Astellas Pharma Inc.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, 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."

Colin Goddard, Ph.D., Chief Executive Officer of OSI Pharmaceuticals, said, "We believe today's announcement recognizes the significant value we have built for our stockholders while providing the merged companies the opportunity to forge a stronger collective path forward in a shared mission to provide innovative new medicines to patients around the world."

About Astellas
Astellas Pharma Inc., located in Tokyo, Japan, is a pharmaceutical company dedicated to improving the health of people around the world through the provision of innovative and reliable pharmaceuticals. Astellas has approximately 15,000 employees worldwide. The organization is committed to becoming a global category leader in urology, immunology & infectious diseases, neuroscience, DM complications & metabolic diseases and oncology. For more information on Astellas Pharma Inc., please visit our website at http://www.astellas.com/en.

About OSI Pharmaceuticals
OSI Pharmaceuticals, Inc. is committed to "shaping medicine and changing lives" by discovering, developing and commercializing high-quality, novel and differentiated targeted medicines designed to extend life and improve the quality of life for patients with cancer and diabetes/obesity. For additional information about OSI, please visit http://www.osip.com.