Sanofi, GSK begin Phase 3 clinical study to chart safety, efficacy of COVID-19 vaccine candidate

Another COVID-19 vaccine may soon be on the way: Sanofi and GSK began enrollment for a phase three, global clinical study of their adjuvanted recombinant-protein vaccine candidate, with the anticipation it could be approved by the end of the year.

Approval will, of course, depend on results, and the phase three study will chart the vaccine’s safety, efficacy, and immunogenicity. More than 35,000 volunteers, either 18 years old or older, will be enrolled from the U.S. and various countries in Asia, Africa, and Latin America. The trial will be randomized, double-blind, and placebo-controlled and organized around two stages. During these stages, vaccine formulations will be tapped to target the original SARS-CoV-2 virus and the B.1.351 variant originally identified in South Africa.

“We are encouraged to see first vaccinations starting to take place in such an important, pivotal Phase 3 study, as we believe that our unique technology platform will provide a clinically relevant vaccine option,” Thomas Triomphe, executive vice president and Global Head of Sanofi Pasteur, said. “We have adapted our vaccine development strategy based on forward-looking considerations as the virus continues to evolve, as well as anticipating what may be needed in a post-pandemic setting. This trial is testament to the urgency and agility in our approach to help overcome the ongoing impact of this pandemic.”

Further, a booster study program will begin in the near future to complement the ongoing trial and to assess the vaccine’s capability to generate a strong response regardless of any initial vaccine platform a participant may receive.

“We believe further solutions for COVID-19 are very much needed to help reach people around the world, especially as the pandemic evolves and variants continue to emerge,” Roger Connor, president of GSK Vaccines, said. “Adjusting our technology and study designs reflects this need and will further build the potential of this adjuvanted protein-based vaccine. We are grateful to the volunteers who will take part in the trials and hope the results will add to the encouraging data we’ve seen so far so we can make the vaccine available as quickly as possible.”

In interim phase two results, the vaccine candidate was already shown to produce high rates of neutralizing antibody responses among all adult age groups, boasting 95-100 percent seroconversion rates.

With support from the Biomedical Advanced Research and Development Authority (BARDA) and the U.S. Department of Defense Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense, the candidate is made through a combination of Sanofi’s recombinant antigen and GSK’s pandemic adjuvant platform. Manufacturing should begin in weeks, the companies report, to support anticipated approval.