The purpose of this study is to look at the effectiveness of giving a new anti-HIV drug (AG1549) plus Viracept (nelfinavir) plus Combivir (a tablet containing zidovudine plus lamivudine) to HIV-infected patients who are not taking anti-HIV drugs.

[Note: As of 2/28/2001, due to toxicity studies and concerns for safety, sites were notified that they need to discontinue patients from the capravirine/placebo arms and continue patients with their background therapies or switch patients to new therapies, as deemed appropriate by the investigators.] Patients are randomized to receive Viracept plus Combivir plus either AG1549 or placebo. Patients remain on their assigned therapy for 48 weeks with one post-therapy follow-up visit. Blood samples are taken regularly to quantify plasma HIV-1 RNA, CD4 and CD8 counts, and peripheral blood mononuclear cells (PBMC). Physical exams, safety assessments, and other tests are also done throughout the study. A blood sample is taken at baseline (pre-dose) for a pharmacokinetics assessment. On Day 8 and at the end of Weeks 4, 8, 16, 24, 36, and 48, pharmacokinetic sampling is done prior to dosing and between 2 to 4 hours post-dose.

• Drug: Lamivudine/Zidovudine
• Drug: Capravirine
• Drug: Nelfinavir mesylate

Inclusion Criteria

Patients may be eligible if they:

• Are HIV-positive.
• Are at least 18 years old.
• Have a CD4 cell count of more than 50 cells/mm3.
• Have an HIV level of more than 5000 copies/ml.

Exclusion Criteria

Patients will not be eligible if they:

• Have ever taken any of the following anti-HIV drugs: nonnucleoside reverse transcriptase inhibitors (NNRTIs), AG1549, Viracept, zidovudine, lamivudine, or Combivir. Other anti-HIV drugs are allowed only if taken for no more than 30 days with the last dose taken more than 6 months prior to study entry.
• Have taken an experimental drug within 28 days of study entry.