Positive Phase 3 Efficacy and Safety Results for Adjuvanted Plant-Based COVID-19 Vaccine Candidate
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% 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 one to three 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 yet approved by any regulatory authority.
“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, all of our employees and Mitsubishi Tanabe Pharma Corporation, for their commitment to advancing vaccine science when the world needs it.”
Thomas Breuer, GSK’s global COVID-19 adjuvanted vaccines lead and Chief Global Health Officer, said, “These are encouraging results given data were obtained in an environment with no ancestral virus circulating. The global COVID-19 pandemic is continuing to show new facets with the current dominance of the Delta variant, upcoming Omicron, and other variants likely to follow. The combination of GSK’s established pandemic adjuvant with Medicago’s plant-based vaccine technology has significant potential to be an effective, refrigerator-stable option to help protect people against SARS-CoV-2.”
Medicago has been developing its plant-based technology for the past 20 years, using unique technology to produce Virus-Like Particles (VLP) for its protein vaccines. VLPs are designed to mimic the native structure of viruses, allowing them to be easily recognized by the immune system. Because the VLPs lack core genetic material, they are non-infectious and unable to replicate. VLP vaccines developed by other technologies have traditionally been used worldwide for more than 30 years.
“I am pleased to see our vaccine candidate moving forward and bringing to the world the first plant-based vaccine against COVID-19, diversifying the pool of vaccines available to help improve public health and protect more people,” said Yosuke Kimura, Chief Scientific Officer at Medicago.
Medicago has initiated the regulatory filing process for the adjuvanted plant-based COVID-19 vaccine candidate with the FDA (US) and the MHRA (UK). Preliminary discussion is underway with the WHO for preparation of the submission. Medicago has also initiated a Phase 1/2 trial in Japan where it plans to submit for regulatory approval in combination with the Phase 2/3 global study results next spring.