SARS-CoV-2 Neutralizing Monoclonal Antibodies for the Treatment of COVID-19 in Kidney Transplant Recipients

Background: Morbidity and mortality associated with coronavirus disease 2019 (COVID-19) infection in kidney transplant recipients are high and early outpatient interventions to prevent progression to severe disease are needed. SARS-CoV-2 neutralizing monoclonal antibodies including bamlanivimab and casirivimab-imdevimab received emergency use authorization in the United States in November 2020 for treatment of mild to moderate COVID-19 disease. Methods: We performed a retrospective analysis of 27 kidney transplant recipients diagnosed with COVID-19 between July 2020 and February 2021 who were treated with bamlanivimab or casirivimab-imdevimab and immunosuppression reduction. We additionally identified 13 COVID-19 infected kidney transplant recipients with mild to moderate disease at presentation who did not receive monoclonal antibodies and had SARS-CoV-2 serology testing available. Results: There were no deaths or graft failures in either group. Both infusions were well tolerated. Four of the 27 monoclonal antibody treated patients required hospitalization due to COVID-19 infection. Four of 13 patients who did not receive monoclonal antibodies required hospitalization due to COVID-19 infection. Patients who received monoclonal antibodies demonstrated measurable anti-SARS-CoV-2 IgG with angiotensin-converting enzyme 2 (ACE2) receptor blocking activity at the highest level detectable at 90 days post-infusion, whereas ACE2 blocking activity acquired from natural immunity in monoclonal antibody untreated group was weak. Conclusions: Bamlanivimab and casirivimab-imdevimab combined with immunosuppression reduction were well tolerated and associated with favorable clinical outcomes in kidney transplant recipients diagnosed with mild to moderate COVID-19 disease.