Medicago, a biopharmaceutical company headquartered in Quebec City, and GlaxoSmithKline announced positive efficacy and safety results from the global Phase 3 placebo-controlled efficacy study of Medicago's plant-based COVID-19 vaccine candidate in combination with GSK's pandemic adjuvant, conducted in over 24,000 subjects, adults 18 years and above, across six countries.

Vaccine efficacy was demonstrated in an environment dominated by SARS-CoV-2 variants, unlike most published Phase 3 efficacy trials for currently licensed COVID-19 vaccines that were conducted when only the ancestral virus was circulating, making direct comparisons impossible. The overall vaccine efficacy rate against all variants of SARS-COV-2 was 71% (95% Confidence Interval: CI 58.7, 80.0; Per Protocol Analysis: PP). The corresponding number for people with an initial seronegative status indicating no previous exposure to COVID-19 was 75.6% (95% CI: 64.2-83.7; PP). The vaccine candidate demonstrated efficacy of 75.3% (95% CI: 52.8, 87.9; PP) against COVID-19 of any severity for the globally dominant Delta variant. Efficacy was 88.6% (95% CI: 74.6, 95.6; PP) against the Gamma variant. Although only a small number of severe cases occurred in this study, none occurred in the vaccinated group. No cases of the Alpha, Lambda and Mu variants were observed in the vaccinated group while 12 cases were observed in the placebo group. The Omicron variant was not circulating during the study.

During the study, no related serious adverse events were reported and reactogenicity was generally mild to moderate and transient; symptoms lasting on average only 1 to 3 days. To date, the Phase 3 results have confirmed the safety profile is consistent with Phase 2 results. The frequency of mild fever was low (<10%), even after the second dose.

Full results of the Phase 3 study will be released in a peer-reviewed publication as soon as possible.

Based on these results, Medicago will imminently seek regulatory approval from Health Canada as part of its rolling submission. The vaccine candidate is not approved yet by any regulatory authorities.

"This is an incredible moment for Medicago and for novel vaccine platforms. The results of our clinical trials show the power of plant-based vaccine manufacturing technology. If approved, we will be contributing to the world's fight against the COVID-19 pandemic with the world's first plant-based vaccine for use in humans," said Takashi Nagao, CEO and President at Medicago. "I want to thank everyone who participated in our clinical trials, our collaborators at clinical trial sites, our partners at GSK, the Government of Canada and Government of Quebec, Mitsubishi Tanabe Pharma Corporation, and all of our employees and our shareholders, for their commitment to advancing vaccine science when the world needs it."