Novavax touts early data for flu-COVID combo vaccine as FDA decision looms for single shot

Novavax says its combo flu and COVID vaccine elicits a strong immune response similar to standalone flu and COVID jabs, according to initial results of a phase 1/2 trial. 

The results, announced Wednesday, came from a phase 1/2 trial in 642 older adults between 50 to 70 conducted in Australia. One hundred percent of the participants had been vaccinated by an initial series of one of the available COVID vaccines. The objective of the trial was to identify an optimal dose of the vaccine using a modelling-based approach. 

Preliminary results found that the combo shot elicited similar immune response to both a standalone influenza vaccine as well as a standalone COVID shot. Additionally, the modeling found that combined formulation could reduce total antigen amount by up to 50%, which could boost production and delivery.

On the horizon for Novavax is launching a phase 3 study, ideally during the upcoming flu season should flu rates be high enough. However, the number of flu cases have plummeted since COVID began to circulate globally. 

The company previously reported in 2021 that the flu vaccine, dubbed NanoFlu, had higher immunogenicity than Sanofi's Fluzone Quadrivalent against both homologous and hereologous strains. The company’s COVID vaccine, NVX-CoV2373, was found to be nearly 90% effective in a phase 3 trial; however, that was before the omicron variant became the most dominant strain worldwide. In December 2021, the company reported that neutralization levels were fourfold lower against omicron than the prototype, suggesting “both a booster dose as well as an omicron-specific vaccine may be beneficial.” That same month, the company said it was working on an omicron-specific vaccine.

In a media briefing Thursday, Filip Dubovsky, M.D., chief medical officer for Novavax, expressed confidence that the vaccine’s recombinant protein-based nanoparticle technology would allow the combo shot to be tweaked accordingly. 

“The beauty and the flexibility of our platform is that it’s not a big deal for us,” he said. “If we’re generating an omicron vaccine we can easily incorporate it into a quadravalent product like we have for flu. If there’s a bivalent, and that needs to be incorporated in, that’s a possibility as well.” 

But little has come easy with regard to the company’s COVID vaccine. Novavax had expected the shot to be authorized by the FDA in May 2021 but now, almost a year later, a decision is still pending. Novavax did not end up applying for emergency use authorization until January of this year. And in a meeting of CDC advisors Wednesday to discuss booster doses, Doran Fink, Deputy Director-Clinical, Division of Vaccines and Related Products Applications at the FDA, reportedly suggested that the agency still needed more data from the company. 

Hours before CDC advisors met, Dubovsky said that the FDA had conveyed it plans to convene the its own outside advisors to discuss the jab but has yet to indicate when that would be. The company is also expecting to apply for full approval in the second half of the year. NanoFlu is similarly not yet authorized in the U.S.

Tuesday, the company won approval of the COVID shot in Japan as both a primary series and a booster. Novavax and Takeda partnered up on commercialization and manufacturing efforts in the country. It’s the first approval the company has nabbed for both primary vaccination and a booster shot. It’s also been authorized elsewhere, including in the EU and by the World Health Organization. 

Editor's note: This story was updated to include more context on Novavax's COVID vaccine timeline and included comments from Doran Fink. The story was also amended to note that a future phase 3 trial of the combo vaccine is not the immediate next step in the development process.