Exhibit 99.1

         ARIAD Announces Major Advances in Development of its
               Lead Cancer Product Candidate, AP23573;

Reported at the American Society for Clinical Oncology Annual Meeting


    CAMBRIDGE, Mass.--(BUSINESS WIRE)--May 30, 2003--ARIAD
Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced, for the first
time, results of comprehensive in vivo studies of AP23573, its lead
cancer product candidate which is in Phase 1 clinical trials. AP23573
was highly effective in animal models of human solid tumors: treatment
initiated at an early stage of tumor growth induced persistent tumor
regression of up to 90%, and treatment at a later more-aggressive
stage still produced significant reductions in the rate of growth of
all six tumor types studied (i.e., brain, prostate, breast, pancreas,
lung, and colon cancers).
    The research also demonstrated that the anti-cancer activity of
three widely used chemotherapy drugs was markedly enhanced by combined
treatment with AP23573, supporting the use of AP23573 in multi-drug
regimens that can be tailored to treat specific cancers.
    The small-molecule, AP23573, was designed to have broad clinical
applications in solid tumors and other malignancies by inhibiting the
protein mTOR leading to shrinking of tumors by a novel mode of action
- cancer-cell starvation (metabolic arrest) through inhibition of
nutrient uptake to tumor cells, as well as inhibition of growth factor
stimulation. AP23573 can be administered orally or by injection.
    Molecular analysis of tumors removed from the animals dosed in the
studies reported today showed that mTOR signaling was completely
abolished one day after a single low dose of AP23573 and that this
suppression persisted for 2 to 3 days. These findings form the basis
for using biomarkers to determine patterns of responsiveness to
AP23573 therapy in clinical trials of patients with cancer.
    "We continue to build a strong scientific foundation for the
clinical use of AP23573, alone and in combination with other
anti-cancer drugs, in a broad spectrum of solid tumors and other
malignancies," said Harvey J. Berger, M.D., chairman and chief
executive officer of ARIAD.
    The abstract by Clackson, et al, "Broad anti-tumor activity of
AP23573, an mTOR inhibitor in clinical development," will be available
on the website of the American Society for Clinical Oncology
(http://www.asco.org/ac/1,1003,_12-002092,00.asp) on June 2, 2003.
    ARIAD is engaged in the discovery and development of breakthrough
medicines that regulate cell signaling with small molecules. The
Company is developing a comprehensive approach to the treatment of
cancer and is primarily focused on a series of product candidates for
targeted oncology indications. ARIAD also has an exclusive license to
pioneering technology and patents related to the discovery,
development and use of drugs that regulate NF-(kappa)B cell-signaling
activity, which has been implicated in many major 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
conduct preclinical and clinical studies of its product candidates and
the results of such studies, 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, 2002. 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
             Kathy Lawton, 617/621-2345


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