Generic drug maker Watson Pharmaceuticals Wednesday confirmed that Momenta Pharmaceuticals and Sandoz have filed suit against Amphastar Pharmaceuticals and Watson on September 21 in the US District Court for the District of Massachusetts. Watson and Amphastar intend to vigorously defend the claims in the lawsuit.

The suit alleges that Amphastar's Enoxaparin Sodium Injection product, which Watson has the exclusive right to distribute in the U.S. retail pharmacy channel, infringes Momenta's U.S. Patent Nos. 7,790,466 and 7,575,886. Enoxaparin Sodium Injection is a generic equivalent to Sanofi-Aventis' Lovenox.