CROI 2025 Abstract eBook

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Results: From 2019 to 2023, among 1,403 participants with ≥1 STI diagnosis, only 13 (0.93%) were prescribed DoxyPEP (85% male, median age 43, 85% MSM HIV risk factor, 92% had a rectal STI, and 46% had ≥2 STIs within a 12-month period). In any given year 50%-56% of STI cases were DoxyPEP eligible. Overall, there were 3,581 STI diagnoses, of which 2,890 were among MSM/TW (63.4 STI diagnoses/100 person-years). Among the 1,077 MSM or TW who had ≥1 bacterial STI diagnosis, 10% had a VL >200 copies/mL, 68% reported >1 sexual partner in the prior 3 months. Strategies with the lowest NNT were prescribing DoxyPEP for 12 months to PWH with a concurrent STI diagnosis (NNT=2.99 for any STI); with ≥2 STIs (NNT=3.22 for any STI); and to PWH with any STI (NNT=3.89 for concurrent STI diagnoses)(Figure).

p<.001). The ITS revealed a significant three-way interaction between DPEP use, time, and DPEP initiation, p<.001. Conclusions: DPEP uptake continues to increase and bacterial STI incidence among DPEP users declined significantly overall and for each STI including

Oral Abstracts

gonorrhea demonstrating sustained high impact of this intervention in a real world setting. Continued evaluation of DPEP uptake, use, and adherence will be essential as implementation expands. The Doxy-PEP Continuum Among Patients Receiving Care at a Sexual Health Clinic in San Francisco Michael P. Barry 1 , Jason Bena 1 , Jorge Roman 1 , Hyman Scott 2 1 San Francisco AIDS Foundation, San Francisco, CA, USA, 2 San Francisco Department of Public Health, San Francisco, CA, USA Background: In 2024, San Francisco Department of Public Health released updated recommendations for prescribing doxycycline post-exposure prophylaxis (doxy-PEP). These matched CDC guidance and additionally encouraged shared decision-making between providers and patients with at least 2 sex partners in the last year who were assigned male sex at birth. San Francisco AIDS Foundation’s Magnet Clinic, a large, community-based clinic in San Francisco’s Castro neighborhood, provides doxy-PEP in line with these recommendations. We used Magnet Clinic patient data to define and produce population estimates for a doxy-PEP continuum among patients with indication for doxy-PEP overall and stratified by select demographics. At each stage of the continuum, we assessed whether characteristics were associated with drop-off. Methods: Among patients seen from December 2022-December 2024, we restricted to those with (1) a doxy-PEP indication. We then estimated the proportion who (2) received a doxy-PEP prescription; (3) initiated (i.e. self reported ever taking) doxy-PEP; and (4) adhered to doxy-PEP (i.e. self-reported consistent use within 72 hours after sexual exposures since their last clinic visit). We stratified these analyses by several sociodemographic and health characteristics. We conducted one-tailed tests of equal proportions in each stratified analysis, where the referent was the group most likely to reach a given stage in the continuum conditional on reaching the prior stage. Results: In the study period, 7,436 patients with indication for doxy-PEP were seen at the Magnet Clinic. Among them, 4,369 (60%) were prescribed doxy-PEP. Among those prescribed, 2,651 (61%) reported using it at least once. Among those who used doxy-PEP, 1,627 (61%) reported high adherence at their most recent clinic visit ( Figure ). Among patients with indications, transgender women were more likely to be prescribed doxy-PEP compared with other gender identities. At each stage of the continuum, patients living with HIV had higher drop-off rates compared to HIV-negative patients. Conclusions: Although doxy-PEP is a safe, low-cost biomedical intervention for bacterial sexually transmitted infections, only 36% of Magnet Clinic patients with indication ever used it, and less than 25% were adherent. To maximize the impact

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Conclusions: Among a large clinical cohort of PWH, despite high STI rates, early uptake of DoxyPEP was minimal, yet a majority of PWH were DoxyPEP eligible. While the NNT varied based on the strategy, widespread DoxyPEP uptake could result in significant decreases in STI incidence among PWH. As DoxyPEP use rolls out, greater awareness of its use and prescribing efforts should be emphasized among PWH. High Sustained Effectiveness of Doxycycline PEP for STI Prevention After Clinical Implementation Hyman Scott 1 , Jorge Roman 2 , Matthew A. Spinelli 3 , Jason Bena 2 , Michael P. Barry 2 , Megan J. Heise 3 , Susan Buchbinder 1 1 San Francisco Department of Public Health, San Francisco, CA, USA, 2 San Francisco AIDS Foundation, San Francisco, CA, USA, 3 University of California San Francisco, San Francisco, CA, USA Background: Doxycycline for post-exposure prophylaxis (DPEP) is highly effective for preventing bacterial sexually transmitted infections (STIs) in clinical trials; however recent real-world data suggests lack of effectiveness for gonorrhea. We examined the impact of DPEP on STIs (syphilis, chlamydia, and gonorrhea) in clients at a large sexual health clinic in San Francisco, CA, US. Methods: Starting in 11/30/2022 DPEP was offered to all clients receiving sexual health services. For clients who were prescribed DPEP (Users) for >90 days, we evaluated up to 5 quarters before and after the initial DPEP prescription through 09/24/2024. For clients who were never prescribed DPEP (Non-DPEP users), we evaluated up to 5 quarters before and after 4/2023 – the midpoint (median) quarter for the DPEP initiations across the evaluation period. We fit an interrupted time series (ITS) analysis in which STI rates, overall and by individual STI, were predicted by a three-way interaction between DPEP use, time (in quarters), and DPEP initiation (pre-post DPEP prescription for the DPEP Users, and pre-post median time for the non-DPEP users). Results: Overall, 4,149 clients (2,419 DPEP users and 1,730 non-DPEP users) were included in the analyses with an average of 3.13 (SD=1.70) quarters of follow-up. The median age range was 30-39 years and most (89%) were cisgender men. Race/ethnicity included 33% White, 24% Hispanic/Latinx, 17% Asian, 13% multiracial, and 4% Black. Almost all (98.7%) were also prescribed HIV pre exposure prophylaxis. Before initiating DPEP, the DPEP users had significantly higher risk of an STI than non-DPEP users [Odds Ratio (OR)=5.33, 95% Confidence Interval (CI) 4.11-6.90, p<.001); however, after initiation STI rates were similar (OR=1.21, 95%CI 0.86-1.68, p=.280). In a pre-post analysis among DPEP users, STI incidence declined significantly overall (OR=0.28, 95%CI 0.24-0.35, p<.001) and for each STI: chlamydia (OR=0.05; 95%CI 0.11-0.20, p<.001), gonorrhea (OR=0.45; 95%CI 0.39-0.53, p<.001), and syphilis (OR=0.16; 95%CI 0.12-0.21,

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CROI 2025