Genome Therapeutics' Lead Clinical Candidate, Ramoplanin, Part of Program at the 43rd Interscience Conference on Antimicrobial Agents and Chemotherapy.

Business Editors/Health/Medical Writers

WALTHAM, Mass.--(BUSINESS WIRE)--Sept. 9, 2003

-- Novel antibiotic the subject of seven presentations during

next week's ICAAC --

Researchers from Genome Therapeutics (Nasdaq: GENE) and other leading medical, biotechnology and academic institutions will present new research on the Company's product candidate, Ramoplanin, at next week's Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC). Being held September 14-17, 2003 in Chicago, Illinois, the 43rd ICAAC will attract more than 12,000 scientists and medical professionals from around the world to discuss the latest developments in the field of infectious diseases and antimicrobial agents.

"The breadth of data being presented at this year's ICAAC covering the in vitro and in vivo activity of Ramoplanin emphasizes the increasing level of interest in the academic and medical communities about the potential of this novel antibiotic to prevent and treat serious infections and control the spread of nosocomial pathogens," stated Steven M. Rauscher, Chairman and CEO of Genome Therapeutics.

The current program features the following Ramoplanin-related sessions. Copies of the presentations will be available at www.genomecorp.com next week.

September 14th:

F-541 (poster): "Activities of Cell Wall Inhibitors Towards Vancomycin-Resistant Staphylococcus aureus (VRSA) Isolated at the Hershey Medical Center," B. Bozdogan, Hershey Medical Center

B-328 (poster): "Superior Efficacy of Short Treatment Duration of Ramoplanin over Vancomycin in the Hamster Model of C. difficile Associated Colitis," D. Jabes, Vicuron Pharmaceuticals

September 15th:

C1-1119 (oral presentation): "Ramoplanin is Effective against Staphylococcus Biofilms," T. Opperman, Genome Therapeutics

September 16th:

C1-1630 (poster): "In vitro Activity of Ramoplanin and Comparator Agents against Recent Clinical Isolates of Enterococci," R. Blosser, Focus Technologies

C1-1807 (poster): "Over-expression of murG in S. aureus does not Alter the Ramoplanin MIC," L. Ling, Genome Therapeutics

September 17th:

E-2188 (poster): "In Vitro Activity of Ramoplanin against Clostridium difficile, Including Strains with Reduced Susceptibility to Vancomycin or with Resistance to Metronidazole," T. Pelaez, Hospital Gregorio Maranon (Spain)

E-2190 (poster): "Surveillance for Resistance to Metronidazole, Vancomycin or Ramoplanin in Genotypically Distinct and Clonal Clostridium difficile Strains," M. Wilcox, University of Leeds (UK)

About Ramoplanin

Genome Therapeutics' lead product candidate, Ramoplanin, is an investigational new drug in clinical development for the prevention, treatment and control of serious hospital-based infections. Licensed from Vicuron Pharmaceuticals, Ramoplanin, which has Fast Track status from the FDA, is currently in a Phase III clinical trial for the prevention of VRE bloodstream infections and in a Phase II study for treating Clostridium difficile-associated diarrhea (CDAD). Existing preclinical data suggest Ramoplanin may have potential in controlling several antibiotic-resistant, Gram-positive bacteria such as vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus and vancomycin-resistant Staphylococcus aureus. The antibiotic has also been shown to be bactericidal in vitro against Clostridium difficile. In a Phase II study, Ramoplanin was shown to be highly effective at decolonizing patients carrying VRE in their gastrointestinal (GI) tracts. A pilot study is also underway examining Ramoplanin's potential role in controlling the spread of nosocomial bacteria.

About Genome Therapeutics

Genome Therapeutics is a biopharmaceutical company focused on the discovery and development of pharmaceutical products for specialty markets. The Company's lead product candidate, Ramoplanin, is in development for the prevention, treatment and control of serious hospital-based infections. Ramoplanin is currently in a Phase III clinical trial for the prevention of bloodstream infections caused by vancomycin-resistant enterococci (VRE), and in a Phase II clinical trial for the treatment of Clostridium difficile-associated diarrhea (CDAD). Genome Therapeutics' biopharmaceutical portfolio also includes seven major product discovery and development alliances with 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.