CHADDS FORD, PA and DANBURY, CT--(Marketwire - December 17, 2007) - Endo Pharmaceuticals Holdings Inc. (NASDAQ: ENDP) and Penwest Pharmaceuticals Co. (NASDAQ: PPCO) announced today that on December 14, 2007, they received a notice from IMPAX Laboratories, Inc. advising of the FDA’s acceptance for substantive review, as of November 23, 2007, of IMPAX’s Abbreviated New Drug Application (ANDA) containing a new Paragraph IV certification under 21 U.S.C. § 355(j) for oxymorphone hydrochloride extended-release tablets CII. IMPAX stated in its letter that the FDA requested IMPAX to provide notification to Endo and Penwest of this certification. This Paragraph IV certification notice refers to Penwest’s U.S. Patent Nos. 7,276,250, 5,958,456 and 5,662,933, which cover the formulation of OPANA® ER. These patents are listed in the FDA’s Orange Book and expire in 2022, 2013 and 2013, respectively. In addition to these patents, OPANA ER has a new dosage form (NDA) exclusivity that prevents final approval of any ANDA by the FDA until the exclusivity expires on June 22, 2009.
