In the year’s second biggest M&A deal, Merck & Co. Inc. will take over pulmonary and hematologic specialist Acceleron Pharma Inc. for $11.5 billion. The acquisition brings Merck a pair of potential blockbuster drugs, one of them already marketed. There is sotatercept, in development for treating pulmonary hypertension (PH), and also Reblozyl (luspatercept-aamt), the first and only erythroid maturation agent approved in the U.S., Europe and Canada for treating anemia in certain blood disorders.