where R′ and R″ are independently H or C1-C3 alkyl. In one embodiment hetAr 2 is pyridyl optionally substituted with one or more substituents independently selected from halogen and C1-C6 alkoxy (optionally substituted with 1-3 fluoros). Non-limiting examples when D is hetCyc 2 and E is hetAr 2 C(═O)— include the structures:

In one embodiment, D is hetCyc 2 and E is hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O, and hetAr 2 is as defined for Formula I. In one embodiment, E is hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is unsubstituted. In one embodiment, hetAr 2 is is a 6-membered heteroaryl ring having 1-2 ring nitrogen atoms and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, hydroxyC1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkoxy)C1-C6 alkyl, CN and R′R″N— where R′ and R″ are independently H or C1-C3 alkyl. In one embodiment hetAr 2 is pyridyl optionally substituted with one or more substituents independently selected from halogen. A non-limiting example D is hetCyc 2 and E is hetAr 2 (C1-C3 alkyl)C(═O)— includes the structure:

In one embodiment, D is hetCyc 2 and E is R 1 R 2 N(C1-C3 alkyl)C(═O)—. A non-limiting example is the structure:

In one embodiment, D is hetCyc 2 and E is hetAr 2 C1-C6 alkyl, where hetAr 2 is as defined for Formula I. In one embodiment, E is hetAr 2 C1-C6 alkyl wherein the alkyl portion is unsubstituted. In one embodiment, hetAr 2 is a 6-membered heteroaryl ring having 1-2 ring nitrogen atoms and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, hydroxyC1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkoxy)C1-C6 alkyl, CN and R′R″N— where R′ and R″ are independently H or C1-C3 alkyl. In one embodiment hetAr 2 is pyridyl optionally substituted with C1-C6 alkoxy (optionally substituted with 1-3 fluoros). Non-limiting examples when D is hetCyc 2 and E is hetAr 2 C1-C6 alkyl include the structures:

In one embodiment, D is hetCyc 2 and E is (C1-C6 alkoxy)C1-C6 alkyl wherein said alkoxy portion is optionally substituted with 1-3 fluoros. A non-limiting example includes the structure:

In one embodiment, D is hetCyc 2 (where hetCyc 2 is a 7-8 membered bridged heterocyclic ring having two ring nitrogen atoms, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl), and E is on a ring nitrogen atom of hetCyc 2 wherein E is (a) hydrogen, (d) C1-C6 alkyl optionally substituted with one to three fluoros, (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (w) Ar 2 C(═O)—, (x) Ar 2 C1-C6 alkyl, (aa) hetAr 2 C(═O)—, (oo) hetAr 2 C1-C6 alkyl, or (qq) (C1-C6 alkoxy)C1-C6 alkyl wherein said alkoxy portion is optionally substituted with 1-3 fluoros.

In one embodiment, D is hetCyc 2 (where hetCyc 2 is a 7-8 membered bridged heterocyclic ring having one ring nitrogen atom, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl), and E is on a ring carbon atom of hetCyc 2 wherein E is (b) OH, (c) R a R b N— where R a is H or C1-C6 alkyl and R b is H, C1-C6 alkyl or phenyl, or (f) C1-C6 alkoxy optionally substituted with one to three fluoros.

In one embodiment of Formula I, D is hetCyc 3 , where hetCyc 3 is a 7-11 membered heterospirocyclic ring having 1-2 ring heteroatoms independently selected from N and O and wherein the ring is optionally substituted with C1-C3 alkyl. In one embodiment, hetCyc 3 is unsubstituted. Non-limiting examples when D is represented by hetCyc 3 include the structures:

where the asterisk indicates the point of attachment to the E group.

In one embodiment, D is hetCyc 3 and E is selected from (a) hydrogen, (c) R a R b N— where R a is H or C1-C6 alkyl and R b is H, C1-C6 alkyl or phenyl, (d) C1-C6 alkyl optionally substituted with one to three fluoros, (e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros, (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (k) (C1-C6 alkoxy)C(═O)—, (o) Cyc 1 C(═O)—, (p) Cyc 1 (C1-C6 alkyl)C(═O), (r) hetCyc 4 C(═O)—, (w) Ar 2 C(═O)—, (x) Ar 2 C1-C6 alkyl, (y) (Ar 2 )hydroxy C2-C6 alkyl, (z) Ar 2 (C1-C3 alkyl)C(═O)— wherein said alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O, (dd) R 1 R 2 NC(═O), (ee) R 1 R 2 N(C1-C3 alkyl)C(═O)—, (mm) R 6 C(═O)NH—, (xx) (C3-C6 cycloalkoxy)C(═O)— and (zz) Ar 4 CH 2 OC(═O)—.

In one embodiment, D is hetCyc 3 (wherein a 7-11 membered heterospirocyclic ring having two ring nitrogen atoms), wherein the ring is optionally substituted with C1-C3 alkyl), and E is on a ring nitrogen atom of ring D, and E is selected from (a) hydrogen, (d) C1-C6 alkyl optionally substituted with one to three fluoros, (e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros, (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (k) (C1-C6 alkoxy)C(═O)—, (o) Cyc 1 C(═O)—, (p) Cyc 1 (C1-C6 alkyl)C(═O), (r) hetCyc 4 C(═O)—, (w) Ar 2 C(═O)—, (x) Ar 2 C1-C6 alkyl, (y) (Ar 2 )hydroxy C2-C6 alkyl, (z) Ar 2 (C1-C3 alkyl)C(═O)— wherein said alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O, (dd) R 1 R 2 NC(═O), (ee) R 1 R 2 N(C1-C3 alkyl)C(═O)—, (xx) (C3-C6 cycloalkoxy)C(═O)— and (zz) Ar 4 CH 2 OC(═O)—.

In one embodiment, D is hetCyc 3 (wherein hetCyc 3 is a 7-11 membered heterospirocyclic ring having one ring nitrogen atom, wherein the ring is optionally substituted with C1-C3 alkyl), and E is on a ring carbon atom of ring D, and E is selected from (a) hydrogen, (c) R a R b N— where R a is H or C1-C6 alkyl and R b is H, C1-C6 alkyl or phenyl, and (mm) R 6 C(═O)NH—.

In one embodiment, D is hetCyc 3 and E is hydrogen. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is R a R b N— where R a is H or C1-C6 alkyl and R b is H, C1-C6 alkyl or phenyl. In one embodiment, R a and R b are H. A non-limiting example is the structure:

In one embodiment, D is hetCyc 3 and E is C1-C6 alkyl optionally substituted with one to three fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is hydroxyC1-C6 alkyl optionally substituted with one to three fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is (C1-C6 alkoxy)C(═O)—. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is Cyc 1 C(═O)—, where Cyc 1 is as defined for General Formula I. In one embodiment, Cyc 1 is unsubstituted. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is Cyc 1 (C1-C6 alkyl)C(═O)— wherein said alkyl portion is optionally substituted with one or more groups independently selected from the group consisting of OH, fluoro, C1-C3 alkoxy and R c R d N—, where R c and R d are independently H or C1-C6 alkyl, and Cyc 1 is as defined for General Formula I.

In one embodiment, D is hetCyc 3 and E is Cyc 1 (C1-C6 alkyl)C(═O)— wherein said alkyl portion is unsubstituted, and Cyc 1 is as defined for General Formula I. In one embodiment, Cyc 1 is an unsubstituted C3-C6 cycloalkyl.

Non-limiting examples when D is hetCyc 3 and E is Cyc 1 (C1-C6 alkyl)C(═O)— include the structures:

In one embodiment, D is hetCyc 3 and E is hetCyc 4 C(═O)—, where hetCyc 4 is as defined for General Formula I. In one embodiment, hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein said ring is unsubstituted. A non-limiting example when D is hetCyc 3 and E is hetCyc 4 C(═O)— is the structure:

In one embodiment, D is hetCyc 3 and E is Ar 2 C(═O)— where Ar 2 is as defined for General Formula I. In one embodiment, Ar 2 is unsubstituted. A non-limiting example is the structure:

In one embodiment, D is hetCyc 3 and E is Ar 2 C1-C6 alkyl. In one embodiment, Ar 2 is phenyl which is unsubstituted. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O, and Ar 2 is as defined for General Formula I. In one embodiment, D is hetCyc 3 and E is Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is unsubstituted. In one embodiment, Ar 2 is phenyl which is unsubstituted. A non-limiting example is the structure:

In one embodiment, D is hetCyc 3 and E is R 1 R 2 NC(═O)— where R 1 and R 2 are as defined for General Formula I. In one embodiment, R 1 is H or C1-C6 alkyl and R 2 is H or C1-C6 alkyl optionally substituted with 1-3 fluoros. Non-limiting examples include the structures:

In one embodiment, D is hetCyc 3 and E is R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the C1-C3 alkyl portion is optionally substituted with phenyl, and R 1 and R 2 are as defined for General Formula I. In one embodiment, R 1 is H or C1-C6 alkyl and R 2 is H or C1-C6 alkyl optionally substituted with 1-3 fluoros. A non-limiting example is the structure:

In one embodiment, D is hetCyc 3 and E is R 6 C(═O)NH—, where R 6 is C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, phenyl or hetCyc 8 . In one embodiment, R 6 is C1-C6 alkoxy. A non-limiting example is the structure:

In one embodiment, D is hetCyc 3 and E is (C3-C6 cycloalkoxy)C(═O)—. A non-limiting example is the structure:

In one embodiment, D is hetCyc 3 and E is Ar 4 CH 2 OC(═O)—. A non-limiting example is the structure:

In one embodiment of Formula I, D is hetCyc 9 , where hetCyc 9 is a fused 9-10 membered heterocyclic ring having 1-3 ring nitrogen atoms and optionally substituted with oxo

where the asterisk indicates the point of attachment to the E group.

In one embodiment, General Formula I includes compounds of Formula I-A, wherein X 1 is CH or CH 3 , X 2 is CH, X 3 is CH, and X 3 is CH; and A, B, D and E are as defined for General Formula I.

In one embodiment, General Formula I includes compounds of Formula I-B, wherein X 1 is N, CH or CH 3 , X 2 is CH or N, X 3 is CH or N, and X 3 is CH or N, wherein one of X 1 , X 2 , X 3 and X 4 is N; and A, B, D and E are as defined for General Formula I.

In one embodiment, General Formula I includes compounds of Formula I-C, wherein B is hetAr 1 , wherein hetAr 1 is a 5-membered heteroaryl ring having 1-2 ring nitrogen atoms, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, and hydroxyC1-C6 alkyl; and X 1 , X 2 , X 3 , X 4 , A, D and E are as defined for General Formula I.

In one embodiment, General Formula I includes compounds of Formula I-D, wherein D is hetCyc 1 or hetCyc 3 , where hetCyc 1 is a 4-6 membered heterocyclic ring having 1-2 ring atoms selected from N and O, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl, trifluoroC1-C3 alkyl, OH, or the heterocyclic ring is substituted with a C3-C6 cycloalkylidene ring, or said heterocyclic ring is substituted with an oxo group; hetCyc 3 is a 7-11 membered heterospirocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the ring is optionally substituted with C1-C3 alkyl; and X 1 , X 2 , X 3 , X 4 , A, B and E are as defined for General Formula I. In one embodiment of Formula I-D, D is hetCyc 1 .

In one embodiment of Formula I-D, D is hetCyc 1 where hetCyc 1 is a 5-6 membered heterocyclic ring having 1-2 ring nitrogen atoms, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl; and X 1 , X 2 , X 3 , X 4 , A, B and E are as defined for General Formula I. In one embodiment of Formula I-D, D is hetCyc 1 where hetCyc 1 is piperazinyl or piperidinyl, wherein the piperidinyl ring is optionally substituted with C1-C3 alkyl, and X 1 , X 2 , X 3 , X 4 , A, B and E are as defined for General Formula I. In one embodiment of Formula I-D, D is hetCyc 1 where hetCyc 1 is piperazinyl, and X 1 , X 2 , X 3 , X 4 , A, B and E are as defined for General Formula I.

In one embodiment of Formula I-D, D is hetCyc 3 wherein the hetCyc 3 is optionally substituted with C1-C3 alkyl, and X 1 , X 2 , X 3 , X 4 , A, B and E are as defined for General Formula I. In one embodiment of Formula I-D, D is hetCyc 3 wherein hetCyc 3 is unsubstituted.

In one embodiment, Formula I includes compounds of Formula I-E, wherein:

X 1 is CH or N;

X 2 is CH or N;

X 3 is CH;

X 4 is CH;

wherein zero, one or two of X 1 and X 2 is N;

A is H, Cl or CN;

B is hetAr 1 ;

hetAr 1 is a 5-membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, S and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, hydroxyC1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, cyanoC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, (C1-C4 alkoxy)CH 2 C(═O)—, (C1-C4 alkoxy)C(═O)C1-C3 alkyl, C3-C6 cycloalkyl, (R a R b N)C1-C6 alkyl and hetCyc a ;

D is hetCyc 1 or hetCyc 3 ;

hetCyc 1 is a 4-6 membered heterocyclic ring having 1-2 ring nitrogen atoms, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl, or said heterocyclic ring is substituted with an oxo group;

hetCyc 3 is a 7-11 membered heterospirocyclic ring having 2 ring nitrogen atoms, wherein the ring is optionally substituted with C1-C3 alkyl;

E is

(a) hydrogen,

(d) C1-C6 alkyl optionally substituted with one to three fluoros,

(e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros,

(i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros,

(j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros,

(k) (C1-C6 alkoxy)C(═O)—,

(o) Cyc 1 C(═O)—,

(r) hetCyc 4 C(═O)—,

(x) Ar 2 C1-C6 alkyl,

(y) (Ar 2 )hydroxy C2-C6 alkyl,

(z) Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl (optionally substituted with 1-3 fluoros), hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O,

(cc) hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O,

(dd) R 1 R 2 NC(═O)—,

(ee) R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with phenyl,

(ii) (C1-C6 alkyl)SO 2 —, or

(mm) R 6 C(═O)NH—;

Cyc 1 is a C3-C6 cycloalkyl, wherein (a) the cycloalkyl is optionally substituted with one or more substituents independently selected from the group consisting of OH, halogen, C1-C6 alkoxy, CN, hydroxyC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, and C1-C6 alkyl optionally substituted with 1-3 fluoros, or (b) the cycloalkyl is substituted with phenyl, wherein the phenyl is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy and CF, or (c) the cycloalkyl is substituted with a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxy and CF 3 ;

hetCyc 4 is a 4-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N, O and S wherein said S is optionally oxidized to SO 2 and is optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkyl)C(═O)—, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and phenyl wherein said phenyl is optionally substituted with one or more substituents selected from halogen, C1-C6 alkyl and C1-C6 alkoxy;

Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, CN, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and R i R j N— where R i and R j are independently H and C1-C6 alkyl;

hetAr 2 is a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, O and S, and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkoxy)C1-C6 alkyl, CN and R′R″N— where R′ and R″ are independently H or C1-C3 alkyl;

R 1 is H, C1-C6 alkyl or (C1-C6 alkoxy)C1-C6 alkyl;

R 2 is H, C1-C6 alkyl (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C1-C6 alkyl (optionally substituted with 1-3 fluoros), Cyc 3 , hydroxyC1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy(C(═O), hetCyc 7 , Ar 3 , Ar 3 C1-C3 alkyl-, hydroxyC1-C6 alkoxy or (C3-C6 cycloalkyl)CH 2 O—;

Cyc 3 is a 3-6 membered carbocyclic ring optionally substituted with 1-2 groups independently selected from the group consisting of C1-C6 alkoxy, OH and halogen;

Ar 3 is phenyl optionally substituted with one or more substituents independently selected from halogen, C1-C3 alkyl, C1-C3 alkoxy, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl and trifluoroC1-C3 alkyl;

hetCyc 7 is a 5-6 membered heterocyclic ring having a ring heteroatom selected from O and N wherein the ring is optionally substituted with C1-C6 alkyl;

R 6 is C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy, (C1-C6 alkoxy)C1-C6 alkyl, phenyl or hetCyc 8 ; and

hetCyc 8 is a 5-6 membered heterocyclic ring having a ring heteroatom selected from O and N, wherein the heterocyclic ring is optionally substituted with C1-C6 alkyl.

In one embodiment of Formula I-E, hetAr 1 is a 5-membered heteroaryl ring having 1-2 ring nitrogen atoms, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl. In one embodiment, B is pyrazolyl or imidazolyl optionally substituted with C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl or hydroxyC1-C6 alkyl. In one embodiment, B is pyrazolyl optionally substituted with C1-C6 alkyl.

In one embodiment of Formula I-E, hetCyc 1 is piperazinyl and E is (a) hydrogen, (d) C1-C6 alkyl optionally substituted with one to three fluoros, (e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros, (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (k) (C1-C6 alkoxy)C(═O)—, (o) Cyc 1 C(═O)—, (r) hetCyc 4 C(═O)—, (x) Ar 2 C1-C6 alkyl, (y) (Ar 2 )hydroxy C2-C6 alkyl, (z) Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, (cc) hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl, (dd) R 1 R 2 NC(═O)—, (ee) R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with phenyl, (ii) (C1-C6 alkyl)SO 2 —, or (mm) R 6 C(═O)NH—. In some such embodiments, E is (d) C1-C6 alkyl optionally substituted with one to three fluoros, (e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros, (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (o) Cyc 1 C(═O)—, (r) hetCyc 4 C(═O)—, (x) Ar 2 C1-C6 alkyl, or (y) (Ar 2 )hydroxy C2-C6 alkyl.

In one embodiment of Formula I-E, hetCyc 1 is piperazinyl and E is (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, or (r) hetCyc 4 C(═O)—.

In one embodiment of Formula I-E, hetCyc 1 is piperazinyl and E is (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros.

In one embodiment of Formula I-E, hetCyc 1 is piperazinyl and E is hetCyc 4 C(═O)—. In one embodiment of Formula I-E, hetCyc 1 is piperazinyl and E is hetCyc 4 C(═O)— where hetCyc 4 is pyrrolidinyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, OH, CN, C1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy and (C1-C6 alkoxy)C1-C6 alkyl.

In one embodiment of Formula I-E, hetCyc 1 is piperazinyl and E is hetCyc 4 C(═O)—, where hetCyc 4 is pyrrolidinyl optionally substituted with C1-C6 alkoxy.

In one embodiment of Formula I-E, hetCyc 1 is piperazinyl and E is (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros.

In one embodiment of Formula I-E, X 1 is N and each of X 2 , X 3 and X 4 is CH.

In one embodiment of Formula I-E, A is CN.

In one embodiment of Formula I-E, A is Cl.

In one embodiment, Formula I includes compounds of Formula I-F, wherein:

X 1 is N and each of X 2 , X 3 and X 4 is CH;

A is CN or Cl;

B is hetAr 1 ;

hetAr 1 is a 5-membered heteroaryl ring having 1-2 ring nitrogen atoms, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl;

D is hetCyc 1 ;

hetCyc 1 is piperazinyl;

E is (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, or (r) hetCyc 4 C(═O)—; and

hetCyc 4 is as defined for General Formula I.

In one embodiment of Formula I-F, hetAr 1 is pyrazolyl optionally substituted one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl. In one embodiment, B is pyrazolyl or imidazolyl optionally substituted with C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl or hydroxyC1-C6 alkyl. In one embodiment of Formula I-F, hetAr 1 is pyrazolyl optionally substituted one or more substituents independently selected from the group consisting of C1-C6 alkyl. In one embodiment, B is pyrazolyl or imidazolyl optionally substituted with C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl or hydroxyC1-C6 alkyl.

In one embodiment of Formula I-F, hetCyc 4 is a 5-membered heterocyclic ring having a ring nitrogen atom, wherein the heterocyclic ring is optionally substituted with C1-C6 alkoxy.

In one embodiment of Formula I-F, A is CN.

In one embodiment, Formula I includes compounds of Formula I-G, wherein:

X 1 is N and each of X 2 , X 3 and X 4 is CH;

A is CN;

B is hetAr 1 ;

hetAr 1 is a 5-membered heteroaryl ring having 2 ring nitrogen atoms, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl;

D is hetCyc 1 ;

hetCyc 1 is piperazinyl;

E is (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros, or (r) hetCyc 4 C(═O)—; and

hetCyc 4 is a 5-membered heterocyclic ring having a ring nitrogen atom, wherein the heterocyclic ring is optionally substituted with C1-C6 alkoxy.

In one embodiment of Formula I-G, B is pyrazolyl optionally substituted one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl. In one embodiment of Formula I-G, B is pyrazolyl optionally substituted one or more substituents independently selected from the group consisting of C1-C6 alkyl.

In one embodiment of Formula I-G, E is (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros.

In one embodiment of Formula I-G, E is (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros.

In one embodiment of Formula I-G, E is (r) hetCyc 4 C(═O)—.

In one embodiment, Formula I includes compounds of Formula I-H wherein:

X 1 is N and each of X 2 , X 3 and X 4 is CH;

A is CN;

B is hetAr 1 ;

hetAr 1 is a 5-membered heteroaryl ring having 1-2 ring nitrogen atoms, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl;

D is hetCyc 3 ;

hetCyc 3 is a 7-11 membered heterospirocyclic ring having 1-2 ring heteroatoms independently selected from N and O, wherein the ring is optionally substituted with C1-C3 alkyl; and

E is as defined for General Formula I.

In one embodiment of Formula I-H, E is (a) hydrogen; (e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros; (i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros; (j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros; (k) (C1-C6 alkoxy)C(═O)—; (o) Cyc 1 C(═O)—; (w) Ar 2 C(═O)—; or (z) Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl; or (mm) R 6 C(═O)NH—.

In one embodiment of Formula I-H, E is (k) (C1-C6 alkoxy)C(═O)— or (o) Cyc 1 C(═O)—.

In one embodiment, Formula I includes compounds of Formula I-I, wherein:

X 1 , X 2 , X 3 and X 4 are CH;

A is H, Cl or CN;

B is hetAr 1 ;

hetAr 1 is a 5-membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, S and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, hydroxyC1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, cyanoC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, (C1-C4 alkoxy)CH 2 C(═O)—, (C1-C4 alkoxy)C(═O)C1-C3 alkyl, C3-C6 cycloalkyl, (R a R b N)C1-C6 alkyl and hetCyc a ;

D is hetCyc 1 ;

hetCyc 1 is a 5-6 membered heterocyclic ring having 1-2 ring nitrogen atoms, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl;

E is

(a) hydrogen,

(i) (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros,

(j) (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros,

(k) (C1-C6 alkoxy)C(═O)—,

(ee) R 1 R 2 N(C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with phenyl, or

(ii) (C1-C6 alkyl)SO 2 ;

R 1 is H or C1-C6 alkyl;

R 2 is H, C1-C6 alkyl (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy)C1-C6 alkyl (optionally substituted with 1-3 fluoros), Cyc 3 , hydroxyC1-C6 alkyl (optionally substituted with 1-3 fluoros), C1-C6 alkoxy (optionally substituted with 1-3 fluoros), (C1-C6 alkoxy(C(═O), hetCyc 7 , Ar 3 or Ar 3 C1-C3 alkyl-;

Cyc 3 is a 3-6 membered carbocyclic ring optionally substituted with 1-2 groups independently selected from the group consisting of C1-C6 alkoxy, OH and halogen;

Ar 3 is phenyl optionally substituted with one or more substituents independently selected from halogen, C1-C3 alkyl, C1-C3 alkoxy, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl and trifluoroC1-C3 alkyl; and

hetCyc 7 is a 5-6 membered heterocyclic ring having a ring heteroatom selected from O and N wherein the ring is optionally substituted with C1-C6 alkyl.

In one embodiment of Formula I-I, hetAr 1 is a 5-membered heteroaryl ring having 2 ring nitrogen atoms, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl.

In one embodiment, Formula I includes compounds of Formula I-I wherein

X 1 is N and each of X 2 , X 3 and X 4 is CH;

A is CN or Cl;

B is hetAr 1 ;

hetAr 1 is a 5-membered heteroaryl ring having 1-2 ring nitrogen atoms, wherein said heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl;

D is hetCyc 1 ;

hetCyc 1 is piperazinyl;

E is (d) C1-C6 alkyl optionally substituted with one to three fluoros, (e) hydroxyC1-C6 alkyl optionally substituted with one to three fluoros, (o) Cyc 1 C(═O)—, (x) Ar 2 C1-C6 alkyl, (y) (Ar 2 )hydroxy C2-C6 alkyl, or (bb) (hetAr 2 )hydroxyC2-C6 alkyl; and

Ar 2 and hetAr 2 are as defined for General Formula I.

In one embodiment, Formula I includes compounds of Formula I-J, wherein:

X 1 is N and each of X 2 , X 3 and X 4 is CH;

A is CN;

B is hetAr 1 ;

hetAr 1 is a 5-membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, S and O, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, hydroxyC1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, cyanoC1-C6 alkyl, (C1-C6 alkoxy)C1-C6 alkyl, (C1-C4 alkoxy)CH 2 C(═O)—, (C1-C4 alkoxy)C(═O)C1-C3 alkyl, C3-C6 cycloalkyl, (R a R b N)C1-C6 alkyl, and hetCyc a ;

D is hetCyc 1 ;

hetCyc 1 is piperazinyl;

E is (x) Ar 2 C1-C6 alkyl or (oo) hetAr 2 C1-C6 alkyl;

Ar 2 is phenyl optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy (optionally substituted with 1-3 fluoros), fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, CN, a 5-6 membered heterocyclic ring having 1-2 ring heteroatoms independently selected from N and O, and R i R j N— where R i and R j are independently H and C1-C6 alkyl; and

hetAr 2 is a 5-6 membered heteroaryl ring having 1-3 ring heteroatoms independently selected from N, O and S and optionally substituted with one or more substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl, (C3-C6)cycloalkyl, (C1-C6 alkoxy)C1-C6 alkyl, CN and R′R″N— where R′ and R″ are independently H or C1-C3 alkyl.

