The Vaccines and Related Biological Products Advisory Committee convenes virtually on June 18 to weigh in on whether Moderna’s MFLUSIVA — the brand name for mRNA-1010, a tetravalent mRNA seasonal influenza vaccine — is safe and effective for adults 50 years of age and older. It would be the first mRNA influenza vaccine ever to reach an FDA advisory panel.
The committee will discuss and make recommendations on Biologics License Application STN 125869/0. VRBPAC’s vote is advisory, not decisive; the agency retains full authority over the final licensing decision. FDA has set a PDUFA goal date of August 5, 2026.
What the panel will weigh
Moderna is pursuing a split-pathway strategy. For adults aged 50 to 64, the company is seeking standard full approval, supported by efficacy data from the pivotal Phase 3 P304 trial. For adults 65 and older — a population at highest risk from influenza complications — Moderna is requesting accelerated approval, supported by immunogenicity bridging from the P303 Part C study.
Phase 3 efficacy snapshot
The P304 trial, published May 6, 2026 in the New England Journal of Medicine (394:1803–1813; DOI: 10.1056/NEJMoa2516491), randomized 40,805 adults aged 50 and older across 11 countries. mRNA-1010 achieved a relative vaccine efficacy of 26.6% (95% CI: 16.7%–35.4%) against PCR-confirmed influenza illness compared with a licensed standard-dose comparator, meeting the protocol’s prespecified superiority criterion. Strain-specific estimates: rVE 29.6% for A/H1N1, 22.2% for A/H3N2, and 29.1% for B/Victoria lineages. In participants 65 and older, rVE was 27.4%. The safety profile was consistent with prior studies; no significant safety concerns were identified.
A rocky regulatory path
On February 3, 2026, FDA’s Center for Biologics Evaluation and Research issued a Refuse-to-File letter citing a single technical concern: the choice of a licensed standard-dose influenza vaccine as the comparator in P304. No safety or efficacy concerns with the vaccine itself were raised.
Following a Type A meeting with regulators, Moderna resubmitted an amended BLA. The agency reversed course, accepted the application, and assigned the August 5 PDUFA date — an unusual outcome that underscored the agency’s view that the underlying data package was scientifically sound.
“Approval would mark a technology milestone: the first mRNA platform vaccine licensed for a pathogen other than SARS-CoV-2.”
Approximately 40,000 to 50,000 Americans die from influenza-associated illness each year. Whether VRBPAC’s recommendation, and any subsequent FDA decision, can move the needle on that burden is the core question hanging over the June 18 session.