ART-free HIV-1 remission in children with in-utero HIV-1 after very early ART (IMPAACT P1115): a multicentre, open-label, phase 1/2 proof-of-concept study.

BACKGROUND We hypothesised that initiating antiretroviral therapy (ART) soon after birth could limit HIV-1 reservoirs and promote ART-free remission. This study aims to assess remission in children with in-utero HIV-1 infection who received very early ART as neonates by performing analytical treatment interruption (ATI). METHODS IMPAACT P1115 is an ongoing, open-label, proof-of-concept study at 30 research sites in 11 countries across Africa, Asia, and the Americas. Neonates (≥34 weeks gestational age) at high risk for in-utero HIV-1 were eligible. Neonates born to mothers with untreated HIV-1 (cohort 1) or mothers who might have been on ART (cohort 2) initiated three-drug oral nevirapine-based ART (6mg/kg per dose orally twice a day) within 48 h of birth (cohort 1), three-drug nevirapine-based prophylaxis (≥8 mg/kg per dose orally once a day), or nevirapine-based ART after HIV-1 diagnosis by age 10 days (cohort 2). Coformulated ritonavir 75 mg/m2 and lopinavir 300 mg/m2 orally twice a day was added when age appropriate for those with confirmed in-utero HIV-1. Nevirapine was discontinued 12 weeks after two consecutive plasma viral loads were below the assay limit. Children at least 2 years of age maintaining undetectable HIV-1 RNA since week 48 and who tested HIV-1 antibody negative, HIV-1 DNA not detected, and normal CD4 count and percentage qualified for ATI. The primary outcome was ART-free remission, defined as no HIV-1 RNA in plasma for 48 weeks or more off ART. A two-sided exact 95% CI was calculated to estimate the probability of remission. This study is registered with ClinicalTrials.gov (NCT02140255). FINDINGS Among 54 children with in-utero HIV-1 enrolled between Jan 23, 2015, and Dec 14, 2017, six (11%) children (four girls, two boys; one in cohort 1, five in cohort 2) met criteria and underwent ATI at a median age of 5·5 years. Two children had early rebound at 3·4 weeks and 9·4 weeks. Four reached ART-free remission (67%; exact 95% CI 22-96), one of whom had late viral rebound at 79·3 weeks. All three children with viral rebound successfully resuppressed HIV-1 RNA below the assay limit on ART. Mild symptoms of acute retroviral syndrome occurred in two participants during rebound and resolved with ART resumption. INTERPRETATION This study shows that ART-free remission for 48 weeks or longer is achievable with very early ART in children with in-utero HIV-1, but close monitoring for viral rebound and acute retroviral syndrome during ATI is needed. These findings, observed in resource-constrained countries, exhibit the feasibility of testing at birth and initiating very early ART, show the potential to limit HIV-1 reservoirs for ART-free remission, and inform future remission strategies. FUNDING The US National Institute of Allergy and Infectious Diseases, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, and the US National Institute of Mental Health.