Clinical Course and Outcomes of COVID-19 Infection in Patients Treated with Rituximab: A Tertiary Care Center Experience.

Introduction: Patients receiving rituximab (RTX) may be at increased risk for severe Coronavirus infections and worse outcomes compared with the general population. Because of the conflicting results concerning the effect of RTX on the clinical course and outcomes of COVID-19 infection, we aimed to share our experience with 35 patients infected with COVID-19 while treated with RTX for a variety of clinical indications.

Methods: This was a single-centre retrospective cohort study that included 35 patients. All patients aged ≥14 years who were treated with RTX for various conditions and were found to have COVID-19 infection were included. Patients with poor outcomes or patients with suspected COVID-19 infection were excluded.

Results: The patients' mean age was 42.8 ± 16.3 years with an average BMI of 29.9 ± 11.4 kg/m². Over half (51.4%, n = 18) of the patients received RTX at a dose of 375 mg/m2 with a median frequency of 4 doses. More than a third (37.1%, n = 13) of the patients had hypogammaglobulinemia and 25.7% had low CD19. Over a third (42.9%, n= 15) of the patients required hospitalization and almost a third (25.7%, n = 9) required treatment in the intensive care unit. There was a statistically significant association between intensive care unit admission and age, steroid use, and low CD19. The mortality rate was 25.7%, and it was significantly higher in elderly, diabetics, corticosteroid users, patients who were hospitalized, treated in the intensive care unit, and had low immunoglobin or CD19.

Conclusion: Treatment with RTX seems to be a potential risk factor for unfavorable outcomes in COVID-19 patients. RTX should be used with caution or avoided unless the benefit clearly outweighs the risk.