Rationale and design of an integrated bio-behavioral approach to improve adherence to pre-exposure prophylaxis and HIV risk reduction among opioid-dependent people who use drugs: The CHRP-BB study

Few primary HIV prevention strategies have successfully integrated both behavioral and biomedical components, with modest HIV risk reduction outcomes among opioid-dependent people who use drugs (PWUD). In response to this unmet need, we developed a brief, bio-behavioral intervention to simultaneously promote PrEP adherence and reduce HIV risk among opioid-dependent PWUD. Using a Hybrid Type I implementation science design, we will examine the efficacy of the integrated bio-behavioral, Community-friendly Health Recovery Program (CHRP-BB) compared to a time-and-attention matched control condition among HIV-negative, opioid-dependent PWUD who are prescribed PrEP and enrolled in a methadone maintenance program (MMP) using a randomized controlled trial (RCT). Participants are assessed at baseline, immediately post-intervention (8 weeks) and follow-ups at weeks 20, 32, and 44 post-intervention. The primary outcome is biomedical (PrEP adherence), with secondary outcomes including behavioral (self-reported drug- and sex-related HIV risk behaviors), ongoing drug use (confirmed with urine drug testing), and related domains of the theoretical information-motivation-behavioral skills (IMB) model of behavior change related to PrEP adherence and HIV-transmission-risk reduction. Additionally, we will conduct a process evaluation of delivery/implementation of the intervention to collect valuable information to be used in future implementation. This study will be among the first prospective trial to test an integrated bio-behavioral intervention to improve adherence to PrEP and HIV risk reduction among opioid-dependent PWUD.