Rituximab as a first-line therapy in children with new-onset idiopathic nephrotic syndrome.

Background: Idiopathic nephrotic syndrome (INS) in children, commonly treated with steroids, poses challenges due to associated side effects. Rituximab, known for its efficacy in reducing relapse frequency in difficult-to-treat cases, emerges a potential first-line therapy for pediatric new-onset INS.

Method: This is a single-center, retrospective, observational study to evaluate the efficacy and safety of rituximab as a first-line therapy for pediatric INS. The complete treatment strategy was weekly injections at a dose of 375 mg/m² for four doses. Children with new-onset INS who received rituximab as a first-line monotherapy from 1 January 2022 to 31 December 2023 were included and followed until 31 May 2024.

Results: Seventeen patients (median age at diagnosis 4.8 years) were included. Twelve patients achieved complete remission within a median time of 19 days. Over a follow-up period ranging from 41 to 112 weeks, 11 patients maintained remission even after B-cell reconstitution, with one patient experiencing a relapse at 85 weeks. Three patients, who presented with hematuria, hypocomplementemia or renal injury at initial diagnosis, exhibited resistance to rituximab. No severe adverse events were noted.

Conclusion: Rituximab may be an effective and safe option as a first-line therapy for inducing and maintaining remission in newly diagnosed INS.