Sanofi-GSK Vaccine Shows 100% efficacy Against Severe COVID-19, Discussions Underway For Regulatory Authorization
Sanofi and GSK on Wednesday announced that they are planning to seek regulatory authorization for their COVID- 19 vaccine and intend to submit data generated from both their booster and Phase 3 efficacy trials as the basis for regulatory applications. The companies are already in discussions with regulatory authorities, including the US FDA and European Medicines Agency (EMA) for the same.
For the development of the refrigerator temperature-stable adjuvanted protein-based vaccine candidate, Sanofi provides its recombinant antigen and GSK contributes its pandemic adjuvant, both established vaccine platforms that have proven successful against influenza.
The efficacy of Sanofi-GSK vaccine
Trials showed that the Sanofi-GSK vaccine produced robust levels of neutralizing antibodies, with GMTs reaching 3711 units, when used as a two-dose primary series. In comparison, sera samples 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.
In the VAT08 efficacy study, two doses of the Sanofi-GSK vaccine in seronegative populations demonstrated 100 per cent efficacy against severe COVID-19 disease and hospitalizations, 75 per cent efficacy against moderate or severe COVID-19 disease and 57.9 per cent efficacy against any symptomatic COVID-19 disease.
While sequencing is still in progress, early data indicate 77 per cent efficacy against any Delta variant-associated symptomatic COVID-19 disease, in line with expected vaccine effectiveness, the vaccine makers said in a press release.
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, the release said.
Across both studies, the vaccine was well-tolerated in younger and older adults with no safety concerns, it added.
What the makers have to say
Thomas Triomphe, Executive Vice President, Sanofi Vaccines, said, “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, 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.”
More about VAT08 and VAT02 trails
The Phase 3 trial, VAT08, is evaluating a 10 g antigen formulation of the SARS-CoV-2 adjuvanted recombinant protein-based vaccine for efficacy, immunogenicity and safety compared to a placebo. Stage one of the trial is assessing the efficacy of a vaccine formulation containing the spike protein against the original D614 (parent) virus in more than 10,000 participants >18 years of age, randomized to receive two doses of 10 g vaccine or placebo at day 1 and day 22 across sites in the US, Asia, Africa and Latin America. Enrolment recently completed for a second stage in the trial, evaluating a second bivalent formulation, including the spike protein of the B.1.351 (Beta) variant.
The Phase 3 trial follows positive initial results from a Phase 2 clinical trial (VAT00002). In that trial, the COVID-19 vaccine candidate was administered to 722 adults to assess the safety, reactogenicity and immunogenicity of 2 doses and to identify an optimal dosing for use as a booster. Results showed strong rates of neutralizing antibody response with 95-100 per cent seroconversion following a second injection in all age groups (18 to 95 years old), across all doses.
Full study results for both VAT08 and VAT02 will be published later this year, the companies stated.
