Core Insights - Milestone Pharmaceuticals announced consistent efficacy and safety findings for etripamil nasal spray in managing paroxysmal supraventricular tachycardia (PSVT) across multiple clinical trials [1][3][7] - The data will be presented at the American Heart Association Scientific Sessions 2025, highlighting the potential for self-administration of etripamil to improve patient management of PSVT [1][3] Study Findings - Etripamil demonstrated a median time to conversion of symptomatic PSVT episodes of 18.5 minutes, with a conversion rate of 59.6% by 30 minutes and 63.2% to 75.1% by 60 minutes post-administration [7] - Safety data indicated a low rate of test-dose failures at 1.4% and predominantly mild, transient adverse events localized to the nasal site [7] Product Information - Etripamil is a novel calcium channel blocker nasal spray designed for self-administration, aiming to provide rapid response therapy for PSVT and atrial fibrillation with rapid ventricular response (AFib-RVR) [6][9] - The New Drug Application (NDA) for etripamil, branded as CARDAMYST, is currently under evaluation by the U.S. FDA, with a target decision date set for December 13, 2025 [5][9] Company Overview - Milestone Pharmaceuticals focuses on developing innovative cardiovascular medicines, with etripamil being its lead investigational product aimed at improving the management of heart conditions like PSVT [1][9]

Core Points - The FDA has accepted Milestone Pharmaceuticals' response to the Complete Response Letter (CRL) for CARDAMYST™ (etripamil) nasal spray, with a new PDUFA target action date set for December 13, 2025 [1][5] - Milestone has extended its $75 million Royalty Purchase Agreement with RTW Investments until December 31, 2025, to support the planned launch of CARDAMYST following FDA approval [2][4] FDA Review and Response - The FDA's acceptance of the response to the CRL is a significant milestone for CARDAMYST, and the company is optimistic about a potential approval decision later this year [3] - Milestone's response to the CRL included results from additional in-vitro studies and a plan to transfer manufacturing duties to vendors with recent FDA inspection history [5][6] Royalty Purchase Agreement - The Royalty Purchase Agreement allows RTW to purchase tiered royalty payments on etripamil's annual net product sales in exchange for a $75 million purchase price, contingent on FDA approval by December 31, 2025 [4] - The amendment to the agreement reflects RTW's ongoing commitment to Milestone and provides a future funding source for the company [2][3] Product Overview - Etripamil is a novel calcium channel blocker nasal spray designed for self-administration to treat paroxysmal supraventricular tachycardia (PSVT) and atrial fibrillation with rapid ventricular response (AFib-RVR) [7][9] - If approved, CARDAMYST™ aims to offer a new treatment option for patients, allowing for on-demand care and self-management [7][9] Clinical Development - Etripamil has completed a Phase 3 clinical program for PSVT and a Phase 2 trial for AFib-RVR, indicating a robust clinical development pathway [8]