EXHIBIT 99.1
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Interim Phase 2 Data Show Sustained Clinical Benefit in Advanced Sarcoma
Patients Treated with ARIAD's mTOR Inhibitor, AP23573; Results Highlighted at
the AACR-NCI-EORTC News Briefing on New Oncology Drugs

    PHILADELPHIA and CAMBRIDGE, Mass.--(BUSINESS WIRE)--Nov. 16,
2005--ARIAD Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced
interim results of an ongoing Phase 2 clinical trial of its novel mTOR
inhibitor, AP23573, administered as a single agent, in patients with
advanced bone and soft-tissue sarcomas. Twenty-seven percent (27%) of
188 evaluable patients treated with AP23573 had sustained tumor
regression and/or disease stabilization. In addition, the six-month
progression-free survival (PFS) rate in AP23573-treated patients in
the first stage of the trial was 22%, which compares favorably to
historical data on soft-tissue sarcoma patients treated with inactive
chemotherapies for whom the six-month PFS was estimated to be only 8%
(van Glabbeke et al, 2002). Almost all patients in the current trial
had failed alternative anti-cancer treatments and had progressive
disease upon entering the trial.
    "These results provide compelling evidence of the potential
clinical utility of AP23573 in patients with advanced sarcomas - a
cancer with limited treatment options available. AP23573 was chosen by
the AACR-NCI-EORTC (ANE) to be highlighted as one of the exciting new
drugs in development in its news briefing this morning and as an oral
proffered paper in the scientific program tomorrow afternoon," said
Harvey J. Berger, M.D., chairman and chief executive officer of ARIAD.
    "In clinical trials to date, AP23573 treatment has produced a high
level of durable disease stabilization and symptomatic improvement in
patients with advanced sarcomas," said Sant P. Chawla, M.D., one of
the lead investigators in the AP23573 Sarcoma Study Group, who
presented top-line findings from the study at the ANE press briefing
this morning. "As we continue to study AP23573 in sarcomas, I am
excited about the potential AP23573 may offer in the fight against
this devastating cancer."

    Trial Objectives and Design

    The primary objective of this multi-center clinical trial is to
assess the efficacy and safety of AP23573 in four groups of advanced
sarcomas: (a) bone sarcomas (b) leiomyosarcoma, (c) liposarcoma, and
(d) other soft-tissue sarcomas. The trial began patient enrollment
about one year ago in October 2004. Patients receive a fixed dose of
12.5 mg of AP23573 intravenously using a daily dosing regimen of drug
(i.e., five days on, nine days off, drug).
    The trial uses Simon's two-stage design within each of these
sarcoma groups. Four of the initial 19 patients within each group
(stage 1) must exhibit a predefined four-month clinical-benefit
response based on strict Response Evaluation Criteria in Solid Tumors
(RECIST) guidelines before the group can be expanded and enrollment to
at least 44 patients continued. While the patients enrolled in each
cohort in stage 1 of the trial were being followed, further enrollment
into the groups was paused even as additional patients were being
identified for possible enrollment into the second stage. The strict
criteria for continued enrollment were met in all four groups, and
subsequently patients were enrolled in stage 2 of each group.
Enrollment in the trial has exceeded projected targets due to high
patient and clinician interest in AP23573. The trial was designed to
determine whether a clinical-benefit response rate of at least 25% was
achieved in each sarcoma group.
    A total of 212 patients were enrolled to date: 82 in stage 1 and
130 in stage 2. Four of these patients were not dosed, and six
additional liposarcoma patients have been screened and may be
enrolled. Recruitment of patients for the trial is complete. As of the
date of analysis, 81 of the stage 1 patients and 107 of stage 2
patients were evaluable through at least four months on AP23573
treatment - the minimum duration for assessing protocol-defined
clinical-benefit response. Patients continue on AP23573 until their
disease progresses.
    Six-month progression-free survival (PFS), a key endpoint for
evaluating the efficacy of AP23573, was determined using the
Kaplan-Meier analysis of the stage 1 patients and will be determined
in the entire study population once all patients have been followed
further.

