A possible new coronavirus vaccine candidate produced by Sanofi and GSK (GlaxoSmithKline) that uses the human body’s own antigens to neutralize antibody responses for people who have already recovered from the illness, has completed Phase 2 trials, the companies said Monday.
The candidate is expected to begin Phase 3 trials in the coming weeks, they added.
Interim results show between 95% and 100% success after the second injection of the vaccine in candidates age 18-95, along with no reported safety concerns, the study said.
In addition, the vaccine reportedly elicited strong neutralizing antibody levels comparable to those generated by natural infection – with higher levels seen in younger adults in the 18-59 age range.
Following a single injection of the vaccine, the study showed, high neutralizing antibody levels were generated in participants who showed prior COVID-19 infection, which suggests a strong potential for developing the Sanofi and GSK vaccine as a booster vaccine.
"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," said Thomas Triomphe, executive vice president and global head of Sanofi Pasteur.
"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," he added.
President of GSK Vaccines Roger Connor said, "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. 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."
Following their positive Phase 2 interim results, the companies now plan to start a global Phase 3, randomized, double-blind study, in the coming weeks. The trial is expected to enroll more than 35,000 adult from several countries and will assess the efficacy of two vaccine formulations including the D614 (Wuhan) and B.1.351 (South African) variants.
At the same time, the companies plan to conduct booster studies with various variant formulations to see if a lower dose of the vaccine may be used to generate a strong booster response regardless of the initial vaccine platform received.
Pending positive results from the Phase 3 testing and regulatory reviews, the vaccine is expected to be approved in the fourth quarter of 2021.