TVR will be taken with food, 30 minutes after the start of a meal. EFV and TDF should be taken on an empty stomach (2.5 hours after start of breakfast). Pharmacokinetic profiles of TVR and VRT-127394 (R-diastereomer of TVR) will be measured up to 8 hours after intake of the morning dose on Day 7 of Treatments A and C, and up to 12 hours after intake of the morning dose on Day 7 of Treatment D. Pharmacokinetic profiles of EFV and tenofovir will be measured up to 24 hours after intake on Day 7 of Treatments B, C, and D. Safety and tolerability evaluations will be recorded at regular intervals throughout the trial period. Treatment A: TVR every 8 hours alone for 6 days with an additional morning intake on Day 7. Treatment B: EFV + TDF once daily alone for 7 days. Treatment C: TVR every 8 hours + EFV once daily + TDF once daily for 7 days. Treatment D: TVR every 12 hours + EFV once daily + TDF once daily for 7 days.