Watson Pharmaceuticals, Inc, a leading specialty pharmaceutical company, announced that the United States District Court for the Southern District of Florida ruled that Watson's Naproxen Sodium ER tablets, the generic version of Naprelan, infringes Elan's US Patent No. 5,637,320 (320 Patent). The action, Elan Corporation Plc v. Andrx Pharmaceuticals, Inc, was initially brought by Elan in October 1998 following Andrx's filing of a paragraph IV Abbreviated New Drug Application for its product.

In March 2002, the District Court ruled that Elan's '320 Patent was invalid. Subsequently, in May 2004, the United States Court of Appeals for the Federal Circuit reversed the District Court's finding of invalidity and remanded the case for further proceedings.

In January 2005, Elan filed a related case against Andrx in the United States District Court for the Southern District of Florida alleging that Andrx's Naproxen Sodium ER tablets infringe the '320 Patent, and seeking damages for willful infringement. In late 2005 the parties completed briefing the District Court on the validity of the '320 Patent and whether Andrx's product infringes the '320 Patent. The matter has been under submission to the District Court since late 2005. In the ruling, the District Court held that Andrx's Naproxen Sodium ER tablets infringe the '320 Patent and that Andrx's infringement was willful. The District Court has set a further hearing on the matter for September 19, 2008, to address issues related to a damages phase of the trial and the possibility of injunctive relief. The Company intends to appeal the ruling.

"We are disappointed and disagree with the court's ruling and believe we have substantial meritorious issues to raise on appeal," stated Paul M Bisaro, Watson's president and chief executive officer. "We will continue to vigorously defend our position that our product does not infringe the '320 Patent'," concluded Bisaro. Andrx launched its 500 mg Naproxen Sodium ER tablets in September 2002. For the twelve months ended December 31, 2001, Elan's 500 mg Naprelan product had sales of approximately $27 million, according to IMS Health Data. For the twelve months ending June 30, 2008, Watson's 500 mg Naproxen Sodium ER tablets had sales of approximately $4 million, according to IMS Health Data.

Watson Pharmaceuticals, headquartered in Corona, CA, is a leading specialty pharmaceutical company that develops, manufactures, markets, sells and distributes brand and generic pharmaceutical products.