The FDA issued a refusal-to-file letter for Moderna’s mRNA influenza application, citing concerns over the vaccine’s pivotal trial design rather than explicit safety or efficacy problems. Moderna said the agency objected to the choice of comparator vaccine in its Phase 3 study and has requested a meeting to clarify the path forward. The company noted its shot, mRNA-1010, met primary endpoints in Phase 3 and that the agency did not raise specific safety concerns. Moderna’s CEO and the company publicly criticized the agency’s rationale as inconsistent with prior feedback. The decision follows broader policy shifts at HHS and changes at the FDA’s CBER leadership. Moderna reiterated guidance that the letter will not affect its 2026 financial outlook while it seeks resolution with regulators.