Inclusion Criteria

Concurrent Medication:

Allowed:

Based on medical history, medical condition, prior use of antiretroviral drugs, and genotypic analysis of the predominant strain of HIV-1 isolated from plasma, administration of at least 2 available antiviral agents by prescription may be given with MKC-422.

Patients must have:

- HIV infection with HIV-1 RNA greater than or equal to 2,000 by Roche Amplicor method, within 30 days of entry.

Prior Medication:

Allowed:

• Prior nucleoside reverse transcriptase and protease inhibitors.
• Cytotoxic chemotherapy more than 30 days prior to entry.

Exclusion Criteria

Co-existing Condition:

Patients with the following symptoms or conditions are excluded:

• Malabsorption or severe chronic diarrhea within 30 days prior to entry, or inability to consume adequate oral intake because of chronic nausea, emesis, or abdominal or esophageal discomfort.
• Inadequately controlled seizure disorder.
• Acute and clinically significant medical event within 30 days of screening.
• Any clinical or laboratory abnormality greater than Grade 3 toxicity, with the exception of the listed laboratory values.

Prior Medication:

Excluded:

• Non-nucleoside reverse transcriptase inhibitor therapy.
• Any unapproved experimental antiretroviral therapy.

Prior Treatment:

Excluded:

• Radiation therapy within 30 days of entry, except to a local lesion.
• Transfusion of blood or blood products within 21 days of screening.

Risk Behavior:

Excluded:

Active substance abuse that may interfere with compliance or protocol evaluations.