Casirivimab-Imdevimab treatment is associated with reduced rates of hospitalization among high-risk patients with mild to moderate coronavirus disease-19

Background: Real-world clinical data to support the use of casirivimab-imdevimab for the treatment of out-patients with mild to moderate coronavirus disease-19 (COVID-19) is needed. This study aimed to assess the outcomes of casirivimab-imdevimab treatment of mild to moderate COVID-19. Methods: A retrospective cohort of 696 patients who received casirivimab-imdevimab between December 4, 2020 and April 9, 2021 was compared to a propensity-matched control of 696 untreated patients with mild to moderate COVID-19 at Mayo Clinic sites in Arizona, Florida, Minnesota, and Wisconsin. Primary outcome was rate of hospitalization at days 14, 21 and 28 after infusion. Findings: The median age of the antibody-treated cohort was 63 years (interquartile range, 52-71); 45 cent 5% were >65 years old; 51.4% were female. High-risk characteristics were hypertension (52.4%), body mass index >35 (31.0%), diabetes mellitus (24.6%), chronic lung disease (22.1%), chronic renal disease (11.4%), congestive heart failure (6.6%), and compromised immune function (6.7%). Compared to the propensity-matched untreated control, patients who received casirivimab-imdevimab had significantly lower all-cause hospitalization rates at day 14 (1.3% vs 3.3%; Absolute Difference: 2.0%; 95% confidence interval (CI): 0.5-3.7%), day 21 (1.3% vs 4.2%; Absolute Difference: 2.9%; 95% CI: 1.2-4.7%), and day 28 (1.6% vs 4.8%; Abso-lute Difference: 3.2%; 95% CI: 1.4-5.1%). Rates of intensive care unit admission and mortality at days 14, 21 and 28 were similarly low for antibody-treated and untreated groups. Interpretation: Among high-risk patients with mild to moderate COVID-19, casirivimab-imdevimab treat-ment was associated with a significantly lower rate of hospitalization. . (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Automated summary

This study found that among high-risk patients, treatment with casirivimab-imdevimab was associated with significantly lower hospitalization rates.