The U.S. Food and Drug Administration (FDA) has issued a refusal-to-file (RTF) letter regarding Moderna’s next-generation mRNA flu vaccine (mRNA-1010), prompting a sharp response from the biotechnology firm.
The FDA’s rejection centered on the design of Moderna’s Phase 3 trial, specifically criticizing the control arm for not utilizing the “best-available standard of care.” The agency contended that the use of a licensed standard-dose seasonal flu vaccine as a comparator was insufficient. In a strongly worded statement, Moderna CEO Stéphane Bancel argued that federal regulations do not stipulate such a requirement and noted that the trial protocol had been previously discussed and agreed upon with the FDA’s Center for Biologics Evaluation and Research (CBER).
This regulatory hurdle emerges amid a shifting landscape for mRNA technology in the United States:
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Strategic Shift: Moderna is currently reallocating its R&D priorities toward oncology in response to the evolving vaccine market.
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Policy Headwinds: Federal funding for mRNA vaccine development has seen abrupt terminations recently, following public skepticism from high-ranking health officials regarding the platform.
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Global Review: Despite the U.S. setback, the vaccine remains under regulatory review in the European Union, Canada, and Australia, with no changes expected to the company’s 2026 financial guidance.
In an unusual move, Moderna published the RTF letter in full and has requested a meeting with the FDA to determine a path forward.