CROI 2025 Abstract eBook

Abstract eBook

Oral Abstracts

exists. Ultimately, in countries with high HIV/HPV coinfection rates, integrating these services could minimise disparities in the global HPV cancer burden. Impact of Urine TFV Testing on PrEP Adherence in South African Pregnant and Postpartum Women: An RCT Dvora L. Joseph Davey 1 , Kalisha Bheemraj 2 , Rufaro Mvududu 2 , Sumaya Dadan 2 , Kathryn L. Dovel 1 , Susan Cleary 2 , Monica Gandhi 3 , Thomas Coates 1 , Landon Myer 2 1 University of California Los Angeles, Los Angeles, CA, USA, 2 University of Cape Town, Cape Town, South Africa, 3 University of California San Francisco, San Francisco, CA, USA Background: Non-adherence to oral TDF/FTC PrEP reduces efficacy for HIV prevention, including in pregnant and postpartum women (PPW). Urine tenofovir (TFV) testing detects dosing in past 72 hours in people taking oral PrEP, but there are few insights into whether providing PPW with feedback on urine TFV test results can support PrEP adherence. We examined this as the primary outcome of Step 1 of the Stepped Care to Optimize PrEP Effectiveness in PPW trial (NCT05322629). Methods: We enrolled pregnant women attending primary care antenatal services in Cape Town without HIV who were >15 years old, >20 weeks’ gestation, and initiating or taking PrEP in pregnancy. We block randomized women 1:1 to the intervention (Int; biofeedback counseling based on urine TFV test result) vs. standard of care control (SOC; PrEP counseling without biofeedback; urine collected and TFV testing performed without the participant). PrEP was delivered to all women through standard public health services. The primary outcome was the impact of the urine TFV biofeedback intervention on objective PrEP adherence measured at 6m (based on urine TFV test results in both arms). Primary analyses were via intention to treat and assumed that women who did not attend the 6m study follow-up visit were non-adherent to PrEP. Results are presented at risk ratios (RR) with 95% Confidence Intervals (CI). Results: Among 750 HIV- women on or initiating PrEP in pregnancy randomised (375 Int; 375 SOC), median age was 26 years (IQR:22-32); median gestational age was 29 weeks (IQR:23-35); 38% were married or cohabiting. Overall, 54% of women attended the 6m primary outcome visit (Int=58%; SOC=51%) of whom 66% self-reported PrEP in the past week (Int=68%, SOC=64%). For the primary outcome, 32% of Int participants had urine TFV+ (n=120 of 372) vs. 25% in SOC (n=91 of 365) (RR=1.29; 95% CI=1.03-1.63; Table ). Findings persisted after adjustment for socio-demographic and HIV risk factors and were consistent across subgroups of PPW age, timing of enrollment and follow-up, and HIV risk markers. Conclusions: In this setting a large proportion of women initiating PrEP in pregnancy do not persist through 6m; however, biofeedback using urine TFV testing was associated with small but significant increases in PrEP adherence. These findings point to the urgent need for long-acting PrEP modalities for PPW,

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Oral Abstracts

of doxy-PEP, clinicians should encourage increased uptake and adherence among those with indication. Global Modelling Analysis: Impact of Improved HPV Vaccination on Non-Cervical Cancers in PLWHIV Namwa Wongkalasin 1 , Victoria Pilkington 1 , Jacob Levi 2 , Toby Pepperrell 3 , Anna Garratt 4 , Andrew Hill 5 1 Imperial College London, London, UK, 2 Metavirology, Ltd, London, UK, 3 University of Edinburgh, Edinburgh, UK, 4 University of Cardiff, Cardiff, UK, 5 University of Liverpool, Liverpool, UK Background: HIV infection significantly increases carcinogenesis following HPV infection. The impact of this relationship on the cervical cancer burden is well documented. Less is known on HPV non-cervical cancers including anal, oropharyngeal, vaginal, vulvar and penile cancers. The World Health Organisation (WHO) aims to vaccinate 90% of girls under 15 against HPV, yet global vaccine coverage is low at 21% for girls and 7% for boys. Coverage is especially low in countries with a high HIV prevalence. We aimed to evaluate the burden of HPV non-cervical cancers in people living with HIV (PLWHIV) and model the potential impact of improved gender-neutral HPV vaccine coverage worldwide. Methods: We collected epidemiological data on cancer incidence in 185 countries from the GLOBOCAN 2022 database. HIV prevalence was collected from UNAIDS 2022, which analyses country-specific rates using the SPECTRUM model. The number of cancer cases was combined with relative risks of developing each cancer and HIV prevalence data to generate a population attributable fraction, which estimates the number of cancers ‘attributable’ to HIV. Lastly, we modelled the impact of improved vaccine coverage using point vaccine efficacy estimates and country-specific HPV vaccine coverage levels from the WHO. Results: Globally, this burden exhibited significant geographical variation; 29% of all HPV-related non-cervical cancer cases in Africa may be HIV-attributable, compared to 5% worldwide. For anal cancer, an estimated 35,719 cases occurred worldwide in 2022 and 12.4% of these may have been attributable to HIV. This attributable fraction ranged from 1.5% in Southeast Asia, to 10.6% in the Americas, to more than 41.8% in Africa. We show that out of the ten countries with the highest number of HIV-attributable cancers, only two had vaccine coverage rates over 50%. Globally, our model shows that if gender-neutral vaccine coverage increases to the WHO’s 90% target, we could prevent 6854 cancer cases in PLWHIV; reflecting more than double the number currently prevented. Conclusions: This analysis adds to the consensus that PLWHIV warrant special consideration in HPV prevention. More research is needed on vaccine efficacy

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and among women who use oral TDF/FTC, the potential impact of biofeedback interventions to enhance adherence.

in PLWHIV to inform future analyses. HPV vaccination is particularly important in Southern Africa where a large concurrent burden of HIV-attributable cancers

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CROI 2025