GlaxoSmithKline (GSK) and Vir Biotechnology have secured contracts from the US government for nearly $1bn to supply their Covid-19 antibody treatment, sotrovimab.

Sotrovimab is an investigational single-dose SARS-CoV-2 monoclonal antibody used for the early treatment of Covid-19.

Under the terms of the deal, GSK will be responsible for supplying doses of their Covid-19 vaccine by 17 December this year.

Vir CEO George Scangos said: “Given ongoing evidence, which demonstrates its ability to maintain activity against the tested circulating variants of concern, including Delta, we are confident sotrovimab will continue to be important in the fight against Covid-19.”

The latest order takes the total number of binding agreements secured by the companies for the supply of their Covid-19 vaccine doses to more than 750,000 across the world.

Additionally, the US government will have an option to acquire additional sotrovimab doses through March next year.

GSK chief scientific officer and R&D president Dr Hal Barron said: “Given the large number of patients who continue to become ill with Covid-19 across many regions in the US, there is an ongoing need for access to effective treatments.”

The government’s purchase of sotrovimab doses is funded by the US Department of Health and Human Services Office’s Biomedical Advanced Research and Development Authority.

The therapy received emergency use authorization from the US Food and Drug Administration to treat mild-to-moderate Covid-19 patients aged 12 years and above who are at high-risk disease progression, including hospitalisation or death.

In June this year, GSK and Vir announced final data from the multi-centre, randomised, open-label COMET-TAIL Phase III trial.

The data showed sotrovimab reduced hospitalisation and death risk by 79% in adults with mild-to-moderate Covid-19.