(411) Safety and Efficacy of Monoclonal Antibodies Against Sars-Cov-2 in a Heart Transplant Population

PURPOSE: The COVID-19 pandemic has been an unprecedented situation, possibly more so for immunocompromised individuals at higher risk for infection and serious complications. While vaccinations are available, immunocompromised patients are unlikely to mount a significant immune response. Monoclonal antibodies for COVID-19, tixagevimab co-packaged with cilgavimab (tix-cil), are available for pre-exposure prevention, but concerning safety data has led limited use in the heart transplant (HT) population. We evaluated the safety and efficacy of tix-cil in a HT population. METHODS: Electronic medical records were reviewed for HT patients who had received tix-cil following FDA emergency use authorization in December 2021. Records were reviewed for vaccination history, confirmed COVID-19 infection, pre- and post-dose panel-reactive antibodies (PRA) and/or donor-specific antibodies (DSA), and complications. RESULTS: A total of 187 patients received at least 1 dose, with 10 receiving 2 doses, from January 2022-September 2022. Mean age at time of first dose was 58.3 (± 14) years and average time from transplant to first dose was 5.2 years (range 9 days to 35 years). Of the 187 patients who received tix-cil, 185 patients (98.9%) were vaccinated prior to receiving their first dose, receiving on average 3.4 vaccine doses prior to their first tix-cil dose. Fifty-four patients (28.9%) had confirmed COVID-19 infection prior to tix-cil dose, while only 16 patients (8.6%) were diagnosed with COVID-19 infection after tix-cil dosing. Only 1 patient (0.5%) had PCR confirmed COVID-19 both pre- and post-tix-cil dosing. Only 2 patients (1.1%) had serious complications within 90-days following dose administration requiring hospitalization. One patient was admitted for suspected rejection in the setting of immunosuppression non-adherence and a second patient was admitted with undifferentiated shortness of breath, felt to be non-cardiac. Of 82 patients who had PRA and/or DSA testing pre- and post-tix-cil dosing, 10 patients (12.2%) had new or increased from prior DSAs. None of these patients developed antibody mediated allograft rejection over the course of follow-up. CONCLUSION: Use of monoclonal antibodies against SARS-COV-2 proved to be safe and effective in a HT population. Longer-term follow-up and multi-center studies are needed to fully assess the impact of these agents on outcomes.