Cubist Pharmaceuticals Licenses Rights to Novel Cephalosporin Antibiotic From Biochemie; IND Candidate Demonstrates Broad-Spectrum Coverage, Including MRSA.

Business Editors and Health/Medical Writers

BIOWIRE2K

LEXINGTON, Mass.--(BW HealthWire)--Aug. 1, 2002

Cubist Pharmaceuticals, Inc. (Nasdaq: CBST) today announced the acquisition of worldwide rights to CAB-175 from Biochemie GmbH, a unit of Novartis Generics business sector. CAB-175 is a unique investigational cephalosporin antibiotic in late-stage pre-clinical development and has demonstrated in vitro activity against most clinically relevant Gram-positive and Gram-negative bacteria, including important resistant species. Financial terms of the acquisition were not disclosed.

CAB-175 is a new chemical entity belonging to a sub-class of cephalosporins called azomethines. Although cephalosporins now represent roughly one-third of the estimated $23 billion global market for antibiotics, limitations to their use now exist due to the continued emergence of bacterial resistance. For example, currently marketed cephalosporins are not effective against methicillin-resistant Staphylococcus aureus (MRSA) strains, which are estimated to be the cause of approximately 35% of S. aureus infections in the U.S. and up to 42% and 70% of similar infections in parts of Europe and Asia, respectively. CAB-175 has demonstrated in vitro bactericidal (killing) activity against MRSA, and is also active against most other important Gram-positive bacteria, including susceptible and certain multi-drug resistant Pneumococci, Streptococci and Enterococci and virtually all clinically relevant Gram-negative bacteria, including many beta-lactamase-producing strains.

Preliminary pre-clinical animal studies indicate that CAB-175 could have a similar safety profile to ceftriaxone, a drug that has been successfully and safely prescribed for over 15 years in both adults and children. The compound is water soluble, with pharmacokinetics in non-human primates suggesting twice-daily parenteral dosing. Cubist will initially be investigating CAB-175 in an intravenous (IV) formulation, but will also perform feasibility studies on potential intramuscular (IM) and oral dosage formulations. In in vitro studies, CAB-175 has thus far demonstrated a very low potential for the development of bacterial resistance.

If successfully developed, CAB-175 could target hospitalized patient populations suffering from lower and upper respiratory infections, urinary tract infections, intra-abdominal infections, skin and soft tissue infections and febrile neutropenia. These indications represent in excess of 15 million treated patients each year on a global basis. CAB-175 complements well Cubist's current lead investigational antibiotic Cidecin(R) (daptomycin for injection), as commercialization efforts for CAB-175 and CIDECIN would target a similar physician audience, should they both ultimately gain regulatory approval.

"CAB-175 is an important addition to Cubist's growing antiinfective pipeline," said Scott M. Rocklage, Ph.D., Cubist's Chairman & CEO. "Following on Biochemie's thorough discovery efforts, we hope to make significant progress in our pre-clinical development of CAB-175, and anticipate filing an Investigational New Drug application (IND) during the first half of 2003 to begin formal human clinical trials."

Cubist Pharmaceuticals, Inc. is focused on becoming a global leader in the research, development and commercialization of novel pharmaceuticals to combat serious and life-threatening 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 has entered into agreements with Novartis Pharma AG 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) and EDGE(TM) are trademarks of Cubist Pharmaceuticals, Inc.

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