TOKYO and MELVILLE, N.Y.May 16 /PRNewswire-FirstCall/ -- Astellas Pharma Inc. (TSE: 4503), a global pharmaceutical company, and OSI Pharmaceuticals, Inc. (Nasdaq: OSIP), a biotechnology company primarily focused on the discovery, development and commercialization of molecular targeted therapies addressing medical needs in oncology, diabetes and obesity, today announced that they have entered into a definitive merger agreement under which Astellas will acquire OSI. Under the terms of the merger agreement, Astellas will increase its offer price to $57.50 per share, which represents a premium of 55% to the closing price for OSI's shares of $37.02 on February 26, 2010, the last trading day before the announcement by Astellas of its tender offer. The boards of directors of both companies have unanimously approved the combination. The all-cash transaction is valued at $4.0 billion on a fully diluted basis. The combined company creates a world-class oncology platform supporting Astellas' stated growth strategy of becoming a Global Category Leader in Oncology, a high-priority therapeutic area for Astellas. OSI commercializes Tarceva® (erlotinib), a leading cancer medication. OSI's total annual revenues for 2009, as reported in its Form 10-K for the year ended December 31, 2009, were $428 million and operating income was $153 million. Masafumi Nogimori, President and Chief Executive Officer of Astellas, said, "The merger with OSI provides Astellas with a top-tier oncology platform in the U.S. and an expanded product portfolio and pipelines. In addition to Tarceva®, we are pleased to add its oncology infrastructure, discovery platform, expanded pipelines and talent base to our existing businesses. We look forward to working together with our OSI colleagues to grow the combined business and realize our shared goal of improving the health of the people around the world every day."