The US District Court for the District of Delaware has found both the patents in a suit brought against Mylan Pharmaceuticals are valid.
Genentech, OSI, (a US affiliate of Astellas), and Pfizer filed a patent infringement lawsuit against Mylan for infringement of patents, which cover Tarceva (erlotinib) tablets and their use, on 19 March 2009.
The lawsuit was based on an abbreviated new drug application filed by Mylan seeking permission to manufacture a generic version of Tarceva before the expiration of the US patents.