Milestone Pharmaceuticals Advances Etripamil Nasal Spray Toward EU Approval For First At-Home PSVT Treatment

Milestone® Pharmaceuticals Inc., a biopharmaceutical company focused on innovative cardiovascular therapies, announced that the European Medicines Agency (EMA) has accepted its Marketing Authorization Application (MAA) for etripamil nasal spray, an investigational therapy designed to enable rapid, patient-administered treatment of paroxysmal supraventricular tachycardia (PSVT) outside of healthcare settings.

Etripamil, which carries the conditionally approved European brand name TACHYMIST™, is a novel calcium channel blocker delivered intranasally for on-demand use by patients experiencing PSVT episodes. If approved, it would represent the first self-administered, non-invasive treatment option for PSVT in the out-of-hospital setting. A regulatory decision from the EMA is expected in the first quarter of 2027.

The MAA is supported by a comprehensive clinical development program involving more than 1,800 participants and over 2,000 PSVT episodes. This includes results from the Phase 3 RAPID trial, a global, randomized, double-blind study comparing etripamil with placebo, which was published in The Lancet in 2023.

“Following guidance from the EMA, this MAA incorporates the global clinical data package that supported the U.S. Food and Drug Administration approval of etripamil for the treatment of PSVT,” said Joseph Oliveto, President and Chief Executive Officer of Milestone Pharmaceuticals. “TACHYMIST could become the first approved patient self-administered therapy representing a meaningful step forward in patient care for the approximately two million people suffering from PSVT in Europe.”

In clinical studies, etripamil demonstrated rapid and clinically meaningful conversion of symptomatic PSVT to sinus rhythm. Patients treated with etripamil were twice as likely to convert to sinus rhythm and did so more than three times faster than those receiving placebo. In the RAPID trial, 64% of participants who self-administered etripamil (N=99) achieved conversion within 30 minutes, compared with 31% in the placebo group (N=85) (hazard ratio 2.62; p<0.001). By one hour, 73% of etripamil-treated patients had converted. Median time to conversion was 17 minutes with etripamil versus 54 minutes with placebo.

Etripamil demonstrated a consistent safety and efficacy profile across all subgroups, including patients receiving background beta blockers or calcium channel blockers. The most common adverse events, reported in ≥5% of participants, were mild to moderate and transient, including nasal discomfort, congestion, rhinorrhea, throat irritation, and epistaxis. Fewer than 2% of patients discontinued treatment due to adverse events.