A Phase I/II Study of Invirase® Boosted With Ritonavir in HIV Infected Infants and Children 4 Months to Less Than 6 Years Old

This single arm study will assess the pharmacokinetics, safety and activity of saquinavir (Invirase hard gel capsules, film coated tablets or opened capsules) boosted by combination with ritonavir, in HIV-1 infected infants and children between the ages of 4 months and 6 years. Patients will commence treatment with saquinavir 50mg/kg bid plus ritonavir 2.5mg/kg or 3.0mg/kg (dependent on body weight), and a background antiretroviral regimen. If drug exposures are found to be dissimilar to those previously seen in older children and adults, or are associated with toxicities, subsequent dose adjustments will be made. The anticipated time on study treatment is 3-12 months, and the target sample size is \<100 individuals.