Effectiveness of IV cyclophosphamide and mycophenolate mofetil in the treatment of childhood-onset lupus nephritis in a resource-limited setting

Lupus nephritis (LN) is a major cause of morbidity in childhood-onset systemic lupus erythematosus (cSLE). Cyclophosphamide (CYC) and mycophenolate mofetil (MMF) are recommended first-line induction therapies, yet comparative pediatric real-world data, particularly from Asian populations, remain limited. This study compared the effectiveness of CYC and MMF for induction of renal remission and evaluated patterns and predictors of treatment switching among Filipino children with LN. We performed a retrospective cohort study of children with LN treated at a tertiary hospital. Patients received CYC using the NIH intravenous protocol or standard-dose MMF. Complete renal response (CRR) was defined as proteinuria < 0.5 g/day (UPCR < 500 mg/g) with stable renal function. Incidence rates were calculated using person-time methods. Time-to-CRR was analyzed using Kaplan–Meier curves with log-rank testing. Logistic regression identified predictors of treatment switching. A total of 231 patients were included. Baseline disease severity was greater in the CYC group, with higher proteinuria and more frequent Class IV nephritis. Overall CRR incidence was 4.86 per 100 person-months (95% CI 4.18–5.62), with similar rates between CYC and MMF (4.91 vs. 4.71; p = 0.818). CRR occurred in 77.0% and 84.2% of patients, respectively, and median time-to-CRR did not differ significantly (13 vs. 24 months; p = 0.431). Treatment switching was common, mainly due to inadequate response, and occurred more frequently with MMF. Rituximab was used in refractory cases. Female sex and tuberculosis increased the likelihood of switching, whereas higher prednisone dose and rituximab use were protective. No patients progressed to end-stage kidney disease. CYC and MMF showed comparable effectiveness for induction of childhood-onset LN. Frequent treatment modification reflects individualized, real-world management. Prospective multicenter studies are warranted to optimize pediatric treatment strategies. N/A.