ARIAD Appoints Lee C. Steele as New Chief Financial Officer, Treasurer, and Senior Vice President.

Business Editors

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Jan. 4, 2001

ARIAD Pharmaceuticals, Inc. (Nasdaq: ARIA) today announced the appointment of Mr. Lee C. Steele as its chief financial officer, treasurer, and senior vice president.

Mr. Steele, currently chief financial officer and treasurer of American Science & Engineering, Inc. (AS&E), will be responsible for corporate finance, treasury, investor relations, and administration at ARIAD and will be a member of the Company's executive committee. Mr. Steele replaces Mr. Jay LaMarche, one of ARIAD's founders, who retired for health reasons but remains a member of the Company's Board of Directors.

Mr. Steele joins ARIAD after six years as a senior officer at AS&E, a publicly held manufacturer of sophisticated instrumentation based on the physics of low-energy x-rays. He played a pivotal role in positioning AS&E as a global leader in the commercialization of high-tech x-ray security systems and linear accelerators for medical, scientific and other applications. Previously, Mr. Steele was a management consulting partner at Deloitte and Touche and a principal at Asset Management, Inc., a consulting and financial advisory firm. Mr. Steele earned an M.B.A. from Harvard Business School and a B.S. from Case Western Reserve University.

"Mr. Steele's extensive experience in finance, corporate acquisitions, and equity and debt financings will be critically important to ARIAD in achieving its commercial objectives. Lee brings twenty-five years of focused business expertise to our executive team," said Harvey J. Berger, M.D., chairman and chief executive officer of ARIAD.

Mr. Steele added, "I view this position as a great opportunity to use the skills I have gained through my activities at AS&E and in consulting. I look forward to joining the senior management team at ARIAD and helping build a substantial commercial enterprise with significant shareholder value."

ARIAD Pharmaceuticals, Inc. (www.ariad.com) is a leader in the discovery and development of gene therapy, cell therapy, stem cell therapy and protein therapy products featuring dose-dependent regulation by small-molecule drugs, as well as small-molecule inhibitors of signal transduction.

Some of the matters discussed in this news release are forward-looking statements that involve risks and uncertainties, which include, but are not limited to, the risks and uncertainties regarding the Company's clinical and preclinical studies, the ability of the Company to conduct such studies of its products and the results of such studies, as well as risks and uncertainties relating to economic conditions, markets, products, competition, intellectual property, services and prices, key employees, future capital needs, dependence on our collaborators and other factors under the heading "Cautionary Statement Regarding Forward-Looking Statements" in ARIAD's Annual Report on Form 10-K for the fiscal year ended December 31, 1999 filed with the Securities and Exchange Commission.