A researcher works in the laboratory at Moderna Inc. headquarters in Cambridge, Massachusetts, United States, Tuesday, March 26, 2024.
Adam Glanzman | Bloomberg | Getty Images
The Food and Drug Administration declined to begin a review of ModernThe demand for an experimental flu vaccine.
The company’s shares fell about 7% after hours Tuesday.
Moderna said the move was inconsistent with previous comments the agency made before submitting the application and beginning phase three trials of the vaccine, called mRNA-1010. The drugmaker said it requested a meeting with the FDA to “understand the path forward.”
Moderna noted that the agency did not identify any specific safety or effectiveness concerns with the vaccine, but instead opposed the study design, although it had previously approved it. The company added that the move would not impact its 2026 financial guidance.
Moderna’s vaccine showed positive phase three data last year, meeting all trial goals. At the time, Moderna said the standalone flu vaccine was key to its efforts to advance a combination vaccine targeting both flu and Covid-19.
The announcement follows sweeping changes to U.S. vaccination policy over the past year under Health and Human Services Secretary Robert F. Kennedy Jr., a prominent vaccine skeptic.
Moderna on Tuesday specifically highlighted the FDA’s top vaccine regulator, Vinay Prasad, who returned to the agency in August after being ousted. Prasad, who heads the agency’s Center for Biologics Evaluation and Research, or CBER, has spoken in favor of strengthening vaccine regulations and recently linked child deaths to Covid shots.
In a letter signed by Prasad on February 3, he said the only reason the FDA refused to review the application was the way the vaccine clinical trial was designed.
The agency specifically took issue with Moderna’s decision to compare its product to an approved standard flu vaccine, arguing that it “does not reflect the best available standard of care.” As a result, the FDA said the study did not meet its definition of an “adequate and well-controlled” trial.
Moderna disputes this reasoning, noting that FDA rules and guidelines do not actually require that trials use the most advanced or highest-dose vaccine as a comparator in clinical studies.
“This decision by CBER, which has not identified any safety or effectiveness concerns with our product, does not advance our shared goal of strengthening American leadership in the development of innovative medicines,” Stéphane Bancel, CEO of Moderna, said in a statement. “It should not be controversial to conduct a full review of an influenza vaccine submission using an FDA-approved vaccine as a comparator in a study that was discussed and agreed upon with CBER before commencing.”
Moderna said it expects the first approval of its flu vaccine to occur in late 2026 or late 2027, pending regulatory reviews in the United States, Europe, Canada and Australia.
The FDA said it does not comment on regulatory communications to individual sponsors.