Pharmacokinetic and Safety Profile of Ivabradine in Healthy Chinese Men: A Phase I,Randomized, Open-Label,Increasing Single- and Multiple-Dose Study

Background

Ivabradine is a pure heart rate–lowering agent that acts by inhibiting I(f), an important ionic current involved in pacemaker activity in the cells of the sinoatrial node. In the 2012 European Society of Cardiology Guidelines on Heart Failure, it was recommended that patients with a persistently high heart rate, despite treatment with an evidence-based dose of a β-blocker, should be considered for treatment with ivabradine.

Objective

The aim of this study was to explore the pharmacokinetic/pharmacodynamic properties and safety profile of ivabradine in healthy Chinese men.

Methods

This Phase I, randomized, open-label, parallel-arm, single- and multiple-dose study was conducted at the Clinical Pharmacology Center of the Cardiovascular Institute and Fu Wai Hospital at the Chinese Academy of Medical Sciences & Peking Union Medical College in Beijing, People’s Republic of China. Healthy, nonsmoking volunteers were randomly assigned to 1 of 3 treatment groups based on treatment with 5, 10 or 20 mg of ivabradine. After a single dose, the subjects assigned to the 3 dose groups received repeated oral doses of ivabradine BID for 6 days. The plasma concentrations of ivabradine were determined by using a HPLC-MS/MS method. Systolic and diastolic blood pressure and heart rate measurements were taken, and ECG and Holter monitoring was performed. Tolerability was assessed throughout the study by physical and ophthalmologic examinations, vital signs measurement, laboratory analyses, and monitoring of adverse effects.

Results

A total of 36 healthy Chinese men were enrolled in the study. After the single dose, plasma ivabradine C_max and AUC increased approximately linearly with dosage, no statistically significant differences were found in t_½ or T_max between the dose groups. After multiple doses, there was no significant change in T_max compared with the results after a single dose. After repeated doses, t_½, C_max, and AUC increased significantly (P < 0.001). After a single dose, a significant reduction in heart rate at 2 hours’ postdose was observed in the highest dose group, whereas after repeated doses, a significant reduction in heart rate was observed from 2 to 4 hours’ postdose for all 3 groups. The mean (SD) heart rate after repeated doses decreased 12.5 (4.8), 12.4 (6.9), and 20.5 (5.8) beats/min for the 5-, 10-, and 20-mg dose groups, respectively. No clear trend in the changes in QTc, systolic and diastolic blood pressures, or respiration rate was observed. Ivabradine was well tolerated in these healthy Chinese men.

Conclusions

The results of the study in a small population of healthy Chinese men suggest that the PK properties of ivabradine are linear with respect to dosing. After single and repeated oral administration of ivabradine, a significant decrease in heart rate was observed. Ivabradine appeared well tolerated in the population studied. Trial identifier: ACTRN1261300027741.