A Randomized, Single‐Center, Double‐Blind, Placebo‐Controlled Multiple‐Dose Phase 1 Study to Evaluate the Safety, Pharmacokinetics, and Pharmacodynamics of Imarikiren in Healthy Adult Nonelderly and Elderly Male Subjects

: Imarikiren hydrochloride (TAK-272/ SCO-272) is a novel direct renin inhibitor. This randomized, double-blind, phase I study evaluated the safety and pharmacokinetics/pharmacodynamics of multiple oral administrations of imarikiren in healthy nonelderly (aged 20-45 years) and elderly (aged 65-85 years) Japanese male subjects. Subjects were randomized within 1 of 3 cohorts to receive imarikiren or placebo: Cohort 1 (imarikiren 80 mg; nonelderly), Cohort 2 (imarikiren 160 mg; nonelderly), or Cohort 3 (imarikiren 80 mg; elderly). Imarikiren or placebo was administered orally, once daily, for 7 days. Accumulation of imarikiren did not occur during the 7-day treatment period. Area under the plasma-concentration time curve and maximum plasma concentration of imarikiren were higher in elderly than in nonelderly subjects (52% and 39% higher, respectively). Inhibition of plasma renin activity was observed for 7 days and was maintained for at least 71 hours after the last imarikiren administration at the 80-mg (nonelderly and elderly) and 160-mg (nonelderly) doses. Plasma active renin concentration increased in nonelderly and elderly subjects; peak concentrations were higher on day 7 than on day 1. Increase from baseline in plasma active renin concentration was smaller in elderly than in nonelderly subjects during the 7-day treatment period and until 71 hours after last imarikiren administration. Treatment-emergent adverse events were reported in 33.3% (elderly) and 22.2% (nonelderly) of imarikiren subjects. Multiple oral administrations of imarikiren for 7 days were safe and well tolerated with no drug accumulation and strong and sustained suppression of plasma renin activity.