Moderna flu/COVID combo beats immune responses for approved shots in phase 3 after speedy season

Moderna’s combo flu and COVID-19 vaccine zipped through a late-stage trial this winter, and the results are showing a higher immune response than licensed comparators—including the famed biotech’s own Spikevax.

MRNA-1083 is made up of Moderna’s flu shot mRNA-1010 and the next-generation COVID-19 vaccine mRNA-1283. Both components have individually shown efficacy in late-stage trials.

But together, Moderna hopes to create a product that can reduce the burden on patients and caregivers each season.

“One of the things that we learned from the COVID experience is that there is a certain, let's say, fatigue to COVID-19 vaccine, and the difference between the vaccine coverage rates of influenza and COVID is quite substantial,” Francesca Ceddia, M.D., Moderna’s chief medical affairs officer, said in an interview.

Moderna is hoping to offer a one-and-done shot that provides protection for both flu and COVID.

“That is really a big advantage for not only pharmacists, but for health systems. And, of course, there is also a reduced burden in terms of cost for the hospitals, because if you're able to uplift vaccination rates because of the improved compliance, you are likely to prevent more hospitalization and other severe consequences due to COVID and influenza,” Ceddia said.

These combo shots have become a central pillar of Moderna’s next act, as has the recently approved respiratory syncytial virus shot, which will be marketed as mRESVIA.

In the ongoing phase 3 trial, mRNA-1083 was tested in two groups of 4,000 adults each. One group featured adults 65 years or older and compared Moderna’s offering with co-administered Fluzone HD (Sanofi) and Spikevax. The second group had adults aged 50 to 64 years and compared mRNA-1083 to co-administered Fluarix (GSK) and Spikevax.

Across both groups, Moderna’s combo demonstrated noninferiority to the comparators and elicited statistically significantly higher immune responses against three influenza virus strains—H1N1, H3N2 and B/Victoria—and against SARS-CoV-2, Moderna said.

Ceddia said the COVID-19 portion of the combo showed higher responses because it’s an updated vaccine compared to Spikevax.

“The fascinating thing is that we have developed a shorter version of the sequence of the mRNA which is currently available in the licensed vaccine,” she said. “The idea was to have a more stable version that could provide also better storage conditions.”

That would mean mRNA-1083 could be made available at more locations without the complicated storage requirements that proved tricky in the early days of the pandemic. The combo can be stored in a refrigerator, Ceddia explained. The COVID-19 portion of the vaccine also has a lower dose than the approved shot.

Moderna also measured immunogenicity against the B/Yamagata flu strain, meeting noninferiority there as well. However, the World Health Organization has recommended that this strain not be included in vaccines for the 2024/25 flu season as it has disappeared from circulation.

Safety and tolerability for mRNA-1083 was acceptable, according to Moderna, with the majority of adverse reactions listed as grade 1 and 2 and consistent with the licensed products.

The combo vaccine advanced into phase 3 in fall 2023 after phase 1/2 data similarly showed that mRNA-1083 matched or beat two already approved shots for flu and the company’s own Spikevax COVID shot in terms of developing antibody titers. Vaccine trials based on seasonal flu are quick to enroll, Ceddia said. 

MRNA-1083 could soon become Moderna’s third marketed product, although Ceddia was mum on exactly what the next steps are beyond bringing the data to the FDA.

The approval of mRESVIA means Moderna is hard at work rolling out a shot. Ceddia sees that, plus Spikevax and eventually mRNA-1083, as a highly complementary portfolio for the marketing team to advance. It also marks Moderna’s move beyond being a one-trick COVID-19 company.

“The beauty about the fact that they are all respiratory vaccines is that there is potential for a synergistic approach,” she said. “You're targeting the same stakeholders, you are targeting the same population. I see more potential for synergies than complexity.”