This study is designed to test if a sequential protease-inhibitor (PI) - / nevirapine (NVP) -based regimen is effective for the treatment of HIV-infected children when previous NVP exposure has occurred as part of programs to prevent mother-to-child transmission (pMTCT).

The wide use of NVP in pMTCT-prophylaxis may result in resistance to NNRTI and concomitantly limits the use of these drugs for the treatment of HIV-infected children. To avoid restricting treatment options for children, it is desirable to preserve NVP for both pMTCT and first line treatment. This study will therefore test whether resistance-caused treatment failures of HIV-infected and previously NVP-exposed children can be avoided if the NVP treatment is preceded by an initial PI-based regimen.

Comparison: HIV-infected children less than 24 months of age, exposed to any pMTCT regimen that included NVP and who achieve and maintain viral suppression for at least 3 months with a PI-based regimen will be randomized to one of the two groups: (1) to continue on PI-containing regimen or (2) to be switched off the PI-containing regimen onto the NVP-containing regimen. The study outcome will be proportions in the two groups who have complete virologic suppression at 6 months after randomization.

Inclusion Criteria:

• NVP-exposure as part of pMTCT-prophylaxis around delivery
• HIV-positive
• Eligible for treatment
• Plans to stay in the area for the next 6 months

Exclusion Criteria:

• Already on anti-retroviral treatment
• History of toxicity to perinatal NVP
• Grade 3 or greater elevation of liver function tests
• Being treated for a severe acute opportunistic infection or tumor