Watson sues Barr alleging patent infringement regarding Oxytrol

CORONA , Calif. Watson Pharmaceuticals announced Friday that it had filed a lawsuit against Barr Pharmaceuticals and subsidiary Barr Laboratories in the United States District Court of Delaware, alleging patent infringement.

The suit concerns an application that Barr filed with the Food and Drug Administration, requesting approval to market a generic version of Watson’s drug Oxytrol (oxybutynin transdermal system). Barr said the patents covering Oxytrol were invalid and unenforceable.

Watson filed the lawsuit under the Hatch-Waxman Act, which allows for the manufacture and marketing of generic drugs. Under the act, the FDA cannot approve Barr’s application unless a district court judge rules in favor of the company or two and a half years from Watson?s receipt of Barr?s notice letter.