In a previous study, the study team found that first-line anti-TB therapy had minimal effect on EFV pharmacokinetics (PK) at the population level, but children with TB/HIV coinfection on anti-TB therapy had a trend towards worse virologic outcome compared to those with only HIV infection. Due to the small sample size, the study team were unable to examined the patient factors contributing to the poor virologic response. The study team hypothesized that virologic suppression rates on EFV-based therapy is significantly lower in children with TB/HIV coinfection compared to those with HIV alone. In addition, virologic response will be dependent EFV plasma concentrations, CYP2B6 516 G\>T genotype and/or adherence level. This hypothesis is based on the premise that extremes (low and high EFV concentration, respectively) could lead to virologic failure because of lack of efficacy or intolerable side effects leading to poor adherence. The current study will investigate the effect of anti-TB therapy, CYP2B6 genotype and pharmacokinetically determined adherence level on virologic response in children with TB/HIV coinfection treated with EFV-based ART.
