Tapping GSK tech, Medicago kick-starts later-stage COVID-19 vax tests

GlaxoSmithKline GSK House in Brentford, UK
(GlaxoSmithKline)

After signing up to use GlaxoSmithKline’s adjuvant vaccine technology back in the summer, Canadian biotech Medicago has already finished off a phase1, and is now kicking on with several phase 2/3 trials.

The plant-derived vaccine candidate recently passed unscathed through a phase 1 but will now face the bigger and more important stage, enrolling around 30,000 subjects to assess just how well the vaccine can work, and how safe it can be.

The coronavirus-Like Particle COVID-19 vaccine candidate (CoVLP) is made up of recombinant spike (S) glycoprotein expressed as virus-like particles (VLPs). This differs from some of the frontrunners in the vaccine race, including Pfizer/BioNTech and Moderna, which are using an unapproved mRNA tech.

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Medicago’s study is set up to see whether it’s chosen formulation and dosing regimen of CoVLP (two doses of 3.75 µg CoVLP combined with GSK’s pandemic adjuvant given 21 days apart) will work on a bigger population.

It’s also assessing whether it has an acceptable immunogenicity and safety profile in healthy adults 18-64 years of age and in elderly subjects aged 65 and over.

It’s broken down in two tests: The phase 2 will be a placebo-controlled study of healthy adults (18-64) and elderly adults (over 65), with each age group having more than 300 subjects randomized 5 to 1 get adjuvanted CoVLP vaccine candidate: placebo and with 2 to1 stratification in older adults (65-74 and older than 75).

The phase 3, which “should start before the end of 2020”, the biotech said in a statement, is an event-driven, randomized, observer-blinded, placebo-controlled design that will look at the safety and efficacy in up to 30,000 subjects in North America, Latin America and/or Europe.

“This is the first of several GSK COVID-19 vaccine candidate collaborations to start phase 2/3 clinical testing and an important step forward in our contribution to the global fight against the pandemic,” said Thomas Breuer, CMO of GSK vaccines.

“We are delighted with the very promising phase 1 results of Medicago’s COVID-19 vaccine candidate in combination with GSK’s pandemic adjuvant. 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.”

With emergency authorizations on the near horizon for Pfizer/BioNTech and Moderna’s mRNA vaccines, Medicago will be much further back in the race for a vaccine. But speed may not be the most important element in controlling the pandemic, with a series of vaccines and vaccine technologies needed.   

One of the CoVLP vaccine candidate’s benefits is that it is highly scalable and can potentially be made in large amounts quickly; a must for any vaccine rollout. GSK and Medicago have previously said they foresee making their vaccine available for mid-2021.