Oligonucleotides for reduction of PD-L1 expression

The present application is a continuation of U.S. patent application Ser. No. 16/839,025 filed Apr. 2, 2020, now U.S. Pat. No. 10,829,555, entitled “OLIGONUCLEOTIDES FOR REDUCTION OF PD-L1 EXPRESSION,” which is a continuation of U.S. Pat. No. 10,745,480 issued Aug. 18, 2020, entitled “OLIGONUCLEOTIDES FOR REDUCTION OF PD-L1 EXPRESSION,” which is a continuation of U.S. patent application Ser. No. 15/458,800, entitled “OLIGONUCLEOTIDES FOR REDUCTION OF PD-L1 EXPRESSION,” filed on 14 Mar. 2017, and claims priority to EP 16160149.7, entitled “OLIGONUCLEOTIDES FOR REDUCTION OF PD-L1 EXPRESSION,” filed on 14 Mar. 2016, the contents of each of which is incorporated herein by reference.

The present invention relates to oligonucleotides (oligomers) that are complementary to programmed death ligand-1 (PD-L1), leading to reduction of the expression of PD-L1 the liver.

The present invention also relates to a method of alleviating the T cell exhaustion caused by an infection of the liver or cancer in the liver. Relevant infections are chronic HBV, HCV and HDV and parasite infections like malaria and toxoplasmosis (e.g. caused by protozoa of the Plasmodium , in particular of the species P. vivax, P. malariae and P. falciparum ).

The costimulatory pathway consisting of the programmed death-1 (PD-1) receptor and its ligand, PD-L1 (or B7-H1 or CD274) is known to contribute directly to T cell exhaustion resulting in lack of viral control during chronic infections of the liver. The PD-1 pathway also plays a role in autoimmunity as mice disrupted in this pathway develop autoimmune diseases.

It has been shown that antibodies that block the interaction between PD-1 and PD-L1 enhance T cell responses, in particular the response of CD8+ cytotoxic T cells (see Barber et al 2006 Nature Vol 439 p 682 and Maier et al 2007 J. Immunol. Vol 178 p 2714).

WO 2006/042237 describes a method of diagnosing cancer by assessing PD-L1 (B7-H1) expression in tumors and suggests delivering an agent, which interferes with the PD-1/PD-L1 interaction, to a patient. Interfering agents can be antibodies, antibody fragments, siRNA or antisense oligonucleotides. There are no specific examples of such interfering agents nor is there any mentioning of chronic liver infections.

RNA interference mediated inhibition of PD-L1 using double stranded RNA (dsRNA, RNAi or siRNA) molecules have also been disclosed in for example WO 2005/007855, WO 2007/084865 and U.S. Pat. No. 8,507,663. None of these describes targeted delivery to the liver. Dolina et al. 2013 Molecular Therapy-Nucleic Acids, 2 e72 describes in vivo delivery of PD-L1 targeting siRNA molecules to Kupffer cells thereby enhancing NK and CD8+ T cell clearance in MCMV infected mice. This paper concludes that PD-L1 targeting siRNA molecules delivered to hepatocytes are not effective in relation to enhancing CD8+ T cell effector function.

The siRNA approach is significantly different from the single stranded antisense oligonucleotide approach since the biodistribution and the mode of actions is quite different. As described in Xu et al 2003 Biochem. Biophys. Res. Comm. Vol 306 page 712-717, antisense oligonucleotides and siRNAs have different preferences for target sites in the mRNA.

WO2016/138278 describes inhibition of immune checkpoints including PD-L1, using two or more single stranded antisense oligonucleotides that are linked at their 5′ ends. The application does not mention HBV or targeted delivery to the liver.

The present invention identifies novel oligonucleotides and oligonucleotide conjugates which reduce PD-L1 mRNA very efficiently in liver cells, both in parenchymal cells (e.g. hepatocytes) and in non-parenchymal cells such as Kupffer cells and liver sinusoidal endothelial cells (LSECs). By reducing or silencing PD-L1, the oligonucleotides and oligonucleotide conjugates decrease PD-1-mediated inhibition and thereby promote immunostimulation of exhausted T cells. Alleviation of the T cell exhaustion in a chronic pathogenic infection of the liver will result in regained immune control and reduced levels of viral antigens in the blood during a chronic pathogenic infection of the liver. Natural killer (NK) cells and natural killer T (NKT) cells may also be activated by the oligonucleotides and oligonucleotide conjugates of the present invention.

The oligonucleotide conjugates secures local reduction of PD-L1 in liver cells and therefore reduces the risk of autoimmune side effects, such as pneumonitis, non-viral hepatitis and colitis associated with systemic depletion of PD-L1.

The present invention relates to oligonucleotides or conjugates thereof targeting a nucleic acid capable of modulating the expression of PD-L1 and to treat or prevent diseases related to the functioning of the PD-L1. The oligonucleotides or oligonucleotide conjugates may in particular be used to treat diseases where the immune response against an infectious agent has been exhausted.

Accordingly, in a first aspect the invention provides oligonucleotides which comprise a contiguous nucleotide sequence of 10 to 30 nucleotides in length with at least 90% complementarity to a PD-L1 target nucleic acid. The oligonucleotide can be an antisense oligonucleotide, preferably with a gapmer design. Preferably, the oligonucleotide is capable of inhibiting the expression of PD-L1 by cleavage of a target nucleic acid. The cleavage is preferably achieved via nuclease recruitment.

In a further aspect, the oligonucleotide is conjugated to at least one asialoglycoprotein receptor targeting conjugate moiety, such as a conjugate moiety comprising at least one N-Acetylgalactosamine (GalNAc) moiety. The conjugation moiety and the oligonucleotide may be linked together by a linker, in particular a biocleavable linker.

In a further aspect, the invention provides pharmaceutical compositions comprising the oligonucleotides or oligonucleotide conjugates of the invention and pharmaceutically acceptable diluents, carriers, salts and/or adjuvants.

In a further aspect, the invention provides methods for in vivo or in vitro method for reduction of PD-L1 expression in a target cell which is expressing PD-L1, by administering an oligonucleotide or composition of the invention in an effective amount to said cell.

In a further aspect, the invention provides oligonucleotides, oligonucleotide conjugates or pharmaceutical compositions for use in restoration of immunity against a virus or parasite.

In a further aspect, the invention provides oligonucleotides, oligonucleotide conjugates or pharmaceutical compositions for use as a medicament.

In a further aspect the invention provides methods for treating or preventing a disease, disorder or dysfunction by administering a therapeutically or prophylactically effective amount of the oligonucleotide of the invention to a subject suffering from or susceptible to the disease, disorder or dysfunction, in particular diseases selected from viral liver infections or parasite infections.

In a further aspect the oligonucleotide, oligonucleotide conjugates or pharmaceutical composition of the invention is used in the treatment or prevention of viral liver infections such as HBV, HCV and HDV or a parasite infections such as malaria, toxoplasmosis, leishmaniasis and trypanosomiasis or liver cancer or metastases in the liver.

FIG. 1 : Illustrates exemplary antisense oligonucleotide conjugates, where the oligonucleotide either is represented as a wavy line (A-D) or as “oligonucleotide” (E-H) or as T 2 (I) and the asialoglycoprotein receptor targeting conjugate moieties are trivalent N-acetylgalactosamine moieties. Compounds A to D comprise a di-lysine brancher molecule a PEG3 spacer and three terminal GalNAc carbohydrate moieties. In compound A and B the oligonucleotide is attached directly to the asialoglycoprotein receptor targeting conjugate moiety without a linker. In compound C and D the oligonucleotide is attached directly to the asialoglycoprotein receptor targeting conjugate moiety via a C6 linker. Compounds E-I comprise a trebler brancher molecule and spacers of varying length and structure and three terminal GalNAc carbohydrate moieties.

FIG. 2 : Graph showing EC50 (A) and PD-L1 knock down as % of saline (B) for the compounds tested in Example 2, in relation to their position on the target nucleic acid. The cell line in which the compound were tested are THP1(●) and Karpas (*).

FIG. 3 : Structural formula of the trivalent GalNAc cluster (GN2). GN2 is useful as conjugation moiety in the present invention. The wavy line illustrates the site of conjugation of the cluster to e.g. a C6 amino linker or directly to the oligonucleotide.

FIG. 4 : Structural formula of CMP ID NO 766_2.

FIG. 5 : Structural formula of CMP ID NO 767_2.

FIG. 6 : Structural formula of CMP ID NO 768_2.

FIG. 7 : Structural formula of CMP ID NO 769_2.

FIG. 8 : Structural formula of CMP ID NO 770_2.

FIG. 9 : Western blot detecting PD-L1 protein expression in liver from poly(IC) induced animals following treatment with saline and the indicated CMP ID NO's. Each blot shows a naked oligonucleotide versus a GalNAc conjugated version of the same oligonucleotide, blot A) CMP ID NO 744_1 and 755_2, B) CMP ID NO 747_1 and 758_2, C) CMP ID NO 748_1 and 759_2, D) CMP ID NO 752_1 and 763_2 and E) CMP ID NO 753_1 and 764_2. The upper band is the vinculin loading control, the lower band is the PD-L1 protein. The first lane in each blot show saline treated mice without Poly(IC) induction. These mice express very little PD-L protein.

FIG. 10 : Population of mononuclear cells in the liver after treatment with ● vehicle (group 10 and 1), ♦ DNA vaccine (group 11 and 2), ◯ anti-PD-L1 antibody (group 12), ▴ naked PD-L1 ASO+DNA vaccine (group 7) or Δ GalNAc conjugated PD-L1 ASO+DNA vaccine (group 8), for each group the individual animals are represented and the average is indicated by the vertical line for each group (see table 18). Statistical significance between the DNA vaccine group and the three treatment groups has been assessed and if present it is indicated by * between the groups (*=P<0.05, ***=P<0.001 and ****=P<0.0001). A) represents the number of T cells in the liver following treatment. B) represents the fraction of CD4+ T cells and C) represents the fraction of CD8+ T cells.

FIG. 11 : Modulation of PD-L1 positive cells in the liver after treatment with ● vehicle (group 10 and 1), ♦ DNA vaccine (group 11 and 2), ◯ anti-PD-L1 antibody (group 12), ▴ naked PD-L1 ASO+DNA vaccine (group 7) or Δ GalNAc conjugated PD-L1 ASO+DNA vaccine (group 8), for each group the individual animals are represented and the average is indicated by the vertical line for each group (see table 19). Statistical significance between the DNA vaccine group and the three treatment groups has been assessed and if present it is indicated by * between the groups (*=P<0.05 and ****=P<0.0001). A) represents the percentage of CD8+ T cells which express PD-L1 in the liver following treatment. B) represents the percentage of CD4+ T cells which express PD-L1 in the liver following treatment and C) represents the percentage of B cells which express PD-L1 in the liver following treatment.

FIG. 12 : HBV antigen specific CD8+ cytokine secreting cells in the liver after treatment with ● vehicle (group 10 and 1), ♦ DNA vaccine (group 11 and 2), ◯ anti-PD-L1 antibody (group 12), ▴ naked PD-L1 ASO+DNA vaccine (group 7) or Δ GalNAc conjugated PD-L1 ASO+DNA vaccine (group 8), for each group the individual animals are represented and the average is indicated by the vertical line for each group (see table 20). Statistical significance between the DNA vaccine group and the three treatment groups has been assessed and if present it is indicated by * between the groups (*=P<0.05). A) represents the percentage of IFN-γ secreting CD8+ T cells in the liver which are specific towards HBV PreS2+S antigen following treatment. B) represents the percentage of IFN-γ secreting CD8+ T cells in the liver which are specific towards HBV core antigen following treatment and C) represents the percentage of IFN-γ and TNF-α secreting CD8+ T cells in the liver which are specific towards HBV PreS2+S antigen following treatment.

FIG. 13 : HBV-DNA, HBsAg and HBeAg in AAV/HBV mice following treatment with GalNAc conjugated PD-L1 antisense CMP NO: 7592 (▾) compared to vehicle (▪). The vertical line indicates the end of treatment.

Oligonucleotide

The term “oligonucleotide” as used herein is defined as it is generally understood by the skilled person as a molecule comprising two or more covalently linked nucleosides. Such covalently bound nucleosides may also be referred to as nucleic acid molecules or oligomers. Oligonucleotides are commonly made in the laboratory by solid-phase chemical synthesis followed by purification. When referring to a sequence of the oligonucleotide, reference is made to the sequence or order of nucleobase moieties, or modifications thereof, of the covalently linked nucleotides or nucleosides. The oligonucleotide of the invention is man-made, and is chemically synthesized, and is typically purified or isolated. The oligonucleotide of the invention may comprise one or more modified nucleosides or nucleotides.

Antisense Oligonucleotides

The term “Antisense oligonucleotide” as used herein is defined as oligonucleotides capable of modulating expression of a target gene by hybridizing to a target nucleic acid, in particular to a contiguous sequence on a target nucleic acid. The antisense oligonucleotides are not essentially double stranded and are therefore not siRNAs. Preferably, the antisense oligonucleotides of the present invention are single stranded.

Contiguous Nucleotide Sequence

The term “contiguous nucleotide sequence” refers to the region of the oligonucleotide which is complementary to the target nucleic acid. The term is used interchangeably herein with the term “contiguous nucleobase sequence” and the term “oligonucleotide motif sequence”. In some embodiments all the nucleotides of the oligonucleotide constitute the contiguous nucleotide sequence. In some embodiments the oligonucleotide comprises the contiguous nucleotide sequence and may optionally comprise further nucleotide(s), for example a nucleotide linker region which may be used to attach a functional group to the contiguous nucleotide sequence. The nucleotide linker region may or may not be complementary to the target nucleic acid.

Nucleotides

Nucleotides are the building blocks of oligonucleotides and polynucleotides and for the purposes of the present invention include both naturally occurring and non-naturally occurring nucleotides. In nature, nucleotides, such as DNA and RNA nucleotides comprise a ribose sugar moiety, a nucleobase moiety and one or more phosphate groups (which is absent in nucleosides). Nucleosides and nucleotides may also interchangeably be referred to as “units” or “monomers”.

Modified Nucleoside

The term “modified nucleoside” or “nucleoside modification” as used herein refers to nucleosides modified as compared to the equivalent DNA or RNA nucleoside by the introduction of one or more modifications of the sugar moiety or the (nucleo)base moiety. In a preferred embodiment the modified nucleoside comprise a modified sugar moiety. The term modified nucleoside may also be used herein interchangeably with the term “nucleoside analogue” or modified “units” or modified “monomers”.

Modified Internucleoside Linkage

The term “modified internucleoside linkage” is defined as generally understood by the skilled person as linkages other than phosphodiester (PO) linkages, that covalently couples two nucleosides together. Nucleotides with modified internucleoside linkage are also termed “modified nucleotides”. In some embodiments, the modified internucleoside linkage increases the nuclease resistance of the oligonucleotide compared to a phosphodiester linkage. For naturally occurring oligonucleotides, the internucleoside linkage includes phosphate groups creating a phosphodiester bond between adjacent nucleosides. Modified internucleoside linkages are particularly useful in stabilizing oligonucleotides for in vivo use, and may serve to protect against nuclease cleavage at regions of DNA or RNA nucleosides in the oligonucleotide of the invention, for example within the gap region of a gapmer oligonucleotide, as well as in regions of modified nucleosides.

In an embodiment, the oligonucleotide comprises one or more internucleoside linkages modified from the natural phosphodiester to a linkage that is for example more resistant to nuclease attack. Nuclease resistance may be determined by incubating the oligonucleotide in blood serum or by using a nuclease resistance assay (e.g. snake venom phosphodiesterase (SVPD)), both are well known in the art. Internucleoside linkages which are capable of enhancing the nuclease resistance of an oligonucleotide are referred to as nuclease resistant internucleoside linkages. In some embodiments at least 50% of the internucleoside linkages in the oligonucleotide, or contiguous nucleotide sequence thereof, are modified, such as at least 60%, such as at least 70%, such as at least 80 or such as at least 90% of the internucleoside linkages in the oligonucleotide, or contiguous nucleotide sequence thereof, are modified. In some embodiments all of the internucleoside linkages of the oligonucleotide, or contiguous nucleotide sequence thereof, are modified. It will be recognized that, in some embodiments the nucleosides which link the oligonucleotide of the invention to a non-nucleotide functional group, such as a conjugate, may be phosphodiester. In some embodiments all of the internucleoside linkages of the oligonucleotide, or contiguous nucleotide sequence thereof, are nuclease resistant internucleoside linkages.

Modified internucleoside linkages may be selected from the group comprising phosphorothioate, diphosphorothioate and boranophosphate. In some embodiments, the modified internucleoside linkages are compatible with the RNaseH recruitment of the oligonucleotide of the invention, for example phosphorothioate, diphosphorothioate or boranophosphate.

In some embodiments the internucleoside linkage comprises sulphur (S), such as a phosphorothioate internucleoside linkage.

A phosphorothioate internucleoside linkage is particularly useful due to nuclease resistance, beneficial pharmakokinetics and ease of manufacture. In some embodiments at least 50% of the internucleoside linkages in the oligonucleotide, or contiguous nucleotide sequence thereof, are phosphorothioate, such as at least 60%, such as at least 70%, such as at least 80 or such as at least 90% of the internucleoside linkages in the oligonucleotide, or contiguous nucleotide sequence thereof, are phosphorothioate. In some embodiments all of the internucleoside linkages of the oligonucleotide, or contiguous nucleotide sequence thereof, are phosphorothioate.

In some embodiments, the oligonucleotide comprises one or more neutral internucleoside linkage, particularly a internucleoside linkage selected from phosphotriester, methylphosphonate, MMI, amide-3, formacetal or thioformacetal.

Further internucleoside linkages are disclosed in WO2009/124238 (incorporated herein by reference). In an embodiment the internucleoside linkage is selected from linkers disclosed in WO2007/031091 (incorporated herein by reference). Particularly, the internucleoside linkage may be selected from —O—P(O) 2 —O—, —O—P(O,S)—O—, —O—P(S) 2 —O—, —S—P(O) 2 —O—, —S—P(O,S)—O—, —S—P(S) 2 —O—, —O—P(O) 2 —S—, —O—P(O,S)—S—, —S—P(O) 2 —S—, —O—PO(R H )—O—, O—PO(OCH 3 )—O—, —O—PO(NR H )—O—, —O—PO(OCH 2 CH 2 S—R)—O—, —O—PO(BH 3 )—O—, —O—PO(NHR H )—O—, —O—P(O) 2 —NR H —, —NR H —P(O) 2 —O—, —NR H —CO—O—, —NR H —CO—NR H —, and/or the internucleoside linker may be selected form the group consisting of: —O—CO—O—, —O—CO—NR H —, —NR H —CO—CH 2 —, —O—CH 2 —CO—NR H —, —O—CH 2 —CH 2 —NR H , —CO—NR H —CH 2 —, —CH 2 —NR H CO—, —O—CH 2 —CH 2 —S—, —S—CH 2 —CH 2 —O—, —S—CH 2 —CH 2 —S—, —CH 2 —SO 2 —CH 2 —, —CH 2 —CO—NR H —, —O—CH 2 —CH 2 —NR H —CO—, —CH 2 —NCH 3 —O—CH 2 —, where R H is selected from hydrogen and C1-4-alkyl.

Nuclease resistant linkages, such as phosphothioate linkages, are particularly useful in oligonucleotide regions capable of recruiting nuclease when forming a duplex with the target nucleic acid, such as region G for gapmers, or the non-modified nucleoside region of headmers and tailmers. Phosphorothioate linkages may, however, also be useful in non-nuclease recruiting regions and/or affinity enhancing regions such as regions F and F′ for gapmers, or the modified nucleoside region of headmers and tailmers.

Each of the design regions may however comprise internucleoside linkages other than phosphorothioate, such as phosphodiester linkages, in particularly in regions where modified nucleosides, such as LNA, protect the linkage against nuclease degradation. Inclusion of phosphodiester linkages, such as one or two linkages, particularly between or adjacent to modified nucleoside units (typically in the non-nuclease recruiting regions) can modify the bioavailability and/or bio-distribution of an oligonucleotide—see WO2008/113832, incorporated herein by reference.

In an embodiment all the internucleoside linkages in the oligonucleotide are phosphorothioate and/or boranophosphate linkages. Preferably, all the internucleoside linkages in the oligonucleotide are phosphorothioate linkages.

Nucleobase

The term nucleobase includes the purine (e.g. adenine and guanine) and pyrimidine (e.g. uracil, thymine and cytosine) moiety present in nucleosides and nucleotides which form hydrogen bonds in nucleic acid hybridization. In the context of the present invention the term nucleobase also encompasses modified nucleobases which may differ from naturally occurring nucleobases, but are functional during nucleic acid hybridization. In this context “nucleobase” refers to both naturally occurring nucleobases such as adenine, guanine, cytosine, thymidine, uracil, xanthine and hypoxanthine, as well as non-naturally occurring variants. Such variants are for example described in Hirao et al (2012) Accounts of Chemical Research vol 45 page 2055 and Bergstrom (2009) Current Protocols in Nucleic Acid Chemistry Suppl. 37 1.4.1.

In a some embodiments the nucleobase moiety is modified by changing the purine or pyrimidine into a modified purine or pyrimidine, such as substituted purine or substituted pyrimidine, such as a nucleobased selected from isocytosine, pseudoisocytosine, 5-methyl cytosine, 5-thiozolo-cytosine, 5-propynyl-cytosine, 5-propynyl-uracil, 5-bromouracil 5-thiazolo-uracil, 2-thio-uracil, 2′thio-thymine, inosine, diaminopurine, 6-aminopurine, 2-aminopurine, 2,6-diaminopurine and 2-chloro-6-aminopurine.

The nucleobase moieties may be indicated by the letter code for each corresponding nucleobase, e.g. A, T, G, C or U, wherein each letter may optionally include modified nucleobases of equivalent function. For example, in the exemplified oligonucleotides, the nucleobase moieties are selected from A, T, G, C, and 5-methyl cytosine. Optionally, for LNA gapmers, 5-methyl cytosine LNA nucleosides may be used.

