RESTORE (Recovery and Engagement for STimulant users On Re-entry) - Project Summary/Abstract: Stimulant use (cocaine/ methamphetamine) has a major impact on HIV transmission and acquisition. Justice- involved individuals are more likely to have stimulant use disorders and be at risk or living with HIV than the general population, face interruptions in HIV treatment (antiretroviral therapy (ART)) and have limited access to HIV pre-exposure prophylaxis (PrEP). There is thus a critical need for effective interventions that reduce stimulant use and potentially improve HIV viral suppression (VS) and PrEP initation and retention, particularly among justice-involved groups. The most successful treatment for stimulant use disorder to date is contingency management (CM), shown to reduce stimulant use and HIV risk behaviors, though implementation has been limited for justice-involved people due to competing priorities (transportation, housing, probation) and practical challenges of providing CM (frequent drug testing, trained staff, incentive management). DynamiCare is an FDA- approved mobile app that delivers patient-centered behavioral CM and has been shown to reduce biological and self-reported assessments of stimulant and other substance use, however it is unknown if it could improve PrEP/ART initiation for persons with stimulant use disorder at risk or living with HIV. Thus, in response to NIDA RFA-DA-23-008: Stimulants and HIV, we propose the RESTORE study: Recovery and Engagement for Stimulant Users on Re-entry. Guided by the Exploration Preparation Implementation Sustainment (EPIS) framework, we will assess if the addition of personalized CM via the DynamiCare app to a previously protocolized patient navigator (PN) (“DynamiCare-plus”) intervention improves initiation of PrEP/ART and reduces stimulant use. The Specific Aims are: Aim 1 (R61): To conduct a pilot assessment of DynamiCare-plus for persons at risk or living with HIV with DSM-5 stimulant use disorders (methamphetamine/cocaine) being released to the community from a closed justice setting (jail/ prison/ justice-mandated substance use program). N=40 adults in Dallas, TX and CT will be randomized 1:1 to DynamiCare-plus compared to enhanced treatment as usual (ETAU) (PN + smartphone) for 6 months to assess acceptability, feasibility and preliminary effectiveness: proportion who (1) initiate PrEP/ART; and (2) achieve/maintain VS (VL < 200 copies/mL) for those with HIV; Aim 2 (R33): The R61 pilot will inform a type 1 hybrid implementation effectiveness randomized controlled trial of DynamiCare- plus v. ETAU among 252 participants with the same eligiblity as the R61 to assess the primary outcome of initiation/reinitiation of PrEP/ART followed for 15 months, with a 12 month intervention period. Secondary outcomes include stimulant and other substance use, overdose, PrEP/ART/SUD retention, HIV risk behaviors, VS, Quality of life, and recidivism; Aim 2.1: Examine implementation of the intervention. Aim 2.2: Conduct cost analyses of the intervention compared to control. The Dynamicare app is mobile, adaptable and scalable, and combined with PN (DynamiCare-plus) has the potential to have a major impact on HIV treatment and prevention for justice-involved people with stimulant use disorder.