The multivariant COVID-19 vaccine booster underwent its first early study, which began in Manchester in September 2021, and the preliminary findings indicate that it is generating a thorough immune response.
The vaccine has strong levels of neutralizing antibodies, similar to those produced by approved mRNA vaccines, but at up to a 10-fold lower dose in the first 10 individuals, according to preliminary phase one clinical data revealed today (4 January 2022). This information was released by the US-based biotechnology company Gritstone bio, Inc. in collaboration with The University of Manchester and Manchester University NHS Foundation Trust.
The vaccine, which is being tested on 20 healthy adults aged 60 and older who have already received two doses of the first-generation COVID-19 vaccine from AstraZeneca, was generally well-tolerated and safe, according to the results.
The substance, known as samRNA for short, is a self-amplifying mRNA second generation SARS-CoV-2 vaccine that distributes antigens from both spike and non-spike proteins. It is a component of Gritstone’s CORAL program.
The samRNA vaccine significantly increased spike-specific T cells and broad CD8+ T cell responses against targets from conserved SARS-CoV-2 viral proteins.
The trial has been increased to 120 participants in response to the results, which might allow for a quicker transition into a later stage trial.
The trial is being conducted at Manchester Royal Infirmary, a facility run by the National Institute of Health Research that is a component of the Manchester University NHS Foundation Trust (MFT). The MFT Research and Innovation Vaccine Team is conducting the trial. Health Innovation Manchester is helping to fund the trial.
Andrew Allen, M.D., Ph.D., Co-founder, President and Chief Executive Officer of Gritstone, said: “We are thrilled to share that our T cell-enhanced samRNA vaccine from the CORAL program is driving both robust CD8+ T cell responses to a broad array of viral epitopes and strong neutralizing antibody responses to Spike, which we believe validates the potential of our infectious disease platform.
“As we have seen with the Omicron variant, viral surface proteins such as Spike are mutating at a high rate, leaving the immunity provided by Spike-dedicated vaccines vulnerable to variants containing numerous Spike mutations. We designed our COVID-19 vaccines to drive broad CD8+ T cell immunity, an additional key layer of protection against viruses.
“This innovation enables inclusion of a wide array of highly conserved viral epitopes, potentially creating an immune state that may offer more robust clinical protection against current and future SARS-CoV-2 variants and be a first step toward developing a pan-coronavirus vaccine.”
