
Shares of drug developer Milestone Pharmaceuticals MIST.O fall as much as 66.7% to record low of 75 cents
Stock down 59% at 92 cents in afternoon trade
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
Including session moves, stock down 60% YTD