Irish specialty drug maker Mallinckrodt will acquire Anaheim-based Questcor for $5.6 billion, expanding Mallinckrodt's offering of speciality pharmaceuticals. The deal, announced Monday, will have Questcor shareholders receive $30 per share in cash and 0.897 of a Mallinckrodt share, or a total of $88.08 per share as of the April 4 closing price. That's 27 percent above the April 4 closing price for Questcor. Mallinckrodt's CEO Mark Trudeau has strived to reduce the company's exposure to medical imaging and focus on the specialty pharmaceuticals business, and the acquisition will give the company access to Questcor's primary drug Acthar, which is used to treat autoimmune and inflammatory conditions. Sales of the drug last year rose 50 percent to $761.3 million. "We are now well on our way to becoming a leader in the development and commercialization of specialty therapeutics around the world," Trudeau said in the statement. The deal is another example of U.S. companies moving offshore to enjoy another country's lower tax rate, in this case Ireland. Questcor paid a 35 percent tax rate last year, whereas Mallinckrodt paid 29 percent.