Bayer Schering Pharma AG, Germany and Bayer HealthCare Pharmaceuticals Inc. together with Schering Corporation have filed a patent infringement lawsuit in the US Federal Court in the District of Delaware against Teva Pharmaceuticals USA, Inc and Teva Pharmaceutical Industries, Ltd. The lawsuit concerns Teva's application to the FDA for approval to market a generic form of Levitra, Bayer Schering Pharma's therapy for the treatment of erectile dysfunction, prior to patent expiration.

The patent at issue in the suit is Bayer Schering Pharma's US Patent No. 6,362,178, expiring in 2018. In the US, Levitra is marketed by Schering-Plough and GlaxoSmithKline.