Phase I, Open-label, 3-way Crossover Trial in Healthy Volunteers to Determine the Drug-drug Interaction Between TMC435350 and Rifampin After Multiple Dosing.

This is a Phase I, open-label, randomized, 3-way crossover trial in 18 healthy volunteers to investigate the potential drug-drug interaction between rifampin and TMC435350. TMC435350 is a protease inhibitor in development for treatment of chronic HCV infection. The goal is to assess the PK and safety data generated during 3 in-patients sessions. At each session the volunteer will receive one of 3 treatments. Rifampin is a medication commonly given to patients with Mycobacterium infections such as tuberculosis. Some patients have both chronic HCV and tuberculosis, therefore it is necessary to know how the medications will affect each other when they are taken together. Treatment A: TMC435350 200 mg q.d. for 7 days. Treatment B: rifampin 600 mg q.d. for 7 days. Treatment C: the combination of TMC435350 200 mg q.d. + rifampin 600 mg q.d. for 7 days. There will be a washout period of at least 10 days between subsequent sessions. Day 8 of a treatment session is the first day of the washout period. Full pharmacokinetic profiles of TMC435350 will be determined on Day 7 of Treatments A and C. Full pharmacokinetic profiles of rifampin and its active metabolite 25-deacetyl rifampin will be determined on Day 7 of Treatments B and C. Safety and tolerability will be monitored continuously throughout the trial. Volunteers will receive the dose regimens in Treatments A, B, C: Treatment A: TMC435350 200 mg q.d. for 7 days. Treatment B: rifampin 600 mg q.d. for 7 days, Treatment C: the combination of TMC435350 200 mg+rifampin 600 mg both q.d. for 7 days. The volunteers will enter the testing facility the night before the first dosing in each session (on Day -1 = one day before the first dosing) and stay in the testing facility until 72 hours after the last intake of medication on Day (10).