Vaxxinity will push for approval of COVID booster after trial shows noninferiority to market leader Pfizer

Vaxxinity’s next-gen COVID-19 booster candidate has hit its safety targets in a head-to-head trial against Pfizer-BioNTech’s, AstraZeneca’s and Sinopharm’s vaccines. The biotech now plans to push ahead for approval in several countries, despite performing similarly but ultimately failing to beat Pfizer's shot when it came to efficacy.

The Dallas-based biotech’s phase 3 study is evaluating UB-612, a single heterologous COVID-19 booster candidate in comparison to three major globally authorized competitors: Pfizer and BioNtech's mRNA-based Comirnaty; AstraZeneca’s adenovirus-vectored shot; and Sinopharm's inactivated virus.

The study enrolled 944 participants who had received initial shots of one of these authorized vaccines and were then given Vaxxinity's shot as a booster. The trial’s main goals are safety, tolerability, and live virus-neutralizing antibody titers against the original strain of COVID-19 at day 29.

The trial hit its primary safety goals, with no serious adverse events reported, according to topline results posted Dec. 2. The study is ongoing, and the long-term safety profile continues to be assessed.

UB-612 also elicited superior neutralizing antibody titers and seroconversion rates against both the original strain and omicron BA.5 variants when compared to AstraZeneca’s and Sinopharm’s vaccines, but failed to show statistically significant superiority against Pfizer-BioNTech’s shot. Vaxxinity's booster demonstrated "non-inferiority" compared to Pfizer's, performing slightly better but not enough to hit clinical significance.

“Given these phase 3 topline results, and UB-612’s generally lower cost structure and ease of distribution, we believe UB-612 has the potential to serve as an optimal choice for boosting, especially in developing countries, as COVID-19 enters an endemic stage,” Vaxxinity CEO Mei Mei Hu, said in a company release. “After multiple clinical trials, we have consistently shown that UB-612 is well tolerated, continues to elicit broad coverage against emerging variants, and generates a durable neutralizing antibody titer.”

The company touted UB-612 as "the first multitope subunit protein/peptide-based vaccine candidate" for COVID-19. The shot is designed to activate both B- and T-cell arms of the immune system.

“This is a championship moment for Vaxxinity's COVID booster, performing just as well as Pfizer/BioNTech, the most commercially successful vaccine in history," Hu told Fierce Biotech via email. 

Vaxxinity plans to complete rolling submissions with regulatory agencies in the U.K. and Australia for potential marketing authorizations of UB-612 in the first half of 2023. The Coalition for Epidemic Preparedness Innovations has helped fund the study, which will formally wrap in the second half of next year.  

Since closing at $2.38 per share yesterday, Vaxxinity’s stock sunk 15% to $2 as of 1:30 p.m. ET today.

Editor's note: This article was updated 1:30 p.m. ET Dec. 2 to include comments from Hu and further data clarification.