Medicago and GlaxoSmithKline’s (GSK) plant-derived COVID-19 vaccine has generated some promising mid-stage trial results, the companies revealed today.

Interim results from a Phase II trial evaluating the vaccine candidate, which is being tested in combination with GSK’s pandemic adjuvant, found that neutralising antibody responses were ten times higher in vaccinated participants compared to people recovering from COVID-19.

In addition, similar antibody responses were observed in both adults (aged 18-64 years) and the elderly (aged 65 and older) after two doses.

The companies also reported that no related severe adverse events were seen in the trial and that reactogenicity was generally mild-to-moderate and short in duration.

“We are very excited to see such positive results from the Phase II 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.

“These results give us confidence as we continue to move forward with our Phase III clinical trial. We hope to add another tool in the global fight against COVID-19, particularly as cross-protection emerges as an important consideration in vaccination efforts worldwide,” she added.

In March, GSK and Medicago launched a Phase III trial of the vaccine candidate, with trial sites currently enrolling participants in Canada, the US, the UK and Brazil.

They are also expecting additional sites to be added in the ‘coming weeks’, the companies said in a statement.

“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. We now look forward to the outcome of the ongoing Phase III trial of the refrigerator-stable vaccine candidate as the next step forward in our contribution to the global response to the pandemic,” said Thomas Breuer, chief medical officer, GSK Vaccines.