Modified Oligonucleotide

The term modified oligonucleotide describes an oligonucleotide comprising one or more sugar-modified nucleosides and/or modified internucleoside linkages. The term chimeric” oligonucleotide is a term that has been used in the literature to describe oligonucleotides with modified nucleosides.

Complementarity

The term “complementarity” describes the capacity for Watson-Crick base-pairing of nucleosides/nucleotides. Watson-Crick base pairs are guanine (G)-cytosine (C) and adenine (A)-thymine (T)/uracil (U). It will be understood that oligonucleotides may comprise nucleosides with modified nucleobases, for example 5-methyl cytosine is often used in place of cytosine, and as such the term complementarity encompasses Watson Crick base-paring between non-modified and modified nucleobases (see for example Hirao et al (2012) Accounts of Chemical Research vol 45 page 2055 and Bergstrom (2009) Current Protocols in Nucleic Acid Chemistry Suppl. 37 1.4.1).

The term “% complementary” as used herein, refers to the number of nucleotides in percent of a contiguous nucleotide sequence in a nucleic acid molecule (e.g. oligonucleotide) which, at a given position, are complementary to (i.e. form Watson Crick base pairs with) a contiguous nucleotide sequence, at a given position of a separate nucleic acid molecule (e.g. the target nucleic acid). The percentage is calculated by counting the number of aligned bases that form pairs between the two sequences (when aligned with the target sequence 5′-3′ and the oligonucleotide sequence from 3′-5′), dividing by the total number of nucleotides in the oligonucleotide and multiplying by 100. In such a comparison a nucleobase/nucleotide which does not align (form a base pair) is termed a mismatch.

The term “fully complementary”, refers to 100% complementarity.

The following is an example of an oligonucleotide (SEQ ID NO: 5) that is fully complementary to the target nucleic acid (SEQ ID NO: 772).

Identity

The term “Identity” as used herein, refers to the number of nucleotides in percent of a contiguous nucleotide sequence in a nucleic acid molecule (e.g. oligonucleotide) which, at a given position, are identical to (i.e. in their ability to form Watson Crick base pairs with the complementary nucleoside) a contiguous nucleotide sequence, at a given position of a separate nucleic acid molecule (e.g. the target nucleic acid). The percentage is calculated by counting the number of aligned bases that are identical between the two sequences, including gaps, dividing by the total number of nucleotides in the oligonucleotide and multiplying by 100.

Percent Identity=(Matches×100)/Length of aligned region (with gaps).

Hybridization

The term “hybridizing” or “hybridizes” as used herein is to be understood as two nucleic acid strands (e.g. an oligonucleotide and a target nucleic acid) forming hydrogen bonds between base pairs on opposite strands thereby forming a duplex. The affinity of the binding between two nucleic acid strands is the strength of the hybridization. It is often described in terms of the melting temperature (T m ) defined as the temperature at which half of the oligonucleotides are duplexed with the target nucleic acid. At physiological conditions T m is not strictly proportional to the affinity (Mergny and Lacroix, 2003, Oligonucleotides 13:515-537). The standard state Gibbs free energy ΔG° is a more accurate representation of binding affinity and is related to the dissociation constant (K d ) of the reaction by ΔG°=−RT ln(K d ), where R is the gas constant and T is the absolute temperature. Therefore, a very low ΔG° of the reaction between an oligonucleotide and the target nucleic acid reflects a strong hybridization between the oligonucleotide and target nucleic acid. ΔG° is the energy associated with a reaction where aqueous concentrations are 1M, the pH is 7, and the temperature is 37° C. The hybridization of oligonucleotides to a target nucleic acid is a spontaneous reaction and for spontaneous reactions ΔG° is less than zero. ΔG° can be measured experimentally, for example, by use of the isothermal titration calorimetry (ITC) method as described in Hansen et al., 1965 , Chem. Comm. 36-38 and Holdgate et al., 2005 , Drug Discov Today . The skilled person will know that commercial equipment is available for ΔG° measurements. ΔG° can also be estimated numerically by using the nearest neighbor model as described by SantaLucia, 1998 , Proc Natl Acad Sci USA, 95: 1460-1465 using appropriately derived thermodynamic parameters described by Sugimoto et al., 1995 , Biochemistry 34:11211-11216 and McTigue et al., 2004 , Biochemistry 43:5388-5405. In order to have the possibility of modulating its intended nucleic acid target by hybridization, oligonucleotides of the present invention hybridize to a target nucleic acid with estimated ΔG° values below −10 kcal for oligonucleotides that are 10-30 nucleotides in length. In some embodiments the degree or strength of hybridization is measured by the standard state Gibbs free energy ΔG°. The oligonucleotides may hybridize to a target nucleic acid with estimated ΔG° values below the range of −10 kcal, such as below −15 kcal, such as below −20 kcal and such as below −25 kcal for oligonucleotides that are 8-30 nucleotides in length. In some embodiments the oligonucleotides hybridize to a target nucleic acid with an estimated ΔG° value of −10 to −60 kcal, such as −12 to −40, such as from −15 to −30 kcal or −16 to −27 kcal such as −18 to −25 kcal.

Target Nucleic Acid

According to the present invention, the target nucleic acid is a nucleic acid which encodes mammalian PD-L1 and may for example be a gene, a RNA, a mRNA, and pre-mRNA, a mature mRNA or a cDNA sequence. The target may therefore be referred to as a PD-L1 target nucleic acid. The oligonucleotide of the invention may for example target exon regions of a mammalian PD-L1, or may for example target intron region in the PD-L1 pre-mRNA (see Table 1).

Suitably, the target nucleic acid encodes a PD-L1 protein, in particular mammalian PD-L1, such as human PD-L1 (See for example tables 2 and 3, which provide reference to the mRNA and pre-mRNA sequences for human, monkey, and mouse PD-L1). In the context of the present invention pre-mRNA is also considered as a nucleic acid that encodes a protein.

In some embodiments, the target nucleic acid is selected from the group consisting of SEQ ID NO: 1, 2 and 3 or naturally occurring variants thereof (e.g. sequences encoding a mammalian PD-L1 protein).

If employing the oligonucleotide of the invention in research or diagnostics the target nucleic acid may be a cDNA or a synthetic nucleic acid derived from DNA or RNA.

For in vivo or in vitro application, the oligonucleotide of the invention is typically capable of inhibiting the expression of the PD-L1 target nucleic acid in a cell which is expressing the PD-L1 target nucleic acid. The contiguous sequence of nucleobases of the oligonucleotide of the invention is typically complementary to the PD-L1 target nucleic acid, as measured across the length of the oligonucleotide, optionally with the exception of one or two mismatches, and optionally excluding nucleotide based linker regions which may link the oligonucleotide to an optional functional group such as a conjugate, or other non-complementary terminal nucleotides (e.g. region D′ or D″). The target nucleic acid may, in some embodiments, be a RNA or DNA, such as a messenger RNA, such as a mature mRNA or a pre-mRNA. In some embodiments the target nucleic acid is a RNA or DNA which encodes mammalian PD-L1 protein, such as human PD-L1, e.g. the human PD-L1 premRNA sequence, such as that disclosed as SEQ ID NO 1 or the human mRNA sequence with NCBI reference number NM_014143. Further information on exemplary target nucleic acids is provided in tables 2 and 3.

Target Sequence

The term “target sequence” as used herein refers to a sequence of nucleotides present in the target nucleic acid which comprises the nucleobase sequence which is complementary to the oligonucleotide of the invention. In some embodiments, the target sequence consists of a region on the target nucleic acid which is complementary to the contiguous nucleotide sequence of the oligonucleotide of the invention. In some embodiments the target sequence is longer than the complementary sequence of a single oligonucleotide, and may, for example represent a preferred region of the target nucleic acid which may be targeted by several oligonucleotides of the invention.

The target sequence may be a sub-sequence of the target nucleic acid.

In some embodiments the sub-sequence is a sequence selected from the group consisting of a1-a149 (see tables 4). In some embodiments the sub-sequence is a sequence selected from the group consisting of a human PD-L1 mRNA exon, such as a PD-L1 human mRNA exon selected from the group consisting of e1, e2, e3, e4, e5, e6, and e7 (see table 1 above).

In some embodiments the sub-sequence is a sequence selected from the group consisting of a human PD-L1 mRNA intron, such as a PD-L1 human mRNA intron selected from the group consisting of i1, i2, i3, i4, i5 and i6 (see table 1 above).

The oligonucleotide of the invention comprises a contiguous nucleotide sequence which is complementary to or hybridizes to the target nucleic acid, such as a sub-sequence of the target nucleic acid, such as a target sequence described herein.

The oligonucleotide comprises a contiguous nucleotide sequence of at least 8 nucleotides which is complementary to or hybridizes to a target sequence present in the target nucleic acid molecule. The contiguous nucleotide sequence (and therefore the target sequence) comprises of at least 8 contiguous nucleotides, such as 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 contiguous nucleotides, such as from 12-25, such as from 14-18 contiguous nucleotides.

Target Cell

The term a “target cell” as used herein refers to a cell which is expressing the target nucleic acid. In some embodiments the target cell may be in vivo or in vitro. In some embodiments the target cell is a mammalian cell such as a rodent cell, such as a mouse cell or a rat cell, or a primate cell such as a monkey cell or a human cell.

In preferred embodiments the target cell expresses PD-L1 mRNA, such as the PD-L1 pre-mRNA or PD-L1 mature mRNA. The poly A tail of PD-L1 mRNA is typically disregarded for antisense oligonucleotide targeting.

Naturally Occurring Variant

The term “naturally occurring variant” refers to variants of PD-L1 gene or transcripts which originate from the same genetic loci as the target nucleic acid, but may differ for example, by virtue of degeneracy of the genetic code causing a multiplicity of codons encoding the same amino acid, or due to alternative splicing of pre-mRNA, or the presence of polymorphisms, such as single nucleotide polymorphisms, and allelic variants. Based on the presence of the sufficient complementary sequence to the oligonucleotide, the oligonucleotide of the invention may therefore target the target nucleic acid and naturally occurring variants thereof.

In some embodiments, the naturally occurring variants have at least 95% such as at least 98% or at least 99% homology to a mammalian PD-L1 target nucleic acid, such as a target nucleic acid selected form the group consisting of SEQ ID NO 1, 2 and 3.

Numerous single nucleotide polymorphisms are known in the PD-L1 gene, for example those disclosed in the following table (human premRNA start/reference sequence is SEQ ID NO 2)

Modulation of Expression

The term “modulation of expression” as used herein is to be understood as an overall term for an oligonucleotide's ability to alter the amount of PD-L1 when compared to the amount of PD-L1 before administration of the oligonucleotide. Alternatively modulation of expression may be determined by reference to a control experiment. It is generally understood that the control is an individual or target cell treated with a saline composition or an individual or target cell treated with a non-targeting oligonucleotide (mock). It may however also be an individual treated with the standard of care.

One type of modulation is an oligonucleotide's ability to inhibit, down-regulate, reduce, suppress, remove, stop, block, prevent, lessen, lower, avoid or terminate expression of PD-L1, e.g. by degradation of mRNA or blockage of transcription. Another type of modulation is an oligonucleotide's ability to restore, increase or enhance expression of PD-L1, e.g. by repair of splice sites or prevention of splicing or removal or blockage of inhibitory mechanisms such as microRNA repression.

High Affinity Modified Nucleosides

A high affinity modified nucleoside is a modified nucleotide which, when incorporated into the oligonucleotide enhances the affinity of the oligonucleotide for its complementary target, for example as measured by the melting temperature (T m ). A high affinity modified nucleoside of the present invention preferably result in an increase in melting temperature between +0.5 to +12° C., more preferably between +1.5 to +10° C. and most preferably between +3 to +8° C. per modified nucleoside. Numerous high affinity modified nucleosides are known in the art and include for example, many 2′ substituted nucleosides as well as locked nucleic acids (LNA) (see e.g. Freier & Altmann; Nucl. Acid Res., 1997, 25, 4429-4443 and Uhlmann; Curr. Opinion in Drug Development, 2000, 3(2), 293-213).

Sugar Modifications

The oligomer of the invention may comprise one or more nucleosides which have a modified sugar moiety, i.e. a modification of the sugar moiety when compared to the ribose sugar moiety found in DNA and RNA.

Numerous nucleosides with modification of the ribose sugar moiety have been made, primarily with the aim of improving certain properties of oligonucleotides, such as affinity and/or nuclease resistance.

Such modifications include those where the ribose ring structure is modified, e.g. by replacement with a hexose ring (HNA), or a bicyclic ring, which typically have a biradicle bridge between the C2 and C4 carbons on the ribose ring (LNA), or an unlinked ribose ring which typically lacks a bond between the C2 and C3 carbons (e.g. UNA). Other sugar modified nucleosides include, for example, bicyclohexose nucleic acids (WO2011/017521) or tricyclic nucleic acids (WO2013/154798). Modified nucleosides also include nucleosides where the sugar moiety is replaced with a non-sugar moiety, for example in the case of peptide nucleic acids (PNA), or morpholino nucleic acids.

Sugar modifications also include modifications made via altering the substituent groups on the ribose ring to groups other than hydrogen, or the 2′-OH group naturally found in DNA and RNA nucleosides. Substituents may, for example be introduced at the 2′, 3′, 4′ or 5′ positions. Nucleosides with modified sugar moieties also include 2′ modified nucleosides, such as 2′ substituted nucleosides. Indeed, much focus has been spent on developing 2′ substituted nucleosides, and numerous 2′ substituted nucleosides have been found to have beneficial properties when incorporated into oligonucleotides, such as enhanced nucleoside resistance and enhanced affinity.

2′ Modified Nucleosides.

A 2′ sugar modified nucleoside is a nucleoside which has a substituent other than H or —OH at the 2′ position (2′ substituted nucleoside) or comprises a 2′ linked biradicle, and includes 2′ substituted nucleosides and LNA (2′-4′ biradicle bridged) nucleosides. For example, the 2′ modified sugar may provide enhanced binding affinity and/or increased nuclease resistance to the oligonucleotide. Examples of 2′ substituted modified nucleosides are 2′-O-alkyl-RNA, 2′-O-methyl-RNA, 2′-alkoxy-RNA, 2′-O-methoxyethyl-RNA (MOE), 2′-amino-DNA, 2′-Fluoro-RNA, and 2′-F-ANA nucleoside. For further examples, please see e.g. Freier & Altmann; Nucl. Acid Res., 1997, 25, 4429-4443 and Uhlmann; Curr. Opinion in Drug Development, 2000, 3(2), 293-213, and Deleavey and Damha, Chemistry and Biology 2012, 19, 937. Below are illustrations of some 2′ substituted modified nucleosides.

Locked Nucleic Acid Nucleosides (LNA).

LNA nucleosides are modified nucleosides which comprise a linker group (referred to as a biradicle or a bridge) between C2′ and C4′ of the ribose sugar ring of a nucleotide. These nucleosides are also termed bridged nucleic acid or bicyclic nucleic acid (BNA) in the literature. In some embodiments, the modified nucleoside or the LNA nucleosides of the oligomer of the invention has a general structure of the formula I or II:

wherein W is selected from —O—, —S—, —N(R a )—, —C(R a R b )—, such as, in some embodiments —O—;

B designates a nucleobase or modified nucleobase moiety;

Z designates an internucleoside linkage to an adjacent nucleoside, or a 5′-terminal group;

Z* designates an internucleoside linkage to an adjacent nucleoside, or a 3′-terminal group;

X designates a group selected from the list consisting of —C(R a R b )—, —C(R a )═C(R b )—, —C(R a )═N—, —O—, —Si(R a ) 2 —, —S—, —SO 2 —, —N(R a )—, and >C═Z

In some embodiments, X is selected from the group consisting of: —O—, —S—, NH—, NR a R b , —CH 2 —, CR a R b , —C(═CH 2 )—, and —C(═CR a R b )— In some embodiments, X is —O—

Y designates a group selected from the group consisting of —C(R a R b )—, —C(R a )═C(R b )—, —C(R a )═N—, —O—, —Si(R a ) 2 —, —S—, —SO 2 —, —N(R a )—, and >C═Z

In some embodiments, Y is selected from the group consisting of: —CH 2 —, —C(R a R b )—, —CH 2 CH 2 —, —C(R a R b )—C(R a R b )—, —CH 2 CH 2 CH 2 —, —C(R a R b )C(R a R b )C(R a R b )—, —C(R a )═C(R b )—, and —C(R a )═N— In some embodiments, Y is selected from the group consisting of: —CH 2 —, —CHR a —, —CHCH 3 —, CR a R b —

or —X—Y— together designate a bivalent linker group (also referred to as a radicle) together designate a bivalent linker group consisting of 1, 2, 3 or 4 groups/atoms selected from the group consisting of —C(R a R b )—, —C(R a )═C(R b )—, —C(R a )═N—, —O—, —Si(R a ) 2 —, —S—, —SO 2 —, —N(R a )—, and >C═Z,

In some embodiments, —X—Y— designates a biradicle selected from the groups consisting of: —X—CH 2 —, —X—CR a R b —, —X—CHR a —, —X—C(HCH 3 )—, —O—Y—, —O—CH 2 —, —S—CH 2 —, —NH—CH 2 —, —O—CHCH 3 —, —CH 2 —O—CH 2 , —O—CH(CH 3 CH 3 )—, —O—CH 2 —CH 2 —, OCH 2 —CH 2 —CH 2 —, —O—CH 2 OCH 2 —, —O—NCH 2 —, —C(═CH 2 )—CH 2 —, —NR a —CH 2 —, NO—CH 2 , —S—CR a R b — and —S—CHR a —. In some embodiments —X—Y— designates —O—CH 2 — or —O—CH(CH 3 )—.

wherein Z is selected from —O—, —S—, and —N(R a )—,

and R a and, when present R b , each is independently selected from hydrogen, optionally substituted C 1-6 -alkyl, optionally substituted C 2-6 -alkenyl, optionally substituted C 2-6 -alkynyl, hydroxy, optionally substituted C 1-6 -alkoxy, C 2-6 -alkoxyalkyl, C 2-6 -alkenyloxy, carboxy, C 1-6 -alkoxycarbonyl, C 1-6 -alkylcarbonyl, formyl, aryl, aryloxy-carbonyl, aryloxy, arylcarbonyl, heteroaryl, heteroaryloxy-carbonyl, heteroaryloxy, heteroarylcarbonyl, amino, mono- and di(C 1-6 -alkyl)amino, carbamoyl, mono- and di(C 1-6 -alkyl)-amino-carbonyl, amino-C 1-6 -alkyl-aminocarbonyl, mono- and di(C 1-6 -alkyl)amino-C 1-6 -alkyl-aminocarbonyl, C 1-6 -alkyl-carbonylamino, carbamido, C 1-6 -alkanoyloxy, sulphono, C 1-6 -alkylsulphonyloxy, nitro, azido, sulphanyl, C 1-6 -alkylthio, halogen, where aryl and heteroaryl may be optionally substituted and where two geminal substituents R a and R b together may designate optionally substituted methylene (═CH 2 ), wherein for all chiral centers, asymmetric groups may be found in either R or S orientation.

wherein R 1 , R 2 , R 3 , R 5 and R 5* are independently selected from the group consisting of: hydrogen, optionally substituted C 1-6 -alkyl, optionally substituted C 2-6 -alkenyl, optionally substituted C 2-6 -alkynyl, hydroxy, C 1-6 -alkoxy, C 2-6 -alkoxyalkyl, C 2-6 -alkenyloxy, carboxy, C 1-6 -alkoxycarbonyl, C 1-6 -alkylcarbonyl, formyl, aryl, aryloxy-carbonyl, aryloxy, arylcarbonyl, heteroaryl, heteroaryloxy-carbonyl, heteroaryloxy, heteroarylcarbonyl, amino, mono- and di(C 1-6 -alkyl)amino, carbamoyl, mono- and di(C 1-6 -alkyl)-amino-carbonyl, amino-C 1-6 -alkyl-aminocarbonyl, mono- and di(C 1-6 -alkyl)amino-C 1-6 -alkyl-aminocarbonyl, C 1-6 -alkyl-carbonylamino, carbamido, C 1-6 -alkanoyloxy, sulphono, C 1-6 -alkylsulphonyloxy, nitro, azido, sulphanyl, C 1-6 -alkylthio, halogen, where aryl and heteroaryl may be optionally substituted, and where two geminal substituents together may designate oxo, thioxo, imino, or optionally substituted methylene.

In some embodiments R 1 , R 2 , R 3 , R 5 and R 5* are independently selected from C 1-6 alkyl, such as methyl, and hydrogen. In some embodiments R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. In some embodiments R 1 , R 2 , R 3 , are all hydrogen, and either R 5 and R 5* is also hydrogen and the other of R 5 and R 5* is other than hydrogen, such as C 1-6 alkyl such as methyl. In some embodiments, R a is either hydrogen or methyl. In some embodiments, when present, R b is either hydrogen or methyl. In some embodiments, one or both of R a and R b is hydrogen In some embodiments, one of R a and R b is hydrogen and the other is other than hydrogen In some embodiments, one of R a and R b is methyl and the other is hydrogen In some embodiments, both of R a and R b are methyl.

In some embodiments, the biradicle —X—Y— is —O—CH 2 —, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such LNA nucleosides are disclosed in WO99/014226, WO00/66604, WO98/039352 and WO2004/046160 which are all hereby incorporated by reference, and include what are commonly known as beta-D-oxy LNA and alpha-L-oxy LNA nucleosides.

In some embodiments, the biradicle —X—Y— is —S—CH 2 —, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such thio LNA nucleosides are disclosed in WO99/014226 and WO2004/046160 which are hereby incorporated by reference.

In some embodiments, the biradicle —X—Y— is —NH—CH 2 —, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such amino LNA nucleosides are disclosed in WO99/014226 and WO2004/046160 which are hereby incorporated by reference.

In some embodiments, the biradicle —X—Y— is —O—CH 2 —CH 2 — or —O—CH 2 —CH 2 —CH 2 —, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such LNA nucleosides are disclosed in WO00/047599 and Morita et al, Bioorganic & Med. Chem. Lett. 12 73-76, which are hereby incorporated by reference, and include what are commonly known as 2′-O-4′C-ethylene bridged nucleic acids (ENA).

