Lowenthal EDChapman JOhrenschall RCalabrese KBaltrusaitis KHeckman BYin DEAgwu ALHarrington CVan Solingen-Ristea RMMcCoig CCAdeyeye AKneebone JChounta VSmith-Anderson CCamacho-Gonzalez AD'Angelo JBearden ACrauwels HHuang JBuisson SMilligan RWard SBolton-Moore CGaur AH2025-05-232024-Apr10.1016/S2352-3018(23)00301-6https://pubs.cidrz.org/handle/123456789/10796BACKGROUND: Long-acting injectable cabotegravir and rilpivirine have demonstrated safety, acceptability, and efficacy in adults living with HIV-1. The IMPAACT 2017 study (MOCHA study) was the first to use these injectable formulations in adolescents (aged 12-17 years) living with HIV-1. Herein, we report acceptability and tolerability outcomes in cohort 1 of the study. METHODS: In this a secondary analysis of a phase 1/2, multicentre, open-label, non-comparative dose-finding study, with continuation of pre-study oral combination antiretroviral treatment (ART), 55 adolescents living with HIV-1 were enrolled to receive sequential doses of either long-acting cabotegravir or rilpivirine and 52 received at least two injections. Participants had a body weight greater than 35 kg and BMI less than 31·5 kg/m FINDINGS: Between March 19, 2019, and Nov 25, 2021, 55 participants were enrolled into cohort 1. Using the six-point face scale, 43 (83%) of participants at week 4 and 38 (73%) at week 8 reported that the injection caused "no hurt" or "hurts little bit", while only a single (2%) participant for each week rated the pain as one of the two highest pain levels. Quality of life was not diminished by the addition of one injectable antiretroviral. In-depth interviews revealed that parents and caregivers in the USA frequently had more hesitancy than adolescents about use of long-acting formulations, but parental acceptance was higher after their children received injections. INTERPRETATION: High acceptability and tolerability of long-acting cabotegravir or rilpivirine injections suggests that these are likely to be favoured treatment options for some adolescents living with HIV. FUNDING: National Institutes of Health and ViiV Healthcare.