Core Viewpoint - Milestone Pharmaceuticals has submitted a response to the FDA's Complete Response Letter regarding its New Drug Application for CARDAMYST™ (etripamil) nasal spray, aimed at treating acute episodes of paroxysmal supraventricular tachycardia (PSVT) in adults, with a new PDUFA date expected within the year [1][2]. Company Overview - Milestone Pharmaceuticals Inc. is a biopharmaceutical company focused on developing innovative cardiovascular solutions to enhance the lives of individuals with complex heart conditions [4]. - The company emphasizes understanding unmet patient needs and improving patient experiences through new treatment approaches that allow for self-management [4]. Product Information - Etripamil is the lead investigational product of Milestone, designed as a novel calcium channel blocker nasal spray for the rapid treatment of symptomatic episodes of PSVT and atrial fibrillation with rapid ventricular response (AFib-RVR) [3]. - If approved, CARDAMYST™ will be the first self-administered therapy for the rapid termination of PSVT episodes, providing patients with greater control over their condition [2][3]. Regulatory Interaction - A recent Type A meeting with the FDA was deemed productive, providing necessary guidance for the resubmission of the NDA [2]. - The FDA's acceptance of the response and the determination of the new PDUFA date will occur within the next thirty days, with a review period expected to be between 2 to 6 months from resubmission [1].

Core Viewpoint - Milestone Pharmaceuticals has submitted a response to the FDA's Complete Response Letter regarding its New Drug Application for CARDAMYST™ (etripamil) nasal spray, aimed at treating acute episodes of paroxysmal supraventricular tachycardia (PSVT) in adults, with a new PDUFA date expected within the year [1][2]. Group 1: Company Overview - Milestone Pharmaceuticals Inc. is a biopharmaceutical company focused on developing innovative cardiovascular solutions to enhance the lives of individuals with complex heart conditions [4]. - The company's lead investigational product, etripamil, is a novel calcium channel blocker nasal spray designed for self-administration, allowing patients to manage symptomatic episodes of PSVT and AFib-RVR without immediate medical supervision [3][4]. Group 2: Product Development - Etripamil is under clinical development for frequent and symptomatic episodes of PSVT and AFib-RVR, with a robust clinical trial program that includes a completed Phase 3 program for PSVT and a Phase 2 trial for AFib-RVR [3]. - If approved, CARDAMYST™ will be the first self-administered therapy for the rapid termination of PSVT episodes, providing patients with greater control over their condition [2][3]. Group 3: Regulatory Interaction - The recent Type A meeting with the FDA was deemed productive, providing necessary guidance for the resubmission of the NDA [2]. - The acceptance of the response and the corresponding PDUFA date will be determined within the next thirty days, with the review expected to take between 2 to 6 months from resubmission [1].

Core Viewpoint - Milestone Pharmaceuticals (MIST) received a Complete Response Letter (CRL) from the FDA for its New Drug Application (NDA) for CARDAMYST (etripamil) nasal spray, intended for treating paroxysmal supraventricular tachycardia (PSVT) [1][2] Regulatory Issues - The CRL does not raise concerns about the clinical safety or efficacy of etripamil but highlights two Chemistry, Manufacturing, and Controls (CMC) issues that need to be resolved before approval [2][11] - The first issue involves nitrosamine impurities, with the FDA requesting additional data based on new draft guidance issued after MIST's NDA submission [3] - The second issue relates to a facility inspection involved in the drug's release testing, which underwent a change in ownership during the NDA review, necessitating a compliance evaluation [4] Market Reaction - Following the CRL issuance, MIST's shares fell by 66.2%, with a year-to-date loss of 67.8%, contrasting with the industry's growth of 2.2% [2][7] - Analysts remain cautiously optimistic about the drug's prospects, suggesting a potential commercial launch in 2026, delayed from the original expectation of mid-2025 [8][11] Company Response and Financial Position - MIST has expressed its intent to request a Type A meeting with the FDA to clarify the path forward and is committed to addressing the outstanding issues [9] - As of December 31, 2024, MIST reported $69.7 million in cash and short-term investments, providing a runway for ongoing development efforts, although additional capital may be needed if delays continue [10] Investor Perspective - The CRL is viewed as a temporary obstacle rather than a fundamental rejection of CARDAMYST's therapeutic potential, with the absence of clinical concerns being a positive indicator for eventual approval [11]