In some embodiments, the biradicle —X—Y— is —O—CH 2 —, W is O, and all of R 1 , R 2 , R 3 , and one of R 5 and R 5* are hydrogen, and the other of R 5 and R 5* is other than hydrogen such as C 1-6 alkyl, such as methyl. Such 5′ substituted LNA nucleosides are disclosed in WO2007/134181 which is hereby incorporated by reference.

In some embodiments, the biradicle —X—Y— is —O—CR a R b —, wherein one or both of R a and R b are other than hydrogen, such as methyl, W is O, and all of R 1 , R 2 , R 3 , and one of R 5 and R 5* are hydrogen, and the other of R 5 and R 5* is other than hydrogen such as C 1-6 alkyl, such as methyl.

Such bis modified LNA nucleosides are disclosed in WO2010/077578 which is hereby incorporated by reference.

In some embodiments, the biradicle —X—Y— designate the bivalent linker group —O—CH(CH 2 OCH 3 )— (2′ O-methoxyethyl bicyclic nucleic acid—Seth at al., 2010, J. Org. Chem. Vol 75(5) pp. 1569-81). In some embodiments, the biradicle —X—Y— designate the bivalent linker group —O—CH(CH 2 CH 3 )— (2′O-ethyl bicyclic nucleic acid—Seth at al., 2010, J. Org. Chem. Vol 75(5) pp. 1569-81). In some embodiments, the biradicle —X—Y— is —O—CHR a —, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such 6′ substituted LNA nucleosides are disclosed in WO10036698 and WO07090071 which are both hereby incorporated by reference.

In some embodiments, the biradicle —X—Y— is —O—CH(CH 2 OCH 3 )—, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such LNA nucleosides are also known as cyclic MOEs in the art (cMOE) and are disclosed in WO07090071.

In some embodiments, the biradicle —X—Y— designate the bivalent linker group —O—CH(CH 3 )—. —in either the R- or S-configuration. In some embodiments, the biradicle —X—Y— together designate the bivalent linker group —O—CH 2 —O—CH 2 — (Seth at al., 2010, J. Org. Chem). In some embodiments, the biradicle —X—Y— is —O—CH(CH 3 )—, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such 6′ methyl LNA nucleosides are also known as cET nucleosides in the art, and may be either (S)cET or (R)cET stereoisomers, as disclosed in WO07090071 (beta-D) and WO2010/036698 (alpha-L) which are both hereby incorporated by reference).

In some embodiments, the biradicle —X—Y— is —O—CR a R b —, wherein in neither R a or R b is hydrogen, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. In some embodiments, R a and R b are both methyl. Such 6′ di-substituted LNA nucleosides are disclosed in WO 2009006478 which is hereby incorporated by reference.

In some embodiments, the biradicle —X—Y— is —S—CHR a —, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such 6′ substituted thio LNA nucleosides are disclosed in WO11156202 which is hereby incorporated by reference. In some 6′ substituted thio LNA embodiments R a is methyl.

In some embodiments, the biradicle —X—Y— is —C(═CH 2 )—C(R a R b )—, such as —C(═CH 2 )—CH 2 —, or —C(═CH 2 )—CH(CH 3 )—W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. Such vinyl carbo LNA nucleosides are disclosed in WO08154401 and WO09067647 which are both hereby incorporated by reference.

In some embodiments the biradicle —X—Y— is —N(—OR a )—, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. In some embodiments R a is C 1-6 alkyl such as methyl. Such LNA nucleosides are also known as N substituted LNAs and are disclosed in WO2008/150729, which is hereby incorporated by reference. In some embodiments, the biradicle —X—Y— together designate the bivalent linker group —O—NR a —CH 3 — (Seth at al., 2010, J. Org. Chem). In some embodiments the biradicle —X—Y— is —N(R a )—, W is O, and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. In some embodiments R a is C 1-6 alkyl such as methyl.

In some embodiments, one or both of R 5 and R 5* is hydrogen and, when substituted the other of R 5 and R 5* is C 1-6 alkyl such as methyl. In such an embodiment, R 1 , R 2 , R 3 , may all be hydrogen, and the biradicle —X—Y— may be selected from —O—CH 2 — or —O—C(HCR a )—, such as —O—C(HCH3)—.

In some embodiments, the biradicle is —CR a R b —O—CR a R b —, such as CH 2 —O—CH 2 —, W is O and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. In some embodiments R a is C 1-6 alkyl such as methyl. Such LNA nucleosides are also known as conformationally restricted nucleotides (CRNs) and are disclosed in WO2013036868 which is hereby incorporated by reference.

In some embodiments, the biradicle is —O—CR a R b —O—CR a R b —, such as O—CH 2 —O—CH 2 —, W is O and all of R 1 , R 2 , R 3 , R 5 and R 5* are all hydrogen. In some embodiments R a is C 1-6 alkyl such as methyl. Such LNA nucleosides are also known as COC nucleotides and are disclosed in Mitsuoka et al., Nucleic Acids Research 2009 37(4), 1225-1238, which is hereby incorporated by reference.

It will be recognized than, unless specified, the LNA nucleosides may be in the beta-D or alpha-L stereoisoform.

Certain examples of LNA nucleosides are presented in Scheme 1.

As illustrated in the examples, in some embodiments of the invention the LNA nucleosides in the oligonucleotides are beta-D-oxy-LNA nucleosides.

Nuclease Mediated Degradation

Nuclease mediated degradation refers to an oligonucleotide capable of mediating degradation of a complementary nucleotide sequence when forming a duplex with such a sequence.

In some embodiments, the oligonucleotide may function via nuclease mediated degradation of the target nucleic acid, where the oligonucleotides of the invention are capable of recruiting a nuclease, particularly and endonuclease, preferably endoribonuclease (RNase), such as RNase H. Examples of oligonucleotide designs which operate via nuclease mediated mechanisms are oligonucleotides which typically comprise a region of at least 5 or 6 DNA nucleosides and are flanked on one side or both sides by affinity enhancing nucleosides, for example gapmers, headmers and tailmers.

RNase H Activity and Recruitment

The RNase H activity of an antisense oligonucleotide refers to its ability to recruit RNase H when in a duplex with a complementary RNA molecule. WO01/23613 provides in vitro methods for determining RNaseH activity, which may be used to determine the ability to recruit RNaseH. Typically an oligonucleotide is deemed capable of recruiting RNase H if it, when provided with a complementary target nucleic acid sequence, has an initial rate, as measured in pmol/l/min, of at least 5%, such as at least 10% or more than 20% of the of the initial rate determined when using a oligonucleotide having the same base sequence as the modified oligonucleotide being tested, but containing only DNA monomers with phosphorothioate linkages between all monomers in the oligonucleotide, and using the methodology provided by Example 91-95 of WO01/23613 (hereby incorporated by reference).

Gapmer

The term gapmer as used herein refers to an antisense oligonucleotide which comprises a region of RNase H recruiting oligonucleotides (gap) which is flanked 5′ and 3′ by regions which comprise one or more affinity enhancing modified nucleosides (flanks or wings). Various gapmer designs are described herein and a characterized by their ability to recruit RNaseH. Headmers and tailmers are oligonucleotides capable of recruiting RNase H where one of the flanks is missing, i.e. only one of the ends of the oligonucleotide comprises affinity enhancing modified nucleosides. For headmers the 3′ flank is missing (i.e. the 5′ flank comprises affinity enhancing modified nucleosides) and for tailmers the 5′ flank is missing (i.e. the 3′ flank comprises affinity enhancing modified nucleosides).

LNA Gapmer

The term LNA gapmer is a gapmer oligonucleotide wherein at least one of the affinity enhancing modified nucleosides is an LNA nucleoside.

Mixed Wing Gapmer

The term mixed wing gapmer or mixed flank gapmer refers to a LNA gapmer wherein at least one of the flank regions comprise at least one LNA nucleoside and at least one non-LNA modified nucleoside, such as at least one 2′ substituted modified nucleoside, such as, for example, 2′-O-alkyl-RNA, 2′-O-methyl-RNA, 2′-alkoxy-RNA, 2′-O-methoxyethyl-RNA (MOE), 2′-amino-DNA, 2′-Fluoro-RNA and 2′-F-ANA nucleoside(s). In some embodiments the mixed wing gapmer has one flank which comprises only LNA nucleosides (e.g. 5′ or 3′) and the other flank (3′ or 5′ respectfully) comprises 2′ substituted modified nucleoside(s) and optionally LNA nucleosides.

Gapbreaker

The term “gapbreaker oligonucleotide” is used in relation to a gapmer capable of maintaining RNAseH recruitment even though the gap region is disrupted by a non-RNaseH recruiting nucleoside (a gap-breaker nucleoside, E) such that the gap region comprise less than 5 consecutive DNA nucleosides. Non-RNaseH recruiting nucleosides are for example nucleosides in the 3′ endo conformation, such as LNA's where the bridge between C2′ and C4′ of the ribose sugar ring of a nucleoside is in the beta conformation, such as beta-D-oxy LNA or ScET nucleoside. The ability of gapbreaker oligonucleotide to recruit RNaseH is typically sequence or even compound specific—see Rukov et al. 2015 Nucl. Acids Res. Vol. 43 pp. 8476-8487, which discloses “gapbreaker” oligonucleotides which recruit RNaseH which in some instances provide a more specific cleavage of the target RNA.

In some embodiments, the oligonucleotide of the invention is a gapbreaker oligonucleotide. In some embodiments the gapbreaker oligonucleotide comprise a 5′-flank (F), a gap (G) and a 3′-flank (F′), wherein the gap is disrupted by a non-RNaseH recruiting nucleoside (a gap-breaker nucleoside, E) such that the gap contain at least 3 or 4 consecutive DNA nucleosides. In some embodiments the gapbreaker nucleoside (E) is an LNA nucleoside where the bridge between C2′ and C4′ of the ribose sugar ring of a nucleoside is in the beta conformation and is placed within the gap region such that the gap-breaker LNA nucleoside is flanked 5′ and 3′ by at least 3 (5′) and 3 (3′) or at least 3 (5′) and 4 (3′) or at least 4(5′) and 3(3′) DNA nucleosides, and wherein the oligonucleotide is capable of recruiting RNaseH.

The gapbreaker oligonucleotide can be represented by the following formulae:

F-G-E-G-F′; in particular F 1-7 -G 3-4 -E 1 -G 3-4 -F′ 1-7

D′-F-G-F′, in particular D′ 1-3 -F 1-7 -G 3-4 -E 1 -G 3-4 -F′ 1-7

F-G-F′-D″, in particular F 1-7 -G 3-4 -E 1 -G 3-4 -F′ 1-7 -D″ 1-3

D′-F-G-F′-D″, in particular D′ 1-3 -F 1-7 -G 3-4 -E 1 -G 3-4 -F′ 1-7 -D″ 1-3

Where region D′ and D″ are as described in the section “Gapmer design”.

In some embodiments the gapbreaker nucleoside (E) is a beta-D-oxy LNA or ScET or another beta-LNA nucleosides shown in Scheme 1).

Conjugate

The term conjugate as used herein refers to an oligonucleotide which is covalently linked to a non-nucleotide moiety (conjugate moiety or region C or third region), also termed a oligonucleotide conjugate.

Conjugation of the oligonucleotides of the invention to one or more non-nucleotide moieties may improve the pharmacology of the oligonucleotide, e.g. by affecting the activity, cellular distribution, cellular uptake or stability of the oligonucleotide. In some embodiments the conjugate moiety targets the oligonucleotide to the liver. A the same time the conjugate serve to reduce activity of the oligonucleotide in non-target cell types, tissues or organs, e.g. off target activity or activity in non-target cell types, tissues or organs. In one embodiment of the invention the oligonucleotide conjugate of the invention display improved inhibition of PD-L1 in the target cell when compared to an unconjugated oligonucleotide. In another embodiment the oligonucleotide conjugate of the invention has improved cellular distribution between liver and other organs, such as spleen or kidney (i.e. more conjugated oligonucleotide goes to the liver than the spleen or kidney) when compared to an unconjugated oligonucleotide. In another embodiment the oligonucleotide conjugate of the invention show improved cellular uptake into the liver of the conjugate oligonucleotide when compared to an unconjugated oligonucleotide.

WO 93/07883 and WO2013/033230 provides suitable conjugate moieties, which are hereby incorporated by reference. Further suitable conjugate moieties are those capable of binding to the asialoglycoprotein receptor (ASGPr). In particular tri-valent N-acetylgalactosamine conjugate moieties are suitable for binding to the ASGPr, see for example WO 2014/076196, WO 2014/207232 and WO 2014/179620 (hereby incorporated by reference). The conjugate moiety is essentially the part of the antisense oligonucleotides conjugates which is not composed of nucleic acids.

Oligonucleotide conjugates and their synthesis has also been reported in comprehensive reviews by Manoharan in Antisense Drug Technology, Principles, Strategies, and Applications, S. T. Crooke, ed., Ch. 16, Marcel Dekker, Inc., 2001 and Manoharan, Antisense and Nucleic Acid Drug Development, 2002, 12, 103, each of which is incorporated herein by reference in its entirety.

In an embodiment, the non-nucleotide moiety (conjugate moiety) is selected from the group consisting of carbohydrates, cell surface receptor ligands, drug substances, hormones, lipophilic substances, polymers, proteins, peptides, toxins (e.g. bacterial toxins), vitamins, viral proteins (e.g. capsids) or combinations thereof.

Linkers

A linkage or linker is a connection between two atoms that links one chemical group or segment of interest to another chemical group or segment of interest via one or more covalent bonds. Conjugate moieties can be attached to the oligonucleotide directly or through a linking moiety (e.g. linker or tether). Linkers serve to covalently connect a third region, e.g. a conjugate moiety (Region C), to a first region, e.g. an oligonucleotide or contiguous nucleotide sequence complementary to the target nucleic acid (region A).

In some embodiments of the invention the conjugate or oligonucleotide conjugate of the invention may optionally, comprise a linker region (second region or region B and/or region Y) which is positioned between the oligonucleotide or contiguous nucleotide sequence complementary to the target nucleic acid (region A or first region) and the conjugate moiety (region C or third region).

Region B refers to biocleavable linkers comprising or consisting of a physiologically labile bond that is cleavable under conditions normally encountered or analogous to those encountered within a mammalian body. Conditions under which physiologically labile linkers undergo chemical transformation (e.g., cleavage) include chemical conditions such as pH, temperature, oxidative or reductive conditions or agents, and salt concentration found in or analogous to those encountered in mammalian cells. Mammalian intracellular conditions also include the presence of enzymatic activity normally present in a mammalian cell such as from proteolytic enzymes or hydrolytic enzymes or nucleases. In one embodiment the biocleavable linker is susceptible to S1 nuclease cleavage. In a preferred embodiment the nuclease susceptible linker comprises between 1 and 10 nucleosides, such as 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 nucleosides, more preferably between 2 and 6 nucleosides and most preferably between 2 and 4 linked nucleosides comprising at least two consecutive phosphodiester linkages, such as at least 3 or 4 or 5 consecutive phosphodiester linkages. Preferably the nucleosides are DNA or RNA. Phosphodiester containing biocleavable linkers are described in more detail in WO 2014/076195 (hereby incorporated by reference).

Region Y refers to linkers that are not necessarily biocleavable but primarily serve to covalently connect a conjugate moiety (region C or third region), to an oligonucleotide or contiguous nucleotide sequence complementary to the target nucleic acid (region A or first region). The region Y linkers may comprise a chain structure or an oligomer of repeating units such as ethylene glycol, amino acid units or amino alkyl groups The oligonucleotide conjugates of the present invention can be constructed of the following regional elements A-C, A-B-C, A-B-Y-C, A-Y-B-C or A-Y-C. In some embodiments the linker (region Y) is an amino alkyl, such as a C2-C36 amino alkyl group, including, for example C6 to C12 amino alkyl groups. In a preferred embodiment the linker (region Y) is a C6 amino alkyl group.

Treatment

The term ‘treatment’ as used herein refers to both treatment of an existing disease (e.g. a disease or disorder as herein referred to), or prevention of a disease, i.e. prophylaxis. It will therefore be recognized that treatment as referred to herein may, in some embodiments, be prophylactic.

Restoration of Immune Response Against Pathogens

The immune response is divided into the innate and adaptive immune response. The innate immune system provides an immediate, but non-specific response. The adaptive immune response is activated by innate immune response and is highly specific to a particular pathogen. Upon presentation of a pathogen-derived antigen on the surface of antigen-presenting cells, immune cells of the adaptive immune response (i.e. T and B lymphocytes) are activated through their antigen-specific receptors leading to a pathogenic-specific immune response and development of immunological memory. Chronic viral infections, such as HBV and HCV, are associated with T cell exhaustion characterized by unresponsiveness of the viral-specific T cells. T cell exhaustion is well studied, for a review see for example Yi et al 2010 Immunology 129, 474-481. Chronic viral infections are also associated with reduced function of NK cells that are innate immune cells. Enhancing viral immune response is important for clearance of chronic infection. Restoration of immune response against pathogens, mediated by T cells and NK cells, can be assessed by measurement of proliferation, cytokine secretion and cytolytic function (Dolina et al. 2013 Molecular Therapy-Nucleic Acids, 2 e72 and Example 6 herein).

The present invention relates to the use of antisense oligonucleotides and conjugates thereof and pharmaceutical compositions comprising these to restore immune response against pathogens that have infected an animal, in particular a human. The antisense oligonucleotide conjugates of the present invention are particular useful against pathogens that have infected the liver, in particular chronic liver infections like HBV. The conjugates allow targeted distribution of the oligonucleotides and prevents systemic knockdown of the target nucleic acid.

The Oligonucleotides of the Invention

The invention relates to oligonucleotides capable of modulating expression of PD-L1. The modulation is may achieved by hybridizing to a target nucleic acid encoding PD-L1 or which is involved in the regulation of PD-L1. The target nucleic acid may be a mammalian PD-L1 sequence, such as a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2 and/or SEQ ID NO: 3. The target nucleic acid may be a pre-mRNA, an mRNA or any RNA sequence expressed from a mammalian cell that supports the expression or regulation of PD-L1.

The oligonucleotide of the invention is an antisense oligonucleotide which targets PD-L1.

In one aspect of the invention the oligonucleotides of the invention are conjugated to a conjugate moiety, in particular an asialoglycoprotein receptor targeting conjugate moiety.

In some embodiments the antisense oligonucleotide of the invention is capable of modulating the expression of the target by inhibiting or down-regulating it. Preferably, such modulation produces an inhibition of expression of at least 20% compared to the normal expression level of the target, more preferably at least 30%, 40%, 50%, 60%, 70%, 80%, or 90% inhibition compared to the normal expression level of the target. Preferably, such modulation produces an inhibition of expression of at least 20% compared to the expression level when the cell or organism is challenged by an infectious agent, or treated with an agent simulating the challenge by an infectious agent (eg poly I:C or LPS), more preferably at least 30%, 40%, 50%, 60%, 70%, 80%, or 90% inhibition compared to the expression level when the cell or organism is challenged by an infectious agent, or treated with an agent simulating the challenge by an infectious agent (eg poly I:C or LPS). In some embodiments oligonucleotides of the invention may be capable of inhibiting expression levels of PD-L1 mRNA by at least 60% or 70% in vitro using KARPAS-299 or THP1 cells. In some embodiments compounds of the invention may be capable of inhibiting expression levels of PD-L1 protein by at least 50% in vitro using KARPAS-299 or THP1 cells. Suitably, the examples provide assays which may be used to measure PD-L1 RNA (e.g. example 1). The target modulation is triggered by the hybridization between a contiguous nucleotide sequence of the oligonucleotide and the target nucleic acid. In some embodiments the oligonucleotide of the invention comprises mismatches between the oligonucleotide and the target nucleic acid. Despite mismatches, hybridization to the target nucleic acid may still be sufficient to show a desired modulation of PD-L1 expression. Reduced binding affinity resulting from mismatches may advantageously be compensated by increased number of nucleotides in the oligonucleotide and/or an increased number of modified nucleosides capable of increasing the binding affinity to the target, such as 2′ modified nucleosides, including LNA, present within the oligonucleotide sequence.

In some embodiments the antisense oligonucleotide of the invention is capable of restoring pathogen-specific T cells. In some embodiments, oligonucleotides of the invention are capable of increasing the pathogen-specific T cells by at least 40%, 50%, 60% or 70% when compared to untreated controls or controls treated with standard of care. In one embodiment the antisense oligonucleotide or conjugate of the invention is capable increasing HBV-specific T cells when compared to untreated controls or controls treated with standard of care. Suitably, the examples provide assays which may be used to measure the HBV-specific T cells (e.g. T cell proliferation, cytokine secretion and cytolytic activity). In another embodiment the antisense oligonucleotide or conjugate of the invention is capable increasing HCV-specific T cells when compared to untreated controls or controls treated with standard of care. In another embodiment the antisense oligonucleotide or conjugate of the invention is capable increasing HDV-specific T cells when compared to untreated controls or controls treated with standard of care.

In some embodiments the antisense oligonucleotide of the invention is capable reducing HBsAg levels in an animal or human. In some embodiments, oligonucleotides of the invention are capable of reducing the HBsAg levels by at least 40%, 50%, 60% or 70%, more preferably by at least 80%, 90% or 95% when compared to the level prior to treatment. Most preferably oligonucleotides of the invention are capable of achieving seroconversion of HBsAg in an animal or human infected with HBV.

An aspect of the present invention relates to an antisense oligonucleotide which comprises a contiguous nucleotide sequence of 10 to 30 nucleotides in length with at least 90% complementarity to a PD-L1 target nucleic acid.

In some embodiments, the oligonucleotide comprises a contiguous sequence which is at least 90% complementary, such as at least 91%, such as at least 92%, such as at least 93%, such as at least 94%, such as at least 95%, such as at least 96%, such as at least 97%, such as at least 98%, or 100% complementary with a region of the target nucleic acid.

In a preferred embodiment the oligonucleotide of the invention, or contiguous nucleotide sequence thereof is fully complementary (100% complementary) to a region of the target nucleic acid, or in some embodiments may comprise one or two mismatches between the oligonucleotide and the target nucleic acid.

