GlaxoSmithKline (GSK) and Vir Biotechnology have started dosing participants in a Phase II/III clinical trial of VIR-7831 (GSK4182136) as a potential early treatment for Covid-19 patients at high hospitalisation risk.

VIR-7831 is a fully human anti-SARS-CoV-2 monoclonal antibody developed to bind to an epitope present on the virus. In-vitro, the antibody was able to neutralise SARS-CoV-2 live virus.

Also, the antibody has been designed to boost lung bioavailability.

Named COMET-ICE, the Phase II/III trial will evaluate the ability of the drug candidate to prevent Covid-19-related hospitalisation in about 1,300 patients with early symptomatic infection globally.

The multi-centre, double-blind, placebo-controlled study involves two parts.

In the first Lead-In part, the safety and tolerability of a single 500mg intravenous (IV) dose of VIR-7831 will be compared to placebo over 14 days in approximately 20 non-hospitalised patients in the US.

The second Expansion part will investigate the safety and efficacy of a single IV infusion of the antibody or placebo in approximately 1,300 non-hospitalised patients globally. The aim of this part is to reduce the need for hospitalisation.

Primary efficacy endpoint is the proportion of participants with mild or moderate Covid-19 who progress, determined as the requirement for hospitalisation or death, within 29 days of randomisation.

Initial data from the study are expected before the end of this year and complete results may be reported in the first quarter of next year. Early access to the antibody therapy is anticipated in the first half of next year.

GSK chief scientific officer and R&D president Dr Hal Barron said: “Monoclonal antibodies directed against the SARS-CoV-2 virus could provide an effective and immediate immune response to Covid-19, bypassing the need for our body to produce its own antibodies, which is particularly important in the absence of an effective vaccine.”

The COMET programme for VIR-7831 additionally involves two planned trials for the severely ill hospitalised patients, and the prophylaxis of symptomatic infection.

Later this year, the companies plan to launch a Phase II trial of another SARS-CoV-2 neutralising antibody candidate, VIR-7832.

GSK and Vir partnered in April this year to research and develop treatments for coronaviruses.

In May, GSK announced plans to evaluate rheumatoid arthritis drug otilimab for treating pneumonia caused by Covid-19.