Appeals Court Revives Amgen’s Sensipar Patent Challenge

The Federal Circuit Court of Appeals gave Amgen another chance to prove that Amneal’s planned generic of its hyperparathyroidism treatment Sensipar (cinacalcet) infringes on its patent.

Amgen filed suit against Amneal, Piramal Healthcare UK, and Zydus Pharmaceuticals in a Delaware federal court alleging that their planned generics of Sensipar infringed on its patent. 

Following a bench trial, the court ruled that Zydus’s generic infringed on Amgen’s patent, but that the planned generics from Amneal and Piramal did not. Amgen appealed that ruling, citing a key claim in the patent. 

A three-judge appeals court panel found that the judge misunderstood Amneal’s formulation of its generic and tossed out the previous ruling, clearing the way for Amgen to renew is patent challenge. However, the appeals court upheld the lower court’s decision with regard to Piramal and Zydus.

Sensipar earned almost $1.8 billion in 2018, but sales dropped sharply in 2019 to just $109 for the third quarter. Amgen attributed the sharp decline in sales to an increase in generic competition.