FDA Reversal on Moderna's mRNA Flu Vaccine Application

The Food and Drug Administration rattled the biotech industry last week when it said it wouldn't even look at Moderna's application to market the first mRNA flu shot. But on Wednesday, the agency reversed course and told Moderna it would review the application with some changes.

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 FDA's reversal, however, didn't reassure health economist Rena Conti at Boston University, who says the Moderna decisions appear to be part of a pattern with the current FDA. "This type of chaotic decision-making is the opposite of what the regulator should be doing to regulate medicines in the U.S.," she said.

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.

Initially, the FDA said it wouldn't review the new shot because the company didn't compare it to a high-dose flu vaccine for older people as part of its main clinical trials.

Moderna said the FDA had agreed to its study design 18 months ago. "The industry depends on clear, transparent rules that are applied consistently in order to make the long-term investments that benefit Americans," Moderna spokesman Chris Ridley wrote in an email to NPR last week.

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."

Health and Human Services Department spokesman Andrew Nixon said in an emailed statement to NPR last week 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, Nixon said in an email to NPR that 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," he said.

Moderna says it agreed to add a confirmatory study in older adults that will use a high-dose flu shot after the mRNA vaccine is on the market, the company confirmed to NPR.

The company says the new vaccine will be ready for the next flu season, pending FDA approval.