Background: Etravirine (ETR) is recommended as twice-daily dosing in pretreated patients. There are no data regarding the use of ETR once daily in HIV-experienced patients with prior resistance to first-generation non-nucleoside reverse transcripase inhibitors (NNRTIs).
Objectives: To evaluate the capacity of once-daily ETR to maintain suppressed viremia over 48 weeks after switching from ETR twice daily in NNRTI-experienced patients.
Methods: In this pilot open-label study, patients with plasma viral load (pVL) <50 copies/mL on a stable ETR 200 mg bid regimen were enrolled to switch to ETR 400 mg qd and followed up over 48 weeks. The primary endpoint was the proportion of patients with pVL <50 copies/mL at week 24. Secondary endpoints included the rate of pVL< 50 copies/mL at week 48, ETR pharmacokinetic parameters, and tolerability and resistance profile.
Results: Twenty-four patients were included. They had extensive antiretroviral treatment for a median of 14 years (range, 1-19). All except for 2 had prior resistance to NNRTIs. Seven patients discontinued ETR once daily prior to week 48 for virological failure (3), protocol deviation (3), and side effects (1). At week 24, 95% of patients maintained pVL< 50 copies/mL (95% CI, 78.4-99.7) and 85% at week 48 (95%CI, 65.6-95.8). Two of the 3 patients with virological failure had ETR resistance mutations prior to initiation. The median ETR C(trough) level remained stable after switching from twice daily 515 ng/mL (340-758) to once daily 422 ng/mL (264-655).
Conclusion: These results suggest that ETR is effective as a once-daily regimen in patients with prior NNRTI experience when HIV is sensitive to ETR. The stability of C(trough) concentrations on a once-daily regimen confirms the once-daily profile of the drug in experienced patients.