New research published in the New England Journal of Medicine found that a combination of the monoclonal antibodies casirivimab and imdevimab, REGEN-COV, significantly reduced the risk of COVID-19–related hospitalizations and death in patients. The study results were part of the phase 3 portion of an adaptive trial.
In the cohort receiving the REGEN-COV antibody combination, 18 out of 1,355 patients (1.3%) experienced COVID-10–related hospitalization or death from any cause over a period of 28 days after treatment. In the placebo group, 62 out of 1,341 patients (4.6%) were reported to have COVID-19–related hospitalization or death.
Researchers said the antibody drug combination also resolved symptoms and reduced COVID-19 viral load more rapidly than a placebo. The median time to resolution of symptoms was 4 days shorter with each REGEN-COV dose than with placebo. Additionally, the antibody combination was efficacious across various subgroups, including patients who were SARS-CoV-2 serum antibody-positive at baseline.
The study authors write: “Previous data from the phase 1-2 portion of this trial showed that in outpatients with COVID-19, REGEN-COV lowered the viral load, reduced the need for medical attention related to COVID-19, and may have reduced the risk of hospitalization. The phase 3 clinical outcomes data presented here are consistent with and strengthen these findings showing that early use of REGEN-COV in outpatients with risk factors for severe COVID-19 can lower the risk of hospitalization or death from any cause.”
The trial was funded by Regeneron Pharmaceuticals, the maker of the drug cocktail.