Amgen Inc. v. Amneal Pharmaceuticals LLC, No. 18-2414 (Fed. Cir. 2020)Annotate this Case
Amgen holds an approved New Drug Application for Sensipar®, a formulation of cinacalcet hydrochloride used to treat secondary hyperparathyroidism in adult patients with chronic kidney disease who are on dialysis and to treat hypercalcemia in patients with parathyroid cancer and primary and secondary hyperparathyroidism. Amneal, Piramal, and Zydus each filed an Abbreviated New Drug Application (ANDA) seeking to enter the market with a generic version of Sensipar®. Amgen sued each ANDA filer, alleging that the proposed ANDA products would infringe its 405 patent, which is directed to a rapid dissolution formulation of cinacalcet. The district court entered a judgment of non-infringement. The Federal Circuit vacated in part, finding that the district court construed the claims incorrectly and erred in its analysis of infringement by Amneal. The court affirmed with respect to Piramal and Zydus, finding that the district court properly applied prosecution history estoppel to Amgen’s arguments regarding Piramal and otherwise did not err in its factual findings for Zydus.