Canadian-made, plant-based COVID-19 vaccine sees positive Phase 3 results

CTV National News: Canadian-developed vaccines The first COVID-19 vaccines developed in Canada are showing promising results. Avis Favaro reports.

TORONTO — Biopharmaceutical company Medicago and drug maker GlaxoSmithKline reported Tuesday positive efficacy and safety results from the Phase 3 trial of their plant-based COVID-19 vaccine.

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.

In an interview with CTV News, Executive Vice-President of Innovation Development and Medical Affairs for Medicago, Marc-Andre D’Aoust, said the study ended up being focused entirely on COVID-19 variants.

“In our efficacy analysis, we have not seen any cases of the original strain of COVID-19…so the results show the vaccine is efficacious against all of those variants we have observed during the study,” he said.

The vaccine uses plant-based technology to create “virus-like particles,” (VLP) which are designed to mimic the structure of viruses so that the immune system can recognize them and build an antibody response to them. VLP do not contain core genetic materials, which makes them non-infectious and unable to replicate.

D’Aoust said it only takes Medicago “days” to produce the vaccine from the moment they have the virus sequence in researchers’ hands.

“So for a new virus, for example, once we have the sequence, in 19 days, we've found that we can produce a research-grade VLP which is the structure of the vaccine that we're using…from there, we can continue with the development and that's what we did for the COVID-19 vaccine development early in 2020,” he explained.

Medicago’s vaccine demonstrated 75.3 per cent efficacy against COVID-19 of any severity for the Delta variant, which D’Aoust said is the most widely circulated strain, and 88.6 per cent efficacy against the Gamma variant.

A small number of severe cases of COVID-19 were observed in the study, but none occurred in the vaccinated group, Medicago said in the release.

“These results are great, these results show the vaccine is efficacious,”D’Aoust said. “We’ve developed [our] technology for 20 years now, and over the last two years we’ve developed a COVID-19 vaccine and these results show that the plant-based platform that we have used to produce the vaccine can produce an efficacious vaccine.”

No cases of the Alpha, Lambda, or Mu variants were observed in the vaccinated group while 12 cases were observed in the placebo group, the release states.

The Omicron variant was not circulating during the study, but D’Aoust said in the interview that Medicago is already analyzing the new strain.

“We're currently evaluating the cross reactivity of the antibodies raised by our current vaccine against Omicron,” he said, adding that the company has “taken action” in case a change is needed in their vaccine in light of the variant.

The Phase 3 study reported no serious adverse events and reactions were “generally mild to moderate and transient,” with symptoms lasting on average from one to three days.

The full results of the Phase 3 study will be released in a peer-reviewed publication, and Medicago will “imminently” seek Health Canada approval based on the Phase 3 results as part of its rolling submission.

“If approved by authorities, this vaccine will be the first plant-based vaccine to be used in humans,” D’Aoust said. “We’re very proud…[because] it will also be the first vaccine to be developed in Canada.”

Professor of Virology and Immunology at Memorial University Nfld., and Vice President of the Canadian Society for Virology Rod Russell told CTV News in an interview Monday that he was not surprised at news of Medicago’s positive results.

“It’s really good that this is an alternative…I like the idea that it’s a different type of platform [plant-based] which is good for hesitancy,” Russell said. “We’re going to need different vaccines or a range of vaccines…so my reaction to the trial data is encouraging.”

Russell noted that Canada “experienced a delay” in access to vaccines at the beginning of the pandemic partly because none were being made domestically.

“So the fact that we’ll have vaccines made in Canada that’s a good thing…it cuts down on supply chain issues” he said of Medicago. “If we start seeing variant specific vaccines at some point again….we could switch right away and start making the new sequence, as fast as other companies do.”

“So this is good news for sure,” Russell said.