The drug, called VIR-7831, is a new treatment for people with mild to moderate illness, and the study was so successful that it was discontinued early.
GSK and its partner, For Biotechnology, intend to seek immediate authorization for emergency use in the United States and approval in other countries, including possibly in the United Kingdom.
Monoclonal antibodies are laboratory-produced molecules that mimic human antibodies.
The global phase 3 clinical trial has its initial analysis based on data from 583 patients admitted to the hospital.
GSK said that VIR-7831 works in two ways – by blocking the virus’ access to healthy cells and also by cleaning infected cells.
A separate laboratory study found that VIR-7831 is effective against the major Covid-19 variants, including the Kent, South African, and Brazilian variants.
VIR-7831 is designed to be administered as a single intravenous (IV) infusion.
Dr Hal Barron, Chief Scientific Officer at GSK, said: ‘We are delighted that this unique monoclonal antibody has been able to provide such a huge benefit to patients.
“We look forward to the opportunity to make VIR-7831 available to patients as soon as possible and to further explore its potential in other institutions.”