Effectiveness of SARS-CoV-2 Monoclonal Antibody Infusions in High-Risk Outpatients

Piccicacco, Nicholas; Zeitler, Kristen; Montero, Jose; Kumar, Ambuj; Lakshmi, Seetha; Kim, Kami; Wein, David; Vasey, Tiffany; Vasey, Matthew; Oxner, Asa

BACKGROUND: Coronavirus disease 2019 (COVID-19) continues to stress the healthcare system. Neutralizing monoclonal antibodies (MABs) were effective in reducing COVID-19 related hospitalizations and emergency department (ED) visits in their respective clinical trials. However, these results have yet to be reproduced in a practical setting following implementation of current FDA guidance. METHODS: This retrospective cohort study included outpatients with confirmed COVID-19 infection, had mild/moderate symptoms for 10 days or less, and deemed high-risk for severe COVID-19 under FDA’s Emergency Use Authorization (EUA) for MABs. Patients who received either bamlanivimab or casirivimab/imdevimab from 11/18/2020 through 01/05/2021 were included (n=200). This was compared against a control cohort of randomly selected high-risk COVID-19 outpatients who declined or were not referred for MAB during the same period (n=200). The primary outcome was a composite of 29-day COVID-19 related hospitalizations and/or ED visits. Prespecified secondary outcomes included the individual components of the primary endpoint, 29-day all-cause mortality, and serious adverse drug events. RESULTS: Patients treated with MAB were significantly less likely to be hospitalized or visit the ED compared with patients not treated with MAB (13.5% vs. 40.5%; OR=0.23; 95% CI 0.14 to 0.38; p<0.001). The mortality rate was 0% in the MAB group compared with 3.5% in the control group (p=0.02). Only 2 patients receiving MAB experienced a serious adverse event requiring treatment. CONCLUSIONS: Among high-risk COVID-19 outpatients with mild/moderate symptoms, early administration of MABs can potentially reduce the strain on the healthcare system during the current pandemic.