Despite the advent of highly effective prevention tools such as HIV pre-exposure prophylaxis 1 (PrEP), Black men who have sex with men (MSM) continue to have the highest incidence of new HIV diagnoses in the US. The risk of onward HIV transmission is reduced to zero in HIV-positive individuals who are virally suppressed; however, Black MSM are least likely to be engaged in care or to be suppressed. Many Black MSM face multiple stigmas (e.g., racism, homophobia) and rejection from their biological families, but some have found refuge in the House Ball Community (HBC)—a national network of Black LGBT kinship commitments (families) that provide (informal) care giving, affirmation and survival skills-building for its members. Regarding skills- building and HIV prevention, Many Men Many Voices (3MV) is a six-session, group-level behavioral intervention and is the only “best evidence” intervention for Black MSM. Family-based interventions have shown HIV prevention efficacy; however, 3MV is not a family-based intervention. In 3MV, HIV-negative Black MSM are recruited into artificial group settings with individuals with whom they may have little social relationship. 3MV neither leverages the connections and commitments nor addresses the variability in HIV- status that exists in house ball families., 3MV requires adaptation to be more responsive to this social structure and dynamic. Our goal in this clinical trial planning grant is to prepare for a cluster randomized controlled trial (CRCT) to test the effectiveness of the modified 3MV vs. standard of care in reducing new HIV infections and increasing rates of viral suppression among Black MSM in HBC families. Based on our formative work, that MSM social networks predict HIV prevention behaviors and that HBC family cultural norms primed for communication about HIV prevention and treatment, our central hypothesis is that a modified 3MV intervention incorporating family asset-building will have an amplifying effect on HIV prevention and treatment outcomes. We will investigate this hypothesis with the specific aims: Aim 1: Conduct formative research to identify key modifications to the 3MV intervention manual and implementation protocol. The eight-step ADAPT22ITT model will guide our approach to modifying 3MV into Our Family Our Voices (OFOV), which accommodates the lived experience of HBC families. Aim 2: Conduct a pilot CRCT to determine the feasibility and acceptability of the modified 3MV trial protocol (OFOV) vs. waitlisted standard of care control. We will determine the feasibility/acceptability of OFOV and the CRCT design (n=6 families; 100 individuals) with NYC HBC families. This study will provide necessary data to design and conduct a full-scale CRCT effectiveness trial of OFOV on HIV prevention and care outcomes in Black MSM. The HBC is a large, yet underserved community within the LGBT community. By precision-tailoring an evidence-based intervention for the HBC, our research to improve HIV testin...