Milestone Pharmaceuticals Inc. (NASDAQ: MIST) has initiated the Phase 3 ReVeRA-301 trial for its etripamil nasal spray, assessing the treatment in patients with atrial fibrillation and rapid ventricular rate (AFib-RVR).
The study, which aims to enroll approximately 150 patients across North America and international sites, will evaluate the efficacy of a 70 mg repeat-dose regimen of etripamil. Patients will self-administer the treatment in medically unsupervised settings, such as their homes, when symptoms arise. The primary endpoint measures the reduction in ventricular rate within 30 minutes of administration, alongside patient-reported symptom improvement.
The trial follows Phase 2 results from the ReVeRA-201 study, which demonstrated that a single 70 mg dose reduced ventricular rate, improved symptom relief, and increased treatment satisfaction in an emergency room setting. Milestone is pursuing a single-study supplemental new drug application pathway for AFib-RVR treatment, relying on existing safety data.
Current standard treatments for AFib-RVR typically require emergency department visits for intravenous medications or electrical cardioversion. Market research indicates that 30-40% of atrial fibrillation patients experience at least one episode of rapid ventricular rate per year requiring urgent medical attention. U.S. Healthcare Cost and Utilization Project data from 2016-2020 shows that 0.44% of all emergency department visits had a primary diagnosis of atrial fibrillation, with nearly half resulting in inpatient admission.
