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Amgen Inc. v. Amneal Pharmaceuticals LLC

Fed Cir Corrects Over-Restrictive Interpretation of Markush Group

Amgen Inc. v. Amneal Pharmaceuticals LLC, __ F.3d __, 2020 WL 62012 (Fed. Cir. Jan. 7, 2020) (Newman, LOURIE, Taranto) (D. Del.: Goldberg) (3 of 5 stars)

Fed Cir vacates Hatch-Waxman noninfringement judgment as to Amneal, affirms noninfringement judgment as to Piramal Healthcare UK Ltd., and affirms infringement judgment as to Zydus Pharmaceuticals (USA) Inc. Amgen’s patent relates to a rapid dissolution formulation of cinacalcet, used to treat hyperparathyroidism for certain patients, and is listed in the Orange Book for Amgen’s Sensipar product.

Vacatur of judgment of no infringement by Amneal: The district court erred in construing the claim as foreclosing the presence of unclaimed constituents in two categories (binders and disintegrants) addressed by Markush groups. The claim’s structure, addressing a composition “comprising” various materials, including “at least one x selected from the group consisting of [y–z]” did not foreclose the presence of unrecited group members, so long as at least one recited member was present. Multilayer, 831 F.3d 1350 (Fed. Cir. 2016), is not contrary because it does not hold that any time “consisting” is used for a Markush group, components from outside that group are always precluded. “There is no language in Amgen’s claim indicating that every binder or disintegrant in the claimed formulation must be within the Markush groups. . . . The plain language of this claim requires “at least one” of the Markush members and certainly does not indicate that the only binders and disintegrants in the claimed formulation are those listed in the groups.” Op. at 17–18. Because the district court’s interpretation of the Markush groups was dispositive as to Amneal, the noninfringement judgment for Amneal is vacated. The district court also erred in determining whether Amneal’s product contained one of the listed binders. The record indicated that at least one of the listed binders was present; that another material may have been present, too, was not relevant.

Affirmance of judgment of no infringement by Piramal: The district court correctly applied prosecution history estoppel to bar Amgen’s invocation of the doctrine of equivalents against Piramal. The opinion describes how Amgen narrowed its claim during prosecution, and rejects Amgen’s contention that it was for a non-patentability reason. It also rejects Amgen’s attempt to invoke the tangential exception to prosecution history estoppel.

Affirmance of judgment of infringement by Zydus: The district court did not clearly err in rejecting Zydus’s attack on Amgen’s infringement proof. Though there were some problems in the opinions of Amgen’s expert, “the court was not required to reject all of [the expert’s] testimony once finding any individual part of it incorrect.” Op. at 27.

Though the district court had not resolved Zydus’s defense and counterclaim of invalidity, the judgment was nevertheless final and the Fed Cir has jurisdiction over Zydus’s cross-appeal because Zydus represented that it would give up its invalidity defense if infringement was affirmed.

KEYWORDS: HATCH-WAXMAN; CLAIM CONSTRUCTION; MARKUSH GROUP; PROSECUTION HISTORY ESTOPPEL; DOCTRINE OF EQUIVALENTS