Integrating long-acting injectable PrEP into addiction street medicine: Design and feasibility of peer- and practitioner-facilitated engagement models

About This Grant

Project Abstract/Summary This Type 1 R34 implementation research pilot will provide critical, highly sought data to determine whether the unique and innovative biomedical profile of lenacapavir (LEN) pre-exposure prophylaxis (PrEP) is feasible and acceptable to people who use drugs (PWUD) in two street medicine contexts. PWUD remain vulnerable to HIV outbreaks in communities like Everett (Snohomish County), Washington, which lack the extensive HIV prevention infrastructure found in major urban centers. While twice-yearly, long-acting injectable LEN offers a promising advance by reducing dosing burden relative to daily oral or bi-monthly injectable formulations, its actual public health impact will depend on rigorously addressing barriers to LEN engagement, follow-up, and acceptability in real-world settings. This study meets a critical implementation gap regarding how workforce composition, same-day access, and differentiated mobile engagement models may influence LEN uptake and continuation among the most vulnerable PWUD. The project leverages two established, low-barrier mobile outreach programs in Everett: the Emergency Mobile Opioid Team Everett (EMOTE), offering immediate linkage to substance use and mental health treatment to all-comers and led by peers with lived experience in drug use and exchange sex; and the Harm Reduction Center (HRC) street medicine van, offering street-based advanced wound care, buprenorphine, phlebotomy, infectious disease testing/treatment and other medical services, and led by medical practitioners. In Aim 1 we will conduct formative, iterative work guided by the Consolidated Framework 2.0 for Implementation Research (CFIR 2.0). We will convene a Community Advisory Board and focus groups to co-design two tailored PrEP engagement models, each maximizing unique traits of EMOTE or HRC (EMOTE-PrEP and HRC-PrEP) to address LEN messaging, initiation, and retention for PWUD. In Aim 2, we will pilot these models by screening approximately 300 clients and enrolling about 70 eligible participants, with an anticipated 20 LEN initiations across both settings, to assess feasibility, acceptability, and PrEP cascade outcomes. Initiation and 6-month retention will be treated as implementation signals rather than efficacy endpoints. In Aim 3, qualitative interviews with participants who initiate, decline, or discontinue LEN will examine mechanisms influencing engagement, including trust, messenger effects (peer versus practitioner), perceived burden, and decision-making. Without evidence to inform engagement and retention strategies that support both initial uptake and six-month follow-up, the unique advantages of long- acting LEN PrEP will fail to reach the populations most vulnerable to outbreaks. Findings will have a significant public health impact, setting the stage for a fully powered trial of scalable LEN PrEP engagement and retention strategies for PWUD.