The U.S. Food and Drug Administration (FDA) has granted approval to Milestone Pharmaceuticals Inc. for its first commercial product, Cardamyst (etripamil) nasal spray. This innovative treatment is intended for adults experiencing acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT). The nasal spray is expected to become available in retail pharmacies by the first quarter of 2026.
This approval marks a significant milestone, as Cardamyst is the first new treatment option for PSVT in over 30 years, providing hope for more than 2 million Americans affected by this condition. PSVT is characterized by rapid heartbeats that originate from the heart’s upper chambers, often leading to symptoms such as palpitations, dizziness, shortness of breath, and chest pain. The condition arises from electrical disturbances in the heart, which can trigger sudden, brief episodes.
Clinical Trial Success and Efficacy
The FDA’s approval of Cardamyst is supported by a comprehensive clinical trial program involving safety data from over 1,800 participants and more than 2,000 episodes of PSVT. Notably, findings from these studies indicate that participants using Cardamyst were twice as likely to convert symptomatic PSVT to sinus rhythm compared to those receiving a placebo, and achieved this result more than three times faster.
In the RAPID trial, which served as a pivotal study, 64% of participants who self-administered Cardamyst converted from supraventricular tachycardia (SVT) to sinus rhythm within 30 minutes, compared to just 31% of participants on placebo. The efficacy of Cardamyst continued to be evident; after one hour, 73% of those treated with the nasal spray experienced conversion, demonstrating significant reductions in time to conversion. Specifically, the median time for conversion was 17 minutes for Cardamyst users, compared to 54 minutes for those on placebo.
Market Reaction and Future Outlook
Following the announcement of the FDA approval, shares of Milestone Pharmaceuticals saw a notable increase, rising 30.73% to $3.15 during premarket trading on the day of the news. This surge in stock price marks a new 52-week high for the company, reflecting investor optimism regarding the potential impact of Cardamyst on the market.
As Milestone Pharmaceuticals prepares for the launch of Cardamyst, the company is poised to address an unmet need in the treatment of PSVT. The introduction of this novel and rapid-acting calcium channel blocker represents a significant advancement in managing this often debilitating condition. With its expected availability in early 2026, Cardamyst could change the lives of many who suffer from PSVT, providing a much-needed option for symptom relief.
