Rituximab in Childhood Steroid-dependent Nephrotic Syndrome: A Single-center Experience

Background: Most children with idiopathic nephrotic syndrome are steroid-sensitive. However, the majority of them relapse. Unfortunately, 50–70% of relapsers will develop frequently relapsing nephrotic syndrome or steroid-dependent nephrotic syndrome (SDNS). This study focused on the effect and safety of rituximab in childhood SDNS. Methods: This retrospective study included SDNS children who received rituximab from 1/1/2021 to 30/6/2023. Data were collected about age at onset of nephrotic syndrome, age at first rituximab dose, and details of infusions. Time till CD19+B cell repletion and time till relapse post-rituximab, as well as total dose of steroids given per year and duration of remission, one year before and one year after rituximab, were analyzed. Results: Thirty SDNS patients received rituximab treatment at a median age of 9.75 years for the first dose. During a median follow-up period of 19 months, only 16.7% developed complications, mostly allergic reactions, and 47.6% of patients relapsed. No significant correlation was observed between the time till CD19+ B-cell reconstitution and the time till relapse. A significant positive correlation was found between the time till relapse post-rituximab and the duration of nephrotic syndrome before rituximab. However, no similar correlation was found with the age at the first rituximab dose or renal biopsy findings. The total steroid dose (per year) was significantly lower, and the duration of remission was significantly longer in the year after rituximab compared to the year before. Conclusion: Rituximab significantly prolongs the duration of remission and decreases the total steroid doses needed. There is a positive correlation between the time till relapse post-rituximab and the duration of nephrotic syndrome before rituximab. There is no significant difference in relapse incidence with or without routine prophylactic rituximab retreatment after B-cell repletion.