Current concepts for PrEP adherence in the PrEP revolution: from clinical trials to routine practice

Curlin M, Holtz TH, Mannheimer S, Marzinke MA, Amico KR, Liu A, Piwowar-Manning E, Eshleman SH, Dye BJ, Gandhi M, Grant RM. Short- and Long-Term Pharmacologic Measures of HIV Pre-exposure Prophylaxis Use Among High-Risk Men Who Have Sex With Men in HPTN 067/ADAPT

BACKGROUND

The effectiveness of oral emtricitabine (FTC)/tenofovir (TFV) disoproxil fumarate-based HIV pre-exposure prophylaxis (PrEP) depends on adherence. Pharmacologic measures help interpret patterns and predictors of PrEP adherence.

SETTING

We analyzed data from the subsample of men who have sex with men enrolled in HPTN 067/ADAPT in Bangkok, Thailand, and Harlem, NY, U.S.

METHODS

After a 5-week directly observed therapy period, participants were randomized to daily, time-driven, or event-driven PrEP. Follow-up occurred at weeks 4, 12, and 24 after randomization. Plasma and hair FTC/TFV levels indicated short- and long-term PrEP use, respectively. Electronic pill bottle data (Wisepill) were collected weekly. Pearson correlation coefficients between PrEP use measures were calculated; linear mixed models assessed predictors of plasma and hair drug concentrations.

RESULTS

Among 350 participants (median age: 31 years, interquartile range: 25-38), 49.7% were from Harlem, half had less than college education, and 21% reported heavy alcohol use. In multivariable models, being enrolled in Harlem, being in non-daily arms, and having less than college education were associated with lower hair FTC/TFV concentrations; heavy alcohol use was associated with higher concentrations. Similar results were found for plasma concentrations by site and arm, but older age and greater number of sex partners were associated with higher concentrations. Hair and plasma FTC/TFV concentrations were moderately correlated with Wisepill data (r ≥ 0.29) across visits.

CONCLUSIONS

In HPTN067, plasma, hair, and Wisepill data correlated with one another and served as complementary adherence measures. Site, arm, education, age, alcohol, and sexual behavior influenced patterns of adherence.

Creation of a long-acting rilpivirine prodrug nanoformulation

Antiretroviral therapy requires lifelong daily dosing to attain viral suppression, restore immune function, and improve quality of life. As a treatment alternative, long-acting (LA) antiretrovirals can sustain therapeutic drug concentrations in blood for prolonged time periods. The success of recent clinical trials for LA parenteral cabotegravir and rilpivirine highlight the emergence of these new therapeutic options. Further optimization can improve dosing frequency, lower injection volumes, and facilitate drug-tissue distributions. To this end, we report the synthesis of a library of RPV prodrugs designed to sustain drug plasma concentrations and improved tissue biodistribution. The lead prodrug M3RPV was nanoformulated into the stable LA injectable NM3RPV. NM3RPV treatment led to RPV plasma concentrations above the protein-adjusted 90% inhibitory concentration for 25 weeks with substantial tissue depots after a single intramuscular injection in BALB/cJ mice. NM3RPV elicited 13- and 26-fold increases in the RPV apparent half-life and mean residence time compared to native drug formulation. Taken together, proof-of-concept is provided that nanoformulated RPV prodrugs can extend the apparent drug half-life and improve tissue biodistribution. These results warrant further development for human use.

Performance of HIV pre-exposure prophylaxis indirect adherence measures among men who have sex with men and transgender women: Results from the PrEP Brasil Study

Introduction

Efficacy of daily emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) for PrEP is strongly dependent on the adherence. We examined the concordance between indirect adherence measures and protective drug levels among participants retained through 48 weeks in the PrEP Brasil Study.

Methods

PrEP Brasil was a prospective, multicenter, open-label demonstration project evaluating PrEP provision for men who have sex with men (MSM) and transgender women (TGW) at higher risk for HIV infection within the setting of Brazilian Public Health System. Three indirect adherence measures were obtained at week 48: medication possession ratio (MPR), pill count and self-report (30-days recall). Tenofovir diphosphate (TFV-DP) concentration in Dried Blood Spot (DBS) was measured at week 48. Areas under (AUC) the receiver operating characteristics (ROC) curve were used to evaluate the concordance between achieving protective drug levels (TFV-DP≥700fmol/punch) and the indirect adherence measures. Youden’s index and distance to corner were used to determine the optimal cutoff points for each indirect adherence measure. We calculated sensitivity, specificity, negative (NPV) and positive (PPV) predictive values for the found cutoff points. Finally, Delong test was used to compare AUCs.