In one embodiment of Formula I-J, hetAr 1 is a 5-membered heteroaryl ring having 1-2 ring nitrogen atoms, wherein the heteroaryl ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl. In one embodiment, B is pyrazolyl or imidazolyl optionally substituted with C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl or hydroxyC1-C6 alkyl. In one embodiment, B is pyrazolyl optionally substituted with C1-C6 alkyl.

In one embodiment of Formula I-J, E is (x) Ar 2 C1-C6 alkyl or (oo) hetAr 2 C1-C6 alkyl. In one embodiment of Formula I-J, E is hetAr 2 C1-C6 alkyl.

In one embodiment of Formula I-J, B is pyrazolyl optionally substituted one or more substituents independently selected from the group consisting of C1-C6 alkyl, fluoroC1-C6 alkyl, difluoroC1-C6 alkyl, trifluoroC1-C6 alkyl and hydroxyC1-C6 alkyl. In one embodiment of Formula I-J, B is pyrazolyl optionally substituted one or more substituents independently selected from the group consisting of C1-C6 alkyl.

It will be appreciated that certain compounds provided herein may contain one or more centers of asymmetry and may therefore be prepared and isolated in a mixture of isomers such as a racemic mixture, or in an enantiomerically pure form.

It will further be appreciated that the compounds of General Formula I or their salts may be isolated in the form of solvates, and accordingly that any such solvate is included within the scope of the present invention. For example, compounds of General Formula I and salts thereof can exist in unsolvated as well as solvated forms with pharmaceutically acceptable solvents such as water, ethanol, and the like.

The compounds of General Formula I include pharmaceutically acceptable salts thereof. In addition, the compounds of General Formula I also include other salts of such compounds which are not necessarily pharmaceutically acceptable salts, and which may be useful as intermediates for preparing and/or purifying compounds of General Formula I and/or for separating enantiomers of compounds of Formula I. Non-limiting examples of salts include monochloride, dichloride, trifluoroacetic acid, and di-trifluoroacetic acid salts of compounds of Formula I.

In one embodiment, the compounds of General Formula I include the compounds of Examples 1-567, 569-570, 572, 574-654, and 656-744 and stereoisomers and pharmaceutically acceptable salts and solvates thereof. In one embodiment, the compounds of Examples 1-567, 569-570, 572, 574-654, and 656-744 are in the free base form. In one embodiment, the compounds of Examples 1-567, 569-570, 572, 574-654, and 656-744 are monochloride, dichloride, trifluoroacetic acid, or di-trifluoroacetic acid salts.

In some embodiments, the compounds provided herein exhibit potent and selective RET inhibition. For example, the compounds provided herein exhibit nanomolar potency against wild type RET and select RET mutants, including the KIF5B-RET fusion and V804M gatekeeper mutation, with minimal activity against related kinases.

In some embodiments, the compounds of General Formula I or a pharmaceutically acceptable salt or solvate thereof, selectively target a RET kinase. For example, a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, can selectively target a RET kinase over another kinase or non-kinase target.

In some embodiments, a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, exhibits at least a 30-fold selectivity for a RET kinase over another kinase. For example, a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, exhibits at least a 40-fold selectivity; at least a 50-fold selectivity; at least a 60-fold selectivity; at least a 70-fold selectivity; at least a 80-fold selectivity; at least a 90-fold selectivity; or at least 100-fold selectivity for a RET kinase over another kinase. In some embodiments, selectivity for a RET kinase over another kinase is measured in a cellular assay (e.g., a cellular assay as provided herein).

In some embodiments, the compounds provided herein can exhibit selectivity for a RET kinase over a KDR kinase (e.g., VEGFR 2 ). In some embodiments, the selectivity for a RET kinase over a KDR kinase is observed without loss of gatekeeper mutant potency. In some embodiments, the selectivity over a KDR kinase is at least 10-fold (e.g., at least a 40-fold selectivity; at least a 50-fold selectivity; at least a 60-fold selectivity; at least a 70-fold selectivity; at least a 80-fold selectivity; at least a 90-fold selectivity; or at least 100-fold) as compared to the inhibition of KIF5B-RET (i.e. the compounds were more potent against KIF5B-RET than KDR). In some embodiments, the selectivity for a RET kinase over a KDR kinase is about 30-fold. Without being bound by any theory, potent KDR kinase inhibition is believed to be a common feature among multikinase inhibitors (MKIs) that target RET and may be the source of the dose-limiting toxicities observed with such compounds.

In some embodiments, inhibition of V804M was similar to that observed for wild-type RET. For example, inhibition of V804M was within about 2-fold (e.g., about 5-fold, about 7-fold, about 10-fold) of inhibition of wild-type RET (i.e. the compounds were similarly potent against wild-type RET and V804M). In some embodiments, the compounds provided herein exhibit selective cytotoxicity to RET-mutant cells.

In some embodiments, the compounds of General Formula I or a pharmaceutically acceptable salt or solvate thereof, exhibit one or more of high GI absorption, low clearance, and low potential for drug-drug interactions.

The term “pharmaceutically acceptable” indicates that the substance or composition is compatible chemically and/or toxicologically, with the other ingredients comprising a formulation, and/or the patient being treated therewith.

Compounds provided herein may also contain unnatural proportions of atomic isotopes at one or more of the atoms that constitute such compounds. That is, an atom, in particular when mentioned in relation to a compound according to Formula I, comprises all isotopes and isotopic mixtures of that atom, either naturally occurring or synthetically produced, either with natural abundance or in an isotopically enriched form. For example, when hydrogen is mentioned, it is understood to refer to 1 H, 2 H, 3 H or mixtures thereof; when carbon is mentioned, it is understood to refer to 11 C, 12 C, 13 C, 14 C or mixtures thereof; when nitrogen is mentioned, it is understood to refer to 13 N, 14 N, 15 N or mixtures thereof; when oxygen is mentioned, it is understood to refer to 14 O, 15 O, 16 O, 17 O, 18 O or mixtures thereof; and when fluoro is mentioned, it is understood to refer to 18 F, 19 F or mixtures thereof. The compounds provided herein therefore also comprise compounds with one or more isotopes of one or more atom, and mixtures thereof, including radioactive compounds, wherein one or more non-radioactive atoms has been replaced by one of its radioactive enriched isotopes. Radiolabeled compounds are useful as therapeutic agents, e.g., cancer therapeutic agents, research reagents, e.g., assay reagents, and diagnostic agents, e.g., in vivo imaging agents. All isotopic variations of the compounds provided herein, whether radioactive or not, are intended to be encompassed within the scope of the present invention.

For illustrative purposes, Schemes 1-4 show general methods for preparing the compounds provided herein as well as key intermediates. For a more detailed description of the individual reaction steps, see the Examples section below. Those skilled in the art will appreciate that other synthetic routes may be used to synthesize the inventive compounds. Although specific starting materials and reagents are depicted in the Schemes and discussed below, other starting materials and reagents can be easily substituted to provide a variety of derivatives and/or reaction conditions. In addition, many of the compounds prepared by the methods described below can be further modified in light of this disclosure using conventional chemistry well known to those skilled in the art.

Scheme 1 shows a general scheme for the synthesis of compound 13 where A is CN, and B, X 1 , X 2 , X 3 , X 4 , D and E are as defined for General Formula I, and the synthesis of compound 13a where A is CN, D is as defined for General Formula I provided that the D ring is coupled to the ring defined by X 1 , X 2 , X 3 and X 4 through a ring nitrogen atom in the D ring, X 1 , X 2 , X 3 , X 4 are as defined for Formula I provided that at least one of X 1 and X 2 is nitrogen, and B, X 3 , X 4 , and E is as defined for General Formula I.

Compound 2 is obtained by treating MSH reagent with 3-bromo-5-methoxypyridine, which is commercially available. The aminating reagent O-mesitylsulfonylhydroxylamine (MSH) may be prepared as described in Mendiola, J., et al., Org. Process Res. Dev. 2009, 13(2), 263-267. Compound 2 may be reacted with ethyl propiolate to provide the pyrazolo[1,5-a]pyridine a mixture of compounds 3A and 3B, which typically are obtained in a ratio of approximately 2:1 to 9:1. The mixture of compounds 3A and 3B may be treated with 48% HBr at elevated temperatures, followed by recrystallization or chromatography purifications to isolate compound 4A as the minor isomer and compound 4B as the major isomer.

The isolated compound 4B may be functionalized with a formyl group using POCl 3 followed by purification to provide compound 5. The formyl group of compound 5 may be converted to an oxime group using NH 2 OH to provide compound 6. The oxime group of compound 6 may be converted to a nitrile group using acetic anhydride to provide compound 7. The B group may be installed by treating compound 7 with a corresponding boronic ester having the formula hetAr 1 —B(OR a )(OR b ) where hetAr 1 is as defined for General Formula I and R a and R b are H or C1-C6 alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with one to four C1-C3 alkyl groups, using appropriate palladium-catalyzed cross-coupling reaction conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd 2 (dba) 3 , X-Phos and Na 2 CO 3 in dioxane at elevated temperatures) to provide compound 8 where B is hetAr 1 as defined for General Formula I. The methoxy group of compound 8 may be converted to a hydroxy group by treating compound 8 with aluminum trichloride to provide compound 9. The free hydroxy group of compound 9 may be converted to a triflate group by treating compound 9 with a triflating reagent, for example 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide to provide compound 10. Compound 12 may be prepared by coupling compound 10 with the corresponding boronic ester compound 11 where Z is —B(OR a )(OR b ) and R a and R b are H or C1-C6 alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with one to four C1-C3 alkyl groups, using appropriate palladium-catalyzed cross-coupling reaction conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd 2 (dba) 3 , X-Phos and Na 2 CO 3 in dioxane at elevated temperatures), wherein if the D ring of compound 11 comprises an unsubstituted ring nitrogen atom, the nitrogen atom is protected with an appropriate amine protecting group prior to coupling. The protecting group if present on the D ring of compound 12 may be removed under standard conditions (for example, a Boc protecting group may be removed by treating compound 12 under acidic conditions, e.g., using HCl) to provide compound 13 where E is H. Alternatively, the deprotected D ring may be functionalized (i.e., reacted or treated with an appropriate reagent) to introduce the E group under standard conditions such as described below to provide compound 13 where E is as defined for General Formula I except that E is not H.

Alternatively, compound 10 may be coupled with compound 14 using appropriate palladium-catalyzed cross-coupling reaction conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd(PPh 3 ) 4 and Na 2 CO 3 ) to provide compound 15. Compound 15 may be reacted with compound 16 under appropriate S N Ar conditions (for example, optionally in the presence of a base such as K 2 CO 3 and at elevated temperature) to provide compound 12a, wherein if the D ring of compound 16 comprises a second unsubstituted ring nitrogen atom, the second nitrogen atom is protected with an appropriate amine protecting group prior to coupling. The protecting group if present on the D ring of compound 12a may be removed under standard conditions (for example, a Boc group may be removed by treating compound 12a to acidic conditions, e.g., HCl) to provide compound 13a where E is H. Alternatively, the deprotected D ring may be functionalized (i.e., reacted or treated with an appropriate reagent) to introduce the E group under standard conditions such as described below to provide compound 13a where E is as defined for General Formula I except that E is not H.

Scheme 2 shows an alternative route for the synthesis of compound 13, wherein A is CN, and B, X 1 , X 2 , X 3 , X 4 , D and E are as defined for General Formula I. Compound 4A (prepared as in Scheme 1) may be functionalized with a formyl group using POCl 3 to provide compound 17. The formyl group may be converted to an oxime group using NH 2 OH to provide compound 18. The oxime group may be converted to a nitrile group using acetic anhydride to provide compound 19. The methoxy group of compound 19 may be converted to a hydroxy group by treating compound 19 with aluminum trichloride to provide compound 20. Compound 21 may be prepared by coupling compound 20 with the corresponding boronic ester compound 11 where Z is —B(OR a )(OR b ) and R a and R b are H or C1-C6 alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with one to four C1-C3 alkyl groups, using appropriate palladium-catalyzed cross-coupling reaction conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd(PPh 3 ) 4 and Na 2 CO 3 in dioxane at elevated temperatures), wherein if the D ring of compound 11 comprises an unsubstituted ring nitrogen atom, the nitrogen atom is protected with an appropriate amine protecting group prior to coupling. The free hydroxy group of compound 21 may be converted to a triflate group by treating compound 21 with a triflating reagent, for example 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide to provide compound 22. The B group may be installed by treating compound 22 with the corresponding boronic ester having the formula hetAr 1 —B(OR a )(OR b ) where hetAr 1 is as defined for General Formula I and R a and R b are H or C1-C6 alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with one to four C1-C3 alkyl groups, using appropriate palladium-catalyzed cross-coupling reaction conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd 2 (dba) 3 , X-Phos and Na 2 CO 3 in dioxane at elevated temperatures) to provide compound 12 where B is hetAr 1 as defined for General Formula I. The protecting group if present on the D ring of compound 12 may be removed under standard conditions (for example, a Boc group may be removed by treating compound 12 to acidic conditions, e.g., HCl in propan-2-ol) to provide compound 13 where E is H. Alternatively, the deprotected D ring may be functionalized (i.e., reacted or treated with an appropriate reagent) to introduce the E group under standard conditions such as described below to provide compound 13 where E is as defined for General Formula I except that E is not H.

Scheme 3 shows a general scheme for the synthesis of compound 28 where A is Cl, and B, X 1 , X 2 , X 3 , X 4 , D and E are as defined for General Formula I. Compound 4B (prepared as in Scheme 1) may be chlorinated using N-chlorosuccinimide to provide compound 23. The B group may be installed by coupling compound 23 with an appropriate boronic ester having the formula hetAr 1 —B(OR a )(OR b ) where hetAr 1 is as defined for General Formula I and R a and R b are H or C1-C6 alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with one to four C1-C3 alkyl groups, under appropriate palladium-catalyzed cross-coupling reaction conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd(PPh 3 ) 4 and Na 2 CO 3 in dioxane at elevated temperatures) to provide compound 24 where B is hetAr 1 as defined for General Formula I. The methoxy group of compound 24 may be converted to a hydroxy group under standard conditions, for example by treating compound 24 with BBr 3 , to yield compound 25. The free hydroxy group of compound 25 may be converted to a triflate group by treating compound 25 with an appropriate triflating reagent in the presence of a base, e.g., 1,1,1-trifluoro-N-phenyl-N-((trifluoromethyl)sulfonyl)methanesulfonamide and DIEA to provide compound 26. Compound 27 may be prepared by coupling compound 26 with the corresponding boronic ester compound 11 where Z is —B(OR a )(OR b ) and R a and R b are H or C1-C6 alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with one to four C1-C3 alkyl groups, using under standard coupling conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd(PPh 3 ) 4 and Na 2 CO 3 in dioxane at elevated temperatures), wherein if the D ring of compound 11 comprises an unsubstituted ring nitrogen atom, the nitrogen atom is protected with an appropriate amine protecting group prior to coupling. The protecting group if present on the D ring of compound 27 may be removed under standard conditions (for example, a Boc group may be removed by treating compound 27 with acid (e.g., 5-6 N HCl in propan-2-ol) to provide compound 28 where E is H. Alternatively, the deprotected D ring may be functionalized (i.e., reacted or treated with an appropriate reagent) to introduce the E group under standard conditions such as described below to provide compound 28 where E is as defined for General Formula I except that E is not H.

Scheme 4 shows a general scheme for the synthesis of compound 33, wherein A is H, and B, X 1 , X 2 , X 3 , X 4 , D and E are as defined for General Formula I. Compound 4B (prepared as in Scheme 1) may be coupled with an appropriate boronic ester having the formula hetAr 1 —B(OR a )(OR b ) where hetAr 1 is as defined for General Formula I and R a and R b are H or C1-C6 alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with one to four C1-C3 alkyl groups, under appropriate palladium-catalyzed cross-coupling reaction conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd(PPh 3 ) 4 and Na 2 CO 3 in dioxane at elevated temperatures) to install the B group to provide compound 29 where B is hetAr 1 as defined for General Formula I. The methoxy group of compound 29 may be converted to a hydroxy group by treating compound 29 with aluminum trichloride to provide compound 30. The free hydroxy group of compound 30 may be converted to a triflate group by treating compound 33 with a triflating reagent in the presence of a base, e.g., 1,1,1-trifluoro-N-phenyl-N-((trifluoromethyl)sulfonyl)methanesulfonamide and DIEA in an appropriate solvent such as THF to provide compound 31. Compound 32 may be prepared by coupling compound 31 with compound 11 under appropriate palladium-catalyzed cross-coupling reaction conditions, e.g., Suzuki coupling reaction conditions (for example, a palladium catalyst and optionally a ligand in the presence of an inorganic base, for example, Pd(PPh 3 ) 4 and Na 2 CO 3 in dioxane at elevated temperatures), wherein if the D ring of compound 11 comprises an unsubstituted ring nitrogen atom, the nitrogen atom is protected with an appropriate amine protecting group prior to coupling. The protecting group if present on the D ring of compound 32 may be removed under standard conditions (for example, a Boc group may be removed by treating compound 32 under acidic conditions, e.g., HCl in propan-2-ol) to provide compound 33 where E is H. Alternatively, the deprotected D ring may be functionalized (i.e., reacted or treated with an appropriate reagent) to introduce the E group under standard conditions such as described below to provide compound 33 where E is as defined for General Formula I except that E is not H.

The D ring of any one of compounds 13, 13a, 28, and 33 described in Schemes 1-4 may be functionalized (i.e., reacted or treated with an appropriate reagent) to introduce an E group, where E is any of the E groups defined for General Formula I with the exception of hydrogen, using standard chemistry well known to persons skilled in the art. As used herein, the term “functionalized” refers to a process step in which a compound of Formula I where E is hydrogen is reacted or treated with an appropriate reagent to provide a compound of Formula I where E is other than hydrogen.

For example, an amide derivative (e.g., where D is hetCyc 1 where hetCyc 1 is piperazinyl and E is (C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros; (hydroxy C1-C6 alkyl)C(═O)— optionally substituted with one to three fluoros; (C1-C6 alkoxy)(C1-C6 alkyl)C(═O)—; Cyc 1 C(═O)—; Cyc 1 (C1-C6 alkyl)C(═O)—; hetCyc 4 (C1-C3 alkyl)C(═O)—; Ar 2 C(═O)—; Ar 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H and C1-C6 alkyl or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O; hetAr 2 C(═O)—; or hetAr 2 (C1-C3 alkyl)C(═O)— wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl) or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O, may be obtained by treating compound 13 having a deprotected amino D ring with an carboxylic acid (e.g., with an acid having the formula (C1-C6 alkyl)C(═O)OH optionally substituted with one to three fluoros; (hydroxy C1-C6 alkyl)C(═O)OH optionally substituted with one to three fluoros; (C1-C6 alkoxy)(C1-C6 alkyl)C(═O)OH; Cyc 1 C(═O)OH; Cyc 1 (C1-C6 alkyl)C(═O)OH; hetCyc 4 (C1-C3 alkyl)C(═O)OH; Ar 2 C(═O)OH; Ar 2 (C1-C3 alkyl)C(═O)OH wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H and C1-C6 alkyl or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O; hetAr 2 C(═O)OH; or hetAr 2 (C1-C3 alkyl)C(═O)OH wherein the alkyl portion is optionally substituted with one or two groups independently selected from the group consisting of OH, C1-C6 alkyl, hydroxyC1-C6 alkyl, C1-C6 alkoxy and R e R f N—, where R e and R f are independently H or C1-C6 alkyl) or R e and R f together with the nitrogen to which they are attached form a 5-6 membered azacyclic ring optionally having an additional ring heteroatom selected from N and O) using conventional amide bond formation conditions, for example by treating the carboxylic acid with an activating agent (e.g., HATU), followed by addition of the compound 13 having a deprotected amino D ring in the presence of a base (e.g., an amine base such as DIEA) in an appropriate solvent (such as DMA) to provide a functionalized compound 13. The same chemistry may be utilized with compounds 13a, 28 and 33 to prepare functionalized compounds 13a, 28 and 33, respectively.

As another example, a urea derivative (e.g., where D is hetCyc 1 where hetCyc 1 is piperazinyl and E is hetCyc 4 C(═O)— or R 1 R 2 NC(═O)—) may be prepared by first activating a ring nitrogen in the D ring of compound 13 with triphosgene in the presence of DIEA and in a solvent such as DCM, followed by addition of a primary or secondary amine reagent (e.g., a reagent having the formula hetCyc 4 NH 2 or R 1 R 2 NH) to provide a functionalized compound 13. The same chemistry may be utilized with compounds 13a, 28 and 33 to prepare functionalized compounds 13a, 28 and 33, respectively.

As another example, an N-alkyl derivative (e.g., where D is hetCyc 1 where hetCyc 1 is piperazinyl and E is hydroxyC1-C6 alkyl optionally substituted with one to three fluoros; (C1-C6 alkoxy)hydroxy C1-C6 alkyl; Ar 2 C1-C6 alkyl; (Ar 2 )hydroxy C2-C6 alkyl; or (hetAr 2 )hydroxyC2-C6 alkyl, may be prepared by treating compound 13 where E is H with an alkyl bromide or alkyl chloride (e.g., hydroxyC1-C6 alkyl-X optionally substituted with one to three fluoros; (C1-C6 alkoxy)hydroxy C1-C6 alkyl-X; Ar 2 C1-C6 alkyl-X; (Ar 2 )hydroxy C2-C6 alkyl-X; or (hetAr 2 )hydroxyC2-C6 alkyl-X where X is Br or Cl) or an epoxide in the presence of a base such as DIEA in a solvent at ambient or elevated temperatures) to provide a functionalized compound 13. The same chemistry may be utilized with compounds 13a, 28 and 33 to prepare functionalized compounds 13a, 28 and 33, respectively.

As another example, a compound of Formula I wherein D is hetCyc 1 (where hetCyc 1 is a 4-6 membered heterocyclic ring having 2 ring nitrogen atoms, wherein the heterocyclic ring is optionally substituted with one or more substituents independently selected from the group consisting of C1-C3 alkyl, fluoroC1-C3 alkyl, difluoroC1-C3 alkyl, trifluoroC1-C3 alkyl and OH, or said heterocyclic ring is substituted with a C3-C6 cycloalkylidene ring, or said heterocyclic ring is substituted with an oxo group) and E is Ar 2 C1-C6 alkyl, hetAr 2 C1-C6 alkyl, (hetCyc 4 )C1-C6 alkyl, or (C3-C6 cycloalkoxy)C1-C6 alkyl, may be prepared by treating compound 13 where E is H (wherein E is on a ring nitrogen atom of hetCyc 1 ) with an appropriate aldehyde having the formula Ar 2 (C1-C5 alkyl)C(═O)H, hetAr 2 (C1-C5 alkyl)C(═O)H, (hetCyc 4 )(C1-C5 alkyl)C(═O)H, or (C3-C6 cycloalkoxy)(C1-C5 alkyl)C(═O)H under standard reductive amination reaction conditions, for example in the presence of a base and a reducing agent, for example in the presence of a reducing agent such as sodium triacetoxyborohydride or sodium cyanoborohydride.

As another example, a sulfonamide derivative may be prepared by treating compound 13 where E is H with an appropriate sulfonyl chloride in the presence of a base, such as an amine base (such as triethylamine) in an appropriate solvent to provide a functionalized compound 13. The same chemistry may be utilized with compounds 13a, 28 and 33 to prepare functionalized compounds 13a, 28 and 33, respectively.

Further provided herein is a process for preparing of a compound of General Formula I or a pharmaceutically acceptable salt thereof as defined herein which comprises:

(a) for a compound of General Formula I where E is H and A, B, X 1 , X 2 , X 3 , X 4 , and D are as defined for General Formula I, coupling a corresponding compound having the formula

where A and B are as defined for General Formula I, with a corresponding compound having the formula 11

in the presence of a palladium catalyst and optionally a ligand and in the presence of a base, where Z is —B(OR a )(OR b ) and R a and R b are H or (1-6C)alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with 1-4 substituents selected from (C1-C3 alkyl), the

ring is as defined for hetCyc 1 , hetCyc 2 and hetCyc 3 of Formula I, and X 1 , X 2 , X 3 and X 4 are as defined for General Formula I, followed by removal of a protecting group on the D ring if present; or

(b) for a compound of General Formula I where A, B, X 1 , X 2 , X 3 , X 4 , D and E are as defined for General Formula I with the exception that E is not hydrogen, functionalizing a corresponding compound having the formula

wherein the

moiety is as defined for hetCyc 1 , hetCyc 2 and hetCyc 3 of Formula I, and A, B, X 1 , X 2 , X 3 and X 4 are as defined for General Formula I; or

(c) for a compound of General Formula I where A is CN, D is as defined for General Formula I provided that the D ring is coupled to the ring defined by X 1 , X 2 , X 3 and X 4 through a ring nitrogen atom in the D ring, X 1 , X 2 , X 3 , X 4 are as defined for Formula I provided that at least one of X 1 and X 2 is nitrogen, and E is as defined for General Formula I, reacting a corresponding compound having the formula 15

where B, X 1 , X 2 , X 3 and X 4 are as defined for General Formula I provided that at least one of X 1 and X 2 is nitrogen, with a corresponding compound having the formula 17

in the presence of a base, wherein the

ring is as defined for hetCyc 1 , hetCyc 2 and hetCyc 3 of Formula I; or

(d) for a compound of General Formula I where A is CN, E is H, and B, X 1 , X 2 , X 3 , X 4 , and D are as defined for General Formula I, reacting a compound having the formula 22

where X 1 , X 2 , X 3 , X 4 and D are as defined for General Formula I, with a corresponding boronic ester having the formula

where hetAr 1 is as defined for General Formula I and R a and R b are H or CC6 alkyl, or R a and R b together with the atoms to which they are connected form a 5-6 membered ring optionally substituted with one to four C1-C3 alkyl substituents, in the presence of a palladium catalyst and optionally a ligand and in the presence of a base; and

removing any protecting groups and optionally forming a pharmaceutically acceptable salt thereof.

