Indications, efficacy and safety of rituximab in childhood-onset systemic lupus erythematosus: a retrospective study of the JIR cohort.

Objectives: Childhood-onset systemic lupus erythematosus (cSLE) is a rare autoimmune disease with significant morbidity. Although B cell-depleting agents show promise for refractory cSLE, there is limited research on rituximab therapy in children. This study aimed to retrospectively assess the indications, efficacy, and safety of RTX in cSLE, using data from the Juvenile Inflammatory Rheumatism (JIR) cohort database.

Methods: A national retrospective study analysed data from the JIR cohort for cSLE patients treated with RTX from July 2009 to June 2023.

Results: Forty-one patients received RTX over 14 years; 85.4% were girls and mean age at diagnosis was 11.7 years. RTX was administered on average 16 months post-diagnosis. At treatment initiation, 87% either had received or were receiving corticosteroids, 21% NSAIDs and 82% immunosuppressants. Main indications for RTX were lupus nephritis (51.2%), persistent polyarthritis (19.5%) and refractory cytopenias (12.2%). Significant improvements in disease activity were observed at 3 and 6 months post-RTX infusion, indicated by the SLEDAI-2K score (P < 0.001), along with a notable reduction in corticosteroid usage (from 0.93 mg/kg to 0.39 mg/kg; P = 0.001) and improvements in relevant biomarkers. Adverse effects occurred in 17% of patients, with 7.3% experiencing anaphylactic reactions. One year following the last infusion, 52.5% of the paediatric subjects did not necessitate an increase in their baseline immunosuppressive therapy or the initiation of a novel treatment modality.

Conclusions: RTX in refractory cSLE reduced disease activity and steroid dependence with an acceptable safety profile. Further research and international collaboration are needed to validate these findings.