Medicago and GlaxoSmithKline (GSK) have reported positive interim Phase II clinical trial safety and immunogenicity data for Medicago’s plant-derived Covid-19 vaccine candidate, which has been tested in combination with GSK’s pandemic adjuvant.
These results are part of the ongoing Phase II/III study and reiterate the promising profile observed during Phase I testing. Immunogenicity, as measured by the neutralising antibody titre, was about 10 times higher than those in a panel of sera from patients recovering from Covid-19. No related severe adverse events were reported and 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 neutralizing antibody and cellular immune responses in all subjects, irrespective 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.”
Thomas Breuer, Chief Medical Officer, GSK Vaccines said: “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 this refrigerator-stable vaccine candidate as the next step forward in our contribution to the global response to the pandemic.”
The Phase III trial of the vaccine candidate launched on March 16, 2021. Trial sites are currently enrolling subjects in Canada, the United States, the United Kingdom and Brazil, with additional sites expected to be added. The vaccine candidate has received Fast Track designation by the FDA in the US, and Health Canada has initiated a review of Medicago’s Covid-19 rolling submission under the Interim Order.
The Phase II/III study is a multi-portion design to confirm that the chosen formulation and dosing regimen of CoVLP (two doses of 3.75 µg CoVLP combined with GSK’s pandemic adjuvant given 21 days apart) has an acceptable immunogenicity and safety profile in healthy adults 18-64 years of age, elderly subjects aged 65 and over and adults with comorbidities.
The Phase II portion of the trial was a randomised, observer-blind, placebo-controlled study to evaluate the safety and immunogenicity of the adjuvanted recombinant Covid-19 plant-derived vaccine candidate in subjects aged 18 and above. It was conducted in multiples sites in Canada and the US in a population composed of healthy adults (18-64 years), elderly adults (over 65 years) and adults with comorbidities. Each age group enrolled up to 306 subjects randomised 5:1 to receive the adjuvanted CoVLP vaccine candidate: placebo and with 2:1 stratification in older adults (65-74 and ≥75). All subjects will be followed for a period of 12 months after the last vaccination for the assessment of safety and durability of the immune responses to the vaccine candidate which will be the final analysis.