Referring to processes (a) and (d), suitable palladium catalysts include Pd(PPh 3 ) 4 , Pd 2 (dba) 3 , Pd(OAc) 2 , and Pd(PPh 3 ) 2 C12. Suitable ligands include X-PHOS (2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl), DIPHOS (1,2-Bis(diphenylphosphino)ethane) or rac-BINAP (racemic-2,2′-Bis(diphenylphosphino)-1,1′-binaphthyl). The base may be, for example, an alkali metal carbonate, hydroxide, alkoxide or acetate, such as for example cesium carbonate, sodium carbonate, potassium carbonate, sodium hydroxide, sodium tert-butoxide or potassium acetate. Convenient solvents include aprotic solvents such as ethers (for example tetrahydrofuran or p-dioxane), toluene, DMF or DME. The reaction can be conveniently performed at a temperature ranging from ambient temperature to 120° C., for example from 80 to 110° C.

The ability of test compounds to act as RET inhibitors may be demonstrated by the assay described in Example A. IC 50 's are shown in Table 5.

Compounds of General Formula I have been found to be inhibitors of a RET kinase, and are useful for treating diseases and disorders which can be treated with a RET kinase inhibitor, such as RET-associated diseases and disorders, e.g., proliferative disorders such as cancers, including hematological cancers and solid tumors, and gastrointestinal disorders such as IBS.

As used herein, terms “treat” or “treatment” refer to therapeutic or palliative measures. Beneficial or desired clinical results include, but are not limited to, alleviation, in whole or in part, of symptoms associated with a disease or disorder or condition, diminishment of the extent of disease, stabilized (i.e., not worsening) state of disease, delay or slowing of disease progression, amelioration or palliation of the disease state (e.g., one or more symptoms of the disease), and remission (whether partial or total), whether detectable or undetectable. “Treatment” can also mean prolonging survival as compared to expected survival if not receiving treatment.

As used herein, the term “subject,” “individual,” or “patient,” used interchangeably, refers to any animal, including mammals such as mice, rats, other rodents, rabbits, dogs, cats, swine, cattle, sheep, horses, primates, and humans. In some embodiments, the patient is a human. In some embodiments, the subject has experienced and/or exhibited at least one symptom of the disease or disorder to be treated and/or prevented. In some embodiments, the subject has been identified or diagnosed as having a cancer with dysregulation of a RET gene, a RET protein, or expression or activity, or level of any of the same (a RET-associated cancer) (e.g., as determined using a regulatory agency-approved, e.g., FDA-approved, assay or kit). In some embodiments, the subject has a tumor that is positive for dysregulation of a RET gene, a RET protein, or expression or activity, or level of any of the same (e.g., as determined using a regulatory agency-approved assay or kit). The subject can be a subject with a tumor(s) that is positive for dysregulation of a RET gene, a RET protein, or expression or activity, or level of any of the same (e.g., identified as positive using a regulatory agency-approved, e.g., FDA-approved, assay or kit). The subject can be a subject whose tumors have dysregulation of a RET gene, a RET protein, or expression or activity, or a level of the same (e.g., where the tumor is identified as such using a regulatory agency-approved, e.g., FDA-approved, kit or assay). In some embodiments, the subject is suspected of having a RET-associated cancer. In some embodiments, the subject has a clinical record indicating that the subject has a tumor that has dysregulation of a RET gene, a RET protein, or expression or activity, or level of any of the same (and optionally the clinical record indicates that the subject should be treated with any of the compositions provided herein). In some embodiments, the patient is a pediatric patient.

The term “pediatric patient” as used herein refers to a patient under the age of 21 years at the time of diagnosis or treatment. The term “pediatric” can be further be divided into various subpopulations including: neonates (from birth through the first month of life); infants (1 month up to two years of age); children (two years of age up to 12 years of age); and adolescents (12 years of age through 21 years of age (up to, but not including, the twenty-second birthday)). Berhman R E, Kliegman R, Arvin A M, Nelson W E. Nelson Textbook of Pediatrics, 15th Ed. Philadelphia: W.B. Saunders Company, 1996; Rudolph A M, et al. Rudolph's Pediatrics, 21st Ed. New York: McGraw-Hill, 2002; and Avery M D, First L R. Pediatric Medicine, 2nd Ed. Baltimore: Williams & Wilkins; 1994. In some embodiments, a pediatric patient is from birth through the first 28 days of life, from 29 days of age to less than two years of age, from two years of age to less than 12 years of age, or 12 years of age through 21 years of age (up to, but not including, the twenty-second birthday). In some embodiments, a pediatric patient is from birth through the first 28 days of life, from 29 days of age to less than 1 year of age, from one month of age to less than four months of age, from three months of age to less than seven months of age, from six months of age to less than 1 year of age, from 1 year of age to less than 2 years of age, from 2 years of age to less than 3 years of age, from 2 years of age to less than seven years of age, from 3 years of age to less than 5 years of age, from 5 years of age to less than 10 years of age, from 6 years of age to less than 13 years of age, from 10 years of age to less than 15 years of age, or from 15 years of age to less than 22 years of age.

In certain embodiments, compounds of General Formula I are useful for preventing diseases and disorders as defined herein (for example, autoimmune diseases, inflammatory diseases, and cancer). The term “preventing” as used herein means the prevention of the onset, recurrence or spread, in whole or in part, of the disease or condition as described herein, or a symptom thereof.

The term “RET-associated disease or disorder” as used herein refers to diseases or disorders associated with or having a dysregulation of a RET gene, a RET kinase (also called herein RET kinase protein or RET kinase), or the expression or activity or level of any (e.g., one or more) of the same (e.g., any of the types of dysregulation of a RET gene, a RET kinase, a RET kinase domain, or the expression or activity or level of any of the same described herein). Non-limiting examples of a RET-associated disease or disorder include, for example, cancer and gastrointestinal disorders such as irritable bowel syndrome (IBS).

The term “RET-associated cancer” as used herein refers to cancers associated with or having a dysregulation of a RET gene, a RET kinase (also called herein RET kinase protein or RET kinase), or expression or activity, or level of any of the same. Non-limiting examples of a RET-associated cancer are described herein.

The phrase “dysregulation of a RET gene, a RET kinase, or the expression or activity or level of any of the same” refers to a genetic mutation (e.g., a RET gene translocation that results in the expression of a fusion protein, a deletion in a RET gene that results in the expression of a RET protein that includes a deletion of at least one amino acid as compared to the wild-type RET protein, or a mutation in a RET gene that results in the expression of a RET protein with one or more point mutations, or an alternative spliced version of a RET mRNA that results in a RET protein that results in the deletion of at least one amino acid in the RET protein as compared to the wild-type RET protein), or a RET gene amplification that results in overexpression of a RET protein or an autocrine activity resulting from the overexpression of a RET gene a cell, that results in a pathogenic increase in the activity of a kinase domain of a RET protein (e.g., a constitutively active kinase domain of a RET protein) in a cell. As another example, a dysregulation of a RET gene, a RET protein, or expression or activity, or level of any of the same, can be a mutation in a RET gene that encodes a RET protein that is constitutively active or has increased activity as compared to a protein encoded by a RET gene that does not include the mutation. For example, a dysregulation of a RET gene, a RET protein, or expression or activity, or level of any of the same, can be the result of a gene or chromosome translocation which results in the expression of a fusion protein that contains a first portion of RET that includes a functional kinase domain, and a second portion of a partner protein (i.e., that is not RET). In some examples, dysregulation of a RET gene, a RET protein, or expression or activity, can be a result of a gene translation of one RET gene with another RET gene. Non-limiting examples of fusion proteins are described in Table 1. Non-limiting examples of RET kinase protein point mutations/insertions are described in Table 2. Additional examples of RET kinase protein point mutations are RET inhibitor resistance mutations. Non-limiting examples of RET inhibitor resistance mutations are described in Tables 3 and 4.

The term “wildtype” or “wild-type” describes a nucleic acid (e.g., a RET gene or a RET mRNA) or protein (e.g., a RET protein) that is found in a subject that does not have a RET-associated disease, e.g., a RET-associated cancer (and optionally also does not have an increased risk of developing a RET-associated disease and/or is not suspected of having a RET-associated disease), or is found in a cell or tissue from a subject that does not have a RET-associated disease, e.g., a RET-associated cancer (and optionally also does not have an increased risk of developing a RET-associated disease and/or is not suspected of having a RET-associated disease).

The term “regulatory agency” refers to a country's agency for the approval of the medical use of pharmaceutical agents with the country. For example, a non-limiting example of a regulatory agency is the U.S. Food and Drug Administration (FDA).

Provided herein is a method of treating cancer (e.g., a RET-associated cancer) in a patient in need of such treatment, the method comprising administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof.

In some embodiments of any of the methods or uses described herein, the cancer (e.g., RET-associated cancer) is a hematological cancer. In some embodiments of any of the methods or uses described herein, the cancer (e.g., RET-associated cancer) is a solid tumor. In some embodiments of any of the methods or uses described herein, the cancer (e.g., RET-associated cancer) is lung cancer (e.g., small cell lung carcinoma or non-small cell lung carcinoma), papillary thyroid cancer, medullary thyroid cancer, differentiated thyroid cancer, recurrent thyroid cancer, refractory differentiated thyroid cancer, lung adenocarcinoma, bronchioles lung cell carcinoma, multiple endocrine neoplasia type 2A or 2B (MEN2A or MEN2B, respectively), pheochromocytoma, parathyroid hyperplasia, breast cancer, colorectal cancer (e.g., metastatic colorectal cancer), papillary renal cell carcinoma, ganglioneuromatosis of the gastroenteric mucosa, inflammatory myofibroblastic tumor, or cervical cancer. In some embodiments of any of the methods or uses described herein, the cancer (e.g., RET-associated cancer) is selected from the group of: acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), cancer in adolescents, adrenocortical carcinoma, anal cancer, appendix cancer, astrocytoma, atypical teratoid/rhabdoid tumor, basal cell carcinoma, bile duct cancer, bladder cancer, bone cancer, brain stem glioma, brain tumor, breast cancer, bronchial tumor, Burkitt lymphoma, carcinoid tumor, unknown primary carcinoma, cardiac tumors, cervical cancer, childhood cancers, chordoma, chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), chronic myeloproliferative neoplasms, colon cancer, colorectal cancer, craniopharyngioma, cutaneous T-cell lymphoma, bile duct cancer, ductal carcinoma in situ, embryonal tumors, endometrial cancer, ependymoma, esophageal cancer, esthesioneuroblastoma, Ewing sarcoma, extracranial germ cell tumor, extragonadal germ cell tumor, extrahepatic bile duct cancer, eye cancer, fallopian tube cancer, fibrous histiocytoma of bone, gallbladder cancer, gastric cancer, gastrointestinal carcinoid tumor, gastrointestinal stromal tumors (GIST), germ cell tumor, gestational trophoblastic disease, glioma, hairy cell tumor, hairy cell leukemia, head and neck cancer, heart cancer, hepatocellular cancer, histiocytosis, Hodgkin's lymphoma, hypopharyngeal cancer, intraocular melanoma, islet cell tumors, pancreatic neuroendocrine tumors, Kaposi sarcoma, kidney cancer, Langerhans cell histiocytosis, laryngeal cancer, leukemia, lip and oral cavity cancer, liver cancer, lung cancer, lymphoma, macroglobulinemia, malignant fibrous histiocytoma of bone, osteocarcinoma, melanoma, Merkel cell carcinoma, mesothelioma, metastatic squamous neck cancer, midline tract carcinoma, mouth cancer, multiple endocrine neoplasia syndromes, multiple myeloma, mycosis fungoides, myelodysplastic syndromes, myelodysplastic/myeloproliferative neoplasms, myelogenous leukemia, myeloid leukemia, multiple myeloma, myeloproliferative neoplasms, nasal cavity and paranasal sinus cancer, nasopharyngeal cancer, neuroblastoma, non-Hodgkin's lymphoma, non-small cell lung cancer, oral cancer, oral cavity cancer, lip cancer, oropharyngeal cancer, osteosarcoma, ovarian cancer, pancreatic cancer, papillomatosis, paraganglioma, paranasal sinus and nasal cavity cancer, parathyroid cancer, penile cancer, pharyngeal cancer, pheochromosytoma, pituitary cancer, plasma cell neoplasm, pleuropulmonary blastoma, pregnancy and breast cancer, primary central nervous system lymphoma, primary peritoneal cancer, prostate cancer, rectal cancer, renal cell cancer, retinoblastoma, rhabdomyosarcoma, salivary gland cancer, sarcoma, Sezary syndrome, skin cancer, small cell lung cancer, small intestine cancer, soft tissue sarcoma, squamous cell carcinoma, squamous neck cancer, stomach cancer, T-cell lymphoma, testicular cancer, throat cancer, thymoma and thymic carcinoma, thyroid cancer, transitional cell cancer of the renal pelvis and ureter, unknown primary carcinoma, urethral cancer, uterine cancer, uterine sarcoma, vaginal cancer, vulvar cancer, and Wilms' tumor.

In some embodiments, a hematological cancer (e.g., hematological cancers that are RET-associated cancers) is selected from the group consisting of leukemias, lymphomas (non-Hodgkin's lymphoma), Hodgkin's disease (also called Hodgkin's lymphoma), and myeloma, for instance, acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), acute promyelocytic leukemia (APL), chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), chronic myelomonocytic leukemia (CMML), chronic neutrophilic leukemia (CNL), acute undifferentiated leukemia (AUL), anaplastic large-cell lymphoma (ALCL), prolymphocytic leukemia (PML), juvenile myelomonocyctic leukemia (JMML), adult T-cell ALL, AML with trilineage myelodysplasia (AML/TMDS), mixed lineage leukemia (MLL), myelodysplastic syndromes (MDSs), myeloproliferative disorders (MPD), and multiple myeloma (MM). Additional examples of hematological cancers include myeloproliferative disorders (MPD) such as polycythemia vera (PV), essential thrombocytopenia (ET) and idiopathic primary myelofibrosis (IMF/IPF/PMF). In one embodiment, the hematological cancer (e.g., the hematological cancer that is a RET-associated cancer) is AML or CMML.

In some embodiments, the cancer (e.g., the RET-associated cancer) is a solid tumor. Examples of solid tumors (e.g., solid tumors that are RET-associated cancers) include, for example, thyroid cancer (e.g., papillary thyroid carcinoma, medullary thyroid carcinoma), lung cancer (e.g., lung adenocarcinoma, small-cell lung carcinoma), pancreatic cancer, pancreatic ductal carcinoma, breast cancer, colon cancer, colorectal cancer, prostate cancer, renal cell carcinoma, head and neck tumors, neuroblastoma, and melanoma. See, for example, Nature Reviews Cancer, 2014, 14, 173-186.

In some embodiments, the cancer is selected from the group consisting of lung cancer, papillary thyroid cancer, medullary thyroid cancer, differentiated thyroid cancer, recurrent thyroid cancer, refractory differentiated thyroid cancer, multiple endocrine neoplasia type 2A or 2B (MEN2A or MEN2B, respectively), pheochromocytoma, parathyroid hyperplasia, breast cancer, colorectal cancer, papillary renal cell carcinoma, ganglioneuromatosis of the gastroenteric mucosa, and cervical cancer.

In some embodiments, the patient is a human.

Compounds of General Formula I and pharmaceutically acceptable salts and solvates thereof are also useful for treating a RET-associated cancer.

Accordingly, also provided herein is a method for treating a patient diagnosed with or identified as having a RET-associated cancer, e.g., any of the exemplary RET-associated cancers disclosed herein, comprising administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition thereof as defined herein.

Dysregulation of a RET kinase, a RET gene, or the expression or activity or level of any (e.g., one or more) of the same can contribute to tumorigenesis. For example, a dysregulation of a RET kinase, a RET gene, or expression or activity or level of any of the same can be a translocation, overexpression, activation, amplification, or mutation of a RET kinase, a RET gene, or a RET kinase domain. Translocation can include translocations involving the RET kinase domain, mutations can include mutations involving the RET ligand-binding site, and amplification can be of a RET gene. Other dysregulations can include RET mRNA splice variants and RET autocrine/paracrine signaling, which can also contribute to tumorigenesis.

In some embodiments, the dysregulation in a RET gene, a RET kinase, or expression or activity or level of any of the same, includes overexpression of wild-type RET kinase (e.g., leading to autocrine activation). In some embodiments, the dysregulation in a RET gene, a RET kinase protein, or expression or activity or level of any of the same, includes overexpression, activation, amplification, or mutation in a chromosomal segment comprising the RET gene or a portion thereof, including for example the kinase domain portion, or a portion capable of exhibiting kinase activity.

In some embodiments, the dysregulation of a RET gene, a RET kinase protein, or expression or activity or level of any of the same, includes one or more chromosome translocations or inversions resulting in a RET gene fusions. In some embodiments, the dysregulation of a RET gene, a RET kinase protein, or expression or activity or level of any of the same, is a result of genetic translocations in which the expressed protein is a fusion protein containing residues from a non-RET partner protein, and includes a minimum of a functional RET kinase domain.

Non-limiting examples of RET fusion proteins are shown in Table 1.

In some embodiments, the dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, includes one or more deletions (e.g., deletion of an amino acid at position 4), insertions, or point mutation(s) in a RET kinase. In some embodiments, the dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, includes a deletion of one or more residues from the RET kinase, resulting in constitutive activity of the RET kinase domain.

In some embodiments, the dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, includes at least one point mutation in a RET gene that results in the production of a RET kinase that has one or more amino acid substitutions as compared to the wild-type RET kinase (see, for example, the missense point mutations listed in Table 2).

In some embodiments, the dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, includes a splice variation in a RET mRNA which results in an expressed protein that is an alternatively spliced variant of RET having at least one residue deleted (as compared to the wild-type RET kinase) resulting in a constitutive activity of a RET kinase domain.

In some embodiments, the dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, includes at least one point mutation in a RET gene that results in the production of a RET kinase that has one or more amino acid substitutions or insertions or deletions in a RET gene that results in the production of a RET kinase that has one or more amino acids inserted or removed, as compared to the wild-type RET kinase, which is more resistant to inhibition of its phosphotransferase activity by one or more RET kinase inhibitor(s) that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as compared to a wildtype RET kinase or a RET kinase not including the same mutation. Such mutations can, optionally, not cause a cancer cell or a tumor to decrease its sensitivity to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof (e.g., as compared to a cancer cell or a tumor that does not include the particular RET inhibitor resistance mutation). In such embodiments, a RET inhibitor resistance mutation can result in a RET kinase that has one or more of an increased V max , a decreased K m for ATP, and an increased K D for a RET kinase inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, when in the presence of a RET kinase inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as compared to a wildtype RET kinase or a RET kinase not having the same mutation in the presence of the same RET kinase inhibitor.

In other embodiments, the dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, includes at least one point mutation in a RET gene that results in the production of a RET kinase that has one or more amino acid substitutions as compared to the wild-type RET kinase, and which has increased resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as compared to a wildtype RET kinase or a RET kinase not including the same mutation. In such embodiments, a RET inhibitor resistance mutation can result in a RET kinase that has one or more of an increased V max , a decreased K m , and a decreased K D in the presence of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, as compared to a wildtype RET kinase or a RET kinase not having the same mutation in the presence of the same compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof.

Examples of RET inhibitor resistance mutations can, e.g., include point mutations, insertions, or deletions in and near the ATP binding site in the tertiary structure of RET kinase, including but not limited to the gatekeeper residue, P-loop residues, residues in or near the DFG motif, and ATP cleft solvent front amino acid residues. Additional examples of these types of mutations include changes in residues that may affect enzyme activity and/or drug binding including but are not limited to residues in the activation loop, residues near or interacting with the activation loop, residues contributing to active or inactive enzyme conformations, changes including mutations, deletions, and insertions in the loop proceeding the C-helix and in the C-helix. Specific residues or residue regions that may be changed (and are RET inhibitor resistance mutations) include but are not limited to those listed in Table 3 based on the human wildtype RET protein sequence (e.g., SEQ ID NO: 1). Additional examples of RET inhibitor resistance mutation positions are shown in Table 4. Changes to these residues may include single or multiple amino acid changes, insertions within or flanking the sequences, and deletions within or flanking the sequences.

In some embodiments, compounds of General Formula I and pharmaceutically acceptable salts and solvates are useful in treating patients that develop cancers with RET inhibitor resistance mutations (that result in an increased resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E) by either dosing in combination or as a follow-up therapy to existing drug treatments (e.g., other RET kinase inhibitors that are not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). Exemplary RET kinase inhibitors (e.g., other RET kinase inhibitors that are not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof) are described herein. In some embodiments, a RET kinase inhibitor can be selected from the group consisting of cabozantinib, vandetanib, alectinib, sorafenib, levatinib, ponatinib, dovitinib, sunitinib, foretinib, BLU667, and BLU6864.

In some embodiments, compounds of the General Formula I and pharmaceutically acceptable salts and solvates would be useful for treating a cancer that has been identified as having one or more RET inhibitor resistance mutations (that result in an increased resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E).

The oncogenic role of RET was firstly described in papillary thyroid carcinoma (PTC) (Grieco et al., Cell, 1990, 60, 557-63), which arises from follicular thyroid cells and is the most common thyroid malignancy. Approximately 20-30% of PTC harbor somatic chromosomal rearrangements (translocations or inversions) linking the promoter and the 5′ portions of constitutively expressed, unrelated genes to the RET tyrosine kinase domain (Greco et al., Q. J. Nucl. Med. Mol. Imaging, 2009, 53, 440-54), therefore driving its ectopic expression in thyroid cells. To date, a variety of fusion partners have been identified, all providing a protein/protein interaction domain that induces ligand-independent RET dimerization and constitutive kinase activity (see, e.g., Table 1). The role of RET-PTC rearrangements in the pathogenesis of PTC has been confirmed in transgenic mice (Santoro et al., Oncogene, 1996, 12, 1821-6). Recently, a 10.6 Mb pericentric inversion in chromosome 10, where RET gene maps, has been identified in about 2% of lung adenocarcinoma patients, generating different variants of the chimeric gene KIF5B-RET (Ju et al., Genome Res., 2012, 22, 436-45; Kohno et al., 2012 , Nature Med., 18, 375-7; Takeuchi et al., Nature Med., 2012, 18, 378-81; Lipson et al., 2012 , Nature Med., 18, 382-4). The fusion transcripts are highly expressed and all the resulting chimeric proteins contain the N— terminal portion of the coiled-coil region of KIF5B, which mediates homodimerization, and the entire RET kinase domain. None of RET positive patients harbor other known oncogenic alterations (such as EGFR or K-Ras mutation, ALK translocation), supporting the possibility that KIF5B-RET fusion could be a driver mutation of lung adenocarcinoma. The oncogenic potential of KIF5B-RET has been confirmed by transfecting the fusion gene into cultured cell lines: similarly to what has been observed with RET-PTC fusion proteins, KIF5B-RET is constitutively phosphorylated and induces NIH-3T3 transformation and IL-3 independent growth of BA-F3 cells. However, other RET fusion proteins have been identified in lung adenocarcinoma patients, such as the CCDC6-RET fusion protein, which has been found to play a key role in the proliferation of the human lung adenocarcinoma cell line LC-2/ad ( Journal of Thoracic Oncology, 2012, 7(12): 1872-1876). RET inhibitors have been shown to be useful in treating lung cancers involving RET rearrangements (Drilon, A. E. et al. J Clin Oncol 33, 2015 (suppl; abstr 8007)). RET fusion proteins have also been identified in patients having colorectal cancer (Song Eun-Kee, et al. International Journal of Cancer, 2015, 136: 1967-1975).

Besides rearrangements of the RET sequence, gain of function point mutations of RET proto-oncogene are also driving oncogenic events, as shown in medullary thyroid carcinoma (MTC), which arises from parafollicular calcitonin-producing cells (de Groot, et al., Endocrine Rev., 2006, 27, 535-60; Wells and Santoro, Clin. Cancer Res., 2009, 15, 7119-7122). Around 25% of MTC are associated with multiple endocrine neoplasia type 2 (MEN2), a group of inherited cancer syndromes affecting neuroendocrine organs caused by germline activating point mutations of RET. In MEN2 subtypes (MEN2A, MEN2B and Familial MTC/FMTC) RET gene mutations have a strong phenotype-genotype correlation defining different MTC aggressiveness and clinical manifestations of the disease. In MEN2A syndrome mutations involve one of the six cysteine residues (mainly C634) located in the cysteine-rich extracellular region, leading to ligand-independent homodimerization and constitutive RET activation. Patients develop MTC at a young age (onset at 5-25 years) and may also develop pheochromocytoma (50%) and hyperparathyroidism. MEN2B is mainly caused by M918T mutation, which is located in the kinase domain. This mutation constitutively activates RET in its monomeric state and alters substrate recognition by the kinase. MEN2B syndrome is characterized by an early onset (<1 year) and very aggressive form of MTC, pheochromocytoma (50% of patients) and ganglioneuromas. In FMTC the only disease manifestation is MTC, usually occurring at an adult age. Many different mutations have been detected, spanning the entire RET gene. The remaining 75% of MTC cases are sporadic and about 50% of them harbor RET somatic mutations: the most frequent mutation is M918T that, as in MEN2B, is associated with the most aggressive phenotype. Somatic point mutations of RET have also been described in other tumors such as colorectal cancer (Wood et al., Science, 2007, 318, 1108-13) and small cell lung carcinoma ( Jpn. J. Cancer Res., 1995, 86, 1127-30).

RET signaling components have been found to be expressed in primary breast tumors and to functionally interact with estrogen receptor-cc pathway in breast tumor cell lines (Boulay et al., Cancer Res. 2008, 68, 3743-51; Plaza-Menacho et al., Oncogene, 2010, 29, 4648-57), while RET expression and activation by GDNF family ligands could play an important role in perineural invasion by different types of cancer cells (Ito et al., Surgery, 2005, 138, 788-94; Gil et al., J. Natl. Cancer Inst., 2010, 102, 107-18; Iwahashi et al., Cancer, 2002, 94, 167-74).

