The FDA’s CBER issued a refusal-to-file letter for Moderna’s flu vaccine mRNA-1010.
- The regulator said the Phase 3 study comparator did not reflect the “best-available standard of care,” though it raised no safety or efficacy concerns.
- Moderna said the refusal conflicts with prior FDA guidance that allowed the comparator.
- CEO Stephane Bancel will seek clarity through a requested Type A meeting.
Shares of Moderna, Inc. (MRNA) fell about 9% in after-hours trading on Tuesday after the company said U.S. regulators declined to accept its application for review of its experimental seasonal influenza vaccine, marking another regulatory setback for the vaccine maker.
In the regular session, MRNA stock rose 0.1% to $41.99. The regulatory setback also lifted shares of rival Novavax, which is developing a protein-based seasonal influenza vaccine candidate, with the stock rising more than 1% in after-hours trading.
FDA Rejects Moderna Flu Vaccine Filing
Moderna said the U.S. Food and Drug Administration’s (FDA) Center for Biologics Evaluation and Research (CBER) issued a refusal-to-file letter for the biologics license application (BLA) of its investigational flu vaccine, mRNA-1010, and will not initiate a review, despite the company using a priority review voucher.
The letter said the application lacked an “adequate and well-controlled” study using a comparator reflecting the “best-available standard of care,” and did not raise any safety or efficacy concerns.
The BLA includes two positive Phase 3 studies enrolling 43,808 participants. One showed a stronger immune response and a favorable safety profile compared with a high-dose flu shot in adults aged 65 and older, while the other showed higher effectiveness than a standard-dose vaccine in adults aged 50 and older. Moderna said the FDA reviewed and cleared both trial designs before the studies began.
The decision was signed by Vinay Prasad, who is also known for halting broader access to Sarepta Therapeutics’ gene therapy Elevidys, drawing backlash over access to the only approved treatment for Duchenne muscular dystrophy.
Moderna Flags Inconsistency In FDA Feedback
Moderna said the refusal conflicted with earlier written guidance from the FDA’s CBER. In April 2024, regulators said using a licensed standard-dose influenza vaccine as the comparator would be acceptable, while recommending a high-dose or an adjuvanted vaccine for participants aged 65 and older. The company said no objections or clinical holds were raised after the Phase 3 protocol was submitted or before the trial began in September 2024.
After the Phase 3 study met all pre-specified endpoints, Moderna said it provided additional comparator analyses requested during an August 2025 pre-submission meeting, including data from a separate Phase 3 trial comparing a licensed high-dose flu vaccine with a comparator. Moderna said the FDA did not signal it would refuse to review the application.
CEO Stephane Bancel said the decision was based on no safety or efficacy issues and that the company would seek clarity on the path forward.
Moderna Seeks Type A FDA Meeting
Moderna said it has requested a Type A meeting with CBER. The company said mRNA-1010 has been accepted for review in the European Union, Canada and Australia, with additional country submissions planned for 2026. It expects the earliest potential approvals outside the U.S. in late 2026 or early 2027 and said the FDA decision will not affect its 2026 financial guidance.
Regulatory Backdrop Weighs On Vaccine Makers
The FDA decision adds to regulatory uncertainty facing vaccine manufacturers in the U.S. Last month, Bancel told Bloomberg at the World Economic Forum in Davos that Moderna does not plan to invest in new late-stage vaccine trials without clearer access to the U.S. market, citing regulatory delays and reduced support for immunization programs.
In December, a leaked internal email from Prasad surfaced, asserting that COVID-19 vaccines were linked to at least 10 pediatric deaths, a claim experts said lacked supporting data. Moderna has been seeking to diversify beyond its COVID-19 vaccines and is focusing on personalized cancer vaccines, while also looking for external funding partners to advance certain late-stage vaccine programs.
How Did Stocktwits Users React?
On Stocktwits, retail sentiment for MRNA was ‘bearish’ amid ‘low’ message volume.
One bearish user said, “So glad I sold at $49 this time round. This is going to struggle to stay solvent soon.”
Another user called the company a “Great short!” and expects the stock to trade in the range of $20-$28.
MRNA stock has risen 32% over the past 12 months.
See Also: MRNA Vs NVAX: Which Vaccine Stock Is Wall Street More Bullish On Right Now?
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