Pfizer Inc. et. al v. Teva Pharmaceuticals USA, Inc. et al. (Fed Cir)

Case Name: Pfizer Inc. et. al v. Teva Pharmaceuticals USA, Inc. et al., Civ. Nos. 2012-1576, 2012-1601, 2012-1602, 2012-1603, 2012-1604, 2012-1605, 2012-1607, 2014 U.S. App. LEXIS 2242 (Fed. Cir. February 6, 2014) (Circuit Judges Rader, Prost and Moore presiding; Opinion by Prost) (Appeal from D. Del., Sleet, J.) (Affirming construction of the term “4-amino-3-(2-methylpropyl) butanoic acid,” judgment of non-infringement based on that construction and validity of the patents.)

Drug Product and Patent(s)-in-Suit: Lyrica^® (pregabalin); U.S. Pat. No. 6,197,819 (“the ’819 patent”) and U.S. Reissue Patent No. 41,920 (“RE ’920 patent”)

Nature of the Case and Issue(s) Presented: Appellants challenged the district court’s claim construction of “4-amino-3-(2-methylpropyl) butanoic acid” and its finding that the patent was valid. The district court construed “4-amino-3-(2-methylpropyl) butanoic acid” to mean “the chemical compound 4-amino-3-(2-methylpropyl) butanoic acid” without limitation as to the stereochemical form.” Appellants argued that the district court erred in this construction by not limiting it only to the racemic mixture. Appellants stated that the specification, prosecution history, and applicant declarations supported a narrower construction. The Court rejected Appellants arguments because the plain language supports the broader reading and, while the specification only reported results of the racemate, there was no clear disavowal of claim scope. Appellant also challenged the district court’s findings that the patent was enabled, contained adequate written description and was nonobvious.  Appellant argued that the patent was not enabled since it did not disclose how to prepare every conceivable mixture of 4-amino-3-(2-methylpropyl) butanoic acid. The Court rejected this argument finding that methods for preparing or isolating enantiomers were well known in the art. Appellant also argued that the claims lacked written description support because the inventors failed to sufficiently describe the separating the racemate into its enantiomers. The Court rejected this argument affirming the district court’s finding that there was adequate disclosure, since the patent disclosed the structure of the compound, in vitro and in vivo data for the compound, and described a method of synthesizing the compound. The patentee was not required to reduce the practice every species of a genus claim. Finally, Appellant challenged the district court determination that the patent was not obvious. Appellants argued that the district court erred in failing to find (1) that the prior art taught that 3-isopropylGABA and other homologues had anticonvulsant activity; (2) that one of ordinary skill in the art would have expected 4-amino-3-(2-methylpropyl) butanoic acid to have anticonvulsant activity due to structural similarity to 2-isopropylGABA; and (3) gabapentin, another 3-alkylGABA compound would have provided motivation to try other alkyl substitutes at GABA’s 3-position.  The Court rejected Appellants arguments stating that Appellants obviousness evidence was too sparse.

Why Appellees Prevailed:  Appellee prevailed on infringement because the Court found no clear disavowal of claim scope regarding 4-amino-3-(2-methylpropyl) butanoic acid. The Court affirmed the claim construction because while the specification only discussed the racemate, there was no disavowal of other enantiomers. With respect to Appellants’ lack of enablement and written description arguments, the Court’s decision rested on the finding that one of ordinary skill in the art would understand how to separate enantiomers and the patentee is not required to disclose each and every permutation of the claims. Finally, on obviousness, Appellants failed to put forth sufficient evidence. To invalidate a compound patent, the court must identify a lead compound and find that the prior art would teach one of ordinary skill in the art to make “specific molecular modifications” to the lead compound with a reasonable expectation of success. According to the Court, Appellants did not adequately identify a lead compound and that the record only contains scant evidence that either gabapentin or 3-isopropylGABA would have been selected as a lead compound. Appellants also failed to identify teachings that would lead one of ordinary skill in the art to make “specific molecular modifications.” The prior art references disclosed trillions of compounds without calling out specific alkyl groups or singling out the isobutyl group. Furthermore, the prior art precluded any finding of a reasonable expectation of success since anticonvulsant drug discovery at the time of filing was “complicated,” “unpredictable” and “largely conducted through trial and error.”