In some embodiments the oligonucleotide comprises a contiguous nucleotide sequence of 10 to 30 nucleotides in length with at least 90% complementary, such as fully (or 100%) complementary, to a region target nucleic acid region present in SEQ ID NO: 1 or SEQ ID NO: 2. In some embodiments the oligonucleotide sequence is 100% complementary to a corresponding target nucleic acid region present SEQ ID NO: 1 and SEQ ID NO: 2. In some embodiments the oligonucleotide sequence is 100% complementary to a corresponding target nucleic acid region present SEQ ID NO: 1 and SEQ ID NO: 3.

In some embodiments, the oligonucleotide or oligonucleotide conjugate comprises a contiguous nucleotide sequence of 10 to 30 nucleotides in length with at least 90% complementary, such as 100% complementarity, to a corresponding target nucleic acid region wherein the contiguous nucleotide sequence is complementary to a sub-sequence of the target nucleic acid selected from the group consisting of position 371-3068, 5467-12107 and 15317-19511 on SEQ ID NO: 1. In a further embodiment the sub-sequence of the target nucleic acid is selected from the group consisting of position 371-510, 822-1090, 1992-3068, 5467-5606, 6470-12107, 15317-15720, 15317-18083, 18881-19494 and 1881-19494 on SEQ ID NO: 1. In a preferred embodiment the sub-sequence of the target nucleic acid is selected from the group consisting of position 7300-7333, 8028-8072, 9812-9859, 11787-11873 and 15690-15735 on SEQ ID NO: 1.

In some embodiments, the oligonucleotide or oligonucleotide conjugate comprises a contiguous nucleotide sequence of 10 to 30 nucleotides in length with at least 90% complementary, such as 100% complementarity, to a corresponding target nucleic acid region present in SEQ ID NO: 1, wherein the target nucleic acid region is selected from the group consisting of region a1 to a449 in table 4.

In some embodiment the oligonucleotide or contiguous nucleotide sequence is complementary to a region of the target nucleic acid, wherein the target nucleic acid region is selected from the group consisting of a7, a26, a43, a119, a142, a159, a160, a163, a169, a178, a179, a180, a189, a201, a202, a204, a214, a221, a224, a226, a243, a254, a258, 269, a274, a350, a360, a364, a365, a370, a372, a381, a383, a386, a389, a400, a427, a435 and a438.

In a preferred embodiment the oligonucleotide or contiguous nucleotide sequence is complementary to a region of the target nucleic acid, wherein the target nucleic acid region is selected from the group consisting of a160, a180, a221, a269 and a360.

In some embodiments, the oligonucleotide of the invention comprises or consists of 8 to 35 nucleotides in length, such as from 9 to 30, such as 10 to 22, such as from 11 to 20, such as from 12 to 18, such as from 13 to 17 or 14 to 16 contiguous nucleotides in length. In a preferred embodiment, the oligonucleotide comprises or consists of 16 to 20 nucleotides in length. It is to be understood that any range given herein includes the range endpoints. Accordingly, if an oligonucleotide is said to include from 10 to 30 nucleotides, both 10 and 30 nucleotides are included.

In some embodiments, the contiguous nucleotide sequence comprises or consists of 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 contiguous nucleotides in length. In a preferred embodiment, the oligonucleotide comprises or consists of 16, 17, 18, 19 or 20 nucleotides in length.

In some embodiments, the oligonucleotide or contiguous nucleotide sequence comprises or consists of a sequence selected from the group consisting of sequences listed in table 5.

In some embodiments, the antisense oligonucleotide or contiguous nucleotide sequence comprises or consists of 10 to 30 nucleotides in length with at least 90% identity, preferably 100% identity, to a sequence selected from the group consisting of SEQ ID NO: 5 to 743 (see motif sequences listed in table 5).

In some embodiments, the antisense oligonucleotide or contiguous nucleotide sequence comprises or consists of 10 to 30 nucleotides in length with at least 90% identity, preferably 100% identity, to a sequence selected from the group consisting of SEQ ID NO: 5 to 743 and 771.

In some embodiments, the antisense oligonucleotide or contiguous nucleotide sequence comprises or consists of 10 to 30 nucleotides in length with at least 90% identity, preferably 100% identity, to a sequence selected from the group consisting of SEQ ID NO: 6, 8, 9, 13, 41, 42, 58, 77, 92, 111, 128, 151, 164, 166, 169, 171, 222, 233, 245, 246, 250, 251, 252, 256, 272, 273, 287, 292, 303, 314, 318, 320, 324, 336, 342, 343, 344, 345, 346, 349, 359, 360, 374, 408, 409, 415, 417, 424, 429, 430, 458, 464, 466, 474, 490, 493, 512, 519, 519, 529, 533, 534, 547, 566, 567, 578, 582, 601, 619, 620, 636, 637, 638, 640, 645, 650, 651, 652, 653, 658, 659, 660, 665, 678, 679, 680, 682, 683, 684, 687, 694, 706, 716, 728, 733, 734, and 735.

In some embodiments, the antisense oligonucleotide or contiguous nucleotide sequence comprises or consists of 10 to 30 nucleotides in length with at least 90% identity, preferably 100% identity, to SEQ ID NO: 287.

In some embodiments, the antisense oligonucleotide or contiguous nucleotide sequence comprises or consists of 10 to 30 nucleotides in length with at least 90% identity, preferably 100% identity, to SEQ ID NO: 342.

In some embodiments, the antisense oligonucleotide or contiguous nucleotide sequence comprises or consists of 10 to 30 nucleotides in length with at least 90% identity, preferably 100% identity, to SEQ ID NO: 640.

In some embodiments, the antisense oligonucleotide or contiguous nucleotide sequence comprises or consists of 10 to 30 nucleotides in length with at least 90% identity, preferably 100% identity, to SEQ ID NO: 466.

In some embodiments, the antisense oligonucleotide or contiguous nucleotide sequence comprises or consists of 10 to 30 nucleotides in length with at least 90% identity, preferably 100% identity, to SEQ ID NO: 566.

In embodiments where the oligonucleotide is longer than the contiguous nucleotide sequence (which is complementary to the target nucleic acid), the motif sequences in table 5 form the contiguous nucleotide sequence part of the antisense oligonucleotides of the invention. In some embodiments the sequence of the oligonucleotide is equivalent to the contiguous nucleotide sequence (e.g. if no biocleavable linkers are added).

It is understood that the contiguous nucleobase sequences (motif sequence) can be modified to for example increase nuclease resistance and/or binding affinity to the target nucleic acid.

Modifications are described in the definitions and in the “Oligonucleotide design” section. Table 5 lists preferred designs of each motif sequence.

Oligonucleotide Design

Oligonucleotide design refers to the pattern of nucleoside sugar modifications in the oligonucleotide sequence. The oligonucleotides of the invention comprise sugar-modified nucleosides and may also comprise DNA or RNA nucleosides. In some embodiments, the oligonucleotide comprises sugar-modified nucleosides and DNA nucleosides. Incorporation of modified nucleosides into the oligonucleotide of the invention may enhance the affinity of the oligonucleotide for the target nucleic acid. In that case, the modified nucleosides can be referred to as affinity enhancing modified nucleotides, the modified nucleosides may also be termed units.

In an embodiment, the oligonucleotide comprises at least 1 modified nucleoside, such as at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15 or at least 16 modified nucleosides. In an embodiment the oligonucleotide comprises from 1 to 10 modified nucleosides, such as from 2 to 8 modified nucleosides, such as from 3 to 7 modified nucleosides, such as from 4 to 6 modified nucleosides, such as 3, 4, 5, 6 or 7 modified nucleosides.

In an embodiment, the oligonucleotide comprises one or more sugar modified nucleosides, such as 2′ sugar modified nucleosides. Preferably the oligonucleotide of the invention comprise the one or more 2′ sugar modified nucleoside independently selected from the group consisting of 2′-O-alkyl-RNA, 2′-O-methyl-RNA, 2′-alkoxy-RNA, 2′-O-methoxyethyl-RNA, 2′-amino-DNA, 2′-fluoro-DNA, arabino nucleic acid (ANA), 2′-fluoro-ANA and LNA nucleosides. Even more preferably the one or more modified nucleoside is a locked nucleic acid (LNA).

In a further embodiment the oligonucleotide comprises at least one modified internucleoside linkage. In a preferred embodiment all the internucleoside linkages within the contiguous nucleotide sequence are phosphorothioate or boranophosphate internucleoside linkages. In some embodiments all the internucleotide linkages in the contiguous sequence of the oligonucleotide are phosphorothioate linkages.

In some embodiments, the oligonucleotide of the invention comprises at least one LNA nucleoside, such as 1, 2, 3, 4, 5, 6, 7, or 8 LNA nucleosides, such as from 2 to 6 LNA nucleosides, such as from 3 to 7 LNA nucleosides, 4 to 6 LNA nucleosides or 3, 4, 5, 6 or 7 LNA nucleosides. In some embodiments, at least 75% of the modified nucleosides in the oligonucleotide are LNA nucleosides, such as 80%, such as 85%, such as 90% of the modified nucleosides are LNA nucleosides. In a still further embodiment all the modified nucleosides in the oligonucleotide are LNA nucleosides. In a further embodiment, the oligonucleotide may comprise both beta-D-oxy-LNA, and one or more of the following LNA nucleosides: thio-LNA, amino-LNA, oxy-LNA, and/or ENA in either the beta-D or alpha-L configurations or combinations thereof. In a further embodiment, all LNA cytosine units are 5-methyl-cytosine. In a preferred embodiment the oligonucleotide or contiguous nucleotide sequence has at least 1 LNA nucleoside at the 5′ end and at least 2 LNA nucleosides at the 3′ end of the nucleotide sequence.

In some embodiments, the oligonucleotide of the invention comprises at least one modified nucleoside which is a 2′-MOE-RNA nucleoside, such as 2, 3, 4, 5, 6, 7, 8, 9 or 10 2′-MOE-RNA nucleosides. In some embodiments, at least one of said modified nucleoside is 2′-fluoro DNA, such as 2, 3, 4, 5, 6, 7, 8, 9 or 10 2′-fluoro-DNA nucleosides.

In some embodiments, the oligonucleotide of the invention comprises at least one LNA nucleoside and at least one 2′ substituted modified nucleoside.

In some embodiments of the invention, the oligonucleotide comprise both 2′ sugar modified nucleosides and DNA units. Preferably the oligonucleotide comprises both LNA and DNA nucleosides (units). Preferably, the combined total of LNA and DNA units is 8-30, such as 10-25, preferably 12-22, such as 12-18, even more preferably 11-16. In some embodiments of the invention, the nucleotide sequence of the oligonucleotide, such as the contiguous nucleotide sequence consists of at least one or two LNA nucleosides and the remaining nucleosides are DNA units. In some embodiments the oligonucleotide comprises only LNA nucleosides and naturally occurring nucleosides (such as RNA or DNA, most preferably DNA nucleosides), optionally with modified internucleoside linkages such as phosphorothioate.

In an embodiment of the invention the oligonucleotide of the invention is capable of recruiting RNase H.

The structural design of the oligonucleotide of the invention may be selected from gapmers, gapbreakers, headmers and tailmers.

Gapmer Design

In a preferred embodiment the oligonucleotide of the invention has a gapmer design or structure also referred herein merely as “Gapmer”. In a gapmer structure the oligonucleotide comprises at least three distinct structural regions a 5′-flank, a gap and a 3′-flank, F-G-F′ in ‘5→3’ orientation. In this design, flanking regions F and F′ (also termed wing regions) comprise a contiguous stretch of modified nucleosides, which are complementary to the PD-L1 target nucleic acid, while the gap region, G, comprises a contiguous stretch of nucleotides which are capable of recruiting a nuclease, preferably an endonuclease such as RNase, for example RNase H, when the oligonucleotide is in duplex with the target nucleic acid. Nucleosides which are capable of recruiting a nuclease, in particular RNase H, can be selected from the group consisting of DNA, alpha-L-oxy-LNA, 2′-Flouro-ANA and UNA. Regions F and F′, flanking the 5′ and 3′ ends of region G, preferably comprise non-nuclease recruiting nucleosides (nucleosides with a 3′ endo structure), more preferably one or more affinity enhancing modified nucleosides. In some embodiments, the 3′ flank comprises at least one LNA nucleoside, preferably at least 2 LNA nucleosides. In some embodiments, the 5′ flank comprises at least one LNA nucleoside. In some embodiments both the 5′ and 3′ flanking regions comprise a LNA nucleoside. In some embodiments all the nucleosides in the flanking regions are LNA nucleosides. In other embodiments, the flanking regions may comprise both LNA nucleosides and other nucleosides (mixed flanks), such as DNA nucleosides and/or non-LNA modified nucleosides, such as 2′ substituted nucleosides. In this case the gap is defined as a contiguous sequence of at least 5 RNase H recruiting nucleosides (nucleosides with a 2′ endo structure, preferably DNA) flanked at the 5′ and 3′ end by an affinity enhancing modified nucleoside, preferably LNA, such as beta-D-oxy-LNA. Consequently, the nucleosides of the 5′ flanking region and the 3′ flanking region which are adjacent to the gap region are modified nucleosides, preferably non-nuclease recruiting nucleosides.

Region F

Region F (5′ flank or 5′ wing) attached to the ′5 end of region G comprises, contains or consists of at least one modified nucleoside such as at least 2, at least 3, at least 4, at least 5, at least 6, at least 7 modified nucleosides. In an embodiment region F comprises or consists of from 1 to 7 modified nucleosides, such as from 2 to 6 modified nucleosides, such as from 2 to 5 modified nucleosides, such as from 2 to 4 modified nucleosides, such as from 1 to 3 modified nucleosides, such as 1, 2, 3 or 4 modified nucleosides. The F region is defined by having at least on modified nucleoside at the 5′ end and at the 3′ end of the region.

In some embodiments, the modified nucleosides in region F have a 3′ endo structure.

In an embodiment, one or more of the modified nucleosides in region F are 2′ modified nucleosides. In one embodiment all the nucleosides in Region F are 2′ modified nucleosides.

In another embodiment region F comprises DNA and/or RNA in addition to the 2′ modified nucleosides. Flanks comprising DNA and/or RNA are characterized by having a 2′ modified nucleoside in the 5′ end and the 3′ end (adjacent to the G region) of the F region. In one embodiment the region F comprise DNA nucleosides, such as from 1 to 3 contiguous DNA nucleosides, such as 1 to 3 or 1 to 2 contiguous DNA nucleosides. The DNA nucleosides in the flanks should preferably not be able to recruit RNase H. In some embodiments the 2′ modified nucleosides and DNA and/or RNA nucleosides in the F region alternate with 1 to 3 2′ modified nucleosides and 1 to 3 DNA and/or RNA nucleosides. Such flanks can also be termed alternating flanks. The length of the 5′ flank (region F) in oligonucleotides with alternating flanks may be 4 to 10 nucleosides, such as 4 to 8, such as 4 to 6 nucleosides, such as 4, 5, 6 or 7 modified nucleosides. In some embodiments only the 5′ flank of the oligonucleotide is alternating. Specific examples of region F with alternating nucleosides are

2′ 1-3 -N′ 1-4 -2′ 1-3

2′ 1-2 -N′ 1-2 -2′ 1-2 -N′ 1-2 -2′ 1-2

Where 2′ indicates a modified nucleoside and N′ is a RNA or DNA. In some embodiments all the modified nucleosides in the alternating flanks are LNA and the N′ is DNA. In a further embodiment one or more of the 2′ modified nucleosides in region F are selected from 2′-O-alkyl-RNA units, 2′-O-methyl-RNA, 2′-amino-DNA units, 2′-fluoro-DNA units, 2′-alkoxy-RNA, MOE units, LNA units, arabino nucleic acid (ANA) units and 2′-fluoro-ANA units.

In some embodiments the F region comprises both LNA and a 2′ substituted modified nucleoside. These are often termed mixed wing or mixed flank oligonucleotides.

In one embodiment of the invention all the modified nucleosides in region F are LNA nucleosides. In a further embodiment all the nucleosides in Region F are LNA nucleosides. In a further embodiment the LNA nucleosides in region F are independently selected from the group consisting of oxy-LNA, thio-LNA, amino-LNA, cET, and/or ENA, in either the beta-D or alpha-L configurations or combinations thereof. In a preferred embodiment region F comprise at least 1 beta-D-oxy LNA unit, at the 5′ end of the contiguous sequence.

Region G

Region G (gap region) preferably comprise, contain or consist of at least 4, such as at least 5, such as at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15 or at least 16 consecutive nucleosides capable of recruiting the aforementioned nuclease, in particular RNaseH. In a further embodiment region G comprise, contain or consist of from 5 to 12, or from 6 to 10 or from 7 to 9, such as 8 consecutive nucleotide units capable of recruiting aforementioned nuclease.

The nucleoside units in region G, which are capable of recruiting nuclease are in an embodiment selected from the group consisting of DNA, alpha-L-LNA, C4′ alkylated DNA (as described in PCT/EP2009/050349 and Vester et al., Bioorg. Med. Chem. Lett. 18 (2008) 2296-2300, both incorporated herein by reference), arabinose derived nucleosides like ANA and 2′F-ANA (Mangos et al. 2003 J. AM. CHEM. SOC. 125, 654-661), UNA (unlocked nucleic acid) (as described in Fluiter et al., Mol. Biosyst., 2009, 10, 1039 incorporated herein by reference). UNA is unlocked nucleic acid, typically where the bond between C2 and C3 of the ribose has been removed, forming an unlocked “sugar” residue.

In a still further embodiment at least one nucleoside unit in region G is a DNA nucleoside unit, such as from 1 to 18 DNA units, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17 DNA units, preferably from 2 to 17 DNA units, such as from 3 to 16 DNA units, such as from 4 to 15 DNA units. such as from 5 to 14 DNA units, such as from 6 to 13 DNA units, such as from 7 to 12 DNA units, such as from 8 to 11 DNA units, more preferably from units 8 to 17 DNA units, or from 9 to 16 DNA units, 10 to 15 DNA units or 11 to 13 DNA units, such as 8, 9, 10, 11, 12, 13, 14, 154, 16, 17 DNA units. In some embodiments, region G consists of 100% DNA units.

In further embodiments the region G may consist of a mixture of DNA and other nucleosides capable of mediating RNase H cleavage. Region G may consist of at least 50% DNA, more preferably 60%, 70% or 80% DNA, and even more preferred 90% or 95% DNA.

In a still further embodiment at least one nucleoside unit in region G is an alpha-L-LNA nucleoside unit, such as at least one alpha-L-LNA, such as 2, 3, 4, 5, 6, 7, 8 or 9 alpha-L-LNA.

In a further embodiment, region G comprises the least one alpha-L-LNA is alpha-L-oxy-LNA. In a further embodiment region G comprises a combination of DNA and alpha-L-LNA nucleoside units.

In some embodiments, nucleosides in region G have a 2′ endo structure.

In some embodiments region G may comprise a gapbreaker nucleoside, leading to a gapbreaker oligonucleotide, which is capable of recruiting RNase H.

Region F′

Region F′ (3′ flank or 3′ wing) attached to the ′3 end of region G comprises, contains or consists of at least one modified nucleoside such as at least 2, at least 3, at least 4, at least 5, at least 6, at least 7 modified nucleosides. In an embodiment region F′ comprise or consist of from 1 to 7 modified nucleosides, such as from 2 to 6 modified nucleoside, such as from 2 to 4 modified nucleosides, such as from 1 to 3 modified nucleosides, such as 1, 2, 3 or 4 modified nucleosides. The F′ region is defined by having at least on modified nucleoside at the 5′ end and at the 3′ end of the region.

In some embodiments, the modified nucleosides in region F′ have a 3′ endo structure.

In an embodiment, one or more of the modified nucleosides in region F′ are 2′ modified nucleosides. In one embodiment all the nucleosides in Region F′ are 2′ modified nucleosides.

In an embodiment, one or more of the modified nucleosides in region F′ are 2′ modified nucleosides.

In one embodiment all the nucleosides in Region F′ are 2′ modified nucleosides. In another embodiment region F′ comprises DNA or RNA in addition to the 2′ modified nucleosides. Flanks comprising DNA or RNA are characterized by having a 2′ modified nucleoside in the 5′ end (adjacent to the G region) and the 3′ end of the F′ region. In one embodiment the region F′ comprises DNA nucleosides, such as from 1 to 4 contiguous DNA nucleosides, such as 1 to 3 or 1 to 2 contiguous DNA nucleosides. The DNA nucleosides in the flanks should preferably not be able to recruit RNase H. In some embodiments the 2′ modified nucleosides and DNA and/or RNA nucleosides in the F′ region alternate with 1 to 3 2′ modified nucleosides and 1 to 3 DNA and/or RNA nucleosides, such flanks can also be termed alternating flanks. The length of the 3′ flank (region F′) in oligonucleotides with alternating flanks may be 4 to 10 nucleosides, such as 4 to 8, such as 4 to 6 nucleosides, such as 4, 5, 6 or 7 modified nucleosides. In some embodiments only the 3′ flank of the oligonucleotide is alternating. Specific examples of region F′ with alternating nucleosides are

2′ 1-2 -N′ 1-4 -2′ 1-4

2′ 1-2 -N′ 1-2 -2′ 1-2 -N′ 1-2 -2′ 1-2

Where 2′ indicates a modified nucleoside and N′ is a RNA or DNA. In some embodiments all the modified nucleosides in the alternating flanks are LNA and the N′ is DNA. In a further embodiment modified nucleosides in region F′ are selected from 2′-O-alkyl-RNA units, 2′-O-methyl-RNA, 2′-amino-DNA units, 2′-fluoro-DNA units, 2′-alkoxy-RNA, MOE units, LNA units, arabino nucleic acid (ANA) units and 2′-fluoro-ANA units.

In some embodiments the F′ region comprises both LNA and a 2′ substituted modified nucleoside. These are often termed mixed wing or mixed flank oligonucleotides.

In one embodiment of the invention all the modified nucleosides in region F′ are LNA nucleosides. In a further embodiment all the nucleosides in Region F′ are LNA nucleosides. In a further embodiment the LNA nucleosides in region F′ are independently selected from the group consisting of oxy-LNA, thio-LNA, amino-LNA, cET and/or ENA, in either the beta-D or alpha-L configurations or combinations thereof. In a preferred embodiment region F′ has at least 2 beta-D-oxy LNA unit, at the 3′ end of the contiguous sequence.

