Remarks

• Whereas casirivimab-imdevimab achieves a substantial reduction in the relative risk of hospitalization, the absolute benefit will be trivial in absolute terms for all but those at highest risk for which the intervention should be reserved.
• The panel identified a risk beyond 10% of being hospitalized for COVID-19 to represent a threshold at which most people would want to be treated with casirivimab-imdevimab.
• In the absence of credible tools to predict risk for hospitalization in people infected with COVID-19, typical characteristics of people at highest risk include lack of vaccination, older people, or those with immunodeficiencies and/or chronic diseases (e.g. diabetes).

Practical Info Dosing and administration route: Intravenous total dose of the monoclonal antibody combination differed in the non-severe trials, ranging from total dose 1200 mg–8000 mg (600 mg–4000 mg each antibody), demonstrating efficacy at all doses, including the lowest tested, 1200 mg total dose (600 mg of each antibody). In the face of limited access and resource considerations, health systems will face choices concerning dose of casirivimab and imdevimab as well as intravenous or subcutaneous injections. Please see the acceptability and feasibility section (under Evidence to Decision) for some deliberations to help in making these choices within the possible range of 1200 mg–2400 mg total dose. Monitoring: Although the available trials have not convincingly shown that casirivimab and imdevimab results in allergic reactions, the possibility remains. To be administered through an intravenous line containing a sterile in-line or add-on 0.2 micron filter. Following administration, patients should undergo monitoring for severe anaphylaxis.