RET is also expressed in 30-70% of invasive breast cancers, with expression being relatively more frequent in estrogen receptor-positive tumors (Plaza-Menacho, I., et al., Oncogene, 2010, 29, 4648-4657; Esseghir, S., et al., Cancer Res., 2007, 67, 11732-11741; Morandi, A., et al., Cancer Res., 2013, 73, 3783-3795; Gattelli, A., EMBO Mol. Med., 2013, 5, 1335-1350).

The identification of RET rearrangements has been reported in a subset of (patient-derived xenograft) PDX established from colorectal cancer. Although the frequency of such event in colorectal cancer patients remains to be defined, these data suggest a role of RET as a target in this indication (Gozgit et al., AACR Annual Meeting 2014). Studies have shown that the RET promoter is frequently methylated in colorectal cancers, and heterozygous missense mutations, which are predicted to reduce RET expression, are identified in 5-10% of cases, which suggests that RET might have some features of a tumor suppressor in sporadic colon cancers (Luo, Y., et al., Oncogene, 2013, 32, 2037-2047; Sjoblom, T., et al., Science, 2006, 268-274; Cancer Genome Atlas Network, Nature, 2012, 487, 330-337).

An increasing number of tumor types are now being shown to express substantial levels of wild-type RET kinase that could have implications for tumor progression and spread. RET is expressed in 50-65% of pancreatic ductal carcinomas, and expression is more frequent in metastatic and higher grade tumors (Ito, Y, et al., Surgery, 2005, 138, 788-794; Zeng, Q., et al., J. Int. Med. Res. 2008, 36, 656-664).

In neoplasms of hematopoietic lineages, RET is expressed in acute myeloid leukemia (AML) with monocytic differentiation, as well as in CMML (Gattei, V. et al., Blood, 1997, 89, 2925-2937; Gattei, V., et al., Ann. Hematol, 1998, 77, 207-210; Camos, M., Cancer Res. 2006, 66, 6947-6954). Recent studies have identified rare chromosomal rearrangements that involve RET in patients with chronic myelomonocytic leukemia (CMML). CMML is frequently associated with rearrangements of several tyrosine kinases, which result in the expression of chimeric cytosolic oncoproteins that lead to activation of RAS pathways (Kohlmann, A., et al., J. Clin. Oncol. 2010, 28, 2858-2865). In the case of RET, gene fusions that link RET with BCR (BCR-RET) or with fibroblast growth factor receptor 1 oncogene partner (FGFR1OP-RET) were transforming in early hematopoietic progenitor cells and could shift maturation of these cells towards monocytic paths, probably through the initiation of RET-mediated RAS signaling (Ballerini, P., et al., Leukemia, 2012, 26, 2384-2389).

RET expression has also been shown to occur in several other tumor types, including prostate cancer, small-cell lung carcinoma, melanoma, renal cell carcinoma, and head and neck tumors (Narita, N., et al., Oncogene, 2009, 28, 3058-3068; Mulligan, L. M., et al., Genes Chromosomes Cancer, 1998, 21, 326-332; Flavin, R., et al., Urol. Oncol., 2012, 30, 900-905; Dawson, D. M., J Natl Cancer Inst, 1998, 90, 519-523).

In neuroblastoma, RET expression and activation by GFLs has roles in tumor cell differentiation, potentially collaborating with other neurotrophic factor receptors to down regulate N-Myc, the expression of which is a marker of poor prognosis (Hofstra, R. M., W., et al., Hum. Genet. 1996, 97, 362-364; Petersen, S. and Bogenmann, E., Oncogene, 2004, 23, 213-225; Brodeur, G. M., Nature Ref. Cancer, 2003, 3, 203-216).

Multitargeted inhibitors which cross react with RET are known (Borrello, M. G., et al., Expert Opin. Ther. Targets, 2013, 17(4), 403-419; International Patent Application Nos. WO 2014/141187, WO 2014/184069, and WO 2015/079251).

Accordingly, provided herein are methods for treating a patient diagnosed with (or identified as having) a cancer (e.g., a RET-associated cancer) (e.g., a RET-associated cancer that includes one or more RET inhibitor resistance mutations) that include administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. Also provided herein are methods for treating a patient identified or diagnosed as having a RET-associated cancer (e.g., a patient that has been identified or diagnosed as having a RET-associated cancer through the use of a regulatory agency-approved, e.g., FDA-approved test or assay for identifying dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, in a patient or a biopsy sample from the patient) (e.g., any of the RET-associated cancers described herein or known in the art) (e.g., a RET-associated cancer that includes one or more RET inhibitor resistance mutations) that include administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof. In some embodiments, the test or assay is provided as a kit.

Also provided are methods for treating cancer in a patient in need thereof, the method comprising: (a) determining if the cancer in the patient is a RET-associated cancer (e.g., a RET-associated cancer including RET-associated cancers having one or more RET inhibitor resistance mutations) (e.g., using a regulatory-agency approved, e.g., FDA-approved, kit for identifying dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, in a patient or a biopsy sample from the patient, or by performing any of the non-limiting examples of assays described herein); and (b) if the cancer is determined to be a RET-associated cancer, administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof. Some embodiments of these methods further include administering to the subject another anticancer agent (e.g., another RET inhibitor, e.g., a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a different RET inhibitor that is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). In some embodiments, the subject was previously treated with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or previously treated with another anticancer treatment, e.g., after resection of a tumor or radiation therapy.

Also provided are methods of treating a patient (e.g., a patient suspected of having a RET-associated cancer, a patient presenting with one or more symptoms of a RET-associated cancer, or a patient having an elevated risk of developing a RET-associated cancer) that include performing an assay (e.g., an assay that utilizes next generation sequencing, pyrosequencing, immunohistochemistry, or break apart FISH analysis) (e.g., using a regulatory agency-approved, e.g., FDA-approved kit) on a sample obtained from the patient to determine whether the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations), and administering (e.g., specifically or selectively administering) a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof to the patient determined to have dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same. Additional, non-limiting assays that may be used in these methods are described herein. Additional assays are also known in the art. Some embodiments of these methods further include administering to the subject another anticancer agent (e.g., another RET inhibitor, e.g., a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a different RET inhibitor that is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). In some embodiments of these methods, the subject was previously treated with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or previously treated with another anticancer treatment, e.g., after resection of a tumor or radiation therapy.

Also provided is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof for use in treating a RET-associated cancer (e.g., a RET-associated cancer including RET-associated cancers having one or more RET inhibitor resistance mutations) in a patient identified or diagnosed as having a RET-associated cancer through a step of performing an assay (e.g., an in vitro assay) (e.g., an assay that utilizes next generation sequencing, immunohistochemistry, or break apart FISH analysis) (e.g., using a regulatory agency-approved, e.g., FDA-approved kit) on a sample obtained from the patient to determine whether the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations), where the presence of dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, identifies that the patient has a RET-associated cancer. Also provided is the use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof for the manufacture of a medicament for treating a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations) in a patient identified or diagnosed as having a RET-associated cancer through a step of performing an assay (e.g., an in vitro assay) (e.g., an assay that utilizes next generation sequencing, immunohistochemistry, or break apart FISH analysis) (e.g., using a regulatory agency-approved, e.g., FDA-approved, kit) on a sample obtained from the patient to determine whether the patient has a dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same where the presence of dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, identifies that the patient has a RET-associated cancer. Some embodiments of any of the methods or uses described herein further include recording in the patient's clinical record (e.g., a computer readable medium) that the patient determined to have dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., determined to have one or more RET inhibitor resistance mutations), through the performance of the assay, should be administered a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof.

Also provided is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, for use in the treatment of a cancer (e.g., a RET-associated cancer, e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations) in a patient in need thereof or a patient identified or diagnosed as having a RET-associated cancer (e.g., a patient that has been identified or diagnosed as having a RET-associated cancer through the use of a regulatory agency-approved, e.g., FDA-approved, kit for identifying dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, in a patient or a biopsy sample from the sample) (e.g., any of the RET-associated cancers described herein or known in the art). Also provided is the use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof for the manufacture of a medicament for treating a cancer (e.g., a RET-associated cancer, e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations) in a patient identified or diagnosed as having a RET-associated cancer (e.g., a patient that has been identified or diagnosed as having a RET-associated cancer through the use of a regulatory agency-approved, e.g., FDA-approved, kit for identifying dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, in a patient or a biopsy sample from the patient) (e.g., any of the RET-associated cancers described herein or known in the art).

In some embodiments of any of the methods or uses described herein, the patient has been identified or diagnosed as having a cancer with dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., a cancer having one or more RET inhibitor resistance mutations) (e.g., as determined using a regulatory agency-approved, e.g., FDA-approved, assay or kit). In some embodiments of any of the methods or uses described herein, the patient has a tumor that is positive for dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., a tumor positive for one or more RET inhibitor resistance mutations) (e.g., as determined using a regulatory-agency-approved assay or kit). In some embodiments of any of the methods or uses described herein, the patient can be a patient with a tumor(s) that is positive for dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., a tumor that is positive for one or more RET inhibitor resistance mutations) (e.g., identified as positive using a regulatory agency-approved, e.g., FDA-approved, assay or kit). In some embodiments of any of the methods or uses described herein, the patient can be a patient whose tumors have dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., a patient whose tumors have one or more RET inhibitor resistance mutations) (e.g., where the tumor is identified as such using a regulatory agency-approved, e.g., FDA-approved, kit or assay). In some embodiments of any of the methods or uses described herein, the patient is suspected of having a RET-associated cancer. In some embodiments of any of the methods or uses described herein, the patient has a clinical record indicating that the patient has a tumor that has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., a tumor having one or more RET inhibitor resistance mutations) (and optionally the clinical record indicates that the patient should be treated with any of the compounds of General Formula I or a pharmaceutically acceptable salts or solvates thereof or compositions provided herein).

Also provided are methods of treating a patient that include administering a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof to a patient having a clinical record that indicates that the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations). Also provided is the use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof for the manufacture of a medicament for treating a RET-associated cancer in a patient having a clinical record that indicates that the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations). Also provided is the use of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof for treating a RET-associated cancer in a patient having a clinical record that indicates that the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations). Some embodiments of these methods and uses can further include: a step of performing an assay (e.g., an in vitro assay) (e.g., an assay that utilizes next generation sequencing, immunohistochemistry, or break apart FISH analysis) (e.g., using a regulatory agency-approved, e.g., FDA-approved, kit) on a sample obtained from the patient to determine whether the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, and recording the information in a patient's clinical file (e.g., a computer readable medium) that the patient has been identified to have dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations).

Also provided herein is a method of treating a subject. The method includes performing an assay on a sample obtained from the subject to determine whether the subject has dysregulation of a RET gene, a RET protein, or expression or level of any of the same (e.g., one or more RET inhibitor resistance mutations). The method also includes administering to a subject determined to have dysregulation of a RET gene, a RET protein, or expression or activity, or level of any of the same (e.g., one or more RET inhibitor resistance mutations) a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. In some embodiments, the RET fusion can be selected from a KIF5B-RET fusion and a CCDC6-RET fusion. In some embodiments, the dysregulation in a RET gene, a RET kinase protein, or expression or activity of the same is a gene or chromosome translocation that results in the expression of a RET fusion protein (e.g., any of the RET fusion proteins described herein). In some embodiments, the dysregulation in a RET gene, a RET kinase protein, or expression or activity or level of any of the same is one or more point mutation in the RET gene (e.g., any of the one or more of the RET point mutations described herein). The one or more point mutations in a RET gene can result, e.g., in the translation of a RET protein having one or more of the following amino acid substitutions: M918T, M918V, C634W, V804L, and V804M. In some embodiments, the dysregulation in a RET gene, a RET kinase protein, or expression or activity or level of any of the same is one or more RET inhibitor resistance mutations (e.g., any combination of the one or more RET inhibitor resistance mutations described herein). Some embodiments of these methods further include administering to the subject another anticancer agent (e.g., another RET inhibitor, e.g., a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a different RET inhibitor that is a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof).

Also provided are methods (e.g., in vitro methods) of selecting a treatment for a patient that includes administration of a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof for a patient identified or diagnosed as having a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations) (e.g., a patient that has been identified or diagnosed as having a RET-associated cancer through the use of a regulatory agency-approved, e.g., FDA-approved, kit for identifying dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, in a patient or a biopsy sample from the patient) (e.g., any of the RET-associated cancers described herein or known in the art). Some embodiments can further include administering the selected treatment to the patient identified or diagnosed as having a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations). Some embodiments can further include administering the selected treatment to the patient identified or diagnosed as having a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations). Some embodiments can further include a step of performing an assay (e.g., an in vitro assay) (e.g., an assay that utilizes the next generation sequencing, immunohistochemistry, or break apart FISH analysis) (e.g., using a regulatory agency-approved, e.g., FDA-approved, kit) on a sample obtained from the patient to determine whether the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations), and identifying and diagnosing a patient determined to have dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations), as having a RET-associated cancer.

Also provided herein are methods of selecting a treatment for a patient that include administration of a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, wherein the methods include a step of performing an assay (e.g., an in vitro assay) (e.g., an assay that utilizes next generation sequencing, immunohistochemistry, or break apart FISH analysis) (e.g., using a regulatory agency-approved, e.g., FDA-approved, kit) on a sample obtained from the patient to determine whether the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations), and identifying or diagnosing a patient determined to have dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations), as having a RET-associated cancer, and selecting a therapeutic treatment including administration of a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof to the patient identified or diagnosed as having a RET-associated cancer. Some embodiments further include administering the selected treatment to the patient identified or diagnosed as having a RET-associated cancer.

Also provided are methods of selecting a patient for treatment including administration of a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof, wherein the methods include selecting, identifying, or diagnosing a patient having a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations), and selecting the patient for treatment including administration of a therapeutically-effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. In some embodiments, identifying or diagnosing a patient as having a RET-associated cancer can include a step of performing an assay (e.g., an in vitro assay) (e.g., an assay that utilizes next generation sequencing, immunohistochemistry, or break apart FISH analysis) (e.g., using a regulatory agency-approved, e.g., FDA-approved, kit) on a sample obtained from the patient to determine whether the patient has dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations), and identifying or diagnosing a patient determined to have dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, as having a RET-associated cancer. In some embodiments, the method of selecting a treatment can be used as a part of a clinical study that includes administration of various treatments of a RET-associated cancer.

In some embodiments of any of the methods or uses described herein, an assay used to determine whether the patient has dysregulation of a RET gene, or a RET kinase, or expression or activity or level of any of the same (e.g., one or more RET inhibitor resistance mutations), using a sample (e.g., a biological sample or a biopsy sample (e.g., a paraffin-embedded biopsy sample) from a patient (e.g., a patient suspected of having a RET-associated cancer, a patient having one or more symptoms of a RET-associated cancer, and/or a patient that has an increased risk of developing a RET-associated cancer) can include, for example, next generation sequencing, immunohistochemistry, fluorescence microscopy, break apart FISH analysis, Southern blotting, Western blotting, FACS analysis, Northern blotting, and PCR-based amplification (e.g., RT-PCR and quantitative real-time RT-PCR). As is well-known in the art, the assays are typically performed, e.g., with at least one labelled nucleic acid probe or at least one labelled antibody or antigen-binding fragment thereof. Assays can utilize other detection methods known in the art for detecting dysregulation of a RET gene, a RET kinase, or expression or activity or levels of any of the same (see, e.g., the references cited herein).

In the field of medical oncology it is normal practice to use a combination of different forms of treatment to treat each patient with cancer. In medical oncology the other component(s) of such conjoint treatment or therapy in addition to compositions provided herein may be, for example, surgery, radiotherapy, and chemotherapeutic agents, such as kinase inhibitors, signal transduction inhibitors and/or monoclonal antibodies. Compounds of General Formula I therefore may also be useful as adjuvants to cancer treatment, that is, they can be used in combination with one or more additional therapies or therapeutic agents, for example a chemotherapeutic agent that works by the same or by a different mechanism of action.

In some embodiments of any the methods described herein, the compound of General Formula I (or a pharmaceutically acceptable salt or solvate thereof) is administered in combination with a therapeutically effective amount of at least one additional therapeutic agent selected from one or more additional therapies or therapeutic (e.g., chemotherapeutic) agents.

Non-limiting examples of additional therapeutic agents include: other RET-targeted therapeutic agents (i.e. other RET kinase inhibitors; RET inhibitors that are not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof), receptor tyrosine kinase-targeted therapeutic agents, signal transduction pathway inhibitors, checkpoint inhibitors, modulators of the apoptosis pathway (e.g. obataclax); cytotoxic chemotherapeutics, angiogenesis-targeted therapies, immune-targeted agents, and radiotherapy.

In some embodiments, the other RET-targeted therapeutic is a multikinase inhibitor exhibiting RET inhibition activity. In some embodiments, the other RET-targeted therapeutic inhibitor is selective for a RET kinase. Exemplary RET-targeted therapeutics can exhibit inhibition activity (IC 50 ) against a RET kinase of less than about 1000 nM, less than about 500 nM, less than about 200 nM, less than about 100 nM, less than about 50 nM, less than about 25 nM, less than about 10 nM, or less than about 1 nM.

Non-limiting examples of RET-targeted therapeutic agents include alectinib, apatinib, cabozantinib (XL-184), dovitinib, lenvatinib, motesanib, nintedanib, ponatinib, regorafenib, sitravatinib (MGCD516), sunitinib, sorafenib, vatalanib, vandetanib, AUY-922 (5-(2,4-Dihydroxy-5-isopropyl-phenyl)-N-ethyl-4-[4-(morpholinomethyl)phenyl]isoxazole-3-carboxamide), BLU6864, BLU-667, DCC-2157, NVP-AST487 (1-[4-[(4-ethylpiperazin-1-yl)methyl]-3-(trifluoromethyl)phenyl]-3-[4-[6-(methylamino)pyrimidin-4-yl]oxyphenyl]urea), PZ-1, RPI-1 (1,3-dihydro-5,6-dimethoxy-3-[(4-hydroxyphenyl)methylene]-H-indol-2-one), RXDX-105 (1-(3-((6,7-dimethoxyquinazolin-4-yl)oxy)phenyl)-3-(5-(1,1,1-trifluoro-2-methylpropan-2-yl)isoxazol-3-yl)urea), SPP86 (1-Isopropyl-3-(phenylethynyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine), and TG101209 (N-(1,1-dimethylethyl)-3-[[5-methyl-2-[[4-(4-methyl-1-piperazinyl)phenyl]amino]-4-pyrimidinyl]amino]-benzenesulfonamide).

Additional examples of other RET kinase inhibitors include those described in U.S. Pat. Nos. 9,150,517 and 9,149,464, and International Publication No. WO 2014075035, all of which are hereby incorporated by reference. For example, in some embodiments the other RET inhibitor is a compound of formula I:

wherein R 1 is C 6 -C 24 alkyl or polyethylene glycol; or a pharmaceutically acceptable alt form thereof. In some embodiments, the other RET inhibitor is 4-{5-[bis-(chloroethyl)-amino]-1-methyl-1H-benzimidazol-2-yl}butyric acid dodecyl ester.

Yet other therapeutic agents include RET inhibitors such as those described, for example, in U.S. Pat. Nos. 7,504,509; 8,299,057; 8,399,442; 8,067,434; 8,937,071; 9,006,256; and 9,035,063; U.S. Publication Nos. 2014/0121239; 20160176865; 2011/0053934; 2011/0301157; 2010/0324065; 2009/0227556; 2009/0130229; 2009/0099167; 2005/0209195; International Publication Nos. WO 2014/184069; WO 2014/072220; WO 2012/053606; WO 2009/017838; WO 2008/031551; WO 2007/136103; WO 2007/087245; WO 2007/057399; WO 2005/051366; WO 2005/062795; and WO 2005/044835; and J. Med. Chem. 2012, 55 (10), 4872-4876, all of which are hereby incorporated by reference in their entireties.

Non-limiting examples of receptor tyrosine kinase (Trk) targeted therapeutic agents, include afatinib, cabozantinib, cetuximab, crizotinib, dabrafenib, entrectinib, erlotinib, gefitinib, imatinib, lapatinib, lestaurtinib, nilotinib, pazopanib, panitumumab, pertuzumab, sunitinib, trastuzumab, 1-((3 S,4R)-4-(3-fluorophenyl)-1-(2-methoxyethyl)pyrrolidin-3-yl)-3-(4-methyl-3-(2-methylpyrimidin-5-yl)-1-phenyl-1H-pyrazol-5-yl)urea, AG 879, AR-772, AR-786, AR-256, AR-618, AZ-23, AZ623, DS-6051, Gö 6976, GNF-5837, GTx-186, GW 441756, LOXO-101, MGCD516, PLX7486, RXDX101, TPX-0005, and TSR-011. Additional Trk targeted thereapeutic agents include those described in U.S. Pat. Nos. 8,450,322; 8,513,263; 8,933,084; 8,791,123; 8,946,226; 8,450,322; 8,299,057; and 8,912,194; U.S. Publication No. 2016/0137654; 2015/0166564; 2015/0051222; 2015/0283132; and 2015/0306086; International Publication No. WO 2010/033941; WO 2010/048314; WO 2016/077841; WO 2011/146336; WO 2011/006074; WO 2010/033941; WO 2012/158413; WO 2014078454; WO 2014078417; WO 2014078408; WO 2014078378; WO 2014078372; WO 2014078331; WO 2014078328; WO 2014078325; WO 2014078323; WO 2014078322; WO 2015175788; WO 2009/013126; WO 2013/174876; WO 2015/124697; WO 2010/058006; WO 2015/017533; WO 2015/112806; WO 2013/183578; and WO 2013/074518, all of which are hereby incorporated by reference in their entireties.

Further examples of Trk inhibitors can be found in U.S. Pat. No. 8,637,516, International Publication No. WO 2012/034091, U.S. Pat. No. 9,102,671, International Publication No. WO 2012/116217, U.S. Publication No. 2010/0297115, International Publication No. WO 2009/053442, U.S. Pat. No. 8,642,035, International Publication No. WO 2009092049, U.S. Pat. No. 8,691,221, International Publication No. WO2006131952, all of which are incorporated by reference in their entireties herein. Exemplary Trk inhibitors include GNF-4256, described in Cancer Chemother. Pharmacol. 75(1):131-141, 2015; and GNF-5837 (N-[3-[[2,3-dihydro-2-oxo-3-(1H-pyrrol-2-ylmethylene)-1H-indol-6-yl]amino]-4-methylphenyl]-N′-[2-fluoro-5-(trifluoromethyl)phenyl]-urea), described in ACS Med. Chem. Lett. 3(2): 140-145, 2012, each of which is incorporated by reference in its entirety herein.

Additional examples of Trk inhibitors include those disclosed in U.S. Publication No. 2010/0152219, U.S. Pat. No. 8,114,989, and International Publication No. WO 2006/123113, all of which are incorporated by reference in their entireties herein. Exemplary Trk inhibitors include AZ623, described in Cancer 117(6):1321-1391, 2011; AZD6918, described in Cancer Biol. Ther. 16(3):477-483, 2015; AZ64, described in Cancer Chemother . Pharmacol. 70:477-486, 2012; AZ-23 ((S)-5-Chloro-N2-(1-(5-fluoropyridin-2-yl)ethyl)-N4-(5-isopropoxy-1H-pyrazol-3-yl)pyrimidine-2,4-diamine), described in Mol. Cancer Ther. 8:1818-1827, 2009; and AZD7451; each of which is incorporated by reference in its entirety.

A Trk inhibitor can include those described in U.S. Pat. Nos. 7,615,383; 7,384,632; 6,153,189; 6,027,927; 6,025,166; 5,910,574; 5,877,016; and 5,844,092, each of which is incorporated by reference in its entirety.

Further examples of Trk inhibitors include CEP-751, described in Int. J. Cancer 72:672-679, 1997; CT327, described in Acta Derm. Venereol. 95:542-548, 2015; compounds described in International Publication No. WO 2012/034095; compounds described in U.S. Pat. No. 8,673,347 and International Publication No. WO 2007/022999; compounds described in U.S. Pat. No. 8,338,417; compounds described in International Publication No. WO 2016/027754; compounds described in U.S. Pat. No. 9,242,977; compounds described in U.S. Publication No. 2016/0000783; sunitinib (N-(2-diethylaminoethyl)-5-[(Z)-(5-fluoro-2-oxo-1H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide), as described in PLoS One 9:e95628, 2014; compounds described in International Publication No. WO 2011/133637; compounds described in U.S. Pat. No. 8,637,256; compounds described in Expert. Opin. Ther. Pat. 24(7):731-744, 2014; compounds described in Expert Opin. Ther. Pat. 19(3):305-319, 2009; (R)-2-phenylpyrrolidine substituted imadizopyridazines, e.g., (4-((5-chloro-4-(methylamino)-7H-pyrrolo[2,3-d]pyrimidin-2-yl)amino)-3-methoxyphenyl)(morpholino)methanone as described in ACS Med. Chem. Lett. 6(5):562-567, 2015 ; GTx -186 and others, as described in PLoS One 8(12):e83380, 2013; K 252 a ((9S-(9α,10β,12α))-2,3,9,10,11,12-hexahydro-10-hydroxy-10-(methoxycarbonyl)-9-methyl-9,12-epoxy-1H-diindolo[1,2,3-fg:3′,2′,1′-kl]pyrrolo[3,4-i][1,6]benzodiazocin-1-one), as described in Mol. Cell Biochem. 339(1-2):201-213, 2010; 4-aminopyrazolylpyrimidines, e.g., AZ-23 (((S)-5-chloro-N2-(1-(5-fluoropyridin-2-yl)ethyl)-N4-(5-isopropoxy-1H-pyrazol-3-yl)pyrimidine-2,4-diamine)), as described in J. Med. Chem. 51(15):4672-4684, 2008; PHA-739358 (danusertib), as described in Mol. Cancer Ther. 6:3158, 2007; Gö 6976 (5,6,7,13-tetrahydro-13-methyl-5-oxo-12H-indolo[2,3-a]pyrrolo[3,4-c]carbazole-12-propanenitrile), as described in J. Neurochem. 72:919-924, 1999; GW441756 ((3Z)-3-[(1-methylindol-3-yl)methylidene]-1H-pyrrolo[3,2-b]pyridin-2-one), as described in IJAE 115:117, 2010; milciclib (PHA-848125AC), described in J. Carcinog. 12:22, 2013; AG-879 ((2E)-3-[3,5-Bis(1,1-dimethylethyl)-4-hydroxyphenyl]-2-cyano-2-propenethioamide); altiratinib (N-(4-((2-(cyclopropanecarboxamido)pyridin-4-yl)oxy)-2,5-difluorophenyl)-N-(4-fluorophenyl)cyclopropane-1,1-dicarboxamide); cabozantinib (N-(4-((6,7-Dimethoxyquinolin-4-yl)oxy)phenyl)-N′-(4-fluorophenyl)cyclopropane-1,1-dicarboxamide); lestaurtinib ((5S,6S,8R)-6-Hydroxy-6-(hydroxymethyl)-5-methyl-7,8,14,15-tetrahydro-5H-16-oxa-4b,8a, 14-triaza-5,8-methanodibenzo[b,h]cycloocta[jkl]cyclopenta[e]-as-indacen-13(6H)-one); dovatinib (4-amino-5-fluoro-3-[6-(4-methylpiperazin-1-yl)-1H-benzimidazol-2-yl]quinolin-2(1H)-one mono 2-hydroxypropanoate hydrate); sitravatinib (N-(3-fluoro-4-((2-(5-(((2-methoxyethyl)amino)methyl)pyridin-2-yl)thieno[3,2-b]pyridin-7-yl)oxy)phenyl)-N-(4-fluorophenyl)cyclopropane-1,1-dicarboxamide); ONO-5390556; regorafenib (4-[4-({[4-Chloro-3-(trifluoromethyl)phenyl]carbamoyl}amino)-3-fluorophenoxy]-N-methylpyridine-2-carboxamide hydrate); VSR-902A; all of the references above are incorporated by reference in their entireties herein.

