Casirivimab and imdevimab in patients admitted to hospital with COVID-19 (RECOVERY): A randomized, controlled, open-label, platform trial

The LancetHorby PW, Mafham M, Peto L, et al. | February 14, 2022


In this study, use of casirivimab and imdevimab (monoclonal antibodies) in combination in patients hospitalized for COVID-19 led to decrease in 28-day mortality in those who were seronegative (and thus had not mounted their own humoral immune response) at baseline but not in those who were seropositive at baseline.

  • In this randomized, controlled, open-label platform trial (RECOVERY), patients aged at least 12 years admitted to hospital with clinically suspected or laboratory-confirmed SARS-CoV-2 infection were included.

  • A total of 4,839 patients were randomized to casirivimab and imdevimab plus usual care and 4946 to usual care alone.

  • In the primary efficacy population of seronegative patients, death within 28 days occurred of 24% of patients who received casirivimab and imdevimab vs 30% of patients allocated to usual care (rate ratio [RR] 0·79).

  • In an analysis of all randomly assigned patients (regardless of baseline antibody status), 19% of patients treated with casirivimab and imdevimab vs 21% of patients allocated to usual care died within 28 days (RR 0·94).

  • The proportional impact of casirivimab and imdevimab on death varied significantly between seropositive and seronegative patients.

  • No treatment related deaths occurred, and no meaningful between-group differences existed in the pre-specified safety outcomes of cause-specific mortality, cardiac arrhythmia, thrombosis, or major bleeding events.

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