Plant-based COVID-19 vaccine enters Phase I trials

Medicago announced it has started Phase I trials of its plant-derived COVID-19 vaccine. The company, which uses virus-like particles (VLPs) in its vaccines, rather than animal products or live viruses, has dosed the first healthy volunteer.

According to the enterprise, VLPs have a multi-modal mechanism of action that works differently to inactivated vaccines, by activating both antibody and cell-mediated responses.

The COVID-19 vaccine candidate in testing, a recombinant coronavirus VLP (CoVLP), will be tested in a randomised, partially blinded study of 180 normal healthy subjects aged 18-55. It will evaluate three dosages – 3.75, 7.5 or 15 micrograms and the vaccine will be either administered on its own or with an adjuvant in a prime-boost regimen.

The adjuvants that will be used alongside the CoVLP vaccine candidate are GlaxoSmithKline’s pandemic adjuvant technology and Dynanvax’s CpG 1018.

Last week, GSK and Medicago signed a deal to jointly develop and evaluate the CoVLP candidate, with the companies agreeing to share the cost of development and manufacturing if it proves to be effective in human subjects.

In preclinical testing, CoVLP demonstrated the ability to induce the production of a high level of antibodies following a single adjuvanted dose. Adjuvants are thought to be particularly useful in pandemic situations, as they can boost immune response and reduce the amount of antigen required per dose, allowing more vaccine doses to be manufactured and distributed.

The company said that dependent on the results, it envisions a large-scale Phase II/III trial beginning as early as October and expects to be able to manufacture around 100 million doses by the end of 2021. Following the completion of its large-scale facility in Quebec City, Canada, in 2023, the company expects to have capacity to produce up to one billion doses of its COVID-19 vaccine annually.

“Creating a sufficient supply of COVID-19 vaccines within the next year is a challenge that will require multiple approaches, with different technologies,” said Dr Bruce Clark, president and chief executive officer of Medicago.

Medicago has already completed a Phase III clinical trial of a quadrivalent VLP influenza vaccine candidate and Phase II clinical trials of a H1N1 pandemic vaccine candidate, both using its plant-based manufacturing technology. The company’s flu vaccine is currently under review with Health Canada, following the completion of a safety and efficacy clinical programme in over 25,000 subjects.