Mycophenolate mofetil non-inferior to prednisone for first-episode nephrotic syndrome in children

BACKGROUND: Prolonged glucocorticoid therapy is the standard initial treatment for idiopathic nephrotic syndrome in children, but is associated with marked toxic effects. We aimed to assess whether a novel treatment protocol with mycophenolate mofetil is as effective as standard therapy with prednisone, while reducing the burden of glucocorticoid-related side-effects. METHODS: INTENT was a multicentre, open-label, randomised, controlled, parallel-group, non-inferiority, phase 3 trial done in 37 community, municipal, and university hospitals in Germany. Patients aged 1-10 years with a first episode of steroid-sensitive nephrotic syndrome were randomly assigned (1:1) by a centralised web-based tool to receive either mycophenolate mofetil or prednisone (standard treatment), after remission induced by prednisone or prednisolone at a dose of 60 mg/m body surface area (maximum 80 mg/day) within 28 days. Block randomisation (block size of eight) was stratified by age (<7 years or ≥7 years). Mycophenolate mofetil was given at 1200 mg/m body surface area per day, twice daily, as a suspension (200 mg/mL) for a total treatment duration of 12 weeks. Prednisone was administered once, twice, or three times daily for 6 weeks at 60 mg/m body surface area per day (maximum 80 mg). Thereafter, prednisone was given for a further 6 weeks at 40 mg/m body surface area (maximum 60 mg) once daily in the morning on alternate days. The primary endpoint was the occurrence of a treated relapse during the 24-months of follow-up in the modified intention-to-treat population. The non-inferiority margin was 15%. This trial is registered with the European Union Drug Regulating Authorities Clinical Trials database (EudraCT 2014-001991-76) and has been completed. FINDINGS: Between Oct 12, 2015, and April 23, 2021, 497 patients were screened for eligibility, 272 of whom were randomly assigned (136 to each group). The modified intention-to-treat population comprised 269 patients, of whom 173 (64%) were boys and 96 (36%) were girls (median age 4·0 years [IQR 2·0-5·0]). Mycophenolate mofetil was non-inferior to prednisone for the primary endpoint of treated relapse (106 [79·1%] of 134 vs 101 [74·8%] of 135; difference 4·3% [90% CIs -4·2 to 12·7]; p=0·019). At the end of the first 12 weeks of treatment, fewer glucocorticoid-related side-effects were observed in the mycophenolate mofetil group than the prednisone group, including arterial hypertension (78 [59·1%] of 132 vs 115 [87·1%] of 132; difference -28·0% [95% CI -37·7 to -17·5]), lower BMI (BMI Z score 0·16 [SD 0·85] vs 1·41 [1·02]; difference -1·24 [-1·47 to -1·02]), and fewer psychological abnormalities (37 [27·8%] of 133 vs 77 [57·9%] of 133; difference -30·1% [-40·9 to -18·4]). More patients in the mycophenolate mofetil group than in the prednisone group developed infections (93 [69·9%] of 133 vs 74 [55·6%] of 133; difference 14·3% [2·7 to 25·5]) and there was no statistically significant difference in the number of patients who developed at least one gastrointestinal disorder (22 [16·5%] of 133 vs 13 [9·8%] of 133; difference 6·8% [-1·5 to 14·8]). INTERPRETATION: Our findings suggest that mycophenolate mofetil is non-inferior to standard prednisone treatment, with reduced glucocorticoid-related toxic effects. These findings could modify the initial standard of care for patients with steroid-sensitive nephrotic syndrome. FUNDING: German Federal Ministry of Education and Research.