The Food and Drug Administration (FDA) has declined to review Moderna’s application for its mRNA-based influenza vaccine, mRNA-1010, the company announced on Monday. The agency issued a Refusal-to-File (RTF) letter, halting the process despite Moderna utilizing a Priority Review Voucher intended to expedite consideration of the application.
According to the RTF letter, signed by Dr. Vinayak Prasad, director of the FDA’s Center for Biologics Evaluation and Research (CBER), the decision stems from the clinical trial design, specifically the use of a licensed, standard-dose influenza vaccine as a comparator. The FDA argued the study lacked an “adequate and well-controlled” comparator representing the “best-available standard of care,” though existing regulations and guidance do not explicitly mandate such a comparator. The agency stated it had no safety or efficacy concerns with the vaccine itself.
Moderna’s application was based on data from two phase 3 studies involving a total of 43,808 participants. The IGNITE P303 part C trial assessed the vaccine’s performance in adults 65 years and older, comparing it to a high-dose influenza vaccine. P304 evaluated mRNA-1010 against a licensed, inactivated seasonal influenza vaccine in adults aged 50 years and older. Both trials met their primary endpoints and demonstrated statistically significant superiority over their respective comparators, according to Moderna.
The company contends that the P304 efficacy study employed a methodology similar to those used to secure approval for two influenza vaccines currently recommended for older adults in the United States. These approved vaccines also demonstrated statistically superior relative efficacy compared to standard-dose comparators.
Moderna CEO Stéphane Bancel expressed disappointment with the FDA’s decision, stating it “does not further our shared goal of enhancing America’s leadership in developing innovative medicines.” He also noted that CBER had previously indicated, during a pre-phase 3 consultation in April 2024, that using a licensed standard-dose influenza vaccine as a comparator would be acceptable, whereas a vaccine preferentially recommended for those over 65 was suggested. CBER did not raise objections to the study protocol before the trial commenced in September 2024.
Following completion of the phase 3 efficacy trial in August 2025, Moderna held a pre-submission meeting with CBER and received written feedback requesting additional analyses regarding the comparator. The company provided these analyses, including data from a separate phase 3 trial comparing mRNA-1010 with a licensed high-dose influenza vaccine. Moderna asserts that CBER did not signal at any point that it would refuse to review the application.
“It should not be controversial to conduct a comprehensive review of a flu vaccine submission that uses an FDA-approved vaccine as a comparator in a study that was discussed and agreed on with CBER prior to starting,” Bancel said. “We glance forward to engaging with CBER to understand the path forward as quickly as possible so that America’s seniors, and those with underlying conditions, continue to have access to American-made innovations.”
Moderna has requested a Type A meeting with CBER to discuss the RTF letter and clarify the agency’s reasoning. As of Tuesday, February 11, 2026, the FDA has not publicly responded to Moderna’s statement or confirmed the scheduling of a meeting.