    Results of Interim Analysis

    AP23573 treatment achieved the predefined threshold for efficacy
(i.e., at least 25% clinical-benefit response rate) in the bone
sarcoma group (29%) and the most common of the soft-tissue sarcoma
groups - leiomyosarcoma (36%). The results in the liposarcoma group
(17%) are too early to evaluate, as patients have not been followed
long enough, and the results in the other soft-tissue sarcoma group, a
heterogeneous group of multiple different types of soft-tissue
sarcomas, are close to meeting this threshold (22%). The overall
clinical-benefit response rate for the entire trial is 27%.
    Thirty-three percent (33%) of the stage 1 patients (27/81) in the
trial have clinical-benefit responses - sustained anti-tumor activity
- - including four patients with partial responses (confirmed tumor
regression greater than 30%) and 23 patients with stable disease for
at least four months. Clinical-benefit responses were demonstrated in
39% of bone sarcoma patients, 50% of leiomyosarcoma, 21% of
liposarcoma, and 24% of other soft-tissue sarcomas. The six-month PFS
rate in this group is 22%.
    Twenty-two percent (22%) of the evaluable stage 2 patients
(24/107) in the trial have clinical-benefit responses - sustained
anti-tumor activity - at this time. The comparability of the patient
populations in the two stages of the trial is being evaluated further.
Assessment of PFS for the entire trial awaits follow up of the stage 2
patients as the data mature.
    AP23573 was well tolerated at the fixed dose administered, and
adverse events were generally mild to moderate in severity and readily
reversible. The most common treatment-related adverse events were oral
mucositis, rash, fatigue, nausea and hyper-triglyceridemia.
    "These data provide valuable insights into the efficacy and safety
profile of AP23573 in sarcoma patients and further refine our
understanding of those patients likely to benefit most from AP23573.
The results to date have guided our design considerations for the
initial registration trial for AP23573," said Camille L. Bedrosian,
M.D., chief medical officer of ARIAD. "Progression-free survival is a
valuable endpoint in this patient population and may be a strong
predictor of survival benefit. Clearly these data support further
study of AP23573 in a randomized pivotal trial of patients with
advanced sarcomas."
    These clinical results are being presented by Sant P. Chawla, M.D.
on behalf of the AP23573 Sarcoma Study Group as oral presentations at
the 17th ANE International Conference on "Molecular Targets and Cancer
Therapeutics" in Philadelphia, Pennsylvania, November 17, 2005 and the
11th Annual Connective Tissue Oncology Society (CTOS) Meeting in Boca
Raton, Florida, November 20, 2005. More information about the ANE
conference and the news briefings can be found on the web at
http://www.aacr.org.

    Conference Call and Webcast

    ARIAD will hold a live webcast of a conference call at 11:00 a.m.
(EST) today, November 16, 2005, to discuss data from this clinical
trial. To listen to the live webcast, visit the link on the investor
relations section of the Company's website at
http://ariad.com/investor. The call can also be accessed by dialing
866-314-9013 (domestic) or 617-213-8053 (international) five minutes
prior to the start time and providing the passcode, 49060518. A replay
of the call will be available on the ARIAD website approximately two
hours after completion of the call and will be archived for two weeks.

    Reference

    Van Glabbeke, M., Verweij, J., Judson, I., et al. Progression-free
rate as the principal end-point for phase II trials in soft-tissue
sarcomas. European Journal of Cancer 38:543-549, 2002.

    About Sarcoma

    Sarcomas are cancers of the connective tissue, including bones,
muscle, fat, cartilage and joints and do not discriminate 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 subdivided 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.curesarcoma.org
and at http://www.sarcoma.net/facts/htm.

    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. The U.S.
Food and Drug Administration has designated AP23573 both as a
fast-track product and an orphan drug for the treatment of soft tissue
and bone sarcomas, and the European Medicines Agency has also granted
orphan drug status.

    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 or our collaborator's ability to
manufacture our product candidates on a commercial scale or to supply
our product candidates to collaborators, risks and uncertainties
regarding our ability to successfully enroll and conduct preclinical
and clinical studies of product candidates, 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 any collaborator's product candidates, risks
and uncertainties of third-party intellectual property claims relating
to our and any 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 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.
             Ed Fitzgerald (Investors)
             617-621-2345
             or
             Sheryl Seapy (Media)
             Pure Communications
             949-608-0841