by Dennis Crouch Amgen v. Amneal Pharma (Fed. Cir. 2020) Amgen’s patent at issue covers a drug formulation for treatment of hyperparathyroidism in particular situations sold under the trade name Sensipar with about $1b annual sales. U.S. Patent 9,375,405.  Note here, that Amgen’s primary patent on the blockbuster drug expired in 2018, but this secondary formulation patent … Continue reading Opening a Closed Markush Group