Safety, tolerability, and pharmacokinetics of TAS-108 in normal healthy post-menopausal female subjects: a phase I study on single oral dose

Abstract

The present study was conducted to evaluate the safety, tolerability, and pharmacokinetics of TAS-108 after ascending single oral doses and to analyse preliminarily the effect of food on the pharmacokinetics of TAS-108 in normal healthy post-menopausal female subjects. Twelve healthy subjects participated in an open-label, ascending single-dose, alternating group, safety, tolerance, and pharmacokinetic study of TAS-108 administered orally to two groups of the subjects, one given alternating doses of 10, 40, 120 mg (group A) and the other of 20, 80, 160 mg (group B), in the fasting state. In addition, six subjects (group A) were administered an additional dose at 120 mg TAS-108 after food consumption. Plasma and urine samples for measurement of TAS-108 were analysed by validated analytical procedures using a liquid chromatographic method with tandem mass spectrometric detection (LC/MS/MS). There was no dose-dependent increase in any adverse events (AEs), and there were no serious AEs or deaths. TAS-108 was readily absorbed following oral administration of the 80-, 120- and 160-mg doses. Plasma TAS-108 levels steadily declined, generally in a mono-exponential manner, with overall mean t(1/2) values ranging from 3.04 to 4.43 h in the fasting groups. Administration of TAS-108 after a high-fat meal markedly increased the bioavailability of the drug. The mean C(max) and AUC(0--t) values increased after a high-fat breakfast by 182 and 191% compared with the fasting value respectively. In this escalating dose study of TAS-108, the drug was well tolerated by the participants. The maximum and systemic exposure to TAS-108 tended to increase with increasing dose and its bioavailability markedly increased after high-fat food intake.