Region D′ and D″

Region D′ and D″ can be attached to the 5′ end of region F or the 3′ end of region F′, respectively. Region D′ or D″ are optional.

Region D′ or D″ may independently comprise 0 to 5, such as 1 to 5, such as 2 to 4, such as 0, 1, 2, 3, 4 or 5 additional nucleotides, which may be complementary or non-complementary to the target nucleic acid. In this respect the oligonucleotide of the invention, may in some embodiments comprise a contiguous nucleotide sequence capable of modulating the target which is flanked at the 5′ and/or 3′ end by additional nucleotides. Such additional nucleotides may serve as a nuclease susceptible biocleavable linker (see definition of linkers). In some embodiments the additional 5′ and/or 3′ end nucleosides are linked with phosphodiester linkages, and may be DNA or RNA. In another embodiment, the additional 5′ and/or 3′ end nucleosides are modified nucleosides which may for example be included to enhance nuclease stability or for ease of synthesis. In one embodiment, the oligonucleotide of the invention, comprises a region D′ and/or D″ at the 5′ or 3′ end of the contiguous nucleotide sequence. In a further embodiment the D′ and/or D″ region is composed of 1 to 5 phosphodiester linked DNA or RNA nucleosides which are not complementary to the target nucleic acid.

The gapmer oligonucleotide of the present invention can be represented by the following formulae:

5′-F-G-F′-3′; in particular F 1-7 -G 4-12 -F′ 1-7

5′-D′-F-G-F′-3′, in particular D′ 1-3 -F 1-7 -G 4-12 -F′ 1-7

5′-F-G-F′-D″-3′, in particular F 1-7 -G 4-12 -F′ 1-7 -D″ 1-3

5′-D′-F-G-F′-D′-3″, in particular D′ 1-3 -F 1-7 -G 4-12 -F′ 1-7 -D″ 1-3 The preferred number and types of nucleosides in regions F, G and F′, D′ and D″ have been described above. The oligonucleotide conjugates of the present invention have a region C covalently attached to either the 5′ or 3′ end of the oligonucleotide, in particular the gapmer oligonucleotides presented above.

In one embodiment the oligonucleotide conjugate of the invention comprises a oligonucleotide with the formula 5′-D′-F-G-F′-3′ or 5′-F-G-F′-D″-3′, where region F and F′ independently comprise 1-7 modified nucleosides, G is a region between 6 and 16 nucleosides which are capable of recruiting RNaseH and region D′ or D″ comprise 1-5 phosphodiester linked nucleosides. Preferably region D′ or D″ is present in the end of the oligonucleotide where conjugation to a conjugate moiety is contemplated.

Examples of oligonucleotides with alternating flanks can be represented by the following formulae:

2′ 1-3 -N′ 1-4 -2′ 1-3 -Ge 6-12 -2′ 1-2 -N′ 1-4 -2′ 1-4

2′ 1-2 -N′ 1-2 -2′ 1-2 -N′ 1-2 -2′ 1-2 -G 6-12 -2′ 1-2 -N′ 1-2 -2′ 1-2 -N′ 1-2 -2′ 1-2

F-G 6-12 -2′ 1-2 -N′ 1-4 -2′ 1-4

F-G 6-12 -2′ 1-2 -N′ 1-2 -2′ 1-2 -N′ 1-2 -2′ 1-2

2′ 1-3 -N′ 1-4 -2′ 1-3 -G 6-12 -F′

2′ 1-2 -N′ 1-2 -2′ 1-2 -N 1-2 -2′ 1-2 -Ge 6-12 -F′

Where a flank is indicated by F or F′ it only contains 2′ modified nucleosides, such as LNA nucleosides. The preferred number and types of nucleosides in the alternating regions, and region F, G and F′, D′ and D″ have been described above.

In some embodiments the oligonucleotide is a gapmer consisting of 16, 17, 18, 19, 20, 21, 22 nucleotides in length, wherein each of regions F and F′ independently consists of 1, 2, 3 or 4 modified nucleoside units complementary to the PD-L1 target nucleic acid and region G consists of 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 nucleoside units, capable of recruiting nuclease when in duplex with the PD-L1 target nucleic acid and region D′ consists of 2 phosphodiester linked DNAs.

In a further embodiments, the oligonucleotide is a gapmer wherein each of regions F and F′ independently consists of 3, 4, 5 or 6 modified nucleoside units, such as nucleoside units containing a 2′-O-methoxyethyl-ribose sugar (2′-MOE) or nucleoside units containing a 2′-fluoro-deoxyribose sugar and/or LNA units, and region G consists of 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17 nucleoside units, such as DNA units or other nuclease recruiting nucleosides such as alpha-L-LNA or a mixture of DNA and nuclease recruiting nucleosides.

In a further specific embodiment, the oligonucleotide is a gapmer wherein each of regions F and F′ region consists of two LNA units each, and region G consists of 12, 13, 14 nucleoside units, preferably DNA units. Specific gapmer designs of this nature include 2-12-2, 2-13-2 and 2-14-2.

In a further specific embodiment, the oligonucleotide is a gapmer wherein each of regions F and F′ independently consists of three LNA units, and region G consists of 8, 9, 10, 11, 12, 13 or 14 nucleoside units, preferably DNA units. Specific gapmer designs of this nature include 3-8-3, 3-9-3 3-10-3, 3-11-3, 3-12-3, 3-13-3 and 3-14-3.

In a further specific embodiment, the oligonucleotide is a gapmer wherein each of regions F and F′ consists of four LNA units each, and region G consists of 8 or 9, 10, 11 or 12 nucleoside units, preferably DNA units. Specific gapmer designs of this nature include 4-8-4, 4-9-4, 4-10-4, 4-11-4 and 4-12-4.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 6 nucleosides and independently 1 to 4 modified nucleosides in the wings including 1-6-1, 1-6-2, 2-6-1, 1-6-3, 3-6-1, 1-6-4, 4-6-1, 2-6-2, 2-6-3, 3-6-2 2-6-4, 4-6-2, 3-6-3, 3-6-4 and 4-6-3 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 7 nucleosides and independently 1 to 4 modified nucleosides in the wings including 1-7-1, 2-7-1, 1-7-2, 1-7-3, 3-7-1, 1-7-4, 4-7-1, 2-7-2, 2-7-3, 3-7-2, 2-7-4, 4-7-2, 3-7-3, 3-7-4, 4-7-3 and 4-7-4 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 8 nucleosides and independently 1 to 4 modified nucleosides in the wings including 1-8-1, 1-8-2, 1-8-3, 3-8-1, 1-8-4, 4-8-1, 2-8-1, 2-8-2, 2-8-3, 3-8-2, 2-8-4, 4-8-2, 3-8-3, 3-8-4, 4-8-3 and 4-8-4 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 9 nucleosides and independently 1 to 4 modified nucleosides in the wings including, 1-9-1, 2-9-1, 1-9-2, 1-9-3, 3-9-1, 1-9-4, 4-9-1, 2-9-2, 2-9-3, 3-9-2, 2-9-4, 4-9-2, 3-9-3, 3-9-4, 4-9-3 and 4-9-4 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 10 nucleosides including, 1-10-1, 2-10-1, 1-10-2, 1-10-3, 3-10-1, 1-10-4, 4-10-1, 2-10-2, 2-10-3, 3-10-2, 2-10-4, 4-10-2, 3-10-3, 3-10-4, 4-10-3 and 4-10-4 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 11 nucleosides including, 1-11-1, 2-11-1, 1-11-2, 1-11-3, 3-11-1, 1-11-4, 4-11-1, 2-11-2, 2-11-3, 3-11-2, 2-11-4, 4-11-2, 3-11-3, 3-11-4, 4-11-3 and 4-11-4 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 12 nucleosides including, 1-12-1, 2-12-1, 1-12-2, 1-12-3, 3-12-1, 1-12-4, 4-12-1, 2-12-2, 2-12-3, 3-12-2, 2-12-4, 4-12-2, 3-12-3, 3-12-4, 4-12-3 and 4-12-4 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 13 nucleosides including, 1-13-1, 2-13-1, 1-13-2, 1-13-3, 3-13-1, 1-13-4, 4-13-1, 2-13-2, 2-13-3, 3-13-2, 2-13-4, 4-13-2, 3-13-3, 3-13-4, 4-13-3 and 4-13-4 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 14 nucleosides including, 1-14-1, 2-14-1, 1-14-2, 1-14-3, 3-14-1, 1-14-4, 4-14-1, 2-14-2, 2-14-3, 3-14-2, 2-14-4, 4-14-2, 3-14-3, 3-14-4, 4-14-3 and 4-14-4 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 15 nucleosides including, 1-15-1, 2-15-1, 1-15-2, 1-15-3, 3-15-1, 1-15-4, 4-15-1, 2-15-2, 2-15-3, 3-15-2, 2-15-4, 4-15-2 and 3-15-3 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 16 nucleosides including, 1-16-1, 2-16-1, 1-16-2, 1-16-3, 3-16-1, 1-16-4, 4-16-1, 2-16-2, 2-16-3, 3-16-2, 2-16-4, 4-16-2 and 3-16-3 gapmers.

Specific gapmer designs of this nature include F-G-F′ designs selected from a group consisting of a gap with 17 nucleosides including, 1-17-1, 2-17-1, 1-17-2, 1-17-3, 3-17-1, 1-17-4, 4-17-1, 2-17-2, 2-17-3 and 3-17-2 gapmers.

In all instances the F-G-F′ design may further include region D′ and/or D″, which may have 1, 2 or 3 nucleoside units, such as DNA units, such as 2 phosphodiester linked DNA units.

Preferably, the nucleosides in region F and F′ are modified nucleosides, while nucleotides in region G are preferably unmodified nucleosides.

In each design, the preferred modified nucleoside is LNA.

In another embodiment all the internucleoside linkages in the gap in a gapmer are phosphorothioate and/or boranophosphate linkages. In another embodiment all the internucleoside linkages in the flanks (F and F′ region) in a gapmer are phosphorothioate and/or boranophosphate linkages. In another preferred embodiment all the internucleoside linkages in the D′ and D″ region in a gapmer are phosphodiester linkages.

For specific gapmers as disclosed herein, when the cytosine (C) residues are annotated as 5-methyl-cytosine, in various embodiments, one or more of the Cs present in the oligonucleotide may be unmodified C residues.

In a particular embodiment, the gapmer is a so-called shortmer as described in WO2008/113832 incorporated herein by reference.

Further gapmer designs are disclosed in WO2004/046160, WO2007/146511 and incorporated by reference.

For certain embodiments of the invention, the oligonucleotide is selected from the group of oligonucleotide compounds with CMP-ID-NO: 5_1 to 743_1 and 771_1.

For certain embodiments of the invention, the oligonucleotide is selected from the group of oligonucleotide compounds with CMP-ID-NO 6_1, 8_1, 9_1, 13_1, 41_1, 42_1, 58_1, 77_1, 92_1, 111_1, 128_1, 151_1, 164_1, 166_1, 169_1, 171_1, 222_1, 233_1, 245_1, 246_1, 250_1, 251_1, 252_1, 256_1, 272_1, 273_1, 287_1, 292_1, 303_1, 314_1, 318_1, 320_1, 324_1, 336_1, 342_1, 343_1, 344_1, 345_1, 346_1, 349_1, 359_1, 360_1, 374_1, 408_1, 409_1, 415_1, 417_1, 424_1, 429_1, 430_1, 458_1, 464_1, 466_1, 474_1, 490_1, 493_1, 512_1, 519_1, 519_1, 529_1, 533_1, 534_1, 547_1, 566_1, 567_1, 578_1, 582_1, 601_1, 619_1, 620_1, 636_1, 637_1, 638_1, 640_1, 645_1, 650_1, 651_1, 652_1, 653_1, 658_1, 659_1, 660_1, 665_1, 678_1, 679_1, 680_1, 682_1, 683_1, 684_1, 687_1, 694_1, 706_1, 716_1, 728_1, 733_1, 734_1, and 735_1.

In one preferred embodiment of the invention, the oligonucleotide is CMP-ID-NO: 287_1.

In another preferred embodiment of the invention, the oligonucleotide is CMP-ID-NO: 342_1.

In another preferred embodiment of the invention, the oligonucleotide is CMP-ID-NO: 640_1.

In another preferred embodiment of the invention, the oligonucleotide is CMP-ID-NO: 466_1.

In another preferred embodiment of the invention, the oligonucleotide is CMP-ID-NO: 566_1.

In a further embodiment of the invention the contiguous nucleotide sequence of the oligonucleotide motifs and oligonucleotide compounds of the invention comprise two to four additional phosphodiester linked nucleosides at the 5′ end of the contiguous nucleotide sequence (e.g. region D′). In one embodiment the nucleosides serve as a biocleavable linker (see section on biocleavable linkers). In a preferred embodiment a ca (cytidine-adenosine) dinucleotide is linked to the 5′ end of contiguous nucleotide sequence (i.e. any one of the motif sequences or oligonucleotide compounds listed in table 5) via a phosphodiester linkage. In a preferred embodiment the ca di nucleotide is not complementary to the target sequence at the position where the reminder of the contiguous nucleotide is complementary.

In some embodiments of the invention the oligonucleotide or contiguous nucleotide sequence is selected from the group consisting of the nucleotide motif sequences with SEQ ID NO: 766, 767, 768, 769 and 770.

In some embodiments of the invention the oligonucleotide is selected from the group consisting of the oligonucleotide compounds with CMP-ID-NO 766_1, 767_1, 768_1, 769_1 and 770_1.

Carbohydrate Conjugate Moieties

Carbohydrate conjugate moieties include but are not limited to galactose, lactose, n-acetylgalactosamine, mannose and mannose-6-phosphate. Carbohydrate conjugates may be used to enhance delivery or activity in a range of tissues, such as liver and/or muscle. See, for example, EP1495769, WO99/65925, Yang et al., Bioconjug Chem (2009) 20(2): 213-21. Zatsepin & Oretskaya Chem Biodivers. (2004) 1(10): 1401-17.

In some embodiments the carbohydrate conjugate moiety is multivalent, such as, for example 2, 3 or 4 identical or non-identical carbohydrate moieties may be covalently joined to the oligonucleotide, optionally via a linker or linkers. In some embodiments the invention provides a conjugate comprising the oligonucleotide of the invention and a carbohydrate conjugate moiety.

In some embodiments, the conjugate moiety is or may comprise mannose or mannose-6-phosphate. This is particular useful for targeting muscle cells, see for example US 2012/122801.

Conjugate moieties capable of binding to the asialoglycoprotein receptor (ASGPr) are particular useful for targeting hepatocytes in liver. In some embodiments the invention provides a oligonucleotide conjugate comprising the oligonucleotide of the invention and an asialoglycoprotein receptor targeting conjugate moiety. The asialoglycoprotein receptor targeting conjugate moiety comprises one or more carbohydrate moieties capable of binding to the asialoglycoprotein receptor (ASPGr binding carbohydrate moieties) with affinity equal to or greater than that of galactose. The affinities of numerous galactose derivatives for the asialoglycoprotein receptor have been studied (see for example: Jobst, S. T. and Drickamer, K. JB. C. 1996, 271, 6686) or are readily determined using methods typical in the art.

One aspect of the present invention is an antisense oligonucleotide conjugate comprising a) an oligonucleotide (Region A) comprising a contiguous nucleotide sequence of 10 to 30 nucleotides in length with at least 90% complementarity to a PD-L1 target nucleic acid; and b) at least one asialoglycoprotein receptor targeting conjugate moiety (Region C) covalently attached to the oligonucleotide in a). The oligonucleotide or a contiguous nucleotide sequence can be as described in any of the sections “oligonucleotides of the invention”, “oligonucleotide design and “gapmer design”.

In some embodiments asialoglycoprotein receptor targeting conjugate moiety comprises at least one ASPGr binding carbohydrate moiety selected from the group consisting of galactose, galactosamine, N-formyl-galactosamine, N-acetylgalactosamine, N-propionyl-galactosamine, N-n-butanoyl-galactosamine and N-isobutanoylgalactosamine. In some embodiments, the asialoglycoprotein receptor targeting conjugate moiety is mono-valent, di-valent, tri-valent or tetra-valent (i.e. containing 1, 2, 3 or 4 terminal carbohydrate moieties capable of binding to the asialoglycoprotein receptor). Preferably, the asialoglycoprotein receptor targeting conjugate moiety is di-valent, even more preferred it is trivalent. In a preferred embodiment the asialoglycoprotein receptor targeting conjugate moiety comprises 1 to 3 N-acetylgalactosamine (GalNAc) moieties (also termed a GalNAc conjugate). In some embodiments the oligonucleotide conjugate comprises a asialoglycoprotein receptor targeting conjugate moiety that is a tri-valent N-acetylgalactosamine (GalNAc) moiety. GalNAc conjugates have been used with phosphodiester, methylphosphonate and PNA antisense oligonucleotides (e.g. U.S. Pat. No. 5,994,517 and Hangeland et al., Bioconjug Chem. 1995 November-December; 6(6):695-701, Biessen et al 1999 Biochem J. 340, 783-792 and Maier et al 2003 Bioconjug Chem 14, 18-29) and siRNAs (e.g. WO 2009/126933, WO 2012/089352 & WO 2012/083046) and with LNA and 2′-MOE modified nucleosides WO 2014/076196 WO 2014/207232 and WO 2014/179620 (hereby incorporated by reference).

To generate the asialoglycoprotein receptor targeting conjugate moiety the ASPGr binding carbohydrate moieties (preferably GalNAc) are attached to a brancher molecule through the C-I carbons of the saccharides. The ASPGr binding carbohydrate moieties are preferably linked to the brancher molecule via spacers. A preferred spacer is a flexible hydrophilic spacer (U.S. Pat. No. 5,885,968; Biessen et al. J. Med. Chern. 1995 Vol. 39 p. 1538-1546). A preferred flexible hydrophilic spacer is a PEG spacer. A preferred PEG spacer is a PEG3 spacer (three ethylene units). The brancher molecule can be any small molecule which permits attachment of two or three terminal ASPGr binding carbohydrate moieties and further permits attachment of the branch point to the oligonucleotide. An exemplary brancher molecule is a di-lysine. A di-lysine molecule contains three amine groups through which three ASPGr binding carbohydrate moieties may be attached and a carboxyl reactive group through which the di-lysine may be attached to the oligonucleotide. Alternative brancher molecules may be a doubler or trebler such as those supplied by Glen Research. In some embodiments the brancher may be selected from the from the group consisting of 1,3-bis-[5-(4,4′-dimethoxytrityloxy)pentylamido]propyl-2-[(2-cyanoethyl)-(N,N-diisopropyl)] phosphoramidite (Glen Research Catalogue Number: 10-1920-xx), tris-2,2,2-[3-(4,4′-dimethoxytrityloxy)propyloxymethyl]ethyl-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite (Glen Research Catalogue Number: 10-1922-xx), tris-2,2,2-[3-(4,4′-dimethoxytrityloxy)propyloxymethyl]methyleneoxypropyl-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite and 1-[5-(4,4′-dimethoxy-trityloxy)pentylamido]-3-[5-fluorenomethoxy-carbonyl-oxy-pentylamido]-propyl-2-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite (Glen Research Catalogue Number: 10-1925-xx). WO 2014/179620 and PCT application No. PCT/EP2015/073331 describes the generation of various GalNAc conjugate moieties (hereby incorporated by reference). One or more linkers may be inserted between the brancher molecule and the oligonucleotide. In a preferred embodiment the linker is a biocleavable linker. The linker may be selected from the linkers described in the section “Linkers” and its subsections.

The asialoglycoprotein receptor targeting conjugate moiety, in particular the GalNAc conjugate moiety, may be attached to the 3′- or 5′-end of the oligonucleotide using methods known in the art. In preferred embodiments the asialoglycoprotein receptor targeting conjugate moiety is linked to the 5′-end of the oligonucleotide.

Pharmacokinetic modulators in relation to siRNAs delivery has been described in WO 2012/083046 (hereby incorporated by reference). In some embodiments the carbohydrate conjugate moiety comprises a pharmacokinetic modulator selected from the group consisting of a hydrophobic group having 16 or more carbon atoms, hydrophobic group having 16-20 carbon atoms, palmitoyl, hexadec-8-enoyl, oleyl, (9E,12E)-octadeca-9,12dienoyl, dioctanoyl, and C16-C20 acyl, and cholesterol. In a preferred embodiment the pharmacokinetic modulator containing carbohydrate conjugate moiety is a GalNAc conjugate.

Preferred carbohydrate conjugate moieties comprises one to three terminal ASPGr binding carbohydrate moieties, preferably N-acetylgalactosamine moiety(s). In some embodiments the carbohydrate conjugate moiety comprises three ASPGr binding carbohydrate moieties, preferably N-acetylgalactosamine moieties, linked via a spacer to a brancher molecule. The spacer molecule can be between 8 and 30 atoms long. A preferred carbohydrate conjugate moiety comprises three terminal GalNAc moieties linked via a PEG spacer to a di-lysine brancher molecule. Preferably the PEG spacer is a 3PEG spacer. Suitable asialoglycoprotein receptor targeting conjugate moieties are shown in FIG. 1 . A preferred asialoglycoprotein receptor targeting conjugate moiety is shown in FIG. 3 .

Other GalNAc conjugate moieties can include, for example, small peptides with GalNAc moieties attached such as Tyr-Glu-Glu-(aminohexyl GalNAc)3 (YEE(ahGalNAc)3; a glycotripeptide that binds to asialoglycoprotein receptor on hepatocytes, see, e.g., Duff, et al., Methods Enzymol, 2000, 313, 297); lysine-based galactose clusters (e.g., L3G4; Biessen, et al., Cardovasc. Med., 1999, 214); and cholane-based galactose clusters (e.g., carbohydrate recognition motif for asialoglycoprotein receptor).

In some embodiments of the invention the antisense oligonucleotide conjugate is selected from the group consisting of the following CPM ID NO: 766_2, 767_2, 768_2, 769_2 and 770_2.

In a preferred embodiment the antisense oligonucleotide conjugate corresponds to the compound represented in FIG. 4 .

