Mallinckrodt to buy Questcor for lucrative MS drug

Specialty pharmaceuticals company Mallinckrodt Plc will buy drugmaker Questcor Pharmaceuticals Inc for about $5.6 billion to gain access to its multiple sclerosis drug, Acthar Gel, which is set to hit sales of $1 billion this year. The acquisition is Dublin-based Mallinckrodt’s second in less than two months as it pushes into the lucrative specialty drugs market, which focuses on complex and chronic diseases. Mallinckrodt’s shareholders took a dim view of the deal, however, pushing the company’s shares down as much as 10 percent. Questcor has been facing federal probes into its marketing practices related to Acthar and multiple accusations from short-seller Citron Research.