Sanofi and GSK will submit data from both their booster and Phase 3 efficacy trials to the FDA and other international regulatory agencies for authorization of their Sanofi-GSK COVID-19 vaccine. According to data from the companies, a two-dose regimen of the vaccine had a 57.9% efficacy against any symptomatic COVID-19 disease in the seronegative population and provided 100% protection against severe disease and hospitalizations and 75% efficacy against moderate-to-severe disease in seronegative populations.
In participants who had received a primary series of an already authorized mRNA or adenovirus vaccine, the Sanofi-GSK booster vaccine induced a significant increase in neutralizing antibodies of 18- to 30-fold across vaccine platforms and age groups. When the Sanofi-GSK vaccine was used as a two-dose primary series followed by a booster dose, neutralizing antibodies increased 84- to 153-fold compared to pre-boost levels, according to the companies.
Additional findings from the studies included:
- When used as a two-dose primary series, the Sanofi-GSK vaccine delivered robust levels of neutralizing antibodies, with GMTs reaching 3711 units.
- Two doses of Sanofi-GSK vaccine generated an efficacy of 57.9% (95% confidence interval [CI, 26.5, 76.7]) against any symptomatic COVID-19 disease in the seronegative population.
- The Sanofi-GSK vaccine provided 100% protection (0 vs 10 cases post-dose 1, 0 vs 4 cases post-dose 2) against severe disease and hospitalizations and 75% (3 vs 11 cases) efficacy against moderate-to-severe disease in seronegative populations.
- While sequencing is still in progress, early data indicate 77% efficacy against any Delta variant-associated symptomatic COVID-19 disease, in line with expected vaccine effectiveness.
Across both studies, the Sanofi-GSK vaccine was well-tolerated in younger and older adults with no safety concerns.
The companies are in discussions with regulatory authorities, including the US FDA and European Medicines Agency (EMA), and plan to submit the totality of the data generated with this vaccine candidate to support regulatory authorizations.
“We’re very pleased with these data, which confirm our strong science and the benefits of our COVID-19 vaccine,” said Thomas Triomphe, Executive Vice President, Sanofi Vaccines. “The Sanofi-GSK vaccine demonstrates a universal ability to boost all platforms and across all ages. We also observed robust efficacy of the vaccine as a primary series in today’s challenging epidemiological environment. No other global Phase 3 efficacy study has been undertaken during this period with so many variants of concern, including Omicron, and these efficacy data are similar to the recent clinical data from authorized vaccines.”
Roger Connor, President of GSK Vaccines, added: “The evolving epidemiology of COVID-19 demonstrates the need for a variety of vaccines. Our adjuvanted protein-based vaccine candidate uses a well-established approach that has been applied widely to prevent infection with other viruses including pandemic flu. We are confident that this vaccine can play an important role as we continue to address this pandemic and prepare for the post-pandemic period.”