LEXINGTON, Mass. (AP) – Cubist Pharmaceuticals Inc. has completed its acquisition of fellow drugmaker Adolor Corp. for about $221 million.

Cubist said it bought all of Adolor’s outstanding shares for $4.25 per share in cash. Adolor shareholders will also receive up to an additional $4.50 per share if certain milestones are met in the development of a potential treatment for chronic, opioid-induced constipation, Cubist said.

Cubist’s most recent tender offer for Adolor shares expired on Dec. 9. At that time, about 43.3 million shares had been validly tendered, representing about 83% of Adolor’s outstanding shares. All of those shares were accepted for payment, the company said.

Under the terms of the acquisition, a Cubist subsidiary exercised its option to buy newly issued shares from Adolor for $4.76 per share. After that purchase, the subsidiary owned enough shares to acquire Adolor, the company said.

The Associated Press