The ability of a Trk inhibitor to act as a TrkA, TrkB, and/or Trk C inhibitor may be tested using the assays described in Examples A and B in U.S. Pat. No. 8,513,263, which is incorporated herein by reference.

In some embodiments, signal transduction pathway inhibitors include Ras-Raf-MEK-ERK pathway inhibitors (e.g., binimetinib, selumetinib, encorafinib, sorafenib, trametinib, and vemurafenib), PI3K-Akt-mTOR-S6K pathway inhibitors (e.g. everolimus, rapamycin, perifosine, temsirolimus), and other kinase inhibitors, such as baricitinib, brigatinib, capmatinib, danusertib, ibrutinib, milciclib, quercetin, regorafenib, ruxolitinib, semaxanib, AP32788, BLU285, BLU554, INCB39110, INCB40093, INCB50465, INCB52793, INCB54828, MGCD265, NMS-088, NMS-1286937, PF 477736 ((R)-amino-N-[5,6-dihydro-2-(1-methyl-1H-pyrazol-4-yl)-6-oxo-1Hpyrrolo[4,3,2-ef][2,3]benzodiazepin-8-yl]-cyclohexaneacetamide), PLX3397, PLX7486, PLX8394, PLX9486, PRN1008, PRN1371, RXDX103, RXDX106, RXDX108, and TG101209 (N-tert-butyl-3-(5-methyl-2-(4-(4-methylpiperazin-1-yl)phenylamino)pyrimidin-4-ylamino)benzenesulfonamide).

Non-limiting examples of checkpoint inhibitors include ipilimumab, tremelimumab, nivolumab, pidilizumab, MPDL3208A, MEDI4736, MSB0010718C, BMS-936559, BMS-956559, BMS-935559 (MDX-1105), AMP-224, and pembrolizumab.

In some embodiments, cytotoxic chemotherapeutics are selected from arsenic trioxide, bleomycin, cabazitaxel, capecitabine, carboplatin, cisplatin, cyclophosphamide, cytarabine, dacarbazine, daunorubicin, docetaxel, doxorubicin, etoposide, fluorouracil, gemcitabine, irinotecan, lomustine, methotrexate, mitomycin C, oxaliplatin, paclitaxel, pemetrexed, temozolomide, and vincristine.

Non-limiting examples of angiogenesis-targeted therapies include aflibercept and bevacizumab.

In some embodiments, immune-targeted agents are selected from aldesleukin, interferon alfa-2b, ipilimumab, lambrolizumab, nivolumab, prednisone, and sipuleucel-T.

Non-limiting examples of radiotherapy include radioiodide therapy, external-beam radiation, and radium 223 therapy.

Additional kinase inhibitors include those described in, for example, U.S. Pat. Nos. 7,514,446; 7,863,289; 8,026,247; 8,501,756; 8,552,002; 8,815,901; 8,912,204; 9,260,437; 9,273,051; U.S. Publication No. US 2015/0018336; International Publication No. WO 2007/002325; WO 2007/002433; WO 2008/080001; WO 2008/079906; WO 2008/079903; WO 2008/079909; WO 2008/080015; WO 2009/012283; WO 2009/143018; WO 2009/143024; WO 2009/152083; WO 2010/111527; WO 2012/109075; WO 2014/194127; WO 2015/112806; WO 2007/110344; WO 2009/071480; WO 2009/118411; WO 2010/031816; WO 2010/145998; WO 2011/092120; WO 2012/101032; WO 2012/139930; WO 2012/143248; WO 2012/152763; WO 2013/014039; WO 2013/102059; WO 2013/050448; WO 2013/050446; WO 2014/019908; WO 2014/072220; WO 2014/184069; and WO 2016/075224 all of which are hereby incorporated by reference in their entireties.

Further examples of kinase inhibitors include those described in, for example, WO 2016/081450; WO 2016/022569; WO 2016/011141; WO 2016/011144; WO 2016/011147; WO 2015/191667; WO 2012/101029; WO 2012/113774; WO 2015/191666; WO 2015/161277; WO 2015/161274; WO 2015/108992; WO 2015/061572; WO 2015/058129; WO 2015/057873; WO 2015/017528; WO/2015/017533; WO 2014/160521; and WO 2014/011900, each of which is hereby incorporated by reference in its entirety.

Accordingly, also provided herein is a method of treating cancer, comprising administering to a patient in need thereof a pharmaceutical combination for treating cancer which comprises (a) a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, (b) an additional therapeutic agent, and (c) optionally at least one pharmaceutically acceptable carrier for simultaneous, separate or sequential use for the treatment of cancer, wherein the amounts of the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof and the additional therapeutic agent are together effective in treating the cancer.

In some embodiments, the additional therapeutic agent(s) includes any one of the above listed therapies or therapeutic agents which are standards of care in cancers wherein the cancer has a dysregulation of a RET gene, a RET protein, or expression or activity, or level of any of the same.

These additional therapeutic agents may be administered with one or more doses of the compound of General Formula I, or a pharmaceutically acceptable salt or solvate thereof, or pharmaceutical composition thereof, as part of the same or separate dosage forms, via the same or different routes of administration, and/or on the same or different administration schedules according to standard pharmaceutical practice known to one skilled in the art.

Also provided herein is (i) a pharmaceutical combination for treating a cancer (e.g., a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations)) in a patient in need thereof, which comprises (a) a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, (b) at least one additional therapeutic agent (e.g., any of the exemplary additional therapeutic agents described herein or known in the art), and (c) optionally at least one pharmaceutically acceptable carrier for simultaneous, separate or sequential use for the treatment of cancer, wherein the amounts of the compound of General Formula I or pharmaceutically acceptable salt or solvate thereof and of the additional therapeutic agent are together effective in treating the cancer; (ii) a pharmaceutical composition comprising such a combination; (iii) the use of such a combination for the preparation of a medicament for the treatment of cancer; and (iv) a commercial package or product comprising such a combination as a combined preparation for simultaneous, separate or sequential use; and to a method of treatment of cancer a patient in need thereof. In one embodiment the patient is a human.

The term “pharmaceutical combination”, as used herein, refers to a pharmaceutical therapy resulting from the mixing or combining of more than one active ingredient and includes both fixed and non-fixed combinations of the active ingredients. The term “fixed combination” means that a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof and at least one additional therapeutic agent (e.g., a chemotherapeutic agent), are both administered to a patient simultaneously in the form of a single composition or dosage. The term “non-fixed combination” means that a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof and at least one additional therapeutic agent (e.g., chemotherapeutic agent) are formulated as separate compositions or dosages such that they may be administered to a patient in need thereof simultaneously, concurrently or sequentially with variable intervening time limits, wherein such administration provides effective levels of the two or more compounds in the body of the patient. These also apply to cocktail therapies, e.g. the administration of three or more active ingredients

Accordingly, also provided herein is a method of treating a cancer (e.g., a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations)), comprising administering to a patient in need thereof a pharmaceutical combination for treating cancer which comprises (a) a compound of General Formula I or pharmaceutically acceptable salt or solvate thereof, (b) an additional therapeutic agent, and (c) optionally at least one pharmaceutically acceptable carrier for simultaneous, separate or sequential use for the treatment of cancer, wherein the amounts of the compound of General Formula I or pharmaceutically acceptable salt or solvate thereof and the additional therapeutic agent are together effective in treating the cancer. In one embodiment, the compound of General Formula I or pharmaceutically acceptable salt or solvate thereof, and the additional therapeutic agent are administered simultaneously as separate dosages. In one embodiment, the compound of General Formula I or pharmaceutically acceptable salt or solvate thereof, and the additional therapeutic agent are administered as separate dosages sequentially in any order, in jointly therapeutically effective amounts, e.g. in daily or intermittently dosages. In one embodiment, compound of General Formula I or pharmaceutically acceptable salt or solvate thereof, and the additional therapeutic agent are administered simultaneously as a combined dosage.

Also provided herein is a method of treating a disease or disorder mediated by RET (e.g., dysregulation of RET gene, a RET kinase, or expression or activity or level of any of the same, e.g., one or more RET inhibitor resistance mutations) in a patient in need of such treatment, the method comprising administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof. A disease or disorder mediated by RET (e.g., dysregulation of RET gene, a RET kinase, or expression or activity or level of any of the same, e.g., one or more RET inhibitor resistance mutations) can include any disease, disorder or condition that is directly or indirectly linked to expression or activity of RET, including overexpression and/or abnormal activity levels. In one embodiment, the disease is cancer (e.g., a RET-associated cancer). In one embodiment, the cancer is any of the cancers or RET-associated cancers described herein.

Although the genetic basis of tumorigenesis may vary between different cancer types, the cellular and molecular mechanisms required for metastasis appear to be similar for all solid tumor types. During a metastatic cascade, the cancer cells lose growth inhibitory response, undergo alterations in adhesiveness and produce enzymes that can degrade extracellular matrix components. This leads to detachment of tumor cells from the original tumor, infiltration into the circulation through newly formed vasculature, migration and extravasation of the tumor cells at favorable distant sites where they may form colonies. A number of genes have been identified as being promoters or suppressors of metastasis. For example, overexpression of glial cell-derived neurotrophic factor (GDNF) and its RET receptor tyrosine kinase have been correlated with cancer proliferation and metastasis. See, e.g., Zeng, Q. et al. J. Int. Med. Res . (2008) 36(4): 656-64.

Accordingly, also provided herein are methods for inhibiting, preventing, aiding in the prevention, or decreasing the symptoms of metastasis of a cancer in a patient in need thereof, the method comprising administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof or a pharmaceutical composition thereof. Such methods can be used in the treatment of one or more of the cancers described herein. See, e.g., US Publication No. 2013/0029925; International Publication No. WO 2014/083567; and U.S. Pat. No. 8,568,998. In some embodiments, the cancer is a RET-associated cancer. In some embodiments, the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof is used in combination with an additional therapy or another therapeutic agent, including a chemotherapeutic agent, such as a kinase inhibitor.

The term “metastasis” is an art known term and means the formation of an additional tumor (e.g., a solid tumor) at a site distant from a primary tumor in a subject or patient, where the additional tumor includes the same or similar cancer cells as the primary tumor.

Also provided are methods of decreasing the risk of developing a metastasis or an additional metastasis in a patient having a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations) that include: selecting, identifying, or diagnosing a patient as having a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations), and administering a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof to the patient selected, identified, or diagnosed as having a RET-associated cancer. Also provided are methods of decreasing the risk of developing a metastasis or an additional metastasis in a patient having a RET-associated cancer (e.g., a RET-associated cancer having one or more RET inhibitor resistance mutations) that includes administering a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvent thereof to a patient having a RET-associated cancer. The decrease in the risk of developing a metastasis or an additional metastasis in a patient having a RET-associated cancer can be compared to the risk of developing a metastasis or an additional metastasis in the patient prior to treatment, or as compared to a patient or a population of patients having a similar or the same RET-associated cancer that has received no treatment or a different treatment.

The phrase “risk of developing a metastasis” means the risk that a subject or patient having a primary tumor will develop an additional tumor (e.g., a solid tumor) at a site distant from a primary tumor in a subject or patient over a set period of time, where the additional tumor includes the same or similar cancer cells as the primary tumor. Methods for reducing the risk of developing a metastasis in a subject or patient having a cancer are described herein.

The phrase “risk of developing additional metastases” means the risk that a subject or patient having a primary tumor and one or more additional tumors at sites distant from the primary tumor (where the one or more additional tumors include the same or similar cancer cells as the primary tumor) will develop one or more further tumors distant from the primary tumor, where the further tumors include the same or similar cancer cells as the primary tumor. Methods for reducing the risk of developing additional metastasis are described herein.

In some embodiments, the presence of one or more RET inhibitor resistance mutations in a tumor causes the tumor to be more resistant to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof (e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). Methods useful when a RET inhibitor resistance mutation causes the tumor to be more resistant to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof are described below. For example, provided herein are methods of treating a subject having a cancer that include: identifying a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and administering to the identified subject a treatment that does not include a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy (e.g., a treatment that includes a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). Also provided are methods of treating a subject identified as having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E) that include administering to the subject a treatment that does not include a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy (e.g., a treatment that includes a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). Also provided are methods of selecting a treatment for a subject having a cancer that include: identifying a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and selecting a treatment that does not include a RET inhibitors that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy for the identified subject (e.g., a treatment that includes a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). Also provided are methods of selecting a treatment for a subject having a cancer that include: selecting a treatment that does not include a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy (e.g., a treatment that includes a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof) for a subject identified as having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). Also provided are methods of selecting a subject having a cancer for a treatment that does not include a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy that include: identifying a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and selecting the identified subject for a treatment that does not include a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy (e.g., a treatment that includes a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). Also provided are methods of selecting a subject having a cancer for a treatment that does not include a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy that include: selecting a subject identified as having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E), for a treatment that does not include a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy (e.g., a treatment that includes a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). Also provided are methods of determining the likelihood that a subject having a cancer will have a positive response to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy that include: determining whether a cancer cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and determining that a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E), has a decreased likelihood of having a positive response to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy. Also provided are methods of determining the likelihood that a subject having cancer will have a positive response to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy that include: determining that a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E), has a decreased likelihood of having a positive response to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy. Also provided are methods of predicting the efficacy of treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy in a subject having cancer that include: determining whether a cancer cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and determining that treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy is less likely to be effective in a subject having a cancer cell in a sample obtained from the subject that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). Also provided are methods of predicting the efficacy of treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy in a subject having cancer that include: determining that treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy is less likely to be effective in a subject having a cancer cell in a sample obtained from the subject that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E).

Also provided are methods of treating a subject having a cancer that include: (a) administering one or more doses of a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, to the subject for a period of time; (b) after (a), determining whether a cancer cell in a sample obtained from the subject has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and (c) administering a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy or in conjunction with another anticancer agent (e.g., any anticancer agent known in the art, e.g., another RET inhibitor, e.g., the same RET inhibitor administered in step (a)) to the subject if the subject has a cancer cell that has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); or (d) administering additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) to the subject if the subject has a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). In some embodiments, where the subject is administered additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a), the subject can also be administered another anticancer agent (e.g., another RET inhibitor, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof).

Also provided are methods of treating a subject having a cancer that include: (a) administering one or more doses of a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, to the subject for a period of time; (b) after (a), determining whether a cancer cell in a sample obtained from the subject has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and (c) administering a different RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof (different from the RET inhibitor administered in (a)) as a monotherapy or in conjunction with another anticancer agent (e.g., any anticancer agent known in the art, e.g., another RET inhibitor, e.g., the same RET inhibitor administered in (a)) to the subject if the subject has a cancer cell that has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); or (d) administering additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) to the subject if the subject has a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). In some embodiments, where the subject is administered additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a), the subject can also be administered another anticancer agent (e.g., another RET inhibitor, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof).

Also provided are methods of treating a subject having a cancer that include: (a) determining whether a cancer cell in a sample obtained from a subject having a cancer and previously administered one or more doses of a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and (c) administering a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy or in conjunction with another anticancer agent (e.g., any anticancer agent known in the art, e.g., another RET inhibitor, e.g., the same RET inhibitor previously administered to the subject) to the subject if the subject has a cancer cell that has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); or (d) administering additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject if the subject has cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). In some embodiments, where the subject is administered additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject, the subject can also be administered another anticancer agent (e.g., another RET inhibitor, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof).

Also provided are methods of treating a subject having a cancer that include: (a) determining whether a cancer cell in a sample obtained from a subject having a cancer and previously administered one or more doses of a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and (b) administering a different RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof (different from the RET inhibitor previously administered to the subject) as a monotherapy or in conjunction with another anticancer agent (e.g., any anticancer agent known in the art, e.g., another RET inhibitor, e.g., the same RET inhibitor previously administered to the subject) to the subject if the subject has a cancer cell that has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); or (d) administering additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject if the subject has cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). In some embodiments, where the subject is administered additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject, the subject can also be administered another anticancer agent (e.g., another RET inhibitor, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof).

Also provided are methods of selecting a treatment for a subject having a cancer that include (a) administering one or more doses of a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof to the subject for a period of time; (b) after (a), determining whether a cancer cell in a sample obtained from the subject has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and (c) selecting a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy or in conjunction with another anticancer agent (e.g., any anticancer agent known in the art, e.g., another RET inhibitor, e.g., the same RET inhibitor administered in step (a)) for the subject if the subject has a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); or (d) selecting additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) for the subject if the subject has a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). In some embodiments, when additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) are selected for the subject, the method can further include selecting doses of another anticancer agent (e.g., another RET inhibitor, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof) for the subject.

Also provided are methods of selecting a treatment for a subject having a cancer that include (a) administering one or more doses of a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof to the subject for a period of time; (b) after (a), determining whether a cancer cell in a sample obtained from the subject has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and (c) selecting a different RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof (different from the RET inhibitor administered to the subject in (a)) as a monotherapy or in conjunction with another anticancer agent (e.g., any anticancer agent known in the art, e.g., another RET inhibitor, e.g., the same RET inhibitor administered to the subject in (a)) for the subject if the subject has a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); or (d) selecting additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) for the subject if the subject has a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a), e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). In some embodiments, when additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) are selected for the subject, the method can further include selecting doses of another anticancer agent (e.g., another RET inhibitor, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof) for the subject.

Also provided are methods of method of selecting a treatment for a subject having a cancer that include (a) determining whether a cancer cell in a sample obtained from a subject having a cancer and previously administered one or more doses of a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); (b) selecting a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy or in conjunction with another anticancer agent (e.g., any anticancer agent known in the art, e.g., another RET inhibitor, e.g., the same RET inhibitor previously administered to the subject) for the subject if the subject has a cancer cell that has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); or (c) selecting additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject if the subject has a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). In some embodiments, when additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate previously administered to the subject are selected for the subject, the method can further include selecting doses of another anticancer agent (e.g., another RET inhibitor, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof) for the subject.

Also provided are methods of method of selecting a treatment for a subject having a cancer that include (a) determining whether a cancer cell in a sample obtained from a subject having a cancer and previously administered one or more doses of a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); (b) selecting a different RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof (different from the RET inhibitor previously administered to the subject) as a monotherapy or in conjunction with another anticancer agent (e.g., any anticancer agent known in the art, e.g., another RET inhibitor, e.g., the same RET inhibitor previously administered to the subject) for the subject if the subject has a cancer cell that has at least one RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); or (c) selecting additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject if the subject has a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E). In some embodiments, when additional doses of the RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate previously administered to the subject are selected for the subject, the method can further include selecting doses of another anticancer agent (e.g., another RET inhibitor, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof) for the subject.

Also provided are methods of determining a subject's risk for developing a cancer that has some resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that include: determining whether a cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and identifying a subject having a cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E), as having an increased likelihood of developing a cancer that has some resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. Also provided are methods of determining a subject's risk for developing a cancer that has some resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that include: identifying a subject having a cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E), as having an increased likelihood of developing a cancer that has some resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. Also provided are methods of determining the presence of a cancer that has some resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that includes: determining whether a cancer cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E); and determining that a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E), has a cancer that has some resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. Also provided are methods of determining the presence of a cancer that has some resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof in a subject that include: determining that a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E), has a cancer that has some resistance to a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof.

In some embodiments of any of the methods described herein, a RET inhibitor resistance mutation that confers increased resistance to a cancer cell or tumor to treatment with a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, can be any of the RET inhibitor resistance mutations listed in Table 3 or 4 (e.g., a substitution at amino acid position 804, e.g., V804M, V804L, or V804E).

In some embodiments, the presence of one or more RET inhibitor resistance mutations in a tumor causes the tumor to be more resistant to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. Methods useful when a RET inhibitor resistance mutation causes the tumor to be more resistant to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof are described below. For example, provided herein are methods of treating a subject having a cancer that include: identifying a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof); and administering to the identified subject a treatment that does not include a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy. Also provided are methods of treating a subject identified as having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof) that include administering to the subject a treatment that does not include a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy. Also provided are methods of selecting a treatment for a subject having a cancer that include: identifying a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof); and selecting a treatment that does not include a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy for the identified subject. Also provided are methods of selecting a treatment for a subject having a cancer that include: selecting a treatment that does not include a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy for a subject identified as having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). Also provided are methods of selecting a subject having a cancer for a treatment that does not include a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy that include: identifying a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof); and selecting the identified subject for a treatment that does not include a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy. Also provided are methods of selecting a subject having a cancer for a treatment that does not include a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy that include: selecting a subject identified as having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof), for a treatment that does not include a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy. Also provided are methods of determining the likelihood that a subject having a cancer will have a positive response to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy that include: determining whether a cancer cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof); and determining that a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof), has a decreased likelihood of having a positive response to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy. Also provided are methods of determining the likelihood that a subject having cancer will have a positive response to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy that include: determining that a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof), has a decreased likelihood of having a positive response to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy. Also provided are methods of predicting the efficacy of treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy in a subject having cancer that include: determining whether a cancer cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof); and determining that treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy is less likely to be effective in a subject having a cancer cell in a sample obtained from the subject that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof). Also provided are methods of predicting the efficacy of treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy in a subject having cancer that include: determining that treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as a monotherapy is less likely to be effective in a subject having a cancer cell in a sample obtained from the subject that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof).

Also provided are methods of treating a subject having a cancer that include: (a) administering one or more doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof for a period of time; (b) after (a), determining whether a cancer cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a)); and (c) administering a different RET inhibitor (e.g., a compound that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that is different from that administered in step (a)) as a monotherapy or in conjunction with another anticancer agent (e.g., any of the RET inhibitors described herein, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., the same compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof administered in (a)) to a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a)); or (d) administering additional doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) to a subject having a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a)). In some embodiments, where the subject is administered additional doses of the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a), the subject can also be administered another anticancer agent (e.g., another RET inhibitor, e.g., a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that is different from the compound of step (a)).

Also provided are methods of treating a subject having a cancer that include: (a) determining whether a cancer cell in a sample obtained from a subject having a cancer and previously administered one or more doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject); (b) administering a different RET inhibitor (e.g., a compound that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that is different from the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject) as a monotherapy or in conjunction with another anticancer agent (e.g., any of the RET inhibitors described herein, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., the same compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject) to a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject); or (c) administering additional doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to a subject having a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject). In some embodiments, where the subject is administered additional doses of the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a), the subject can also be administered another anticancer agent (e.g., another RET inhibitor, e.g., a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that is different from the compound of step (a)).

Also provided are methods of selecting a treatment for a subject having a cancer that include: (a) administering one or more doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof to the subject for a period of time; (b) after (a), determining whether a cancer cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a)); and (c) selecting a different RET inhibitor (e.g., a compound that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that is different from that administered in step (a)) as a monotherapy or in conjunction with another anticancer agent (e.g., any of the RET inhibitors described herein, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., the same compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof administered in (a)) for the subject if the subject has a cancer cell that has a RET inhibitor resistance mutation (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a)); or (d) selecting additional doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) for the subject if the subject has a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of (a)). In some embodiments, where additional doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) are selected for the subject, the method can also include further selecting another anticancer agent (e.g., another RET inhibitor, e.g., a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that is different from the compound of step (a)).

Also provided are methods of selecting a treatment for a subject having a cancer that include: (a) determining whether a cancer cell in a sample obtained from a subject having a cancer and previously administered one or more doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject); (b) selecting a different RET inhibitor (e.g., a compound that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that is different from the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject) as a monotherapy or in conjunction with another anticancer agent (e.g., any of the RET inhibitors described herein, e.g., a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, e.g., the same compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject) for the subject if the subject has a cancer cell that has a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject); or (c) selecting additional doses of the compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof previously administered to the subject if the subject has a cancer cell that does not have a RET inhibitor resistance mutation (that confers increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that was previously administered to the subject). In some embodiments, where additional doses of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof of step (a) are selected for the subject, the method can also include further selecting another anticancer agent (e.g., another RET inhibitor, e.g., a RET inhibitor that is not a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that is different from the compound of step (a)).

