Clinical Data on ARIAD's Novel mTOR Inhibitor, AP23573, to Be Presented at the American Society of Oncology Annual Meeting; Five Presentations Highlight AP23573 Phase 2 and Phase 1 Clinical Trials and Use of Biomarkers and Imaging.

CAMBRIDGE, Mass. -- ARIAD Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced that clinical investigators from leading cancer centers will present, for the first time, data from Phase 2 and Phase 1 clinical trials of the Company's novel mTOR inhibitor, AP23573, at the annual meeting of the American Society of Clinical Oncology (ASCO) in Orlando, Florida, May 13 to 17, 2005. Five presentations will highlight new clinical results on AP23573 as a single agent in solid tumors (e.g., soft-tissue and bone sarcomas) and hematologic malignancies (e.g., leukemias and lymphomas), including studies with biomarkers and functional imaging.

"AP23573 recently was designated as a fast-track product for the treatment of soft-tissue and bone sarcomas by the U.S. Food and Drug Administration based, in part, on the agency's review of our Phase 2 and Phase 1 clinical data. The interim results of our Phase 2 clinical trial in this indication will be presented for the first time at the ASCO meeting," said Harvey J. Berger, M.D., chairman and chief executive officer of ARIAD.

The schedule and meeting places for the general poster and poster-discussion sessions, together with the abstract and poster numbers, are listed below:

Sunday, May 15, 2005 at 8:00 a.m. to 12:00 p.m.

Abstract No. 3043; Poster No. J5

"Development of a pharmacokinetic (PK) model and assessment of patient (pt) covariate effects on dose-dependent PK following different dosing schedules in two phase I trials of AP23573 (AP), an mTOR inhibitor"

Presenter: Apurva A. Desai, M.D.

Location: Level 2, Hall C

Sunday, May 15, 2005 at 1:00 p.m. to 5:00 p.m.

Abstract No. 9028; Poster No. 15

"Early response evaluation of therapy with AP23573 (an mTOR inhibitor) in sarcoma using (18F)-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) scan"

Presenter: Kamalesh K. Sankhala, M.D.

Location: Level 2, Hall F4

Monday, May 16, 2005 at 8:00 a.m. to 12:00 p.m.

Abstract No. 9068; Poster No. N13

"A phase 2 study of AP23573 (an mTOR inhibitor) in patients (pts) with advanced sarcomas"

Presenter: Sant P. Chawla, M.D.

Location: Level 2, Hall C

Monday, May 16, 2005 at 1:00 p.m. to 5:00 p.m.

Abstract No. 3033; Poster No. 20

"Pharmacodynamic study of skin biopsy specimens in patients (pts) with refractory or advanced malignancies following administration of AP23573, an mTOR inhibitor"

Presenter: Victor M. Rivera, Ph.D.

Location: Level 3, 314A

Tuesday, May 17, 2005 at 8:00 a.m. to 12:00 p.m.

Abstract No. 6631; Poster No. D8

"A phase 2 clinical trial of AP23573, an mTOR inhibitor, in patients with relapsed or refractory hematologic malignancies"

Presenter: Eric Feldman, M.D.

Location: Level 2, Hall F4

The following abstract will be published in the Proceedings of the American Society of Clinical Oncology:

"PTEN expression in archival tumor samples in patients (pts) with advanced malignancies in two phase I studies of AP23573 (AP), an mTOR inhibitor" L. Janisch, A. A. Desai, M. Mita, R. Parsons, M. Goldston, H. L. Knowles, C. L. Bedrosian, E. Rowinsky, A. Tolcher, and M. J. Ratain.

About AP23573

The 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 including those mentioned in this release 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.