Milestone Wins FDA Approval For First Self-Use Nasal Spray For Sudden Fast Heartbeats

On Friday, the U.S. Food and Drug Administration (FDA) approved Milestone Pharmaceuticals Inc.’s (NASDAQ:MIST) first commercial product, Cardamyst (etripamil) nasal spray.

The approval covers the conversion of acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm in adults.

Cardamyst is expected to be available in retail pharmacies in the first quarter of 2026.

Also Read: Why Is Milestone Pharmaceuticals Stock Plunging On Friday?

First New Treatment Option In Decades

The approval marks Cardamyst as the first FDA-approved treatment in over 30 years for more than 2 million Americans with PSVT.

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.

PSVT is a type of arrhythmia where the heart’s upper chambers beat very fast in sudden, brief episodes, starting and stopping abruptly due to a heart’s electrical “short circuit,” causing palpitations, dizziness, shortness of breath, and chest pain.

Clinical Trial Data And Efficacy

The FDA approval of Cardamyst is supported by a clinical trial program based on safety data from more than 1,800 participants and more than 2,000 episodes of PSVT.

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).

At one hour, the benefit was demonstrated in 73% of participants. In addition, significant reductions in time to conversion in those who took Cardamyst were evident early and durable, with a median time to conversion of 17 minutes for those treated with Cardamyst vs. 54 minutes for those treated with placebo.

MIST Price Action: Milestone Pharmaceuticals shares were up 30.73% at $3.15 during premarket trading on Friday. The stock is trading at a new 52-week high, according to Benzinga Pro data.

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