Background: The non-nucleoside reverse transcriptase inhibitors (NNRTI) nevirapine (NVP) and efavirenz (EFV) are widely used as part of first line HAART regimens in developing countries. The objective of this study is to determine the efficacy of NNRTI-based HAART among antiretroviral naive HIV-infected children in Thailand.

Methods: A prospective cohort of 92 antiretroviral naive HIV-infected children, who had CD4 count <15% was enrolled  between August 2002 and April 2003. HAART consisting of the NRTI backbone of d4T and 3TC combined with either NVP  or EFV were started in 44 patients (NVP) and 48 patients (EFV) . All patients had been followed for > 24 weeks. Primary endpoints: change in CD4% and cell count, percentage of patients with HIV RNA < 50 copies/ml at week 24. Secondary endpoints: incidence of adverse events, adherence to treatment.

Results: There were 56 boys and 36 girls enrolled in the study with mean age of 7.7 (2 to 13.8) years. Initial median CD4 was 4%, and median CD4 cell count were 103 cells/mm³ among children aged 2 to years and 68 cells/mm³ among children aged 6 years or older. Median HIV RNA at baseline was 5.39 log₁₀ copies/mL with 79 % of patients had HIV RNA > 5log₁₀. The baseline characteristics of the 2 groups were similar. At week-24 median CD4 % increase from baseline was 8%, median CD4 count increased for children aged 2 to 5 years and 6 years or older were 273 cells/mm³ and 203 cells/ mm³, respectively. There was no difference between EFV and NVP regimens in CD4 cells response. At week 24 of treatment, median HIV viral load reduction were 3.64 log₁₀ and 3.28 log₁₀ in EFV and NVP regimens respectively. Percentage of patients with HIV RNA < 50 copies/mL were 73% in EFV compared with 46% in NVP regimens (p = 0.007). Percentage of patients with HIV RNA <400 copies/mL were 96% in EFV compare to 75% in NVP regimens (p  = 0.004). Rash and central nervous system toxicity occurred in EFV regimen, 10% and 21%; compared with NVP regimen, 30% and 2%. Seven patients (8%) had poor adherence defined by taking <95% of drug dosing, 2 in EFV group and 5 in NVP group. Two patients died during follow-up.

Conclusions: This study showed that NNRTI-based HAART is an effective regimen in Thai HIV-infected children despite the initiation in advanced stage of disease. The immunological efficacy was comparable between EFV and NVP regimens, however the EFV-based regimen had better virological outcome than the NVP-based one.

Keywords: HAART in children; NNRTI-based HAART; HAART in developing countries