Marathon Pharmaceuticals is selling its controversial Duchenne muscular dystrophy drug, Emflaza, for $140 million, however it is unclear whether the company will drastically increase its profits by selling the priority review voucher it was rewarded for getting the drug approved. Key lawmakers have said Marathon gamed the PRV system, which is meant to incentivize research on rare diseases, and have asked the company to specify its plan for the voucher -- which could fetch hundreds of millions of dollars. Marathon's...