PROJECT SUMMARY MSM remain disparately impacted by HIV, with only 35% of US MSM with indications for PrEP having ever used PrEP. Meth use is an established and persistent driver of HIV incidence for MSM, with up to 33% of incident HIV infections in MSM attributable to stimulant use. There is increasing interest in delivering HIV prevention interventions via a mobile health (mHealth) platform, while implementing PrEP, to replicate the successes of mHealth delivery among meth-using MSM living with HIV. We seek to address this gap by evaluating the combination of state-of-the-art, multi-modal pharmaco-behavioral interventions for the greatest improvement in PrEP adherence (i.e., the “CHAMPION”). CHAMPION will combine two mobile health technologies: (PREPAPP with virtual cognitive behavioral therapy [CBT4CBT]). We aim to (1) Evaluate the feasibility and acceptability of CHAMPION, compared to a waitlist control, and (2) Evaluate the preliminary efficacy of CHAMPION on increasing PrEP adherence, compared to a waitlist control. To advance these aims, we will enroll 100 HIV-negative MSM who use meth in a 6-month randomized-controlled trial of PrEPAPP and CBT4CBT with a 3-month waitlist control. Eligible participants include those with meth use disorder (MUD). Enrolled participants will be randomized to either receive the CHAMPION intervention package, or have a 3- month usual care waitlist control. Behavioral assessments will be administered monthly and objective measures of PrEP adherence will be examined using dried blood spot (DBS) samples collected every 3 months. Feasibility will be assessed through treatment retention and engagement rates at month 3 and 6 follow-up. Preliminary efficacy will be assessed using DBS endpoints. In exploratory aims, we will examine preliminary efficacy on meth use and sexual risk behavior. This study will focus on MSM because meth is highly prevalent in this population and meth has been linked to HIV transmission and acquisition among MSM. If CHAMPION is efficacious, it may ultimately expand available strategies for MSM to reduce meth use, increase PrEP adherence, and reduce meth-associated sexual risk behaviors.