Rituximab therapy for childhood onset idiopathic nephrotic syndrome: experience of a Portuguese tertiary center

INTRODUCTION: Rituximab (RTX) is a therapeutic option in pediatric difficult-to-treat idiopathic nephrotic syndrome (NS). We aimed to assess the efficacy and safety of RTX use in these patients. METHOD: A retrospective study of all patients with idiopathic NS treated with RTX was conducted in a pediatric nephrology division of a tertiary hospital. Demographic, anthropometric, clinical and analytical data were collected prior to treatment and at 6, 12, and 24 months. RESULTS: Sixteen patients were included (11 males), with a median (25(th)–75(th) percentile, P25–P75) age at diagnosis of 2 (2.0–2.8) years. Fifteen were steroid-sensitive and 1 was steroid-resistant and sensitive to cyclosporine. The median age at administration of RTX was 10 (6.3–14.0) years. Throughout a median follow-up time of 2.5 (1.0–3.0) years, 6 (37.5%) patients achieved partial remission and 7 (43.8%) had no relapses and were not taking any immunosuppressants at the 24-month follow-up visit. Regarding complications, 1 patient presented persistent hypogammaglobulinemia. Compared with the 12-month period before RTX, there was a decrease in the median number of relapses at 6 and 12 months [3 (3.0–4.0) vs 0 (0–0.8) and 0.50 (0–1.0), respectively; p = 0.001] and in the daily steroids dose (mg/kg/day) at 6, 12, and 24 months [0.29 (0.15–0.67)vs [0.10 (0.07–0.13); p = 0.001], [0.12 (0.05–0.22); p = 0.005] and [0.07(0.04–0.18); p = 0.021]], respectively. There was also a reduction in the median BMI z score at 24 months [2.11 (0.45–3.70) vs. 2.93 (2.01–3.98); p = 0.049]. CONCLUSION: Our results confirm the efficacy and safety of RTX use in pediatric idiopathic NS and highlight its’ potential cardiometabolic benefits.