The purpose of this study is to compare the safety of didanosine plus stavudine plus nelfinavir (NLF) with that of zidovudine plus lamivudine plus NLF. This study also examines how long these drug combinations are effective in lowering viral load (level of HIV in the blood).

Inclusion Criteria

Patients must have:

Within 15 business days prior to randomization:

• CD4 cell count greater than or equal to 100 cells/mm3.
• HIV RNA greater than or equal to 2,000 copies/ml by Roche Amplicor Assay.

Exclusion Criteria

Co-existing Condition:

Patients with any of the following symptoms or conditions are excluded:

• Bilateral peripheral neuropathy.
• Intractable diarrhea.
• Proven or suspected acute hepatitis within 30 days prior to study entry.

Concurrent Medication:

Excluded:

- Therapy for any co-existing disease that may interfere with patient ability to participate in this study.

Concurrent Treatment:

Excluded:

Therapy for any co-existing disease that may interfere with patient ability to participate in this study.

Patients with the following prior conditions are excluded:

History of acute or chronic pancreatitis.

Prior Medication:

Excluded:

• Therapy for any previous disease that may interfere with patient ability to participate in this study.
• Excluded within 14 days prior to randomization:

Greater than 4 weeks of nucleoside therapy or greater than 1 week of protease inhibitor therapy.

• Excluded within 3 months of the start of this study or expected need at time of enrollment:
• Agents with significant systemic myelosuppressive, neurotoxic, pancreatoxic, hepatotoxic, or cytotoxic potential.
• Inability to tolerate oral medication.

Prior Treatment:

Excluded:

Therapy for any previous disease that may interfere with patient ability to participate in this study.

Risk Behavior:

Excluded:

Active alcohol or substance abuse that, in the opinion of the investigator, is sufficient to prevent adequate compliance with study therapy or to increase the risk of developing pancreatitis.