EXHIBIT 99.1

 ARIAD Receives Fast-Track Designation by the FDA for mTOR Inhibitor,
                 AP23573, in the Treatment of Sarcoma;
  Addresses Limited Treatment Options for Life-threatening Conditions

    CAMBRIDGE, Mass.--(BUSINESS WIRE)--April 20, 2005--ARIAD
Pharmaceuticals, Inc. (Nasdaq:ARIA) today announced that its novel
mTOR inhibitor, AP23573, has been designated a fast-track product by
the U.S. Food and Drug Administration (FDA) for the treatment of soft
tissue and bone sarcomas. The FDA's decision was based, in part, on
review of both Phase 1 and Phase 2 clinical trials of AP23573
conducted by ARIAD in refractory sarcoma patients and the recognition
that soft tissue and bone sarcomas are serious and life-threatening
conditions for which treatment options are limited or non-existent.
The FDA's fast-track program is designed to facilitate the development
and expedite the review of new drugs that have the potential to
address unmet medical needs. Based on today's announcement, ARIAD will
pursue treatment of soft tissue and bone sarcomas as the initial
registration path for AP23573.
    The benefits of the FDA's fast-track program include closer and
more frequent interactions with the agency during clinical-trial
planning and New Drug Application (NDA) filing and generally a higher
likelihood of being granted accelerated approval on the basis of a
surrogate measure of clinical benefit in cancer patients, such as
progression-free survival.
    "We believe that the FDA's fast-track designation for AP23573 is
the Company's most important milestone to date," said Harvey J.
Berger, M.D., chairman and chief executive officer of ARIAD. "Since
there are no effective therapies currently available for advanced
soft-tissue sarcomas or metastatic refractory sarcomas in general, the
FDA decision represents a potential breakthrough for patients with an
otherwise untreatable cancer."
    Initial data from the ongoing Phase 2 study of AP23573 in patients
with relapsed and/or refractory sarcoma will be presented at the
American Society of Clinical Oncology annual meeting being held in
Orlando, Florida, May 13 to 17, 2005.

    About Sarcoma

    Sarcomas are cancers of the connective tissue, including bones,
muscles, fat, cartilage, and joints, not discriminating by age, gender
or race. 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 or tissue from which
the tumor developed. There are approximately 12,000 new cases of
sarcoma diagnosed each year in the United States and approximately
100,000 sarcoma patients overall in the United States. More
information about sarcomas is available at
http://www.sarcomafoundation.com and at
http://www.sarcoma.net/facts.htm.

    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) in tumor and endothelial
cells. AP23573 also blocks the proliferation and migration of vascular
smooth muscle cells, the primary cause of narrowing and reblockage of
injured arteries, and is an analog of sirolimus, another mTOR
inhibitor that has been approved for use in drug-eluting stents.
AP23573 is currently in Phase 1 and 2 clinical trials in patients with
solid tumors and hematologic cancers. AP23573 has been designated a
fast-track product by the U.S. Food and Drug Administration for the
treatment of soft tissue and bone sarcomas.

    About ARIAD

    ARIAD is engaged in the discovery and development of breakthrough
medicines to treat disease 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. Medinol Ltd. also is developing stents and other medical
devices that deliver ARIAD's lead cancer product candidate to prevent
reblockage at sites of vascular injury following stent-assisted
angioplasty. ARIAD 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 timing and actual research and development
expenses and other costs associated with the preclinical and clinical
development and manufacture of our product candidates, the adequacy of
our capital resources and the availability of additional funding,
risks and uncertainties regarding our ability to manufacture our
product candidates on a commercial scale or to supply our product
candidates to our collaborator for use in its product candidates,
risks and uncertainties regarding our and our collaborator's ability
to successfully enroll and conduct preclinical and clinical studies of
product candidates, including our product candidate to treat cancer
described in this release and our collaborator's medical device
product candidates to treat vascular disease, risks and uncertainties
that clinical trial results at any phase of development including
those described in this release may be adverse or may not be
predictive of future results or lead to regulatory approval of any of
our or our collaborator's product candidates, risks and uncertainties
of third-party intellectual property claims relating to our and our
collaborator's product candidates, and risks and uncertainties
relating to regulatory oversight, the timing, scope, cost and outcome
of legal proceedings, including litigation concerning our NF-(kappa)B
patent portfolio, future capital needs, key employees, dependence on
our 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, as
amended, for the fiscal year ended December 31, 2004. 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, 617-621-2345