Overview
- Moderna disclosed it received an FDA refusal-to-file letter dated Feb. 3 for mRNA-1010, preventing the agency from starting a substantive review.
- The letter, signed by CBER director Dr. Vinay Prasad, cited the choice of a standard-dose comparator rather than the best-available standard of care as the sole reason.
- Moderna says the FDA did not raise safety or efficacy concerns and argues the decision contradicts prior written and verbal feedback in 2024–2025 on the trial design.
- The late-stage program enrolled roughly 40,000 participants and previously showed the shot was 26.6% more effective than a licensed standard-dose flu vaccine.
- The company has requested an urgent FDA meeting and notes its applications are under review in Europe, Canada and Australia, as shares fell sharply on the news.