Inclusion Criteria

Patients must have:

• Documented HIV infection.
• HIV RNA >= 400 copies/ml within 14 days prior to randomized study drug administration.
• No active AIDS-defining opportunistic infection or disease.
• Signed, informed consent from parent or legal guardian of patients less than 18 years of age.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• Unlikely to complete the randomized dosing period.
• Malabsorption syndrome or other gastrointestinal dysfunction that might interfere with drug absorption or ability to take oral medications.
• Serious medical conditions (e.g., diabetes, cardiac dysfunction, hepatitis) that would compromise patient safety.

Concurrent Medication:

Excluded:

• Cytotoxic chemotherapeutic agents (except local treatment for Kaposi's sarcoma).
• Investigational treatments (treatment through Treatment IND or expanded-access programs are evaluated individually).
• Immunomodulating agents such as systemic, high-dose corticosteroids, interleukins, or interferons.
• Terfenadine, astemizole, cisapride, triazolam, midazolam, and ergotamine/dihydroergotamine-containing regimens.

Concurrent Treatment:

Excluded:

Radiation therapy (except local treatment for Kaposi's sarcoma).

Patients with the following prior conditions are excluded:

Clinically relevant pancreatitis or hepatitis within the last 6 months.

Prior Medication:

Excluded:

• Cytotoxic chemotherapeutic agents within 30 days of study drug administration (except local treatment for Kaposi's sarcoma).
• Protease inhibitor therapy.
• Dose of vaccine through an investigational HIV vaccine trial within the 3 months prior to study drug administration.
• Immunomodulating agents such as systemic, high-dose corticosteroids, interleukins, or interferons within 30 days of study drug administration.

Prior Treatment:

Excluded:

Radiation therapy within 30 days prior to study drug administration (except local treatment for Kaposi's sarcoma).

Risk Behavior:

Excluded:

Current alcohol or illicit drug use that may interfere with drug absorption or ability to take oral medication.

Required:

NRTI therapy at day of entry and up to screening.

Required:

>= 12 weeks of NRTI therapy.