Covid-19: Regeneron's antibody combination cuts deaths in seronegative patients, trial finds

Regeneron’s antibody combination treatment cut deaths in seronegative patients—meaning those who had not mounted their own antibody response to covid-19—by one fifth, the Recovery trial has found. The researchers found that for every 100 seronegative patients treated with the combination of casirivimab and imdevimab, there were six fewer deaths. They said patients admitted to hospital should now be routinely tested for antibodies to determine whether the treatment could benefit them. The two virus neutralising antibodies work by binding non-competitively to the critical receptor binding domain of SARS-CoV-2’s spike protein, thereby stopping the virus from binding to and entering human cells. Recovery, which is being carried out in 177 UK hospitals, has been evaluating potential covid-19 treatments for patients admitted to hospital. It discovered the first effective treatment for reducing mortality—dexamethasone—while also discounting others including hydroxychloroquine and convalescent plasma.