ARIAD Announces Underwriters' Exercise of Over-Allotment Option

ARIAD Pharmaceuticals, Inc.

today announced that the underwriters of its previously announced public offering have exercised in full their option to purchase an additional 3,225,000 shares of ARIAD's common stock at a public offering price of $10.42 per share. As a result, ARIAD will issue a total of 24,725,000 shares of common stock for total gross proceeds of approximately $258 million. The aggregate net proceeds to ARIAD from this offering are expected to be approximately $243 million after deducting underwriting discounts and commissions and estimated offering expenses. ARIAD expects to issue and deliver all 24,725,000 shares on or about December 20, 2011, subject to customary closing conditions.