Canadian labs have begun a rolling review of a plant-made COVID-19 vaccine which has generated strong immune reactions within an mid-stage clinical trial. Medicago, located in Quebec City, Canada, declared that after 2 doses, its vaccine candidate, combined together with GlaxoSmithKline’s pandemic oil-based adjuvant AS03, fulfilled its own goals in a stage 2 study. In the randomized, placebo controlled trial, after two doses of this vaccine, known as CoVLP, created neutralizing antibody responses which were about ten times greater compared to patients recovering from the virus. In addition, the vaccine stimulates a cellular immune response of the T helper-2 type (generating interferon-γ and interleukin-4), unlike other COVID-19 vaccines, that excite a T helper-1 reaction. The vaccine was well tolerated, with adverse effects moderate to moderate. Medicago is arriving late to the pandemic vaccine response, but plant-based production retains the advantage it can be rapidly scaled up along with the vaccine, kept between 2 and 8 degrees Celsius, may be helpful in varied environments. Results from phase 1 trials were published 18 May.
Medicago’s platform employs living Nicotiana benthamiana, a relative of tobacco, as a bioreactor to manufacture non-infectious coronavirus-like-particles (CoVLPs). The plants are not genetically modified but transfected with full-length SARS-CoV-2 spike glycoprotein. The recombinant virus-like-particles self-assemble and grass off the plant cell surface, accumulating in the distance between the plasma membrane and the cell wall. The leaves are mixed to extract and purify the VLPs for use from the vaccine. The recombinant VLPs are non-infectious since they lack the virus’s heart hereditary material, but nevertheless provoke an immune response similar to that found in a natural disease.
A stage 3 trial of the vaccine launched in March 2021, and a trial to check the vaccine against emerging variations has also begun. Medicago is collectively owned by Mitsubishi Tanabe Pharma and Philip Morris International.