Also provided are methods of determining a subject's risk for developing a cancer that has some resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that include: determining whether a cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof); and identifying the subject if the subject has a cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof), as having an increased likelihood of developing a cancer that has some resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. Also provided are methods of determining a subject's risk for developing a cancer that has some resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that include: identifying a subject having a cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof), as having an increased likelihood of developing a cancer that has some resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. Also provided are methods of determining the presence of a cancer that has some resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof that includes: determining whether a cancer cell in a sample obtained from the subject has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof); and determining that a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof), has a cancer that has some resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. Also provided are methods of determining the presence of a cancer that has some resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof in a subject that include: determining that a subject having a cancer cell that has one or more RET inhibitor resistance mutations (that confer increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof), has a cancer that has some resistance to a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof.

In some embodiments of any of the methods described herein, a RET inhibitor resistance mutation that confers increased resistance to a cancer cell or tumor to treatment with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, can be any of the RET inhibitor resistance mutations listed in Table 3 or 4.

Methods of determining the level of resistance of a cancer cell or a tumor to a RET inhibitor (e.g., any of the RET inhibitors described herein or known in the art) can be determined using methods known in the art. For example, the level of resistance of a cancer cell to a RET inhibitor can be assessed by determining the IC 50 of a RET inhibitor (e.g., any of the RET inhibitors described herein or known in the art) on the viability of a cancer cell. In other examples, the level of resistance of a cancer cell to a RET inhibitor can be assessed by determining the growth rate of the cancer cell in the presence of a RET inhibitor (e.g., any of the RET inhibitors described herein). In other examples, the level of resistance of a tumor to a RET inhibitor can be assessed by determining the mass or size of one or more tumors in a subject over time during treatment with a RET inhibitor (e.g., any of the RET inhibitors described herein). In other examples, the level of resistance of a cancer cell or a tumor to a RET inhibitor can be indirectly assessed by determining the activity of a RET kinase including one or more of the RET inhibitor resistance mutations (i.e., the same RET kinase expressed in a cancer cell or a tumor in a subject). The level of resistance of a cancer cell or tumor having one or more RET inhibitor resistance mutations to a RET inhibitor is relative to the level of resistance in a cancer cell or tumor that does not have a RET inhibitor resistance mutation (e.g., a cancer cell or tumor that does not have the same RET inhibitor resistance mutations, a cancer cell or a tumor that does not have any RET inhibitor resistance mutations, or a cancer cell or a tumor that expresses a wildtype RET protein). For example, the determined level of resistance of a cancer cell or a tumor having one or more RET inhibitor resistance mutations can be greater than about 1%, greater than about 2%, greater than about 3%, greater than about 4%, greater than about 5%, greater than about 6%, greater than about 7%, greater than about 8%, greater than about 9%, greater than about 10%, greater than about 11%, greater than about 12%, greater than about 13%, greater than about 14%, greater than about 15%, greater than about 20%, greater than about 25%, greater than about 30%, greater than about 35%, greater than about 40%, greater than about 45%, greater than about 50%, greater than about 60%, greater than about 70%, greater than about 80%, greater than about 90%, greater than about 100%, greater than about 110%, greater than about 120%, greater than about 130%, greater than about 140%, greater than about 150%, greater than about 160%, greater than about 170%, greater than about 180%, greater than about 190%, greater than about 200%, greater than about 210%, greater than about 220%, greater than about 230%, greater than about 240%, greater than about 250%, greater than about 260%, greater than about 270%, greater than about 280%, greater than about 290%, or greater than about 300% of the level of resistance in a cancer cell or tumor that does not have a RET inhibitor resistance mutation (e.g., a cancer cell or tumor that does not have the same RET inhibitor resistance mutations, a cancer cell or a tumor that does not have any RET inhibitor resistance mutations, or a cancer cell or a tumor that expresses a wildtype RET protein).

RET is thought to play an important role in the development and survival of afferent nociceptors in the skin and gut. RET kinase knock-out mice lack enteric neurons and have other nervous system anomalies suggesting that a functional RET kinase protein product is necessary during development (Taraviras, S. et al., Development, 1999, 126:2785-2797). Moreover population studies of patients with Hirschsprung's disease characterized by colonic obstruction due to lack of normal colonic enervation have a higher proportion of both familial and sporadic loss of function RET mutations (Butler Tjaden N., et al., Transl. Res., 2013, 162: 1-15). Irritable bowel syndrome (IBS) is a common illness affecting 10-20% of individuals in developed countries and is characterized by abnormal bowel habits, bloating and visceral hypersensitivity (Camilleri, M., N. Engl. J. Med., 2012, 367: 1626-1635). While the etiology of IBS is unknown it is thought to result from either a disorder between the brain and gastrointestinal tract, a disturbance in the gut microbiome or increased inflammation. The resulting gastrointestinal changes affect normal bowel transit resulting in either diarrhea or constipation. Furthermore in many IBS patients the sensitization of the peripheral nervous system results in visceral hypersensitivity or allodynia (Keszthelyi, D., Eur. J. Pain, 2012, 16: 1444-1454). See, e.g., U.S. Publication No. 2015/0099762.

Accordingly, provided herein are methods for treating a patient diagnosed with (or identified as having) an irritable bowel syndrome (IBS) including diarrhea-predominant, constipation-predominant or alternating stool pattern, functional bloating, functional constipation, functional diarrhea, unspecified functional bowel disorder, functional abdominal pain syndrome, chronic idiopathic constipation, functional esophageal disorders, functional gastroduodenal disorders, functional anorectal pain, and inflammatory bowel disease that include administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof.

Also provided herein are methods for treating a patient identified or diagnosed as having a RET-associated irritable bowel syndrome (IBS) (e.g., a patient that has been identified or diagnosed as having a RET-associated irritable bowel syndrome (IBS) through the use of a regulatory agency-approved, e.g., FDA-approved, kit for identifying dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, in a patient or a biopsy sample from the patient) that include administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof.

Also provided herein are methods for treating pain associated with IBS that include administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof. In some embodiments, a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof is administered in combination with another therapeutic agent useful for treating one or more symptoms of IBS.

Also provided are methods for treating an irritable bowel syndrome (IBS) in a patient in need thereof, the method comprising: (a) determining if the irritable bowel syndrome (IBS) in the patient is a RET-associated IBS (e.g., using a regulatory-agency approved, e.g., FDA-approved, kit for identifying dysregulation of a RET gene, a RET kinase, or expression or activity or level of any of the same, in a patient or a biopsy sample from the patient, or by performing any of the non-limiting examples of assays described herein); and (b) if the IBS is determined to be a RET-associated IBS, administering to the patient a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof.

In some embodiments, the compounds of the present invention are useful for treating irritable bowel syndrome (IBS) in combination with one or more additional therapeutic agents or therapies effective in treating the irritable bowel syndrome that work by the same or a different mechanism of action. The at least one additional therapeutic agent may be administered with a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof as part of the same or separate dosage forms, via the same or different routes of administration, and on the same or different administration schedules according to standard pharmaceutical practice known to one skilled in the art.

Non-limiting examples of additional therapeutics for the treatment of irritable bowel syndrome (IBS) include probiotics, fiber supplements (e.g., psyllium , methylcellulose), anti-diarrheal medications (e.g., loperamide), bile acid binders (e.g., cholestyramine, colestipol, colesevelam), anticholinergic and antispasmodic medications (e.g., hyoscyamine, dicyclomine), antidepressant medications (e.g., tricyclic antidepressant such as imipramine or notriptyline or a selective serotonin reuptake inhibitor (SSRI) such as fluoxetine or paroxetine), antibiotics (e.g., rifaximin), alosetron, and lubiprostone.

Accordingly, also provided herein are methods of treating irritable bowel syndrome (IBS), comprising administering to a patient in need thereof a pharmaceutical combination for treating IBS which comprises (a) a compound of General Formula I or pharmaceutically acceptable salt or solvate thereof, (b) an additional therapeutic agent, and (c) optionally at least one pharmaceutically acceptable carrier for simultaneous, separate or sequential use for the treatment of IBS, wherein the amounts of the compound of General Formula I or pharmaceutically acceptable salt or solvate thereof and the additional therapeutic agent are together effective in treating the IBS. In one embodiment, the compound of General Formula I or pharmaceutically acceptable salt or solvate thereof, and the additional therapeutic agent are administered simultaneously as separate dosages. In one embodiment, the compound of General Formula I or pharmaceutically acceptable salt or solvate thereof, and the additional therapeutic agent are administered as separate dosages sequentially in any order, in jointly therapeutically effective amounts, e.g. in daily or intermittently dosages. In one embodiment, compound of General Formula I or pharmaceutically acceptable salt or solvate thereof, and the additional therapeutic agent are administered simultaneously as a combined dosage.

Also provided herein is (i) a pharmaceutical combination for treating irritable bowel syndrome in a patient in need thereof, which comprises (a) a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, (b) at least one additional therapeutic agent (e.g., any of the exemplary additional therapeutic agents described herein for treating irritable bowel syndrome or known in the art), and (c) optionally at least one pharmaceutically acceptable carrier for simultaneous, separate or sequential use for the treatment of irritable bowel syndrome, wherein the amounts of the compound of General Formula I or pharmaceutically acceptable salt or solvate thereof and of the additional therapeutic agent are together effective in treating the irritable bowel syndrome; (ii) a pharmaceutical composition comprising such a combination; (iii) the use of such a combination for the preparation of a medicament for the treatment of irritable bowel syndrome; and (iv) a commercial package or product comprising such a combination as a combined preparation for simultaneous, separate or sequential use; and to a method of treatment of irritable bowel syndrome in a patient in need thereof. In one embodiment the patient is a human.

The term “pharmaceutical combination”, as used herein, refers to a pharmaceutical therapy resulting from the mixing or combining of more than one active ingredient and includes both fixed and non-fixed combinations of the active ingredients. The term “fixed combination” means that a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof and at least one additional therapeutic agent (e.g., an agent effective in treating irritable bowel syndrome), are both administered to a patient simultaneously in the form of a single composition or dosage. The term “non-fixed combination” means that a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof and at least one additional therapeutic agent (e.g., an agent effective in treating irritable bowel syndrome) are formulated as separate compositions or dosages, such that they may be administered to a patient in need thereof simultaneously, concurrently or sequentially with variable intervening time limits, wherein such administration provides effective levels of the two or more compounds in the body of the patient. In one embodiment, the compound of Formula I and the additional therapeutic agent are formulated as separate unit dosage forms, wherein the separate dosages forms are suitable for either sequential or simultaneous administration. These also apply to cocktail therapies, e.g. the administration of three or more active ingredients.

In some embodiments, a compound provided herein can be used as an agent for supportive care for a patient undergoing cancer treatment. For example, a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, can be useful to reduce one or more symptoms associated with treatment with one or more cancer therapies such as diarrheal or constipations complications and/or abdominal pain. See, for example, U.S. Publication No. 2015/0099762 and Hoffman, J. M. et al. Gastroenterology (2012) 142:844-854. Accordingly, a compound, or a pharmaceutically acceptable salt thereof, or composition provided herein can be administered to a patient to address one or more complications associated with cancer treatment (e.g., gastrointestinal complications such as diarrhea, constipation, or abdominal pain).

In some embodiments, a therapeutically effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, can be administered to a patient undergoing cancer treatment (e.g., a patient experiencing an adverse event associated with cancer treatment such as an immune-related adverse event or a gastrointestinal complication including diarrhea, constipation, and abdominal pain). For example, a compound provided herein, or a pharmaceutically acceptable salt thereof, can be used in the treatment of colitis or IBS associated with administration of a checkpoint inhibitor; see, e.g., Postow, M. A. et al. Journal of Clinical Oncology (2015) 33: 1974-1982. In some such embodiments, a compound provided herein, or a pharmaceutically acceptable salt thereof, can be formulated to exhibit low bioavailability and/or be targeted for delivery in the gastrointestinal tract. See, for example, U.S. Pat. No. 6,531,152.

Also provided is a method for inhibiting RET kinase activity in a cell, comprising contacting the cell with a compound of General Formula I. In one embodiment, the contacting is in vitro. In one embodiment, the contacting is in vivo. In one embodiment, the contacting is in vivo, wherein the method comprises administering an effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof to a subject having a cell having RET kinase activity. In some embodiments, the cell is a cancer cell. In one embodiment, the cancer cell is any cancer as described herein. In some embodiments, the cancer cell is a RET-associated cancer cell. In some embodiments, the cell is a gastrointestinal cell.

Also provided is a method for inhibiting RET kinase activity in a mammalian cell, comprising contacting the cell with a compound of General Formula I. In one embodiment, the contacting is in vitro. In one embodiment, the contacting is in vivo. In one embodiment, the contacting is in vivo, wherein the method comprises administering an effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof to a mammal having a cell having RET kinase activity. In some embodiments, the mammalian cell is a mammalian cancer cell. In one embodiment, the mammalian cancer cell is any cancer as described herein. In some embodiments, the mammalian cancer cell is a RET-associated cancer cell. In some embodiments, the mammalian cell is a gastrointestinal cell.

As used herein, the term “contacting” refers to the bringing together of indicated moieties in an in vitro system or an in vivo system. For example, “contacting” a RET kinase with a compound provided herein includes the administration of a compound provided herein to an individual or patient, such as a human, having a RET kinase, as well as, for example, introducing a compound provided herein into a sample containing a cellular or purified preparation containing the RET kinase.

Also provided herein is a method of inhibiting cell proliferation, in vitro or in vivo, the method comprising contacting a cell with an effective amount of a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, or a pharmaceutical composition thereof as defined herein

The phrase “effective amount” means an amount of compound that, when administered to a patient in need of such treatment, is sufficient to (i) treat a RET kinase-associated disease or disorder, (ii) attenuate, ameliorate, or eliminate one or more symptoms of the particular disease, condition, or disorder, or (iii) delay the onset of one or more symptoms of the particular disease, condition, or disorder described herein. The amount of a compound of General Formula I that will correspond to such an amount will vary depending upon factors such as the particular compound, disease condition and its severity, the identity (e.g., weight) of the patient in need of treatment, but can nevertheless be routinely determined by one skilled in the art.

When employed as pharmaceuticals, the compounds of General Formula I can be administered in the form of pharmaceutical compositions. These compositions can be prepared in a manner well known in the pharmaceutical art, and can be administered by a variety of routes, depending upon whether local or systemic treatment is desired and upon the area to be treated. Administration may be topical (including transdermal, epidermal, ophthalmic and to mucous membranes including intranasal, vaginal and rectal delivery), pulmonary (e.g., by inhalation or insufflation of powders or aerosols, including by nebulizer; intratracheal or intranasal), oral or parenteral. Oral administration can include a dosage form formulated for once-daily or twice-daily (BID) administration. Parenteral administration includes intravenous, intraarterial, subcutaneous, intraperitoneal intramuscular or injection or infusion; or intracranial, e.g., intrathecal or intraventricular, administration. Parenteral administration can be in the form of a single bolus dose, or may be, for example, by a continuous perfusion pump. Pharmaceutical compositions and formulations for topical administration may include transdermal patches, ointments, lotions, creams, gels, drops, suppositories, sprays, liquids and powders. Conventional pharmaceutical carriers, aqueous, powder or oily bases, thickeners and the like may be necessary or desirable

Also provided herein are pharmaceutical compositions which contain, as the active ingredient, a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof, in combination with one or more pharmaceutically acceptable carriers (excipients). In some embodiments, the composition is suitable for topical administration. In making the compositions provided herein, the active ingredient is typically mixed with an excipient, diluted by an excipient or enclosed within such a carrier in the form of, for example, a capsule, sachet, paper, or other container. When the excipient serves as a diluent, it can be a solid, semi-solid, or liquid material, which acts as a vehicle, carrier or medium for the active ingredient. Thus, the compositions can be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosols (as a solid or in a liquid medium), ointments containing, for example, up to 10% by weight of the active compound, soft and hard gelatin capsules, suppositories, sterile injectable solutions, and sterile packaged powders. In one embodiment, the composition is formulated for oral administration. In one embodiment, the composition is formulated as a tablet or capsule.

The compositions comprising a compound of General Formula I or a pharmaceutically acceptable salt or solvate thereof can be formulated in a unit dosage form, each dosage containing from about 5 to about 1,000 mg (1 g), more usually about 100 mg to about 500 mg, of the active ingredient. The term “unit dosage form” refers to physically discrete units suitable as unitary dosages for human subjects and other patients, each unit containing a predetermined quantity of active material (i.e., a compound for General Formula I as provided herein) calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient.

In some embodiments, the compositions provided herein contain from about 5 mg to about 50 mg of the active ingredient. One having ordinary skill in the art will appreciate that this embodies compounds or compositions containing about 5 mg to about 10 mg, about 10 mg to about 15 mg, about 15 mg to about 20 mg, about 20 mg to about 25 mg, about 25 mg to about 30 mg, about 30 mg to about 35 mg, about 35 mg to about 40 mg, about 40 mg to about 45 mg, or about 45 mg to about 50 mg of the active ingredient.

In some embodiments, the compositions provided herein contain from about 50 mg to about 500 mg of the active ingredient. One having ordinary skill in the art will appreciate that this embodies compounds or compositions containing about 50 mg to about 100 mg, about 100 mg to about 150 mg, about 150 mg to about 200 mg, about 200 mg to about 250 mg, about 250 mg to about 300 mg, about 350 mg to about 400 mg, or about 450 mg to about 500 mg of the active ingredient.

In some embodiments, the compositions provided herein contain from about 500 mg to about 1,000 mg of the active ingredient. One having ordinary skill in the art will appreciate that this embodies compounds or compositions containing about 500 mg to about 550 mg, about 550 mg to about 600 mg, about 600 mg to about 650 mg, about 650 mg to about 700 mg, about 700 mg to about 750 mg, about 750 mg to about 800 mg, about 800 mg to about 850 mg, about 850 mg to about 900 mg, about 900 mg to about 950 mg, or about 950 mg to about 1,000 mg of the active ingredient.

The active compound may be effective over a wide dosage range and is generally administered in a pharmaceutically effective amount. It will be understood, however, that the amount of the compound actually administered will usually be determined by a physician, according to the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound administered, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the like.

Provided herein are pharmaceutical kits useful, for example, in the treatment of RET-associated diseases or disorders, such as cancer or irritable bowel syndrome (IBS), which include one or more containers containing a pharmaceutical composition comprising a therapeutically effective amount of a compound provided herein. Such kits can further include, if desired, one or more of various conventional pharmaceutical kit components, such as, for example, containers with one or more pharmaceutically acceptable carriers, additional containers, etc., as will be readily apparent to those skilled in the art. Instructions, either as inserts or as labels, indicating quantities of the components to be administered, guidelines for administration, and/or guidelines for mixing the components, can also be included in the kit.

One skilled in the art will recognize that, both in vivo and in vitro trials using suitable, known and generally accepted cell and/or animal models are predictive of the ability of a test compound to treat or prevent a given disorder.

One skilled in the art will further recognize that human clinical trials including first-in-human, dose ranging and efficacy trials, in healthy patients and/or those suffering from a given disorder, may be completed according to methods well known in the clinical and medical arts.

The following examples illustrate the invention.

Biological Examples

RET Enzyme Assay

Compounds of General Formula I were screened for their ability to inhibit wild type and V804M mutant RET kinase using CisBio's HTRF® KinEASE™-TK assay technology. Briefly, N-terminal GST tagged recombinant human RET cytoplasmic domain (aa 658-end) from Eurofins (0.25 nM RET; Cat. No. 14-570M) or N-terminal GST tagged recombinant human V804M mutant RET cytoplasmic domain (aa 658-end) from Millipore (0.25 nM enzyme; Cat. No. 14-760) was incubated with 250 nM TK-substrate biotin (CisBio, part of Cat. No. 62TK0PEC) and 1 mM ATP along with test compound in a buffer consisting of 25 mM HEPES pH 7.4, 10 mM MgCl 2 , 0.01% Triton X-100, and 2% DMSO in a volume of 8 μL. Compounds were typically prepared in a threefold serial dilution in DMSO and added to the assay to give the appropriate final concentration. After a 30-minute incubation at 22° C., the reaction was quenched by adding 8 μL of quench solution containing 31.25 nM Sa-XL665 and 1× TK-ab-Cryptate in HTRF detection buffer (all from CisBio, part of Cat. No. 62TK0PEC). After a 1 hour incubation at 22° C., the extent of reaction was determined using a PerkinElmer EnVision multimode plate reader via HTRF dual wavelength detection, and the percent of control (POC) was calculated using a ratiometric emission factor. 100 POC was determined using no test compounds and 0 POC was determined using pre-quenched control reactions. The POC values were fit to a 4 parameter logistic curve, and the IC 50 is defined as the concentration of inhibitor at which the POC equals 50 for the fitted curve. The IC 50 values for the compounds tested in this assay are provided in Table 5.

RET Cell Assay

The cellular potency of a compound inhibiting RET kinase was determined in HEK-293 cells expressing a Kif5b-RET fusion protein. Briefly, HEK-293 cells expressing a Kif5b-RET fusion protein were plated at 50K cells/well in 96 well poly-D-Lysine coated plates the day prior to the assay. The cells were incubated for 1 hour with test compound in DMEM (Dulbecco's Modified Eagle Medium) at a final DMSO concentration of 0.5%. Compounds were typically prepared in a three fold serial dilution in DMSO and added to the assay to give the appropriate final concentration. After 1 hour the media was removed, the cells were fixed with 3.8% formaldehyde for 20 min, washed with PBS, and permeabilized for 10 min with 100% methanol. The plates were then washed with PBS-0.05% Tween20, and blocked with LI-COR Blocking solution (LI-COR catalog #927-40000) for 1 hour. Plates were washed with PBS-0.05% Tween20, then incubated with anti-phospho-RET(Tyr1062) (Santa Cruz catalog #sc-20252-R) antibody and anti-GAPDH (Millipore catalog # MAB374) antibody for 2 hours. The plates were washed with PBS-0.05% Tween20, and incubated with anti-rabbit 680 (Molecular Probes cat# A21109) and anti-mouse 800 (LI-COR catalog #926-32210) secondary antibodies for 1 hour. All antibodies were diluted in LI-COR Block containing 0.05% Tween. The plates were washed with PBS-0.05% Tween20, 100 μL PBS was added to each well, and the plates were read on a LI-COR Aerius fluorescent plate reader. The phospho-RET signal was normalized to the GAPDH signal. 100 POC (percent of control) was determined using no test compounds and 0 POC was determined using 1 μM of a control inhibitor. The POC values were fit to a 4 parameter logistic curve. The IC 50 value is the point where the curve crosses 50 POC. The IC 50 values for the compounds tested in this assay are provided in Table 5.

KDR Cell Assay

The cellular potency of a compound inhibiting KDR kinase was determined in HEK-293 cells expressing an inducible human KDR protein. Briefly, HEK-293 cells expressing KDR protein were plated at 40K cells/well in 96-well collagen (compounds of Example Nos. 2, 88, 290, 291, 295, 297, 298, 299, 332, 333, and 339) or poly-D-lysine (all other tested compounds) coated plates the day prior to the assay. Cells were incubated for 4 to 6 hours to allow them to adhere to the plate and then protein expression is induced by the addition of 1 μg/mL Doxycycline overnight. The cells were incubated for 1 hour with test compound in DMEM at a final DMSO concentration of 0.25%. Compounds were typically prepared in a three-fold serial dilution in DMSO and added to the assay to give the appropriate final concentration. After 1 hour, wells were stimulated with VEGF (75 ng/ml final; compounds of Example Nos. #2, 88, 290, 291, 295, 297, 298, 299, 332, 333, 339) or VEGF (56 ng/ml final; all other tested compounds) for 5 minutes at 37 C. The media was aspirated and 35 μL of a 1× lysis buffer was added. Plates were shaken for 1-2 mins to finalize cell lysis. The lysate was stored at −80° C. until ready for assay. Phospho-KDR was measured using a phospho-KDR kit (Catalog #K151BOC) purchased from Meso Scale Diagnostics (Rockville, Md.) according to the manufacturer's instructions. All values are expressed as percent of percent of control (POC). The POC values were fitted to a 4 parameter logistic curve fit and the IC 50 value is point where the curve crosses 50 POC. The IC 50 values for the compounds tested in this assay are provided in Table 5.

Synthetic Examples

Synthesis of Synthetic Intermediates

Examples P1 and P2

6-bromo-4-methoxypyrazolo[1,5-a]pyridine (P1) and 4-bromo-6-methoxypyrazolo[1,5-a]pyridine (P2)

To a solution of O-(mesitylsulfonyl)hydroxylamine (Intermediate R1, 26.6 g, 117 mmol) in DCM (570 mL) cooled to 0° C. was added 3-bromo-5-methoxypyridine (22.1 g, 117 mmol) in portions. The reaction mixture was stirred for 1 h at 0° C. then treated with additional 3-bromo-5-methoxypyridine (250 mg, 1.39 mmol) and stirred for an additional 2 h at 0° C. The reaction mixture was diluted with Et 2 O (600 mL), stirred at 0° C. for 10 min and then vacuum filtered, rinsed with Et 2 O (3×250 mL). Upon reduction in volume by about ⅓, the filtrate yielded additional precipitate which was collected by filtration. Both filter cakes were dried in vacuo to provide the title compound (39.3 g, 83% yield). 1 H NMR (CDCl 3 ) δ 9.25 (br s, 1H), 8.99 (m, 1H), 8.74 (m, 1H), 7.46 (m, 1H), 6.83 (s, 2H), 3.92 (s, 3H), 2.65 (s, 6H), 2.22 (s, 3H).

