First plant-based vaccine for Covid-19
Canadian company Medicago and British company GlaxoSmithKline (GSK) have announced the start of a Phase III clinical trial of their COVID-19 vaccine candidate, a plant-based vaccine from Medicago combined with GSK's pandemic adjuvant. Medicago has received approval from Canadian and US regulatory authorities to continue enrolling healthy adults in the Phase III portion of the trial, based on positive results from the interim Phase II trial.
What's new about this vaccine is that it's plant-based, combined with GSK's pandemic adjuvant. It uses a different technology than other vaccines: it employs live plants as bioreactors (controlled biological environments that generate or produce certain reactions) to create a non-infectious particle that mimics the virus it aims to neutralize. It's known as a "virus-like particle" (VLP).
The Canadian pharmaceutical company is a pioneer in plant-derived therapies and, on this occasion, is using Nicotiana benthamiana plants, a relative of tobacco that has a weakened immune system, meaning that the genetic material can be accepted rather than rejected by the plant. This experimental host is the most widely used in plant virology (mainly due to the large number of viruses that can successfully infect it).
The first step is to create the necessary protein particle and introduce it into a plant-specific bacterial vector. The plants then absorb and multiply the vector. The "mini-bioreactors" They only take between four and six days to produce the "virus-like particles" (VLPs); the company emphasizes that the plants "are not genetically modified, but rather their natural cellular processes are used." The genetic modification used is temporary, not stable as in traditional transgenic crops.
The FDA's decision to grant 'Fast Track' designation to Medicago's vaccine candidate will help accelerate efforts to bring the first plant-based Covid-19 vaccine to market.
The vaccine would be administered in two doses 21 days apart and would also have the advantage of being refrigerated, which could be key for developing countries. that do not have the resources to store doses that must be kept at ultra-cold temperatures.
To date, Canada has authorized four COVID-19 vaccines: the mRNA vaccines from Moderna and Pfizer/BioNTech, and the viral vector vaccines from AstraZeneca and J&J. The plant-based Medicago platform offers a unique candidate for several reasons: it is versatile, because the platform can produce both vaccines and antibodies. And it is easy to scale up manufacturing, because the same cultivation conditions are required whether it is one plant or 10,000.
Medicago has begun the application process with Health Canada to obtain authorization for its COVID-19 vaccine candidate derived from genetically modified plants, currently in Phase III trials. If approved, they would be ready to produce 80 million doses by the end of 2021 and double that amount in 2022.
Ramona Ávila Núñez, PhD
Source: https://www.biopharma-reporter.com/Article/2021/04/27/Medicago-s-plant-based-COVID-19-vaccine-starts-Health-Canada-rolling-review