Beta vaccine, alpha player? Sanofi, GSK post next-gen COVID-19 jab data to unlock booster market

Sanofi and GSK have shared a glimpse of the data they plan to use to bring a next-generation COVID-19 booster vaccine to market this year. The data drop covers two clinical trials that suggest the beta-specific vaccine can induce a stronger response against the omicron variant than first-generation products can.

After ceding a head start to BioNTech-Pfizer and Moderna, Sanofi and GSK suffered a setback late in 2020 when a phase 1/2 trial of their adjuvanted recombinant protein-based vaccine delivered weak data. The partners responded by advancing a revised formulation, leading them to report 58% protection against symptomatic COVID-19 in a variant-affected phase 3 clinical trial early this year.

The opportunity for Sanofi and GSK’s first vaccine appears limited, given the extent to which the mRNA players have sewn up the primary series and booster markets, but the falling rates of protection against omicron could allow the entry of next-generation candidates. Sanofi and GSK are pursuing that potential opportunity by advancing a vaccine candidate against beta, a variant of concern that features some of the mutations that enable omicron to escape the immune system.

To evaluate the beta candidate, Sanofi and GSK enrolled 1,500 subjects in a second cohort of their phase 3 booster study. The candidate triggered a 40-fold increase in antibody titers against the BA.1 subvariant of omicron in patients previously primed with mRNA vaccines. The two companies linked the jab to double the number of neutralizing antibodies against the BA.1 and BA.2 subvariants as their original vaccine. 

The partners are yet to share detailed data from the trial—a peer-reviewed publication is planned—but are confident enough in the findings to plan to submit the results to regulators in “the upcoming weeks” and aim to bring the beta candidate to market later this year.

A separate, independent trial run by at 11 sites in France has provided a closer look at the effects of the beta candidate. In a preprint paper, the researchers reported the findings of a trial that randomized 247 subjects to receive the first-generation Sanofi-GSK vaccine, its beta-specific successor or BioNTech and Pfizer’s Comirnaty as a booster. Neutralizing antibodies against BA.1 went from 17.4 to 253.2 in recipients of the beta vaccine, compared to an increase of 19.1 to 139.5 in the Comirnaty cohort. 

While the data suggest Sanofi and GSK’s beta-specific vaccine may offer more protection than authorized vaccines against currently circulating forms of SARS-CoV-2, in the real world the companies could be up against next-generation mRNA shots. Both Pfizer-BioNTech and Moderna have omicron-specific COVID-19 jabs in development that could be available in the fall.