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Sanofi, GSK start new phase 2 study of COVID-19 vaccine candidate
By Adekunle Yusuf
Two global pharmaceutical giants, Sanofi and GlaxoSmithKline (GSK), have announced the initiation of a new phase 2 study of their adjuvanted recombinant protein COVID-19 vaccine candidate. The study began with 720 volunteers aged 18 and over to select the most appropriate antigen dosage for Phase 3 evaluation
Over the past few weeks, the two teams have worked to refine the antigen formulation of their recombinant-protein vaccine, based on learnings from their initial studies, 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. 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,” Triomphe said.
According to Roger Connor, President of GSK Global Vaccines, the world needs multiple vaccines, which explains why the two pharmaceutical giants have decided to combine resources. “We are pleased to be starting this new phase 2 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 3 in Q2 2021, if this phase 2 study is successful.”
In parallel to the new Phase 2 study and recognising the global emergence of new SARS-CoV-2 variants and their potential impact on vaccine efficacy, Sanofi said it has commenced development work against new variants, which will be used to inform the next stages of the Sanofi/GSK development programme. The new phase 2 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 (property of a vaccine of being able to produce common and expected adverse reactions, especially excessive immunological responses and associated signs and symptoms, including fever and sore arm at the injection site), 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 2 trial will inform the phase 3 protocol. In December 2020, phase 1/2 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 2 trial are positive, a global Phase 3 study is planned for Q2 2021. Positive results from the Phase 3 study would lead to regulatory submissions in the second half of 2021, with the vaccine expected to be available in Q4 2021, if approved.
The advancement of the trial programme is supported by the United States’ Biomedical Advanced Research and Development Authority (BARDA), part of the HHS Office of the Assistant Secretary for Preparedness and Response under contract W15QKN-16-9-1002. Sanofi and GSK’s adjuvanted recombinant protein-based COVID-19 vaccine candidate was selected in July 2020 by the U.S. government in order to accelerate its development and manufacturing.
In the partnership between the two companies, Sanofi provides its recombinant antigen and GSK contributes its pandemic adjuvant, both established vaccine platforms that have proven successful against influenza. The recombinant technology combined with GSK’s adjuvant could offer the advantages of stability at temperatures used for routine vaccines, the ability to generate high and sustained immune responses, and the potential to prevent virus transmission.
GSK’s response to COVID-19 has been one of the broadest in the industry, with two potential treatments in addition to our vaccine candidates in development. GSK is collaborating with several organisations on COVID-19 vaccines by providing access to our adjuvant technology. In addition to work with Sanofi, collaboration with Medicago on an adjuvanted, protein-based vaccine candidate is now in late-stage clinical trials. Earlier stage collaboration with SK Bioscience is also ongoing, with funding from CEPI and Bill and Melinda Gates Foundation, to develop differentiated, affordable COVID-19 vaccines for supply globally through the COVAX facility. The use of an adjuvant can be of particular importance in a pandemic since it may reduce the amount of vaccine protein required per dose, allowing more vaccine doses to be produced, contributing to protecting more people. GSK is also working with mRNA specialist, CureVac, to jointly develop next generation, multi-valent mRNA vaccines for COVID-19 with the potential to address multiple emerging variants in one vaccine. GSK will also support manufacturing of up to 100m doses of CureVac’s first generation COVID-19 vaccine, if approved.
