CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

at 12 months as determined by hair levels. The real-time urine TFV assay may have a role in improving long-term PrEP adherence.

prevention counseling, PrEP dispensation, and adherence counseling. Midway through the study, the POC TFV test (Abbott Diagnostics®) was introduced as part of routine study procedures alongside self-reported data captured by interviewer-administered questionnaires and dried blood spots (DBS) for TFV diphosphate (DP) quantification. We defined accurate self-reported PrEP use if participants reported high PrEP adherence and had detectable levels of TFV-DP in DBS. We examined changes in self-reported adherence, sexual behavior, and accuracy of self-reported PrEP adherence before and after the introduction of the POC TFV test using a generalized estimated equation logistic regression model with independence correlation structure. Results: A total of 146 women receiving PrEP refills had ≥1 visit with a POC TFV test administered before study exit. The median age was 19 years (interquartile range [IQR]: 18-21) and the majority (76%) reported having condomless sex within the last three months at baseline. Comparing self-reported adherence before and after the introduction of the POC TFV test, participants more frequently reported low PrEP adherence (OR: 2.96, 95% confidence interval [CI]: 1.89-4.67, p=0.001) and condomless sex (OR: 1.47, 95% CI: 1.04-2.06, p=0.03) during the 146 visits with the test compared to the 146 visits without the test. Accuracy of self-reported PrEP adherence assessed by DBS TFV-DP levels was greater when the test was used (61% versus 24%, OR: 4.86, 95% CI: 2.85-8.30, p<0.001). Conclusion: We saw greater report of condomless sex and low PrEP adherence, behaviors that are socially less desirable, when the POC TFV test was used indicating that the test could play a vital role facilitating honest conversations between clients and providers. The POC TFV test could be evaluated for real time adherence monitoring in public sector PrEP programs. 1113 PrEP Counseling Based on a Tenofovir Urine Assay Decreases Overall Non Adherence Among Kenyan Women Monica Gandhi 1 , David V. Glidden 1 , Matthew A. Spinelli 1 , Charlene Biwott 2 , Gakuo Maina 2 , Irene Njeru 3 , Catherine Kiptinness 3 , Phelix Okello 2 , Purba Chatterjee 1 , Guohong Wang 4 , Vallery Ogello 2 , Hideaki Okochi 1 , Deepalika Chakravarty 1 , Nelly R. Mugo 3 , Kenneth Ngure 5 1 University of California San Francisco, San Francisco, CA, USA, 2 Kenya Medical Research Institute, Kilifi, Kenya, 3 Kenya Medical Research Institute, Nairobi, Kenya, 4 Abbott Labs, Abbott Park, IL, USA, 5 Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya Background: Adherence to oral pre-exposure prophylaxis (PrEP) with tenofovir (TFV)-based PrEP among women in Africa in non-serodiscordant partnerships can be low based on clinical trial and real-world data. A point-of-care (POC) urine assay to objectively assess TFV in urine was recently developed by our group and POC urine monitoring of adherence-informed counseling (PUMA) increases virologic suppression rates among people with HIV on antiretroviral therapy. We performed a pilot trial examining the impact of PUMA on long-term PrEP adherence among HIV-negative women in Kenya. Methods: A pilot study randomized 100 women in non-serodiscordant partnerships in Thika, Kenya to standard-of-care (SOC) adherence counseling every 3 months for 12 months versus PUMA with visualization of the POC test by providers and participants. Urine tests were collected for 12-month analysis in the SOC arm, without providing results to participants or staff. Hair samples were collected at month 12 to assess the primary outcome of TFV levels in hair as a long-term metric of adherence in both arms. TFV levels in hair were measured by the UCSF Hair Analytical Laboratory using validated methods; TFV levels below the limit of quantification (BLQ) in hair, specifically <0.002 nanograms/ milligrams, defined long-term non-adherence. Results: The trial enrolled 49 women in the PUMA arm and 51 women in the SOC arm with counseling performed every 3 months. Retention in the study was 86% in both arms. Hair was collected and tested from 42 participants in the PUMA arm at month 12; hair was collected from 43 participants and testing completed for 41 of those samples in the SOC arm. The percent of hair samples at 12 months with TFV levels BLQ in the SOC arm was 37% versus 21% in the PUMA arm. The relative odds of long-term non-adherence in the SOC arm compared to the PUMA arm was 3.53 (95% confidence interval 1.03, 12.03, p value 0.04). Knowledge that the urine assay was being performed in the PUMA arm seemed to decrease overall non-adherence as compared to the control arm, even when the urine assay showed no TFV (Figure). One seroconversion occurred over the 12-month study in the SOC arm. Conclusion: Scalable low-cost adherence interventions to increase pill-taking with oral PrEP are needed. PrEP counseling informed by a POC urine TFV test among at-risk Kenyan women on PrEP decreased overall non-adherence to PrEP

