On Aug. 31, 2021, SK bioscience and GlaxoSmithKline announced the initiation of a Phase 3 clinical study of SKﾒs COVID-19 vaccine candidate, GBP510, in combination with GSKﾒs pandemic adjuvant following positive interim Phase 1/2 results.

The randomised, active-controlled global trial planned to enrol around 4,000 participants from a range of countries and will aim to evaluate GBP510ﾒs safety and immunogenicity compared to an active comparator – the AstraZeneca/Oxford University COVID-19 vaccine. The study was one of the first global Phase 3 trials to compare two different COVID-19 vaccine candidates.

The advance to Phase 3 study follows positive interim Phase 1/2 data which showed that all participants who received the adjuvanted vaccine candidate developed strong neutralizing antibody responses, demonstrating a 100% seroconversion rate. Neutralizing antibody titres were between five and a maximum of eight times higher compared to sera from people recovered from COVID-19. No safety concerns have been identified to date in this ongoing study.

GBP510 is a self-assembled nanoparticle vaccine candidate targeting the receptor binding domain of the SARS-CoV-2 Spike protein, combined with GSK’s pandemic adjuvant. The antigen is being developed by SK in collaboration with the Institute for Protein Design (IPD) at the University of Washington with support from BMGF and CEPI as part of the ‘Wave 2’ vaccine investment project to develop more accessible and affordable COVID-19 vaccines.

Results from the Phase 3 study were expected in the first half of 2022 after which, subject to positive results and regulatory approval, the vaccine is expected to be supplied at scale worldwide through the COVAX facility.