Early Rituximab as an Add-On Therapy in Children With the Initial Episode of Nephrotic Syndrome.

Introduction: The approximately 70% 12-month relapse in children experiencing the initial episode of steroid-sensitive nephrotic syndrome (SSNS) is a significant concern, with over 50% developing frequent relapses or steroid-dependent nephrotic syndrome (FRNS/SDNS). There is a lack of strategies to reduce relapse after the onset. Whether early administration of rituximab, which effectively reduces relapses in FRNS/SDNS, may be a solution has not been evaluated.

Methods: A prospective, multicenter, open-label, single-arm trial was conducted in China, with a 12-month follow-up. Children aged 1 to 18 years with the first episode of nephrotic syndrome (NS) were screened for eligibility. Proteinuria was evaluated daily using dipsticks. A dose of 375 mg/m of rituximab was intravenously infused within 1 week after achieving corticosteroid-induced remission. The main outcome was 12-month relapse-free survival.

Results: Out of the initially 66 children screened, 44 were enrolled and received rituximab, with all but 1 participant completing the 12-month follow-up. The median age at diagnosis was 4.3 years (interquartile range [IQR]: 3.4-5.9), and 33 (77%) of the participants were male. In the rituximab group, the 12-month relapse-free survival was significantly higher compared to historical controls (32 of 43 [74.4%] vs. 10 of 33 [30.3%];  < 0.001; hazard ratio [HR], 3.76; 95% confidence interval [CI], 1.80-7.81). The analysis revealed a higher 24-month relapse-free survival and a lower incidence of FRNS/SDNS at the 12-month follow-up. Treatment with rituximab was well-tolerated.

Conclusion: Our findings support that early administration of rituximab may be associated with a higher 12-month relapse-free survival and a reduced incidence of FRNS/SDNS in children experiencing the initial episode of SSNS.