Highlights 

  • Combined analysis demonstrates consistent efficacy and safety across multiple PSVT studies. 
  • Data from 622 patients show rapid episode conversion following self-administered etripamil. 
  • FDA review of CARDAMYST ongoing, with decision expected by December 2025. 

Milestone Pharmaceuticals Inc.NASDAQ:MISTannounced that it will present new clinical data from its investigational etripamil nasal spray program for paroxysmal supraventricular tachycardia at the American Heart Association Scientific Sessions 2025 in New Orleans, Louisiana. 

Key Findings from Pooled Analysis 

The pooled data set comprised 622 patients across multiple international clinical trials. The findings showed that etripamil nasal spray provided consistent efficacy in converting symptomatic PSVT episodes to sinus rhythm across various trial phases, designs, and geographies. 

  • Median time to conversion: 18.5 minutes (95% CI: 15.7–21.0 minutes). 
  • Kaplan-Meier estimate for conversion: 59.6% within 30 minutes (range: 53.6%–64.3%), and 63.2%–75.1% within 60 minutes of dosing. 
  • Safety profile: Based on data from over 1,050 etripamil-treated patients, adverse events were primarily mild, transient, and localized to the nasal site. 
  • Test-dose failure rate: 1.4% among 1,100 patients administered etripamil in sinus rhythm, indicating consistent tolerability. 

Management Commentary 

“These results show the consistent efficacy, with onset soon after self-administration, and safety of etripamil nasal spray across a wide range of studies and patient populations,” said David Bharucha, M.D., Ph.D., FACC, Chief Medical Officer of Milestone. “The potential for patients to self-administer etripamil and achieve rapid termination of symptomatic PSVT episodes would represent a meaningful advance in the management of PSVT, a condition that frequently leads to emergency room visits and causes significant burden for patients.” 

Regulatory Update and Product Overview 

A New Drug Application for CARDAMYST™ (etripamil nasal spray) is currently under review by the U.S. Food and Drug Administration, with a Prescription Drug User Fee Act target date of December 13, 2025. 

Etripamil is an investigational calcium channel blocker nasal spray designed for self-administration to manage acute PSVT and atrial fibrillation with rapid ventricular response (AFib-RVR). The therapy is intended as a rapid-response treatment that can be used by patients without the need for immediate clinical intervention. 

About Milestone Pharmaceuticals 

Milestone Pharmaceuticals Inc. is a biopharmaceutical company focused on developing and commercializing cardiovascular treatments for specific arrhythmias. The company’s lead investigational product, etripamil, has completed its Phase 3 program for PSVT and is under evaluation in a Phase 2 study for AFib-RVR. Further information is available on the company’s official website. 

About Tobevibart and Elebsiran 

Tobevibart is an investigational monoclonal antibody that targets the hepatitis B surface antigen. Developed through Vir’s antibody discovery platform, it is designed to block viral entry into hepatocytes and lower circulating viral particles. 

Elebsiran, developed by Alnylam Pharmaceuticals, Inc., is an investigational small interfering RNA that silences hepatitis B virus RNA transcripts, thereby reducing HBsAg production. 

About Vir Biotechnology, Inc. 

Vir Biotechnology, Inc. is a clinical-stage biopharmaceutical company focused on developing transformative medicines for serious infectious diseases and cancer.