The US Food and Drug Administration approved CARDAMYST (etripamil) nasal spray for the conversion of acute symptomatic episodes of paroxysmal supraventricular tachycardia to sinus rhythm in adults, representing the first FDA-approved pharmacologic option for this indication in more than 30 years. The approval introduces a rapid-acting, self-administered therapy that can be used outside the emergency department.

CARDAMYST is a calcium channel blocker formulated as an intranasal spray and intended for use at the onset of symptoms. Paroxysmal supraventricular tachycardia (PSVT) is characterized by sudden episodes of rapid heart rate, often exceeding 150 to 200 beats per minute, and is associated with palpitations, dyspnea, dizziness, and chest discomfort. Until now, effective treatment for PSVT typically required intravenous administration in a monitored health care setting; the approval allows adults to self-administer etripamil outside the emergency department or other health care settings.

FDA approval was supported by a clinical development program that included safety data from more than 1,800 participants and more than 2,000 documented episodes. Efficacy data were primarily derived from the Phase 3 RAPID trial, a global, randomized, double-blind study comparing etripamil with placebo. In that trial, 64% of participants who self-administered etripamil converted to sinus rhythm within 30 minutes compared with 31% in the placebo group, with a hazard ratio of 2.62 and a p value less than 0.001. Median time to conversion was 17 minutes with etripamil versus 54 minutes with placebo. At 1 hour, 73% of participants treated with etripamil had converted to sinus rhythm.

The safety profile was consistent across subgroups, including patients receiving background beta blockers or calcium channel blockers. The most frequently reported adverse events were mild to moderate and localized nasal discomfort, congestion, rhinorrhea, throat irritation, and epistaxis. Fewer than 2% of participants discontinued treatment because of adverse events.

CARDAMYST is expected to be available through retail pharmacies in early 2026. Milestone reported plans to enter a Phase 3 program for etripamil in atrial fibrillation with rapid ventricular rate and pursue a supplemental New Drug Application for a potential second indication.

Source: Milestone Pharmaceuticals