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
Conclusions: All treatment regimens demonstrated excellent 96-week results. Secondary analyses favored the NNRTI regimen over the PI and NRTI regimens.