Endo Pharmaceuticals said Monday it has settled its U.S. patent suit with Purdue Frederick over the pain drug OxyContin.

Purdue’s lawsuit had charged that Endo’s oxycodone extended-release tablets in 10 mg, 20 mg, 40 mg and 80 mg strengths infringed Purdue’s branded OxyContin product.

Under the settlement deal, Endo will continue selling its generic product until Dec. 31 of this year and will be released from all liability for infringement in connection with Endo’s prior and future sales of these products.

The deal is subject to approval by the U.S. Federal Trade Commission and the Antitrust Division of the Department of Justice.

Endo said it first launched its oxycodone extended-release drug on June 7, 2005, after a U.S. Court of Appeals for the Federal Circuit held Purdue’s patents were unenforceable, but that decision was later remanded back to New York District court for further consideration.

As a condition of the patent settlement, Purdue’s lawsuit and Endo’s counterclaims will be tossed out, Endo said.

“We are pleased to have reached a resolution of our dispute with Purdue that relieves us of the risk of patent infringement liability for selling our oxycodone extended-release products, and allows us to continue selling the products for a period of time,” said Caroline Manogue, Edno’s executive vice president and chief legal officer. “Further, with the lawsuit behind us, we can better focus on the current launch of Opana and Opana ER, Endo’s recently approved oxymorphone immediate- and extended-release products.”