GlaxoSmithKline (GSK) and Medicago’s plant-based COVID-19 vaccine has achieved promising phase 2 trial data, with similar antibody response seen in adults and elderly participants within the study.
The vaccine candidate combines Medicago’s recombinant coronavirus virus-like particles (CoVLP) with GSK’s pandemic adjuvant system. Medicago’s CoVLPs mimic the structure of the SARS-CoV-2 virus that causes COVID-19, which allows them to be recognised and targeted by the immune system.
The phase 2 study, published on the online preprint server MedRxiv, found that the neutralising antibody responses in vaccinated participants were about ten times higher than those seen in a panel of sera from recovering COVID-19 patients.
On top of that, researchers observed similar antibody responses across different age groups, including the 18-64 age group and 65 years and older population.
“We are very excited to see such positive results from the phase 2 data. After two doses, the adjuvanted vaccine candidate induced robust neutralising antibody and cellular immune responses in all subjects, irrespectively of age,” said Nathalie Landry, executive vice president, scientific and medical affairs at Medicago.
GSK and Medicago announced in March that they had started a phase 3 clinical trial evaluating two 3.75 micrograms doses of their COVID-19 vaccine, administered 21 days apart.
Currently, trial sites around the world are enrolling subjects in Canada, the US, the UK and Brazil with further sites to also begin recruiting soon.
“We are delighted to see that the results suggest a very strong immune response. Medicago’s COVID-19 vaccine candidate, combined with GSK’s pandemic adjuvant, was also well tolerated, reinforcing its potential benefits,” said Thomas Breuer, chief medical officer, GSK Vaccines.
“We now look forward to the outcome of the ongoing phase 3 trial of the refrigerator-stable vaccine candidate as the next step forward in our contribution to the global response to the pandemic,” he added.
Earlier this week, GSK also announced positive mid-stage results for its Sanofi-partnered COVID-19 vaccine candidate.
In a phase 2 trial, the immune responses generated by Sanofi/GSK’s adjuvanted recombinant protein-based vaccine were found to be in line with those measured in people who have recovered from COVID-19, the companies said in a statement.
The interim results also showed 95-100% seroconversion following a second injection across all adult age groups in the trial and across all doses.