This trial tests the safety and effectiveness of the early use of combinations of anti-HIV drugs in HIV-infected infants and young children in an effort to block virus growth and preserve normal immune functions.

Various anti-HIV drug combinations need to be tested in order to find the best way to treat infants and children who have been infected with HIV during birth.

This study examines the antiretroviral activity of ZDV/3TC/NVP in vertically-infected infants and children aged 15 days up to 2 years, and ZDV/3TC/NVP/ABC in vertically-infected infants and children aged 30 days up to 2 years. This study will assess HIV-1 and CD4/CD8 T-cell kinetics, activation, and maturation. It will also test the concept that early (younger than 3 months of age) use of potent, combination antiretroviral therapy will allow the long-term control of viral replication with preservation of normal immune function. [AS PER AMENDMENT 3/11/98: This study will also examine the antiretroviral activity of ZDV/3TC/NVP/NFV in vertically infected infants and children.]

This is a 2-part Phase I/II, open-label trial in HIV-infected infants. Part A assesses the triple combination of ZDV, 3TC, and NVP. Four to eight patients are enrolled in each age cohort (Cohort 1: at least 15 days, no more than 3 months; Cohort 2: over 3 months, no more than 2 years). Part B assesses the quadruple combination of ZDV, 3TC, NVP, and ABC. Eight patients are enrolled in each age cohort (Cohort 3: at least 30 days, no more than 3 months; Cohort 4: over 3 months, no more than 2 years). [AS PER AMENDMENT 3/11/98: This study is now a 3-part Phase I/II trial. Parts A and B are as above. Part C will assess the quadruple regimen of d4T, 3TC, NVP and NFV. Up to 8 patients will be enrolled in each age cohort (Cohort 5: at least 15 days, no more than 3 months; Cohort 6: over 3 months, no more than 2 years). If 3 of 4 patients in either cohort of Part B do not achieve plasma RNA less than 1,000 copies/ml after 16 weeks of quadruple therapy, enrollment of patients to that cohort will stop and enrollment of 8 patients to the corresponding cohort in Part C will begin. For Part C, patients whose RNA level is no more than 1,000 copies/ml at Week 16 will remain on assigned treatment until Week 104. If at any time between Weeks 16 and 104 a patient's RNA level increases to greater than 1,000 copies/ml, plasma RNA will be repeated within 1 week. If both RNA levels are greater than 1,000 copies/ml, the patient will discontinue study treatment and be followed every 12 weeks for 1 year.] [AS PER AMENDMENT 4/14/99: The study has been extended for an additional 96 weeks for children with continued suppression of viral replication (RNA less than 400 copies/ml) at Week 104. If at any time between Week 12 or 16 and Week 200 a patient's RNA level increases to greater than 1,000 copies/ml, plasma RNA will be repeated within 1 week. If both RNA levels are above 1,000 copies/ml, the patient will discontinue treatment for best available therapy and be followed every 12 weeks for 1 year following the discontinuation of study treatment.] [AS PER AMENDMENT 9/16/99: An additional cohort (Cohort 7) of 5 to 10 patients has been added. Cohort 7 includes patients between 15 days and 3 months of age. Cohort 7 patients who experience suppression of viral replication at Week 104 are followed through Week 200.]

Inclusion Criteria

Children may be eligible for this study if they:

• Are 15 days to 2 years old.
• Have consent of parent or legal guardian.
• Are HIV-positive.

Exclusion Criteria

Children will not be eligible for this study if they:

• Have certain infections which require treatment during the study.
• Have received certain medications.