Pfizer Wins Appeal of Summary Judgment Ruling in Neurontin Case

In re Gabapentin Patent Litigation, No. 2006-1572 (Fed. Cir. 2007)

Last Friday, the Court of Appeals for the Federal Circuit reversed a 2005 district court ruling granting summary judgment of noninfringement to several companies who sought to market generic versions of Pfizer's epilepsy drug Neurontin (gabapentin).  The district court had ruled on summary judgment that generic versions of Neurontin made by Teva, IVAX, and Eon did not infringe Pfizer's U.S. Patent No. 6,054,482, which covers a process for the preparation of, and compositions containing, gabapentin.

Claim 7 of the '482 patent is directed to a composition consisting essentially of gabapentin, containing "less than 20 ppm of an anion of a mineral acid . . . ."  The main issue on appeal was whether the defendants had shown, beyond dispute, that their generic gabapentin formulations do not meet the 20 ppm limitation.  According to the district court, Pfizer "failed to adduce sufficient evidence to establish that the accused products meet the limitation."  But on appeal, the Federal Circuit reviewed Pfizer's evidence and concluded that it was sufficient to raise a genuine issue of material fact, requiring resolution at trial.

It's amazing how long some Hatch-Waxman cases drag on.  This litigation has been active since at least 2000, when Warner-Lambert (now part of Pfizer) filed suit against the first of many ANDA applicants who filed paragraph IV certifications with respect to the '482 patent.  Between 2001 and 2003, the defendants filed various summary judgment motions, including for summary judgment of noninfringement and invalidity.  While those motions were pending, Warner-Lambert unsuccessfully sought a preliminary injunction to enjoin the defendants from launching their products at-risk.

Teva began selling its generic Neurontin in 2004, and others followed suit in 2005.  In the first half of 2004, before Teva launched, Pfizer's U.S. sales of Neurontin were $1.2 billion; in the first half of 2005, after Teva launched, Pfizer's sales were down to $91 million.  The '482 patent won't expire until 2017.  The case now goes back down to the district court, for a trial to determine whether Teva and the other generics will have to pay damages to compensate Pfizer for billions of dollars in lost sales.

RELATED READING:

• Bloomberg.com article
• Press releases: Pfizer; Teva