New Study on ARIAD's Cell-Signaling Regulation Technology Highlights Breakthrough in Stem Cell Therapy

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Sept. 16, 2002--ARIAD Pharmaceuticals, Inc. (Nasdaq:ARIA) today announced findings that make possible the use of stem cell therapy to potentially cure genetic blood diseases, such as thalassemia and sickle cell disease, as well as chronic diseases, such as congestive heart failure and diabetes.

In a study published today in the journal Blood, a collaborative team of scientists from the University of Washington and ARIAD demonstrated that using ARIAD's cell-signaling regulation technology, a small number of genetically modified bone marrow cells can be activated to grow in vivo into a large population of therapeutic cells, opening up the possibility of curing previously untreatable diseases.

These results are particularly important, because this is the first in vivo study in large animals to show that specific therapeutic cells can be coaxed into growing vigorously by using a specially designed class of small-molecule drugs suitable for clinical use. Studies of cellular therapy in dogs are considered highly predictive of findings in humans.

"Dr. Blau and his colleagues have overcome one of the key obstacles to the broader application of stem cell therapy. Providing genetically corrected cell populations with a survival advantage has broad clinical implications and may create new opportunities to treat incurable blood diseases, as well as other life-threatening conditions," says Harvey J. Berger, M.D., chairman and chief executive officer of ARIAD.

Thus far, the only clinical successes in stem cell gene therapy have been in patients with severe combined immunodeficiency (SCID), because the gene-modified cells in these patients have a natural survival advantage relative to their unmodified counterparts. With the use of the ARGENT(TM) cell-growth switch, it may be possible to achieve the same outcome with other cell types that lack such a selective advantage.

In the newly published research, canine bone marrow cells were engineered with the ARGENT cell-growth switch. Following infusion of the engineered cells into dogs, the activating small-molecule drug induced robust production of genetically modified blood cells derived from the precursor cells, giving these potentially therapeutic cells a significant survival advantage in vivo. Conversely, production ceased when the activating drug was withheld.

The paper describing the research by Dr. Blau and his colleagues, "Pharmacologically regulated in vivo selection in a large animal," appears in the September 15, 2002 issue of Blood and is available online at the journal's website (http://www.bloodjournal.org/).

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 related to the discovery, development, and use of drugs that modulate the NF-(kappa)B pathway, 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.

CONTACT:

ARIAD Pharmaceuticals, Inc.

Tom Pearson, 610/407-9260

Kathy Lawton, 617/621-2345