Teva Pharmaceuticals Industries Ltd. (TEVA) has filed its own lawsuit against a unit of Bayer AG (BAYRY), seeking court confirmation that the generic drug maker's patents on a birth-control drug are valid.

Teva, in a suit filed in U.S. District Court in Manhattan, said its commercial launch of Gianvi, a generic version of Bayer's birth-control drug Yaz, doesn't infringe any patent claim.

Bayer's pharmaceutical unit, Bayer Schering Pharma, had previously filed a lawsuit saying exactly that in Delaware on Tuesday, arguing any generic of Yaz should be stopped until 2014, when it believes it patent would expire.

Gianvi was approved by the U.S. Food and Drug Administration on March 30, 2009, and Teva said it has the right to launch the drug by July 2011. Teva, along with its subsidiary Barr Laboratories Inc., said it is seeking the court to affirm its patents and stop Bayer's lawsuit.

A representative for Bayer wasn't immediately available for comment.

Teva's release announcing the drug's launch on Friday said Yaz had $782 million in sales during 2009.

-By David Benoit, Dow Jones Newswires; 212-227-2017; david.benoit@dowjones.com