Aug. 21, 2026 — Milestone Pharmaceuticals Inc. has announced that the first patient has been enrolled in the Phase 3 ReVeRA-301 pivotal trial evaluating etripamil for atrial fibrillation with rapid ventricular rate (AFib-RVR). The trial uses the same repeat-dose regimen as the pivotal trials for etripamil, which is FDA-approved for paroxysmal supraventricular tachycardia (PSVT) as CARDAMYST (etripamil) nasal spray.
“Current management of AFib-RVR in the United States places a substantial burden on both patients and healthcare systems. Because patients experiencing AFib-RVR have no optimally effective self-administered treatment options, many of them require evaluation and treatment in the emergency department,” said James Ip, M.D., Principal Investigator of ReVeRA-301 and Professor of Medicine and Director of Cardiac Pacing and Implantable Devices at Weill Cornell Medicine, and a cardiac electrophysiologist at New York-Presbyterian/Weill Cornell Medical Center. “We are eager to determine if we can clinically validate a safe and effective self-administered treatment option that could reduce reliance on emergency department care for the millions of patients living with AFib-RVR.”
“Enrolling the first patient in the ReVeRA-301 Phase 3 trial marks an important point in the development of etripamil for patients with AFib-RVR,” said David Bharucha, M.D., PhD, FACC, Chief Medical Officer of Milestone Pharmaceuticals. “The FDA approval of etripamil for the treatment of acute, episodic PSVT in adults, and the promising Phase 2 data in patients with AFib-RVR, provide a strong foundation as we advance our clinical development program and evaluate etripamil in this area of substantial unmet medical need. We are activating clinical trial sites across North America and internationally to support efficient enrollment in this event-driven, global Phase 3 study. Today’s announcement is an exciting step forward in our efforts to address a significant unmet need in cardiovascular care.”
“Experiencing AFib-RVR can be very unsettling. It interrupts daily life and may require urgent medical care. The possibility of providing a self-administered treatment for use upon AFib-RVR onset represents an important area of research for patients with this condition,” said Mellanie True Hills, founder and CEO of StopAfib.org. “The start of the ReVeRA-301 study is an exciting milestone for the AFib patient community. We look forward to the knowledge this research may bring us as investigators evaluate a potential new treatment approach.”
August 21, 2026 
