First FDA approved treatment in 30+ years for more than 2 million Americans with PSVT Novel nasal spray designed to rapidly resolve episodes of PSVT and restore sinus rhythmFDA approval in PSVT enables development of AFib-RVR under sNDA pathwayMilestone well-capitalized to launch and commercialize CARDAMYST with existing capital and royalty financingConference call and webcast December 15, 8:00 a.m. ET MONTREAL and CHARLOTTE, N.C., Dec. 12, 2025 (GLOBE NEWSWIRE) — Milestone® Pharmaceuticals Inc.  (Nasdaq: MIST) today announced that the U.S. Food and Drug Administration (FDA) approved its first commercial product, CARDAMYST™ (etripamil) nasal spray, a prescription medication for the conversion of acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm in adults. This approval marks the first time that more than two million Americans with PSVT will have a rapid-acting treatment option they can self-administer outside the emergency department or other healthcare setting. CARDAMYST is expected to be available in retail pharmacies in the first quarter of 2026. CARDAMYST nasal spray is a novel and rapid-acting calcium channel blocker delivered when needed to treat often highly symptomatic and unpredictable episodes of PSVT. With CARDAMYST, adults with PSVT can be prepared wherever and whenever episodes occur, providing them with active management and a greater sense of control of their condition. “CARDAMYST is a novel at-the-ready treatment option that addresses the unpredictable impact of PSVT by offering patients the freedom to manage episodes anytime and anywhere,” said Joseph Oliveto, President and Chief Executive Officer of Milestone Pharmaceuticals. “The FDA approval of CARDAMYST is a watershed moment for Milestone and a gratifying event for our team members, patients, clinical investigators, and health care providers who participated in the development program, all of whom I sincerely thank for their dedication, counsel, and collaboration toward this important achievement.” “Some people with PSVT have endured years of anxiety, fearing their next episode and the stress and disruption of emergency department visits,” said James Ip, M.D., FACC, FHRS, an etripamil investigator. “CARDAMYST will give many of them the ability to administer a medication themselves that can quickly stop their PSVT episode and potentially avoid a hospital trip or a call to emergency services.” CARDAMYST Clinical Data The FDA approval of CARDAMYST is supported by a robust clinical trial program based on safety data from more than 1,800 participants and more than 2,000 episodes of PSVT. This includes the successful Phase 3 RAPID trial, a global, randomized, double-blind comparison of CARDAMYST vs. placebo, published in The Lancet in 2023. In clinical studies, participants using CARDAMYST were two times more likely to convert symptomatic PSVT to sinus rhythm and did so more than three times faster compared with placebo. The RAPID trial achieved its primary endpoint with 64% of those who self-administered CARDAMYST (N=99) converting from supraventricular tachycardia (SVT) to sinus rhythm within 30 minutes compared to 31% on placebo (N=85) (HR = 2.62; p