Step 2: Preparation of Ethyl 6-bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carboxylate and Ethyl 4-bromo-6-methoxypyrazolo[1,5-a]pyridine-3-carboxylate

To a magnetically stirred white suspension of 1-amino-3-bromo-5-methoxypyridin-1-ium 2,4,6-trimethylbenzenesulfonate (33.24 g, 82.42 mmol) in DMF (82 mL) at ambient temperature was added TEA (22.98 mL, 164.8 mmol), followed by drop-wise addition of ethyl propiolate (16.71 mL, 164.8 mmol). After vigorous stirring for 2 d, the reaction was slowly quenched via portion-wise addition to rapidly stirring ice water (820 mL). The mixture was stirred at ambient temperature for 10 min and then vacuum filtered. Solids collected were rinsed with water and air-dried, yielding the title compounds as an orange solid in an isomeric ratio of about 4:1 (by 1 H NMR) with the 6-Br isomer as the major isomer (21 g). The wet solid isomeric mixture (about 75% w/w) was directly used in Step 3 without further purification. MS (apci) m/z=298.9, 300.9 (M+H). Regioisomeric ratio was determined by MeO chemical shift in 1 H NMR (CDCl 3 ) δ 3.98 (6-Br isomer) vs. 3.83 (4-Br isomer).

Step 3: Preparation of 6-bromo-4-methoxypyrazolo[1,5-a]pyridine (P1) and 4-bromo-6-methoxypyrazolo[1,5-a]pyridine (P2)

The isomeric mixture of ethyl 6-bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carboxylate and ethyl 4-bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carboxylate from Step 2 (15 g, 50.1 mmol) was added to 48% HBr (114 mL) while stirring, then heated at 80° C. for 90 min followed by stirring at ambient temperature overnight. The resulting suspension was vacuum filtered and rinsed with water. The aqueous filtrate and the filter cake were treated independently. The filter cake was taken up in MTBE and vacuum filtered to remove insoluble impurities. The MTBE filtrate was dried over anhydrous Na 2 SO 4 , filtered and concentrated in vacuo to yield 6-bromo-4-methoxypyrazolo[1,5-a]pyridine (Intermediate P1) as a beige solid (about 98:2 6-/4-Br; 5.08 g). MS (apci) m/z=226.9, 228.9 (M+H). 1 H NMR (CDCl 3 ) δ 8.26 (m, 1H), 7.82 (d, 1H), 6.61 (m, 1H), 6.43 (m, 1H), 3.94 (s, 3H).

Independently the original aqueous reaction mixture filtrate was extracted with EtOAc (2×500 mL). The combined organic extracts were dried (Na 2 SO 4 ), filtered and concentrated in vacuo. The crude residue was taken up in DCM (50 mL) and then filtered to remove insoluble solids. Concentration of the DCM filtrate under vacuum followed by silica chromatography (0 to 50% EtOAc/hexanes) yielded a second batch of 6-bromo-4-methoxypyrazolo[1,5-a]pyridine (Intermediate P1) as white solid (upper R f spot, 2.06 g), as well as the minor isomer title compound 4-bromo-6-methoxypyrazolo[1,5-a]pyridine (Intermediate P2) also as white solid (lower R f spot, 1.32 g). MS (apci) m/z=226.9, 228.9 (M+H). 1 H NMR (CDCl 3 ) δ 8.02 (m, 1H), 7.85 (d, 1H), 7.17 (d, 1H), 6.55 (m, 1H), 3.80 (s, 3H).

Intermediate P3

6-bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carbaldehyde

To a 0° C. solution of 6-bromo-4-methoxypyrazolo[1,5-a]pyridine (Intermediate P1, 0.75 g, 3.303 mmol) in DMF (33 mL) was slowly added POCl 3 (0.92 mL, 9.909 mmol). The reaction was warmed to ambient temperature and stirred for 4 h and then diluted with H 2 O (30 mL). The resulting suspension was basified to pH 9-10 with 1 M NaOH (aq) , then stirred for 1 h and vacuum filtered, then rinsed sequentially with H 2 O (25 mL) and MTBE (50 mL) to yield the title compound (0.76 g, 90% yield). MS (apci) m/z=256.9 (M+H).

Intermediate P4

6-bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carbonitrile

To a suspension of 6-Bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carbaldehyde (Intermediate P3, 0.76 g, 3.0 mmol) and hydroxylamine hydrochloride (0.31 g, 4.5 mmol) in EtOH (40 mL) was added water (20 mL), and the reaction was stirred at 50° C. for 4 h. After cooling to ambient temperature the reaction mixture was concentrated in vacuo. The residue was suspended in water, then treated with saturated NaHCO 3(aq) and vacuum filtered. The solids were rinsed sequentially with H 2 O (25 mL) and MTBE (50 mL) to yield the title compound (0.68 g, 84% yield). MS (apci) m/z=271.9 (M+H).

A solution of (E)-6-bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carbaldehyde oxime (17.15 g, 63.50 mmol) in acetic anhydride (707 mL, 7.49 mol) was heated at 120° C. overnight. Following subsequent distillation to remove the acetic anhydride, the remaining residue was dried in vacuo to yield the title compound (15.92 g, 99.4% yield). 1 H NMR (CDCl 3 ) δ 8.32 (m, 1H), 8.12 (s, 1H), 6.74 (m, 1H), 4.03 (s, 3H).

Intermediate P5

3-cyano-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl trifluoromethanesulfonate

To a solution of 6-bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P4, 50 g, 198.4 mmol) and 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (49.53 g, 238.0 mmol) in dioxane (660 mL) was added 2 M Na 2 CO 3(aq) (297.5 mL, 595.1 mmol). The reaction mixture was sparged with nitrogen for 20 min before Pd(PPh 3 ) 4 (4.584 g, 3.967 mmol) was introduced, followed by additional 5 min of sparging with nitrogen. The reaction was heated at 80° C. for 18 h, then cooled to ambient temperature and vigorously stirred for 2 h. The suspension was vacuum filtered, rinsed sequentially with H 2 O (2×300 mL) and MTBE (3×300 mL), then dried in vacuo overnight to yield the title compound, which was used in the next step without further purification (52.62 g). MS (apci), m/z=254.1 (M+H).

To a suspension of 4-methoxy-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine-3-carbonitrile (52.62 g, 207.8 mmol) in DCE (2 L) was added AlCl 3 (92.86 g, 696.42 mmol), and the reaction mixture was stirred at 80° C. for 3 h. Additional AlCl 3 (2.5 g, 18.75 mmol) was introduced and the reaction was refluxed overnight. After cooling to ambient temperature the reaction mixture was diluted with DCE (1 L) and then quenched with portions of H 2 O (5×500 mL). The mixture was stirred at ambient temperature for 3 h before the resulting suspension was vacuum filtered and the filter cake dried in a vacuum oven (40° C.) to afford the title compound, which was used in the next step without further purification (43.69 g). MS (apci) m/z=239.9 (M+H). 1 H NMR (d 6 -DMSO) δ 11.38 (s, 1H), 8.74 (d, 1H), 8.50 (s, 1H), 8.21 (s, 1H), 7.94 (s, 1H), 6.96 (d, 1H), 3.88 (s, 3H).

Step 3: Preparation of 3-cyano-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl trifluoromethanesulfonate

To a suspension of 4-hydroxy-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine-3-carbonitrile (43.69 g, 182.6 mmol) in DMA (365 mL) was added DIEA (63.6 mL, 365.3 mmol) followed by 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide (71.77 g, 200.9 mmol). The resulting solution was stirred at ambient temperature for 2 h and then slowly poured into H 2 O (4 L). The resulting suspension was stirred for 2 h then vacuum filtered. The filter cake was rinsed with H 2 O (3×500 mL) and air dried overnight. The filter cake was then dissolved in DCM (1.6 L) and the resulting biphasic mixture was phase-separated. The organic layer was dried over anhydrous MgSO 4 , filtered through Celite® and rinsed with DCM. The combined organic layers were concentrated to yield the title compound as a 90% pure tan solid (64.3 g, 95% yield). The purity of the title compound can be further improved to >95% via silica chromatography (0-90% acetone/hexanes). 19 F NMR (CDCl 3 ) δ −72.0. 1 H NMR (CDCl 3 ) δ 8.66 (d, 1H), 8.29 (s, 1H), 7.77 (d, 1H), 7.70 (s, 1H), 7.55 (d, 1H), 4.01 (s, 3H).

Intermediate P6

4-(6-Fluoropyridin-3-yl)-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine-3-carbonitrile

In a pressure tube a solution of 3-cyano-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl trifluoromethanesulfonate (Intermediate P5, 500 mg, 1.35 mmol) in dioxane (13 mL) was treated sequentially with 2-fluoro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (451 mg, 2.02 mmol), Pd(PPh 3 ) 4 (77.8 mg, 0.0673 mmol), then 2 M Na 2 CO 3(aq) (3367 μL, 6.73 mmol). The resulting reaction mixture was sparged with nitrogen, sealed, and heated at 90° C. overnight. After cooling to ambient temperature the reaction mixture was diluted with water (10 mL) and vigorously stirred. The suspension was vacuum filtered and the filter cake was rinsed with water (3×5 mL), and subsequently dried in vacuo overnight to yield the title compound (285 mg, 67% yield). MS (apci), m/z=319.0 (M+H).

Intermediate P7

6-(1-Methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl trifluoromethanesulfonate

To a solution of 6-bromo-4-methoxypyrazolo[1,5-a]pyridine (Intermediate P1; 2.00 g, 227.1 mmol) and 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (2.02 g, 208.1 mmol) in dioxane (10 mL) was added 2 M Na 2 CO 3(aq) (8.1 mL, 17.6 mmol) and Pd(PPh 3 ) 4 (4.584 g, 3.967 mmol). The reaction mixture was purged with nitrogen for 2 min, sealed and heated at 90° C. for 4 h. After cooling to ambient temperature, the reaction mixture was diluted with water (50 mL) and stirred for 30 min. The resulting suspension was vacuum filtered, rinsed sequentially with water (2×20 mL) and Et 2 O (2×10 mL) to yield the crude title compound, which was used in the next step without further purification. MS (apci), m/z=229.1 (M+H).

4-Methoxy-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine (2.1 g, 9.2 mmol) was suspended in DCE (50 mL) and treated with AlCl 3 (6.134 g, 46.00 mmol). The resulting reaction mixture was heated at 90° C. overnight. Upon cooling to ambient temperature, the reaction mixture was quenched with Na 2 SO 4 *10H 2 O in THF (50 mL) and stirred for 2 h before filtering and concentrating in vacuo. The crude residue was taken up in saturated NH 4 Cl (aq) (50 mL) and extracted with EtOAc (2×100 mL). The combined organic extracts were filtered through PS paper and concentrated in vacuo to afford the crude title compound, which was used in the next step without further purification. MS (apci) m/z=215.1 (M+H).

Step 3: Preparation of 6-(1-Methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl Trifluoromethanesulfonate

A suspension of 6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-ol (1.0 g, 4.67 mmol), DIEA (4.1 mL, 23.3 mmol) and 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide (2.2 g, 6.07 mmol) in THF (20 mL) was stirred at ambient temperature overnight, then concentrated in vacuo and purified by silica chromatography (0-20% MeOH/EtOAc) to afford the title compound (757 mg, 47% yield). MS (apci) m/z=346.9 (M+H).

Intermediate P8

3-Chloro-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl Trifluoromethanesulfonate

To a solution of 6-bromo-4-methoxypyrazolo[1,5-a]pyridine (Intermediate P1 as a partial HBr salt; 1000 mg, 4.40 mmol) in DCM (16 mL) was added NCS (433.59 mg, 3.247 mmol) at ambient temperature. After stirring overnight, additional NCS (125 mg, 0.936 mmol) was introduced and the reaction was stirred for another 2 h. The mixture was then diluted with water (25 mL) and extracted with DCM (2×25 mL). The combined organic extracts were washed with water, dried over anhydrous MgSO 4 , filtered and concentrated to yield an 85:15 mixture of two components (1106 mg), with the major component being the title compound. 1 H NMR (CDCl 3 ): Major component δ 8.18 (d, 1H), 7.75 (s, 1H), 6.45 (d, 1H), 3.96 (s, 3H). Minor component δ 8.22 (d, 1H), 7.78 (s, 1H), 6.48 (d, 1H), 2.78 (s, 3H). Major component: MS (apci) m/z=260.1, 262.9 (M+H). This crude mixture was used in the next without further purification.

In a pressure tube a suspension of 6-bromo-3-chloro-4-methoxypyrazolo[1,5-a]pyridine (550 mg, 2.10 mmol) in dioxane (7 mL) was treated with 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (656 mg, 3.15 mmol), 2 M Na 2 CO 3(aq) (3155 μL, 6.31 mmol) and Pd(PPh 3 ) 4 (122 mg, 0.105 mmol). The resulting mixture was sparged with nitrogen and then heated at 90° C. overnight. After cooling to ambient temperature the reaction mixture was diluted with water (50 mL) and extracted with DCM (2×50 mL). The combined organic extracts were dried over anhydrous MgSO 4 and filtered, and the filtrate was concentrated. The crude residue was purified by silica chromatography (25-100% EtOAc/hexanes) to provide the title compound (393 mg, 71% yield). MS (apci) m/z=263.0 (M+H). 1 H NMR (CDCl 3 ) δ 8.16 (d, 1H), 7.76 (s, 1H), 7.75 (s, 1H), 7.62 (s, 1H), 6.46 (s, 1H), 4.01 (s, 3H), 3.99 (s, 1H).

A suspension of 3-chloro-4-methoxy-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine (1.0 g, 3.807 mmol) in 1 M BBr 3 in DCM (19.03 mL, 19.03 mmol) was stirred overnight at ambient temperature followed by another 22 h at 40° C. Upon cooling to ambient temperature, the reaction mixture was quenched with water (100 mL) and MeOH (10 mL). The resulting mixture was extracted with DCM (100 mL) and 10% MeOH in DCM (2×100 mL). The combined organic extracts were concentrated in vacuo to provide the crude title compound, which was used directly in the next step without further purification (1959 mg). MS (apci) m/z=249.0 (M+H).

Step 4: Preparation of 3-chloro-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl Trifluoromethanesulfonate

To a suspension of 3-chloro-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-ol (0.95 g, 3.82 mmol) in DCM (20 mL) was added DIEA (1.33 mL, 7.64 mmol) followed by 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide (1.50 g, 4.20 mmol). The resulting suspension was stirred at ambient temperature overnight and subsequently diluted with DCM (20 mL) and quenched with water (50 mL). The aqueous phase was extracted with DCM (3×50 mL) and the combined organic extracts were dried (MgSO 4 ), filtered, and concentrated. The crude residue was purified by silica chromatography (25-100% EtOAc/hexanes) to yield the title compound (860 mg, 59% yield). 1 H NMR (CDCl 3 ) δ 8.49 (d, 1H), 7.92 (s, 1H), 7.73 (s, 1H), 7.63 (s, 1H), 7.23 (d, 1H), 3.99 (s, 3H). 19 F NMR (CDCl 3 ) δ −72.5. 19 F NMR (CDCl 3 ) δ −72.5.

Intermediate P9

3-chloro-4-(6-fluoropyridin-3-yl)-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine

In a pressure tube a solution of 3-chloro-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl trifluoromethanesulfonate (Intermediate P8; 150 mg, 0.394 mmol) in dioxane (3 mL) was treated sequentially with 2-fluoro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (132 mg, 0.591 mmol), 2 M Na 2 CO 3(aq) (985 μL, 1.97 mmol) and Pd(PPh 3 ) 4 (22.8 mg, 0.0197 mmol). The reaction mixture was sparged with nitrogen and then heated at 90° C. overnight. After cooling to ambient temperature the reaction mixture was diluted with water (10 mL) and vigorously stirred. The suspension was vacuum filtered and the filter cake was rinsed sequentially with water (10 mL) and MTBE (3×5 mL), and subsequently dried in vacuo to yield the title compound (79 mg, 61% yield). MS (apci), m/z=327.9 (M+H).

Intermediate P10

4-Bromo-6-methoxypyrazolo[1,5-a]pyridine-3-carbaldehyde

A solution of 4-bromo-6-methoxypyrazolo[1,5-a]pyridine (Intermediate P2; 5.0 g, 22 mmol) in DMF (220 mL) was cooled to 0° C. and then slowly treated with POCl 3 (6.2 mL, 66 mmol). The reaction was warmed to ambient temperature and stirred overnight. The reaction mixture was cooled to 0° C., quenched with water (220 mL), and basified with 6 M NaOH(aq) to pH 9-10. The reaction mixture was stirred for 1 h and then vacuum filtered. The solids were rinsed sequentially with water (3×50 mL) and MTBE (3×50 mL). The collected solid was suspended in DCM (500 mL) and stirred in a sonicating bath for 30 min and then vacuum filtered. The filtrate was retained, while the filter cake was taken up in water (300 mL) and extracted with DCM (2×300 mL). The organic extracts, along with the retained DCM filtrate, were combined and dried over anhydrous Na 2 SO 4 , then filtered and concentrated in vacuo to provide the title compound (4.84 g, 86% yield). MS (apci), m/z=256.9 (M+H).

Intermediate P11

4-Bromo-6-methoxypyrazolo[1,5-a]pyridine-3-carbonitrile

To a suspension of 4-bromo-6-methoxypyrazolo[1,5-a]pyridine-3-carbaldehyde (Intermediate P10; 4.84 g, 19.0 mmol) in EtOH (253 mL) at ambient temperature was added water (127 mL) and hydroxylamine hydrochloride (1.98 g, 28.5 mmol). After stirring at 50° C. overnight, the reaction mixture was cooled to ambient temperature and concentrated in vacuo. The residue was suspended in water (150 mL) and then quenched slowly with saturated NaHCO 3(aq) (30 mL). After stirring for 1 hour at ambient temperature the suspension was vacuum filtered and the filter cake rinsed sequentially with H 2 O (500 mL) and MTBE (100 mL) to yield the title compound as a 2:1 E/Z mixture (5.13 g, quantitative yield), which was used in the next step without further purification. MS (apci) m/z=271.9 (M+H).

The E/Z mixture from Step 1 (4.95 g, 18.33 mmol) in acetic anhydride (172.9 mL, 1833 mmol) was stirred at 140° C. for 25 h, then cooled to ambient temperature. The resulting suspension was further cooled in an ice bath for 15 min and then vacuum filtered and rinsed sequentially with water (200 mL) and MTBE (300 mL) to provide the title compound (3.74 g, 81% yield). 1 H NMR (d 6 -DMSO) δ 8.70 (s, 1H), 8.60 (s, 1H), 7.78 (s, 1H), 3.83 (s, 3H).

Intermediate P12

4-bromo-6-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile

To a suspension of 4-Bromo-6-methoxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P11; 1500 mg, 5.951 mmol) in DCE (10 mL) was added AlCl 3 (2380 mg, 17.85 mmol), and the reaction mixture was stirred at 80° C. for 4 h. Upon cooling to ambient temperature, the reaction mixture was quenched with Na 2 SO 4 *10H 2 O in THF (100 mL), then stirred overnight and then filtered and concentrated in vacuo to afford the title compound (963 mg, 68% yield). MS (apci) m/z=238.0 (M−H).

Intermediate P13

Tert-Butyl 4-(5-(3-cyano-6-hydroxypyrazolo[1,5-a]pyridin-4-yl)pyridin-2-yl)piperazine-1-carboxylate

In a pressure tube a solution of 4-bromo-6-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P12; 419 mg, 1.76 mmol) in dioxane (30 mL) was treated with tert-butyl 4-(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl)piperazine-1-carboxylate (824 mg, 2.12 mmol), 2 M Na 2 CO 3(aq) (1764 μL, 3.53 mmol) and Pd(PPh 3 ) 4 (20.4 mg, 0.0176 mmol). The resulting reaction mixture was sparged with nitrogen for 5 min and then stirred at 100° C. for 4 h. After cooling to ambient temperature, the reaction mixture was diluted with saturated NH 4 Cl (aq) (20 mL) and brine (2 mL), and then extracted with EtOAc (3×50 mL). The combined organic extracts were filtered through PS paper and then concentrated in vacuo to afford the crude title compound, which was used without further purification. MS (apci) m/z=421.1 (M+H).

Intermediate P14

Tert-Butyl 4-(5-(3-cyano-6-(((trifluoromethyl)sulfonyl)oxy)pyrazolo[1,5-a]pyridin-4-yl)pyridin-2-yl)piperazine-1-carboxylate

Tert-butyl 4-(5-(3-cyano-6-hydroxypyrazolo[1,5-a]pyridin-4-yl)pyridin-2-yl)piperazine-1-carboxylate (Intermediate P13; 750 mg, 1.78 mmol), DIEA (1553 μL, 8.92 mmol) and 1,1,1-trifluoro-N-phenyl-N-((trifluoromethyl)sulfonyl)methanesulfonamide (828 mg, 2.32 mmol) were combined in THF (20 mL) and stirred at ambient temperature overnight. The reaction was subsequently concentrated in vacuo and directly purified by silica chromatography (20-100% EtOAc/hexanes) to yield the title compound (723 mg, 73% yield). MS (apci) m/z=553.1 (M+H).

Intermediate P15

4-(4-(4-(3,3-Dimethylbutanoyl)piperazin-1-yl)phenyl)-6-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile

In a pressure tube a solution of 4-bromo-6-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile, (Intermediate P12; 500 mg, 2.10 mmol) in dioxane (10 mL) was treated with 3,3-dimethyl-1-(4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)piperazin-1-yl)butan-1-one (Intermediate R11; 974 mg, 2.52 mmol), 2 M Na 2 CO 3(aq) (2100 μL, 4.20 mmol) and Pd(PPh 3 ) 4 (24.3 mg, 0.0210 mmol). The resulting reaction mixture was sparged with nitrogen for 5 min then heated at 100° C. overnight. After cooling to ambient temperature, the reaction mixture was diluted with water and brine (2 mL each) and then extracted with EtOAc (2×50 mL). The combined organic extracts were filtered through PS paper then concentrated in vacuo to afford the crude title compound, which was used without further purifications (510 mg, 58% yield). MS (apci), m/z=419.1 (M+H).

Intermediate P16

3-cyano-4-(4-(4-(3,3-dimethylbutanoyl)piperazin-1-yl)phenyl)pyrazolo[1,5-a]pyridin-6-yl Trifluoromethanesulfonate

To a suspension of 4-(4-(4-(3,3-dimethylbutanoyl)piperazin-1-yl)phenyl)-6-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P15; 510 mg, 1.22 mmol) in THF (20 mL) was added DIEA (439 μL, 2.44 mmol) and 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide (480 mg, 1.34 mmol). This reaction mixture was stirred at ambient temperature overnight then directly purified by silica chromatography (0-100% EtOAc/hexanes) to yield the title compound (611 mg, 91% yield).

Intermediate R1

O-(mesitylsulfonyl)hydroxylamine

To a 0° C. solution of 2,4,6-trimethylbenzene-1-sulfonyl chloride (10.0 g, 45.72 mmol) and tert-butyl hydroxycarbamate (6.088 g, 45.72 mmol) in MTBE (100 mL) was added TEA (14.46 mL, 48.01 mmol) drop-wise while stirring. The resulting suspension was stirred at 0° C. for an additional 30 min and then warmed to ambient temperature. The reaction was then diluted with water (100 mL), adjusted to pH 4 with 1 N HCl (aq) . The organic layer was dried (Na 2 SO 4 ), filtered and concentrated to yield the title compound initially as a yellowish oil, which upon drying overnight under high vacuum became a white solid (12.89 g, 89% yield). 1 H NMR (CDCl 3 ) δ 7.66 (br s, 1H), 6.98 (s, 2H), 2.67 (s, 6H), 2.32 (s, 3H), 1.31 (s, 9H).

To TFA (117 mL, 1521 mmol) at 0° C. was slowly added tert-butyl (mesitylsulfonyl)oxycarbamate (39.0 g, 124 mmol) over 25 min. The reaction mixture was stirred at 0° C. for 1.5 h and then quenched with the sequential addition of crushed ice (5×ca. 200 mL) and water (2×125 mL). The resulting thick suspension was vigorously stirred at ambient temperature for 5 min. Without allowing the filter cake to run dry, the solids were collected by careful vacuum filtration followed by subsequent rinsing with water (4 L) until the filtrate reached pH 6 (Caution: explosion risk exists with dry compound at ambient temperature). The wet filter cake was taken up in DCM (150 mL) and the resulting biphasic solution was separated. The DCM layer was dried over MgSO 4 for 30 min and then filtered and rinsed with DCM (420 mL) to provide the title compound as a 0.22 M solution in DCM.

Intermediate R2

Tert-Butyl 7-(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl)-4,7-diazaspiro[2.5]octane-4-carboxylate

A solution of tert-butyl 4,7-diazaspiro[2.5]octane-4-carboxylate (177 mg, 0.835 mmol) and 2-chloro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (100 mg, 0.418 mmol) in DMSO (1.4 mL) was heated to 150° C. in a pressure tube overnight. After cooling to ambient temperature the reaction mixture was diluted with EtOAc (30 mL) and washed with brine (3×25 mL). The combined organic extracts were dried over MgSO 4 , filtered and concentrated. The crude residue was purified by silica chromatography (0-100% EtOAc/hexanes) to provide the title compound (91 mg, 53% yield). 1 H NMR (CDCl 3 ) δ 8.51 (d, 1H), 7.80 (dd, 1H), 6.53 (d, 1H), 3.65 (m, 2H), 3.59 (m, 2H), 3.45 (s, 2H), 1.47 (s, 9H), 1.32 (s, 12H), 1.00 (m, 2H), 0.88 (m, 2H).

The borolane intermediates shown in Table A were prepared according the method used for the synthesis of Intermediate R2, using the appropriate starting materials.

Intermediate R9

Tert-Butyl ((1R,3r,5S)-8-(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl)-8-azabicyclo[3.2.1]octan-3-yl)carbamate

A solution of tert-butyl (1R,3r,5S)-8-azabicyclo[3.2.1]octan-3-ylcarbamate (378 mg, 1.67 mmol) and 2-chloro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (200 mg, 0.835 mmol) in DMSO (3 mL) was stirred at 150° C. in a pressure tube for 3 d. After cooling to ambient temperature the reaction mixture was diluted with water (10 mL) and the resulting suspension was filtered, rinsed with water and dried in vacuo to provide the title compound (228 mg, 64% yield). 1 H NMR (CDCl 3 ) δ 8.53 (dd, 1H), 7.79 (dd, 1H), 6.48 (d, 1H), 4.96 (br s, 1H), 4.55 (br s, 2H), 3.75 (br s, 1H), 2.14-2.27 (m, 4H), 2.01 (m, 2H), 1.67 (d, 2H), 1.44 (s, 9H), 1.32 (s, 12H).

