Optimizing PrEP Implementation and Cost-effectiveness among Individuals with a Substance Use Disorder

In the US most annual newly diagnosed HIV infections are among substance-using individuals,1 and many are diagnosed with a substance use disorder (SUD).2-5 The presence of a SUD substantially increases risk of HIV infection.6-16 Although PrEP is highly effective, initiation, adherence, and persistence are exclusively behavioral outcomes, and the biomedical benefits of PrEP are abrogated by substance use. SUD is also associated with reduced quality-of-life, and increased overdose deaths, utilization of high-cost healthcare services, engagement in a street economy, and incarceration.17-26 This application builds upon the highly promising findings from our open-label Phase I A.S.K.- PrEP (Assistance Services Knowledge-PrEP) pilot, which utilized PrEP navigation with text message support to increase PrEP initiation. The Phase II study will implement a RCT with a Stepped Care design of ASK-PREP vs. standard of care (SOC) to determine optimal intervention response (N=285) for initiation, adherence, and persistence. Participants will be randomized (3:1) to Stepped Care (n=214) or SOC (n=71). Participants in the Stepped Care arm will receive the same ASK-PrEP intervention that was delivered in the pilot study and will be assessed at 3- months for intervention response; responders will be maintained in ASK-PrEP, while non-responders will receive added attention to their SUD via contingency management (CM). Non-responders will be re-randomized (1:1) to either a) receive ASK-PrEP + CM, or b) shift the primary focus to their SUD (CM alone). The ASK-PrEP navigation intervention is based on mechanisms of the Reasoned Action Approach, text message support is based in Social Support Theory, and CM is based on behavioral economics. The specific aims are to: 1) Evaluate a Stepped Care approach promoting PrEP initiation, adherence, persistence, and reductions in substance use; 2) Estimate the cost of implementing and sustaining each intervention and conduct a cost-effectiveness analysis to determine the value of each intervention relative to SOC and to each other; Secondary Aim 1) Determine the effects of specific substances as moderators of outcomes; and Exploratory Aim) Evaluate intervention engagement and response by chosen PrEP modality (oral daily or long-acting injectable). The “intent-to-treat” RCT uses repeated assessments at baseline and at 3-, 6-, 9-, and 12-months post enrollment.