China-based Clover Biopharmaceuticals has started dosing participants in a Phase I clinical trial of its Covid-19 S-Trimer subunit vaccine candidate, SCB-2019.

The product is based on the company’s Trimer-Tag vaccine technology platform.

The Phase I trial will assess GlaxoSmithKline (GSK)’s pandemic adjuvant system and Dynavax Technologies’ CpG 1018 adjuvant, in combination with alum, as part of Clover’s research partnerships with these companies.

The addition of an adjuvant to certain vaccines is expected to boost immune response, generating a stronger and long-lasting immunity compared to the vaccine alone.

During a pandemic, the use of an adjuvant could decrease the amount of antigen needed per dose and enable the manufacturing of more vaccine doses.

In preclinical studies, adjuvanted SCB-2019 was observed to induce neutralising antibodies in various animal species.

The randomised, double-blind, placebo-controlled Phase I trial will evaluate the safety, reactogenicity and immunogenicity of the vaccine candidate at different dose levels. Each dose level will be analysed with and without the adjuvant.

Being performed at Linear Clinical Research in Perth, Australia, the study will recruit around 90 healthy adults and 60 healthy elderly participants.

Preliminary safety and immunogenicity data from the Phase I trial are expected to be available in August this year. The company is also planning for a global Phase IIb/III efficacy trial of the vaccine by the end of this year.

Clover Biopharmaceuticals CEO Joshua Liang said: “We are pleased to achieve this significant milestone for our Covid-19 vaccine candidate, as the entire Clover team and our collaborators around the world have been working nonstop since late-January on this important programme for the world.

“More than ever, Clover remains focused on developing a safe, effective and accessible Covid-19 vaccine at a scale that could potentially impact the course of the pandemic globally.”

The company received funding from the Coalition for Epidemic Preparedness Innovations (CEPI) to support its Covid-19 vaccine programme, including the Phase I trial.