The companies have also started development work on how to respond to new SARS-CoV-2 variants.
In 2020, Sanofi and GSK partnered to develop an adjuvanted recombinant protein COVID-19 vaccine candidate. However, in December, they announced a delay to the program as Phase 1/2 interim results showed an insufficient immune response in older adults, requiring the need to refine the concentration of antigen in order to provide high-level immune responses across all age groups.
The new Phase 2 study will assess the refined antigen formulation and be used to select the most appropriate antigen dosage. The randomised, double-blind, multi-center study will cover adults 18+, with an equal number of adults in the 18-59 category and the 60+ category. A total of 720 volunteers will be recruited in the US, Honduras and Panama. Two doses of the vaccine will be administered 21 days apart.
The Phase 2 study will inform the Phase 3 protocol, with this trial scheduled for Q2. This could be followed by applications for regulatory authorization in the second half of 2021, with the vaccine becoming available in Q4 2021 (the initial target, before revamping the vaccine, had been for the first half of 2021).
“Over the past few weeks, our teams have worked to refine the antigen formulation of our recombinant-protein vaccine, based on learnings from our initial Phase 1/2 study.” said Thomas Triomphe, Executive Vice President and Head of Sanofi Pasteur.
“We are confident that our vaccine candidate has strong potential and we are very encouraged by the latest preclinical data. This new Phase 2 study will enable us to identify the final vaccine formulation for adults of all ages.”