Impax said that the FDA has requested the company to provide notification to Endo and Penwest of this certification. This paragraph IV certification notice refers to Penwest’s patents which cover the formulation of Opana ER. In addition to these patents, Opana ER has a new dosage form (NDA) exclusivity that prevents final approval of any abbreviated new drug application (ANDA) by the FDA until the exclusivity expires on June 22, 2009.
Endo and Penwest are currently reviewing the details of this new notice from Impax and will continue to pursue all available legal and regulatory avenues in defense of Opana ER, including enforcement of their intellectual property rights and approved labeling.