Results and discussion

From April, 2014 to July, 2016, 450 participants initiated PrEP, 375(83.3%) were retained through 48 weeks. Of these, 74% (277/375) had TFV-DP ≥700fmol/punch. All adherence measures discriminated between participants with and without protective drug levels (AUC>0.5). High indirect adherence measure was predictive of protective drug levels (PPV>0.8) while low indirect adherence measure was not predictive of lack of protective drug levels (NPV<0.5). No significant differences were found between the adherence methods (p = 0.44).

Conclusions

Low-burden measurements such as MPR and self-report can be used to predict PrEP adherence in a public health context in Brazil for MSM and TGW retained through 48 weeks.

Clinical Trial Number: NCT01989611.

Global implementation of PrEP for HIV prevention: setting expectations for impact

INTRODUCTION

Questions remain whether HIV pre-exposure prophylaxis (PrEP) can be translated into a successful public health intervention, leading to a decrease in population-level HIV incidence. We use examples from HIV treatment and contraceptives to discuss expectations for PrEP uptake, adherence, and persistence and their combined impact on the epidemic.

DISCUSSION

Targets for PrEP uptake must be based on the local HIV epidemic and will depend on appropriate estimates of the key populations at risk for HIV. However, there is evidence that targets, once established, can successfully be met and that uptake may increase with awareness. Messaging around adherence should include that daily adherence is the goal (except for those MSM for whom event-driven dosing is a good fit), but perfect adherence should not be a barrier. Ideally, clients persist on PrEP for as long as they are at risk for HIV. While PrEP will be most effective when coverage is focused on high-risk populations, normalizing rather than stigmatizing PrEP will be highly beneficial.

CONCLUSIONS

While many challenges to PrEP implementation exist, we focused on the three key steps of uptake, adherence and persistence as measurable processes that can lead to improved coverage and decreased HIV incidence.

Long-term retention in pre-exposure prophylaxis care among men who have sex with men and transgender women in the United States

INTRODUCTION

Retention in HIV pre-exposure prophylaxis (PrEP) care in real-world settings, outside of controlled trials or demonstration projects, remains poorly understood.

METHODS

We evaluated retention in PrEP care outcomes among men who have sex with men (MSM) and transgender women prescribed PrEP through March 2017 at three clinical sites in the United States (US): Jackson, Mississippi; Providence, Rhode Island; and St. Louis, Missouri. We determined retention rates by attendance of clinical visits every three months, per US Centers for Disease Control and Prevention (CDC) guidelines, as well as by the timing of patients' actual clinical visits. Multivariable analyses examined demographic and behavioural factors associated with retention.

RESULTS

From 2013 to 2015, 282 MSM and transgender women were prescribed PrEP; 82% attended a follow-up visit. Based on CDC recommendations, 56% of patients were retained in PrEP care at the first follow-up visit, having attended a visit three months after initiation. However, 76% had a follow-up visit within eight months. Thirty-percent were retained at 12 months by CDC criteria, but 62% were retained when using a 16-month endpoint. Self-reported adherence was strongly correlated with retention. In multivariable analyses, younger age was associated with decreased odds of retention at initial follow-up, and completing college was associated with increased odds of retention at 16 months. Eight participants were newly diagnosed with HIV; six were African American, and seven were under 30 years of age.

CONCLUSIONS

Measuring retention in PrEP care using three-month follow-up intervals may underestimate true retention. Nevertheless, retention in PrEP care is suboptimal in real-world settings and should be the focus of future interventions.

Long-term retention in pre-exposure prophylaxis care among men who have sex with men and transgender women in the United States

INTRODUCTION

Retention in HIV pre-exposure prophylaxis (PrEP) care in real-world settings, outside of controlled trials or demonstration projects, remains poorly understood.

METHODS

We evaluated retention in PrEP care outcomes among men who have sex with men (MSM) and transgender women prescribed PrEP through March 2017 at three clinical sites in the United States (US): Jackson, Mississippi; Providence, Rhode Island; and St. Louis, Missouri. We determined retention rates by attendance of clinical visits every three months, per US Centers for Disease Control and Prevention (CDC) guidelines, as well as by the timing of patients' actual clinical visits. Multivariable analyses examined demographic and behavioural factors associated with retention.

