
Shares of drug developer Milestone Pharmaceuticals MIST.O fall 62.7% to 84 cents premarket
US FDA declined to approve MIST's nasal spray, Cardamyst, to treat a type of heart condition, company says
FDA raised no concerns about clinical safety or efficacy, but highlighted two key chemistry, manufacturing and controls issues - MIST
Issues include needing additional information on nitrosamine impurities, cancer-causing compounds formed during manufacturing and an inspection of a testing facility
Shares up 25% in the last 12 months, as of last close