Cubist Pharmaceuticals Begins Shipping Cubicin to U.S. Institutions.

Health/Medical Writers

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

Cubist Pharmaceuticals, Inc. (Nasdaq: CBST) today announced that it has begun shipping its flagship antibiotic product, Cubicin(TM) (daptomycin for injection), to U.S. hospitals. Cubist received U.S. Food & Drug Administration marketing approval for CUBICIN on September 12, 2003.

CUBICIN is indicated for the treatment of complicated skin and skin structure infections (cSSSI) caused by Gram-positive bacteria, including those caused by MRSA (methicillin-resistant Staphylococcus aureus) and MSSA (methicillin-susceptible S. aureus). CUBICIN is currently the only once-daily rapidly bactericidal antibiotic proven effective against both MRSA and MSSA.

Michael Bonney, President and CEO of Cubist commented on the launch: "Today marks another important milestone at Cubist, as we have begun filling the first commercial orders for CUBICIN. Since our September approval, we have finished hiring and training our CUBICIN national sales team and we believe our team is well prepared to effectively and efficiently introduce CUBICIN to the infectious disease community at key institutions across the country. To date, we have been pleased with the level of interest in the product and the number of hospital formularies onto which CUBICIN has been placed."

CUBICIN is an antibacterial agent from a new class of antibiotics called cyclic lipopeptides, and has clinical utility in the treatment of infections caused by aerobic Gram-positive bacteria. The in vitro spectrum of activity of CUBICIN encompasses most clinically relevant Gram-positive pathogenic bacteria, including bacterial isolates resistant to methicillin, vancomycin and linezolid. In the U.S., MRSA now accounts for nearly 60% of staphylococcal infections in hospitals, and the incidence of MRSA in the community is on the rise as well.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of CUBICIN and other antibacterial drugs, CUBICIN should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria. Patients receiving CUBICIN should be observed for the development of muscle pain or weakness and have creatine phosphokinase (CPK) levels monitored weekly. CUBICIN is not indicated for the treatment of pneumonia. The most commonly reported adverse events in the cSSSI clinical trials in adults were constipation, nausea and headache.

CUBICIN is indicated for the treatment of complicated skin and skin structure infections caused by susceptible strains of the following Gram-positive microorganisms: Staphylococcus aureus (including methicillin-resistant strains), Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus dysgalactiae subsp. equisimilis and Enterococcus faecalis (vancomycin-susceptible strains only).

For full prescribing information, visit www.Cubicin.com.

About Cubist

Cubist Pharmaceuticals, Inc. is a biopharmaceutical company focused on the research, development and commercialization of antiinfective drugs. Cubist recently received approval from the U.S. Food & Drug Administration to market Cubicin(TM) (daptomycin for injection), for the treatment of complicated skin and skin structure infections caused by Gram-positive bacteria. 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, and such statements 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 Cubist. These factors include, but are not limited to: (i) the level of acceptance of CUBICIN by physicians, patients, third-party payors, and the medical community generally; (ii) Cubist's ability to continue to develop, secure additional regulatory approvals for, and successfully market, CUBICIN; (iii) Cubist's ability to manufacture CUBICIN on a commercial scale; (iv) commercialization of products that are competitive with CUBICIN; (v) Cubist's ability to further identify, develop, and achieve commercial success for new products and technologies; (vi) Cubist's ability to establish and maintain successful manufacturing, sales and marketing, distribution, and development collaborations; (vii) legislative or regulatory changes adversely affecting Cubist or the biopharmaceutical industry; (viii) Cubist's ability to protect its intellectual property and proprietary technologies; (ix) Cubist's ability to finance its operations. Additional factors that could cause actual results to differ materially from those projected or suggested in any forward-looking statements are contained in Cubist's recent filings with the Securities and Exchange Commission, including those factors discussed under the caption "Risk Factors" in such filings.

Cubicin is a trademark of Cubist Pharmaceuticals, Inc.

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