Efficacy and Safety of Rituximab in Preventing Clinical Relapse in Pediatric-Onset Multiple Sclerosis: An Observational Cohort Study

Abstract

Background: Pediatric-onset multiple sclerosis (POMS) presents unique therapeutic challenges, including higher relapse rates and earlier disability accumulation than adult-onset multiple sclerosis. Objectives: This study aimed to evaluate the efficacy and safety of rituximab for preventing clinical relapses in children with POMS. Methods: We conducted an observational cohort study of pediatric patients with relapsing POMS who received rituximab between April 2018 and March 2024. Baseline demographic, clinical, laboratory, and neuroimaging data were retrospectively extracted from medical records. Patients were subsequently followed from the date of rituximab initiation, and information on clinical relapses and treatment-related adverse events was collected via medical-record review and structured telephone follow-up. Results: The study included 34 pediatric patients (17 female and 17 male). The median age at diagnosis was 11 years (range, 4 - 17 years). During a median follow-up of 36 months (range, 12 - 60 months), 26.5% of patients experienced at least one relapse, resulting in an annualized relapse rate (ARR) of 0.11 (95% CI, 0.07 - 0.20). Temporal analysis showed that 80% of relapses occurred within the first 18 months after rituximab initiation, and no relapses were observed among patients who completed 5 years of follow-up. Baseline neurological examination findings, including reduced muscle force (P < 0.001), abnormal deep tendon reflexes (P < 0.001), extensor plantar responses (P < 0.001), and sensory dysfunction (P = 0.03), were significantly associated with an increased risk of relapse. Rituximab demonstrated a favorable safety profile, with 41.2% of patients experiencing mild, transient adverse effects, predominantly cutaneous reactions (20.6%) and gastrointestinal symptoms (8.8%). No serious infections, anaphylaxis, or treatment discontinuations occurred. Conclusions: In this study, rituximab was associated with a low observed ARR and predominantly mild, transient adverse effects, with no serious safety signals during follow-up. Specific baseline neurological findings were associated with an increased risk of relapse and may inform future risk-stratification efforts. These findings are observational and hypothesis-generating; larger prospective, controlled studies are needed to confirm efficacy and safety and define rituximab's role in POMS treatment algorithms.