Teva Pharmaceutical Industries Ltd. said Tuesday it launched a generic version of Bayer's birth control pill Yaz, prompting a patent infringement lawsuit.
In April, Teva received Food and Drug Administration approval for its generic version of Yaz, marketed as Gianvi. Yaz, which is a low-dose version of Bayer's Yasmin oral contraceptive pill, had U.S. sales of $782 million in 2009.
The company previously said it planned to launch the drug on July 1, 2011, under terms of a licensing agreement between Bayer and Teva's Barr Pharmaceuticals subsidiary. But Teva said it could launch the drug earlier under certain conditions.
Bayer said in a statement that the earlier-than-expected launch "constitutes an act of infringement of the relevant intellectual property," in a statement. The company said it filed a lawsuit in Delaware.
Shares of Teva, based in Israel, fell 54 cents to $54.28 in afternoon trading.