GRUNENTHAL GMBH v. ALKEM LABORATORIES LIMITED

Before Judges Reyna, Taranto, and Chen. Appeal from the U.S. District Court for the District of New Jersey.

Summary: There may be no reasonable expectation of success in producing a specific polymorph of a compound when that compound is not known to be polymorphic, and existing synthesizing methods do not necessarily produce or provide specific guidance for producing the specific polymorph.

Grünenthal sued several generic pharmaceutical companies for infringement of two patents directed to the drug, tapentadol hydrochloride, and methods of using it to treat polyneuropathic pain. After a bench trial, the district court concluded, among other things, that the compound patent is not invalid as obvious, and that two of the generic companies did not induce or contribute to the infringement of the method patent.

The Federal Circuit affirmed the district court’s finding of no induced or contributory infringement of the method patent.  In their request for approval to market generic tapentadol hydrochloride, the generic companies told the FDA that they would not be seeking approval for treatment of neuropathic pain.  The Federal Circuit agreed that the proposed drug labels did not instruct users to practice the claimed method because the instructions were limited to treating general chronic pain and omitted any clinical studies relating to neuropathic pain. The Federal Circuit also found that there was evidence to support the district court’s finding that the non-infringing uses of the proposed generic product were substantial.

With respect to the compound patent, which is directed to a Form A polymorph of the drug, the Federal Circuit affirmed the district court’s finding that a person of ordinary skill would not have had a reasonable expectation of success in discovering Form A from prior art references disclosing Form B and teaching general methods for screening for polymorphs.  The Federal Circuit reasoned that there was (1) no known or expected polymorphism of the drug, (2) no evidence that prior art methods for producing Form B would also produce Form A, and (3) no guidance as to what variables for discovering polymorphs would likely lead to the identification of Form A.

This case is: GRUNENTHAL GMBH v. ALKEM LABORATORIES LIMITED

Editor: Paul Stewart

Written by: Peter A. Hecker, Ph.D. and Karen M. Cassidy