In another preferred embodiment the antisense oligonucleotide conjugate corresponds to the compound represented in FIG. 5 .

In another preferred embodiment the antisense oligonucleotide conjugate corresponds to the compound represented in FIG. 6 .

In another preferred embodiment the antisense oligonucleotide conjugate corresponds to the compound represented in FIG. 7 .

In another preferred embodiment the antisense oligonucleotide conjugate corresponds to the compound represented in FIG. 8 .

Linkers

Biocleavable Linkers (Region B)

The use of a conjugate is often associated with enhanced pharmacokinetic or pharmeodynamic dynamic properties. However, the presence of a conjugate moiety may interfere with the activity of the oligonucleotide against its intended target, for example via steric hindrance preventing hybridization or nuclease recruitment (e.g. RNAseH). The use of a physiologically labile bond (biocleavable linker) between the oligonucleotide (region A or first region) and the conjugate moiety (region C or third region), allows for the improved properties due to the presence of the conjugate moiety, whilst ensuring that once at the target tissue, the conjugate group does not prevent effective activity of the oligonucleotide.

Cleavage of the physiologically labile bond occurs spontaneously when a molecule containing the labile bond reaches an appropriate intra- and/or extra-cellular environment. For example, a pH labile bond may be cleaved when the molecule enters an acidified endosome. Thus, a pH labile bond may be considered to be an endosomal cleavable bond. Enzyme cleavable bonds may be cleaved when exposed to enzymes such as those present in an endosome or lysosome or in the cytoplasm. A disulfide bond may be cleaved when the molecule enters the more reducing environment of the cell cytoplasm. Thus, a disulfide may be considered to be a cytoplasmic cleavable bond. As used herein, a pH-labile bond is a labile bond that is selectively broken under acidic conditions (pH<7). Such bonds may also be termed endosomally labile bonds, since cell endosomes and lysosomes have a pH less than 7.

For biocleavable linkers associated with a conjugate moiety for targeted delivery it is preferred that, the cleavage rate seen in the target tissue (for example muscle, liver, kidney or a tumor) is greater than that found in blood serum. Suitable methods for determining the level (%) of cleavage in target tissue versus serum or cleavage by S1 nuclease are described in the “Materials and methods” section. In some embodiments, the biocleavable linker (also referred to as the physiologically labile linker, or nuclease susceptible linker or region B), in a conjugate of the invention, is at least about 20% cleaved, such as at least about 30% cleaved, such as at least about 40% cleaved, such as at least about 50% cleaved, such as at least about 60% cleaved, such as at least about 70% cleaved, such as at least about 75% cleaved when compared against a standard.

In some embodiments, the oligonucleotide conjugate of the invention comprises three regions: i) a first region (region A), which comprises 10-25 contiguous nucleotides complementary to the target nucleic acid; ii) a second region (region B) which comprises a biocleavable linker and iii) a third region (region C) which comprises a conjugate moiety, such as an asialoglycoprotein receptor targeting conjugate moiety, wherein the third region is covalent linked to the second region which is covalently linked to the first region.

In one embodiment of the present invention the oligonucleotide conjugate comprises a biocleavable linker (Region B) between the contiguous nucleotide sequence (region A) and the asialoglycoprotein receptor targeting conjugate moiety (region C).

In some embodiments, the biocleavable linker may be situated either at the 5′ end and/or the 3′-end of the contiguous nucleotides complementary to the target nucleic acid (region A). In a preferred embodiment the biocleavable linker is at the 5′-end.

In some embodiments, the cleavable linker is susceptible to nuclease(s) which may for example, be expressed in the target cell. In some embodiments the biocleavable linker is composed of 2 to 5 consecutive phosphodiester linkages. The linker may be a short region (e.g. 1-10 as detailed in the definition of linkers) phosphodiester linked nucleosides. In some embodiments, the nucleosides in the biocleavable linker region B is (optionally independently) selected from the group consisting of DNA and RNA or modifications thereof which do not interfere with nuclease cleavage. Modifications of DNA and RNA nucleosides which do not interfere with nuclease cleavage may be non-naturally occurring nucleobases. Certain sugar-modified nucleosides may also allow nuclease cleavage such as an alpha-L-oxy-LNA. In some embodiments, all the nucleosides of region B comprise (optionally independently) either a 2′-OH ribose sugar (RNA) or a 2′-H sugar—i.e. RNA or DNA. In a preferred embodiment, at least two consecutive nucleosides of region B are DNA or RNA nucleosides (such as at least 3 or 4 or 5 consecutive DNA or RNA nucleosides). In an even more preferred embodiment, the nucleosides of region B are DNA nucleosides Preferably region B consists of between 1 to 5, or 1 to 4, such as 2, 3, 4 consecutive phosphodiester linked DNA nucleosides. In preferred embodiments region B is so short that it does not recruit RNAseH. In some embodiments, region B comprises no more than 3 or no more than 4 consecutive phospodiester linked DNA and/or RNA nucleosides (such as DNA nucleosides).

Where region B is composed of phosphodiester linked nucleosides, region A and B may together form the oligonucleotide that is linked to region C. In this context region A can be differentiated from region B in that Region A starts with at least one, preferably at least two, modified nucleosides with increased binding affinity to the target nucleic acid (e.g. LNA or nucleosides with a 2′ substituted sugar moiety) and region A on its own is capable of modulation of the expression the target nucleic acid in a relevant cell line. Furthermore, if region A comprises DNA or RNA nucleosides these are linked with nuclease resistant internucleoside linkage, such phosphorothioate or boranophosphate. Region B on the other hand comprises phophodiester linkages between DNA or RNA nucleosides. In some embodiments region B is not complementary to or comprises at least 50% mismatches to the target nucleic acid.

In some embodiments, region B is not complementary to the target nucleic acid sequence or to the contiguous nucleotides complementary to the target nucleic acid in region A.

In some embodiments, region B is complementary with the target nucleic acid sequence. In this respect region A and B together may form a single contiguous sequence which is complementary to the target sequence.

In some aspects of the invention the internucleoside linkage between the first (region A) and the second region (region B) may be considered part of the second region.

In some embodiments, the sequence of bases in region B is selected to provide an optimal endonuclease cleavage site, based upon the predominant endonuclease cleavage enzymes present in the target tissue or cell or sub-cellular compartment. In this respect, by isolating cell extracts from target tissues and non-target tissues, endonuclease cleavage sequences for use in region B may be selected based upon a preferential cleavage activity in the desired target cell (e.g. liver/hepatocytes) as compared to a non-target cell (e.g. kidney). In this respect, the potency of the compound for target down-regulation may be optimized for the desired tissue/cell.

In some embodiments region B comprises a dinucleotide of sequence AA, AT, AC, AG, TA, TT, TC, TG, CA, CT, CC, CG, GA, GT, GC, or GG, wherein C may be 5-methylcytosine, and/or T may be replaced with U. Preferably, the internucleoside linkage is a phosphodiester linkage. In some embodiments region B comprises a trinucleotide of sequence AAA, AAT, AAC, AAG, ATA, ATT, ATC, ATG, ACA, ACT, ACC, ACG, AGA, AGT, AGC, AGG, TAA, TAT, TAC, TAG, TTA, TTT, TTC, TAG, TCA, TCT, TCC, TCG, TGA, TGT, TGC, TGG, CAA, CAT, CAC, CAG, CTA, CTG, CTC, CTT, CCA, CCT, CCC, CCG, CGA, CGT, CGC, CGG, GAA, GAT, GAC, CAG, GTA, GTT, GTC, GTG, GCA, GCT, GCC, GCG, GGA, GGT, GGC, and GGG wherein C may be 5-methylcytosine and/or T may be replaced with U. Preferably, the internucleoside linkages are phosphodiester linkages. In some embodiments region B comprises a trinucleotide of sequence AAAX, AATX, AACX, AAGX, ATAX, ATTX, ATCX, ATGX, ACAX, ACTX, ACCX, ACGX, AGAX, AGTX, AGCX, AGGX, TAAX, TATX, TACX, TAGX, TTAX, TTTX, TTCX, TAGX, TCAX, TCTX, TCCX, TCGX, TGAX, TGTX, TGCX, TGGX, CAAX, CATX, CACX, CAGX, CTAX, CTGX, CTCX, CTTX, CCAX, CCTX, CCCX, CCGX, CGAX, CGTX, CGCX, CGGX, GAAX, GATX, GACX, CAGX, GTAX, GTTX, GTCX, GTGX, GCAX, GCTX, GCCX, GCGX, GGAX, GGTX, GGCX, and GGGX, wherein X may be selected from the group consisting of A, T, U, G, C and analogues thereof, wherein C may be 5-methylcytosine and/or T may be replaced with U. Preferably, the internucleoside linkages are phosphodiester linkages. It will be recognized that when referring to (naturally occurring) nucleobases A, T, U, G, C, these may be substituted with nucleobase analogues which function as the equivalent natural nucleobase (e.g. base pair with the complementary nucleoside).

Other Linkers (Region Y)

The linker can have at least two functionalities, one for attaching to the oligonucleotide and the other for attaching to the conjugate moiety. Example linker functionalities can be electrophilic for reacting with nucleophilic groups on the oligonucleotide or conjugate moiety, or nucleophilic for reacting with electrophilic groups. In some embodiments, linker functionalities include amino, hydroxyl, carboxylic acid, thiol, phosphoramidate, phosphorothioate, phosphate, phosphite, unsaturations (e.g., double or triple bonds), and the like. Some example linkers (region Y) include 8-amino-3,6-dioxaoctanoic acid (ADO), succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC), 6-aminohexanoic acid (AHEX or AHA), 6-aminohexyloxy, 4-aminobutyric acid, 4-aminocyclohexylcarboxylic acid, succinimidyl 4-(N-maleimidomethyl)cyclohexane-I-carboxy-(6-amido-caproate) (LCSMCC), succinimidyl m-maleimido-benzoylate (MBS), succinimidyl N-e-maleimido-caproylate (EMCS), succinimidyl 6-(beta-maleimido-propionamido) hexanoate (SMPH), succinimidyl N-(a-maleimido acetate) (AMAS), succinimidyl 4-(p-maleimidophenyl)butyrate (SMPB), beta-alanine (beta-ALA), phenylglycine (PHG), 4-aminocyclohexanoic acid (ACHC), beta-(cyclopropyl) alanine (beta-CYPR), amino dodecanoic acid (ADC), alylene diols, polyethylene glycols, amino acids, and the like. In some embodiments the linker (region Y) is an amino alkyl, such as a C2-C36 amino alkyl group, including, for example C6 to C12 amino alkyl groups. In a preferred embodiment the linker (region Y) is a C6 amino alkyl group. The amino alkyl group may be added to the oligonucleotide (region A or region A-B) as part of standard oligonucleotide synthesis, for example using a (e.g. protected) amino alkyl phosphoramidite. The linkage group between the amino alkyl and the oligonucleotide may for example be a phosphorothioate or a phosphodiester, or one of the other nucleoside linkage groups referred to herein. The amino alkyl group is covalently linked to the 5′ or 3′-end of the oligonucleotide. Commercially available amino alkyl linkers are for example 3′-Amino-Modifier reagent for linkage at the 3′-end of the oligonucleotide and for linkage at the 5′-end of an oligonucleotide 5′-Amino-Modifier C6 is available. These reagents are available from Glen Research Corporation (Sterling, Va.). These compounds or similar ones were utilized by Krieg, et al, Antisense Research and Development 1991, 1, 161 to link fluorescein to the 5′-terminus of an oligonucleotide. A wide variety of further linker groups are known in the art and can be useful in the attachment of conjugate moieties to oligonucleotides. A review of many of the useful linker groups can be found in, for example, Antisense Research and Applications, S. T. Crooke and B. Lebleu, Eds., CRC Press, Boca Raton, Fla., 1993, p. 303-350. Other compounds such as acridine have been attached to the 3′-terminal phosphate group of an oligonucleotide via a polymethylene linkage (Asseline, et al., Proc. Natl. Acad. Sci. USA 1984, 81, 3297). Any of the above groups can be used as a single linker (region Y) or in combination with one or more further linkers (region Y-Y′ or region Y-B or B-Y).

Linkers and their use in preparation of conjugates of oligonucleotides are provided throughout the art such as in WO 96/11205 and WO 98/52614 and U.S. Pat. Nos. 4,948,882; 5,525,465; 5,541,313; 5,545,730; 5,552,538; 5,580,731; 5,486,603; 5,608,046; 4,587,044; 4,667,025; 5,254,469; 5,245,022; 5,112,963; 5,391,723; 5,510,475; 5,512,667; 5,574,142; 5,684,142; 5,770,716; 6,096,875; 6,335,432; and 6,335,437, WO 2012/083046 each of which is incorporated by reference in its entirety.

Method of Manufacture

In a further aspect, the invention provides methods for manufacturing the oligonucleotides of the invention comprising reacting nucleotide units and thereby forming covalently linked contiguous nucleotide units comprised in the oligonucleotide. Preferably, the method uses phophoramidite chemistry (see for example Caruthers et al, 1987, Methods in Enzymology vol. 154, pages 287-313). In a further embodiment the method further comprises reacting the contiguous nucleotide sequence with a conjugating moiety (ligand). In a further aspect a method is provided for manufacturing the composition of the invention, comprising mixing the oligonucleotide or conjugated oligonucleotide of the invention with a pharmaceutically acceptable diluent, solvent, carrier, salt and/or adjuvant.

Pharmaceutical Composition

In a further aspect, the invention provides pharmaceutical compositions comprising any of the aforementioned oligonucleotides and/or oligonucleotide conjugates and a pharmaceutically acceptable diluent, solvent, carrier, salt and/or adjuvant. A pharmaceutically acceptable diluent includes phosphate-buffered saline (PBS) and pharmaceutically acceptable salts include, but are not limited to, sodium and potassium salts. In some embodiments the pharmaceutically acceptable diluent is sterile phosphate buffered saline. In some embodiments the oligonucleotide is used in the pharmaceutically acceptable diluent at a concentration of 50-300 μM solution.

Suitable formulations for use in the present invention are found in Remington's Pharmaceutical Sciences, Mack Publishing Company, Philadelphia, Pa., 17th ed., 1985. For a brief review of methods for drug delivery, see, e.g., Langer (Science 249:1527-1533, 1990). WO 2007/031091 provides further suitable and preferred examples of pharmaceutically acceptable diluents, carriers and adjuvants (hereby incorporated by reference). Suitable dosages, formulations, administration routes, compositions, dosage forms, combinations with other therapeutic agents, pro-drug formulations are also provided in WO2007/031091.

Oligonucleotides or oligonucleotide conjugates of the invention may be mixed with pharmaceutically acceptable active or inert substances for the preparation of pharmaceutical compositions or formulations. Compositions and methods for the formulation of pharmaceutical compositions are dependent upon a number of criteria, including, but not limited to, route of administration, extent of disease, or dose to be administered.

These compositions may be sterilized by conventional sterilization techniques, or may be sterile filtered. The resulting aqueous solutions may be packaged for use as is, or lyophilized, the lyophilized preparation being combined with a sterile aqueous carrier prior to administration. The pH of the preparations typically will be between 3 and 11, more preferably between 5 and 9 or between 6 and 8, and most preferably between 7 and 8, such as 7 to 7.5. The resulting compositions in solid form may be packaged in multiple single dose units, each containing a fixed amount of the above-mentioned agent or agents, such as in a sealed package of tablets or capsules. The composition in solid form can also be packaged in a container for a flexible quantity, such as in a squeezable tube designed for a topically applicable cream or ointment.

In some embodiments, the oligonucleotide or oligonucleotide conjugate of the invention is a prodrug. In particular with respect to oligonucleotide conjugates the conjugate moiety is cleaved of the oligonucleotide once the prodrug is delivered to the site of action, e.g. the target cell.

Applications

The oligonucleotides or oligonucleotide conjugates of the present invention may be utilized as research reagents for, for example, diagnostics, therapeutics and prophylaxis.

In research, such oligonucleotides or oligonucleotide conjugates may be used to specifically modulate the synthesis of PD-L1 protein in cells (e.g. in vitro cell cultures) and experimental animals thereby facilitating functional analysis of the target or an appraisal of its usefulness as a target for therapeutic intervention. Typically the target modulation is achieved by degrading or inhibiting the mRNA producing the protein, thereby prevent protein formation or by degrading or inhibiting a modulator of the gene or mRNA producing the protein.

If employing the oligonucleotide of the invention in research or diagnostics the target nucleic acid may be a cDNA or a synthetic nucleic acid derived from DNA or RNA.

The present invention provides an in vivo or in vitro method for modulating PD-L1 expression in a target cell which is expressing PD-L1, said method comprising administering an oligonucleotide or oligonucleotide conjugate of the invention in an effective amount to said cell.

In some embodiments, the target cell, is a mammalian cell in particular a human cell. The target cell may be an in vitro cell culture or an in vivo cell forming part of a tissue in a mammal. In preferred embodiments the target cell is present in the liver. Liver target cell can be selected from parenchymal cells (e.g. hepatocytes) and non-parenchymal cells such as Kupffer cells, LSECs, stellate cells (or Ito cells), cholangiocytes and liver-associated leukocytes (including T cells and NK cells). In some embodiments the target cell is an antigen-presenting cell. Antigen-presenting cells displays foreign antigens complexed with major histocompatibility complex (MHC) class I or class II on their surfaces. In some embodiments the antigen-presenting cell expresses MHC class II (i.e. professional antigen-presenting cells such as dendritic cells, macrophages and B cells).

In diagnostics the oligonucleotides may be used to detect and quantitate PD-L1 expression in cell and tissues by northern blotting, in-situ hybridisation or similar techniques.

For therapeutics oligonucleotides or oligonucleotide conjugates of the present invention or pharmaceutical compositions thereof may be administered to an animal or a human, suspected of having a disease or disorder, which can be alleviated or treated by reduction of the expression of PD-L1, in particular by reduction of the expression of PD-L1 in liver target cells.

The invention provides methods for treating or preventing a disease, comprising administering a therapeutically or prophylactically effective amount of an oligonucleotide, an oligonucleotide conjugate or a pharmaceutical composition of the invention to a subject suffering from or susceptible to the disease.

The invention also relates to an oligonucleotide, oligonucleotide conjugate or a pharmaceutical composition according to the invention for use as a medicament.

The oligonucleotide, oligonucleotide conjugate or a pharmaceutical composition according to the invention is typically administered in an effective amount.

The invention also provides for the use of the oligonucleotide or oligonucleotide conjugate or pharmaceutical composition of the invention as described for the manufacture of a medicament for the treatment of a disease or disorder as referred to herein. In one embodiment the disease is selected from a) viral liver infections such as HBV, HCV and HDV; b) parasite infections such as malaria, toxoplasmosis, leishmaniasis and trypanosomiasis and c) liver cancer or metastases in the liver.

In one embodiment, the invention relates to oligonucleotides, oligonucleotide conjugates or pharmaceutical compositions for use in the treatment of diseases or disorders selected from viral or parasitic infections. In a further embodiment the disease is selected from a) viral liver infections such as HBV, HCV and HDV; b) parasite infections such as malaria, toxoplasmosis, leishmaniasis and trypanosomiasis and c) liver cancer or metastases in the liver.

The disease or disorder, as referred to herein, is associated with immune exhaustion. In particular the disease or disorder is associated with exhaustion of virus-specific T-cell responses. In some embodiments disease or disorder may be alleviated or treated by reduction of PD-L1 expression.

The methods of the invention are preferably employed for treatment or prophylaxis against diseases associated with immune exhaustion.

In one embodiment of the invention the oligonucleotide, oligonucleotide conjugate or pharmaceutical compositions of the invention are used in restoration of immune response against a liver cancer or metastases in the liver.

In one embodiment of the invention the oligonucleotide, oligonucleotide conjugate or pharmaceutical compositions of the invention are used in restoration of immune response against a pathogen. In some embodiments the pathogen can be found in the liver. The pathogens can be a virus or a parasite, in particular those described herein. In a preferred embodiment the pathogen is HBV.

The invention further relates to use of an oligonucleotide, oligonucleotide conjugate or a pharmaceutical composition as defined herein for the manufacture of a medicament for the restoration of immunity against a viral or parasite infection as mentioned herein.

Oligonucleotides or oligonucleotide conjugates or pharmaceutical compositions of the present invention can be used in the treatment of viral infections, in particular viral infections in the liver where the PD-1 pathway is affected (see for example Kapoor and Kottilil 2014 Future Virol Vol. 9 pp. 565-585 and Salem and El-Badawy 2015 World J Hepatol Vol. 7 pp. 2449-2458). Viral liver infections can be selected from the group consisting of hepatitis viruses, in particular HBV, HCV and HDV, in particular chronic forms of these infections. In one embodiment the oligonucleotides or oligonucleotide conjugates or pharmaceutical compositions of the present invention are used to treat HBV, in particular chronic HBV. Indicators of chronic HBV infections are high levels of viral load (HBV DNA) and even higher levels of empty HBsAg particles (>100-fold in excess of virions) in the circulation.

Oligonucleotides or oligonucleotide conjugates of the present invention can also be used to treat viral liver infections that occur as co-infections with HIV. Other viral infections which can be treated with the oligonucleotides or oligonucleotide conjugates or pharmaceutical compositions of the present invention are lcmv (Lymphocytic Choriomeningitis Virus), and HIV as a mono infection, HSV-1 and -2, and other herpesviruses. These viruses are not hepatotrophic, however they may be sensitive to PDL1 down regulation.

