Coverage of Sex Acts by Event-Driven Pre-exposure Prophylaxis: A Sub-Study of the ANRS IPERGAY Trial

Evaluation of pharmacokinetics of Tenofovir Alafenamide (TAF) and Tenofovir Disoproxil (TDF) in pregnant and postpartum women in South Africa: PrEP-PP PK study

BACKGROUND

There are few data on tenofovir-diphosphate (TFV-DP) concentrations in pregnant and postpartum women on Tenofovir Disoproxil Fumarate-Emtricitabine (TDF-FTC) or Tenofovir Alafenamide-Emtricitabine (TAF-FTC).

METHODS

Eligible pregnant women were randomized to TDF-FTC or TAF-FTC and followed for 16 weeks (8-weeks pregnant, 8-weeks postpartum) with weekly collection of dried blood spot (DBS) and 4-weekly peripheral blood mononuclear cells (PBMC). PrEP dosing was observed daily via asynchronous videos sent via cell phone. We report geometric means (GM) and their ratios (GMR) with 95% confidence intervals (CIs) for TFV-DP in PBMC and DBS from pregnancy and postpartum.

RESULTS

We enrolled N = 39 participants (n = 19 TDF-FTC, n = 20 TAF-FTC): median age was 28 years (IQR:25-34); median gestational age was 24-weeks (IQR:21-28). For TDF-FTC, TFV-DP DBS concentrations at 8-weeks did not differ significantly between pregnancy (GM: 675; 95%CI:537-849) and postpartum (GM: 583; 95%CI:471-722; GMR-TDF = 1.16; 95%CI:0.74-1.80). For TAF-FTC, TFV-DP DBS concentrations at 8-weeks were 44% higher in postpartum (GM: 1199; 95%CI:929-1549) versus pregnancy (GM: 832; 95%CI:751-922; GMR-TAF = 1.44; 95% CI: 1.01-2.06). In PBMC analysis of TDF-FTC, 8-week median TFV-DP (pmol/10^6 cell) was 71 (IQR 44-112) in pregnancy and 73 (IQR 50-102) in postpartum (GMR = 1.04; 95%CI:0.44-2.44). In TAF-FTC, median PBMC at 8-weeks was 580 (IQR:341-985) in pregnancy and 666 (IQR:396-1123) in postpartum (GMR = 1.15; 95%CI:0.30-2.49).

CONCLUSION

TFV-DP concentrations were overall lower during pregnancy than postpartum for TAF-FTC. We found high concentrations of TFV-DP in PBMC in pregnancy and postpartum on TAF-FTC, suggesting PrEP efficacy is maintained. Efficacy and safety studies are warranted to evaluate TAF-FTC for PrEP in pregnant and postpartum women.

Prediction of Sex and the Potential Use of On-Demand PrEP Among Young Men Who Have Sex With Men in the United States

BACKGROUND

On-demand dosing of preexposure prophylaxis (PrEP) requires accurate prediction of sex; however, prediction abilities among young men who have sex with men (YMSM) have not been characterized.

SETTING

A nationally recruited prospective cohort of YMSM ages 16-24 years.

METHODS

We followed 120 YMSM for 8 weeks using digital daily surveys (DDSs) to measure engagement in and prediction of anal sex over 24 hours, along with condom use and other encounter-level circumstances. Our main outcome, an "unpredicted spontaneous encounter," was defined as an anal sex encounter that occurred without sufficient prior knowledge to (hypothetically) enable protective on-demand PrEP use according to dosing guidelines. We operationalized this outcome as an anal sex encounter for which a participant indicated: (1) on the prior day's DDS that there was a low likelihood of sex occurring in the subsequent 24 hours (unpredicted) and (2) on the current day's DDS that he knew ≤2 hours in advance that the encounter would occur (spontaneous).

RESULTS

Approximately one-third of all anal sex encounters during the study period were unpredicted and spontaneous and would not have been protected (hypothetically) by on-demand dosing. More than two-thirds of participants experienced such an encounter and almost three-quarters of all acts were condomless.

CONCLUSIONS

On-demand PrEP to prevent HIV acquisition may be challenging for many YMSM. Clinical and public health approaches that account for patients' predictive abilities alongside their dosing preferences may help to optimize selection of and adherence to PrEP dosing strategies.

Can We Predict Incorrect PrEP Use in High HIV Risk Situations Among Men Who Have Sex With Men? An Analysis of Be-PrEP-ared, the Belgian PrEP Demonstration Study

BACKGROUND

Pre-exposure prophylaxis (PrEP) efficacy for HIV prevention is highly correlated with the degree of adherence. The objective of this analysis was to identify PrEP users who did not correctly take their dose in high HIV exposure situations and to explore potential predictors of this behavior.

METHODS

Study participants completed a personal Web-based diary during their entire follow-up, providing daily information on pill intake and sexual activity. They also completed a sociobehavioral questionnaire. The association between the number of unprotected high HIV exposure sex days (as a measure for suboptimal adherence) and potential predicting factors was examined using a logistic regression, followed by a negative binomial regression model. We also constructed a risk index score for predicting poor adherence.

RESULTS

A total of 40.8% of participants did not correctly use PrEP in at least one situation of high HIV exposure during follow-up. Not having a HIV-negative steady partner, reporting more than 10 occasional or more than 10 anonymous partners, using chemsex drugs, receiving money for sex, and a history of more than one sexually transmitted infection were significantly associated with unprotected high HIV exposure sex. The risk index score yielded a poor discriminative power (area under the curve 0.62 and 0.64).

