The US Food and Drug Administration (FDA) has approved Milestone Pharmaceuticals’ Cardamyst (etripamil), the first self-administered nasal spray for adults with paroxysmal supraventricular tachycardia (PSVT).
The rapid-acting treatment is designed to allow patients to manage acute symptomatic episodes outside of emergency healthcare settings.
PSVT causes sudden, unpredictable episodes of rapid heart rate, often leading to severe symptoms and disruptive emergency department visits. Cardamyst, a calcium channel blocker nasal spray, enables patients to self-administer medication at the onset of symptoms, aiming to restore normal sinus rhythm quickly.
“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 CEO of Milestone Pharmaceuticals.
Clinical Trial Efficacy and Safety
The FDA approval is supported by data from more than 1,800 participants across clinical trials, including the Phase III RAPID study (NCT03464019). In the trial, 64% of participants who used Cardamyst converted to normal rhythm within 30 minutes, compared to 31% on placebo. The median time to conversion was 17 minutes versus 54 minutes for placebo.
The safety profile was consistent across subgroups. The most common side effects were mild-to-moderate and transient, including nasal discomfort, congestion, runny nose, throat irritation, and nosebleed. Less than 2% of participants discontinued treatment due to adverse events.
Commercial Launch and Future Development
Milestone expects Cardamyst to be available in US retail pharmacies in the first quarter of 2026. The company is well-capitalized for launch, with $82.6 million in cash and short-term investments as of September 30, 2025, and an anticipated $75 million from a royalty financing agreement triggered by this FDA approval.
Looking ahead, Milestone plans to advance etripamil into a Phase III program for atrial fibrillation with rapid ventricular rate (AFib-RVR), leveraging an sNDA pathway based on the existing approval.
