Across all adult age groups, going as high as 95 years old, a phase two trial of the Sanofi and GSK adjuvanted recombinant COVID-19 vaccine candidate has demonstrated high antibody responses and no safety concerns, according to interim data released this week.
Strong immune responses included a 95 percent to 100 percent seroconversion following second injection among the 722 volunteers of the study. Further, neutralizing antibody levels produced were comparable to those generated by natural infection and recovery, with higher levels observed in those between the ages of 18 and 59 years old. Even a single injection provided high antibody levels in participants with evidence of prior SARS-CoV-2 infection, also making a case for the vaccine’s use as a booster.
“Our Phase 2 data confirm the potential of this vaccine to play a role in addressing this ongoing global public health crisis, as we know multiple vaccines will be needed, especially as variants continue to emerge and the need for effective and booster vaccines, which can be stored at normal temperatures, increases,” Thomas Triomphe, executive vice president and Global Head of Sanofi Pasteur, said. “With these favorable results, we are set to progress to a global Phase 3 efficacy study. We look forward to generating additional data and working with our partners around the world to make our vaccine available as quickly as possible.”
That phase three trial will be randomized and double blind, with more than 35,000 participants involved from a range of countries. During that testing, the two different formulations of the vaccine candidate will be tested against the original strain of SARS-CoV-2 and the B.1.351 South African variant. This study should begin soon.
At the same time, booster studies will be undertaken against various variants to assess the ability of lower vaccine doses to generate booster responses, regardless of the initial vaccine issued.
“These positive data show the potential of this protein-based adjuvanted vaccine candidate in the broader context of the pandemic, including the need to address variants and to provide for booster doses,” Roger Connor, president of GSK Vaccines, said. “We believe that this vaccine candidate can make a significant contribution to the ongoing fight against COVID-19 and will move to Phase 3 as soon as possible to meet our goal of making it available before the end of the year.”
If phase three goes well, the candidate could be approved in the fourth quarter of the year.