ABSTRACT: OBJECTIVE:Fabry disease is a rare X-linked disease caused by mutations to the GLA gene, resulting in a deficiency of the lysosomal enzyme alpha-galactosidase A. This study evaluated the pharmacokinetics, safety, and tolerability of ascending single doses of oral migalastat hydrochloride (HCl), an investigational drug, in healthy Japanese volunteers. METHODS:In this phase I, randomized, placebo-controlled, single-blind, ascending single-dose, cross-over study, migalastat HCl (50?mg, 150?mg, or 450?mg) or placebo was administered orally to 14 fasting male Japanese volunteers (aged 20-55 years) on 4 non-consecutive days. Main plasma and urine pharmacokinetic end-points included maximum observed plasma concentration (C max), time to C max (t max), area under the plasma concentration-time curve (AUC), apparent terminal-phase half-life (t 1/2), urinary recovery of unchanged drug, renal clearance, and percentage of drug excreted in urine. Safety end-points included adverse events, clinical signs and symptoms (e.g., hematology, chemistry, and urinalysis), vital signs (blood pressure and heart rate), and 12-lead electrocardiogram. CLINICAL TRIAL REGISTRATION NUMBER:ClinicalTrials.gov registration identifier is NCT01853852. RESULTS:Median t max of migalastat was 3.0-3.5?h. Migalastat HCl concentrations declined relatively rapidly, with a mean t 1/2 of 3.2-4.0?h. The amount of migalastat HCl recovered in the urine and the percentage of migalastat HCl excreted unchanged over 24?h were consistent (?45-50%) across the dose range. The AUC and C max of migalastat HCl were dose proportional from 50-450?mg. Safety results were similar to those observed in non-Japanese populations. CONCLUSIONS:This study demonstrated that ascending single doses of migalastat HCl (50?mg, 150?mg, 450?mg) are absorbed at a moderate rate and eliminated relatively rapidly, with a safety profile consistent with that observed in non-Japanese populations. These results confirm the dose-proportional pharmacokinetics of migalastat HCl from 50-450?mg. This study was limited by a small subject population and a short-term follow-up.