Sanofi and GSK advance COVID-19 vaccine to late-stage trial

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Sanofi and GSK have announced they will advance their two-shot adjuvanted recombinant COVID-19 vaccine to a phase three clinical trial.

The companies announced the late-stage trial after the candidate achieved "strong rates of neutralizing antibody responses" in a phase two study involving over 700 adults.

"The Phase 2 interim results showed 95% to 100% seroconversion following a second injection in all age groups (18 to 95 years old) and across all doses, with acceptable tolerability and with no safety concerns," said the companies.

"Overall, the vaccine candidate elicited strong neutralizing antibody levels that were comparable to those generated by natural infection, with higher levels observed in younger adults (18 to 59 years old). After a single injection, high neutralizing antibody levels were generated in participants with evidence of prior SARS-CoV-2 infection, suggesting strong potential for development as a booster vaccine."

The companies said the phase three trial is expected to enrol more than 35,000 adult participants from a range of countries and will assess the efficacy of two vaccine formulations including two variants of COVID-19.

“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.”

Roger Connor, the president of GSK Vaccines, added, “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.”