Moderna says US refusing to review mRNA-based flu shot

WASHINGTON

Vaccine manufacturer Moderna said on Feb. 10 the U.S. Food and Drug Administration (FDA) was refusing to review an application for its first mRNA-based flu shot.

The move comes as the current iteration of the FDA has called for a reconsideration of approval procedures for certain vaccines, including for influenza, proposed federal policy changes under President Donald Trump that have triggered widespread alarm among public health and medical professionals.

Moderna, a U.S. company, said the agency's top vaccine regulator, Vinay Prasad, wrote in a letter that Moderna's clinical trial was not "adequate and well-controlled," and had not tested its experimental shot against the best product on the market.

In the large trial Moderna had compared its new vaccine with Fluarix, an approved flu shot from the company GSK.

Moderna said the rejection was "inconsistent with previous written communications" with the FDA branch that regulates biological products, including vaccines, known by the acronym CBER.

Moderna said it had received a Refusal-to-File letter, which would indicate the application did not meet the requirements for substantive review. The company said it had requested a meeting to discuss the decision.

The letter did not identify any safety or efficacy concerns regarding the mRNA vaccine, said Moderna, which added the shot was accepted for review in the European Union, Canada and Australia.

During his first term Trump called mRNA technology a "modern-day miracle."