Evidence-Based Recommendations on the Use of Casirivimab + Imdevimab, and Sotrovimab for Adults in Ontario

Abstract

Critically and Moderately Ill Patients In clinically unstable patients with no history of COVID-19 infection or full vaccination, casirivimab + imdevimab at a dose of 8000 mg IV is recommended if patients are within 9 days of onset of any COVID-19 symptom AND have demonstrated rapid clinical deterioration. Antibody testing is not required in this case. In clinically stable patients with or without a history of COVID-19 infection or full vaccination, casirivimab + imdevimab at a dose of 8000 mg IV may be considered if patients are within 9 days of onset of any COVID-19 symptom AND are not at risk of acute decompensation AND if COVID-19 anti-spike antibody testing demonstrates that they are seronegative. Casirivimab + imdevimab is not recommended for moderately/critically ill patients who are beyond 9 days of onset of any COVID-19 symptom, whether or not they are presumed to have immunity to SARS-CoV-2. Mildly Ill Patients Antibody testing is not required in mildly ill patients. In patients with no history of COVID-19 infection or full vaccination, casirivimab + imdevimab at a dose of 1200 mg intravenous (IV) or subcutaneous (SC) is recommended if patients have confirmed, symptomatic COVID-19 AND are within 7 days of onset of any COVID-19 symptom AND have at least one of the following risk factors: age > 50, obesity, cardiovascular disease (including hypertension), chronic lung disease (including asthma), chronic metabolic disease (including diabetes), chronic kidney disease, chronic liver disease, immunosuppression, or receipt of immunosuppressants. In patients with a history of COVID-19 infection or full vaccination, casirivimab + imdevimab at a dose of 1200 mg IV or SC may be considered if patients have confirmed symptomatic COVID-19 AND are within 7 days of onset of any COVID-19 symptom. In patients with a history of COVID-19 infection or full vaccination with risk factors other than immunocompromise or immunosuppression, SARS-CoV-2 neutralizing antibodies are not recommended as these patients have presumed immunity. In patients with no risk factors, SARS-CoV-2 neutralizing antibodies are not recommended as these patients are at low risk of adverse outcomes. At this time, for mildly ill patients, casirivimab + imdevimab 1200mg IV or SC is preferred over sotrovimab 500mg IV due to practical considerations (i.e. it can also be administered subcutaneously). Ontario’s supply of SARS-CoV-2 neutralizing antibodies is limited, and demand by eligible patients may exceed supply in the near future. Understanding the impact of these agents on patient and system important outcomes will ensure that they are used to greatest benefit. There are clear barriers to allocating SARS-CoV-2 neutralizing antibodies ethically and equitably. A number of strategies are suggested to address these barriers, including optimization of distribution, supply, administration, and allocation, dashboarding, and application of an evidence-informed risk framework for patient selection.