FDA sends 'refusal-to-file' to Moderna over new flu vaccine

Moderna has developed a new flu vaccine, however, what’s the problem they are facing?

The U.S. Food and Drug Administration is refusing to consider Moderna´s application for the vaccine made with Nobel Prize-winning mRNA technology.

This decision points towards the increased scrutiny of vaccines by the FDA, operating under Health Secretary Robert F. Kennedy Jr., particularly those using mRNA technology, which he has criticized before and after becoming the nation´s top health official.

Moderna received what´s called a "refusal-to-file" letter from the FDA that objected to how it conducted a 40,000-person clinical trial comparing its new vaccine to one of the standard flu shots used today.

That trial concluded the new vaccine was somewhat more effective in adults 50 and older than that standard shot.

The letter from FDA vaccine director Dr. Vinay Prasad said the agency doesn´t consider the application to contain an "adequate and well-controlled trial" because it didn´t compare the new shot to "the best-available standard of care in the United States at the time of the study."

Prasad´s letter also pointed to some advice FDA officials gave Moderna in 2024, under the Biden administration, which Moderna didn´t follow.

According to Moderna, that feedback said it was acceptable to use the standard-dose flu shot the company had chosen - but that another brand specifically recommended for seniors would be preferred for anyone 65 and older in the study. Still, Moderna said, the FDA did agree to let the study proceed as originally planned.

The FDA "did not identify any safety or efficacy concerns with our product" and "does not further our shared goal of enhancing America´s leadership in developing innovative medicines," Moderna CEO Stephane Bancel said in a statement.

It´s rare that FDA refuses to file an application, particularly for a new vaccine, which requires companies and FDA staff to engage in months or years of discussions.

Moderna has requested an urgent meeting with FDA, and revealed that it has applied for the vaccine´s approval in Europe, Canada and Australia.