Watson confirms PDE-5 inhibitor patent challenge

Watson Pharmaceuticals, Inc. recently confirmed that its subsidiary, Watson Laboratories, Inc., filed an abbreviated new drug application (ANDA) with the FDA seeking approval to market sildenafil citrate tablets in 25-, 50-, and 100-mg doses.

The tablets are a generic version of Pfizer Inc.’s Viagra, which is indicated for treatment of erectile dysfunction.

Watson said Pfizer filed suit against Watson on June 1, 2011, in the U.S. District Court for the Southern District of New York seeking to prevent Watson from commercializing its product prior to the expiration of a key patent. Pfizer’s lawsuit was filed under the provisions of the Hatch-Waxman Act, resulting in a stay of final FDA approval of Watson’s ANDA until Nov. 6, 2013 or until final resolution of the matter before the court, whichever occurs sooner.