Drug resistance mutations among South African children living with HIV on WHO-recommended ART regimens.

Hackett, Stephanie; Teasdale, Chloe A; Pals, Sherri; Muttiti, Anthony; Mogashoa, Mary; Chang, Joy; Zeh, Clement; Ramos, Artur; Rivadeneira, Emilia D; DeVos, Joshua; Sleeman, Katrina; Abrams, Elaine J

BACKGROUND Children living with HIV (CLHIV) receiving antiretroviral treatment (ART) in resource limited settings are susceptible to high rates of acquired HIV drug resistance (HIVDR), but few studies include children initiating age-appropriate WHO-recommended first-line regimens. We report data from a cohort of ART-naïve South African children who initiated first-line ART. METHODS ART-eligible CLHIV aged 0-12 years were enrolled from 2012 to 2014 at five public South African facilities and followed for up to 24 months. Enrolled CLHIV received standard of care WHO-recommended first-line ART. At the final study visit, a dried blood spot sample was obtained for viral load and genotypic resistance testing. RESULTS Among 72 successfully genotyped CLHIV, 49 (68.1%) received ABC/3TC/LPV/r, and 23 (31.9%) received ABC/3TC/EFV. All but 2 children on ABC/3TC/LPV/r were <3 years and all CLHIV on ABC/3TC/EFV were ≥3 years. Overall, 80.6% (58/72) had at least one drug resistance mutation (DRM). DRMs to NNRTIs and NRTIs were found among 65% and 51% of all CLHIV, respectively, with no statistical difference by ART regimen. More CLHIV on ABC/3TC/EFV, 47.8% (11/23), were found to have 0 or only 1 effective antiretroviral drug remaining in their current regimen compared to 8.2% (4/49) on ABC/3TC/LPV/r. CONCLUSIONS High levels of NNRTI and NRTI DRMs among CLHIV receiving ABC/3TC/LPV/r suggests a lasting impact of failed PMTCT interventions on DRMs. However, drug susceptibility analysis, reveals that CLHIV with detectable viremia on ABC/3TC/LPV/r are more likely to have maintained at least two effective agents on their current HIV regimen than those on ABC/3TC/EFV.