This study compares the safety and effectiveness of continuing your current anti-HIV medications to that of adding or switching some of your anti-HIV medications. It will follow the effect of these medication changes, including the addition of hydroxyurea (HU), on long-term viral suppression. Other medications which may be added include didanosine (ddI) and/or stavudine (d4T).

Patients receiving combination antiretroviral therapy with indinavir (IDV), zidovudine (ZDV)(or d4T) and lamivudine (3TC) show viral suppression for two years or more. Discontinuation of one or two of these drugs results in prompt loss of the viral suppression. Other studies show that addition of HU to some reverse transcriptase inhibitor treatments results in increased antiviral effects. This study will provide further information on the effect of adding HU to a treatment regimen with respect to long-term viral suppression.

Previous ACTG studies show that discontinuation of one or two of a three-drug regimen (IDV, ZDV, 3TC) leads to prompt loss of viral suppression in the plasma. In this trial, it will be determined whether adding hydroxyurea (HU) to a suppressive regimen increases long term viral suppression. Important safety information on the tolerance of HU regimen will be characterized in asymptomatic patients with viral suppression.

Patients are equally randomized to one of three arms and receive treatment as follows:Arm A: IDV plus ddI plus d4T plus HU placebo. Arm B: IDV plus ddI plus d4T plus HU. Arm C: IDV plus 3TC/ZDV (or d4T plus 3TC). Patients are monitored every 8 weeks with plasma HIV RNA levels and CD4 cell counts.

Inclusion Criteria

You may be eligible for this study if you:

• Are 13 years or older.
• Have documented HIV-1 infection.
• Are currently receiving combined IDV, ZDV(or D4T), and 3TC for at least 6 consecutive months, resulting in HIV RNA less than 200 copies/ml and CD4 cell count greater than 200 cells/mm3.
• Had a CD4 count greater than 100 cells/mm3 before starting current anti-HIV therapy.
• Are of childbearing age and agree to practice abstinence or use of combined barrier and hormonal methods of birth control during and for 3 months after the study.

Exclusion Criteria

You will not be eligible for this study if you:

• Have taken various medications and have various laboratory results (see technical abstract).
• Have cancer requiring chemotherapy.
• Have an unexplained fever for 7 days or diarrhea for 15 days in the month before the start of the study.
• Had prior peripheral neuropathy or hepatitis.
• Recently underwent radiation, experimental, or infection therapy.
• Are pregnant or breastfeeding.