Astellas Pharma Inc, a pharmaceutical company dedicated to improving the health of people around the world through the provision of innovative and reliable pharmaceuticals, confirmed that it has entered into a confidentiality agreement with OSI Pharmaceuticals, Inc.

Under the terms of the agreement, OSI will provide Astellas with access to certain non-public information. This follows Astellas’ approach to OSI after OSI’s announcement that its board of directors had instructed its management and financial advisors to contact interested third parties regarding a potential transaction.

Also, under the confidentiality agreement, until 11.59 p.m. EDT on May 15, 2010, Astellas will not acquire any shares pursuant to its outstanding tender offer, take any further action on the pending litigation initiated by it or file a preliminary or definitive proxy statement in connection with OSI’s annual meeting. This agreement will terminate, among other things if OSI enters into or announces its intent to enter into an agreement with respect to an acquisition of OSI.

There can be no assurance that an agreement with respect to an acquisition by Astellas for OSI will be reached.

Citigroup is acting as exclusive financial advisor to Astellas and Morrison & Foerster LLP is acting as legal counsel.