When Sanofi and partner GSK announced late last year that their COVID-19 vaccine failed to produce a strong immune response in the over-50s – the age group most vulnerable to the disease – many thought the companies might throw in the towel.
Instead, the companies have pushed on with their candidate, a recombinant adjuvanted vaccine, this week announcing preliminary data on its efficacy as a booster shot.
Data from what the companies is touting as ‘the most comprehensive booster trial to date’ shows that the Sanofi-GSK vaccine delivered consistently strong immune responses regardless of which vaccine was given as a primary course.
The VAT0002 extension trial showed neutralising antibodies increased between 9 and 43-fold following a booster shot regardless of whether the participants received the AstraZeneca, Johnson & Johnson, Moderna or Pfizer-BioNTech vaccine. Crucially for the partnership, the data applies across all age groups tested.
In May, the companies announced that its vaccine candidate demonstrated strong immune responses across all adult age groups in its phase 2 VAT0002 trial.
The companies’ phase 3 trial, VAT008, is ongoing but its independent data safety monitoring board has recommended it continue into 2022 in order to collect more data. The board wants the trial to include more COVID-19 naïve participants, which has been difficult due to the rising number of infections.
“These preliminary data show we have a strong booster candidate, whatever primary vaccine you have received.” said Sanofi Pasteur’s Thomas Triomphe. “While pursuing a phase 3 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.”
Roger Connor, president of GSK Vaccines, added: “As the pandemic threat continues with the current dominant Delta variant and Omicron rapidly gaining ground, booster vaccines will continue to be needed to help protect people over time. The initial booster data are promising, and we await the phase III results to determine the next steps on making protein-based adjuvanted COVID-19 vaccines available.”
The VAT0002 booster trial saw 521 participants who had been vaccinated according to the approved dosing schedule receive a single dose the Sanofi-GSK vaccine candidate four and ten months after the primary vaccination.
The phase 3 efficacy trial, VAT0008, is a randomised, double-blind, placebo-controlled trial for the prevention of symptomatic COVID-19 in adults with secondary endpoints of preventing severe COVID-19 disease and infection. The 10,000 participants will receive two doses of the Sanofi-GSK vaccine with efficacy assessed firstly against the original SARS-CoV-2 virus and secondly against the Beta variant.