MRNA Down Nearly 10% as FDA Refuses to Review Influenza Vaccine BLA

Moderna MRNA shares plunged around 10% in after-hours trading following the announcement that the FDA’s Center for Biologics Evaluation and Research (CBER) has issued a Refusal-to-File (RTF) letter for the biologics license application (BLA) seeking approval of its investigational influenza vaccine, mRNA-1010. The company submitted the BLA for mRNA-1010 in January in the United States.

FDA Felt the Comparator Was Not the “Best Available” Option

The FDA refused to begin review of the BLA for the seasonal flu vaccine, stating that the licensed standard-dose seasonal influenza vaccine, which Moderna used as the comparator in the phase III study, was not the best available standard of care. As a result, the agency concluded that the late-stage study was not adequate and well-controlled. However, CBER did not raise any safety or efficacy concerns regarding mRNA-1010.

Over the past year, MRNA’s shares have surged 37.5% compared with the industry’s 18.7% rise.

Prior Regulatory Guidance From CBER

Moderna stated that the RTF letter was inconsistent with CBER’s prior written communications. During a pre-phase III consultation in April 2024, CBER indicated that a licensed standard-dose influenza vaccine would be an acceptable comparator, while recommending a higher-dose influenza vaccine, such as Sanofi’s Fluzone High-Dose, Flublok or Seqirus’ Fluad as a comparator for participants aged 65 years and older.

However, CBER agreed to include appropriate disclosures in the informed consent form if a standard-dose influenza vaccine was used as the comparator in participants aged 65 years and older. It raised no objections or clinical hold prior to the study initiation.

Following the successful completion of the late-stage study on mRNA-1010, which met the primary endpoints, Moderna provided supportive analyses requested by CBER, including data from a separate phase III P303 Part C study evaluating mRNA-1010 against a licensed high-dose influenza vaccine in August 2025.

MRNA has requested a Type A meeting with the FDA to address the issues outlined in the RTF letter and to establish the path forward.

More on mRNA-1010

mRNA-1010 is currently under regulatory review in the European Union, Canada and Australia, and the company plans to file for approval in additional countries in 2026.

Earlier, Moderna said it expected approval of mRNA-1010 in the United States in late 2026. However, the latest RTF will probably delay the approval.

MRNA’s Zacks Rank & Stocks to Consider

Moderna currently carries a Zacks Rank #3 (Hold).

Some better-ranked stocks in the biotech sector are Exelixis EXEL, Alkermes ALKS and Castle Biosciences CSTL, each currently sporting a Zacks Rank #1 (Strong Buy). You can see the complete list of today’s Zacks #1 Rank stocks here.

Over the past 60 days, estimates for Exelixis’2026 earnings per share have risen from $3.18 to $3.39. EXEL shares have surged 31% over the past year.

Exelixis’ earnings beat estimates in each of the trailing four quarters, with the average surprise being 21.39%.

Over the past 60 days, estimates for Alkermes’ 2026 earnings per share have increased from $1.54 to $1.91. ALKS shares have risen 3.6% over the past year.

Alkermes’ earnings beat estimates in three of the trailing four quarters and missed in the remaining one, with the average earnings surprise being 4.58%.

Over the past 60 days, estimates for Castle Biosciences’ 2026 loss per share have narrowed from $1.06 to 96 cents. CSTL shares have risen 16.2% over the past year.

Castle Biosciences’ earnings beat estimates in three of the trailing four quarters and missed in the remaining one, with the average surprise being 66.11%.

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This article originally published on Zacks Investment Research (zacks.com).

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