Sanofi and GlaxoSmithKline (GSK) have begun a new Phase II study with 720 volunteers aged 18 and over to select the most appropriate antigen dosage for Phase III evaluation of their adjuvanted recombinant protein COVID-19 vaccine candidate.
“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 I/II 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 II study will enable us to identify the final vaccine formulation for adults of all ages. We have demonstrated our commitment to focusing efforts and capabilities towards the global fight against the pandemic, and this new study takes us a step closer to achieving our primary goal of developing a COVID-19 vaccine with a good efficacy and safety profile.”
Roger Connor, President of GSK Vaccines added: “We are pleased to be starting this new Phase II study. The world needs multiple vaccines and we are confident that combining our proven pandemic adjuvant system with this improved antigen formulation will have significant potential as the pandemic evolves. We look forward to further progressing this vaccine candidate to Phase III in Q2 2021, if this Phase II study is successful.”
In parallel to the new Phase II study and recognising the global emergence of new SARS-CoV-2 variants and their potential impact on vaccine efficacy, Sanofi has commenced development work against new variants which will be used to inform the next stages of the Sanofi/GSK development programme.
About the Phase II study
The new Phase II trial is a randomised, double-blind, multi-centre dose finding study conducted in adults aged 18 years of age and older to evaluate the safety, reactogenicity, and immunogenicity of two injections given 21 days apart. The trial will include equal numbers of adults 18 to 59 years and those 60 years and above.
Three different antigen doses with a fixed dose of adjuvant will be tested in a total study population of 720 volunteers, in the United States, Honduras and Panama. Results of the Phase II trial will inform the Phase III protocol.
In December 2020, Phase I/II study results showed an immune response comparable to patients who had recovered from COVID-19 in adults aged 18 to 49 years, but a lower immune response in older adults, likely due to an insufficient concentration of the antigen. If data from the new Phase II trial are positive, a global Phase III study is planned for Q2 2021. Positive results from the Phase III study would lead to regulatory submissions in the second half of 2021, with the vaccine expected to be available in Q4 2021, if approved.