Pfizer Inc and its group companies filed a petition in a US court against Aurobindo Pharma and Dr Reddy’s Laboratories alleging that the Indian drug makers were planning separately to come out with generic versions of its blockbuster multi-billion dollar drug Ibrance (palbociclib) before the expiration of its patent.

Pfizer filed the possible patent infringement case against Aurobindo Pharma in the United States District Court for the District of Delaware and Dr Reddy’s in the New Jersey court.

Palbociclib is used to treat certain types of breast cancer. Ibrance clocked nearly $5 billion in revenues globally, including $3.25 billion in the US in 2019. In March 2019, several generic companies had filed abbreviated new drug applications with the USFDA to market generic versions of Ibrance.