This is a Phase I, open-label (the participant will know the identity of the treatment they receive), 3-period study to investigate the pharmacokinetic (what the body does to the medication) interaction of steady-state (constant concentrations in your blood resulting from a fixed dosing regimen) rilpivirine and steady-state rifabutin. Twenty healthy participants will be enrolled and will receive 3 different treatments (treatment A: rilpivirine 25 mg once daily administered daily for 11 days; treatment B: rilpivirine 50 mg once daily administered for 11 days + rifabutin 300 mg daily administered for 17 days; treatment C: rilpivirine (in a regimen to be determined based on an interim analysis of treatments A and B) administered for 11 days + rifabutin 300 mg daily administered for 17 days). All 20 participants will be randomized (the study drug is assigned by chance) to receive treatments A (10 participants) and treatment B (10 participants) and there will be a washout period of at least 21 days between treatments A and B. After all participants have completed treatments A and B, there will be an interim analysis to decide upon the dosing regimen for rilpivirine in treatment C (the rilpivirine regimen in treatment C could be either once daily or twice daily with a total daily dose of rilpivirine between 25 and 75 mg). All 20 participants will receive treatment C. Safety and tolerability will be evaluated throughout the study.
The purpose of this study is to explore the pharmacokinetics of different dosing regimens of rilpivirine in combination with rifabutin in healthy participants.