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

                   ARIAD Reports Second Quarter 2005 Results;
            Key Clinical and Regulatory Milestones Achieved Ahead of
            Schedule and AP23573 Commercialization Goals Highlighted

    CAMBRIDGE, Mass.--(BUSINESS WIRE)--Aug. 1, 2005--ARIAD
Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced financial results
for the quarter ended June 30, 2005 and provided an update on progress
towards achievement of 2005 goals.
    "Based on our progress during the second quarter of 2005, we are
now well positioned to pursue our next set of critical objectives: a
partnership to commercialize AP23573 outside the U.S., readiness to
launch AP23573 in the U.S. ourselves, and execution of the initial
AP23573 registration trial in patients with soft-tissue and bone
sarcomas. If all goes well, we could have our first cancer product
approval and product revenues in 2007," said Harvey J. Berger, M.D.,
chairman and chief executive officer of ARIAD.

    Financial Highlights

    For the quarter ended June 30, 2005, the Company reported a net
loss of $14.1 million, or $0.27 per share, as compared to $9.2
million, or $0.18 per share, for the quarter ended June 30, 2004. The
increase in net loss for the quarter is due primarily to higher R&D
expenses resulting from execution of the global development plan for
its lead cancer product candidate, AP23573. For the six months ended
June 30, 2005, cash used in operations was $20.7 million, consistent
with the Company's guidance for 2005 of $39 million to $42 million.
    The Company ended the second quarter 2005 with $50.2 million in
cash, cash equivalents, and marketable securities, compared with $75.5
million at the end of 2004.

    AP23573 Highlights

    During the second quarter, the Company achieved several important
milestones in the development of AP23573 as its lead cancer product
candidate:

    --  Received fast-track designation for AP23573 from the U.S. Food
        and Drug Administration for the treatment of soft-tissue and
        bone sarcomas.

    --  Selected the initial registration path for AP23573 - treatment
        of soft tissue and bone sarcomas - and engaged with U.S. and
        European regulatory agencies to consider the potential design
        of clinical trials required for registration.

    --  Presented positive early Phase 2 results in patients with
        soft-tissue and bone sarcomas at the annual meeting of the
        American Society of Clinical Oncology. Completed enrollment in
        three of the four sarcoma sub-groups included in this trial
        with the expectation of achieving full study enrollment
        shortly.

    --  Achieved significant progress in enrollment of ongoing Phase
        1b and 2 clinical trials of AP23573 in patients with brain
        cancer and hematologic malignancies.

    --  Initiated several additional multi-center clinical trials of
        AP23573, including:

        --  Phase 2 studies in the U.S. in patients with
            hormone-refractory prostate cancer, and in the U.S. and
            Europe in patients with progressive endometrial cancer;

        --  Phase 1b studies in Europe combining AP23573 with two
            different chemotherapeutic agents in patients with
            progressive breast, ovarian, non-small-cell lung and
            prostate cancers, as well as certain sarcomas;

        --  Phase 1b study of the oral dosage form of AP23573 in
            patients with various solid tumors, evaluating several
            dosing regimens and doses, with the goal of conducting the
            first registration trial of AP23573 with the tablet form
            of the drug.

    --  Received the first-ever Symbol of Caring Award from the
        Sarcoma Foundation of America for development of AP23573 -
        potentially the first new treatment for soft-tissue and bone
        sarcomas in over twenty years.

    --  Assisted partner, Medinol, Ltd., achieve significant progress
        in the development of AP23573 drug-eluting stents for
        prevention of coronary artery reblockage.

    AP23573 Development Goals

    In light of the Company's progress to date in the clinical trials
of AP23573, ARIAD is actively pursuing the following commercialization
and clinical goals for its lead oncology product candidate:

    --  Establish a partnership with a major pharmaceutical and/or
        biotechnology company for commercialization of AP23573 outside
        the U.S. - the top priority for the Company's business team.

