Novavax's experimental COVID-19-influenza combination and standalone influenza vaccines generated a strong immune response in adults aged 65 and older, similar to already approved shots against the viruses in a late-stage trial.

Both the vaccine candidates were well tolerated with no new safety concerns, the biotech said on Wednesday.

Its shares rose 1.3% to $7.29 in premarket trading.

The study, which involved about 2,000 participants, tested the safety and immune response of the COVID-influenza combination and standalone flu vaccines compared to its COVID-19 shot Nuvaxovid and Sanofi's flu shot Fluzone HD, respectively.

Novavax said the study was not designed to show statistically significant results. The data will be used to design a future late-stage study, which can be submitted for regulatory approval, it said.

The Maryland-based biotech, which is shifting its focus to commercializing its candidates through partnerships, said it continues to look for partners that can advance further development of these experimental vaccines.

It had signed a licensing deal with Sanofi worth up to $1.2 billion last year to commercialize and further develop its COVID-19 vaccine, Nuvaxovid.

Nuvaxovid gained the U.S. approval last month after the Food and Drug Administration missed an April 1 target to approve the shot.

The approval, however, limited its use to older adults and at-risk individuals over the age of 12. The traditional protein-based shot offers an alternative to its messenger RNA-based rivals from Pfizer/BioNTech and Moderna.

Earlier this week, Health Secretary Robert F. Kennedy Jr., a long-time vaccine skeptic, fired all members of a U.S. Centers for Disease Control and Prevention panel of vaccine experts — a move public health experts said could undermine confidence in currently available shots.