A Single- and Multiple-Dose Study To Characterize the Pharmacokinetics, Safety, and Tolerability of Imipenem and Relebactam in Healthy Chinese Participants.

Relebactam/imipenem/cilastatin is approved in the United States to treat complicated urinary tract and intra-abdominal infections in patients who have limited or no alternative treatment options and hospital-acquired bacterial pneumonia (HABP)/ventilator-associated bacterial pneumonia (VABP). Initial pharmacokinetic, safety, and tolerability studies of relebactam with and without imipenem/cilastatin included mostly Caucasian participants. This study evaluated the pharmacokinetics, safety, and tolerability of relebactam/imipenem/cilastatin in 12 healthy Chinese participants after three single doses of increasing concentrations (relebactam at 125, 250, or 500 mg; cilastatin at 250, 500, or 1,000 mg; and imipenem at 250, 500, or 1,000 mg) and after multiple doses every 6 h of a single concentration (relebactam at 250 mg, cilastatin at 500 mg, and imipenem at 500 mg) for 14 days. After single doses, the area under the concentration-time curve (AUC) extrapolated to infinity (relebactam, 15.0 to 70.7 h · mg/liter; imipenem, 24.1 to 109.8 h · mg/liter; cilastatin, 18.4 to 95.3 h · mg/liter) and the AUC from 0 to 6 h (relebactam, 14.2 to 66.3 h · mg/liter; imipenem, 23.4 to 107.3 h · mg/liter; cilastatin, 18.3 to 94.4 h · mg/liter) increased in a dose-dependent manner; clearance (relebactam, 6.9 to 8.3 liters/h; imipenem, 8.6 to 10.4 liters/h; cilastatin, 10.5 to 13.6 liters/h) and half-life (relebactam, 1.4 to 1.6 h; imipenem, 1.0 to 1.2 h; cilastatin, 0.7 to 1.0 h) were consistent between doses. Pharmacokinetic parameters after multiple doses were similar to parameters after a single dose (geometric mean ratios of 0.8 to 1.0 for all three agents). Relebactam/imipenem/cilastatin was well tolerated; mild adverse events occurred during single dosing, and one participant experienced serious adverse events after multiple doses. Pharmacokinetics and safety data are comparable with data from participants of other ethnicities, supporting the use of relebactam/imipenem/cilastatin at the approved dose and schedule in Chinese patients.