Milestone Pharmaceuticals Inc is a biopharmaceutical company dedicated to developing and commercializing etripamil for the treatment of cardiovascular medicines. Etripamil is a calcium channel blocker developed as a rapid-onset nasal spray to be administered by the patient to treat episodes of paroxysmal supraventricular tachycardia, or PSVT. The company has an ongoing Phase 2 clinical trial for patients with atrial fibrillation experiencing a rapid ventricular rate (AFib-RVR).