MELVILLE, N.Y.--(BUSINESS WIRE)--OSI Pharmaceuticals, Inc. (NASDAQ: OSIP) announced that the Company received notification from the U.S. Patent and Trademark Office (PTO) that an initial office action has been issued regarding OSI’s application for a reissue of the Company’s composition of matter patent for Tarceva® (erlotinib), U.S. Patent No. 5,747,498 (the ‘498 patent). The office action includes an indication of allowability to composition of matter claims, including a claim specifically directed to Tarceva, while initially rejecting certain other claims. A rejection of some claims in an initial office action is not unusual in a patent reissue application proceeding.