Efficacy, safety, and pharmacokinetics of once-daily boosted darunavir in pretreated HIV-infected patients

Objective and methods: The efficacy and safety of switching to a combined regimen containing darunavir/ritonavir (DRV/r) was investigated in a retrospective study. Results: Sixty-six experienced patients receiving once-daily DRV/r (900/100 mg) in various regimens were included (median age 51 y; male 82%; Centers for Disease Control and Prevention (CDC) stages B or C 70%). The number of patients with plasma HIV RNA < 50 copies/ml increased from 71% (45/63) at baseline (before switch) to 84% (52/62) at visit 1 (weeks 3-11), and to 92% (60/65) at visit 2 (weeks 12-24). CD4 cells increased from 498 +/- 201 cells/mm(3) at baseline to 567 +/- 232 cells/mm(3) by visit 2. Good digestive and metabolic tolerance was observed. The median steady-state DRV plasma concentration, measured 24 +/- 4 h after the last drug intake, was 1427 ng/ml. All DRV plasma concentrations were above the protein-binding corrected median effective concentration (EC50) for the wild-type virus (55 ng/ml). Conclusions: Once-daily DRV/r (900/100 mg) was efficacious in pretreated patients, with safe responses.