Predictors of hypogammaglobulinemia and serious infections among patients receiving ocrelizumab or rituximab for treatment of MS and NMOSD

Ocrelizumab and rituximab are monoclonal antibodies targeting the CD20 marker on B lymphocytes. The enhanced efficacy of B lymphocyte depleting therapies poses a greater risk of decreased immunoglobulin (Ig) levels. The rate and risk factors of hypogammaglobulinemia in MS and NMOSD patients treated with anti-CD20 therapies are unknown. A retrospective study was conducted among patients who received anti-CD20 therapy for the treatment of MS, NMOSD, and other related neurological disorders. The goal was to determine the incidence and risk factors of hypogammaglobulinemia and serious infections in patients receiving ocrelizumab versus rituximab. The secondary goals were to determine the rates of lymphopenia, neutropenia, and early B cell repopulation among patients on anti-CD20 therapy. Overall, 184 patients (mean age 48.4 ± 13.7, 66.8% female) met inclusion criteria; 152 patients received ocrelizumab and 32 patients received rituximab. A total of 22 patients (12%) developed hypogammaglobulinemia. Patients who developed hypogammaglobulinemia were more likely to have been ≥50 years of age (p = .0275) with lower baseline IgG (p = .001) and IgA (p = .0038) levels. Serious infections were observed in 21 patients (11%) and seen more commonly in those that developed total lymphopenia (