Cubist Pharmaceuticals Announces Expiration of Hart-Scott-Rodino Waiting Period for Acquisition of Adolor

Cubist Pharmaceuticals, Inc.

and Adolor Corporation

today announced the expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (HSR Act) in connection with Cubist's previously announced acquisition of Adolor. Expiration of the HSR waiting period satisfies one of the conditions to the closing of the merger transaction. The closing of the transaction also is conditioned on the tender of a majority of the outstanding shares of Adolor's common stock and the satisfaction of other customary closing conditions. Cubist initiated a cash tender offer on November 7, 2011 to purchase all outstanding shares of Adolor common stock. The tender offer will expire at 12:00 midnight, New York City time, on December 6, 2011, unless extended or terminated. Upon the successful closing of the tender offer, stockholders of Adolor will receive $4.25 per share in cash and one Contingent Payment Right (CPR) entitling the holder to receive additional cash payments of up to $4.50 for each share they own if certain regulatory approvals and/or commercialization milestones for ADL5945 are achieved.