Sanofi reports data from two trials, VAT02 Cohort 2 and COVIBOOST VAT013, conducted with its new next-generation COVID-19 booster vaccine candidate modelled on the Beta variant antigen and including GSK’s pandemic adjuvant.

In the Phase 3 VAT02 Cohort 2 study, the Sanofi-GSK next-generation vaccine candidate induced (at day 15 post-immunization) a significant boost in antibody titers above baseline against multiple variants of concern (15-fold increase against D614 parent virus, 30-fold increase against Beta strain) in adults previously primed with mRNA COVID-19 vaccines. In particular against Omicron, preliminary data show a 40-fold increase against BA.1. The Sanofi-GSK next-generation booster candidate generated double the number of neutralizing antibodies against Omicron BA.1 and BA.2 compared to the D614-based (original parent virus) booster.

In parallel, the independent COVIBOOST (VAT013) study conducted by the Assistance Publique – Hôpitaux de Paris (AP-HP) demonstrated that, following primary vaccination with two doses of Pfizer-BioNTech’s Comirnaty vaccine, the Sanofi-GSK next-generation booster candidate generated a higher immune response (as measured by neutralizing antibody titers) than Pfizer-BioNTech’s booster or the Sanofi-GSK first-generation booster, both of which target the original D614 parent strain. The proportion of participants with at least a 10-fold increase in neutralizing antibody titers for the original D614 SARS-CoV-2 strain between day 0 and day 15 was:

76.1% (95% CI 64.5–85.4) for the Sanofi-GSK next-generation booster, vs

63.2% (95% CI 51.3–73.9) for the Pfizer BioNTech D614 booster, and

55.3% (95% CI 43.4–66.7) for the Sanofi-GSK D614 (first-generation parent booster candidate).

In this study, which included 247 subjects, all the three vaccines also elicited neutralizing antibodies against the Omicron BA.1 variant, with highest responses generated by the Sanofi-GSK next-generation candidate. Results of COVIBOOST study are available on a pre-print server, pending publication in a peer-reviewed journal.

Across both studies, the Sanofi-GSK next-generation vaccine candidate was well-tolerated, with a favorable safety profile. In the VAT02 cohort 2 study, low numbers (less than 4%) of Grade 3 reactions were reported, all transient and non-severe.

Thomas Triomphe, Executive Vice President, Sanofi Vaccines, said : “COVID-19 keeps evolving and the combination of emergence of variants and waning immunity is likely to lead to the need for additional booster shots, at least in some populations. The Beta variant expresses similar mutations across multiple variants of concern, including Omicron, making it a strong vaccine candidate to confer broad protection against multiple strains of COVID-19. Seeing the cross-neutralization data from the independent AP-HP study, we believe this next-generation booster could have an important role to play for public health vaccination campaigns. We look forward to submitting these data to global regulatory authorities.”

Sanofi and GSK have developed their next-generation booster candidate in parallel to ongoing regulatory reviews of their first-generation vaccine candidate. The totality of data supporting this next-generation booster vaccine will be submitted to regulatory authorities in the upcoming weeks, with the aim of making it available later this year.