Long-term virological outcome in children on antiretroviral therapy in the UK and Ireland

OBJECTIVE: To assess factors at the start of antiretroviral therapy (ART) associated with long-term virological response in children. DESIGN: Multicentre national cohort. METHODS: Factors associated with viral load below 400 copies/ml by 12 months and virologic failure among children starting 3/4-drug ART in the UK/Irish Collaborative HIV Paediatric Study were assessed using Poisson models. RESULTS: Nine hundred and ninety-seven children started ART at a median age of 7.7 years (inter-quartile range 2.9–11.7), 251 (25%) below 3 years: 411 (41%) with efavirenz and two nucleoside reverse transcriptase inhibitors (EFV + 2NRTIs), 264 (26%) with nevirapine and two NRTIs (NVP + 2NRTIs), 119 (12%; 106 NVP, 13 EFV) with non-nucleoside reverse transcriptase inhibitor and three NRTIs (NNRTI + 3NRTIs), and 203 (20%) with boosted protease inhibitor-based regimens. Median follow-up after ART initiation was 5.7 (3.0–8.8) years. Viral load was less than 400 copies/ml by 12 months in 92% [95% confidence interval (CI) 91–94%] of the children. Time to suppression was similar across regimens (P = 0.10), but faster over calendar time, with older age and lower baseline viral load. Three hundred and thirty-nine (34%) children experienced virological failure. Although progression to failure varied by regimen (P < 0.001) and was fastest for NVP + 2NRTIs regimens, risk after 2 years on therapy was similar for EFV + 2NRTIs and NVP + 2NRTIs, and lowest for NNRTI + 3NRTIs regimens (P-interaction = 0.03). Older age, earlier calendar periods and maternal ART exposure were associated with increased failure risk. Early treatment discontinuation for toxicity occurred more frequently for NVP-based regimens, but 5-year cumulative incidence was similar: 6.1% (95% CI 3.9–8.9%) NVP, 8.3% (95% CI 5.6–11.6) EFV, and 9.8% (95% CI 5.7–15.3%) protease inhibitor-based regimens (P = 0.48). CONCLUSION: Viral load suppression by 12 months was high with all regimens. NVP + 3NRTIs regimens were particularly efficacious in the longer term and may be a good alternative to protease inhibitor-based ART in young children.