TLDR
- Moderna (MRNA) stock fell 9% premarket Wednesday after FDA issued refusal-to-file letter for flu vaccine
- FDA rejected mRNA-1010 application over trial design methodology, not vaccine safety or effectiveness
- Regulatory agency wanted “best available care” comparator, not standard flu shot used in study
- Company’s 40,000-person trial demonstrated 26.6% greater effectiveness versus approved flu vaccine
- Moderna claims FDA decision conflicts with previous regulatory guidance and requests clarification meeting
Moderna (MRNA) stock took a hit Wednesday following an unexpected regulatory setback. The biotech company saw shares drop 9% in U.S. premarket trading after the FDA rejected its flu vaccine application.
European markets showed the impact first, with Frankfurt trading opening 14% lower. Volume remained thin during early morning sessions.
The FDA sent Moderna a refusal-to-file letter for mRNA-1010, its seasonal influenza vaccine. This type of rejection means the agency won’t even begin reviewing the application.
The problem centers on how Moderna designed its clinical trial. FDA vaccine director Dr. Vinay Prasad said the study design didn’t meet regulatory standards.
The agency specifically objected to Moderna’s choice of comparator vaccine. Prasad stated that comparing mRNA-1010 to a standard flu shot doesn’t reflect “best available care” practices.
Clinical Data Under Scrutiny
Moderna ran its trial with more than 40,000 participants across multiple sites. The company used Fluarix, an approved flu vaccine, as its comparison product.
September 2025 data showed promising results. The mRNA-1010 vaccine proved 26.6% more effective than the FDA-approved comparator shot.
The FDA made clear it found no issues with the vaccine’s safety profile. The agency also didn’t raise concerns about how well the vaccine works.
The entire rejection hinges on trial methodology alone. This distinction matters for Moderna’s next steps forward.
Company Pushes Back on Decision
CEO Stéphane Bancel expressed frustration with the FDA’s position. He argues that regulations don’t require using the most advanced vaccine as a comparator.
Moderna points to earlier communications with the FDA. The company says guidance from 2024 and 2025 contradicted this week’s rejection.
Bancel stated the decision doesn’t support American leadership in medical innovation. He questioned why using an FDA-approved comparator should create controversy.
The company has formally requested a meeting with FDA officials. Moderna wants clarity on what changes might satisfy regulatory requirements.
Options include redesigning the trial with a different comparator. The company could also explore alternative approval pathways.
Regulatory Climate Shifts
The rejection comes during a period of vaccine policy changes. HHS Secretary Robert F. Kennedy Jr. has overseen new approaches to immunization recommendations.
FDA officials recently scaled back COVID-19 vaccine guidance. The agency added new warning labels to mRNA vaccine products.
Advisory panel membership has changed too. The FDA removed critics of current administration policies from key committees.
HHS plans to cancel more than $500 million in mRNA vaccine-related contracts. This represents a major shift in federal vaccine funding priorities.
Historically, flu vaccines received streamlined annual updates. A 2025 memo from Prasad proposed ending this faster approval process.
Former FDA commissioners criticized the proposal publicly. Over a dozen ex-officials published an editorial opposing the change.
Moderna’s stock performance shows resilience despite the setback. Shares remain up 42% for the year before Wednesday’s decline.
The company closed Tuesday up 0.1% before news broke. Frankfurt’s low-volume trading provided the first market reaction.
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