GSK, Medicago Start Phase 2 Trial of Adjuvanted COVID-19 Vaccine

GSK and biopharmaceutical company Medicago recently announced the start of Phase 2/3 clinical trials of its adjuvanted COVID-19 vaccine candidate.

The Coronavirus-Like Particle COVID-19 Vaccine Candidate (CoVLP) is composed of recombinant spike (S) glycoprotein expressed as virus-like particles (VLPs).

CoVLPs mimic the structure of the virus responsible for COVID-19 disease, GSK said. This allows them to be recognized by the immune system response and reduce the amount of antigen required per dose.

Medicago’s decision to advance CoVLP to the next phase of clinical trials was based on positive Phase 1 trial results which showed high immune responses in infected patients. 

“We are delighted with the very promising Phase 1 results of Medicago’s COVID-19 vaccine candidate in combination with GSK’s pandemic adjuvant,” Thomas Breuer, chief medical officer, GSK, said in the announcement “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.”

The Phase 2/3 clinical trials will be split up into two trials. 

First, the Phase 2 randomized, placebo-controlled clinical trial will evaluate the safety and immunogenicity of CoVLP in healthy adults aged 18 to 64. Each group will contain over 300 individuals. 

Then before the end of 2020, the companies plan to initiate a Phase 3 trial to evaluate the safety and efficacy of CoVLP in 30,000 subjects in North America, Latin America, and Europe. 

Ultimately, researchers will look to confirm that CoVLP’s specific formulation and dosing regimen, combined with GSK’s pandemic adjuvant, has immunogenicity and a safety profile in adults 18-64 years of age and individuals 65 and older.

The trial will follow all subjects for a period of 12 months after the last vaccination to assess the safety and durability of the immune responses to the vaccine candidate, GSK said. 

The companies expect to be able to manufacture approximately 100 million doses of the candidate by the end of 2021. And by the end of 2023, the companies expect a large-scale facility under construction in Canada to deliver up to 1 billion doses annually. 

GSK and Medicago announced their collaboration in mid-July 2020. The companies committed to developing and evaluating COVID-19 vaccine candidates combining Medicago’s recombinant CoVLP with GSK’s pandemic adjuvant system.

The use of an adjuvant system can be beneficial during a pandemic because it can help to boost immune response and reduce the amount of antigen required per dose, GSK officials said in the July press release. 

The companies then launched a Phase 1 clinical trial in mid-Summer. 

“Our Phase 1 results of the adjuvanted vaccine candidate were very encouraging and fully support further clinical evaluation,” said Nathalie Landry, executive vice president of scientific medical affairs at Medicago.

CoVLP differs significantly from some of the frontrunners in the vaccine race, including the Pfizer-BioNTech partnership, which is  using an mRNA vaccine approach. 

Last week, Pfizer and BioNTech announced that their mRNA-based COVID-19 vaccine candidate, BNT162b2, was found to be more than 90 percent effective in preventing COVID-19 in participants without evidence of prior SARS-CoV-2 infection in a Phase 3 clinical trial.

“We are reaching this critical milestone in our vaccine development program at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen,” Albert Bourla, MD, Pfizer chairman and CEO, said in the announcement.