Medicago says Covid-19 Vaccine Shows High efficacy
Canada’s first homegrown COVID-19 vaccine has shown high efficacy against infection during Phase 3 clinical trials, the drugmakers behind the plant-based shot reported Tuesday, fuelling hopes it could soon get a stamp of approval for use.
Medicago, which is headquartered in Quebec, reported in a news release that their Phase 3 placebo-controlled study — conducted in more than 24,000 subjects in six countries who are 18 and older — reported an overall vaccine efficacy rate of 71 per cent against all variants of SARS-CoV-2 which were circulating at the time of the study.
“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,” the release states.
The company says there were no serious adverse events, and side effects were generally mild to moderate.
Despite the success of already authorized doses from the likes of Pfizer and Moderna, the vaccine race isn’t over. If green-lit by Health Canada, the plant-based dose would be the fifth shot to be authorized by the federal regulator, but the first to be developed by a Canadian company.
As the battle against the pandemic continues, company leadership is hopeful that their shot will be another addition to the arsenal. The shot is relatively quick to produce and can be stored in normal refrigerator temperatures, just like the easy-to-transport AstraZeneca dose.
The Phase 2/3 study has a multi-portion design to confirm that the chosen formulation and dosing regimen of the vaccine candidate (two doses of 3.75 µg of antigen combined with GSK’s pandemic adjuvant given 21 days apart) has an acceptable vaccine profile in healthy adults 18-64 years of age, elderly subjects aged 65 and over and adults with comorbidities.
The Phase 2 portion of the trial was a randomized, observer-blind, placebo-controlled study to evaluate the safety and immunogenicity of the adjuvanted recombinant COVID-19 plant-based vaccine candidate in subjects aged 18 and above. It was conducted in multiples sites in Canada and the United States in a population composed of healthy adults (18-64y), elderly adults (over 65y) and adults with comorbidities. Each age group enrolled up to 306 subjects randomized 5:1 to receive the adjuvanted vaccine candidate: placebo and with 2:1 stratification in older adults (65-74 and ≥75). All subjects are being followed for a period of 12 months after the last vaccination for assessment of safety and the durability of the immune responses which will be the final analysis.
The Phase 3 portion of the trial was launched on March 16th, 2021, and was an event-driven, randomized, observer-blinded, crossover placebo-controlled design that evaluated the efficacy and safety of the vaccine candidate formulation, compared to placebo, in over 24,000 subjects across Canada, United States, United Kingdom, Mexico, Argentina, and Brazil.
The data communicated are Per-Protocol, meaning only data from participants who followed the protocol throughout the study are included. A parallel Intention to Treat (ITT) analysis that considers the treatment received by all participants, without regard to protocol adherence yielded very similar results.
The vaccination regimen calls for two doses (3.75 microgram of antigen in combination with GSK’s pandemic adjuvant) given intramuscularly 21 days apart. The vaccine is stored at 2 °C to 8 °C, enabling the use of traditional vaccine supply and cold chain channels.