To determine the response of hemodialysis (HD) patients to topiroxostat after a switch from febuxostat, we evaluated the efficacy, tolerability, and serum concentration of topiroxostat in HD patients after the switch. In this 16-month prospective observational study, we assessed the serum uric acid (UA) levels, other laboratory data, and serum topiroxostat concentrations of 10 HD patients who had been receiving febuxostat at a dose of 10 mg/d for over 1 year. No statistical difference was observed between the tolerability index at baseline and 16 months after the switch to topiroxostat. Serum UA after the switch in all patients (attained serum UA levels of ≤6 mg/dL) was 5.6±1.7 mg/dL (60%) at baseline, 4.9±0.5 mg/dL (100%) at 6 months and 5.7±0.4 mg/dL (50%) at 16 months (p=0.25), respectively. In patients with baseline serum UA levels >6 mg/dL, serum UA was significantly reduced at 6 and 16 months compared with baseline. Minimum serum concentrations of serum topiroxostat were lower than the limit of quantification (<25 ng/mL). Our results indicate that a switch from febuxostat 10 mg/d to topiroxostat 40 mg/d might reduce serum UA levels, with no change in other clinical laboratory data over the long term. These effects were more frequent in patients with high serum UA levels. Furthermore, topiroxostat therapy was more cost effective than febuxostat therapy. Thus, topiroxostat therapy could be a better treatment option for HD patients who develop high serum UA levels after febuxostat 10 mg/d administration.
Keywords: febuxostat; hemodialysis; serum concentration; serum uric acid level; topiroxostat.