On Jun. 16, 2021, Regeneron announced positive results from the largest trial assessing any monoclonal antibody treatment in patients hospitalized with severe COVID-19. The UK RECOVERY trial found that adding investigational REGEN-COV to usual care reduced the risk of death by 20% in patients who had not mounted a natural antibody response on their own against SARS-CoV-2, compared to usual care on its own.