GSK and Canadian biopharma Medicago are joining forces on the development and evaluation of a COVID-19 candidate vaccine combining the former's recombinant Coronavirus Virus-Like Particles (CoVLP) with GSK’s pandemic adjuvant system.

CoVLPs mimic the structure of the virus responsible for COVID-19 disease, allowing them to be recognised by the immune system.

As adjuvants can boost the immune response and lessen the dose required they can be of particular importance in a pandemic situation, as they enable more vaccine doses to be produced.

Based on promising preclinical results of the vaccine, which demonstrated a high level of neutralising antibodies following a single dose when administered with adjuvant, Phase I clinical testing is scheduled to begin mid-July to assess the safety and immunogenicity of three different dose levels of antigen combined with GSKs pandemic adjuvant and in parallel with an adjuvant from another company.

The companies are hoping to complete development and make the vaccine available in the first half of 2021, using Medicago’s highly-scalable, plant-based production platform to manufacture the COVID-19 vaccine antigen, combined with GSKs proprietary adjuvant system.

The companies expect to be able to manufacture approximately 100 million doses by the end of 2021 and, by the end of 2023, a large-scale facility under construction in Quebec City, Canada, is expected to deliver up to 1 billion doses a year.

“This agreement paves the way for an innovative vaccine option combining a scalable plant-based antigen technology with an adjuvant which has pandemic dose sparing capability. If successful, it will be a meaningful contributor in the fight against COVID-19,” said Dr Thomas Breuer, chief medical officer, GSK Vaccines.

“We strongly believe that multiple vaccines are needed, including post-pandemic vaccines. This plant-based technology also shows promise beyond COVID-19 and has the potential to help prevent other infectious diseases.”