The first results of an early trial of a multivariant COVID-19 vaccine booster, launched in Manchester in
US-based biotechnology company
Results also show the vaccine, which is being trialled with the anticipated involvement of 20 people aged 60 and over, who were in good health and previously received two doses of
Part of Gritstone's CORAL program, the compound is a self-amplifying mRNA second generation SARS-CoV-2 vaccine - or samRNA for short - which delivers antigens from both spike and non-spike proteins.
The samRNA vaccine also produced broad CD8+ T cell responses against targets from conserved SARS-CoV-2 viral proteins and boosted spike-specific T cells.
Based on results, the trial is now being expanded to 120 people, potentially enabling more rapid advancement into a later stage trial.
The trial is taking place within the
'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.'
A single 10 -microg dose of the CORAL programme's samRNA vaccine dose administered at least 22 weeks after two doses of the
New CD8+ T cell responses across a wide set of non-spike epitopes, including many validated T cell targets in convalescent individuals, demonstrating the potential for variant-proof immunity
A boost to pre-existing T cell responses to Spike epitopes (assessed by ELISpot) believed to be additive to antibody-based clinical protection conferred by Spike-dedicated vaccines Broad and potent neutralizing antibodies against SARS-CoV-2 Spike protein, at levels consistent with published data from higher doses of first-generation mRNA vaccines in a similar clinical context (COV-BOOST study; Munro et al.,
It also demonstrated a well-tolerated safety profile with no grade 3/4 adverse events or unexpected safety events.
Professor
'We are excited to announce the expansion of the footprint of this trial from an initial 20 people to 120 and are looking forward to continuing this work with Gritstone in the clinical development of this promising next generation, T cell enhanced COVID-19 vaccine.
'It is increasingly apparent that a focus on T cell immunity is an important way to generate the robust and durable immunity that may prevent future SARS-CoV-2 variants from causing severe disease, hospitalisation, and death.'
He added: 'We know the immune response to first generation vaccines can wane, particularly in older people. Coupled with the prevalence of emerging variants, there is a clear need for continued vigilance to keep COVID-19 at bay.
'We believe this vaccine, as a booster, will elicit strong, durable, and broad immune responses, which may well be likely to be critical in maintaining protection of this vulnerable elderly population who are particularly at risk of hospitalisation and death.'
(C) 2022 Electronic News Publishing, source