US drug regulator declines to review Moderna mRNA flu shot

ANKARA

The US drug regulator has declined to review Moderna’s application for an mRNA influenza vaccine, saying the company’s main late-stage study did not use the most appropriate comparison shot, the company said Tuesday.

The Food and Drug Administration (FDA), the federal agency that evaluates the safety and effectiveness of medicines and vaccines before they can be sold in the US, issued a rare refusal-to-file letter for Moderna’s mRNA-1010 vaccine, saying the company’s late-stage study did not use what regulators described as the “best-available standard of care” as a comparator. Instead, Moderna compared its shot to a licensed standard-dose flu vaccine.

The company said the letter did not raise any safety or efficacy concerns and argued that the decision conflicts with earlier written feedback from regulators.

Moderna said it had discussed the trial design with the FDA before launching its Phase 3 study and later submitted additional analyses, including data comparing the vaccine with a high-dose flu shot in adults 65 and older.

Stephane Bancel, the company’s CEO, said the company has requested a Type A meeting with regulators to clarify what is needed to move forward.

Moderna noted that its application has been accepted for review in the EU, Canada, and Australia.

Moderna’s president, Dr. Stephen Hoge, told CNN that after discussing with the FDA how to run its clinical trial, with no objections raised, the rejection decision was “a complete stunner.”

The rejection was signed by Dr. Vinay Prasad, director of the FDA’s Center for Biologics Evaluation and Research, but also a vocal critic of the US’ COVID-19 response, CNN added. He has claimed that COVID vaccines resulted in the deaths of 10 children, without giving details.

Health and Human Services Department Secretary Robert F. Kennedy Jr, who appointed Prasad, has been a strong critic of vaccines, and critics say he has filled positions within the department and the FDA with other vaccine skeptics.

Last August, the department canceled 22 projects worth about half a billion dollars focused on mRNA vaccine development, claiming that they “fail to protect effectively against upper respiratory infections like COVID and flu.”

Moderna said it does not expect the FDA’s decision to affect its 2026 financial guidance and that potential approvals outside the US could begin in late 2026 or early 2027.