RESULTS

From 2013 to 2015, 282 MSM and transgender women were prescribed PrEP; 82% attended a follow-up visit. Based on CDC recommendations, 56% of patients were retained in PrEP care at the first follow-up visit, having attended a visit three months after initiation. However, 76% had a follow-up visit within eight months. Thirty-percent were retained at 12 months by CDC criteria, but 62% were retained when using a 16-month endpoint. Self-reported adherence was strongly correlated with retention. In multivariable analyses, younger age was associated with decreased odds of retention at initial follow-up, and completing college was associated with increased odds of retention at 16 months. Eight participants were newly diagnosed with HIV; six were African American, and seven were under 30 years of age.

CONCLUSIONS

Measuring retention in PrEP care using three-month follow-up intervals may underestimate true retention. Nevertheless, retention in PrEP care is suboptimal in real-world settings and should be the focus of future interventions.

Pre-Exposure Prophylaxis (PrEP) in Men Who have Sex with Men in Bouaké, Côte d’Ivoire: A Qualitative Evaluation of Acceptability

Background:

HIV remains an important public health issue throughout the world. In Côte d’Ivoire, a high burden of HIV is observed in men who have sex with men (MSM).

Objective:

We assessed the acceptability of Pre-Exposure Prophylaxis (PrEP) among men who have sex with men (MSM) in Bouaké, Côte d’Ivoire.

Methods:

We conducted and analysed four focus groups with 31 HIV-negative MSM and eight in-depth individual interviews with participants recruited from the focus groups.

Results:

Four MSM (13%) were aware of PrEP before participating in the study. All the participants were interested in taking PrEP if available: 19 (61.3%) would prefer the daily regimen and 12 (38.7%) would opt for the on-demand regimen. Many advantages of PrEP were mentioned: protection in case of a condom break, protection in case of high-risk sexual behaviour, self-reliance, decreasing HIV fear and ease of use. Barriers to the use of PrEP included: it does not protect against other Sexually Transmitted Tnfections (STIs), taking a pill regularly is necessary, the size of the pill, possibility of side effects, the cost and accessibility. Six participants (19.3%) admitted that they would use condoms less if they take PrEP.

Conclusion:

Findings indicate that PrEP is acceptable within the MSM community. Implementation should be done rapidly, and PrEP should be part of a global prevention program which includes counselling, STI screening and promotion of safe sex practices. Health authorities should consider PrEP for all high-risk groups to avoid worsening stigmatization by targeting MSM only.

Assessment of Demographic and Socio-Behavioral Factors on Adherence to HIV Pre-Exposure Prophylaxis Using a Markov Modeling Approach

Purpose: Adherence is important for the effectiveness of human immunodeficiency virus (HIV) preexposure prophylaxis (PrEP). The objective of the current work is to assess the impact of multiple demographic and socio-behavioral factors on the adherence to tenofovir-based PrEP among HIV serodiscordant couples in East Africa using Markov mixed-effects modeling approach.

Methods: The Partners Demonstration Project was a prospective, open-label, implementation science-driven study of HIV PrEP among heterosexual HIV serodiscordant couples in Kenya and Uganda. The uninfected partner received oral PrEP according to the “bridge to antiretroviral therapy [ART]” strategy (i.e., until the infected partner had been on ART for ≥6 months). Adherence was monitored electronically; demographic and socio-behavioral data were collected during study visits. Analyzed data reflect 12 months of follow-up per participant. A two-state, first-order, discrete time Markov model was developed with longitudinal adherence data characterized by “dose taking (1)” and “dose missing (0).” Covariate effects were linearly added in the logit domain of transition probability parameters (P01 and P10) in the model. The full covariate model was initially developed, followed by backward elimination process to reduce the model. All significant covariates reported by a prior primary statistical analysis of the same data were included in the full covariate model.

Results: The model included data from 920 participants, who were predominantly male (65%). Significant covariates associated with higher adherence were 25 years or older [odds ratio (OR) for P10, 0.61], female sex (OR for P10, 0.67), participant wanting the relationship with the partner to succeed (OR for P10, 0.79; OR for P01, 1.45), and sex with partner either with 100% or <100% condom use compared to those reported no sex (OR for P10, 0.84; OR for P01, 1.21). Significant covariates associated with lower adherence were partner on ART >6 months (OR for P01, 0.86; OR for P10, 1.34), subject in the study for >6 months (OR for P01, 0.8; OR for P10, 1.25), and problematic alcohol use (OR for P01, 0.63; OR for P10, 1.16).

Conclusion: The developed Markov model provides a mechanistic understanding of relationship between demographic, socio-behavioral covariates, and PrEP adherence, by indicating the pattern of adherence influenced by each factor over time. Such data can be used for further intervention development to promote PrEP adherence.

