TMC114-TiDP3-C181: Study to Assess the Pharmacokinetics of Darunavir (DRV) With Different Doses of Ritonavir in Healthy Volunteers.

Primary Outcome Measures:

• To determine the effect of different ritonavir doses (20, 50, 100 mg ritonavir) in DRV oral exposure following once-daily oral dosing of DRV/rtv for 7 days, in order to establish an optimal ritonavir boosting dose for DRV
  

Secondary Outcome Measures:

• To evaluate short-term safety and tolerability of DRV following administration of DRV 800 mg once-daily in the presence of different doses of ritonavir for 7 days in healthy volunteers
  

This is a Phase I, open-label, randomized (study drug assigned by chance), 3-way crossover trial in healthy volunteers to assess the pharmacokinetics of darunavir (DRV), co-administered with different doses of ritonavir. The trial population will consist of 18 healthy adult volunteers. During 3 subsequent sessions, each volunteer will receive in a randomized way: Treatments A, B and C. In Treatment A, 800 mg DRV once-daily and 100 mg ritonavir once-daily will be administered. In Treatment B, 800 mg DRV once-daily and 50 mg ritonavir once-daily will be administered. In Treatment C, 800 mg DRV once-daily and 20 mg ritonavir once-daily will be administered. All treatments will be administered for 7 days and intake of DRV and ritonavir will be under fed conditions. DRV will be formulated as a 400 mg tablet; ritonavir will be formulated as an oral solution containing 80mg/mL ritonavir. In each treatment session, full pharmacokinetic profiles of DRV and ritonavir will be determined up to 24 hours after administration on Day 1 and up to 72 hours after administration on Day 7. There will be a washout period of at least 7 days between subsequent treatments. Safety and tolerability will be evaluated continuously throughout the trial. During 3 subsequent sessions, each volunteer will receive in a randomized way Treatments A, B and C. In Treatment A, 800/100 mg DRV/rtv once-daily will be administered. In Treatment B, 800/50 mg DRV/rtv once-daily will be administered. In Treatment C, 800/20 mg DRV/rtv once-daily will be administered. All treatments will be administered for 7 days. DRV will be formulated as a 400 mg tablet; ritonavir will be formulated as an oral solution containing 80mg/mL ritonavir.