Positive interim Phase 2 results for COVID-19 vaccine from Medicago and GSK

Topline findings from interim Phase 2 trial results include:

• All subjects who received an adjuvanted vaccine candidate developed significant antibody and cellular immune responses after two doses
• Similar antibody responses were observed in adults and in the elderly
• There were no severe adverse events reported
• The reactogenicity events were generally mild to moderate and short in duration

Phase 3 trials of the vaccine candidate got underway in March, with trial sites in Canada, US, Brazil, and the UK, and addition study locations to come on stream in the coming weeks. 

“We are very excited to see such positive results from the Phase 2 data. After two doses, the adjuvanted vaccine candidate induced robust neutralizing antibody and cellular immune responses in all subjects, irrespectively of age,​” said Nathalie Landry, executive vice president, scientific and medical affairs at Medicago. “These results give us confidence as we continue to move forward with our Phase 3 clinical trial." ​

Thomas Breuer, chief medical officer, GSK Vaccines, said the results suggest a very strong immune response. "Medicago’s COVID-19 vaccine candidate combined with GSK’s pandemic adjuvant was also well tolerated, reinforcing its potential benefits. We now look forward to the outcome of the ongoing Phase 3 trial of this refrigerator-stable vaccine candidate as the next step forward in our contribution to the global response to the pandemic.”​

The vaccine candidate has received Fast Track designation by the FDA in the US, and Health Canada has initiated a review of Medicago’s COVID-19 rolling submission under the Interim Order. 

Plant-derived therapeutics​

Founded in 1999, Quebec City’s Medicago is a pioneer of plant-derived therapeutics.

Its tech takes the idea of traditional vaccine manufacturing – based on using eggs to produce viruses – and instead uses living plants as the bioreactor that produces a protein particle that mimics the target virus.

The first step is to create the required protein particle and introduce it into a plant-specific bacterial vector. This is then taken up by plants which multiplies the vector. It takes just four to six days for the ‘mini-factories’ to produce the Virus-Like-Particles (VLPs) – compared to around six months for egg-based production (The company highlights that plants are not genetically modified; rather, the plants’ natural cellular processes are used).

While initial experiments had used alfalfa, today the company uses N. benthamiana​ plants: a relative of tobacco which has a weakened immune system meaning genetic material can be hosted rather than rejected by the plant.

Its work on its COVID-19 vaccine candidate started in February last year.

“We were able to produce a VLP after just 20 days of having the genetic sequence,”​ Landry told BioPharma-Reporter​​ last month.

“As we had been working on other vaccine candidates, it was not difficult for us to pivot and apply the technology to our COVID-19 candidate.”​

The COVID-19 candidate uses Coronavirus-Like-Particle (CoVLP) technology with the vaccine composed of recombinant spike (S) glycoprotein expressed as virus-like-particles (VLPs) co-administered with GSK’s pandemic adjuvant.  Two doses are administered 21 days apart (3.75 micrograms of CoVLP per dose).