Milestone Pharmaceuticals shares surge 22.30% after-hours as CARDAMYST added to Express Scripts commercial national formularies.

Milestone Pharmaceuticals surged 22.30% in after-hours trading following the announcement that its FDA-approved drug, CARDAMYST™ (etripamil) nasal spray, was added to Express Scripts’ commercial national formularies, effective March 27, 2026. This inclusion significantly enhances market access for the first and only self-administered nasal spray treatment for acute episodes of paroxysmal supraventricular tachycardia (PSVT) in adults. The decision marks the first contracted formulary acceptance by a major payor and reflects progress in Milestone’s commercialization strategy, with the company anticipating broader coverage as discussions with other insurers continue.