Protocol for a longitudinal study to evaluate the use of tenofovir-based PrEP for safer conception and pregnancy among women in South Africa

INTRODUCTION

Women who choose to conceive a baby with a partner living with HIV or a partner whose HIV serostatus is unknown in HIV-endemic settings need prevention strategies to mitigate HIV acquisition during conception and pregnancy.

METHODS AND ANALYSIS

We are conducting a single-arm longitudinal study offering oral tenofovirdisoproxil fumarate/emtricitabine (TDF/FTC) as pre-exposure prophylaxis (PrEP) for periconception use to 350 HIV-uninfected women in KwaZulu-Natal, South Africa. PrEP is offered as part of woman-centred safer conception programme that promotes couples-based HIV counselling and testing, antiretroviral therapy for partners who are HIV-infected, treatment for sexually transmitted infections and safer conception strategies, such as limiting condomless sex to peak fertility. We enrol HIV-uninfected women who are not currently pregnant, in a stable relationship (≥6 months) with a partner living with HIV or of unknown serostatus, and personal or partner plans for pregnancy in the next 12 months. We follow enrolled women for 12 months. Women who become pregnant are followed through pregnancy outcome, independent of their decisions regarding PrEP use. The primary objective of the study is to evaluate the uptake of and adherence to PrEP during the periconception period and pregnancy. Secondary outcomes include the uptake of other safer conception strategies. We also measure clinical outcomes including HIV seroconversion rates and pregnancy and infant outcomes. Finally, we will explore conduct and evaluate qualitative interviews in 25 participants to further inform our conceptual framework for periconception PrEP uptake and adherence among HIV-exposed women in South Africa.

ETHICS AND DISSEMINATION

The protocol has been approved by the Human Research Ethics Committee at the University of the Witwatersrand (Johannesburg, South Africa) and the Institutional Review Board of Partners Healthcare (Boston, Massachusetts, USA). Study findings will be made available to interested participants. Results will be presented to local health officials and stakeholders at meetings. Investigators will share the results at meetings and in manuscripts. De-identified quantitative data will be made available.

TRIAL REGISTRATION NUMBER

The protocol is registered with the South African Health Products Regulatory Agency (SAHPRA, formerly known as the Medicine Controls Council, MCC#20170131) and ClinicalTrials.gov (NCT03194308); Pre-results.

Comparing Self-Report Pre-Exposure Prophylaxis Adherence Questions to Pharmacologic Measures of Recent and Cumulative Pre-Exposure Prophylaxis Exposure

As pre-exposure prophylaxis (PrEP) effectiveness is strongly linked to adherence, we sought to determine if certain self-report measures could be used to inform objective PrEP adherence. We studied participants from the TAPIR study (a multicenter randomized study of daily text messages to support adherence to PrEP In At-Risk), a 48-week randomized controlled trial of HIV-uninfected men who have sex with men (MSM) randomized to receive text message to support adherence versus standard of care. Self-reported medication adherence was assessed using several validated measures modified for PrEP. Objective PrEP adherence was determined through dried blood spot (DBS) measurement of intracellular tenofovir diphosphate (TFV-DP) and emtricitabine triphosphate (FTC-TP). A summary of adherence was estimated using responses to the seven adherence items at weeks 12 and 48 using confirmatory factor analysis. Correlations between self-report questions and drug concentrations were estimated with Pearson's correlations for continuous outcomes and point-biserial correlations for dichotomous outcomes. Receiver operating characteristic (ROC) analyses were conducted to assess the performance of self-report measures in predicting protective or perfect TFV-DP concentrations. Of the 369 participants who completed week 12 or 48 visits, the mean age was 35 (standard deviation 9 years), with 79% White, 12% Black, and 29% Hispanic. Correlations between self-report measures of adherence (both individual items and the adherence factor) and quantifiable FTC-TP and continuous TFV-DP concentrations showed that all self-report measures were significantly associated with these objective measures. Compared to a summary measure of self-reported adherence, the 4-week percent taken question medication recall was the only self-report item similarly or more strongly associated with recent adherence and long-term protective and perfect adherence at weeks 12 and 48. ROC analysis also showed that 4-week percent taken question had a reasonable AUC (0.798 at week 12 and 0.758 at week 48) in predicting protective TFV-DP concentrations. All single-item self-report questions assessing PrEP adherence were significantly associated with biomarker quantification, with the 4-week percent taken question performing best. Therefore, in the absence of drug concentration measurements, a 4-week self-report percent taken question may be a good single-item measure of PrEP adherence.

