In the complaints filed in the federal court in Delaware, Sanofi has argued that these generic drug manufacturers would infringe two US patents granted for its $140-million prostrate drug, Uroxatral, if the companies are allowed by the US Food and Drug Administration (FDA) to market the copycat versions in the US. Other firms that have been also sued are Teva, Barr Labs, Actavis, Mylan Pharma and Par Pharma.

A Sun Pharma spokesperson said, “As a matter of practice, we generally do not talk about specific product filings.”

Others refused to comment. Indian firms are keen on generics with a first-to-file strategy by filing the paragraph IV abbreviated new drug application (ANDA) with the US FDA.

Says, DG Shah, secretary general, Indian Pharmaceuticals Alliance, “The first-to-file has a major advantage in the US market where price erosion is very rapid. It offers the reward of a 180-day exclusivity. The pathway for generic is designed to incentives early entry of generics. The risk and reward go together.”

Sun was sued early this month by US-based Sepracor for alleged infringement patent granted to Sepracor’s Clarinex, used to treat allergies, following Sun’s submission of a paragraph IV ANDA.