Efficacy and safety of long-term repeated use of rituximab in pediatric patients with nephrotic syndrome.

Background: We aimed to investigate the efficacy and safety of repeated use of rituximab (RTX) in pediatric patients with nephrotic syndrome (NS). Methods: Retrospective review of 50 patients with steroid-dependent NS (SDNS) who had received more than three cycles of RTX was conducted; each consisted of one to four infusions until B lymphocytes were depleted. Results: The median age of starting the first RTX cycle was 12.4 years (interquartile ranges (IQR) 10.2–14.6). During a median follow-up period of 6.3 (IQR 3.6–8.6) years, patients received a median of 5.0 RTX cycles (IQR 4.0–7.3). The number of relapses decreased from a median of 2.0 relapses per year (IQR 1.0–3.0) to 0.2 relapses per year (IQR 0.0–0.5) after long-term RTX treatments (P < 0.001). Longer relapse-free periods were associated with more than four RTX cycles, longer B-cell depletion, older age at each RTX treatment, and lower cholesterol levels. B lymphocytes recovered to 1% at a median of 5.9 months (95% confidence interval 5.7–6.1) after RTX administration. Factors related to a longer period of B-cell depletion included more than five RTX cycles, a higher dose of RTX, older age at treatment, and concurrent use of antimetabolites. During repeated RTX treatments, 8.0%, 6.0%, and 2.0% of patients developed hypogammaglobulinemia, severe infection, and severe neutropenia, respectively. Conclusions: Long-term repeated use of RTX may be effective and safe in pediatric NS patients. Furthermore, the redosing of RTX could be chosen by considering predictive factors for relapse-free and B-cell depletion periods. [ABSTRACT FROM AUTHOR]