The aim of the study was to assess the prevalence, predictors and patterns of genotypic resistance mutations in children after failure of World Health Organization-recommended initial nonnucleoside reverse transcriptase inhibitor (NNRTI)-based treatment regimens.
We carried out a multicentre retrospective study of genotyping tests performed for all HIV-infected children at eight paediatric centres in Thailand who experienced failure of NNRTI therapy at a time when virological monitoring was not routinely available.
One hundred and twenty children were included in the study. Their median age (interquartile range) was 9.1 (6.8–11.0) years, the median duration of their NNRTI regimens was 23.7 (15.7–32.6) months, their median CD4 percentage was 12% (4–20%), and their median plasma HIV RNA at the time of genotype testing was 4.8 (4.3–5.2) log10 HIV-1 RNA copies/mL. The nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations found were as follows: 85% of the children had M184V/I, 23% had at least four thymidine analogue mutations, 12% had the Q151M complex, 5% had K65R, and 1% had the 69 insertion. Ninety-eight per cent of the children had at least one NNRTI resistance mutation, and 48% had etravirine mutation-weighted scores ≥4. CD4 percentage <15% prior to switching regimens [odds ratio (OR) 5.49; 95% confidence interval (CI) 2.02–14.93] and plasma HIV RNA>5 log10 copies/mL (OR 2.46; 95% CI 1.04–5.82) were independent predictors of at least four thymidine analogue mutations, the Q151M complex or the 69 insertion.
In settings without routine viral load monitoring, second-line antiretroviral therapy regimens should be designed assuming that clinical or immunological failure is associated with high rates of multi-NRTI resistance and NNRTI resistance, including resistance to etravirine.