Evidence-Based Recommendations on the Use of Anti-SARS-CoV-2 Monoclonal Antibodies (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 having received a full recommended schedule of vaccination, casirivimab + imdevimab at a dose of 2400 mg intravenous (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 having received a full recommended schedule of vaccination, casirivimab + imdevimab at a dose of 2400 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 having received a full recommended schedule of vaccination, casirivimab + imdevimab at a dose of 1200 mg IV or subcutaneous (SC) OR sotrovimab at a dose of 500 mg IV 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, indigenous (First Nations, Inuit, or Metis), 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 who have received a full recommended schedule of vaccination, casirivimab + imdevimab at a dose of 1200 mg IV or SC OR sotrovimab at a dose of 500 mg IV may be considered if patients have confirmed symptomatic COVID-19 AND are within 7 days of onset of any COVID-19 symptom AND are immunocompromised or are taking immunosuppressant medications. In patients with a history of COVID-19 infection or who have received a full recommended schedule of vaccination with risk factors other than immunocompromise or immunosuppression, anti-SARS-CoV-2 monoclonal antibodies (AmAbs) are not recommended as these patients have presumed immunity. In patients with no risk factors, AmAbs are not recommended as these patients are at low risk of adverse outcomes. Post-Exposure Prophylaxis (PEP) Casirivimab + imdevimab at a dose of 1200 mg IV or SC OR sotrovimab at a dose of 500 mg IV is recommended for unvaccinated individuals who are currently hospital in-patients or residing in congregate settings (e.g., long-term care settings, retirement homes, shelters, correctional facilities) who have had a high-risk exposure to SARS-CoV-2 (as determined by an expert in Infection Prevention and Control or Public Health) and who are at high-risk to progress to moderate or severe COVID-19. Determination of using an AmAb for post-exposure prophylaxis should take into account the nature and context of their exposure. Implementation Considerations It is recommended that AmAb therapy be administered to non-hospitalized individuals across Ontario using a hybrid network that includes – but is not limited to – mobile integrated healthcare (MIH) services, community paramedicine (CP), and outpatient infusion clinics. Experience from other jurisdictions suggests that hybrid administration approaches coupled with substantial health care system coordination are required to deliver AmAbs in a timely and equitable fashion to those who are likely to benefit from them. Ontario’s supply of AmAbs 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 equitably and to greatest benefit. There are clear barriers to allocating AmAbs ethically and equitably. A number of strategies are suggested to address these barriers, including optimization of dosing, distribution, supply, administration, allocation, dashboarding, and application of an evidence-informed risk framework for patient selection.