FDA refuses to file Moderna's mRNA flu vaccine application over its comparator choice

The FDA's vaccine center issued a refusal-to-file letter for mRNA-1010, Moderna's seasonal flu vaccine, even though Moderna had used a priority review voucher. The only reason given was the use of a licensed standard-dose flu shot as the comparator, which the letter said did not reflect the best available standard of care. Moderna disputed that reasoning, asked for a Type A meeting and said it did not expect any effect on 2026 guidance.

• Refusal-to-file issued for mRNA-1010 despite a priority review voucher
• Sole stated reason: licensed standard-dose flu vaccine used as comparator
• Letter signed by CBER Director Vinay Prasad
• Moderna requested a Type A meeting and does not expect an impact on 2026 guidance