Cubist Pharmaceuticals Appoints William J. Martone, MD, to Head Medical Affairs; Company Hires First Hospital Sales Representatives.

Business Editors/Health/Medical Writers

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LEXINGTON, Mass.--(BUSINESS WIRE)--Aug. 4, 2003

Cubist Pharmaceuticals, Inc. (Nasdaq: CBST) today announced the appointment of William J. Martone, MD, as Executive Director, Medical Affairs. The Company also announced that it has hired the first of three groups of hospital sales representatives intended to support the U.S. launch of Cubist's investigational antibiotic Cidecin(R) (daptomycin for injection), should it receive regulatory approval. The New Drug Application for CIDECIN is currently being reviewed by the U.S. Food & Drug Administration under priority review status, with a targeted action date of September 20, 2003.

Dr. Martone comes to Cubist with over 25 years of infectious disease experience to establish and lead Cubist's Medical Affairs Department. In addition to the role of liaison between the medical community and Cubist, the Medical Affairs Department will also be responsible for pharmacovigilence, drug information, and Phase 3b, Phase 4 and pharmacoeconomic studies. Most recently, Dr. Martone was Senior Executive Director of the National Foundation for Infectious Diseases (NFID), a position held since 1995. Prior to that, he had a distinguished career at the Centers for Disease Control (CDC) where he served as the Chief of the Epidemiology Branch of the Hospital Infections Program at the CDC's National Center for Infectious Diseases, ultimately becoming Director of the program. He has served as Clinical Associate Professor of Medicine at Emory University School of Medicine and as Attending Physician, Division of Infectious Diseases at the Washington DC Veterans Administration Medical Center.

Cubist also today announced the completion of a key component of its supply chain for CIDECIN. Cubist recently entered into an agreement with Integrated Commercialization Solutions, Inc. (ICS), a subsidiary of AmerisourceBergen Corporation, to warehouse and distribute CIDECIN, should it receive U.S. regulatory approval.

Michael W. Bonney, Cubist's President & CEO, commented on today's news: "We could not be more pleased with the addition of Bill to our team, as Medical Affairs will play a key role in the successful launch of CIDECIN, if approved. We are also excited about our growing sales organization. Our sales managers have been able to be highly selective in their screening process, and the resultant hires thus far average 11 years of hospital-based sales experience focusing on our top targeted institutions. As we prepare for an expected early November launch of CIDECIN," Mr. Bonney concluded, "we feel our ability to manage the launch properly, both monitoring inventory levels and ensuring efficient distribution, should be greatly enhanced by our relationship with ICS."

About Cubist

Cubist Pharmaceuticals, Inc. is a biopharmaceutical company focused on the research, development and commercialization of antiinfective drugs. Cubist has submitted a New Drug Application (NDA) to the U.S. Food & Drug Administration (FDA) for Cidecin(R) (daptomycin for injection) for the treatment of complicated skin and skin structure infections. The NDA for CIDECIN is currently being reviewed by the FDA under priority review status. Cubist's pipeline includes CAB-175, a next-generation parenteral cephalosporin antibiotic in Phase 1 trials, and an oral version of ceftriaxone (OCTX), a broad-spectrum cephalosporin antibiotic in pre-clinical development. Cubist is headquartered in Lexington, MA.

Cubist Safe Harbor Statement

Statements contained herein that are not historical fact may be forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, that are subject to a variety of risks and uncertainties. There are a number of important factors that could cause actual results to differ materially from those projected or suggested in any forward-looking statements made by the Company. These factors include, but are not limited to: (i) the Company's ability to successfully complete product research and development, including pre-clinical and clinical studies and commercialization; (ii) the Company's ability to obtain required governmental approvals; (iii) the Company's ability to attract and/or maintain manufacturing, sales, distribution and marketing partners; (iv) the Company's ability to develop and commercialize its products before its competitors; and (v) the Company's ability to finance its operations. Additional factors that would cause actual results to differ materially from those projected or suggested in any forward-looking statements are contained in the Company's filings with the Securities and Exchange Commission, including those factors discussed under the caption "Risk Factors" in the Company's recent SEC filings.

Cidecin is a registered trademark of Cubist Pharmaceuticals, Inc.

Additional information can be found at the Company's web site at www.cubist.com