Endo Pharmaceuticals Holdings Inc., a market leader in pain management, announced that the US District Court for the Southern District of New York has issued an Opinion and Order dismissing the claims that Endo's oxycodone extended-release tablets, 10mg, 20mg, 40mg, and 80mg, a bioequivalent version of Purdue Frederick's OxyContin, infringe Purdue's US Patent Nos. 5,549,912, 5,508,042 and 5,656,295, declaring the patents invalid, and enjoining Purdue from enforcing the patents. This ruling follows completion of a trial this past June.

The US Food and Drug Administration (FDA) will be informed immediately of the court's decision, and Endo is hopeful that its Abbreviated New Drug Application (ANDA) for its oxycodone extended-release tablets, which was filed under the Hatch-Waxman Act, will receive final FDA approval shortly. The FDA granted tentative approval of the company's ANDA for all four strengths of the product in July 2002. Endo also announced that it has not determined whether it will launch the product immediately or if it will wait until appellate review of the district court's decision, assuming the decision is appealed by Purdue.

In accordance with the Hatch-Waxman Act, Endo submitted a Paragraph IV certification of invalidity and non-infringement as to certain patents owned by Purdue Pharma on extended-release oxycodone, when the company filed and amended its ANDA for this product. Endo believes that it will have 180 days of marketing exclusivity with respect to the 10mg, 20mg and 40mg strengths of this product, since the company believes that it was the first applicant to file an ANDA containing a Paragraph IV certification for these oxycodone extended-release strengths. Given the recent passage of the Medicare Prescription Drug Improvement and Modernization Act of 2003, with accompanying amendments to the Hatch-Waxman Act, this marketing exclusivity would begin to run upon the earlier of Endo's commercial launch of these products or an appellate court decision affirming the district court's decision.

Endo's oxycodone extended-release tablets are AB-rated bioequivalent versions of the 10mg, 20mg, 40mg and 80mg strengths of OxyContin, a product of The Purdue Frederick Company that is indicated for the management of moderate-to-severe pain when a continuous, around-the-clock analgesic is needed for an extended period of time. These strengths had combined 2002 US branded sales of approximately $1.5 billion.