Sanofi and GSK have announced that data from their booster and Phase 3 efficacy trials would be used to support regulatory applications for a COVID-19 vaccine.
The production of significant immune responses and a favourable safety profile in diverse contexts underscore the public health significance of Sanofi-refrigerator GSK’s temperature-stable adjuvanted protein-based vaccine. The Sanofi-GSK booster vaccination caused a significant rise in neutralising antibodies of 18 to 30-fold across vaccine platforms and age categories in participants who had already received a primary series of an already authorised mRNA or adenovirus vaccine.
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 (see Figures 1a and 1b for details).
Thomas Triomphe, Executive Vice President, Sanofi Vaccines, said: “We’re very pleased with these data, which confirm our strong science and the benefits of our COVID-19 vaccine. 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, said: “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.”
When used as a two-dose primary series, the Sanofi-GSK vaccine delivered robust levels of neutralizing antibodies, with GMTs reaching 3711 units. For comparison, a panel of sera from volunteers in the same age range who received two doses of an already approved and highly effective mRNA vaccine displayed a GMT of 1653 units, measured simultaneously in the same laboratory.
Data from the VAT08 efficacy study showed that 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.