On Mar. 4, 2021, the NIH announced that the ACTIV-3 clinical trial evaluating the safety and efficacy of investigational therapeutics for COVID-19 in hospitalized patients, had closed enrollment in two sub-studies: one examining the investigational monoclonal antibody therapy VIR-7831, and another evaluating the investigational combination monoclonal antibody therapy containing BRII-196 and BRII-198.

The sub-studies were halted by the trial sponsor, the NIAID) part of the National Institutes of Health, on Mar. 1, 2021, following an interim review and recommendation from the independent Data and Safety Monitoring Board (DSMB).