Etripamil (AFib-RVR) - (ReVeRA-301)

Aug. 21, 2026: Milestone Pharmaceuticals (NASDAQ: MIST) announced first-patient enrollment in ReVeRA-301, a pivotal Phase 3 randomized, double-blind, placebo-controlled trial of etripamil nasal spray for atrial fibrillation with rapid ventricular rate (AFib-RVR). The multinational study will enroll about 150 patients, who will self-administer the same 70 mg repeat-dose regimen already FDA-approved for PSVT under CARDAMYST.

The primary endpoint is reduction in ventricular rate within 30 minutes; a key secondary endpoint is symptom improvement measured by patient-reported outcomes. The trial is designed for use in medically unsupervised settings such as at home.

The program builds on Phase 2 ReVeRA-201 data, which the company said showed a single 70 mg dose reduced ventricular rate and improved symptom relief and treatment satisfaction in symptomatic AFib-RVR patients treated in an emergency room setting.

Milestone said it is pursuing a single-study supplemental NDA pathway for AFib-RVR based on safety data to date. The release also notes CARDAMYST (etripamil) is already FDA-approved in adults for conversion of acute symptomatic PSVT to sinus rhythm, and that etripamil is in Phase 2 development for pediatric PSVT.