FDA Reverses Decision, Agrees to Review Moderna's mRNA Flu Vaccine
The FDA reversed its refusal to review Moderna's mRNA flu vaccine application after the company amended its submission. The agency will now consider full approval for adults 50-64 and accelerated approval for those 65 and older, with a decision expected by August 5, 2026.
The Food and Drug Administration reversed its decision and agreed to review Moderna's application for an mRNA influenza vaccine, the company announced Wednesday. The reversal comes just one week after the agency refused to consider the application, a decision that rattled the biotech industry.
The FDA's Center for Biologics Evaluation and Research accepted the amended submission for mRNA-1010 following a Type A meeting that addressed issues raised in a previous Refusal-to-File letter. The agency assigned a Prescription Drug User Fee Act goal date of August 5, 2026.
Under the revised regulatory approach, the FDA will consider full approval for adults ages 50 to 64 and accelerated approval for adults 65 and older. Moderna agreed to conduct an additional post-marketing study in the older population. If approved, the vaccine would be indicated for U.S. adults age 50 and older.
The initial refusal was based on the design of Moderna's clinical trial. In a letter dated February 3, the agency said Moderna's choice to use licensed standard-dose influenza vaccines, including Fluarix, made by GlaxoSmithKline, in the trial "does not reflect the best-available standard of care," and therefore the trial was not "adequate and well-controlled."
Moderna's Phase 3 trial involved nearly 41,000 adults aged 50 and older. The company said the FDA had agreed to its study design 18 months ago. According to a company statement, Moderna included data from a separate trial comparing its mRNA shot to a high-dose flu vaccine when it submitted the application. "At no time in the pre-submission written feedback or meeting did [the FDA's Center for Biologics Evaluation and Research] indicate that it would refuse to review the file."
FDA scientists had previously suggested that the company use a recommended high-dose flu vaccine in trial participants 65 and older. But the agency ultimately signed off on the trial design with the uniform standard dose, calling it "acceptable." Moderna agreed to add a comparison of a high-dose vaccine to some older participants and provide the FDA with additional analysis.
The decision to refuse the initial application was made by top agency official Vinay Prasad, the head of the FDA's Center for Biologics Evaluation and Research, who personally overruled career scientists in the vaccine center.
A Health and Human Services Department spokesman said in an emailed statement that "the FDA rejected Moderna's application for filing because the company refused to follow very clear FDA guidance from 2024 to test its product in a clinical trial against a CDC-recommended flu vaccine to compare safety and efficacy." On Wednesday, the spokesman said the FDA had a meeting with Moderna, leading the company to amend its application for the experimental shot, which the FDA accepted. "FDA will maintain its high standards during review and potential licensure stages as it does with all products."
FDA Commissioner Marty Makary hinted during a Pharmaceutical Research and Manufacturers of America event on Tuesday that the agency's refuse-to-file letter to Moderna wasn't the end for the company's shot. "That letter, in my mind, is part of the conversation where you'll see a dialogue between the company and the agency, and they can always, after that letter, ask for the more detailed review," he said during the PhRMA Forum in Washington, D.C. "But that's part of the process. That's a conversation."
The company's CEO said in the announcement, "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."
Moderna used its mRNA technology to swiftly create and manufacture its COVID-19 shot during the pandemic. The company is hoping to use that technology to make flu shots, too. Moderna says the total investment in the shot is over a billion dollars, including up to $750 million from Blackstone, an asset management firm.
The company says the new vaccine will be ready for the next flu season, pending FDA approval. The mRNA-1010 application has also been accepted for regulatory review in Europe, Canada and Australia, with additional submissions planned in 2026. The company said it expects potential initial approvals in 2026, subject to the outcome of ongoing regulatory reviews.
Moderna's shares lifted more than 3% following the announcement. The company's stock had dropped 12% after the initial rejection, erasing nearly $2 billion from its market value.