1114 Point-of-Care Urine Tenofovir Test Predicts Future PrEP Discontinuation Among Young PrEP Users Matthew A Spinelli 1 , Rikki Montoya 2 , Carlos Morerira 1 , Karen Kuncze 1 , Kevin Sassaman 1 , David V. Glidden 1 , K Rivet Amico 3 , Emily Arnold 1 , Susan P. Buchbinder 4 , Leah Davis Ewart 5 , Adam Carrico 5 , Guohong Wang 6 , Hideaki Okochi 1 , Hyman Scott 2 , Monica Gandhi 1 1 University of California San Francisco, San Francisco, CA, USA, 2 San Francisco AIDS Foundation, San Francisco, CA, USA, 3 University of Michigan, Ann Arbor, MI, USA, 4 San Francisco Department of Public Health, San Francisco, CA, USA, 5 Florida International University, Miami, FL, USA, 6 Abbott Labs, Abbott Park, IL, USA Background: Young men who have sex with men (MSM) and transgender women (TGW) have both disproportionately high HIV incidence and greater challenges with PrEP persistence. POC urine tenofovir (TFV) testing permits real time objective monitoring for non-adherence within clinical settings at a low cost. We performed urine point-of-care (POC) testing among young PrEP users (age<30) at a high-volume PrEP clinic to examine: 1) the relationship between low PrEP adherence and future PrEP discontinuation, and (2) the accuracy of POC testing vs. liquid chromatography tandem mass spectrometry (LC-MS/MS). Methods: Participants (age<30) were recruited at the time of a daily PrEP (F/ TDF or F/TAF) visit and asked to provide a urine sample and complete a survey. Adjusted logistic regression models analyzed the relationship between the primary predictor of urine POC lateral flow assay results (cut-off of 1,500 ng/mL) and the primary outcome of PrEP discontinuation, defined as no PrEP follow-up within ≥120 days of observation, given that only 90-day prescriptions were provided. Results: Overall, the participants (n=100) had a median age of 27 (IQR 21-29) years; 12% identified as gender queer, 2% as TGW; 23% Hispanic, 20% Asian, 10% Black, 2% Native American, 2% Pacific Islander; 33% used F/TAF; 95% had at least 2 partners of unknown status. At the index PrEP visit (6/2021-5/2023), 19% had low urine TFV, and 21% discontinued PrEP without follow-up within 120 days. A low urine TFV predicted future PrEP discontinuation (AOR 6.1; 95% CI: 1.4-11; p=0.005) and was 71% sensitive and 90% specific for future discontinuation. All participants with low TFV at the index visit reported condomless anal sex with ≥2 partners of unknown status. Self-reported low adherence (<4 pills weekly) was not associated with PrEP discontinuation (p=0.18); and was only 43% sensitive and 84% specific in predicting low TFV levels. When compared to LC-MS/MS testing, POC testing was 98% sensitive/100% specific. Most (98%) wanted to be able to use the urine test on their own, 94% if it could only be administered by a clinician. Conclusion: In a diverse sample of young MSM and transgender women using oral F/TDF or F/TAF PrEP, POC urine TFV testing predicted future PrEP discontinuation more accurately than self-report and was highly accurate when compared to LC/MS-MS. Urine POC testing can be a powerful tool for targeting PrEP adherence interventions towards those most likely to discontinue PrEP in the future.

Poster Abstracts

CROI 2024 361