Cubist Pharmaceuticals Reports First Quarter 2002 Results; Company's 2001 Online Annual Report Now Available at www.cubist.com.

Business Editors and Health/Medical Writers

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

Cubist Pharmaceuticals, Inc. (Nasdaq: CBST) today reported the results for the first quarter ended March 31, 2002.

Total revenues for the first quarter ended March 31, 2002 were $2,320,000 as compared to $2,379,000 for the same period in 2001. Total operating expenses for the quarter ended March 31, 2002 were $20,348,000 as compared to $20,923,000 for the same period in 2001. Net loss for the quarter ended March 31, 2002 was $19,488,000, or ($0.69) per share, as compared to a net loss of $17,603,000, or ($0.63) per share, for the same period in 2001.

Although there was no significant change in operating expenses year over year, Selling, General and Administrative expenses increased as a percentage of total expenses, reflecting expanded headcount and an increase in pre-marketing expenses in preparation for the anticipated launch of the Company's investigational antibiotic Cidecin(R) (daptomycin for injection), should CIDECIN receive regulatory approval. The increase in interest expense in 2002 relative to 2001 is a result of a $165 million convertible debt offering completed in the fourth quarter of 2001.

The Company's cash and investment balance was $221,797,000 on March 31, 2002, and the Company had 28,495,451 shares outstanding.

"The biotech industry faced a number of challenges during the first quarter of 2002," said Scott M. Rocklage, Ph.D., Chairman and CEO of Cubist. "Cubist was no exception. Poor sector performance, combined with disappointing clinical results across the industry, has created uncertainty in the minds of many biotech investors. We have made several recent announcements that we believe clarify our development strategy and we have reaffirmed our commitment to achieve our forecasted operating timelines."

Dr. Rocklage continued, "Following the announcement of mixed results from the first of two CIDECIN Phase III community-acquired pneumonia studies (CAP1), we conducted extensive market research and conferred with the FDA to confirm our regulatory strategy of filing the NDA this year for the indication of complicated skin and soft tissue (cSST) infections. Based on positive feedback from both the marketplace and the FDA and the two successfully completed CIDECIN Phase III trials in cSST, in early March, we announced our decision to go forward with a 2002 CIDECIN NDA filing. We continue to operate on track to meet this goal.

"In the meantime, we are continuing to focus on generating CIDECIN data for supplemental regulatory indications and for scientific publication. Should CIDECIN receive U.S. regulatory approval, these data will become key components of our marketing strategy. We currently have ongoing a Phase III trial investigating the safety and efficacy of CIDECIN in the treatment of vancomycin-resistant Enterococcal (VRE) infections, and are poised to begin a Phase III trial evaluating CIDECIN in the treatment of endocarditis and bacteremia. We are continuing the analysis of the data generated from the CAP1 trial and will shortly be analyzing the data from the second CAP trial, with the expectation that these data will be useful in determining whether to investigate CIDECIN as a treatment of nosocomial (hospital-acquired) pneumonia.

"We continue to attempt to expand our product pipeline, through our clinical research on oral formulations of ceftriaxone (OCTX) and through both our lipopeptide and target-based drug discovery programs. In addition to anticipating a CIDECIN NDA filing by the end of 2002, we hope to have chosen a final OCTX formulation, expecting to begin clinical development during 2003, and we hope to advance multiple candidates from our drug discovery efforts into formal medicinal chemistry programs."

Dr. Rocklage concluded, "We expect these efforts to result in a steady flow of news events during 2002, a year we expect will be pivotal in our evolution towards becoming a fully integrated antiinfective biopharmaceutical company."

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 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.

                     CUBIST PHARMACEUTICALS, INC.
                       CONDENSED BALANCE SHEETS
                               UNAUDITED

                                           March 31,      December 31,
                                             2002            2001
ASSETS
Cash, cash equivalents and investments   $221,796,883     $243,134,679
Property and equipment, net                48,392,810       48,056,157
Other assets                               22,920,917       23,643,359

Total assets                             $293,110,610     $314,834,195

LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable                         $  3,150,034     $  7,336,002
Accrued expenses                           14,950,142       15,709,766
Deferred revenue                            8,500,079        9,900,080
Debt and capital lease obligations        212,549,045      212,387,769

Total liabilities                         239,149,300      245,333,617

Total stockholders' equity                 53,961,310       69,500,578

Total liabilities and stockholders'
  equity                                 $293,110,610     $314,834,195



                     CUBIST PHARMACEUTICALS, INC.
                  CONDENSED STATEMENTS OF OPERATIONS
                               UNAUDITED

                                          Three months ended
                                               March 31,
                                          2002            2001

Sponsored research revenues          $  2,319,728    $  2,379,365

Operating expenses:
 Research and development              12,773,429      16,413,576
 General and administrative             7,574,305       4,509,746

  Total operating expenses             20,347,734      20,923,322

Interest income                         1,477,302       2,378,840
Interest expense                       (3,255,091)     (1,103,062)
Other income (expense)                    317,927        (334,474)

Net loss                             ($19,487,868)   ($17,602,653)

Basic and diluted net loss per
  common share                       ($      0.69)   ($      0.63)

Weighted average number of common
  shares for basic and diluted net
  loss per common share                28,406,410      27,915,084

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