Non-Compartmental Pharmacokinetics and Safety of Single-Dose Eldecalcitol (ED-71) in Healthy Chinese Adult Males.

Background And Objectives: Eldecalcitol (ED-71) is a novel active vitamin D derivative, used for the treatment of osteoporosis. This is the first clinical study to investigate the pharmacokinetics and safety of eldecalcitol in Chinese subjects.

Methods: This was an open, single-center, randomized, two-dose level, two-period crossover phase I study in 24 healthy Chinese adult males. Eligible subjects received a single oral dose of eldecalcitol capsule 0.5 or 0.75 μg at period 1 or period 2, monitored over a 144-h observation period for pharmacokinetics and a 14-day observation period for safety. The wash-out time was 14 days. The data observed in this study were compared with historical data in Japanese subjects to evaluate the inter-ethnic differences in pharmacokinetics.

Results: After single doses of 0.5 and 0.75 μg eldecalcitol, the maximum serum concentration (C) of eldecalcitol was reached within 3.0-4.0 h (C was 0.0638 ± 0.0076 ng/ml in the 0.5-μg group and 0.0944 ± 0.0126 ng/ml in the 0.75-μg group, area under the concentration-time curve from 0 to 24 h (AUC) was 1.02 ± 0.15 ng·h/mL in the 0.5-μg group and 1.57 ± 0.26 ng·h/mL in the 0.75-μg group). The pharmacokinetic parameters was similar between the Chinese and Japanese subjects; both C and partial AUCs could be considered to be dose-proportional over the tested dose range of 0.5-0.75 µg in Chinese subjects, which was in line with previously published results on eldecalcitol linear pharmacokinetics (range 0.1-1.0 µg) in Japanese subjects. Alanine aminotransferase increase was the most common adverse event (AE). No drug-related serious AEs were reported. All of the drug-related AEs of eldecalcitol were mild in severity.

Conclusion: Pharmacokinetic exposure (C and partial AUCs) was dose-proportional over the tested dose range of 0.5-0.75 µg in healthy Chinese adult males. The pharmacokinetic character of eldecalcitol in Chinese subjects was similar to historical data from Japanese subjects. Eldecalcitol was well tolerated at doses ranging from 0.5 to 0.75 µg, with no new safety signals identified.

Clinical Trial Registration: This study was registered at the China Food and Drug Administration (Registration number: 2014L02212 and 2014L02213), and also registered at http://www.chinadrugtrials.org.cn (No. CTR20160430).