EXHIBIT 99.1
                                                                    ------------

ARIAD Initiates Phase 2 Clinical Trial of AP23573 in Patients with Relapsed
and/or Refractory Sarcomas

    CAMBRIDGE, Mass.--(BUSINESS WIRE)--Sept. 30, 2004--

    First global multicenter Phase 2 clinical trial of AP23573 in
solid tumors

    ARIAD Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced
initiation of enrollment of patients with bone and soft tissue
sarcomas in the first multicenter Phase 2 clinical trial of its novel
mTOR inhibitor, AP23573, as a single agent in solid tumors.
    This non-randomized study will evaluate the clinical benefit of
AP23573 in four well-defined groups of sarcoma patients, characterized
by tumor type. Up to approximately 175 patients will be enrolled in
the trial at approximately 15 centers in the United States and Europe.
AP23573 will be administered using a daily dosing regimen of drug.
    "In our nearly completed Phase 1 clinical trials reported today at
the EORTC international cancer symposium, all evaluable patients with
relapsed and/or refractory sarcoma had evidence of anti-tumor activity
- a promising result that supports our decision to further evaluate
AP23573 in this patient population in Phase 2," said Harvey J. Berger,
M.D., chairman and chief executive officer of ARIAD. "Despite
advancements in anti-cancer therapy, currently available treatment
options for such patients are extremely limited due the highly
resistant nature of this cancer. Sarcoma remains a disease with high
unmet medical need."
    The study will also include use of pharmacodynamic and
pharmacogenomic biomarkers, including functional imaging, to assess
the effects of AP23573 on the mTOR pathway and to help identify
patients who are likely to benefit most from treatment with AP23573.

    About Sarcoma

    Sarcomas are cancers of the connective tissue, including bones,
muscles, fat, cartilage, and joints. Sarcomas can arise anywhere in
the body and are divided into two main groups - bone tumors and soft
tissue sarcomas. They are further sub-classified based on the type of
cell found in the tumor. All sarcomas share certain pathologic
characteristics. There are approximately 10,000 new cases of sarcoma
diagnosed each year in the United States and close to 40,000 sarcoma
patients being treated in the United States and Europe. More
information about sarcomas is available on the web at
http://www.sarcoma.net/facts.htm and at
http://www.sarcomafoundation.com/master.html?Articleld=90.

    About AP23573

    The small-molecule drug, AP23573, starves cancer cells and shrinks
tumors by inhibiting the critical cell-signaling protein, mTOR, which
regulates the response of tumor cells to nutrients and growth factors,
and controls tumor blood supply and angiogenesis through effects on
Vascular Endothelial Growth Factor (VEGF).

    About ARIAD

    ARIAD is engaged in the discovery and development of breakthrough
medicines to treat cancer by regulating cell signaling with small
molecules. The Company is developing a comprehensive approach to
patients with cancer that addresses the greatest medical need -
aggressive and advanced-stage cancers for which current treatments are
inadequate. ARIAD also has an exclusive license to pioneering
technology and patents related to certain NF-(kappa)B treatment
methods, and the discovery and development of drugs to regulate
NF-(kappa)B cell-signaling activity, which may be useful in treating
certain diseases. Additional information about ARIAD can be found on
the web at http://www.ariad.com.

    Some of the matters discussed herein are "forward-looking
statements" within the meaning of the Private Securities Litigation
Reform Act of 1995. Such statements are identified by the use of words
such as "anticipate," "estimate," "expect," "project," "intend,"
"plan," "believe," and other words and terms of similar meaning in
connection with any discussion of future operating or financial
performance. Such statements are based on management's current
expectations and are subject to certain factors, risks and
uncertainties that may cause actual results, outcome of events, timing
and performance to differ materially from those expressed or implied
by such forward-looking statements. These risks include, but are not
limited to, risks and uncertainties regarding the Company's ability to
accurately estimate the actual research and development expenses and
other costs associated with the preclinical and clinical development
of our product candidates, the adequacy of our capital resources and
the availability of additional funding, risks and uncertainties
regarding the Company's ability to successfully conduct preclinical
and clinical studies of its product candidates, including those
clinical trials noted in this press release, risks and uncertainties
that clinical trial results at any phase of development may be adverse
or may not be predictive of future result or lead to regulatory
approval of any of the Company's product candidates, and risks and
uncertainties relating to regulatory oversight, intellectual property
claims, the timing, scope, cost and outcome of legal proceedings,
future capital needs, key employees, dependence on the Company's
collaborators and manufacturers, markets, economic conditions,
products, services, prices, reimbursement rates, competition and other
risks detailed in the Company's public filings with the Securities and
Exchange Commission, including ARIAD's Annual Report on Form 10-K for
the fiscal year ended December 31, 2003. The information contained in
this document is believed to be current as of the date of original
issue. The Company does not intend to update any of the
forward-looking statements after the date of this document to conform
these statements to actual results or to changes in the Company's
expectations, except as required by law.

    CONTACT: ARIAD Pharmaceuticals, Inc.
             Tom Pearson, 610-407-9260
             or
             Kelly Lindenboom, 617-621-2345