Endo Pharmaceuticals has settled long-running patent infringement litigation with Purdue Frederick over three U.S. Patents, namely, 5,656,295 (the ‘295 patent); 5,508,042 (the ‘042 patent); and 5,266,331 (the ‘331 patent) listed with O.B. for oxycodone extended-release tablets, marketed as OxyContin. Under the settlement deal, Endo will continue to market its generic product until December 31, 2006 and will be released from all liability for infringement in connection with Endo’s prior and future sales of generic oxycodone extended-release tablets. However, the deal is subject to approval by the U.S. Federal Trade Commission and the Antitrust Division of the Department of Justice. Endo launched its generic oxycodone extended-release tablets on June 07, 2005 after the U.S. Court of Appeals for the Federal Circuit affirmed the U.S. District Court for the Southern District of New York ruling that Purdue’s patents were unenforceable due to inequitable conduct before the USPTO and sent the case back to the District Court for further considerations. Following CAFC ruling, Purdue filed a petition for rehearing which was granted on February 01, 2006 withdrawing its earlier decision. In its revised decision, the CAFC vacated the inequitable conduct judgment and sent the case back to the District Court for further proceedings in accordance with its revised opinion. The CAFC also affirmed the District Court ruling that Endo proposed product would infringe Purdue’s patents. After almost 6 years of legal tussle, Endo and Purdue finally zeroed down to patent settlement leaving behind the trace of unsettled patent dispute, particularly the critical balance of materiality and intent in determining inequitable conduct.