Inclusion Criteria

Patients may be eligible for this study if they:

• Are HIV-positive.
• Have HIV levels of 50,000 copies/ml or more within 21 days prior to starting treatment.
• Are at least 18 years of age.
• Are willing to use an effective method of birth control during the study.
• (This study has been changed. A CD4 cell count of 50/mm3 or more within 21 days prior to starting treatment is no longer required.)

Exclusion Criteria

Patients will not be eligible for this study if they:

• Are pregnant.
• Have AIDS.
• Cannot take medications by mouth.
• Have hepatitis and it is active.
• Are enrolled in other investigational drug studies.
• Are allergic to any of the study drugs.
• Have a serious medical condition, such as heart disease.
• Have ever taken certain anti-HIV drugs such as nonnucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs).
• Have ever had more than 7 days of treatment with a nucleoside reverse transcriptase inhibitor (NRTI). Patients should have no prior treatment with abacavir and no prior treatment with at least one of the following: lamivudine or zidovudine.
• Have had radiation therapy or chemotherapy within 4 weeks prior to study entry, or plan to have such therapy during the study.
• Have received medications that might affect the immune system, such as systemic corticosteroids, interleukins, vaccines, or interferons within 4 weeks prior to study entry.
• Have received an HIV vaccine within 3 months prior to study entry.
• Are taking foscarnet, hydroxyurea, or other drugs that work against HIV.
• Have taken certain medications such as astemizole, cisapride, dihydroergotamine, ergotamine, ganciclovir, interferon-alpha, midazolam, terfenadine, and triazolam within 21 days of study entry.
• Abuse alcohol or drugs.
• Are unable to complete the whole study.