Intermediate R10

Tert-Butyl 4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)piperidine-1-carboxylate

At ambient temperature, a suspension of 4-(4-bromophenyl)piperidine (1000 mg, 4.164 mmol) in DCM (20 mL) was treated with DIEA (1451 μL, 8.328 mmol) followed by Boc-anhydride (1064 μL, 4.581 mmol), and then stirred overnight. The reaction mixture was subsequently diluted with water (50 mL) and then extracted with DCM (3×50 mL). The combined organic extracts were dried (MgSO 4 ), filtered and concentrated in vacuo to afford the title compound (1363 mg, 96% yield). 1 H NMR (CDCl 3 ) δ 7.42 (m, 2H), 7.07 (m, 2H), 4.24 (m, 2H), 2.79 (dt, 2H), 2.61 (tt, 1H), 1.79 (m, 2H), 1.58 (qd, 2H), 1.48 (s, 9H).

Step 2: Preparation of Tert-Butyl 4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)piperidine-1-carboxylate

In a pressure tube a solution of tert-butyl 4-(4-bromophenyl)piperidine-1-carboxylate (1363 mg, 4.006 mmol) in dioxane was treated with bis(pinacolato)diboron (1526 mg, 6.009 mmol), KOAc (1179 mg, 12.02 mmol), and PdCl 2 (dppf).DCM (327.1 mg, 0.4006 mmol). The mixture was sparged with nitrogen for 1 min and then sealed and heated at 100° C. overnight. After cooling to ambient temperature, the reaction mixture was diluted with a mixture of EtOAc (75 mL)/water (50 mL)/brine (25 mL), and the resulting emulsion was filtered through Celite® and rinsed with EtOAc. The biphasic filtrate was separated and the organic phase was washed with brine and then dried (MgSO 4 ), filtered and concentrated in vacuo. The crude residue was purified by silica chromatography (0-50% EtOAc/hexanes) to afford the title compound (1437 mg, 93% yield). 1 H NMR (CDCl 3 ) δ 7.76 (d, 2H), 7.22 (m, 2H), 4.24 (d, 2H), 2.79 (dt, 2H), 2.65 (tt, 1H), 1.81 (m, 2H), 1.63 (dq, 2H), 1.48 (s, 9H), 1.33 (s, 12H).

Intermediate R11

3,3-dimethyl-1-(4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)piperazin-1-yl)butan-1-one

To a mixture of 1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)piperazine (850 mg, 2.95 mmol) and TEA (1233 μL, 8.85 mmol) in DCM (10 mL) was added 3,3-dimethylbutanoyl chloride (486 μL, 3.54 mmol). The reaction was stirred overnight at ambient temperature and subsequently quenched with MeOH (1 mL), concentrated in vacuo, taken up in water (5 mL) and sonicated. The solid was collected by filtration, washed with water (2 mL) and hexanes (3×5 mL) to afford the title compound (938 mg, 82% yield).

Intermediate P17

6-bromo-4-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile

A room temperature solution of 6-bromo-4-methoxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P4; 0.200 g, 0.793 mmol) in DCE (7.93 mL) was treated with AlCl 3 (0.529 g, 3.97 mmol), then stirred at 80° C. for 2 h. After cooling to room temperature, the reaction mixture was quenched with water (100 mL), and extracted with DCM. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered and concentrated in vacuo. The residue was purified by silica chromatography (0-75% EtOAc/Hexanes as the gradient eluent) to cleanly afford the title compound (78.6 mg, 42% yield). MS (apci) m/z=237.9 (M+H).

Intermediate P18

4-hydroxy-6-(1-(4-methoxybenzyl)-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine-3-carbonitrile

A room temperature solution of 6-bromo-4-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P17; 1.00 g, 4.20 mmol) in dioxane (42.0 mL) was treated with 1-(4-methoxybenzyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1.98 g, 6.30 mmol) and 2 M aqueous K 2 CO 3 (4.20 mL, 8.402 mmol), then sparged with N 2 for 5 min. The reaction mixture was treated with XPhos (0.401 g, 0.842 mmol) and Pd 2 (dba) 3 (0.192 g, 0.210 mmol), then sparged with N 2 for 5 min, sealed and stirred overnight at 80° C. After cooling to room temperature, the reaction mixture was diluted with water, and extracted with EtOAc. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered and concentrated in vacuo. The residue was purified by silica gel (Biotage Isolera, 80 g, Isco RediSep, 0-10% MeOH in DCM as the gradient eluent) to afford the title compound (1.06 g, 73% yield).

Intermediate P19

3-cyano-6-(1-(4-methoxybenzyl)-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl Trifluoromethanesulfonate

A room temperature solution of 4-hydroxy-6-(1-(4-methoxybenzyl)-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P18; 1.057 g, 3.061 mmol) in DCM (15.3 mL) was treated with 1,1,1-trifluoro-N-phenyl-N-((trifluoromethyl)sulfonyl)methanesulfonamide (2.187 g, 6.121 mmol) and DIEA (1.6 mL, 9.2 mmol). The reaction mixture was stirred overnight at room temperature, and then quenched with water. The resulting biphasic mixture was extracted with DCM. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (0-50% DCM/EtOAc as the gradient eluent) to afford the title compound (958 mg, 66% yield).

Intermediate P20

6-(1,5-dimethyl-1H-pyrazol-4-yl)-4-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile

A room temperature solution of 6-bromo-4-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P17; 0.250 g, 1.05 mmol) in dioxane (10.5 mL) was treated with 1,5-dimethyl-1H-pyrazole-4-boronic acid pinacol ester (0.350 g, 1.58 mmol) and 2M aqueous K 2 CO 3 (1.10 mL, 2.10 mmol), then sparged with N 2 for 5 min. The reaction mixture was treated with XPhos (0.100 g, 0.210 mmol) and Pd 2 (dba) 3 (0.0481 g, 0.0525 mmol), then sparged with N 2 for 5 min, sealed, and stirred overnight at 80° C. After cooling to room temperature, the reaction mixture was diluted with water, and extracted with EtOAc. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. 1:1 DCM and hexanes were added to the crude material and the solids were filtered to afford the title compound (0.135 g, 51% yield). MS (apci) m/z=254.1 (M+H).

Intermediate P21

3-cyano-6-(1,5-dimethyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl Trifluoromethanesulfonate

A room temperature solution of 6-(1,5-dimethyl-1H-pyrazol-4-yl)-4-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P20; 0.135 g, 0.533 mmol) in DCM (2.67 mL) was treated with 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide (0.209 g, 0.586 mmol) and DIEA (0.186 mL, 1.07 mmol). The reaction mixture was stirred overnight at room temperature, and then quenched with water. The resulting biphasic mixture was extracted with DCM. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (0-50% DCM/EtOAc as the gradient eluent) to afford the title compound (125 mg, 61% yield). MS (apci) m/z=386.0 (M+H).

Intermediate P22

6-(1,3-dimethyl-1H-pyrazol-4-yl)-4-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile

A room temperature solution of 6-bromo-4-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P17; 0.250 g, 1.05 mmol) in dioxane (10.5 mL) was treated with 1,3-dimethyl-1H-pyrazole-4-boronic acid pinacol ester (0.350 g, 1.58 mmol) and 2 M aqueous K 2 CO 3 (1.10 mL, 2.10 mmol), then sparged with N 2 for 5 min. The reaction mixture was treated with XPhos (0.100 g, 0.210 mmol) and Pd 2 (dba) 3 (0.0481 g, 0.0525 mmol), then sparged with N 2 for 5 min, sealed and stirred overnight at 80° C. After cooling to room temperature, the reaction mixture was diluted with water, and extracted with EtOAc. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. 1:1 DCM and hexanes were added to the crude material and the solids were filtered to afford the title compound (0.192 g, 72% yield). MS (apci) m/z=254.1 (M+H).

Intermediate P23

3-cyano-6-(1,3-dimethyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl Trifluoromethanesulfonate

A room temperature solution of 6-(1,3-dimethyl-1H-pyrazol-4-yl)-4-hydroxypyrazolo[1,5-a]pyridine-3-carbonitrile (Intermediate P22; 0.192 g, 0.757 mmol) in DCM (3.79 mL) was treated with 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide (0.298 g, 0.833 mmol) and DIEA (0.264 mL, 1.51 mmol). The reaction mixture was stirred overnight at room temperature, and then quenched with water. The resulting biphasic mixture was extracted with DCM. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (0-50% DCM/EtOAc as the gradient eluent) to afford the title compound (189 mg, 65% yield). MS (apci) m/z=386.0 (M+H).

Intermediate P24

3-iodo-4-methoxy-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine

A room temperature solution of 4-methoxy-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine (Intermediate P7, step 1; 1.90 g, 8.32 mmol) and PPTS (0.209 g, 0.832 mmol) in DCM (20 mL) was treated with NIS (1.97 g, 8.74 mmol) then stirred overnight at room temperature. The reaction mixture was diluted with DCM, and washed with 2 N aqueous NaOH. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (0-50% EtOAc in Hexanes as the gradient eluent) to afford the title compound (2.4 g, 81% yield). MS (apci) m/z=355.0 (M+H).

Intermediate P25

4-methoxy-3-methyl-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine

A mixture of 3-iodo-4-methoxy-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine (Intermediate P24; 2.4 g, 6.78 mmol), 2,4,6-trimethyl-1,3,5,2,4,6-trioxatriborinane (2.84 mL, 20.3 mmol), PdCl 2 (dppf).CH 2 C12 (0.553 g, 0.678 mmol), and K 2 CO 3 (4.68 g, 33.9 mmol) in DMF (67.8 mL) was sparged with Argon, then sealed and stirred for 18 h at 100° C. The reaction mixture was diluted with water (60 mL) and extracted with EtOAc (3×100 mL). The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (using 50-100% EtOAc in Hexanes as the gradient eluent) and then by reverse phase HPLC (5-95% water/ACN with 0.1% TFA as the gradient eluent) to afford the title compound (500 mg, 31% yield). MS (apci) m/z=243.1 (M+H).

Intermediate P26

3-methyl-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-ol

A room temperature solution of 4-methoxy-3-methyl-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine (Intermediate P25; 500 mg, 2.06 mmol) in DCE (20.6 mL) was treated with AlCl 3 (1.38 g, 10.3 mmol), then stirred for 2 h at 80° C. After cooling to room temperature, the reaction mixture was quenched with water (100 mL), and extracted with 20% iPrOH in DCM. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo to cleanly afford the title compound (390 mg, 83% yield). MS (apci) m/z=229.1 (M+H).

Intermediate P27

3-methyl-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridin-4-yl Trifluoromethanesulfonate

A room temperature solution of 3-methyl-6-(1-methyl-1H-pyrazol-4-yl)pyrazolo[1,5-a]pyridine-4-ol (Intermediate P26; 0.390 g, 1.71 mmol) in DCM (17.1 mL) was treated with DIEA (0.613 mL, 3.42 mmol) and 1,1,1-trifluoro-N-phenyl-N— ((trifluoromethyl)sulfonyl)methanesulfonamide (0.671 g, 1.88 mmol). The reaction mixture was stirred for 5 d at room temperature. The reaction mixture was purified directly by silica chromatography (25-75% EtOAc/Hexanes as the gradient eluent) to afford the title compound (400 mg, 65% yield). MS (apci) m/z=361.0 (M+H).

Intermediate R12

(R)-3-hydroxy-2-phenylpropanoic Acid

A solution of (S)-(−)-4-benzyl-2-oxazolidinone (1.34 g, 7.57 mmol) in THF (100 mL) was cooled to −78° C. then treated with 1.0 M lithium bis(trimethylsilyl)amide in THF (7.95 mL, 7.95 mmol). The reaction mixture was stirred for 30 min at −78° C., then stirred 16 h at room temperature, before quenching with water. The resulting biphasic mixture was extracted with EtOAc. The combined organic extracts were washed with water and brine, then dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (5-60% Hexanes-EtOAc as the gradient eluent) to cleanly afford the title compound (1.55 g, 69% yield). MS (apci) m/z=252 [(M-CO 2 )+1].

A room temperature solution of (S)-4-benzyl-3-(2-phenylacetyl)oxazolidin-2-one (step 1; 1.55 g, 5.25 mmol) in DCM (50 mL) was sparged with N 2 , then cooled to 0° C. The resulting degassed solution was treated with titanium (IV) chloride (0.604 mL, 5.51 mmol), and stirred for 5 min at 0° C., before treating with DIEA (1.01 mL, 5.77 mmol). The resulting mixture was stirred for 1 h at 0° C., then treated sequentially with 0.60 M 1,3,5-trioxane in DCM (10 mL, 6.04 mmol) and additional titanium (IV) chloride (0.604 mL, 5.51 mmol). The reaction mixture was stirred for an additional 4 h at 0° C., before quenching with saturated NH 4 Cl. The resulting biphasic mixture was extracted with DCM. The combined organic extracts were washed with water, then dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (5-50% DCM-Acetone as the gradient eluent) to cleanly afford the title compound (1.22 g, 71% yield). 1 H NMR (400 MHz, DMSO-d 6 ) δ 7.34-7.23 (m, 10H), 5.20-5.14 (m, 2H), 4.74-4.70 (m, 1H), 4.28-4.24 (t, 1H), 4.16-4.08 (m, 2H), 3.61-3.56 (m, 1H), 3.06-2.96 (m, 2H).

A cold (0° C.) solution of (S)-4-benzyl-3-((R)-3-hydroxy-2-phenylpropanoyl)oxazolidin-2-one (step 2; 1.22 g, 3.75 mmol) in THF (40 mL) was treated sequentially with 30% (w/w) aqueous H 2 O 2 (3.60 mL, 37.5 mmol) and 2 M aqueous LiOH in (3.75 mL, 7.50 mmol). The resulting reaction mixture was stirred for 2 h at room temperature. The reaction mixture was treated with 2 M aqueous KOH (3.75 mL, 7.50 mmol), and refluxed for 2 h. After cooling to room temperature, the reaction mixture was treated with 1 M aqueous Na 2 SO 3 (5 mL), before concentrating in vacuo to remove the volatile organics. The resulting aqueous residue was diluted with Et 2 O, and washed with 1 M aqueous NaOH. The aqueous extracts were acidified to pH 2 using 4 M aqueous HCl, and extracted with 4:1 DCM/iPrOH. The combined DCM/iPrOH extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by C18 reverse phase chromatography (5-95% water/ACN with 0.1% TFA as the gradient eluent) to cleanly afford the title compound (355.6 mg, 57% yield). 1 H NMR (400 MHz, DMSO-d 6 ) δ 12.34 (s, 1H), 7.34-7.23 (m, 5H), 3.93-3.89 (t, 1H), 3.65-3.54 (m, 2H).

Intermediate R13

Tert-Butyl 3-(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine-2-yl)azetidine-1-carboxylate

A room temperature suspension of zinc dust (<10 um, 98+%; 0.353 g, 5.40 mmol) in THF (10 mL) was treated with 1,2-dibromoethane (0.0310 mL, 0.360 mmol) and chlorotrimethylsilane (0.0457 mL, 0.360 mmol) then stirred for 15 min at 60° C. The resulting mixture was treated with a solution of tert-butyl 3-iodoazetidine-1-carboxylate (1.02 g, 3.60 mmol) in DMA (10 mL), and stirred an additional 15 min at 60° C. before cooling to room temperature. The reaction mixture was treated with 2,5-dibromopyridine (0.896 g, 3.78 mmol), PdCl 2 (dppf).CH 2 C12 (0.147 g, 0.180 mmol), and CuI (0.0343 g, 0.180 mmol), sparged with Argon, sealed, and stirred 16 h at 80° C. The reaction mixture was cooled to room temperature, diluted with EtOAc and water, and then filtered. The filtrate was diluted with additional EtOAc, and washed with water and brine. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (5-70% Hexanes-EtOAc as the gradient eluent) to cleanly afford the title compound (357.6 mg, 32% yield). 1 H NMR (400 MHz, DMSO-d 6 ) δ 8.72-8.71 (m, 1H), 8.01-7.98 (m, 1H), 7.34-7.31 (m, 1H), 4.19-4.15 (m, 2H), 3.96-3.87 (m, 3H), 1.39 (s, 9H).

Step 2: Preparation of Tert-Butyl 3-(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine-2-yl)azetidine-1-carboxylate

A room temperature solution of tert-butyl 3-(5-bromopyridin-2-yl)azetidine-1-carboxylate (step 1; 153.5 mg, 0.4901 mmol) in dioxane (4.9 mL) was treated with bis(pinacolato)diboron (136.9 mg, 0.5391 mmol), PdCl 2 (dppf).CH 2 C12 (40.02 mg, 0.04901 mmol), and CH 3 CO 2 K (144.3 mg, 1.470 mmol). The resulting mixture was sparged with Argon, sealed, and stirred 16 h at 100° C. before cooling to room temperature. The reaction mixture was diluted with EtOAc, and washed with water and brine. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo to afford the title compound (176.0 mg, 99.7% yield). MS (apci) m/z=279.1; (M(BOH)+1).

The compounds in Table DD were prepared according to the method described for Intermediate R13, replacing tert-butyl 3-iodoazetidine-1-carboxylate with the appropriate alkyl iodide in Step 1. Reactions were monitored by LCMS, and reaction times were adjusted accordingly. Products were purified as in Intermediate R13 utilizing the appropriate gradient eluent in chromatography to cleanly afford the title compounds.

Intermediate R16

1-(5-boronopyridin-2-yl)-4-ethylpiperidine-4-carboxylic Acid

A room temperature solution of 2-fluoro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (2.0 g, 9.0 mmol) in DMSO (18 mL) was treated with 4-ethylpiperidine-4-carboxylic acid (4.7 g, 30 mmol) and K 2 CO 3 (5.0 g, 36 mmol), then stirred overnight at 80° C. After cooling to room temperature, the reaction mixture was diluted with water, and the resulting mixture was extracted with 20% MeOH/DCM. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo to afford the title compound containing impurities (4.2 g, quantitative yield). The material was used without further purification. MS (apci) m/z=279.1 (M+H).

Intermediate R17

(6-(4-ethyl-4-(isopropylcarbamoyl)piperidin-1-yl)pyridin-3-yl)boronic Acid

A room temperature solution of 1-(5-boronopyridin-2-yl)-4-ethylpiperidine-4-carboxylic acid (Intermediate R16; 2.45 g, 8.81 mmol) in DMA (35.2 mL) was treated with DIEA (8.44 mL, 48.5 mmol), propan-2-amine (2.25 mL, 26.4 mmol), and HATU (8.37 g, 22.0 mmol), then allowed to stir overnight at room temperature. The reaction mixture was diluted with water and extracted with 20% MeOH/DCM. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The crude material was purified by C18 reverse phase chromatography (0-80% ACN/water as the gradient eluent) to afford the title compound (1.0 g, 36% yield). MS (apci) m/z=320.2 (M+H).

Intermediate R18

(S)-(6-(4-(3-methoxypyrrolidine-1-carbonyl)piperazin-1-yl)pyridin-3-yl)boronic Acid

A room temperature solution of (6-(piperazin-1-yl)pyridin-3-yl)boronic acid (1.5 g, 7.25 mmol) in DMA (36.2 mL) was treated with DIEA (5.05 mL, 29.0 mmol) and stirred for 20 min at room temperature and then treated with 4-nitrophenyl carbonochloridate (2.92 g, 14.5 mmol). The resulting mixture was stirred overnight at room temperature. DIEA (5 mL, 29.0 mmol) and (S)-3-methoxypyrrolidine (3.66 g, 36.2 mmol) were added, and the reaction mixture was stirred for 48 h at room temperature. The reaction mixture was diluted with water and extracted with 20% MeOH/DCM. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by C18 reverse phase chromatography (0-40% ACN/water as the gradient eluent) to afford the title compound (1.0 g, 41% yield). MS (apci) m/z=335.1 (M+H).

Intermediate R19

1-ethyl-3-vinyl-1H-pyrazole

A room temperature solution of 1-ethyl-3-iodopyrazole (2.52 g, 11.4 mmol) in 4:1 dioxane/water (100 mL) was treated with potassium vinyltrifluoroborate (1.67 g, 12.5 mmol), XPhos (0.107 g, 0.225 mmol) and Pd 2 (dba) 3 (0.0516 g, 0.0563 mmol), then sparged with Argon, sealed, and stirred 16 h at 100° C. After cooling to room temperature, the reaction mixture was diluted with water, extracted with DCM, and filtered. The filtrate was diluted with additional DCM, and washed with water. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (5-70% Hexanes-EtOAc as the gradient eluent) to afford the title compound (689.1 mg, 50% yield). MS (apci) m/z=123.1 (M+H).

Intermediate R20

1,3-diethyl-1H-pyrazole

A room temperature solution of 1-ethyl-3-vinyl-1H-pyrazole (Intermediate R19; 689.1 mg, 5.641 mmol) in MeOH (28 mL) was treated with 10% Pd/C (600.3 mg, 0.2820 mmol). The resulting mixture was sparged with N 2 and then with H 2 for several minutes, then stirred under an atmosphere of H 2 for 16 h at ambient temperature and pressure. The resulting mixture was filtered through GF/F paper and the filtrate was concentrated in vacuo to afford the title compound (453.3 mg, 65% yield). MS (apci) m/z=125.2 (M+H).

Intermediate R21

4-bromo-1,3-diethyl-1H-pyrazole

A room temperature solution of 1,3-diethyl-1H-pyrazole (Intermediate R20; 390.2 mg, 3.142 mmol) in ACN (30 mL) was treated with NBS (559.2 mg, 3.142 mmol), then stirred for 16 h at room temperature. The reaction mixture was concentrated in vacuo. The residue was purified by silica chromatography (5-50% Hexanes-EtOAc as the gradient eluent) to afford the title compound (418.2 mg, 66% yield). MS (apci) m/z=203.0 (M+H). 1 H NMR (400 MHz, DMSO-d 6 ) δ 7.86 (s, 1H), 4.07-4.01 (q, 2H), 2.52-2.47 (q, 2H), 1.34-1.30 (t, 3H), 1.16-1.12 (t, 3H).

Intermediate R22

1-ethyl-3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

A −78° C. solution of 4-bromo-1-ethyl-3-methyl-1H-pyrazole (404.4 mg, 2.139 mmol) in THF (21 mL) was treated dropwise with 2.5 M n-BuLi in hexanes (1198 μL, 2.995 mmol). The resulting mixture was stirred for 30 min at −78° C., then treated with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (916.4 μL, 4.492 mmol). The reaction mixture was stirred for 30 min at room temperature, and then treated with saturated NH 4 Cl. The biphasic mixture was extracted with EtOAc, and the combined organic extracts were washed with brine. The combined organic extracts were dried over anhydrous Na 2 SO 4 , filtered, and concentrated in vacuo. The residue was purified by silica chromatography (5-70% Hexanes-EtOAc as the gradient eluent) to afford the title compound (324.5 mg, 64% yield). 1 H NMR (400 MHz, DMSO-d 6 ) δ 7.77 (s, 1H), 4.05-3.99 (q, 2H), 2.21 (s, 3H), 1.33-1.29 (t, 3H), 1.23 (s, 12H).

The compounds in Table EE were prepared according to the method described for Intermediate R22, replacing 4-bromo-1-ethyl-3-methyl-1H-pyrazole with the appropriate commercially available bromopyrazole (except where noted). Reactions were monitored by LCMS, and reaction times were adjusted accordingly. Products were purified as in Intermediate R22 utilizing the appropriate gradient eluent in chromatography to cleanly afford the title compounds.

Intermediate R27

Tert-Butyl 4-(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-3-yl)piperazine-1-carboxylate

A room temperature solution of tert-butyl 4-(6-chloropyridin-3-yl)piperazine-1-carboxylate (100 mg, 0.336 mmol) in dioxane (4 mL) was treated with bis(pinacolato)diboron (93.8 mg, 0.369 mmol), Pd(OAc) 2 (9.05 mg, 0.0403 mmol), X-Phos (28.8 mg, 0.0604 mmol), and KOAc (98.9 mg, 1.01 mmol). The resulting mixture was sparged with Argon, sealed, and stirred overnight at 90° C. before cooling to room temperature. The reaction mixture was concentrated in vacuo and the crude product was used in the next step without purification, assuming quantitative yield. MS (apci) m/z=208 (M(B(OH) 2 -BOC).

Preparation of Synthetic Examples

Triphosgene (129 mg, 0.436 mmol) was added in small portions over a 30 min period to a suspension of (S)-3-methoxypyrrolidine hydrochloride (200 mg, 1.45 mmol) and DIEA (1.52 mL, 8.72 mmol) in DCM (3.48 mL). The resulting mixture was stirred at ambient temperature for 3 h to provide the title compound as a fine suspension in DCM (0.25 M) which was used in the next step without further purification.

Step 2: Preparation of (S)-6-(1-(difluoromethyl)-1H-pyrazol-4-yl)-4-(6-(4-(3-methoxypyrrolidine-1-carbonyl)piperazin-1-yl)pyridin-3-yl)pyrazolo[1,5-a]pyridine-3-carbonitrile

To a mixture of 6-(1-(difluoromethyl)-1H-pyrazol-4-yl)-4-(6-(piperazin-1-yl)pyridin-3-yl)pyrazolo[1,5-a]pyridine-3-carbonitrile dihydrochloride (20 mg, 0.0405 mmol) and DIEA (42.4 μL, 0.243 mmol) in DCM (405 μL) was added (S)-3-methoxypyrrolidine-1-carbonyl chloride in DCM (0.25 M, 195 μL, 0.0486 mmol). The reaction was stirred at ambient temperature for 3 d and then directly purified by reverse phase chromatography (0-75% ACN/water) to afford the title compound (1.8 mg, 8% yield). MS (apci) m/z=548.1 (M+H).