PROJECT SUMMARY Scalable interventions that facilitate adherence to HIV PrEP are urgently needed to address the alarming HIV incidence in Black MSM. In 2020, only 26% of Black MSM in the U.S. used PrEP even though they represented 40% of HIV diagnoses. There are multi-level barriers to PrEP adherence among Black MSM, including interpersonal and institutional intersectional stigmas. To optimize equity in PrEP coverage, Black MSM must have access to service options that reduce their exposure to these stigmas. Many Men Many Voices (3MV) is a group-level behavioral intervention that demonstrated efficacy for increasing healthcare seeking behaviors in Black MSM. Client-centered care coordination (C4) addresses social stigma through a service model that trains staff to deliver autonomy-supportive care and addresses structural stigma via an integrated online platform to improve the continuity of coordination between service providers. Our goal is to combine two evidence-based interventions into a multi-level integrated strategy that directly addresses interpersonal stigma via 3MV, extends 3MV effects into service-delivery settings by training staff on key concepts, and then addresses structural stigma by linking men to a network of services via the online C4 platform. We will pursue the following aims with 2 implementing agencies serving Black MSM: (1) determine the efficacy of an integrated 3MV+ C4 for increasing PrEP adherence; (2) ascertain the optimal dose of C4 implementation for maximizing its effect on PrEP adherence; (3) identify the critical leverage points in the implementation ecosystem to target for change. 48 egocentric networks of Black MSM (N=480; mean network size n=10) will be recruited in Dallas/Ft. Worth and Miami/Ft. Lauderdale. Networks will all begin with a 3-month control phase and be randomized into either the C4 arm or the C4+3MV arm. The Learn-as-you-go (LAGO) statistical methodology will be used to optimize the strategy and associated costs by generating statistical recommendations for modifying pre- specified components of C4. Qualitative interviews will explore the factors affecting implementation at scale. Lastly, we will develop a policy brief accounting for the political economy and non-economic welfare effects of 3MV+C4. This study advances HIV prevention science by generating evidence for an intervention that will contribute to racial equity in the impact of PrEP on the HIV epidemic. Our research also uses innovative statistical and interdisciplinary methods that allow us to maximize 3MV and C4’s effects on adherence by: (1) optimizing elements observed to be contributing to increases in adherence and (2) streamlining excess elements to reduce implementation time and costs; thus, enhancing scale-up potential in EHE communities.