Milestone Pharmaceuticals Inc. (Nasdaq: MIST) has announced a significant development in its pursuit to commercialize etripamil nasal spray, a novel therapy for Paroxysmal Supraventricular Tachycardia (PSVT). The United States Patent and Trademark Office (USPTO) has issued a Notice of Allowance for a new Method of Use patent covering etripamil, potentially extending intellectual property protection in the U.S. until July 2042. This patent specifically protects the repeat dose regimen of etripamil, which was evaluated in the Phase 3 RAPID study and is included in the New Drug Application (NDA) for CARDAMYST™ currently under review by the FDA.
Patent Extension and Commercial Strategy
The allowed patent, stemming from U.S. Patent Application No.: 17/865,697, safeguards the method of using a second 70 mg dose of CARDAMYST if PSVT symptoms persist ten minutes after the initial dose. Joseph Oliveto, President and CEO of Milestone Pharmaceuticals, stated, "This added protection will position us to optimize the commercial value of CARDAMYST," emphasizing the company's commitment to innovation in cardiology.
Regulatory and Launch Preparations
Milestone's NDA for CARDAMYST is under review by the FDA, with a Prescription Drug User Fee Act (PDUFA) target date of March 27, 2025. The company is actively advancing commercial preparations to support a potential launch in mid-2025. The FDA has conditionally approved the brand name CARDAMYST for etripamil nasal spray.
Clinical Development and Future Trials
Etripamil, a novel calcium channel blocker nasal spray, is also under clinical development for Atrial Fibrillation with Rapid Ventricular Rate (AFib-RVR). Milestone plans to initiate a Phase 3 trial in H1 2025 to evaluate etripamil in AFib-RVR patients in the at-home setting, using a self-administered, repeat-dose regimen of 70 mg/dose, mirroring the approach used in the successful RAPID trial for PSVT. The study is designed to capture approximately 150 events in patients experiencing symptomatic episodes.
Etripamil: A Patient-Centric Approach
Etripamil is designed as a rapid-response therapy that patients can self-administer, potentially reducing the need for immediate medical oversight. If approved, it would provide healthcare providers with a new option for on-demand care and patient self-management, offering patients greater control over their condition. Milestone will have its first branded product presence at ACC.2025 (American College of Cardiology annual meeting, March 29 to 31, 2025 in Chicago) and the Heart Rhythm Society Annual Meeting (April 24 to 27, 2025 in San Diego), assuming approval on the PDUFA date.
