QUEBEC (BLOOMBERG) - GlaxoSmithKline and Medicago said their Covid-19 vaccine candidate spurred protective antibody levels 10 times higher than in patients who have recovered from the disease in interim trial results.
The vaccine generated similar immune responses in all age groups with no serious safety events in the mid-stage trial, Medicago said on Tuesday (May 18) in a statement.
About 500 participants aged 18 to 88 received the vaccine, and about 100 got placebo shots.
The partners are hoping to supply needed shots within months for a global effort that increasingly appears to lack ammunition, with many middle- and low-income nations seeking immunizations.
Advocates are pleading for supplies in particular for India, where a deadly surge is claiming some 4,000 lives daily.
Advanced-stage trials for the plant-based vaccine started in March with volunteers enrolled in Canada, the US, the UK and Brazil.
The companies aim to recruit as many as 30,000 subjects, collect efficacy data this summer and apply for authorization later this year, according to Ms Nathalie Charland, Medicago's senior director of scientific and medical affairs.
The partners "believe that we can be part of the answer against this pandemic. Of course we're not the first to cross the line, but there's eight billion people on the planet," Ms Charland said in an interview.
"We're working on different formulations for different variants also."
Glaxo Partnerships Medicago will determine which variants subjects were infected with during the trial and how well the vaccine protects against them, Ms Charland said.
Lab testing showed good potential against variants, she said.
The vaccine is being tested in a two-dose regimen three weeks apart.
Younger adults produced a stronger response after one dose than adults 65 and older, but the reactions were similar between age groups after two doses, according to the Canadian company.
The development is good news for Glaxo, which also reported positive data from a second mid-stage trial with Sanofi this week. That partnership faced delays last year after a dosing error led to a weak immune response in tests in older people.
Glaxo Chief Executive Officer Emma Walmsley is under pressure after activist fund Elliott Management built a stake in the drugmaker.
The company is hoping to prove it chose the right strategy at the start of the pandemic by using its adjuvants - substances designed to enhance immune responses - to partner with other drugmakers rather than creating its own shot.
UK-based Glaxo is also working with South Korea's SK Bioscience on a Covid vaccine and has committed to helping Novavax and CureVac manufacture theirs, should they be successful.
The company is also working on a second-generation inoculation with CureVac, which reported positive preclinical data last week.
The shot will raise the profile of Medicago's plant-based approach to vaccines and therapeutics.
The plants, derived from tobacco, make non-infectious virus-like particles to spur an immune response. The company is backed by Mitsubishi Tanabe Pharma and Philip Morris International Inc.
A key advantage of the technology is the ease of scaling up production by growing more of the particle-making plants. The company is awaiting approval for a plant-based seasonal flu vaccine from Canada's health regulator.
