South Korea-based SK bioscience has plans to conduct a global Phase III clinical trial of its Covid-19 vaccine candidate, GBP510, which yielded positive interim results in a Phase I/II trial.

Developed in partnership with the Institute for Protein Design (IPD) at the University of Washington in the US, GBP510 is a recombinant protein antigen vaccine adjuvanted using GlaxoSmithKline’s (GSK) pandemic adjuvant system.

An interim analysis of the vaccine’s Phase I/II trial revealed favourable immunogenic response and safety profile in the stage 1 part involving 80 healthy adults at multiple sites.

Data showed a 100% seroconversion rate, with all GBP510-vaccinated subjects showing the production of neutralising antibodies against SARS-CoV-2.

SK bioscience added that the neutralising antibody titre was five to up to eight times greater than human sera from patients who recovered from Covid-19.

In addition, data revealed no vaccine-related serious adverse events.

The company already concluded second dosing for 247 subjects in stage 2, including elderly participants, and is continuing a follow-up study. No notable safety concerns were reported to date.

In a statement, SK bioscience said: “Based on the positive interim data from Phase I/II clinical trial, SK bioscience has received approval from South Korea’s Ministry of Food and Drug Safety (MFDS) for its Phase III investigational new drug (IND) application.

“This is the first-ever MFDS Phase III IND approval for a domestically developed Covid-19 vaccine and SK bioscience is initiating the final stage of the clinical study with the goal of making it available in the first half of 2022.”

The company has entered a cross-border collaboration to conduct the Phase III trial.

Development costs related to the vaccine are being supported by the Bill & Melinda Gates Foundation (BMGF) and Coalition for Epidemic Preparedness Innovations (CEPI), which is funding the Phase III trial.

The Phase III programme will be performed by the International Vaccine Institute (IVI).

IVI will run the Phase III trial across multiple regions, including Europe and South-East Asia while SK bioscience will prepare for WHO Pre-qualification certification and emergency use authorisations.

The Phase III trial will be conducted at 14 sites in South Korea alone.

Furthermore, IVI and SK bioscience signed an agreement with the Korea National Institute of Health (KNIH) to jointly perform antibody testing in Phase III trial participants.