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[2][11] - The first issue involves nitrosamine impurities, with the FDA requesting additional data based on new draft guidance issued after MIST's NDA submission [3] - The second issue relates to a facility inspection involved in the drug's release testing, which underwent a change in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]