This is a randomized, double-blind, double-dummy, 48-week, comparative study. Approximately 150 HIV-infected, treatment-naïve patients with CCR5-tropic virus will be stratified by HIV-1 RNA: ≥100,000 copies/mL versus <100,000 copies/mL and will be randomized 2:2:1 to receive:

• Arm A: CVC 100 mg (2 tablets, 50 mg each) QD + CVC matching placebo (2 tablets) QD + EFV matching placebo (1 tablet) QHS + FTC/TDF (1 tablet) QD.
• Arm B: CVC 200 mg (4 tablets, 50 mg each) QD + EFV matching placebo (1 tablet) QHS + FTC/TDF (1 tablet) QD.
• Arm C: CVC matching placebo (4 tablets) QD + EFV 600 mg (1 tablet) QHS + FTC/TDF (1 tablet) QD.

Doses of both CVC/placebo and EFV/ placebo will be administered as double-blinded study drug. FTC/TDF will be administered as open-label study drug in a fixed-dose combination formulation (Truvada). CVC/placebo should be taken following breakfast; EFV should be taken on an empty stomach at bedtime.

HIV-1 RNA levels and CD4+ and CD8+ cell counts, percentages, and ratios will be measured at every visit. Samples for viral tropism and resistance testing in case of virologic failure will be collected at Screening and each on-treatment visit.

Biomarkers associated with inflammation and immune activation will be measured at Baseline (predose) and each study visit thereafter, with flow cytometry obtained at weeks 4, 12, 24, 48, and 52.

Fasting metabolic indicators of glucose control (glucose and insulin for HOMA-IR, HbA1c) and fasting lipid profiles (HDL, LDL, total cholesterol, and triglycerides) will be measured at Baseline (predose) and Weeks 4, 12, 24, 48, and 52. Waist-to-hip ratios will be measured at Baseline and Weeks 24 and 48.

Plasma samples will be collected and stored for possible future studies at Baseline (predose) and every visit thereafter.