Exhibit 99.1

ARIAD First to Report High-Resolution Picture of Key Cancer-Associated
Protein Bound to Potent Inhibitor Drug; Findings Featured in
International Cancer Conference Press Briefing

    CAMBRIDGE, Mass.--(BUSINESS WIRE)--Nov. 19, 2003--ARIAD
Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced, at a press
briefing sponsored by the organizers of the AACR-NCI-EORTC
international cancer conference, the first reported high-resolution
structure of a small-molecule drug bound to an important
cancer-associated protein (kinase) target known as Src. The small
molecule is one of ARIAD's lead oncology product candidates, AP23464 -
a highly potent inhibitor of Src, which plays a critical role in the
growth, proliferation and spread of many of the most common and
difficult-to-treat tumors.
    The first high-resolution picture of Src bound to a small-molecule
inhibitor is an important scientific breakthrough. Each of the atoms
in the protein and drug, and their interactions, are depicted in a
three-dimensional display that was highly valuable in the design of a
selective kinase inhibitor capable of potently inhibiting multiple
clinically relevant targets, including the Src and Abl proteins. While
the inhibition of Src by AP23464 positions it as a novel treatment
option for solid tumors, including metastasis, its equally potent
inhibition of the Abl protein highlights its potential use in treating
certain leukemias.
    "We anticipate that our dual Src/Abl inhibitor should have broad
therapeutic potential in patients with many types of cancer and expect
to initiate phase 1 clinical trials of AP23464 next year," said Harvey
J. Berger, M.D., chairman and chief executive officer of ARIAD.
    Of the 800 abstracts that will be presented at the International
Conference on Molecular Targets and Cancer Therapeutics, jointly
sponsored by the American Association for Cancer, the National Cancer
Institute, and the European Organization for Research and Treatment of
Cancer (AACR-NCI-EORTC), three were featured in this morning's
conference press briefing, including the abstract highlighting the
development of ARIAD's product candidate to treat certain leukemias
and metastatic cancers.
    The abstract by David Dalgarno, et al, "Structure-based design and
X-ray crystallographic analysis of a potent and selective Src tyrosine
kinase inhibitor for the treatment of cancer," is available on the
website for the meeting (http://www.aacr.org/2003mtct1.asp).
    ARIAD is engaged in the discovery and development of breakthrough
medicines that regulate cell signaling with small molecules. The
Company is developing a comprehensive approach to the treatment of
cancer and is primarily focused on a series of product candidates for
targeted oncology indications. ARIAD also has an exclusive license to
pioneering technology and patents related to the discovery,
development and use of drugs that regulate NF-(kappa)B cell-signaling
activity, which has been implicated in many major 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
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
             Kathy Lawton, 617/621-2345