Sanofi and GlaxoSmithKline (GSK) have reported that the booster shot of their recombinant adjuvanted vaccine candidate for Covid-19 offered robust immune responses in the Phase III VAT0002 clinical trial.
The heterologous booster trial analysed the safety and immunogenicity of Sanofi-GSK’s protein-based vaccine when administered following inoculation with any of the four approved Covid-19 shots as part of the initial vaccine regimen.
The approved vaccines included those developed by Moderna, Pfizer-BioNTech, AstraZeneca and Johnson & Johnson.
According to the initial data, the booster demonstrated a nine-fold to 43-fold increase in neutralising antibodies in people who were inoculated with the approved vaccines and in all people of age groups tested in the trial.
The booster was also found to be well-tolerated, with a safety profile in line with the currently approved vaccines.
The independent Data Safety Monitoring Board (DSMB) of the international Phase III VAT0008 trial underway, recommended progressing the trial into early next year for obtaining additional data.
The DSMB advice comes after no safety concerns linked to the vaccine were detected in its review.
Regulatory agencies need Phase III efficacy to be established in ‘naive’ individuals, i.e. people who are not Covid-19 infected.
In the third quarter of this year, Phase III enrolled most subjects when a rise in cases due to the Delta variant was reported worldwide.
The study will progress to accrue the number of events required for assessment in order to provide the essential data to regulatory agencies for the booster shot submission.
The trial results are anticipated to be reported in the first quarter of next year.
Sanofi Pasteur executive vice-president Thomas Triomphe said: “These preliminary data show we have a strong booster candidate, whatever primary vaccine you have received.
“This is consistent with our efforts to provide relevant responses to evolving public health needs. While pursuing a phase III trial is a challenge in a quickly shifting pandemic environment, we look forward to seeing the results to support submissions of our booster vaccine as quickly as possible.”
In May, the companies started subject enrolment in a Phase III trial of their adjuvanted recombinant-protein Covid-19 vaccine candidate.