EXHIBIT 99.1

ARIAD Initiates Phase 2 Clinical Trial of AP23573 in Patients with Recurrent
                   or Persistent Endometrial Cancer;
     Over 40,000 New Cases of Endometrial Cancer Expected in 2005

    CAMBRIDGE, Mass.--(BUSINESS WIRE)--June 30, 2005--ARIAD
Pharmaceuticals, Inc. (Nasdaq:ARIA) today announced initiation of
enrollment of patients with recurrent or persistent endometrial cancer
in a global Phase 2 clinical trial of its novel mTOR inhibitor,
AP23573, as a single agent. Endometrial cancer is the most common
gynecologic malignancy, including ovarian cancer.
    This non-randomized study will evaluate the clinical benefit of
AP23573 in well-characterized endometrial cancer patients. Up to
approximately 45 patients will be enrolled in the trial at several
centers in the United States and Europe. AP23573 will be administered
intravenously using a daily dosing regimen. Patients will be followed
for at least six months after enrollment but may continue on AP23573
if they have clinical benefit. Data on multiple mTOR-pathway
biomarkers, including functional imaging in a subset of patients, will
be obtained to help identify patients who are most likely to benefit
from treatment with AP23573.
    "Biological and genetic studies of mTOR-pathway activation in
endometrial cancer highlight the importance of this pathway in these
tumors and the potential for increased sensitivity to mTOR inhibition.
These data led us to include endometrial cancer as another potential
indication with substantial unmet medical need that warrants further
study with AP23573 in Phase 2 trials," said Tim Clackson, Ph.D., chief
scientific officer and senior vice president of ARIAD.

    About Endometrial Cancer

    It is expected that over 40,000 new cases of endometrial cancer
will be diagnosed in the U.S. in 2005, and over 7,000 deaths will
occur. Endometrial cancer, which develops from the inner lining of the
uterus is the most common cancer in the female reproductive system.
Prognosis for patients is primarily based on the time of diagnosis
relative to the stage of the cancer. Initial treatment consists of
surgery, alone or in combination with radiation, or hormonal therapy.
For those women with disease progression, chemotherapy is the only
currently available treatment option, and limited benefit has been
seen in such cases, emphasizing the need for new molecularly targeted
therapies.

    About AP23573

    ARIAD's 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 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.
             Edward Fitzgerald (Investors)
             617-621-2345
             or
             Pure Communications
             Andrea Johnston (Media)
             910-681-1088