Real world predictors of hypogammaglobulinemia and serious infections in patients receiving ocrelizumab or ofatumumab for the treatment of multiple sclerosis: The REPLACE-MS study

Introduction: Ocrelizumab (OCR) and ofatumumab (OFB) are disease-modifying therapies (DMTs) for multiple sclerosis (MS). Patients on these DMT’s are at higher risk of hypogammaglobulinemia (HGG), which may increase the risk of infections. Objectives: To investigate the impact of OCR and OFB and patient-specific, independent factors in developing HGG and serious infections. Methods: This multicenter, cohort retrospective study included patients who had received induction dosing with OCR or OFB. The primary outcome was the incidence and predictors of HGG. Results: A total of 911 patients (732 OCR, 179 OFB) were included. The mean (±SD) age was 45.4 (±12.8 years), and 68.6% were female. A total of 9.8% of patients developed HGG. Univariate analysis associated older age, Caucasian race, longer time on therapy, and lower baseline immunoglobulin G (IgG) levels as potential risk factors for HGG. Multivariable regression identified age ⩾50 years ( p = 0.039), Caucasian race ( p = 0.0002), and time on therapy ⩾3 years ( p = 0.0094) as independent risk factors for HGG. Eight percent of patients experienced a serious infection. Multivariable regression identified HGG, lymphopenia, time on therapy ⩾3 years, previous DMT use, and progressive phenotype as independent risk factors for serious infection. A propensity-score-matching analysis found no differences in HGG and serious infection rates between OCR and OFB. Conclusions: Age over 50, Caucasian race, time on therapy 3 or more years were risk factors for HGG.