Moderna Stock Drops After FDA Declines Review of mRNA Flu Vaccine

Moderna Inc. (NASDAQ: MRNA) shares declined sharply in after-hours trading on Tuesday after the biotechnology company disclosed that the U.S. Food and Drug Administration (FDA) has declined to review its influenza vaccine candidate, mRNA-1010. The decision triggered an immediate negative reaction from investors, with Moderna stock falling as much as 7% to around $39 in late trading.

According to Moderna, the FDA’s Center for Biologics Evaluation and Research (CBER) informed the company that it would not initiate a review of the biologics license application for mRNA-1010. The regulator cited concerns over the absence of an “adequate and well-controlled” clinical study to support the application. Specifically, the FDA criticized Moderna’s choice of comparator in its trials, stating that the vaccine was tested against a standard flu shot that did not represent the “best-available standard of care.”

Moderna emphasized that the FDA did not raise any specific safety or efficacy concerns regarding the mRNA-1010 vaccine. Instead, the disagreement centers on trial design and regulatory expectations. The company argued that the FDA’s stance contradicts prior agency guidance, which, according to Moderna, does not mandate the use of the most advanced available treatment as a comparator in vaccine trials.

The biotech firm also noted that it has requested a meeting with the FDA to discuss the decision and explore potential next steps. Moderna referenced recent commentary from CBER head Vinay Prasad, who has publicly supported U.S. Health Secretary Robert F. Kennedy Jr.’s push for stricter vaccine regulations. This context has raised concerns among investors about a potentially tougher regulatory environment for vaccine developers.

The mRNA-1010 vaccine successfully met all primary endpoints in a Phase 3 clinical trial, Moderna announced in mid-2025. The company has positioned the product as a next-generation combination vaccine targeting both influenza and COVID-19, a strategy seen as central to Moderna’s long-term growth beyond its COVID-era revenues.

The FDA setback adds to ongoing pressure on Moderna shares, which have struggled amid declining demand for COVID-19 vaccines and heightened scrutiny of its pipeline. As investors assess the implications of the FDA’s decision, attention remains focused on whether Moderna can resolve regulatory concerns and advance mRNA-1010 toward eventual approval.