The preclinical data was generated through pseudo-virus testing of the combined known mutations of the Omicron variant, which included the maximum number of changes (37 mutations) identified to date in the spike protein, GSK said in a statement.

These findings build on the initial preclinical data generated through pseudo-virus testing, provided last week, showing sotrovimab retained in vitro activity against key individual mutations of the Omicron variant, including those found in the binding site of sotrovimab.

These data add to the growing body of preclinical evidence demonstrating that sotrovimab retains activity against all tested variants of concern.

George Scangos, PhD, Chief Executive Officer of Vir, said: “Sotrovimab is the first monoclonal antibody to report preclinical data demonstrating activity against all tested SARS-CoV-2 variants of concern and interest to date, including Omicron, as well as the still prevalent and highly contagious Delta variant. Given the less than three-fold neutralization shift demonstrated in the pre-clinical pseudo-virus assay, which falls below the FDA authorized fact sheet guidance of less than a 5-fold change, we are confident that sotrovimab will continue to provide significant benefit for the early treatment of patients hoping to avoid the most severe consequences of COVID-19.”

Dr Hal Barron, Chief Scientific Officer and President R&D, GSK, said: “From the outset of our collaboration with Vir we hypothesized that sotrovimab would have a high barrier to resistance and thus could deliver best-in-class potential for the early treatment of patients with COVID-19. These pre-clinical data demonstrate the potential for our monoclonal antibody to be effective against the latest variant, Omicron, plus all other variants of concern defined to date by the WHO, and we look forward to discussing these results with regulatory authorities around the world.”