Cubist Pharmaceuticals Introduces Lesson Plans for Science Teachers in Connection with New PBS Series.

LEXINGTON, Mass. -- Cubist Pharmaceuticals, Inc. (Nasdaq: CBST) today announced that, in connection with the premiere of an important new PBS series, Cubist has created a section on its web site to provide further education about how antibiotics are discovered from microorganisms found in soil. The new web page includes lesson plans that middle and upper school science teachers can use to involve their students in this exciting application of microbiology, chemistry, and pharmacology.

The need for new antibiotics is part of the story when PBS begins a six part series titled: Rx for Survival--A Global Health Challenge, which premieres November 1-3 on PBS. The series is a co-production of WGBH/NOVA Science Unit and Vulcan Productions. The second program in this series, called Rise of the Superbugs, describes the growing threat posed by "superbugs" -- strains of germs, such as tuberculosis and staph, that are resistant to our best antibiotics. This program, which features some of the Cubist scientists who are working on soil screening and other aspects of our natural product drug discovery process, airs as the second hour of the opening night of the series. Jeff Alder, PhD, and Vice President, Drug Discovery and Evaluation of Cubist, who is interviewed as part of the program, said, "The microbes in soil have been engaged in biological warfare for millions of years and have perfected the art of competing against each other through the production of natural antibiotics. We believe organisms from the soil provide a tremendous source of undiscovered molecules to combat the increasing resistance to the established drug classes."

The link to access the Lesson Plans is now available on the Cubist website. From the Cubist home page, www.cubist.com click on the New! Science Education link to access the Cubist drug discovery pages and educational documents.

To learn more about Rx for Survival, visit the special PBS Web site: http://www.pbs.org/rxforsurvival.

About Cubist

Cubist Pharmaceuticals, Inc. is a biopharmaceutical company focused on the research, development and commercialization of antiinfective products that address unmet medical needs in the acute care environment. In the U.S., Cubist markets CUBICIN(R) (daptomycin for injection), the first antibiotic in a new class of antiinfectives called lipopeptides. CUBICIN is currently the only once-daily bactericidal antibiotic approved in the U.S. with activity against both methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) in complicated skin and skin structure infections. The Company has announced that its Phase 3 Staphylococcus aureus (S. aureus) endocarditis and bacteremia trial of CUBICIN(R) (daptomycin for injection) at 6 mg/kg once daily met its primary endpoints of non-inferiority in the intent-to-treat (ITT) and per protocol (PP) populations. Cubist has filed a supplemental New Drug Application (sNDA) priority review for approval to add S. aureus endocarditis and bacteremia to the indication statement for CUBICIN. Cubist's pipeline includes HepeX-B(TM), a monoclonal antibody biologic being evaluated to determine its potential for the prevention of infection by the Hepatitis B virus (HBV) in liver transplant patients, and research efforts focused on novel members of the lipopeptide class of molecules and on natural products discovery. 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 expectations regarding our ability to continue to manufacture sufficient quantities of CUBICIN in accordance with current Good Manufacturing Practices; (iv) commercialization of products that are competitive with CUBICIN; (v) Cubist's ability to discover or in-license drug candidates; (vi) Cubist's ability to successfully develop drug candidates in its pipeline, including HepeX-B; (vii) Cubist's ability to successfully commercialize any product or technology developed by Cubist; (viii) Cubist's ability to establish and maintain successful manufacturing, sales and marketing, distribution, and development collaborations; (ix) legislative or regulatory changes adversely affecting Cubist or the biopharmaceutical industry; (x) Cubist's expectations regarding the future market demand and medical need for CUBICIN; (xi) Cubist's ability to protect its intellectual property and proprietary technologies; and (xii) 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. Cubist is providing this information as of the date of this news release and does not undertake any obligation to update any forward-looking statements contained in this document as a result of new information, future events or otherwise.

Cubist and CUBICIN are registered trademarks of Cubist Pharmaceuticals, Inc.; HepeX-B is a trademark of XTL Biopharmaceuticals Ltd.

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