Motivational Interviewing to Reduce Drug Use and HIV Incidence Among Young Men Who Have Sex With Men in Relationships and Are High Priority for Pre-Exposure Prophylaxis (Project PARTNER): Randomized Controlled Trial Protocol

Background

Men who have sex with men (MSM) currently account for more than two-thirds of new HIV diagnoses in the United States and, among young MSM (YMSM) aged 20 to 29 years, as many as 79% to 84% of new infections occur between primary partners. Contributing to HIV risk, YMSM use drugs at comparatively high rates. To date, no interventions have been developed that specifically address the unique needs of partnered YMSM or incorporate a focus on relationship factors in addressing personal motivation for change.

Objective

The study’s primary aim is to evaluate the efficacy of the PARTNER intervention and evaluate potential moderators or mediators of intervention effects. The study’s secondary aims were to gather ideographic data to inform a future effectiveness implementation study and develop a novel biomarker for pre-exposure prophylaxis (PrEP) adherence by analyzing PrEP drug levels in fingernails.

Methods

PARTNER is a 4-session motivational interviewing–based intervention that integrates video-based communication training to address drug use and HIV prevention among partnered YMSM. This study utilizes a randomized controlled trial design to compare the PARTNER intervention with an attention-matched psychoeducation control arm that provides information about HIV-risk reduction, PrEP, and substance use. Participants are randomized in a 1-to-1 ratio stratified on age disparity between partners, racial composition of the couple, and relationship length. Follow-up assessments are conducted at 3-, 6-, 9-, and 12-months postbaseline. The study recruits and enrolls 240 partnered YMSM aged between 18 to 29 years at a research center in New York City. Participants will be HIV-negative and report recent (past 30-day) drug use and condomless anal sex with casual partners; a nonmonogamous primary partner (regardless of HIV status); or a serodiscordant primary partner (regardless of sexual agreement). Primary outcomes (drug use and HIV sexual transmission risk behavior) are assessed via a Timeline Follow-back interview. Biological markers of outcomes are collected for drug use (fingernail assay), sexual HIV transmission risk (rectal and urethral gonorrhea and chlamydia testing), and PrEP adherence (dried blood spots and fingernails for a novel PrEP drug level assay).

Results

The study opened for enrollment in February 2018. Anticipated completion of enrollment is October 2021. Primary outcome analyses will begin after final follow-up completion.

Conclusions

Existing research on partnered YMSM within the framework of Couples Interdependence Theory (CIT) has suggested that relationship factors (eg, dyadic functioning and sexual agreements) are meaningfully related to drug use and HIV transmission risk. Results pertaining to the efficacy of the proposed intervention and the identification of putative moderators and mediators will substantially inform the tailoring of interventions for YMSM in relationships and contribute to a growing body of relationship science focused on enhancing health outcomes.

Trial Registration

ClinicalTrials.gov NCT03396367; https://clinicaltrials.gov/ct2/show/NCT03396367 (Archived by WebCite at http://www.webcitation.org/78ti7esTc.

International Registered Report Identifier (IRRID)

DERR1-10.2196/13015

High Adherence to HIV Pre-exposure Prophylaxis and No HIV Seroconversions Despite High Levels of Risk Behaviour and STIs: The Australian Demonstration Study PrELUDE

PrELUDE study evaluated daily pre-exposure prophylaxis (PrEP) in high-risk individuals in Australia. This open-label, single-arm study tested participants for HIV/STI and collected behavioural information three-monthly. We report trends over 18 months in medication adherence, side-effects, HIV/STI incidence and behaviour. 320 gay/bisexual men (GBM), 4 women and 3 transgender participants, followed on average 461 days, reported taking seven pills/week on 1,591 (88.5%) occasions and 4-6 pills/week on 153 (8.5%) occasions. No HIV infections were observed. STI incidence was high and stable, while gonorrhoea infections declined from 100.0 to 25.8/100 person-years between 6 and 15 months (p < 0.001). The number of HIV-positive and unknown-status sex partners, and condomless anal intercourse, significantly increased. In this high-risk cohort of mainly GBM, increases in risk behaviours and high STI incidence were not accompanied by HIV infections due to high adherence to daily PrEP. The study informed policy and further PrEP implementation among Australian GBM.

Dapivirine vaginal ring for HIV prevention: modelling health outcomes, drug resistance and cost-effectiveness

INTRODUCTION

A vaginal ring containing dapivirine is effective for HIV prevention as pre-exposure prophylaxis (PrEP). We evaluated the potential epidemiological impact and cost-effectiveness of dapivirine vaginal ring PrEP among 22- to 45-year-old women in KwaZulu-Natal, South Africa.

