First plant-based coronavirus vaccine shows ‘positive’ results, say GlaxoSmithKline and Medicago

The global Phase 3 placebo-controlled efficacy study used Canada-based Medicago’s plant-based vaccine in combination with British drugmaker GSK’s pandemic adjuvant, an ingredient that works to boost the immune response and efficacy of others’ vaccines.

It does not yet have a brand name, the companies said, but is currently referred to as “CoVLP.”

Plant-based vegan and vegetarian alternatives in food and materials markets have become increasingly popular globally, as consumers choose them for environmental or religious reasons, but Brian Ward, medical officer at Medicago, told The Washington Post that it would not be appropriate to categorize the vaccine candidate as such: “The plants that are used simply act as bioreactors to produce the antigen.”

The companies said they hoped the vaccine would diversify the current pool of shots available and said the trial had shown that it was “well-tolerated, with no related serious adverse events reported in the vaccine group.”

“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,” Takashi Nagao, CEO and president of Medicago, said in a statement. “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.”

The vaccine candidate has not been approved by any regulatory authority.

However, Medicago said it would “imminently” file its final regulatory submission to Health Canada. It also said it had initiated the regulatory filing process with the U.S. Food and Drug Administration and Britain’s MHRA regulatory authority, while preliminary discussions were also underway with the World Health Organization.

The WHO previously called plant-based vaccines, made by producing antigens in genetically modified plants that can then be extracted and purified by conventional methods, a “new and exciting possibility.”

“Plant-derived vaccines have several advantages,” the WHO said, including being “produced cheaply in very high amounts,” using carrier plants such as potatoes and corn. The antigens created “are stable and can be stored for long periods of time,” it said, adding that “the likelihood that contamination by a plant virus would have an adverse effect on humans is almost negligible.”

GSK’s chief global health officer, Thomas Breuer, called the results “encouraging” in a statement, especially as coronavirus variants emerge.

“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,” he said.

Quebec-based Medicago has been developing its plant-based technology for the past 20 years, it said, producing “Virus-Like Particles” for its protein vaccines — which it describes as akin to creating empty shells. The particles mimic the structure of viruses, allowing them to be easily recognized by the immune system and induce an immune response similar to a natural infection. But because they lack core genetic material, they are noninfectious and unable to replicate.

Medicago said its vaccination regimen calls for two doses given intramuscularly 21 days apart and for the vaccine to be stored at 36 to 46 degrees Fahrenheit (2 to 8 degrees Celsius).