FDA reverses course, will review Moderna's mRNA flu vaccine candidate

The Food and Drug Administration (FDA) has backtracked its initial decision last week of refusing to review Moderna’s mRNA flu vaccine candidate after holding a high-priority meeting with the company.

Last week, the FDA said it refused to file Moderna’s application over regulatory issues. The company maintained that the refusal had nothing to do with the safety and efficacy of its vaccine candidate. On Wednesday, Moderna broke the news in a press release that the FDA had accepted its application for review following a high-priority, Type A meeting with the agency.

“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,” said the company.

Health and Human Services (HHS) spokesperson Andrew Nixon said “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.”

Nixon claimed Moderna exposed older trial participants to “substandard” care during the trial, though the company said the regulators had reviewed and cleared the design of the trial more than a year ago.

“As authorized under [Prescription Drug User Fee Act] and defined in FDA guidance documents, FDA held a Type A meeting with Moderna. Discussions with the company led to a revised regulatory approach and an amended application, which FDA accepted. FDA will maintain its high standards during review and potential licensure stages as it does with all products,” Nixon said Wednesday when reached by The Hill.

With this development, Moderna noted its flu mRNA candidate has now been accepted for review in the U.S., Canada, Australia and Europe.

Under HHS Secretary Robert F. Kennedy Jr.’s tenure, federal regulators have taken a somewhat hostile stance towards mRNA vaccines, cancelling millions in grant funding last year under the claim that these types of vaccines have been shown to be ineffective.

A federal vaccine advisory committee remade by Kennedy last year also voted to revise guidance for COVID-19 vaccines, the only mRNA shots on the market, to no longer give a blanket recommendation but limit immunization to individual decision-making.

Senior administration officials said last week that Kennedy had no part in Moderna’s request for review being refused, claiming he likely had no idea it was happening until news outlets reported on it.