ABSTRACT
BACKGROUND: Patients with immunodeficiency-associated antibody disorders are at a higher risk of prolonged/persistent COVID-19 infection, having no viable treatment options. METHODS: A retrospective analysis of patients with primary and/or secondary immunodeficiency-associated antibody disorders who received casirivimab and imdevimab (REGEN-COV®) under emergency compassionate use. Objective were to describe safety and response to REGEN-COV, focusing on the subset of patients who had COVID-19 duration ≥21 days before treatment. RESULTS: Quantitative (change in oxygenation status and/or viral load) and/or qualitative (physician-reported clinical status) outcomes data are reported from 64 patients. Improvement in ≥1 outcome was observed in 90.6% of the overall patient group. Thirty-seven of these had COVID-19 duration ≥21 days before treatment; median time from diagnosis to REGEN-COV treatment was 60.5 days. Of the 29 patients with COVID-19 duration ≥21 days before treatment and available outcome data, 96.6% showed improvement in ≥1 outcome. In the 14 patients with post-treatment reverse transcription-polymerase chain reaction (RT-PCR) results available, 11 (78.6%) reported a negative RT-PCR following treatment, with 5 (45.5%) and 8 (72.7%) patients reporting a negative RT-PCR within 5 days and 21 days of treatment, respectively. Ten of 85 patients (11.8%) experienced serious adverse events; only one was an infusion-related reaction, possibly related to REGEN-COV. Two deaths were reported; neither were attributed to REGEN-COV. CONCLUSIONS: In this retrospective analysis of immunodeficient patients granted REGEN-COV under emergency compassionate use, REGEN-COV treatment was associated with rapid viral clearance and clinical improvement in patients with longstanding COVID-19. Adverse events were consistent with COVID-19 and its associated complications, and due to patients' concurrent medical conditions.