Impact of rituximab on COVID-19 outcomes.

Rituximab is associated with prolonged B-cell depletion and secondary hypogammaglobulinemia and is associated with a dampened humoral response and increased infectious complications. To describe the potential impact of prior rituximab therapy on clinical outcomes from SARS-CoV-2 infection and development of COVID-19 antibodies, we conducted a retrospective study of adults across the Mount Sinai Health System diagnosed with COVID-19 who received rituximab for any indication from February 2019 to October 2020. Patients' baseline characteristics, markers of disease severity, clinical outcomes, and antibody development were examined. Of the 49 patients included in the analysis, 63.2% required hospitalization for COVID-19, 24.5% required an ICU admission, and 32.7% died. Proximity of last rituximab infusion and COVID-19 diagnosis did not affect rates of hospitalization, admission to intensive care units or death. Over half (51.7%) of those whose antibodies were checked developed neutralizing anti-spike protein antibodies. The median time between rituximab administration and COVID-19 diagnosis was not significantly different between those who developed antibodies and those who did not (p = .323). Of the 14 patients with documented negative COVID-19 antibody titers, 11 of them survived SARS-CoV-2 infection, indicating that development of neutralizing antibodies may not be necessary for recovery from COVID-19.