Contacts at Genome Therapeutics:
Christopher Taylor
Sr. Director, Investor Relations
(781) 398-2466
ctaylor@genomecorp.com

Sarah Emond
Media Relations Specialist
(781) 398-2544
semond@genomecorp.com

For Immediate Release

      Genome Therapeutics and Amgen Complete an Agreement to Discover and
                Commercialize New Therapeutics for Bone Diseases

Waltham, Mass. January 2, 2003 - Genome Therapeutics (Nasdaq: GENE) has
completed an agreement with Amgen Inc. for the identification and development of
novel therapeutic agents for bone diseases, including osteoporosis. Both
companies will participate in collaborative research efforts to discover one or
more drug candidates suitable for development. The companies may, as part of the
research activities, use genetic information, developed by Genome Therapeutics
based on research conducted at the Creighton University Osteoporosis Research
Center, which has been exclusively licensed to Amgen.

As part of the agreement, Genome Therapeutics will receive from Amgen an upfront
cash payment, sponsored research funding and, potentially, additional milestones
and other downstream consideration depending on the success of the discovery,
development and commercialization activities. The total potential additional
payments are significant and within the range commonly found in the industry in
agreements for research programs at this stage of development and consistent
with previous Genome Therapeutics discovery agreements focused on chronic human
diseases.

"The promise of the combined efforts of our two companies is supported by the
prior successes Amgen has had at bringing innovative human therapeutics to
market," said Steven M. Rauscher, CEO and President of Genome Therapeutics. "In
addition, this is the first agreement of this type in which Genome Therapeutics
participates in downstream discovery efforts and has other features which
represent an important step for Genome Therapeutics in building an integrated
biopharmaceutical company."

About Osteoporosis

Osteoporosis is a disease characterized by low bone mass, structural
deterioration of bone tissue and an increased susceptibility to fractures. If
not treated, the disease advances and the hip and spine become increasingly
vulnerable. According to the American Academy of Orthopaedic Surgeons,
osteoporosis affects over 25 million people in the United States at a direct
cost of $10 billion. It can result in 1.5 million fractures every year with one
out of two women and one in five men at risk of developing an
osteoporosis-related fracture in their lifetime.




                                         Genome Therapeutics and Amgen Agreement
                                                                 January 2, 2003
                                                                     Page 2 of 2


About Genome Therapeutics

Genome Therapeutics (www.genomecorp.com) is a biopharmaceutical company focused
on the discovery and development of pharmaceutical and diagnostics products. The
Company's most advanced product candidate, Ramoplanin, is in a Phase III
clinical trial for the prevention of bloodstream infections caused by
vancomycin-resistant enterococci (VRE). Genome Therapeutics' biopharmaceutical
business includes six major product discovery alliances with several
pharmaceutical companies including Schering-Plough, AstraZeneca, Wyeth and
bioMerieux. The Company's genomics services business, GenomeVision(TM) Services,
provides pharmaceutical and biotechnology companies, and government and academic
institutions with custom high-throughput sequencing, library construction,
integrated SNP services and the PathoGenome(TM) Database.

Forward-Looking Statement

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 trial
for Ramoplanin, and increased cost, due to the pace of enrollment of patients in
the trial 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, 2001 and those set forth in other filings that we may make with the
Securities and Exchange Commission from time to time.

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