ARM A1: IDV plus ZDV (or d4T) plus 3TC plus ABC. ARM A2: IDV plus ZDV (or d4T) plus 3TC plus ABC placebo. Patients who achieve a plasma HIV-1 RNA level of 500 copies/ml or more on 2 consecutive determinations may continue their assigned arm in a blinded fashion, or seek the best alternative therapy selected by the local investigator or primary care physician.