ARIAD Scientists First to Publish Studies On Direct Small-Molecule Regulation of Natural Cellular Genes; Technological Advance Published Today in Nature Biotechnology.

Business/Technology Editors and Health/Medical Writers

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ARIAD Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced the results of comprehensive studies by a team of its scientists demonstrating, for the first time, the use of proprietary small-molecule drugs to directly regulate naturally occurring genes through specific activators - a technological advance with major therapeutic implications. Controlled expression of natural cellular genes produces the identical set of protein variants to that expected from physiologic activation of the natural gene, at the specific time and level of activity required by the therapeutic intervention. Since each of the protein variants often has different therapeutic effects, it is now possible to deliver, in a precisely regulated manner, the family of proteins encoded by a desired natural cellular gene, resulting in beneficial therapeutic effects.

"A number of biotechnology companies are pursuing the activation of natural cellular genes as a therapeutic strategy," said Harvey J. Berger, M.D., chairman and chief executive officer of ARIAD. "Our small-molecule regulation technology can transform these treatments, including those already in clinical development, into pharmaceutical products that may be better accepted by physicians, patients and regulatory authorities. The newly published studies highlight the ever-expanding utility of ARIAD's cell-signaling regulation technology in products."

The paper by Pollock et al., "Regulation of endogenous gene expression with a small-molecule dimerizer," appears today in the July 2002 issue of Nature Biotechnology and can be accessed at the journal's website (http://www.nature.com/nbt/).

ARIAD is engaged in the discovery and development of breakthrough medicines that regulate cell signaling with small molecules. The Company's development pipeline includes: a drug candidate that controls cell proliferation and nutrient uptake by tumors to treat cancer; a bone-targeted drug candidate to treat the complications of cancer that has spread to bone; a regulated protein therapy product candidate to treat anemia in which the production of erythropoietin is controlled in vivo using an orally administered drug; a T cell immunotherapy product candidate in which a non-immunosuppressive drug may be used to treat graft-vs-host disease following donor bone marrow transplantation - a therapy for cancer and other immune and blood diseases; and dual-action drug candidates that block bone resorption and stimulate bone formation to treat osteoporosis. 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, 2001. 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.