The U.S. Food and Drug Administration declined to review Moderna’s application for its mRNA‑1010 influenza vaccine, a decision that sent the company’s shares down 8% in extended trading.
In its refusal‑to‑file letter, the FDA said Moderna’s choice to compare the new vaccine to an already licensed standard‑dose seasonal flu shot was the sole reason for not initiating a review. The regulator cited a lack of an “adequate and well‑controlled” study with a comparator arm that does not reflect the best‑available standard of care.
CEO Stephane Bancel noted that the decision did not stem from safety or efficacy concerns, but it does hinder the shared goal of boosting America’s leadership in innovative medicines.
Moderna argued that the letter contradicts earlier communications. The company had agreed with the FDA’s Center for Biologics Evaluation and Research to use an FDA‑approved vaccine as a comparator before starting the trials.
The marketing application for mRNA‑1010 included two late‑stage studies that met their primary endpoints. Last year the company reported the vaccine was 26.6% more effective than an approved annual flu shot from GSK.
Moderna has requested a meeting with regulators to understand the path forward.
This development follows a U.S. overhaul of long‑standing guidance on childhood immunization and a rollback of routine vaccination recommendations for six diseases, including influenza.
Earlier this year, the company said it would not invest in new late‑stage vaccine trials amid growing opposition to immunizations from U.S. officials. It withdrew its application for a flu‑and‑COVID combination vaccine to wait for efficacy data from a late‑stage trial of its influenza vaccine.
The vaccine is currently under review in the EU, Canada, and Australia, with potential approvals expected in late 2026 or early 2027.
For context, current FDA‑approved influenza vaccines include those produced by AstraZeneca and Sanofi.
