Milestone Pharmaceuticals' new drug application for etripamil nasal spray to treat paroxysmal supraventricular tachycardia has been declined by the FDA.

This decision was based on two chemistry, manufacturing, and control issues and a request for a facility inspection. The FDA also sought additional data on nitrosamine impurities. Despite the concerns, the FDA did not question the safety or efficacy of the nasal spray. The company reported positive results from a late-stage study, indicating that the self-administered nasal spray was successful in helping a significant number of patients return to normal heart rhythm.