Moderna on Monday said its experimental mRNA-based flu vaccine produced a stronger immune response than a currently available shot in a late-stage trial, clearing a path forward for the product and the company's separate combination flu and Covid jab.

Moderna in May voluntarily withdrew an application seeking approval of its combination shot targeting Covid-19 and influenza, saying it had plans to resubmit it with efficacy data from the phase three trial on its stand-alone flu vaccine. That decision came after discussions with the Food and Drug Administration, which is grappling with a massive overhaul under Health and Human Services Secretary Robert F. Kennedy Jr., a prominent vaccine skeptic.

With the new data, the company plans to resubmit the application for the combination vaccine and file for approval of its stand-alone flu shot later this year, Stephen Hoge, the company's head of research and development, said in an interview.

If regulators approve the flu vaccine, the company can then advance the combination shot, Hoge said. He added that Moderna expects approvals for both shots next year pending reviews.

Moderna shares climbed nearly 3% in premarket trading Monday.

Hoge said the combination jab simplifies vaccination, which will "help the health-care system" by reducing the workloads of doctors and nurses, slashing costs, and improving uptake among patients.

The company so far appears to be the front-runner in the race against Pfizer and Novavax to bring a combination shot to the market. While Moderna does not have specific revenue projections for its individual products, Hoge said Covid, flu and respiratory syncytial virus are each multibillion-dollar markets.

"We're obviously hoping that our products allow us to earn our fair share of them," he said.

The phase three trial followed more than 40,000 adults ages 50 and above, who were randomly assigned to receive a single dose of Moderna's shot, called mRNA-1010, or a standard competitor vaccine. Moderna's shot was 26.6% more effective than the other vaccine in the overall study population. 

The mRNA-1010 jab also demonstrated strong efficacy for each of the major influenza strains in the shot, including A/H1N1, A/H3N2 and the B/Victoria lineages. Moderna said the vaccine's benefit was consistent across different age groups, people with various risk factors and previous vaccination status against the flu. 

In adults ages 65 and older, the shot was 27.4% more effective than the standard flu vaccine. 

The efficacy results are "a significant milestone in our effort to reduce the burden of influenza in older adults," Moderna CEO Stephane Bancel said in a release. "The severity of this past flu season underscores the need for more effective vaccines."

Moderna cited data from the Centers for Disease Control and Prevention showing that seasonal flu-related hospitalizations and outpatient visits reached a 15-year high during the 2024 to 2025 season of the virus. More than 600,000 Americans were hospitalized due to flu-related illness last year, according to the CDC. 

The mRNA-1010 vaccine's safety data was consistent with previous results from another phase three study on the shot. 

Shares of Moderna were down more than 30% for the year entering Monday, fueled in large part by a string of moves by the Trump administration to change vaccine policy and undermine immunizations. The administration in May canceled a contract awarded to Moderna for the late-stage development of its bird flu vaccine for humans. 

When asked about the uncertain regulatory environment in the U.S., Hoge said Moderna is engaging closely with the FDA to understand what its requirements are and how to satisfy them.

"I believe, as relates to flu, I think we've got a pretty clear path," he said.