Phase 1: To evaluate the safety and tolerability of REGN10933+REGN10987 compared to placebo. To evaluate the virologic efficacy of REGN10933+REGN10987 compared to placebo in reducing viral load of SARS-CoV-2
Phase 2: To evaluate the virologic efficacy of REGN10933+REGN10987 compared to placebo in reducing viral load of SARS-CoV-2
Phase 3: To evaluate the clinical efficacy of REGN10933+REGN10987 compared to placebo as measured by COVID-19-related hospitalizations or all-cause death. To further characterize the concentrations of REGN10933 and REGN10987 in serum over time.
On September 29, 2021, the New England Journal of Medicine reported the results of this study.
REGEN-COV was efficacious across various subgroups, including patients who were SARS-CoV-2 serum antibody–positive at baseline. Both REGEN-COV doses reduced viral load faster than placebo; the least-squares mean difference in viral load from baseline through day 7 was −0.71 log10 copies per milliliter (95% confidence interval [CI], −0.90 to −0.53) in the 1200-mg group and −0.86 log10 copies per milliliter (95% CI, −1.00 to −0.72) in the 2400-mg group. Serious adverse events occurred more frequently in the placebo group (4.0%) than in the 1200-mg group (1.1%) and the 2400-mg group (1.3%); infusion-related reactions of grade 2 or higher occurred in less than 0.3% of the patients in all groups.
REGEN-COV reduced the risk of Covid-19–related hospitalization or death from any cause, and it resolved symptoms and reduced the SARS-CoV-2 viral load more rapidly than placebo.