Mallinckrodt plc and Questcor Pharmaceuticals, Inc. have entered into a definitive merger agreement under which Mallinckrodt will acquire Questcor in a transaction valued at approximately $5.6 billion. The transaction, subject to customary closing conditions, is expected to be completed in 3Q14.   With the acquisition, Mallinckrodt gains Questcor’s H.P. Acthar Gel, expanding its portfolio of specialty pharmaceutical brands, including OFIRMEV, EXALGO and XARTEMIS XR. In 2013, Acthar generat...