FDA-Approved Fluoroquinolone Being Readied for Launch in U.S.

WALTHAM, Mass.--(BUSINESS WIRE)--March 11, 2004--Genome Therapeutics Corp. (Nasdaq: GENE - News) has received marketing approval for FACTIVE® (gemifloxacin mesylate) tablets for the treatment of acute bacterial exacerbations of chronic bronchitis from the Therapeutic Products Directorate of Health Canada. Already approved by the U.S. Food and Drug Administration, FACTIVE tablets are expected to launch in the U.S. this summer.

"The approval of FACTIVE tablets by Health Canada represents a key milestone for the drug as Canada becomes the second country in our licensed territories to approve FACTIVE tablets for treating acute bacterial exacerbations of chronic bronchitis," stated Gary Patou, M.D., Executive Vice President and Chief Medical Officer of Genome Therapeutics. "The additional regulatory approval FACTIVE tablets have received underscores our commitment to building a global brand for the drug."

The Company is currently developing its commercialization strategy for Canada.

Complete prescribing information for the drug's approved use in Canada, including important information about adverse reactions, drug interactions, contraindications, warnings, precautions and dosage and administration, is available from the Company upon request. FACTIVE tablets are approved in Canada for treating acute bacterial exacerbations of chronic bronchitis caused by Streptococcus pneumonia, Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis and Staphylococcus aureus.

About FACTIVE® Tablets in the U.S.

FACTIVE tablets are orally administered, broad-spectrum fluoroquinolone antibiotics to which Genome Therapeutics has licensed all North American and European rights for commercialization. FACTIVE tablets are approved in the U.S. for the treatment of community-acquired pneumonia of mild to moderate severity(1) and for treating acute bacterial exacerbations of chronic bronchitis(2). FACTIVE tablets should only be used to treat infections that are proven or strongly suspected to be caused by bacteria. It does not treat viral infections. The most common side effects include diarrhea, rash, nausea, headache, vomiting, stomach pain, dizziness, and taste perversion. Serious and occasionally fatal hypersensitivity and/or anaphylactic reactions have been reported in patients receiving fluoroquinolone therapy. FACTIVE tablets should be discontinued immediately at the appearance of any sign of a hypersensitivity reaction and the need for fluoroquinolone therapy should be evaluated. FACTIVE tablets should also be discontinued if a patient experiences pain, inflammation, or rupture of a tendon. As with other fluoroquinolones, FACTIVE tablets should be used with caution in patients with CNS diseases and those who present with diarrhea, and should be discontinued if a patient experiences central nervous system reactions.

The safety and effectiveness of FACTIVE tablets in children, adolescents, pregnant women, and lactating women have not been established. Gemifloxacin may prolong the QT interval in some patients and should be avoided in patients with a history of prolongation of the QTc interval, patients with uncorrected electrolyte disorders, and patients receiving class 1A or class III antiarrhythmic agents. Patients should not take antacids containing magnesium and/or aluminum or products containing ferrous sulfate (iron), multivitamin preparations containing zinc or other metal cations, or Videx® (didaosine) chewable/buffered tablets or the pediatric powder for oral solution within 3 hours before or 2 hours after taking FACTIVE tablets. FACTIVE tablets should be taken at least 2 hours before sucralfate. As with all drugs in the class, patients should avoid excessive sunlight or artificial ultraviolet light while taking FACTIVE tablets, and should discontinue treatment if a photosensitivity reaction is suspected. Patients receiving FACTIVE tablets should also maintain adequate hydration. For complete prescribing information, please see the package insert available at www.factive.com.

(1) Caused by Streptococcus pneumoniae (including multi-drug resistant strains), Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, Chlamydia pneumoniae or Klebsiella pneumoniae. (2) Caused by Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae or Moraxella catarrhalis. About Genome Therapeutics

Genome Therapeutics, which recently merged with Genesoft Pharmaceuticals, is a biopharmaceutical company committed to the clinical development and commercialization of important new therapeutics to address unmet medical needs. The Company is currently focusing on anti-infectives and is preparing for a launch in the summer of 2004 of its lead product, FACTIVE® (gemifloxacin mesylate) tablets, recently approved by the FDA.

In addition, the Company also has a novel antibiotic candidate, Ramoplanin, in a Phase II trial for the treatment of Clostridium difficile-associated diarrhea and in Phase III development for the prevention of vancomycin-resistant enterococci bloodstream infections. The Company's preclinical programs include an oral peptide deformylase inhibitor series for the potential treatment of respiratory tract infections as well as development of a FACTIVE® intravenous formulation. For more information, please visit www.genomecorp.com.

Forward-Looking Statement for Genome Therapeutics

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 factors include the risk that the businesses of Genome Therapeutics and Genesoft Pharmaceuticals will not be integrated successfully and the significant costs related to the integration. In addition, our business is significantly dependent upon our ability to launch the commercial sale of FACTIVE® tablets, and, due to the limitations on our resources and experience in commercializing products, there can be no assurance that we will be able to successfully launch FACTIVE tablets. Even if we succeed in launching FACTIVE tablets, the product may not gain market acceptance due to competition from competing products or unanticipated safety, efficacy, manufacturing or other regulatory issues. It is also uncertain whether we will be able to expand the indications for which FACTIVE tablets are approved as a result of, for example, failures in future clinical trials or safety concerns. We continue to be subject to the 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 successfully develop and commercialize products based on our discoveries. 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 ending December 31, 2003 and those set forth in other filings that we may make with the Securities and Exchange Commission from time to time.

Contact:

Genome Therapeutics Investor Contact: Christopher Taylor, 781-398-2466 or

Media Contact: Sarah Emond, 781-398-2544

Source: Genome Therapeutics