Cubist Pharmaceuticals Announces Positive Results From Phase II Cidecin Complicated Urinary Tract Infection Trial; Data to be Presented at ECCMID 2002 in Milan.

Business Editors and Health/Medical Writers

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LEXINGTON, Mass.--(BW HealthWire)--Feb. 14, 2002

Cubist Pharmaceuticals, Inc. (Nasdaq: CBST) today announced preliminary results from a Phase II feasibility trial investigating the safety and efficacy of its investigational antibiotic Cidecin(R) (daptomycin for injection) in the treatment of complicated urinary tract infection (cUTI) caused by Gram-positive bacteria. The trial achieved its goal of demonstrating no differences between the microbiologic and clinical cure rates for CIDECIN versus the comparator agent across all patient populations. In addition, there were no meaningful differences in the adverse event profiles of the two agents in this study.

This study involved 68 patients, half of whom received 4 mg/kg CIDECIN once daily and half of whom received Cipro(R) (ciprofloxacin) 400 mg twice daily, both via intravenous administration. The trial was a randomized, open-label, microbiologist- and evaluator-blinded, multi-center study conducted predominantly in Eastern Europe. The primary endpoint in this study was microbiologic efficacy in eradicating Gram-positive urinary tract pathogens in cases of cUTI in hospitalized patients. Clinical efficacy was a secondary endpoint of the study.

In the study, factors defining cUTI included urinary tract surgery within the prior three months, post-voiding residual volume, neurogenic bladder, renal, urethral or bladder calculi or urinary tract obstruction. In the microbiologically evaluable population, CIDECIN was 83% effective when evaluated microbiologically and 94% effective judged clinically. In the comparator arm, CIPRO achieved 85% microbiologic success and 93% clinical success. In addition, there were no observed clinical relapses in the CIDECIN arm (0/29), while 7% (2/28) of the patients relapsed in the comparator arm. Detailed data from this study are intended to be presented at the 12th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) taking place April 24-27, 2002 in Milan, Italy.

Scott M. Rocklage, Ph.D., Chairman and CEO of Cubist commented on the study: "We are very pleased with the results of this Phase II feasibility study, which is the first of its kind in the treatment of cUTIs caused by Gram-positive bacteria. While the results are promising, cUTI is not an indication planned for the core international regulatory filings of CIDECIN. It is our plan to publish these data in a peer-reviewed scientific journal."

Cubist Pharmaceuticals, Inc. is focused on becoming a global leader in the research, development and commercialization of novel antimicrobial drugs to combat serious and life-threatening bacterial and fungal infections. Cubist is evaluating the safety and efficacy of Cidecin(R) (daptomycin for injection) in the EDGE(TM) (Evaluation of Daptomycin against Gram-positive Entities) clinical trial program and has broadened its pipeline to include multiple pre-clinical drug candidates. The Company is engaged in strategic partnerships with Novartis Pharma AG and Merck & Co for the discovery and development of novel antiinfectives and with Gilead Sciences for the commercialization of daptomycin in Europe. Cubist is headquartered in Lexington, MA and has operations in Vancouver, BC, Canada and Slough, UK.

Cubist Safeharbor 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; and (iv) the Company's ability to develop and commercialize its products before its competitors. 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(R) (daptomycin for injection) and EDGE(TM) are trademarks of Cubist Pharmaceuticals, Inc. All other trademarks, servicemarks or trade names referred to in this release are the property of their respective owners.

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