In some embodiments the restoration of immunity or immune response involves improvement of the T-cell and/or NK cell response and/or alleviation of the T-cell exhaustion, in particular the HBV-specific T-cell response, the HCV-specific T-cell response and or the HDV-specific T-cell response is restored. An improvement of the T cell response can for example be assessed as an increase in T cells in the liver, in particular an increase in CD8+ and/or CD4+ T cells when compared to a control (e.g. the level prior to treatment or the level in a vehicle treated subject) In a further embodiment it is the virus specific CD8+ T cells that are restored or increased when compared to control), in particular HBV specific CD8+ T cells or HCV specific CD8+ T cells or HDV specific CD8+ T cells are restored or increased when compared to control. In a preferred embodiment CD8+ T cells specific for HBV s antigen (HBsAg) and/or CD8+ T cells specific for HBV e antigen (HBeAg) and/or CD8+ T cells specific for HBV core antigen (HBcAg) are increased in subjects treated with an oligonucleotide, oligonucleotide conjugate or pharmaceutical composition of the present invention compared to control. Preferably the HBV antigen specific CD8+ T cells produce one or more cytokines, such as interferon-gamma (IFN-γ) or tumor necrosis factor alpha (TNF-α). The increase in CD8+ T cells described above is in particular observed in the liver. The increase described herein should be statistically significant when compared to a control. Preferably the increase is at least 20%, such as 25%, such as 50% such as 75% when compared to control. In another embodiment natural killer (NK) cells and/or natural killer T (NKT) cells are activated by the oligonucleotides or oligonucleotide conjugates of the present invention.

Oligonucleotides or oligonucleotide conjugates or pharmaceutical compositions of the present invention can be used in the treatment parasite infections, in particular parasite infections where the PD-1 pathway is affected (see for example Bhadra et al. 2012 J Infect Dis vol 206 pp. 125-134; Bhadra et al. 2011 Proc Natl Acad Sci USA Vol. 108 pp. 9196-9201; Esch et al. J Immunol vol 191 pp 5542-5550; Freeman and Sharpe 2012 Nat Immunol Vol 13 pp. 113-115; Gutierrez et al. 2011 Infect Immun Vol 79 pp. 1873-1881; Joshi et al. 2009 PLoS Pathog Vol 5 e1000431; Liang et al. 2006 Eur J Immunol Vol. 36 pp 58-64; Wykes et al. 2014 Front Microbiol Vol 5 pp 249). Parasite infections can be selected from the group consisting of malaria, toxoplasmosis, leishmaniasis and trypanosomiasis. Malaria infection is caused by protozoa of the genus Plasmodium , in particular of the species P. vivax, P. malariae and P. falciparum . Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii . Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania . Trypanosomiasis is caused by the protozoan of the genus Trypanosoma . Chaga disease which is the tropical form caused by the species Trypanosoma cruzi , and sleeping disease is caused by the species Trypanosoma brucei.

In some embodiments the restoration of immunity involves restoration of a parasite-specific T cell and NK cell response, in particular a Plasmodium -specific T-cell response, a Toxoplasma gondii -specific T-cell and NK cell response, a Leishmania -specific T-cell and NK cell response, a Trypanosoma cruzi -specific T-cell and NK cell response or a Trypanosoma brucei -specific T-cell and NK cell response. In a further embodiment it is the parasite-specific CD8+ T cell and NK cell response that is restored.

Administration

The oligonucleotides or pharmaceutical compositions of the present invention may be administered topical (such as, to the skin, inhalation, ophthalmic or otic) or enteral (such as, orally or through the gastrointestinal tract) or parenteral (such as, intravenous, subcutaneous, intra-muscular, intracerebral, intracerebroventricular or intrathecal).

In a preferred embodiment the oligonucleotide or pharmaceutical compositions of the present invention are administered by a parenteral route including intravenous, intraarterial, subcutaneous, intraperitoneal or intramuscular injection or infusion, intrathecal or intracranial, e.g. intracerebral or intraventricular, intravitreal administration. In one embodiment the active oligonucleotide or oligonucleotide conjugate is administered intravenously. In another embodiment the active oligonucleotide or oligonucleotide conjugate is administered subcutaneously.

In some embodiments, the oligonucleotide, oligonucleotide conjugate or pharmaceutical composition of the invention is administered at a dose of 0.1-15 mg/kg, such as from 0.1-10 mg/kg, such as from 0.2-10 mg/kg, such as from 0.25-10 mg/kg, such as from 0.1-5 mg/kg, such as from 0.2-5 mg/kg, such as from 0.25-5 mg/kg. The administration can be once a week, every 2 nd week, every third week or even once a month.

Combination Therapies

In some embodiments the oligonucleotide, oligonucleotide conjugate or pharmaceutical composition of the invention is for use in a combination treatment with another therapeutic agent. The therapeutic agent can for example be the standard of care for the diseases or disorders described above.

For the treatment of chronic HBV infections a combination of antiviral drugs and immune system modulators is recommended as standard of care. The antiviral drugs effective against HBV are for example nucleos(t)ide analogs. There are five nucleos(t)ide analogs licensed for therapy of HBV namely lamivudine (Epivir), adefovir (Hepsera), tenofovir (Viread), telbivudine (Tyzeka), entecavir (Baraclude) these are effective in suppressing viral replication (HBV DNA) but have no effect on HBsAg levels. Other antiviral drugs include ribavirin and an HBV antibody therapy (monoclonal or polyclonal). The immune system modulators can for example be interferon alpha-2a and PEGylated interferon alpha-2a (Pegasys) or TLR7 agonists (e.g. GS-9620) or therapeutic vaccines. IFN-α treatment show only very modest effect in reducing viral load, but result in some HBsAg decline, albeit very inefficiently (<10% after 48 week therapy).

The oligonucleotide or oligonucleotide conjugates of the present invention may also be combined with other antiviral drugs effective against HBV such as the antisense oligonucleotides described in WO2012/145697 and WO 2014/179629 or the siRNA molecules described in WO 2005/014806, WO 2012/024170, WO 2012/2055362, WO 2013/003520 and WO 2013/159109.

When the oligonucleotides or oligonucleotide conjugates of this invention are administered in combination therapies with other agents, they may be administered sequentially or concurrently to an individual. Alternatively, pharmaceutical compositions according to the present invention may be comprised of a combination of an oligonucleotide or oligonucleotide conjugate of the present invention in association with a pharmaceutically acceptable excipient, as described herein, and another therapeutic or prophylactic agent known in the art.

The following embodiments of the present invention may be used in combination with any other embodiments described herein.

1. An antisense oligonucleotide which comprises or consists of a contiguous nucleotide sequence of 10 to 30 nucleotides in length capable of reducing the expression of PD-1.

2. The oligonucleotide of embodiment 1, wherein the contiguous nucleotide sequence is at least 90% complementarity to a PD-L1 target nucleic acid.

3. The oligonucleotide of embodiment 1 or 2, wherein the contiguous nucleotide sequence is complementary to a target nucleic acid selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2 and/or SEQ ID NO: 3.

4. The oligonucleotide of embodiment 1 to 3, wherein the contiguous nucleotide sequence is complementary to a region within position 1 and 15720 on SEQ ID NO: 1.

5. The oligonucleotide of embodiment 1 to 4, wherein the oligonucleotide is capable of hybridizing to a target nucleic acid of selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2 and/or SEQ ID NO: 3 with a ΔG° below −10 kcal.

6. The oligonucleotide of embodiment 1 to 5, wherein the contiguous nucleotide sequence is complementary to a sub-sequence of the target nucleic acid, wherein the sub-sequence is selected from the group consisting of position 371-3068, 5467-12107, 15317-15720, 15317-18083, 15317-19511 and 18881-19494 on SEQ ID NO: 1.

7. The oligonucleotide of embodiment 6, wherein the sub-sequence is selected from the group consisting of position 7300-7333, 8028-8072, 9812-9859, 11787-11873 and 15690-15735 on SEQ ID NO: 1.

8. The oligonucleotide of embodiment 2 to 7, wherein the target nucleic acid is RNA.

9. The oligonucleotide of embodiment 8, wherein the RNA is mRNA.

10. The oligonucleotide of embodiment 9, wherein the mRNA is pre-mRNA or mature mRNA.

11. The oligonucleotide of embodiment 1-10, wherein the contiguous nucleotide sequence comprises or consists of at least 14 contiguous nucleotides, particularly 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 contiguous nucleotides.

12. The oligonucleotide of embodiment 1-10, wherein the contiguous nucleotide sequence comprises or consists of from 16 to 20 nucleotides.

13. The oligonucleotide of embodiment 1-10, wherein the oligonucleotide comprises or consists of 14 to 35 nucleotides in length.

14. The oligonucleotide of embodiment 13, wherein the oligonucleotide comprises or consists of 18 to 22 nucleotides in length.

15. The oligonucleotide of embodiment 1-14, wherein the oligonucleotide or contiguous nucleotide sequence is single stranded.

16. The oligonucleotide of embodiment 1-15, wherein the contiguous nucleotide sequence is complementary to a sub-sequence of the target nucleic acid, wherein the subsequence is selected from the group consisting of A7, A26, A43, A119, A142, A159, A160, A163, A169, A178, A179, A180, A189, A201, A202, A204, A214, A221, A224, A226, A243, A254, A258, 269, A274, A350, A360, A364, A365, A370, A372, A381, A383, A386, A389, A400, A427, A435 and A438.

17. The oligonucleotide of embodiment 16, wherein the subsequence is selected from the group consisting of A221, A360, A180, A160 and A269.

18. The oligonucleotide of embodiment 1-17, wherein the oligonucleotide is not siRNA and is not self-complementary.

19. The oligonucleotide of embodiment 1-18, wherein the contiguous nucleotide sequence comprises or consists of a sequence selected from SEQ ID NO: 5 to 743 or 771.

20. The oligonucleotide of embodiment 1-19, wherein the contiguous nucleotide sequence comprises or consists of a sequence selected from SEQ ID NO: 6, 8, 9, 13, 41, 42, 58, 77, 92, 111, 128, 151, 164, 166, 169, 171, 222, 233, 245, 246, 250, 251, 252, 256, 272, 273, 287, 292, 303, 314, 318, 320, 324, 336, 342, 343, 344, 345, 346, 349, 359, 360, 374, 408, 409, 415, 417, 424, 429, 430, 458, 464, 466, 474, 490, 493, 512, 519, 519, 529, 533, 534, 547, 566, 567, 578, 582, 601, 619, 620, 636, 637, 638, 640, 645, 650, 651, 652, 653, 658, 659, 660, 665, 678, 679, 680, 682, 683, 684, 687, 694, 706, 716, 728, 733, 734, and 735.

21. The oligonucleotide of embodiment 1-20, wherein the contiguous nucleotide sequence comprises or consists of a sequence selected from SEQ ID NO: 466, 640, 342, 287 and 566.

22. The oligonucleotide of embodiment 1-21 wherein the contiguous nucleotide sequence has zero to three mismatches compared to the target nucleic acid it is complementary to.

23. The oligonucleotide of embodiment 22, wherein the contiguous nucleotide sequence has one mismatch compared to the target nucleic acid.

24. The oligonucleotide of embodiment 22, wherein the contiguous nucleotide sequence has two mismatches compared to the target nucleic acid.

25. The oligonucleotide of embodiment 22, wherein the contiguous nucleotide sequence is fully complementary to the target nucleic acid sequence.

26. The oligonucleotide of embodiment 1-25, comprising one or more modified nucleosides.

27. The oligonucleotide of embodiment 26, wherein the one or more modified nucleoside is a high-affinity modified nucleosides.

28. The oligonucleotide of embodiment 26 or 27, wherein the one or more modified nucleoside is a 2′ sugar modified nucleoside.

29. The oligonucleotide of embodiment 28, wherein the one or more 2′ sugar modified nucleoside is independently selected from the group consisting of 2′-O-alkyl-RNA, 2′-O-methyl-RNA, 2′-alkoxy-RNA, 2′-O-methoxyethyl-RNA, 2′-amino-DNA, 2′-fluoro-DNA, 2′-fluoro-ANA and LNA nucleosides.

30. The oligonucleotide of embodiment 28, wherein the one or more modified nucleoside is a LNA nucleoside.

31. The oligonucleotide of embodiment 30, wherein the modified LNA nucleoside is oxy-LNA.

32. The oligonucleotide of embodiment 31, wherein the modified nucleoside is beta-D-oxy-LNA.

33. The oligonucleotide of embodiment 30, wherein the modified nucleoside is thio-LNA.

34. The oligonucleotide of embodiment 30, wherein the modified nucleoside is amino-LNA.

35. The oligonucleotide of embodiment 30, wherein the modified nucleoside is cET.

36. The oligonucleotide of embodiment 30, wherein the modified nucleoside is ENA.

37. The oligonucleotide of embodiment 30, wherein the modified LNA nucleoside is selected from beta-D-oxy-LNA, alpha-L-oxy-LNA, beta-D-amino-LNA, alpha-L-amino-LNA, beta-D-thio-LNA, alpha-L-thio-LNA, (S)cET, (R)cET beta-D-ENA and alpha-L-ENA.

38. The oligonucleotide of embodiment 30-37, wherein there in addition to the modified LNA nucleoside is at least one 2′ substituted modified nucleoside.

39. The oligonucleotide of embodiment 38, wherein the 2′ substituted modified nucleoside is selected from the group consisting of 2′-O-alkyl-RNA, 2′-O-methyl-RNA, 2′-alkoxy-RNA, 2′-O-methoxyethyl-RNA (MOE), 2′-amino-DNA, 2′-fluoro-DNA, 2′-fluoro-ANA.

40. The oligonucleotide of any one of embodiments 1-39, wherein the oligonucleotide comprises at least one modified internucleoside linkage.

41. The oligonucleotide of embodiment 40, wherein the modified internucleoside linkage is nuclease resistant.

42. The oligonucleotide of embodiment 40 or 41, wherein at least 50% of the internucleoside linkages within the contiguous nucleotide sequence are phosphorothioate internucleoside linkages or boranophosphate internucleoside linkages.

43. The oligonucleotide of embodiment 40 or 41, wherein all the internucleoside linkages within the contiguous nucleotide sequence are phosphorothioate internucleoside linkages.

44. The oligonucleotide of embodiment 1-43, wherein the oligonucleotide is capable of recruiting RNase H.

45. The oligonucleotide of embodiment 44, wherein the oligonucleotide is a gapmer.

46. The oligonucleotide of embodiment 44 or 45, wherein the oligonucleotide is a gapmer of formula 5′-F-G-F′-3′, where region F and F′ independently comprise or consist of 1-7 modified nucleosides and G is a region between 6 and 16 nucleosides which are capable of recruiting RNaseH.

47. The oligonucleotide of embodiment 44 or 45, wherein the gapmer has formula 5′-D′-F-G-F′-3′ or 5′-F-G-F′-D″-3′, where region F and F′ independently comprise 1-7 modified nucleosides, G is a region between 6 and 16 nucleosides which are capable of recruiting RNaseH and region D′ or D″ comprise 1-5 phosphodiester linked nucleosides.

48. The oligonucleotide of embodiment 47, wherein D′ or D″ are optional.

49. The oligonucleotide of embodiment 47, wherein region D′ consist of two phosphodiester linked nucleosides.

50. The oligonucleotide of embodiment 49, wherein the phosphodiester linked nucleosides are ca (cytidine-adenosine).

51. The oligonucleotide of embodiment 46 or 47, wherein the modified nucleoside is a 2′ sugar modified nucleoside independently selected from the group consisting of 2′-O-alkyl-RNA, 2′-O-methyl-RNA, 2′-alkoxy-RNA, 2′-O-methoxyethyl-RNA, 2′-amino-DNA, 2′-fluoro-DNA, arabino nucleic acid (ANA), 2′-fluoro-ANA and LNA nucleosides.

52. The oligonucleotide of embodiments 46 to 51, wherein one or more of the modified nucleosides in region F and F′ is a LNA nucleoside.

53. The oligonucleotide of embodiment 52, wherein all the modified nucleosides in region F and F′ are LNA nucleosides.

54. The oligonucleotide of embodiment 53, wherein region F and F′ consist of LNA nucleosides.

55. The oligonucleotide of embodiment 52-54, wherein all the modified nucleosides in region F and F′ are oxy-LNA nucleosides.

56. The oligonucleotide of embodiment 52, wherein at least one of region F or F′ further comprises at least one 2′ substituted modified nucleoside independently selected from the group consisting of 2′-O-alkyl-RNA, 2′-O-methyl-RNA, 2′-alkoxy-RNA, 2′-O-methoxyethyl-RNA, 2′-amino-DNA and 2′-fluoro-DNA.

57. The oligonucleotide of embodiment 46-56, wherein the RNaseH recruiting nucleosides in region G are independently selected from DNA, alpha-L-LNA, C4′ alkylated DNA, ANA and 2′F-ANA and UNA.

58. The oligonucleotide of embodiment 57, wherein the nucleosides in region G is DNA and/or alpha-L-LNA nucleosides.

59. The oligonucleotide of embodiment 57 or 58, wherein region G consists of at least 75% DNA nucleosides.

60. The oligonucleotide of embodiment 1-59, wherein the oligonucleotide is selected from any one of the CMP ID NO: 5_1 to 743_1 and 771_1 (table 5).

61. The oligonucleotide of embodiment 1-60, wherein the oligonucleotide is selected from the group consisting of CMP ID NO: 6_1, 8_1, 9_1, 13_1, 41_1, 42_1, 58_1, 77_1, 92_1, 111_1, 128_1, 151_1, 164_1, 166_1, 169_1, 171_1, 222_1, 233_1, 245_1, 246_1, 250_1, 251_1, 252_1, 256_1, 272_1, 273_1, 287_1, 292_1, 303_1, 314_1, 318_1, 320_1, 324_1, 336_1, 342_1, 343_1, 344_1, 345_1, 346_1, 349_1, 359_1, 360_1, 374_1, 408_1, 409_1, 415_1, 417_1, 424_1, 429_1, 430_1, 458_1, 464_1, 466_1, 474_1, 490_1, 493_1, 512_1, 519_1, 519_1, 529_1, 533_1, 534_1, 547_1, 566_1, 567_1, 578_1, 582_1, 601_1, 619_1, 620_1, 636_1, 637_1, 638_1, 640_1, 645_1, 650_1, 651_1, 652_1, 653_1, 658_1, 659_1, 660_1, 665_1, 678_1, 679_1, 680_1, 682_1, 683_1, 684_1, 687_1, 694_1, 706_1, 716_1, 728_1, 733_1, 734_1, and 735_1.

62. The oligonucleotide of embodiment 1-61, wherein the oligonucleotide is selected from the group consisting of CMP ID NO: 287_1, 342_1, 466_1, 640_1, 566_1, 766_1, 767_1, 768_1, 769_1 and 770_1.

63. An antisense oligonucleotide conjugate comprising

a. an oligonucleotide according to any one of claims 1-62 (Region A); and b. at least one at least one conjugate moiety (Region C) covalently attached to said oligonucleotide.

64. The oligonucleotide conjugate of embodiment 63, wherein the conjugate moiety is selected from carbohydrates, cell surface receptor ligands, drug substances, hormones, lipophilic substances, polymers, proteins, peptides, toxins, vitamins, viral proteins or combinations thereof.

65. The oligonucleotide conjugate of embodiment 63 or 64, wherein the conjugate moiety is a carbohydrate containing moiety.

66. The oligonucleotide conjugate of embodiment 65, wherein the carbohydrate conjugate moiety comprises at least one asialoglycoprotein receptor targeting moiety covalently attached to an oligonucleotide according to any one of claims 1-62.

67. The oligonucleotide conjugate of embodiment 66, wherein the asialoglycoprotein receptor targeting conjugate moiety comprises at least one carbohydrate moiety selected from group consisting of galactose, galactosamine, N-formyl-galactosamine, N-acetylgalactosamine, N-propionyl-galactosamine, N-n-butanoyl-galactosamine and N-isobutanoylgalactosamine.

68. The oligonucleotide conjugate of embodiment 66 or 67, wherein the asialoglycoprotein receptor targeting conjugate moiety is mono-valent, di-valent, tri-valent or tetra-valent.

69. The oligomer conjugate of embodiment 68, wherein the asialoglycoprotein receptor targeting conjugate moiety consists of two to four terminal GalNAc moieties, a PEG spacer linking each GalNAc moiety to a brancher molecule.

70. The oligonucleotide conjugate of embodiment 66 to 69, wherein the asialoglycoprotein receptor targeting conjugate moiety is a tri-valent N-acetylgalactosamine (GalNAc) moiety.

71. The oligonucleotide conjugate of embodiment 66 to 70, wherein the conjugate moiety is selected from one of the trivalent GalNAc moieties in FIG. 1 .

72. The oligonucleotide conjugate of embodiment 71, wherein the conjugate moiety is the trivalent GalNAc moiety in FIG. 3 .

73. The oligonucleotide conjugate of embodiment 63-72, where a linker is present between the oligonucleotide or contiguous oligonucleotide sequence and the conjugate moiety.

74. The oligonucleotide conjugate of embodiment 73, wherein the linker is a physiologically labile linker (region B).

75. The oligonucleotide conjugate of embodiment 74, wherein the physiologically labile linker is nuclease susceptible linker.

76. The oligonucleotide conjugate of embodiment 74 or 75, wherein the physiologically labile linker is composed of 2 to 5 consecutive phosphodiester linkages.

77. The oligonucleotide conjugate of embodiment 76, wherein the physiologically labile linker is equivalent to region D′ or D″ presented in embodiment 47 to 50.

78. The oligonucleotide conjugate of any one of embodiments 63-77, wherein the oligonucleotide conjugate is selected from CMP ID NO: 766_2, 767_2,768_2, 769_2 and 770_2.

79. The oligonucleotide conjugate of embodiment 78, wherein the oligonucleotide conjugate is selected from the oligonucleotide conjugated represented in FIGS. 4, 5, 6, 7 and 8 .

80. The oligonucleotide conjugate of embodiment 63-76, which display improved inhibition of PD-L1 in the target cell, or improved cellular distribution between liver and the spleen or improved cellular uptake into the liver of the conjugate oligonucleotide as compared to an unconjugated oligonucleotide.

81. A pharmaceutical composition comprising the oligonucleotide of embodiment 1-62 or a conjugate of embodiment 63-80 and a pharmaceutically acceptable diluent, carrier, salt and/or adjuvant.

82. A method for manufacturing the oligonucleotide of embodiment 1-62, comprising reacting nucleotide units thereby forming covalently linked contiguous nucleotide units comprised in the oligonucleotide.

83. The method of embodiment 82, further comprising reacting the contiguous nucleotide sequence with a non-nucleotide conjugation moiety.

84. A method for manufacturing the composition of embodiment 81, comprising mixing the oligonucleotide with a pharmaceutically acceptable diluent, carrier, salt and/or adjuvant.

