FDA Accepts Moderna's mRNA Flu Vaccine Application After Regulatory Dispute

The FDA has accepted Moderna's biologics license application for its investigational seasonal influenza vaccine mRNA-1010 and assigned a Prescription Drug User Fee Act (PDUFA) goal date of August 5, 2026. The decision follows a Type A meeting where Moderna proposed a revised regulatory approach after receiving a prior Refusal-to-File (RTF) letter.

To advance the review, Moderna proposed a regulatory pathway based on age, seeking full approval for adults 50 to 64 years of age and accelerated approval for adults 65 and older, along with a post-marketing requirement to conduct an additional study in older adults. Pending review and FDA approval, mRNA-1010 would be available for U.S. adults 50 years of age and older, including adults 65 and older, for the 2026/2027 flu season.

The investigational vaccine demonstrated superior efficacy in a phase 3 trial (NCT05415462) involving more than 40,000 adults 50 years and older compared with a standard licensed influenza vaccine. The FDA's Center for Biologics Evaluation and Research has notified Moderna that its biologics license application for mRNA-1010 will proceed to review.

The earlier refusal stemmed from FDA concerns that Moderna's pivotal study did not compare the vaccine against the highest-dose flu vaccines recommended for older adults, which regulators argued would have better represented the best available standard of care for that population. Moderna countered that the initial study design had been discussed in prior consultations with the FDA and that no safety or efficacy concerns were raised prior to submission.

The CEO stated, "We appreciate the FDA's engagement in a constructive Type A meeting and its agreement to advance our application for review. Pending FDA approval, we look forward to making our flu vaccine available later this year so that America's seniors have access to a new option to protect themselves against flu."

mRNA-1010 has now been accepted for review in the United States, Europe, Canada and Australia with further submissions planned in 2026. Moderna expects the first potential approvals for mRNA-1010 in 2026, subject to various ongoing regulatory reviews.

Following the FDA's acceptance of the application, Moderna's shares gained in premarket trading, reflecting investor optimism about the company's future growth potential, especially after facing pressure from last week's FDA refusal-to-file letter.

This episode has reignited broader debate about the regulatory environment for mRNA-based vaccines, as critics argue that restrictive approaches could slow innovation in next-generation vaccine development. The initial refusal came amid heightened FDA scrutiny of mRNA technologies under current federal leadership, including actions by HHS Secretary Robert F. Kennedy Jr, who has publicly challenged certain aspects of mRNA vaccine policy.