Casirivimab-Imdevimab Treatment Is Associated with Reduced Rates of Hospitalization Among High-Risk Patients with Mild to Moderate Coronavirus Disease-19

Abstract

Background: Real-world clinical data to support the use of casirivimab-imdevimab for the treatment of outpatients 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. \n \nMethods: 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. \n \nFindings: The median age of the antibody-treated cohort was 63 years (interquartile range, 52-71); 45·5% 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 (1·2% vs 3·4%; Odds Ratio [OR], 0·26; 95% confidence interval (CI): 0·11-0·64), day 21 (1·2% vs 4·2%; OR, 0·22; 95% CI: 0·09-0·52), and day 28 (1·3% vs 4·9%; OR, 0·21; 95% CI: 0·09-0·48). Rates of intensive care unit admission and mortality at days 14, 21 and 28 were similarly low for antibody-treated and untreated groups. \n \nInterpretation:Among high-risk patients with mild to moderate COVID-19, casirivimab-imdevimab treatment was associated with a significantly lower rate of hospitalization. \n \nFunding Information: This work was funded by an intramural grant from Mayo Clinic to RRR. \n \nDeclaration of Interests: CP, AP, AV, and PL are employees of nference and have financial interests in the company. JCO is supported by grants from nference, and is a paid consultant for Elsevier, Inc. and Bates College. ADB is supported by grants from NIAID (grants AI110173 and AI120698) Amfar (#109593) and Mayo Clinic (HH Shieck Khalifa Bib Zayed Al-Nahyan Named Professorship of Infectious Diseases). ADB is a paid consultant for Abbvie and Flambeau Diagnostics, is a paid member of the DSMB for Corvus Pharmaceuticals and Equilium, owns equity for scientific advisory work in Zentalis and Nference, and is founder and President of Splissen therapeutics. RRR is supported by research grants from Regeneron, Roche, Gilead and the Mayo Clinic, and is a member of DSMB for Novartis. All other have nothing to disclose. \n \nEthics Approval Statement: The Mayo Clinic Institutional Review Board approved this study. Informed consent was waived and patients without research authorization were excluded.