Objectives: Complex antiretroviral regimens can be associated with increased toxicity and poor adherence. Our aim was to compare the efficacy and safety of switching to two simplified, class-sparing antiretroviral regimens.
Methods: We conducted a randomized, open-label study in 236 patients with virologic suppression who were taking a three- or four-drug protease inhibitor or non-nucleoside reverse transcriptase inhibitor regimen for ≥ 18 months. Patients received lopinavir/ritonavir (LPV/r) 533 mg/133 mg twice daily + efavirenz (EFV) 600 mg once daily or EFV + two nucleoside reverse transcriptase inhibitors (NRTI). Primary study endpoint was time to first virologic failure (VF, confirmed HIV-1 RNA > 200 copies/ml) or discontinuation because of study drug-related toxicity.
Results: After 2.1 years of follow up, patients receiving LPV/r + EFV discontinued treatment at a greater rate than patients receiving EFV + NRTI (P < 0.001). Twenty one patients developed VF (14 receiving LPV/r + EFV and seven receiving EFV + NRTI) and 26 discontinued because of a study drug-related toxicity (20 receiving LPV/r + EFV and six receiving EFV + NRTI). Time to VF or study drug related-toxicity discontinuation was significantly shorter for LPV/r + EFV than EFV + NRTIs (P = 0.0015). A significantly higher risk of drug-related toxicity occurred with LPV/r + EFV, mainly for increased triglycerides (P = 0021). A trend toward a higher VF rate occurred with LPV/r + EFV in an intent-to-treat and as-treated analyses (P = 0.088 and P = 0.063 respectively).
Conclusions: Switching to EFV + NRTI resulted in better outcomes, fewer drug-related toxicity discontinuations and a trend to fewer virologic failures compared to switching to LPV/r + EFV.