Credit Suisse Securities (USA) LLC is acting as sole underwriter for the offering. ARIAD expects the closing of the offering to occur on or about October 25, 2006, subject to customary closing conditions. As a result of this transaction, ARIAD will have no remaining shares available under shelf registration statements.

ARIAD is engaged in the discovery and development of breakthrough medicines to treat cancer by regulating cell signaling with small molecules.

Cancer patients throughout the world are in urgent need of better treatment options. At ARIAD, we believe the way to breakthrough cancer therapies for many forms of cancer is through the regulation of cell-signaling pathways. We are building a fully integrated oncology company founded on our expertise in cell-signaling and moving rapidly to advance our lead product candidate and pipeline candidates through development to the patients who need them.