Follow-up Outcomes of 100 Children with Frequently Relapsing and Steroid Dependent Nephrotic Syndrome Treated with Oral Cyclophosphamide: A Retrospective Cohort Study.

Abstract

Objectives: The primary objective was to estimate the proportion of children with frequently relapsing nephrotic syndrome (FRNS) and steroid-dependent nephrotic syndrome (SDNS) responding to oral cyclophosphamide, while secondary objectives were to document adverse effects, evaluate relapse-free survival following therapy, and assess outcomes at the last follow-up.

Methods: In this retrospective cohort study, 100 children aged 1-18 years with FRNS or SDNS who received oral cyclophosphamide (cumulative dose ≤168 mg/kg) between 2010 and 2023 at a pediatric nephrology clinic were included. Demographic characteristics, previous treatments, adverse effects, and relapse patterns were retrieved from medical records. Response was defined as being relapse-free and off steroids for ≥6 months after completion of cyclophosphamide therapy, while sustained remission was defined as absence of relapse for ≥2 years.

Results: The median (q1, q3) age at onset of nephrotic syndrome was 4 (2.5, 6) years, and oral cyclophosphamide was initiated at 8 (7, 10) years. The response rate to oral cyclophosphamide was 67%, with a median (q1, q3) relapse-free interval of 9.1 (3.9, 24.7) months. Adverse effects occurred in 28%, most commonly nail discoloration (28 cases), followed by transient leukopenia (4 cases). During follow-up, 56% required an alternative steroid-sparing agent. At a median (q1, q3) follow-up of 72.5 (25.5, 107.25) months, 28% achieved sustained remission, while 69% had infrequent relapses.

Conclusion: Oral cyclophosphamide is effective in children with FRNS and SDNS, inducing sustained remission in a significant proportion and suggesting a prolonged therapeutic effect. However, many children require additional immunosuppressive therapy during follow-up.