Adherence to event‐driven HIV PrEP among men who have sex with men in Amsterdam, the Netherlands: analysis based on online diary data, 3‐monthly questionnaires and intracellular TFV‐DP

Abstract

Introduction: Event-driven pre-exposure prophylaxis (edPrEP) with oral tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) is highly effective for preventing HIV acquisition in men who have sex with men (MSM) and is preferred over daily PrEP by some MSM. However, it is largely unknown how well MSM adhere to edPrEP. We then aimed to assess PrEP protection during CAS among MSM using edPrEP and participating in the Amsterdam PrEP demonstration project (AMPrEP). Methods: We analysed data from participants enrolled in AMPrEP who were taking edPrEP. We measured adherence through (1) a mobile application in which sexual behaviour and PrEP-use were recorded daily, (2) three-monthly self-completed questionnaires and (3) dried blood spot (DBS) samples collected around six, twelve and twenty-four months after PrEP initiation. We assessed the proportion of days with condomless anal sex (CAS) acts that were protected by PrEP, per partner type (i.e. steady partners, known casual partners, unknown casual partners), and the proportion of three-month periods during which PrEP was correctly used. Intracellular TFV-diphosphate (TFV-DP) concentrations were determined from DBS. Good adherence was defined as at least one tablet before and one tablet within 48 hours after a CAS act. Results: Between 11 September 2015 and 6 October 2019, 182 of 376 MSM (48.4%) used edPrEP for at least one threemonth period. Of the 8224 CAS days that were reported in the app during edPrEP-use, we observed good protection for most CAS days involving steady partners (n = 1625/2455, 66.9%), known casual partners (n = 3216/3472, 92.6%) and unknown casual partners (n = 2074/2297, 90.3%). Men reported consistently correct PrEP-use in 851 (81.4%) of the 1046 three-month periods of edPrEP-use. The median TFV-DP concentration was 591 fmol/sample (interquartile range = 270 to 896). Conclusions: Adherence to edPrEP was high as determined from the online app and questionnaire. DBS measurements were consistent with two to three tablets per week on average.

The Influencing Factors of HIV-Preventive Behavior Based on Health Belief Model among HIV-Negative MSMs in Western China: A Structural Equation Modeling Analysis

“…Highly effective protection against HIV infections in MSMs has been affirmed in the pre-exposure prophylaxis (PrEP) trials [ 8 , 9 , 10 ]. However, the effectiveness of PrEP largely depends on medication adherence according to the ninth International AIDS Society conference (WHO, 2017) on HIV science in 2017 and our previous research [ 11 , 12 , 13 ].…”

Offering a choice of daily and event-driven preexposure prophylaxis for men who have sex with men in the Netherlands: a cost-effectiveness analysis

“…Nevertheless, data from AMPrEP show that precisely the ability to predict or plan sex contacts was one of the main reasons for choosing event-driven PrEP [4]. Also, based on data on CAI events and PrEP medication use as reported daily in the mobile application used by AMPrEP participants, the 3-monthly questionnaires, and the measured intracellular tenofovir levels, we established high levels of adherence among event-driven PrEP users [33]. In addition, HIV incidence was very low among both daily (0.76 infections per 100 person-years, 95% confidence interval [CI] 0.19-3.03) and event-driven (0 infections per 100 person-years, 95% CI 0-3.96) PrEP users in AMPrEP [6], suggesting similar good adherence in both groups.…”

HIV-1-infection in a man who has sex with men despite self-reported excellent adherence to pre-exposure prophylaxis, the Netherlands, August 2021: be alert to emtricitabine/tenofovir-resistant strain transmission

“…An objective method to assess adherence in daily PrEP is measuring intracellular tenofovir levels in dried blood spots [ 14 ]. However, this is not applicable to event-driven PrEP use as the levels will not provide information on whether the PrEP tablets were correctly used before and after sexual contact [ 15 ].…”