The Food and Drug Administration (FDA) has reversed its recent decision and will now review Moderna’s application for its mRNA-based influenza vaccine. This comes after a surprising initial refusal to consider the application, a move that raised concerns among vaccine makers and investors. The FDA now expects to make a decision on the vaccine by .
The initial rejection, revealed last week, was attributed to a disagreement over the comparator vaccine used in Moderna’s Phase 3 clinical trial. According to a letter from Vinay Prasad, a political appointee serving as the Trump administration’s top vaccine regulator, the choice of licensed standard-dose influenza vaccines, such as Fluarix made by GlaxoSmithKline, “does not reflect the best-available standard of care.” Prasad argued this rendered the trial “not adequate and well-controlled.”
Moderna initiated a formal (Type A) meeting with the FDA to address these concerns and proposed a change to the regulatory pathways for the application. Following this meeting, the FDA agreed to review the application. “We appreciate the FDA’s engagement in a constructive Type A meeting and its agreement to advance our application for review,” said Stéphane Bancel, Moderna’s CEO, in a statement released on .
The vaccine, known as mRNA-1010, was tested in a Phase 3 trial involving nearly 41,000 adults aged 50 and older. The FDA’s initial concern centered on the control group receiving currently licensed influenza vaccines, rather than what Prasad considered a higher standard of care. The agency suggested that providing a higher-strength vaccine to older participants in the control arm would have been preferable.
The reversal highlights a period of volatility at the FDA, which has experienced departures of top career officials under Health Secretary Robert F. Kennedy Jr. The situation also underscores the potential for political influence on regulatory decisions, as the initial rejection was reportedly made by Prasad despite disagreement from agency scientists and a career official.
The FDA is now considering a revised application seeking full approval of the mRNA flu vaccine for adults aged 50 to 64, and accelerated approval for those 65 and above. Accelerated approval for the older age group would require a post-marketing confirmatory study to gain regular approval. This tiered approach suggests a higher bar for demonstrating efficacy in seniors, a population particularly vulnerable to severe complications from influenza.
The potential approval of Moderna’s mRNA flu vaccine would represent a significant advancement in influenza prevention. MRNA technology allows for faster development and production compared to traditional vaccine manufacturing methods. This could be particularly valuable in responding to evolving influenza strains and potential pandemics.
The FDA’s initial refusal to file the application and subsequent reconsideration sparked considerable debate within the pharmaceutical industry. Moderna publicly disclosed the FDA’s letter, a move that is unusual and reflects the high stakes involved. The company had previously stated that the FDA had approved the trial design as adequate when the study began 18 months prior to the rejection.
During a press briefing, senior FDA officials defended the agency’s position, stating that Moderna was potentially putting patients at risk by not utilizing a higher-strength vaccine in the control arm of the trial. FDA Commissioner Dr. Marty Makary also addressed the situation publicly, defending the agency’s actions.
The outcome of the FDA’s review will have implications not only for Moderna but also for the broader development of mRNA vaccines. A successful approval could pave the way for other mRNA-based vaccines targeting various infectious diseases. The agency’s decision is being closely watched by the pharmaceutical industry and public health officials alike.
While the FDA’s reversal is a positive step for Moderna, the agency’s insistence on a higher standard for seniors suggests a cautious approach. The need for a post-marketing confirmatory study for those aged 65 and above indicates that further evidence is required to establish the vaccine’s long-term efficacy and safety in this vulnerable population.
