CROI 2018 Abstract eBook

Abstract eBook

Poster Abstracts

Results: In the reference scenario, the disparity ratio of BMSM to WMSM incidence rates was 4.71. In the second, “as-observed” scenario, 8.4% of BMSM and 23.4% of WMSM were predicted to be on PrEP. Compared to no PrEP, incidence at year 10 was lower for both BMSM (HR = 0.77) and WMSM (HR = 0.56), with 14.1% and 33.1% of cumulative infections averted respectively. This stronger benefit for WMSM increased the disparity ratio to 6.31. In the third, equal parameters scenario, the disparity ratio (4.74) returned towards the reference scenario value, with slightly higher infections averted for WMSM (35.6% vs 29.6%) as a function of their higher levels of PrEP indications. With BMSM continuum parameters set to 120% of WMSM values, the hazard ratio for BMSM was stronger than for WMSM (0.40 vs 0.50), with the disparity ratio below the reference scenario (2.91). Conclusion: Poorer levels of PrEP awareness, access, prescription, and adherence could limit the population-level prevention effects of HIV PrEP for BMSM, leading to higher than current disparities albeit at lower incidence rates for both races. Reducing HIV disparities with PrEP will require addressing race-specific gaps along the PrEP continuum to improve rates of PrEP initiation, adherence, and retention for BMSM in the United States.

Poster Abstracts

1150 IMPROVING STATEWIDE PRE-EXPOSURE PROPHYLAXIS IMPLEMENTATION AMONG MSM

Jason Gantenberg 1 , Maximilian King 1 , Madeline C. Montgomery 2 , Omar Galarraga 1 , Mattia Prosperi 3 , Brandon D. Marshall 1 , Philip A. Chan 2 1 Brown University, Providence, RI, USA, 2 The Miriam Hospital, Providence, RI, USA, 3 University of Florida, Gainesville, FL, USA Background: Daily oral PrEP is effective in reducing HIV transmission, yet uptake among men who have sex with men (MSM) has been slow in the United States. In this study, we sought to identify strategies that would yield the highest reduction in HIV incidence among MSM to help guide a statewide implementation effort and achieve the National HIV/AIDS Strategy goal of reducing new diagnoses by 25% over 10 years. Methods: We used a discrete-time, stochastic agent-based model representing all MSM aged 15–74 in Rhode Island ( N = 25,000), a state with approximately 4–5% HIV prevalence among MSM. We simulated the following scenarios in which different populations of MSMwere engaged for PrEP uptake: 1) Current Patient Population - selection based on distributions of age and partner degree among actual patients in a PrEP program implemented according to CDC guidelines; 2) Random - random allocation, all HIV-negative MSM eligible; 3) Partner Number (PN) - Annual partner number greater than 5 or 10. The model was calibrated to reproduce statewide prevalence from 2009 through 2014. For each simulation, PrEP was implemented after this 6-year lead-in period and maintained at a fixed coverage level for the next 10 years. Scenarios were simulated 1,000 times each, with 5–30% PrEP coverage of the HIV-negative population. Results: From 2015–2025, a median of 826 new HIV infections were predicted across the entire population in the absence of PrEP. At 15% PrEP coverage of HIV-negative MSM, 3 of the 4 scenarios achieved a greater than 25% reduction in cumulative incidence, exceeding the National HIV/AIDS Strategy goal in this timeframe (Table). A 25% reduction in the median cumulative incidence, relative to the scenario without PrEP, was apparent after 9.1, 6.8, and 3.4 years in the Current Patient Population, PN > 5, and PN > 10 scenarios, respectively. The only scenario to approach the goal at lower PrEP coverage was the PN > 10

1149 THE PrEP CARE CONTINUUM AND HIV RACIAL DISPARITIES AMONG MEN WHO HAVE SEX WITH MEN Samuel Jenness 1 , Kevin Maloney 1 , Dawn K. Smith 2 , Karen W. Hoover 2 , Steven M. Goodreau 3 , Kevin Weiss 1 , Eli Rosenberg 1 , Patrick S. Sullivan 1 1 Emory University, Atlanta, GA, USA, 2 CDC, Atlanta, GA, USA, 3 University of Washington, Seattle, WA, USA Background: HIV preexposure prophylaxis (PrEP) could reduce the racial disparities in HIV incidence among black men who have sex with men (BMSM), particularly in the Southeast US where the disparities are greatest. Achieving this goal will depend on race-specific rates of movement through the PrEP continuum of care from awareness to adherence and retention. Methods: We expanded our mathematical model of HIV transmission for MSM, which simulates PrEP based on the bio-behavioral indications of CDC’s clinical practice guidelines, to include race-stratified transitions through the PrEP continuum from awareness to access to prescription to adherence to retention. Continuum parameters - consistently equal to or poorer for BMSM compared to white MSM (WMSM) - were estimated based on our Atlanta-based HIV incidence cohorts and published PrEP open-label studies. Models were calibrated to race-specific prevalence in these cohorts. We simulated four scenarios over a ten-year period: 1) no-PrEP (reference); 2) PrEP with the observed race-specific continuum parameters; 3) PrEP with BMSM parameters set to WMSM values; and 4) PrEP with BMSM parameters set to 20% higher than WMSM values.

CROI 2018 445