GSK, Sanofi to seek regulatory authorization for COVID vaccine

The public health relevance of the refrigerator temperature-stable adjuvanted protein-based Sanofi-GSK vaccine is strongly supported by the induction of robust immune responses and a favorable safety profile in multiple settings. 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.

"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," said Thomas Triomphe , Executive Vice President, Sanofi Vaccines.

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.

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