A phase 2/3 trial evaluating a plant-derived vaccine candidate against coronavirus disease 2019 (COVID-19) has begun.

The adjuvanted coronavirus-like particle (CoVLP) COVID-19 vaccine (Medicago and GlaxoSmithKline) is composed of recombinant spike (S) glycoprotein expressed as virus-like particles developed through plant-based vaccine technology. The phase 2 portion of the trial will assess the safety and immunogenicity of the adjuvanted CoVLP vaccine candidate in healthy adults aged 18 to 64 years and in patients aged 65 and older. Patients will be randomized 5:1 to receive 2 doses of CoVLP (given 21 days apart) or placebo, and with 2:1 stratification in older patients (65-74 years and 75 years or older). The trial will enroll over 300 patients in each age group and will follow patients for 12 months after the last vaccination.

The phase 3 portion of the trial is anticipated to begin before the end of 2020, and will assess the efficacy and safety of the adjuvanted CoVLP vaccine in up to 30,000 patients in North America, Latin America and/or Europe.

The initiation of the phase 2/3 trial was based on positive phase 1 results that showed the adjuvanted CoVLP vaccine candidate elicited a promising antibody response and was well tolerated in all patients after 2 doses. Moreover, preclinical studies of the vaccine demonstrated a high level of neutralizing antibodies following a single dose when administered with adjuvant. 

“Our phase 1 results of the adjuvanted vaccine candidate were very encouraging and fully support further clinical evaluation,” said Nathalie Landry, Executive Vice President, Scientific and Medical Affairs at Medicago.

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The vaccine is being developed using GlaxoSmithKline’s pandemic adjuvant, which is expected to enhance and prolong immune responses. “We are delighted with the very promising phase 1 results of Medicago’s COVID-19 vaccine candidate in combination with GSK’s pandemic adjuvant,” said Thomas Breuer, Chief Medical Officer GSK Vaccines. “Proven dose-sparing and a high immune response due to GSK’s adjuvant make us confident of delivering an efficacious vaccine with an acceptable safety profile in collaboration with Medicago.”

For more information visit medicago.com.


Medicago and GSK announce start of phase 2/3 clinical trials of adjuvanted COVID-19 vaccine candidate. [press release]. Quebec City and London: Medicago and GSK; November 12, 2020.