The purpose of this study is to see if it is safe and effective to give HIV-infected patients a new combination of anti-HIV drugs taken once daily.

Patients receive a treatment regimen of adefovir dipivoxil, didanosine, efavirenz, and lamivudine for 48 weeks. During the study, patients are evaluated for changes from baseline in plasma HIV-1 RNA and lymphocyte subsets and for the development of adverse experiences and laboratory toxicities. At Weeks 8, 12, 24, and 48, patients are assessed for adherence to study treatment with a questionnaire. Patients who experience virologic failure are discontinued from the study. Patients who experience treatment intolerance may have their antiretroviral treatment regimens changed. After Week 48, patients with documented virologic response are eligible to continue receiving study treatment.

Inclusion Criteria

You may be eligible for this study if you:

• Are HIV-positive.
• Are at least 13 years old (need consent of parent or guardian if under 18).
• Have an HIV count of 5,000 copies/ml or more within 30 days prior to study entry.
• Have a CD4+ count of 50 cells/mm3 or more.

Exclusion Criteria

You will not be eligible for this study if you:

• Are diagnosed with hepatitis within 30 days prior to study entry.
• Have certain serious medical conditions, including an AIDS-defining clinical condition.
• Received chemotherapy or radiation therapy within 30 days of study entry.
• Have taken any nucleoside reverse transcriptase inhibitors (NRTIs) for more than 2 weeks.
• Have ever taken 3TC.
• Have ever taken any non-nucleoside reverse transcriptase inhibitors (NNRTIs).
• Have taken medications that affect your immune system within 30 days prior to study entry.
• Have received a vaccine within 30 days prior to study entry.
• Are enrolled in another anti-HIV drug study while participating in this study.
• Abuse alcohol or drugs.
• Are pregnant or breast-feeding.