The pharmaceutical company Esperion has retained Gibson, Dunn & Crutcher in a federal lawsuit seeking $300 million from a European pharmaceutical company, claiming that the company failed to fulfill its contractual obligations in connection with a cholesterol medication.

Esperion sued the defendant, Daiichi Sankyo Europe, in Manhattan federal court on March 27 and filed an amended complaint on Thursday, the same day a Gibson Dunn team led by partner Orin Snyder entered appearances in the suit.