The efficacy of rituximab in pediatric patients with steroid-dependent or frequent relapsing nephrotic syndrome due to MCD or FSGS.

Background: Rituximab has been shown efficacy in reducing relapses among patients with steroid-dependent or frequently relapsing nephrotic syndrome (SDNS/FRNS), primarily due to minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS). However, whether its efficacy differs between these two histological subtypes remains unclear. Methods: A retrospective cohort study included 42 pediatric SDNS/FRNS patients with biopsy-proven MCD or FSGS. Clinical outcomes, including remission rates and relapse frequency were assessed. Results: The median age at diagnosis of the 42 patients was 5.1 years (IQR: 2.9-7.4), and 28 (67%) patients were male during the 6-year follow-up. Each patient received a median of 4 (IQR: 3-5) infusions. All patients achieved clinical remission, with 90.5% attaining complete remission. Relapse times decreased to 35.7% within 1 year after the first rituximab treatment, from a median of 2 relapses to 0. No significant difference in relapse rates was observed between patients receiving 3-4 doses versus 1-2 doses during the initial course. Histologically, 36 patients (85.7%) had MCD and 6 (14.3%) had FSGS. In the FSGS group, the 96-month relapse-free survival was higher compared to MCD controls (2/6 [33.3%] vs. 15/36 [41.7%]; Conclusion: Rituximab is effective for SDNS/FRNS children, whatever MCD or FSGS. These findings support repeated rituximab use in SDNS/FRNS. However, given the small sample size of the FSGS subgroup, these findings should be interpreted with caution and require validation in larger, multicenter studies.