In yet another move to find a cure to Covid-19, SK bioscience (SK) and GlaxoSmithKline plc (GSK) announced the initiation of Phase 3 clinical study of SK’s Covid-19 vaccine candidate, GBP510, in combination with GSK’s pandemic adjuvant following positive interim Phase 1/2 results.

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

Jaeyong Ahn, CEO, SK Bioscience said, "We are grateful that we were able to advance to the Phase 3 study with the unprecedented support of global initiatives, including GSK, Coalition for Epidemic Preparedness Initiative (CEPI), and the Bill & Melinda Gates Foundation (BMGF). Taking this important step towards overcoming the global pandemic situation, SK and GSK will bring our technical expertise together for the development of an adjuvanted protein-based vaccine candidate, GBP510.”

Thomas Breuer, Chief Global Health Officer, GSK said, “While many countries have made good progress with vaccination, there remains a need for accessible and affordable Covid-19 vaccines to ensure equitable access and to protect people across the world. We are pleased to contribute with GSK’s pandemic adjuvant and to be working with SK to deliver the vaccine at scale via COVAX if it is approved.”

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 are 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.