SUSTAIN ABSTRACT Despite decades of research on behavioral interventions to improve management of HIV and alcohol and on the high rates of risk behaviors in emerging adults (ages 18-29), there is only one intervention that has been shown to improve viral burden and alcohol use in young people living with HIV (YPLWH) in full-scale trials with sufficient rigor to be published in JAMA journals. Healthy Choices, was adapted and developmentally tailored for emerging adults to address self-management of risk behaviors and HIV from Motivational Enhancement Therapy, a brief alcohol intervention in SAMHSA’s registry of evidenced-based programs. We will now conduct a hybrid Type 1 comparative effectiveness-implementation trial to develop an adaptive intervention (one where dose and delivery format can be tailored). The first randomization compares an existing brief mHealth MI- based self-management intervention (THRIVE) versus brief mHealth plus a single telehealth session of Health Choices. We move beyond a traditional clinical trial by utilizing a SMART design (Sequential Multiple Assignment Randomized Trial) as an efficient and rigorous way to explore additional questions to optimize interventions and maximize real-world implementation such as: 1) is there a need for an additional THRIVE check-up among YPLWH who report >80% adherence AND no NIAA-defined hazardous drinking after one month (responders); and 2) for YPLWH who report <=80% adherence AND hazardous drinking at 1-month follow-up (non-responders) which is more effective and economical, the remaining three sessions of Healthy Choices are delivered via telehealth versus mHealth. As another innovation, we include behavioral, biomarker and pragmatic outcomes. We plan to recruit a diverse sample of 300 YPLWH across Florida who report any alcohol use and ≤80 percent adherence to antiretroviral treatment (from clinics, community organizations, and social media) and collect data at baseline, 3, 6, and 12 months. The goal of PROJECT SUSTAIN is to optimize Healthy Choices to advance an adaptive and sustainable intervention designed to improve self-management of alcohol and HIV in YPLWH while understanding the context for state-wide implementation and sustainment in an effectiveness-implementation Type 1 Hybrid SMART. The primary aim is to compare THRIVE, an mHealth intervention adapted to target self-management of alcohol and HIV, with THRIVE plus a single telehealth session of Healthy Choices. In a single session we can build motivation for alcohol and HIV management but not address the range of self-management skills. Thus, we also aim to understand the benefit of the remaining three Healthy Choices sessions for non-responders, to compare the effectiveness of delivery of these sessions by telehealth or mHealth, and to determine the benefit of mHealth boosters for responders. Finally, we prepare for state-wide implementation by studying barriers and facilitators from multiple stakeholders using an establ...