METHODS

Using mathematical modelling, we studied dapivirine vaginal ring PrEP implementation, either unprioritized, or prioritized based on HIV incidence (≥3% per year), age (22 to 29 years) or female sex worker status, alongside the implementation of voluntary medical male circumcision and antiretroviral therapy scaled-up to UNAIDS Fast-Track targets. Outcomes over the intervention (2019 to 2030) and lifetime horizons included cumulative HIV infections, life-years lived, costs and cost-effectiveness. We assessed the incremental cost-effectiveness ratios against the revealed willingness to pay ($500) and the standard (2017 per capita gross domestic product; $6161) cost-effectiveness thresholds for South Africa.

RESULTS

Compared to a reference scenario without PrEP, implementation of dapivirine vaginal ring PrEP, assuming 56% effectiveness and covering 50% of 22 to 29-year-old or high-incidence women, prevented 10% or 11% of infections by 2030 respectively. Equivalent, unprioritized coverage (30%) prevented fewer infections (7%), whereas 50% coverage of female sex workers had the least impact (4%). Drug resistance attributable to PrEP was modest (2% to 4% of people living with drug-resistant HIV). Over the lifetime horizon, dapivirine PrEP implementation among female sex workers was cost-saving, whereas incidence-based PrEP cost $1898 per life-year gained, relative to PrEP among female sex workers and $989 versus the reference scenario. In a scenario of 37% PrEP effectiveness, PrEP had less impact, but prioritization to female sex workers remained cost-saving. In uncertainty analysis, female sex worker PrEP was consistently cost-saving; and over the lifetime horizon, PrEP cost less than $6161 per life-year gained in over 99% of simulations, whereas incidence- and age-based PrEP cost below $500 per life-year gained in 61% and 49% of simulations respectively. PrEP adherence and efficacy, and the effectiveness of antiretroviral therapy for HIV prevention, were the principal drivers of uncertainty in the cost-effectiveness of PrEP.

CONCLUSIONS

Dapivirine vaginal ring PrEP would be cost-saving in KwaZulu-Natal if prioritized to female sex workers. PrEP's impact on HIV prevention would be increased, with potential affordability, if prioritized to women by age or incidence.

HIV pre-exposure prophylaxis (PrEP) awareness and acceptability among trans women: a review

Transgender (trans) women are disproportionally burdened by the HIV epidemic due to complex structural, psychosocial and biological factors. HIV pre-exposure prophylaxis (PrEP) is a biomedical prevention approach for people at substantial risk of acquiring HIV. This literature review assessed awareness, willingness to use, and barriers and facilitators for PrEP acceptability among trans women. A search was conducted through five databases and included studies with primary data and disaggregate results for trans women. Of 255 retrieved citations, 17 met the inclusion criteria and were included. Low to moderate knowledge about PrEP was observed among studies. However, willingness to use PrEP was predominantly high. Frequent barriers to PrEP acceptability included concerns about side effects, cost, hormone therapy, adherence, PrEP-related stigma and interaction with healthcare workers. Facilitators included perceived reduction of HIV risk, fear of HIV/AIDS and reduced dependence on partners. Findings suggest elevated interest in PrEP and highlight important barriers and facilitators that should be specifically addressed to optimize PrEP uptake and use among this highly vulnerable population.

Correlates of nonadherence to key population-led HIV pre-exposure prophylaxis services among Thai men who have sex with men and transgender women

Background

Based on government estimates from the Asian Epidemic Model, new infections among men who have sex with men (MSM) and transgender women (TGW) in Thailand are forecast to proportionally increase over time. Daily oral Pre-exposure prophylaxis (PrEP) protects against HIV acquisition when used as prescribed. The “Princess PrEP” program is the first key population-led (PrEP) initiative under Thai royal patronage with an aim to scale up countrywide implementation of PrEP.

Methods

Retention in and adherence to key population-led HIV PrEP services among HIV-uninfected Thai MSM and TGW was examined in four provinces: Bangkok, Chonburi, Chiang Mai, and Songkhla. HIV, HBsAg, creatinine tests, and self-administered questionnaires were performed during baseline measures. Participants were followed up after month 1, at month 3, then every 3 months. Correlates of nonadherence and loss to follow up at 1 month were assessed using linear regression models.

Results

37.4% of the participants reported low adherence to services (≤ 3 pills/week or missed clinic schedule at month 1). Factors associated with low adherence included younger age (25 years and under) (adjusted odds ratio (aOR): 1.49, 95% confidence interval (95% CI: 1.01–2.21, p = 0.044), being a TGW (aOR: 2.2, 95% CI: 1.27–3.83, p = 0.005), and whether the participant had not previously accessed services at the clinic (aOR = 1.68, 95% CI: 1.03–2.76, p = 0.04). Additionally, participants in Chonburi (the only TGW site) showed significantly lower adherence than those in the other three provinces (aOR: 2.91, 95% CI: 1.55–5.45, p = 0.001).