    --  Present updated results from Phase 2 clinical trial in
        sarcomas and initial data from Phase 1 and 2 clinical trials
        in hematologic malignancies and solid tumors at key medical
        and scientific meetings beginning in 2H05.

    --  Initiate global registration trial(s) in soft-tissue and bone
        sarcomas in 1H06.

    --  Define follow-on oncology indications and registration paths
        for AP23573 in 2H06.

    --  File marketing authorization(s) for AP23573 in 1H07.

    --  Launch AP23573 in the U.S. potentially in 2H07, subject to
        regulatory approvals.

    Upcoming Scientific Meetings

    Timothy P. Clackson, Ph.D., chief scientific officer of ARIAD,
will present a discussion of cancer growth regulators, "Targeting mTOR
and Akt," on August 26, 2005 at the 4th International Congress on
Targeted Therapies in Cancer at the Omni Shoreham Hotel in Washington,
D.C.

    Upcoming Investor Meetings

    ARIAD management will present updated overviews of the Company's
progress and plans at several investor conferences - all to be webcast
- - including the following:

    --  Adams Harkness 25th Annual Summer Seminar at the Marriott Long
        Wharf Hotel in Boston, Massachusetts, August 2, 2005.

    --  Bear Stearns 18th Annual Healthcare Conference at the Grand
        Hyatt Hotel in New York, New York, September 12 - 13, 2005.

    --  UBS 2005 Global Life Sciences Conference at the Grand Hyatt
        Hotel in New York, New York, September 26-29, 2005.

    --  Rodman & Renshaw Techvest 7th Annual Healthcare Conference at
        the New York Palace Hotel, New York, New York, November 7-9,
        2005.

    --  Lazard Health Care Conference at the New York Palace Hotel in
        New York, New York, November 29-30, 2005.

    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, including those
costs related to the global development plan for AP23573 described in
this release, 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, including our product candidate to treat various
cancers described in this release and our collaborator's medical
device product candidate 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 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.

             ARIAD PHARMACEUTICALS, INC. AND SUBSIDIARIES
            CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

In thousands,             Three Months                Six Months
 except share                Ended                      Ended
 and per share              June 30,                   June 30,
 data           -------------------------   -------------------------
                      2005          2004          2004          2004
                -----------   -----------   -----------   -----------
                       (Unaudited)                 (Unaudited)
Total license
 revenue       $       350   $       188   $       654   $       378
                -----------   -----------   -----------   -----------

Operating
 expenses:
   Research and
    development     12,093         7,102        22,747        11,435
   General and
    adminis-
    trative          2,600         2,565         4,916         4,783
                -----------   -----------   -----------   -----------
     Total
      operating
      expenses      14,693         9,667        27,663        16,218
                -----------   -----------   -----------   -----------

Other income,
 net                   260           234           580           360
                -----------   -----------   -----------   -----------
Net loss       $   (14,083 ) $    (9,245 ) $   (26,429 ) $   (15,480 )
                -----------   -----------   -----------   -----------
                -----------   -----------   -----------   -----------
Net loss per
 common share
(basic and
 diluted)      $      (.27 ) $      (.18 ) $      (.50 ) $      (.31 )
                -----------   -----------   -----------   -----------
                -----------   -----------   -----------   -----------
Weighted
 average number
 of
shares of
 common stock
outstanding
 (basic and
 diluted)       52,901,275    52,416,929    52,854,653    49,978,892



           CONDENSED CONSOLIDATED BALANCE SHEET INFORMATION
In thousands                                          June  December
                                                       30,     31,
                                                      2005    2004
                                                   --------  --------
                                                  (Unaudited)

Cash, cash equivalents and marketable securities     $50,169  $75,506
Total assets                                         $64,955  $87,189
Total liabilities                                    $23,100  $19,749
Stockholders' equity                                 $41,855  $67,440

    CONTACT: ARIAD Pharmaceuticals, Inc.
             Edward Fitzgerald (Investors)
             617-621-2345
             or
             Pure Communications
             Andrea Johnston (Media)
             910-616-5858