Patients are randomized to receive stavudine plus lamivudine plus nelfinavir, Combivir (zidovudine plus lamivudine) plus nelfinavir, or Combivir plus abacavir. Patients are stratified into 2 groups based on their screening plasma HIV-1 RNA: (1) greater than 1,000 up to 100,000 copies/ml or (2) greater than 100,000 up to 200,000 copies/ml. Measurements and evaluations for assessment of body fat composition, virologic and immunologic outcomes, markers of alterations in carbohydrate and lipid metabolism, and safety are performed at Baseline, Weeks 4, 8, 16, 24, and every 12 weeks thereafter until Week 96 or withdrawal. In addition, health-related quality of life and health care resource utilization data are collected at specified treatment visits.

Inclusion Criteria

Patients may be eligible for this study if they:

• Are at least 18 years old.
• Are HIV-positive.
• Have a CD4 count greater than 50 cells/mm3.
• Have a viral load greater than 1,000 copies/ml but less than 200,000 copies/ml.
• Have never received anti-HIV medications before. (However, less than 1 week of therapy with lamivudine or a protease inhibitor and less than 4 weeks of therapy with other nucleoside reverse transcriptase inhibitors [NRTIs] is allowed. No therapy with nonnucleoside reverse transcriptase inhibitors [NNRTIs] is allowed.)
• Cannot bear children or agree to use effective methods of birth control during the study. Hormonal methods of birth control (such as birth control pills) are not considered effective for this study.

Exclusion Criteria

Patients will not be eligible for this study if they:

• Have an active AIDS-defining opportunistic infection or disease that, in the doctor's opinion, would make them unable to participate.
• Are unable, in the opinion of the doctor, to follow the dosing schedule and follow-up visit schedule.
• Have a substance abuse problem that would interfere with taking the medications correctly or attending the clinic visits.
• Are enrolled in another study.
• Cannot take medications by mouth or absorb drugs.
• Have hepatitis.
• Have a serious medical condition such as diabetes, congestive heart failure, or other heart disease.
• Need chemotherapy or radiation therapy (except for local treatment of Kaposi's sarcoma).
• Are taking certain medications.
• Are pregnant or breast-feeding.