CONCLUSIONS

We observed a high proportion of suboptimal adherence. Even if none of the participants acquired HIV during the study, tailored adherence support is needed to specific men who have sex with men such as those taking chemsex drugs and those engaging in paid sex.

Estimated pill intake with on-demand PrEP with oral TDF/FTC using TFV-DP concentration in dried blood spots in the ANRS IPERGAY trial

BACKGROUND

Tenofovir diphosphate (TFV-DP) concentration in dried blood spots (DBSs) is a reliable pharmacokinetics biomarker of adherence to tenofovir disoproxil fumarate (TDF). We aimed to use DBSs to estimate pill intake among participants using on-demand pre-exposure prophylaxis (PrEP) and to identify predictive factors associated with higher TFV-DP concentrations.

METHODS

DBSs were collected at the last study visit of the open-label phase of the ANRS IPERGAY study, assessing on-demand oral TDF/emtricitabine for PrEP among MSM and transgender female participants. We quantified TFV-DP in DBSs centrally. We assessed correlation between pill count and TFV-DP concentration by Spearman correlation and explored associations between participant demographics, sexual behaviour and PrEP use during sexual intercourse (SI) with TFV-DP concentrations by univariate and multivariate logistic regression models.

RESULTS

The median age of the 245 participants included in this study was 40 years, with a median body weight of 73 kg. Median (IQR) TFV-DP concentration reached 517 (128-868) fmol/punch, corresponding to an estimated intake of 8-12 tablets per month (2-3 doses per week). Only 39% of participants had a TFV-DP concentration above 700 fmol/punch. TFV-DP concentrations were moderately correlated with pill count (r: 0.59; P < 0.001). In multivariate analysis, only systematic use of PrEP during SI and more frequent episodes of SI in the past 4 weeks were significantly associated with higher TFV-DP levels [OR (95% CI): 11.30 (3.62-35.33) and 1.46 (1.19-1.79), respectively; P < 0.001].

CONCLUSIONS

Among participants using on-demand PrEP, estimated pill intake reached 8-12 tablets per month and was correlated with frequency and systematic use of PrEP for SI.

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

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 three-month 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.

Imperfect adherence in real life: a prevention-effective perspective on adherence to daily and event-driven HIV pre-exposure prophylaxis among men who have sex with men - a prospective cohort study in Taiwan

INTRODUCTION

Both daily and event-driven (ED) pre-exposure prophylaxis (PrEP) have been demonstrated to be highly effective among men who have sex with men (MSM). Prevention-effective adherence proposes that PrEP adherence should be aligned with the risk of HIV, which could be applied to both daily and ED PrEP adherence measurement. The objective of this study was to describe the relationship between the use of PrEP and sex events among the MSM PrEP users and identify factors associated with adherence among daily and ED MSM PrEP users.

METHODS

A multicentre, observational, prospective cohort study was conducted at three hospital-based clinics in three urban cities of Taiwan from January 2018 to December 2019. MSM ages 18 years or older - at high risk of HIV acquisition and taking PrEP during the study period - were included in the analysis. MSM PrEP users were allowed to choose between daily and ED PrEP based on their preference. Data on sociodemographic characteristics, mental health, sexual behaviours, substance use and PrEP-taking behaviours were collected at each visit.

RESULTS

A total of 374 MSM were included in the analysis with 1,054 visits. More than half (56%) of the PrEP users chose ED at the baseline and 150 regimen switches were reported by 21% of the participants. There was only one seroconversion documented during the study period. Most (84.2%) of the MSM PrEP users were able to adhere to PrEP during the most recent anal intercourse in the past one month. Among ED PrEP users with suboptimal adherence, the majority (81.9%) missed the pre-coital dose. In the multivariable analysis, we found that participants who switched from daily to an ED dosing regimen were associated with poorer adherence to PrEP.

CONCLUSIONS

A high level of PrEP adherence was observed among the majority of MSM in a real-world setting. On the other hand, Taiwanese MSM switching from daily to ED dosing regimens were less likely to adhere to PrEP, suggesting that novel approaches focusing on a dosing switch would be necessary for MSM to improve their adherence to PrEP.

A Review of HIV Pre-exposure Prophylaxis Streamlining Strategies

PURPOSE OF REVIEW

Standard care for HIV pre-exposure prophylaxis (PrEP) in the USA creates substantial burdens for patients, clinicians, and the healthcare system; to optimize uptake, there is a need for innovative strategies to streamline its provision.

RECENT FINDINGS

Our review, structured by the expanded chronic care model, identified eleven promising strategies to streamline PrEP care. Approaches ranged widely in mechanism of action. Using text messages to support care was the only strategy with clinical trial evidence supporting its use. Other modalities such as patient navigation, telemedicine PrEP models, alternate dosing availability, same-day prescription, and provider training have promising pilot or associational data and seem likely to lower barriers to entering into or remaining in care. Many of the strategies have established success in related domains such as HIV care, meriting consideration in evaluating their use for PrEP. Making PrEP care less burdensome will be an important part of bringing it to scale. Text message interventions have proven efficacy and merit broad adoption. Encouraging preliminary evidence for other strategies indicates the importance of building a stronger evidence base to clarify the effect of each strategy. Ongoing development of an evidence base should not delay the use of these promising strategies; instead, it calls for careful consideration for how each program may best match its environment to facilitate PrEP prescribing and use.