Proteinuria is an established risk factor for
diabetic nephropathy. Recent studies indicate that some
xanthine oxidase inhibitors have a renoprotective effect. The aim of this study was to assess whether
topiroxostat reduces
albuminuria in hyperuricemic patients with
diabetic nephropathy and overt
proteinuria. The ETUDE study is an ongoing 24-week, multicenter, open-label, randomized (1:1), parallel group study involving hyperuricemic patients with
diabetic nephropathy (estimated glomerular filtration rate [eGFR] ≥ 20 mL/min/1.73 m(2)) and overt
proteinuria (0.3 ≤ urine
protein to
creatinine ratio (UPCR) < 3.5 g/g Cr). Patients are randomly assigned to high dose (
topiroxostat 160 mg daily) or low dose (
topiroxostat 40 mg daily) on top of standard of care. The primary endpoint is the change in
albuminuria indicated by urine
albumin-to-
creatinine ratio after 24 treated weeks relative to the baseline values. This trial was registered at the Japanese University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR: UMIN 000015403). The background, rationale, and study design of this trial are presented here. Seventy-six patients from four registered facilities have already been enrolled and received at least one dose of
topiroxostat. This trial will end in 2017. The ETUDE trial is the first randomized controlled study of
topiroxostat in hyperuricemic patients with
diabetic nephropathy and overt
proteinuria. We will clarify the pleiotropic function of
topiroxostat including an anti-albumiuric effect as well as its effects on safely decreasing serum
uric acid levels.