"Acceleron Pharma, Inc. a privately held Cambridge biopharmaceutical company, announced it has been granted fast-track designation for a potential treatment of Duchenne muscular dystrophy. Fast-track status is to speed review of new drugs "intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs," Acceleron said. The drug candidate is ACE-031, "a protein therapeutic being developed to increase muscle mass and strength."