Comparison of atazanavir with lopinavir/ritonavir in patients with prior protease inhibitor failure: a randomized multinational trial

Abstract

Objectives: To compare change from baseline in HIV RNA and fasting low-density lipoprotein (LDL) cholesterol levels in protease inhibitor (PI)–experienced patients receiving unboosted atazanavir 400 mg once daily versus lopinavir 400 mg boosted with ritonavir 100 mg twice daily, with two nucleoside reverse transcriptase inhibitors (NRTIs). Secondary objectives included virologic response, CD4 cell count changes, other lipid changes, safety, and tolerability. Methods: Randomized, open-label, multinational, 48-week study in patients with one PI-regimen failure, HIV RNA ≥ 1000 copies/mL, and CD4 count ≥ 50 cells/mm³. Results: Three hundred patients were randomized; 290 treated (144 atazanavir, 146 lopinavir/ritonavir). Lopinavir/ritonavir resulted in a significantly greater reduction in HIV RNA than unboosted atazanavir (–2.02 vs –1.59 log₁₀ copies/mL, p < 0.001) at week 48. Secondary efficacy endpoints also favored lopinavir/ritonavir; the differences in efficacy between regimens were also observed in secondary analyses comparing those subjects who were susceptible and those subjects who were resistant to their respective PIs at baseline. However, both regimens were equally effective in subjects who had no baseline NRTI mutations. From baseline to week 48, atazanavir resulted in either no change or decreases in fasting LDL cholesterol, total cholesterol, and fasting triglycerides (–6%, –2%, and +1%), whereas lopinavir/ritonavir resulted in increases (+3%, +12%, and +53%) ( p < 0.05, all between-treatment comparisons). Fewer patients were administered lipid-lowering therapy in the atazanavir arm (6% vs 20% for lopinavir/ritonavir). Both regimens were safe and well tolerated. Conclusions: While both treatments demonstrated good antiviral efficacy, relatively greater antiviral suppression was observed with lopinavir/ritonavir. In those patients with no NRTI mutations at baseline, both regimens demonstrated comparable virologic suppression. Atazanavir-treated patients demonstrated a superior lipid profile and required less frequent lipid-lowering treatment.