Remarks

• With benefits of casirivimab-imdevimab observed only in patients with seronegative status, clinicians will need to identify these patients by credible tests available at the point of care to appropriately apply this recommendation (see Evidence to Decision section).
• Treatment with casirivimab-imdevimab is in addition to the current standard of care, which includes corticosteroids and IL-6 receptor blockers.

Practical Info Dosing and administration route: Intravenous dosing of the monoclonal antibody combination in the RECOVERY trial that enrolled severe and critical COVID-19 was a total dose of 8000 mg (4000 mg for each antibody), whereas the dose differed in the four trials in non-severe patients (from a larger adaptive randomized master protocol), ranging from intravenous total dose of 1200 mg–8000 mg. In the face of limited access and resource considerations, health systems will face a choice concerning the dose of casirivimab-imdevimab. Please see the acceptability and feasibility section (under Evidence to Decision) for deliberations to help in making these choices within the possible range of 2400 mg–8000 mg total dose. Diagnostic testing: Tests to identify patients with seronegative status at the time patients present with severe or critical COVID-19 warrant rapid serological tests with adequate performance characteristics. Health care systems would need to implement such tests, as outlined in the acceptability and feasibility section. Monitoring: Although the available trials have not convincingly shown that casirivimab-imdevimab results in allergic reactions, the possibility remains. Administer through an intravenous line containing a sterile in-line or add-on 0.2 micron filter. Following infusion, patients should undergo monitoring for allergic reactions.