This study, conducted by M. Kline and colleagues at Baylor College of Medicine, evaluated the safety, antiviral and immunologic effects, and pharmacokinetics of hydroxyurea, given with ddI and/or d4T to symptomatic HIV-infected children. It is among the first to look at the use of HU in children. The children were treated with hydroxyurea (initial dose, 10-20 mg/kg once daily; final dose, 20 mg/kg once daily), added to existing antiretroviral therapy that included ddI and/or d4T, for at least 48 weeks each.

Sixteen children were enrolled, with a mean age of 6.7 years (the range was 1.8 to 13.4 years), and a mean viral load of 4.4 log, and a mean T-cell count of 751. Regimens used with hydroxyurea included d4T/ddI (11 children), ddI (2 children), d4T (1 child), and d4T/3TC (1 child). They were treated for a mean duration of 16 weeks, with 5 of the 16 children (31%) experiencing a greater than 0.5 log drop in viral load by week 4. By week 16, appreciable changes in T-cell count were not observed.

The study found short-term therapy with HU to be safe and effective for some children who add the drug to a stable antiretroviral regimen. It is important to note that hydroxyurea was held temporarily during the first month of therapy in four cases because of neutropenia (low white cell count). However, all patients ultimately resumed hydroxyurea without incident. Finally, pharmacokinetic analysis showed that children may metabolize HU more rapidly than adults, and thus may require larger doses of HU per kilogram of body weight.