TOKYO, June 9 /PRNewswire/ -- Astellas Pharma Inc. (TSE: 4503) announced today that the company has completed its acquisition of OSI Pharmaceuticals, Inc. (Nasdaq: OSIP) for $4.0 billion. Masafumi Nogimori, President and CEO of Astellas said, "We are delighted to announce the completion of this transaction with OSI. We are truly excited by the opportunities that the combination will provide and we look forward to working with our new colleagues at OSI. This compelling transaction marks an important step forward for Astellas as the company works towards developing a world-class oncology platform and realizing our goal of improving the health of people around the world." OSI is a biotechnology company primarily focused on the discovery, development and commercialization of molecular targeted therapies addressing medical needs in oncology, diabetes and obesity. OSI manufactures and sells Tarceva® (erlotinib), a leading cancer medication, and has several prospective new oncology medications in its R&D pipeline. OSI is expected to augment Astellas' strong existing franchises in urology and transplantation, expanding the product portfolio and pipeline of the combined company. Astellas completed the acquisition of OSI through a short-form merger without a meeting of OSI's stockholders. In the merger, each outstanding share of OSI common stock not purchased in Astellas' tender offer or otherwise owned by Astellas was converted into the right to receive the same $57.50 consideration that was provided in the tender offer, without interest, except shares for which appraisal rights are validly asserted. OSI is now a wholly-owned subsidiary of Astellas US Holding, Inc., a holding company owned by Astellas Pharma Inc., and OSI's common stock has ceased to be traded on the Nasdaq Global Select Market. Citigroup is acting as exclusive financial advisor to Astellas and Morrison & Foerster LLP is acting as legal counsel.