Single- and multiple-dose escalation study to assess pharmacokinetics, pharmacodynamics and safety of oral esaxerenone in healthy Japanese subjects

AimsTo characterize the pharmacokinetics, pharmacodynamics and safety of esaxerenone, a mineralocorticoid receptor antagonist, in healthy adult Japanese men. MethodsDouble-blind, placebo-controlled, sequential, dose-escalation studies were conducted in subjects randomized to receive oral once-daily esaxerenone (ranges: 5-200mg [single-dose]; 10-100mg over 10days [multiple-dose]) or placebo under fasting conditions. Plasma concentrations were analysed by liquid chromatograph-tandem mass spectrometry. Pharmacokinetic parameters were determined by noncompartment analysis. Plasma/urine levels of pharmacodynamic biomarkers for mineralocorticoid receptor activity were evaluated. ResultsIn total, 48/48 and 39/40 subjects completed the single- and multiple-dose studies, respectively. Exposures were generally dose-proportional. The t(max), t(1/2) and CL/F remained unchanged, independent of dose; the respective ranges were 1.5-4.0h, 22.3-25.1h, and 4.0-5.2lh(-1) (multiple-dose study). V-z/F ranged from 136.5 to 283.7l in the multiple-dose study, and exposure reached steady state by day 4. The mean observed accumulation ratio, by dose, ranged from 1.36-1.98. The urinary Na+/K+ ratio increased after single-dose administration; however, its relationship to the doses tested remains unclear. Plasma renin activity, active renin concentration and aldosterone concentration increased dose-dependently. Although blood potassium levels increased dose-dependently in the multiple-dose study (reaching a maximum meanstandard deviation of 4.63 +/- 0.354mmoll(-1) in the 100-mg group), no safety/tolerability-related problems were detected in either study. ConclusionsExposure levels in healthy adults receiving esaxerenone were generally dose-proportional. Dose-dependent changes in plasma pharmacodynamic biomarkers for the mineralocorticoid receptor were identified during multiple-dose treatment and support the pharmacological activity of esaxerenone. No important safety concerns were identified.