Medicago Gets Positive Results on Plant-Based COVID-19 Vaccine Using GSK Booster

The world’s first plant-based COVID-19 vaccine just returned positive results in a late-stage study.

The candidate, made by Canadian biopharma Medicago using GlaxoSmithKline’s (GSK) vaccine adjuvant, proved to be 75.3 percent effective against the Delta variant and showed an overall efficacy rate against all variants of 71 percent, the companies said in a joint statement yesterday.  

The candidate wasn't tested against Omicron, as the variant hadn't yet emerged when the trial was underway. Medicago said it started the study in March with approximately 24,000 participants age 18 and older in Canada, the U.S., the U.K., Mexico, Argentina and Brazil.

Medicago and GSK said the vaccine candidate was well-tolerated, with no related serious adverse events reported in the vaccine group.

Medicago will now seek regulatory approval from Health Canada as part of a rolling submission, the company said. It has also initiated the regulatory filing process with the FDA and the UK’s Medicines and Healthcare products Regulatory Agency (MHRA).

Preliminary discussions are also underway with the World Health Organization (WHO) for preparation of a submission, the company said.

Medicago said it has also initiated a phase 1/2 trial in Japan, where it plans to submit for regulatory approval in combination with the phase 2/3 global study results next spring.

“The results of our clinical trials show the power of plant-based vaccine manufacturing technology,” said Takashi Nagao, CEO and president of Medicago. “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.”

Thomas Breuer, GSK’s global COVID-19 adjuvanted vaccines lead and chief global health officer, said the trial’s results are encouraging given that data were obtained in an environment with none of the original SAR-CoV-2 virus circulating, so everything seen in the study is for a  new variant.

“The global COVID-19 pandemic is continuing to show new facets with the current dominance of the Delta variant, upcoming Omicron and other variants likely to follow,” he said. “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.”

Medicago has been developing its plant-based technology for the past 20 years to produce virus-like particles (VLP) for its protein vaccines. VLPs are designed to mimic the native structure of viruses, allowing them to be easily recognized by the immune system.

Because the VLPs lack core genetic material, they are noninfectious and unable to replicate, the company said, adding that VLP vaccines developed using other technologies have been used worldwide for more than 30 years. — Suz Redfearn