Conclusion

Urgent, innovative interventions for early PrEP adherence support among vulnerable sub-populations such as younger users, TGW, and new clients are needed to maximize prevention strategy in Thailand.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6645-0) contains supplementary material, which is available to authorized users.

HIV prevention cascades: A unifying framework to replicate the successes of treatment cascades

Many countries are off track to meet targets for reducing new HIV infections. HIV prevention cascades have been proposed to assist in the implementation and monitoring of HIV prevention programmes by identifying gaps in the steps required for effective use of prevention methods, similar to HIV treatment cascades. However, lack of a unifying framework impedes widespread use of prevention cascades. Building on a series of consultations, we propose an HIV prevention cascade consisting of three key domains of motivation, access, and effective use in a priority population. This three-step cascade can be used for routine monitoring and advocacy, particularly by attaching 90-90-90-style targets. Further characterisation of reasons for gaps across motivation, access, or effective use allows for a comprehensive framework, guiding identification of relevant responses and platforms for interventions. Linking the prevention cascade, reasons for gaps, and interventions reconciles the different requirements of prevention cascades, providing a unifying framework.

Early antiretroviral therapy and daily pre-exposure prophylaxis for HIV prevention among female sex workers in Cotonou, Benin: a prospective observational demonstration study

INTRODUCTION

In sub-Saharan Africa, HIV prevalence remains high, especially among key populations. In such situations, combination prevention including clinical, behavioural, structural and biological components, as well as adequate treatment are important. We conducted a demonstration project at the Dispensaire IST, a clinic dedicated to female sex workers (FSWs) in Cotonou, on early antiretroviral therapy (E-ART, or immediate "test-and-treat") and pre-exposure prophylaxis (PrEP). We present key indicators such as uptake, retention and adherence.

METHODS

In this prospective observational study, we recruited FSWs from October 4th 2014 to December 31st 2015 and followed them until December 31st 2016. FSWs were provided with daily tenofovir disoproxil fumarate/emtricitabine (Truvada® ) for PrEP or received a first-line antiretroviral regimen as per Benin guidelines. We used generalized estimating equations to assess trends in adherence and sexual behaviour.

RESULTS

Among FSWs in the catchment area, HIV testing coverage within the study framework was 95.5% (422/442). At baseline, HIV prevalence was 26.3% (111/422). Among eligible FSWs, 95.5% (105/110) were recruited for E-ART and 88.3% (256/290) for PrEP. Overall retention at the end of the study was 59.0% (62/105) for E-ART and 47.3% (121/256) for PrEP. Mean (±SD) duration of follow-up was 13.4 (±7.9) months for E-ART and 11.8 (±7.9) months for PrEP. Self-reported adherence was over 90% among most E-ART participants. For PrEP, adherence was lower and the proportion with 100% adherence decreased over time from 78.4% to 56.7% (p-trend < 0.0001). During the 250.1 person-years of follow-up among PrEP initiators, two seroconversions occurred (incidence 0.8/100 person-years (95% confidence interval: 0.3 to 1.9/100 person-years)). The two seroconverters had stopped using PrEP for at least six months before being found HIV-infected. In both groups, there was no evidence of reduced condom use.

CONCLUSIONS

This study provides data on key indicators for the integration of E-ART and PrEP into the HIV prevention combination package already offered to FSWs in Benin. PrEP may be more useful as an individual intervention for adherent FSWs rather than a specific public health intervention. E-ART was a more successful intervention in terms of retention and adherence and is now offered to all key populations in Benin.

STUDY REGISTRATION

ClinicalTrials.gov NCT02237.

Short Communication: Bioequivalence of Tenofovir and Emtricitabine After Coencapsulation with the Proteus Ingestible Sensor

