Genome Therapeutics Receives Patent for Genetic Sequences of Pseudomonas aeruginosa, Common Cause of Hospital Infections.

Business Editors/Health/Medical Writers

WALTHAM, Mass.--(BUSINESS WIRE)--May 7, 2003

Increases Intellectual Property Position in Anti-Infectives Research

The U.S. Patent and Trademark Office has issued patent No. 6,551,795 to Genome Therapeutics (Nasdaq: GENE) to cover the genetic sequences of Pseudomonas aeruginosa (P. aeruginosa). P. aeruginosa is a naturally occurring Gram-negative bacterium that causes serious infections in immunocompromised individuals, and is the fourth most common disease-causing pathogen in the hospital. The receipt of this patent strengthens the Company's intellectual property position, complements the Company's infectious diseases research program and validates our strategic approach to securing patent protection for medically-relevant pathogen sequences.

"Our research into novel treatments and diagnostics for diseases caused by serious pathogens is supported by our growing intellectual property portfolio," stated Richard Labaudiniere, Ph.D., Senior Vice President, Research & Development at Genome Therapeutics. "This patent underscores our leadership position in the understanding of the causes of many of the most common and virulent organisms affecting hospitalized patients."

Infections caused by P. aeruginosa often strike immunocompromised patients, including cystic fibrosis sufferers, burn victims and cancer patients, and can be resistant to standard antibiotic treatments. P. aeruginosa is a well-studied pathogen due to its ability to adapt to and thrive in varying environmental conditions. Most infections caused by P. aeruginosa occur in the hospital, where the bacterium is responsible for over 10 percent of all nosocomial infections. Often serious, P. aeruginosa infections are caused by two virulent protein toxins secreted by the bacterium, Exotoxin A and Exoenzyme S.

About Genome Therapeutics

Genome Therapeutics is a biopharmaceutical company focused on the discovery and development of pharmaceutical and diagnostics products. The Company's lead product candidate, Ramoplanin, is currently under Phase III investigation for the prevention of bloodstream infections caused by vancomycin-resistant enterococci (VRE), and under Phase II investigation for the treatment of Clostridium difficile-associated diarrhea (CDAD). Genome Therapeutics' biopharmaceutical business includes a robust internal drug discovery program in the area of anti-infectives, and seven major product discovery alliances with several pharmaceutical companies including Amgen, AstraZeneca, bioMerieux, Schering-Plough and Wyeth.

This news release may contain forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements represent our management's judgment regarding future events. Forward-looking statements typically are identified by use of terms such as "may," "will," "should," "plan," "expect," "intend," "anticipate," "estimate," and similar words, although some forward-looking statements are expressed differently. We do not plan to update these forward- looking statements. You should be aware that our actual results could differ materially from those contained in the forward- looking statements due to a number of risks affecting our business. These risk factors include risks related to our lead product candidate, Ramoplanin, such as (i) our inability to obtain regulatory approval to commercialize Ramoplanin due to negative, inconclusive or insufficient clinical data and (ii) delays in the progress of our clinical trials for Ramoplanin, and increased cost, due to the pace of enrollment of patients in the trials or fluctuations in the infection rate of enrolled patients. We are also subject to risks related to our inability or the inability of our alliance partners to (i) successfully develop products based on our genomics information, (ii) obtain the necessary regulatory approval for such products, (iii) effectively commercialize any products developed before our competitors are able to commercialize competing products or (iv) obtain and enforce intellectual property rights. In addition, we are subject to the risk factors set forth in Exhibit 99.1 to the Company's Annual Report on Form 10-K for the year ended December 31, 2002 and those set forth in other filings that we may make with the Securities and Exchange Commission from time to time.

Note: Genome Therapeutics will hold its Annual Meeting of Shareholders on Thursday May 8, 2003 at Ropes & Gray, One International Place, 100 Oliver Street, 36th Floor, Boston, MA at 10:00 AM.