Astellas hopes this transaction will lead to the contribution to patients through addressing their unmet medical needs.About Cubist Cubist Pharmaceuticals, Inc. is a biopharmaceutical company focused on the research, development, and commercialization of pharmaceutical products that address significant unmet medical needs in the acute care environment. Cubist is headquartered in Lexington, Mass. Additional information can be found at Cubist’s web site at www.cubist.com. 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 pharmaceutical products. Astellas has approximately 17,000 employees worldwide. The organization is committed to becoming a global category leader in Urology, Immunology (including Transplantation) and Infectious Diseases, Oncology, Neuroscience and DM Complications and Kidney Diseases. For more information on Astellas Pharma Inc., please visit the company Website at www.astellas.com/en. Cubist Safe Harbor Statement This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. Any statements contained herein which do not describe historical facts, including but not limited to, statements regarding: (i) a five year extension of Hatch-Waxman exclusivity if ceftolozane/tazobactam is ultimately approved by the FDA and (ii) the development, regulatory filing and review, including the expected timing of our Phase 3 clinical trials in nosocomial pneumonia, clinical trial data readouts and NDA filing for ceftolozane/tazobactam in cUTI and cIAI, and commercial and therapeutic potential of ceftolozane/tazobactam, are forward-looking statements which involve risks and uncertainties that could cause actual results to differ materially from those discussed in such forward-looking statements. Such risks and uncertainties include, among others: clinical trials of ceftolozane/tazobactam may not be successful or initiated or conducted in a timely manner; we plan to rely, to a significant extent, on third party clinical research organizations, or CROs, to help us conduct clinical trials so the success and timing of these trials is dependent our ability to work with such CROs and their performance; technical difficulties or excessive costs relating to the manufacture or supply of ceftolozane/tazobactam; we plan to rely, to a significant extent, on third party contract manufacturers and suppliers to manufacture and supply ceftolozane/tazobactam on our behalf so our ability to obtain adequate supplies of ceftolozane/tazobactam is dependent on our ability to work with such third parties and on their performance; we may encounter other unanticipated or unexpected risks with respect to the development or manufacture of ceftolozane/tazobactam; our ability to successfully develop, gain marketing approval for and commercially launch ceftolozane/tazobactam for its planned indications and on the timelines that we expect and those additional factors discussed in our most recent annual report on Form 10-K filed with the Securities and Exchange Commission. We caution investors not to place considerable reliance on the forward-looking statements contained in this press release. These forward-looking statements speak only as of the date of this document, and we undertake no obligation to update or revise any of these statements.