Long-Term Results of Initial Therapy With Abacavir and Lamivudine Combined With Efavirenz, Amprenavir/Ritonavir, or Stavudine

OBJECTIVE: To compare alternative class-sparing antiretroviral regimens in treatment-naive subjects. DESIGN: Open-label, multicenter, randomized trial of up to 3 consecutive treatment regimens over 96 weeks. METHODS: Two hundred ninety-one subjects received abacavir (ABC) and lamivudine and efavirenz (nonnucleoside reverse transcriptase inhibitors [NNRTIs]), ritonavir-boosted amprenavir (protease inhibitor [PI]), or stavudine (nucleoside reverse transcriptase inhibitor [NRTI]) by random assignment. The primary end points were the percentages of subjects with plasma HIV-1 RNA levels <400 copies/mL and time to treatment failure over 96 weeks. RESULTS: Ninety percent of subjects completed 96 weeks of follow-up, and 79% remained on study treatment. At week 96, there were no differences between arms in the percentages of subjects with plasma HIV-1 RNA levels <400 and <50 copies/mL, mean changes in plasma HIV-1 RNA levels, time to treatment failure, time to first or second virologic failure, or CD4 cell counts. The NNRTI arm had a greater percentages of subjects with RNA levels <or=50 copies/mL at weeks 24 and 48 and a greater overall duration of plasma HIV-1 RNA levels <400 copies/mL. Three subjects in the NNRTI arm had treatment failure on their first regimen and switched therapy compared with 16 in the NRTI arm and 13 in the PI arm. Twenty-one subjects had hypersensitivity reactions attributed to ABC (7.3%). Fewer drugs were used by subjects in the NNRTI arm, and fewer subjects in the NNRTI arm used 3 drug classes. CONCLUSIONS: All treatment regimens demonstrated excellent 96-week results. Secondary analyses favored the NNRTI regimen over the PI and NRTI regimens.