Exhibit 99.1

ARIAD Discovers New and Broader Potential Cancer Indications for Its
Oncology Product Candidate, AP23464; Research Presented at Keystone
Meeting on Molecular-Based Cancer Therapies

    CAMBRIDGE, Mass.--(BUSINESS WIRE)--Feb. 24, 2004--ARIAD
Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced, for the first
time, results of new studies supporting expansion of the potential
clinical indications for its molecularly targeted product candidate,
AP23464, to include specific difficult-to-treat solid tumors, such as
breast, ovarian, prostate, liver, lung, kidney, brain, stromal and
colorectal cancers.
    These studies demonstrate that AP23464 potently blocks the
proliferation of cancer cells whose activity is controlled by the key
molecular targets of well-known marketed oncology drugs and/or those
in late-stage clinical development. The list of such drugs and their
oncogenic kinase targets includes: Iressa(TM), Tarceva(TM) and
Erbitux(TM) (EGFR), Herceptin(R) (HER2), BAY-43-9006 (Raf), and
Gleevec(TM) (KIT).
    The presentation by Tomi K. Sawyer, Ph.D. of ARIAD at the Keystone
Conference on Protein Kinases and Cancer: the Promise of
Molecular-based Therapies shows that when tested against over 120
potential molecular targets, AP23464 selectively and potently blocks a
limited number of oncogenic proteins - in addition to those previously
reported (Src and Abl) - which share similar sites of molecular
interaction in their drug-binding pocket, including EGFR, HER2, Raf,
KIT, PDGFR and FGFR3.
    Previously, AP23464 was being developed solely to treat certain
forms of leukemia (based on its inhibition of the Abl protein kinase
and its mutant forms) and the spread of cancer to distant sites (based
on its inhibition of the Src protein kinase).
    "A belief commonly held by cancer researchers is that the cure for
cancer will not be found by blocking any single cancer-causing target,
because the growth of most cancers is driven by more than one
over-activated or over-expressed oncogenic protein," said Harvey J.
Berger, M.D., chairman and chief executive officer of ARIAD. "A
product of our internal drug-discovery efforts, AP23464 represents a
novel small-molecule drug to treat both solid tumors and their
metastatic spread with a single molecularly targeted agent."
    Further information about the conference can be found on the web
at
http://www.keystonesymposia.org/Meetings/ViewMeetings.cfm?MeetingID
=663. (Due to the length of this URL, it may be
necessary to copy and paste this hyperlink into your Internet
browser's URL address field.)
    ARIAD is engaged in the discovery and development of breakthrough
medicines to treat cancer 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. ARIAD also 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.
    Additional information about ARIAD can be found on the web at
http://www.ariad.com.

    Iressa is a trademark of AstraZeneca PLC, Tarceva is a trademark
of OSI Pharmaceuticals, Inc. Erbitux is a trademark of ImClone
Systems, Inc. Herceptin is a registered trademark of Genentech, Inc.
BAY-43-9006 is a development candidate of Bayer AG and Onyx
Pharmaceuticals, Inc. Gleevec is a trademark of Novartis AG.

    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
             ARIAD Pharmaceuticals, Inc.
             Kathy Lawton, 617-621-2345