FDA Rejects Moderna’s mRNA Flu Vaccine Application, Company Reports

The US Food and Drug Administration (FDA) has rejected Moderna’s application for its mRNA seasonal flu vaccine. This decision comes as a setback for Moderna, which had been seeking approval for its first mRNA-based flu vaccine.

FDA’s Reasons for Rejection

Moderna disclosed that the FDA found the application lacking in an “adequate and well-controlled” clinical trial. According to a letter from the FDA, the control arm of the study did not represent the “best-available standard of care in the United States” at the time. Importantly, the FDA did not cite any safety or efficacy concerns regarding the vaccine.

Moderna’s Response

Dr. Stephen Hoge, president of Moderna, expressed frustration with the FDA’s decision. He noted that at no point did the FDA indicate that the clinical trial design was inadequate. Following this rejection, Moderna has requested a meeting with FDA officials to clarify the next steps.

Clinical Trial Details

• The clinical trial involved 40,700 participants.
• Moderna used the standard-dose seasonal flu vaccine, Fluarix, as a comparator.
• The FDA had previously agreed with this trial design in April 2024.
• Data comparing Moderna’s vaccine to a high-dose flu vaccine was also included.

Additionally, in discussions leading up to the application, the FDA indicated it would review the filing. However, the latest communication cited potential significant issues with the data.

Background on the mRNA Technology

Moderna is part of a select group of manufacturers in the US that produce approved Covid-19 vaccines, alongside Pfizer and Novavax. Both Moderna and Pfizer rely on mRNA technology, which has shown significant promise. The rapid development of mRNA vaccines during the Covid-19 pandemic was a notable achievement.

Future Prospects for Moderna

Despite the setback in the US, Moderna remains optimistic about its mRNA flu vaccine and the potential for a combination vaccine that targets both flu and Covid-19. Dr. Hoge indicated that approval in Europe may arrive soon, marking a significant milestone for the company.

The hope for mRNA technology in seasonal flu vaccines lies in its capacity to enhance efficacy. This technology allows for faster vaccine production, improving the chances of aligning with circulating strains during flu season.

As Moderna waits for guidance from the FDA, the company continues to pursue the development of its combination flu and Covid-19 mRNA vaccine in international markets.