Moderna faced a setback as the U.S. Food and Drug Administration rejected their application for a new flu vaccine utilizing mRNA technology, as announced by the company on Tuesday. The FDA’s refusal stems from concerns raised during a 40,000-person clinical trial comparing Moderna’s vaccine with a standard flu shot. The trial revealed the new vaccine’s slightly superior effectiveness in adults aged 50 and above.
Dr. Vinay Prasad, the FDA’s vaccine director, highlighted that the trial did not adequately compare the new vaccine with the best-available standard flu shot in the U.S. at the time, leading to the issuance of a “refusal-to-file” letter to Moderna. Despite feedback from the FDA advising a different flu shot for participants aged 65 and older, Moderna proceeded with its original plan, prompting the FDA to question the trial’s design.
Moderna, however, emphasized that the FDA did not raise any safety or efficacy concerns regarding their product. CEO Stephane Bancel affirmed the company’s commitment to meeting FDA requirements and shared additional data from a separate trial comparing the new vaccine with a high-dose flu shot for seniors.
The FDA’s refusal to file an application for a new vaccine is uncommon, necessitating further discussions between companies and regulatory authorities. Moderna has requested an urgent meeting with the FDA while simultaneously seeking approval for the vaccine in Europe, Canada, and Australia.
Under Health Secretary Robert F. Kennedy Jr., recent regulatory changes have included modifications to COVID-19 vaccine recommendations, enhanced warnings for mRNA-based COVID vaccines, and reshuffling of FDA advisory panels. Kennedy’s department also revoked over $500 million in funding for mRNA vaccine development last year.
Traditionally, the FDA allows vaccine manufacturers to update flu shots annually based on immune response data rather than lengthy studies on flu incidence and patient outcomes. However, a recent internal memo from Dr. Prasad hinted at a shift in this approach, drawing criticism from former FDA commissioners who denounced the proposed changes.