By VETTAPHARMA reporter: Moderna, Inc. (NASDAQ: MRNA) announced that the U.S. Food and Drug Administration (FDA) has declined to initiate a review of the company’s Biologics License Application (BLA) for its investigational seasonal influenza vaccine candidate, mRNA-1010, issuing a Refusal-to-File (RTF) letter. The FDA decision is based on concerns over the choice of comparator vaccine used in the Phase 3 trial rather than any safety or efficacy issues with the vaccine candidate itself.
The FDA’s Center for Biologics Evaluation and Research (CBER) determined that the Phase 3 study’s use of a licensed standard-dose seasonal influenza vaccine as the comparator did not reflect the “best-available standard of care,” and therefore did not meet the requirements for an “adequate and well-controlled” study under regulatory standards. This RTF letter effectively pauses the regulatory review in the U.S. until Moderna engages further with regulators.
Moderna has said the decision appears inconsistent with prior written communications from CBER, which had previously indicated acceptance of the trial design. The company has requested a Type A meeting with the FDA to clarify next steps and assess how to move forward with the regulatory submission.
Moderna’s mRNA-1010 vaccine candidate was evaluated in Phase 3 studies involving more than 43,800 participants, with both studies meeting all pre-specified primary endpoints and demonstrating statistical superiority versus their respective comparators — meeting targeted efficacy goals. Despite these results, the RTF decision focuses solely on regulatory trial design criteria rather than safety or efficacy shortcomings.
While U.S. regulatory review is on hold, Moderna has said mRNA-1010 continues to advance through regulatory reviews in international markets, including submissions in the European Union, Canada, and Australia, where review outcomes could occur in late 2026 or early 2027.
Source credit:
- Moderna, Inc. (2026, February 10). Moderna receives refusal-to-file letter from the U.S. Food and Drug Administration for its investigational seasonal influenza vaccine, mRNA-1010 [Press release summary]. Click here
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