Mycophenolate mofetil versus tacrolimus for maintenance of remission in children with frequently relapsing and steroid-dependent nephrotic syndrome: a pilot randomized controlled trial.

BACKGROUND: Frequently relapsing nephrotic syndrome (FRNS) and steroid-dependent nephrotic syndrome (SDNS) require steroid-sparing agents to maintain remission and reduce steroid-related toxicity. Comparative evidence between mycophenolate mofetil (MMF) and tacrolimus (TAC) remains limited. The objective of this study was to compare the efficacy and safety of MMF and TAC for maintenance of remission in children with FRNS/SDNS. METHODS: This prospective, open-label, pilot randomized controlled trial was conducted at a tertiary care centre in India between October 2023 and March 2025. Children aged 2-18 years with FRNS or SDNS receiving only prior corticosteroids were randomized (1:1) to MMF (1200 mg/m2/day) or TAC (0.1-0.15 mg/kg/day). The primary outcome was relapse-free survival at 6 months. Secondary outcomes included relapse rates over 12 months, steroid exposure, kidney function, blood pressure, growth parameters, and adverse events. RESULTS: Forty patients were enrolled (20 in each group). Relapse-free survival at 6 months was comparable between groups, with no significant difference in time to first relapse. Sustained remission and overall relapse rates over 12 months were also similar. Kidney function was significantly better preserved in the MMF group, whereas TAC was associated with higher serum creatinine and lower eGFR. Blood pressure and body mass index were higher in the TAC group, while growth velocity was greater in the MMF group. Adverse events were mostly mild and comparable. CONCLUSIONS: MMF and TAC showed comparable efficacy in maintaining remission in children with FRNS/SDNS. However, TAC was associated with less favourable kidney, cardiovascular, and growth profiles. MMF may represent a safer alternative for long-term therapy, although larger multicentre trials are needed.