85. An in vivo or in vitro method for modulating PD-L1 expression in a target cell which is expressing PD-L1, said method comprising administering an oligonucleotide of embodiment 1-62 or a conjugate of embodiment 63-80 or the pharmaceutical composition of embodiment 81 in an effective amount to said cell.

86. A method for treating or preventing a disease comprising administering a therapeutically or prophylactically effective amount of an oligonucleotide of embodiment 1-62 or a conjugate of embodiment 63-80 or the pharmaceutical composition of embodiment 81 to a subject suffering from or susceptible to the disease.

87. A method for restoration of immunity against a virus or parasite comprising administering a therapeutically or prophylactically effective amount of an oligonucleotide conjugate of embodiment 63-80 or the oligonucleotide of embodiment 1-62 or the pharmaceutical composition of embodiment 81 to a subject infected with a virus or parasite.

88. The method of embodiment 87, the restoration of immunity is an increase in the liver of CD8+ T cells specific to one or more HBV antigens when compared to a control.

89. The oligonucleotide of embodiment 1-62 or a conjugate of embodiment 63-80 or the pharmaceutical composition of embodiment 81, for use as a medicament for treatment or prevention of a disease in a subject.

90. Use of the oligonucleotide of oligonucleotide of embodiment 1-62 or a conjugate of embodiment 63-80 for the preparation of a medicament for treatment or prevention of a disease in a subject.

91. The oligonucleotide of embodiment 1-62 or a conjugate of embodiment 63-80 or the pharmaceutical composition of embodiment 81, for use in restoration of immunity against a virus or parasite.

92. The use of embodiment 91, wherein the restoration of immunity is an increase in the liver of CD8+ T cells specific to one or more HBV antigens when compared to a control.

93. The use of embodiment 92, wherein the HBV antigen is the HBsAg.

94. The method, the oligonucleotide or the use of embodiments 86-93, wherein the disease is associated with in vivo activity of PD-1.

95. The method, the oligonucleotide or the use of embodiments 86-94, wherein the disease is associated with increased expression of PD-L1 in an antigen presenting cell.

96. The method, the oligonucleotide or the use of embodiments 95, wherein the PD-L1 is reduced by at least 30%, or at least or at least 40%, or at least 50%, or at least 60%, or at least 70%, or at least 80%, or at least 90%, or at least 95% compared to the expression without or before treatment with the oligonucleotide of embodiment 1-62 or a conjugate of embodiment 63-80 or the pharmaceutical composition of embodiment 81.

97. The method, the oligonucleotide or the use of embodiments 86-95, wherein the disease is selected from a viral liver infection or a parasite infections.

98. The method, the oligonucleotide or the use of embodiment 98, wherein the viral infection is HBV, HCV or HDV.

99. The method, the oligonucleotide or the use of embodiment 86-95, wherein the disease is chronic HBV.

100. The method, the oligonucleotide or the use of embodiment 98, wherein the parasite infection is malaria, toxoplasmosis, leishmaniasis or trypanosomiasis.

101. The method, the oligonucleotide or the use of embodiments 86-100, wherein the subject is a mammal.

102. The method, the oligonucleotide or the use of embodiment 101, wherein the mammal is human.

Materials and Methods

Motif Sequences and Oligonucleotide Compounds

Designs refer to the gapmer design, F-G-F′, where each number represents the number of consecutive modified nucleosides, e.g. 2′ modified nucleosides (first number=5′ flank), followed by the number of DNA nucleosides (second number=gap region), followed by the number of modified nucleosides, e.g. 2′ modified nucleosides (third number=3′ flank), optionally preceded by or followed by further repeated regions of DNA and LNA, which are not necessarily part of the contiguous sequence that is complementary to the target nucleic acid.

Oligonucleotide compounds represent specific designs of a motif sequence. Capital letters represent beta-D-oxy LNA nucleosides, lowercase letters represent DNA nucleosides, all LNA C are 5-methyl cytosine, all internucleoside linkages are phosphorothioate internucleoside linkages.

Designs refer to the gapmer design, F-G-F′, where each number represents the number of consecutive modified nucleosides, e.g. 2′ modified nucleosides (first number=5′ flank), followed by the number of DNA nucleosides (second number=gap region), followed by the number of modified nucleosides, e.g. 2′ modified nucleosides (third number=3′ flank), optionally preceded by or followed by further repeated regions of DNA and LNA, which are not necessarily part of the contiguous sequence that is complementary to the target nucleic acid.

Oligonucleotide compounds represent specific designs of a motif sequence. Capital letters represent beta-D-oxy LNA nucleosides, lowercase letters represent DNA nucleosides, all LNA C are 5-methyl cytosine, all internucleoside linkages are phosphorothioate internucleoside linkages.

Capital letters represent beta-D-oxy LNA nucleosides, lowercase letters represent DNA nucleosides, all LNA C are 5-methyl cytosine, subscript o represent a phosphodiester internucleoside linkage and unless otherwise indicated other internucleoside linkages are phosphorothioate internucleoside linkages.

GN2 represents the trivalent GalNAc cluster shown in FIG. 3 , C6 represents an amino alkyl group with 6 carbons, capital letters represent beta-D-oxy LNA nucleosides, lowercase letters represent DNA nucleosides, all LNA C are 5-methyl cytosine, subscript o represent a phosphodiester nucleoside linkage and unless otherwise indicated internucleoside linkages are phosphorothioate internucleoside linkages. Chemical drawings representing some of the molecules are shown in FIGS. 4 to 8 .

AAV/HBV Mouse Models

Pasteur Model:

HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-knockout (here referred to as HLA-A2/DR1) mice were created and bred at the Institut Pasteur. These mice represent an in vivo experimental model for human immune function studies without any interference with mouse MHC response (Pajot et al 2004 Eur J Immunol. 34(11):3060-9.

Adeno-associated virus (AAV) vector, AAV serotype 2/8 carrying a replication competent HBV DNA genome was used in these studies. The AAV-HBV vector (batch GVPN #6163) was diluted in sterile Phosphate buffered Saline (PBS) to reach a titer of 5×10 11 vg/mL. Mice were injected intravenously (i.v.) with 100 μL of this diluted solution (dose/mouse: 5×10 10 vg) in a tail vein. Complete viral particles containing HBV DNA were detected in the blood of HBV-carrier mice. HBcAg was detected for up to one year in the liver together with HBV circulating proteins HBeAg and HBsAg in the blood. In all AAV2/8-HBV-transduced mice, HBsAg, HBeAg, and HBV DNA persisted in serum for at least one year (Dion et al 2013 J Virol 87:5554-5563).

Shanghai Model:

In this model, mice infected with a recombinant adeno-associated virus (AAV) carrying the HBV genome (AAV/HBV) maintains stable viremia and antigenimia for more than 30 weeks (Dan Yang, et al. 2014 Cellular & Molecular Immunology 11, 71-78).

Male C57BL/6 mice (4-6 weeks old), specific pathogen free, were purchased from SLAC (Shanghai Laboratory Animal Center of Chinese Academy of Sciences) and housed in an animal care facility in individually ventilated cages. Guidelines were followed for the care and use of animals as indicated by WuXi IACUC (Institutional Animal Care and Use Committee, WUXI IACUC protocol number R20131126-Mouse). Mice were allowed to acclimate to the new environment for 3 days and are grouped according to the experimental design.

Recombinant AAV-HBV was diluted in PBS, 200 μL per injection. This recombinant virus carries 1.3 copies of the HBV genome (genotype D, serotype ayw).

On day 0, all mice were injected through tail vein with 200 μL AAV-HBV. On days 6, 13 and 20 after AAV injection, all mice in were submandibularly bled (0.1 ml blood/mouse) for serum collection. On day 22 post injection, mice with stable viremia were ready for oligonucleotide treatment. The oligonucleotides can be unconjugated or GalNAc conjugated.

DNA Vaccine

Plasmid DNA were endotoxin-free and manufactured by Plasmid-Factory (Germany). pCMV-S2.S ayw encodes the preS2 and S domains of the HBsAg (genotype D), and its expression is controlled by the cytomegalovirus immediate early gene promoter (Michel et al 1995 Proc Natl Acad Sci USA 92:5307-5311). pCMV-HBc encodes the HBV capsid carrying the hepatitis core (HBc) Ag (Dion et al 2013 J Virol 87:5554-5563).

Treatment with DNA vaccine was conducted as described here. Five days prior to vaccination cardiotoxine (CaTx, Latoxan refL81-02, 50 μl/muscle) was injected into the muscle of the mice. CaTx depolarizees the muscular fibers to induce cell degeneration, 5 days post injection, new muscular fibers will appear and will receive the DNA vaccine for a better efficacy for transfection. The pCMV-S2.S ayw and pCMVCore at 1 mg/ml each were mixed in equal amount and each mouse received a total of 100 μg by bilateral intramuscular injection into cardiotoxin-treated tibialis anterior muscles as previously described in Michel et al 1995 Proc Natl Acad Sci USA 92:5307-5311, under anesthesia (100 μL of 12.5 mg/mL ketamine, 1.25 mg/mL xylazine).

Anti-PD-L1 Antibody

This is a mouse anti mouse PD-L1 IgG1 antibody clone 6E11 internally produced at Genetech. It is a surrogate antibody that cross blocks Atezolizumab and has similar in vitro blocking activity Atezolizumab produced internally at Roche. The antibody was administered by intraperitoneal (i.p.) injection at a dose of 12.5 μg/g.

Oligonucleotide Synthesis

Oligonucleotide synthesis is generally known in the art. Below is a protocol which may be applied. The oligonucleotides of the present invention may have been produced by slightly varying methods in terms of apparatus, support and concentrations used.

Oligonucleotides are synthesized on uridine universal supports using the phosphoramidite approach on an Oligomaker 48 at 1 μmol scale. At the end of the synthesis, the oligonucleotides are cleaved from the solid support using aqueous ammonia for 5-16 hours at 60° C. The oligonucleotides are purified by reverse phase HPLC (RP-HPLC) or by solid phase extractions and characterized by UPLC, and the molecular mass is further confirmed by ESI-MS.

Elongation of the Oligonucleotide:

The coupling of β-cyanoethyl-phosphoramidites (DNA-A(Bz), DNA-G(ibu), DNA-C(Bz), DNA-T, LNA-5-methyl-C(Bz), LNA-A(Bz), LNA-G(dmf), or LNA-T) is performed by using a solution of 0.1 M of the 5′-O-DMT-protected amidite in acetonitrile and DCI (4,5-dicyanoimidazole) in acetonitrile (0.25 M) as activator. For the final cycle a phosphoramidite with desired modifications can be used, e.g. a C6 linker for attaching a conjugate group or a conjugate group as such. Thiolation for introduction of phosphorthioate linkages is carried out by using xanthane hydride (0.01 M in acetonitrile/pyridine 9:1). Phosphordiester linkages can be introduced using 0.02 M iodine in THF/Pyridine/water 7:2:1. The rest of the reagents are the ones typically used for oligonucleotide synthesis.

For post solid phase synthesis conjugation a commercially available C6 amino linker phosphoramidite can be used in the last cycle of the solid phase synthesis and after deprotection and cleavage from the solid support the aminolinked deprotected oligonucleotide is isolated. The conjugates are introduced via activation of the functional group using standard synthesis methods.

Alternatively, the conjugate moiety can be added to the oligonucleotide while still on the solid support by using a GalNAc- or GalNAc-cluster phosphoramidite as described in PCT/EP2015/073331 or in EP appl. NO. 15194811.4.

Purification by RP-HPLC:

The crude compounds are purified by preparative RP-HPLC on a Phenomenex Jupiter C18 10μ 150×10 mm column. 0.1 M ammonium acetate pH 8 and acetonitrile is used as buffers at a flow rate of 5 mL/min. The collected fractions are lyophilized to give the purified compound typically as a white solid.

DCI: 4,5-Dicyanoimidazole

DCM: Dichloromethane

DMF: Dimethylformamide

DMT: 4,4′-Dimethoxytrityl

THF: Tetrahydrofurane

Bz: Benzoyl

Ibu: Isobutyryl

RP-HPLC: Reverse phase high performance liquid chromatography

T m Assay

Oligonucleotide and RNA target (phosphate linked, PO) duplexes are diluted to 3 mM in 500 ml RNase-free water and mixed with 500 ml 2×T m -buffer (200 mM NaCl, 0.2 mM EDTA, 20 mM Naphosphate, pH 7.0). The solution is heated to 95° C. for 3 min and then allowed to anneal in room temperature for 30 min. The duplex melting temperatures (T m ) is measured on a Lambda 40 UV/VIS Spectrophotometer equipped with a Peltier temperature programmer PTP6 using PE Templab software (Perkin Elmer). The temperature is ramped up from 20° C. to 95° C. and then down to 25° C., recording absorption at 260 nm. First derivative and the local maximums of both the melting and annealing are used to assess the duplex T m .

Tissue Specific In Vitro Linker Cleavage Assay

FAM-labeled oligonucleotides with the biocleavable linker to be tested (e.g. a DNA phosphodiester linker (PO linker)) are subjected to in vitro cleavage using homogenates of the relevant tissues (e.g. liver or kidney) and Serum.

The tissue and serum samples are collected from a suitable animal (e.g. mice, monkey, pig or rat) and homogenized in a homogenisation buffer (0.5% Igepal CA-630, 25 mM Tris pH 8.0, 100 mM NaCl, pH 8.0 (adjusted with 1 N NaOH). The tissue homogenates and Serum are spiked with oligonucleotide to concentrations of 200 μg/g tissue. The samples are incubated for 24 hours at 37° C. and thereafter the samples are extracted with phenol-chloroform. The solutions are subjected to AIE HPLC analyses on a Dionex Ultimate 3000 using an Dionex DNApac p-100 column and a gradient ranging from 10 mM-1 M sodium perchlorate at pH 7.5. The content of cleaved and non-cleaved oligonucleotide are determined against a standard using both a fluorescence detector at 615 nm and a uv detector at 260 nm.

S1 Nuclease Cleavage Assay

FAM-labelled oligonucleotides with S1 nuclease susceptible linkers (e.g. a DNA phosphodiester linker (PO linker)) are subjected to in vitro cleavage in S1 nuclease extract or Serum.

100 μM of the oligonucleotides are subjected to in vitro cleavage by S1 nuclease in nuclease buffer (60 U pr. 100 μL) for 20 and 120 minutes. The enzymatic activity is stopped by adding EDTA to the buffer solution. The solutions are subjected to AIE HPLC analyses on a Dionex Ultimate 3000 using an Dionex DNApac p-100 column and a gradient ranging from 10 mM-1 M sodium perchlorate at pH 7.5. The content of cleaved and non-cleaved oligonucleotide is determined against a standard using both a fluorescence detector at 615 nm and a uv detector at 260 nm.

Preparation of Liver Mononuclear Cells

Liver cells from AAV/HBV mice were prepared as described below and according to a method described by Tupin et al 2006 Methods Enzymol 417:185-201 with minor modifications. After mouse euthanasia, the liver was perfused with 10 ml of sterile PBS via hepatic portal vein using syringe with G25 needle. When organ is pale, the organ was harvested in Hank's Balanced Salt Solution (HBSS) (GIBCO® HBSS, 24020)+5% decomplemented fetal calf serum (FCS). The harvested liver was gently pressed through 100 μm cell-strainer (BD Falcon, 352360) and cells were suspended in 30 ml of HBSS+5% FCS. Cell suspension was centrifuged at 50 g for 5 min. Supernatants were then centrifuged at 289 g for 10 min at 4° C. After centrifugation, supernatants were discarded and pellets were re-suspended in 15 mL at room temperature in a 35% isotonic Percoll solution (GE Healthcare Percoll #17-0891-01 diluted into RPMI 1640 (GIBCO, 31870)) and transferred to a 15 ml tube. Cells were further centrifuged at 1360 g for 25 min at room temperature. The supernatant was discarded by aspiration and the pellet containing mononuclear cells was washed twice with HBSS+5% FCS.

Cells were cultured in complete medium (α-minimal essential medium (Gibco, 22571) supplemented with 10% FCS (Hyclone, #SH30066, lot APG21570), 100 U/mL penicillin+100 μg/mL streptomycin+0.3 mg/mL L-glutamine (Gibco, 10378), 1× non-essential amino acids (Gibco, 11140), 10 mM Hepes (Gibco, 15630), 1 mM sodium pyruvate (Gibco, 11360) and 50 μM β-mercaptoethanol (LKB, 1830)).

Surface Labeling of Cells

Cells were seeded in U-bottom 96-well plates and washed with PBS FACS (PBS containing 1% bovine serum albumin and 0.01% sodium azide). Cells were incubated with 5 μL of PBS FACS containing a rat anti-mouse CD16/CD32 antibody and a viability marker LD fixable yellow, Thermofisher, L34959 for 10 min in the dark at 4° C. Then, cells were stained for 20 min in the dark at 4° C. with 25 μL of PBS FACS containing monoclonal antibodies (Mab) against NK P46 BV421 (Rat Mab anti mouse NK P46, Biolegend, 137612) and F4/80 (rat Mab anti-mouse F4/80 FITC, BD Biolegend, 123108) and two supplemental surface markers: PD1 (rat Mab anti-mouse PD1 PE, BD Biosciences, 551892) and PDL1 (rat Mab anti-mouse PDL1 BV711, Biolegend, 124319) were also added.

Intracelluar Cytokine Staining (ICS) Assay

ICS assays were performed on both splenocytes and liver mononuclear cells. Cells were seeded in Ubottom 96-well plates. Plates with cells were incubated overnight at 37° C. either in complete medium alone as negative control or with the peptides described in Table 9 at a concentration of 2 μg/ml. Brefeldin A at 2 μg/mL (Sigma, B6542) was added after one hour of incubation.

After the overnight culture, cells were washed with PBS FACS and incubated with 5 μL of PBS FACS containing rat anti-mouse CD16/CD32 antibody and a viability marker LD fixable yellow, Thermofisher, L34959 for 10 min in the dark at 4° C. Then, cells were stained for 20 min in the dark at 4° C. with 25 μL of PBS FACS containing Mab. The mix was composed of monoclonal antibodies against CD3 (hamster Mab anti-mouse CD3-PerCP, BD Biosciences, 553067), CD8 (rat Mab anti-mouse CD8-APC-H7, BD Biosciences, 560182), CD4 (rat Mab anti-mouse CD4-PE-Cy7, BD Biosciences, 552775), and NK cells (Rat Mab anti mouse NK P46 BV421, Biolegend, 137612). Cells were fixed after several washes and permeabilized for 20 min in the dark at room temperature with Cytofix/Cytoperm, washed with Perm/Wash solution (BD Biosciences, 554714) at 4° C.

Intracellular cytokine staining with antibodies against IFNγ (rat Mab anti-mouse IFNγ-APC, clone XMG1.2, BD Biosciences, 554413) and tumor necrosis factor alpha (TNFα) (rat Mab anti-mouse TNFα-FITC, clone MP6-XT22; 1/250 (BD Biosciences 554418) was performed for 30 min in the dark at 4° C. Before analysis by flow cytometry using the MACSQuant Analyzer, cells were washed with Perm/Wash and re-suspended in PBS FACS containing 1% Formaldehyde.

Live CD3+CD8+CD4− and cells CD3+CD8−CD4+ were gated and presented on dot-plot. Two regions were defined to gate for positive cells for each cytokine. Numbers of events found in these gates were divided by total number of events in parental population to yield percentages of responding T cells. For each mouse, the percentage obtained in medium alone was considered as background and subtracted from the percentage obtained with peptide stimulations.

Threshold of positivity was defined according to experiment background i.e. the mean percentage of stained cells obtained for each group in medium alone condition plus two standard deviations. Only percentage of cytokine represented at least 5 events were considered as positive.

Reverse (R3_core):

(SEQ ID NO: 785)

Probe (P3_core):

(SEQ ID NO: 786)

56-FAM-AGC TCC AAA/ZEN/TTC TTT ATA AGG GTC GAT GTC

CAT G-3IABkFQ

A standard curve using HBV plasmid (Genotype D, GTD) was prepared using 10-fold dilutions starting with 1×10 9 copies/μl down to 1 copy/μl and used in 5 μl per reaction.

For each reaction 10 μl Gene Expression Master Mix, 4.5 μl water, 0.5 μl Primer mix and 5 μl sample or standard was added and the qPCR was run.

For the analysis the copy number/ml/well was calculated using the standard curve. The results are shown in table 15.

PD-L1 mRNA expression was measured using qPCR.

mRNA was extracted from frozen liver pieces that were added to 2 ml tubes containing ceramic beads (Lysing Matrix D tubes, 116913500, mpbio) and 1 ml of Trizol.

The liver piece was homogenized using the Precellys Tissue Disruptor. 200 μl Chloroform was added to the homogenate, vortexed and centrifuged at 4° C. for 20 min at 10000 rpm. The RNA containing clear phase (around 500 ul) was transferred into a fresh tube and the same volume of 70% EtOH was added. After mixing well the solution was transferred onto a RNeasy spin column and RNA was further extracted following the RNeasy Kit's manual RNeasy Mini Kit, cat. #74104, Qiagen (including the RNA digestion RNase-free DNase Set, cat. #79254). Elution in 50 μl H 2 O. The final RNA concentration was measured and adjusted to 100 ng/ul for all samples.

The qPCR was conducted on 7.5 μl RNA using the Taqman RNA-to-ct 1-step Kit, cat. #4392938, Thermo Fisher according to the manufactures instructions. The fprimer mixed used contained PD-L1_1-3 (Primer number Mm00452054_m1, Mm03048247_m1 and Mm03048248_m1) and endogenous controls (ATCB Mm00607939_s1, CANX Mm00500330_m1, YWHAZ Mm03950126_s1 and GUSB Mm01197698_m1)

Data were analysed using the 2{circumflex over ( )}−ddct method. The mean of all four endogenous controls was used to calculate dct values. The PD-L1 expression relative to mean of the endogenous controls and in % of saline

From these results it can be seen that both naked and GalNAc conjugated oligonucleotides are capable of reducing PD-L1 mRNA expression in the liver of an AAV/HBV mouse, with the GalNAc conjugated oligonucleotide being somewhat better. Both oligonucleotides also resulted in some reduction in HBV DNA in the serum.