Adherence to tenofovir disoproxil fumarate/emtricitabine (TDF/FTC, Truvada^®) is the primary determinant of HIV pre-exposure prophylaxis (PrEP) efficacy. Despite its importance, limitations exist in current methods of adherence quantification, restricting their implementation in the clinic. Proteus Discover (Proteus Digital Health^®) can measure the time of each dose using an ingestible sensor that is coencapsulated with medication. In this study, the bioequivalence of coencapsulated TDF/FTC with the Proteus sensor was compared relative to unencapsulated drug. This was a 1:1 randomized cross-over study in which healthy participants received a single dose of unencapsulated and coencapsulated TDF/FTC. A 14-day washout separated each period. Blood was collected at predose and at 0.25, 0.5, 1, 2, 4, 6, 10, 24, 48, and 72 h postdose. Plasma concentrations were determined by LC-MS/MS methods, with a 10 ng/mL lower limit of quantitation (LLOQ) for both tenofovir (TFV) and FTC. Noncompartmental analysis was carried out with Phoenix^® WinNonlin^® for maximum concentrations (C_max), area under the concentration-time curve from time 0 to the last measured time point (AUC_last) and AUC extrapolated to infinity (AUC_inf). Geometric mean ratios were calculated for each parameter and bioequivalence was defined as the 90% confidence interval (CI) of each ratio being within 80%-125%. Twenty-four participants (11 males; 19 white, 3 African American, and 2 Hispanic) completed both visits. Mean ± SD age was 28 ± 4 years and weight was 74 ± 14 kg. The 90% CIs for TFV C_max, AUC_last, and AUC_inf were 89%-119%, 94%-111%, and 96%-111%, respectively. The 90% CIs for FTC C_max, AUC_last, and AUC_inf were 96%-120%, 96%-108%, and 96%-108%, respectively. Bioequivalence was observed for the coencapsulation of TDF/FTC with the Proteus ingestible sensor, as assessed by a rigorously conducted pharmacokinetic study. Future studies will evaluate the utility and effectiveness of the sensor system as a tool to monitor PrEP adherence in clinical settings.

Consensus statement: Supporting Safer Conception and Pregnancy For Men And Women Living with and Affected by HIV

Safer conception interventions reduce HIV incidence while supporting the reproductive goals of people living with or affected by HIV. We developed a consensus statement to address demand, summarize science, identify information gaps, outline research and policy priorities, and advocate for safer conception services. This statement emerged from a process incorporating consultation from meetings, literature, and key stakeholders. Three co-authors developed an outline which was discussed and modified with co-authors, working group members, and additional clinical, policy, and community experts in safer conception, HIV, and fertility. Co-authors and working group members developed and approved the final manuscript. Consensus across themes of demand, safer conception strategies, and implementation were identified. There is demand for safer conception services. Access is limited by stigma towards PLWH having children and limits to provider knowledge. Efficacy, effectiveness, safety, and acceptability data support a range of safer conception strategies including ART, PrEP, limiting condomless sex to peak fertility, home insemination, male circumcision, STI treatment, couples-based HIV testing, semen processing, and fertility care. Lack of guidelines and training limit implementation. Key outstanding questions within each theme are identified. Consumer demand, scientific data, and global goals to reduce HIV incidence support safer conception service implementation. We recommend that providers offer services to HIV-affected men and women, and program administrators integrate safer conception care into HIV and reproductive health programs. Answers to outstanding questions will refine services but should not hinder steps to empower people to adopt safer conception strategies to meet reproductive goals.

Pre-exposure prophylaxis (PrEP) in an era of stalled HIV prevention: Can it change the game?

Pre-exposure prophylaxis (PrEP) for HIV prevention has evolved significantly over the years where clinical trials have now demonstrated the efficacy of oral PrEP, and the field is scaling-up implementation. The WHO and UNAIDS have made PrEP implementation a priority for populations at highest risk, and several countries have developed guidelines and national plans accordingly, largely based on evidence generated by demonstration projects. PrEP presents the opportunity to change the face of HIV prevention by offering a new option for protection against HIV and disrupting current HIV prevention systems. Nevertheless, as with all new technologies, both practical and social requirements for implementation must be taken into account if there is to be sustained and widespread adoption, which will also apply to forthcoming prevention technologies. Defining and building success for PrEP within the scope of scale-up requires careful consideration. This review summarises where the PrEP field is today, lessons learned from the past, the philosophy and practicalities of how successful programming may be defined, and provides perspectives of costs and affordability. We argue that a successful PrEP programme is about effective intervention integration and ultimately keeping people HIV negative.

Preexposure Prophylaxis of HIV Infection: the Role of Clinical Practices in Ending the HIV Epidemic

PURPOSE OF REVIEW

The aim of this study is to summarise the recent evidence from high-income settings about providers' ability to deliver on the UNAIDS goal of at least three million people at substantial risk of HIV infection with PrEP by 2020, including awareness and knowledge about PrEP, willingness to prescribe PrEP, current levels of prescribing and service delivery models and issues.

RECENT FINDINGS

Awareness about PrEP among health providers is growing, but at different pace depending on provider type. HIV and sexual health specialists are more likely to have knowledge about PrEP than generalists, and to be willing to prescribe it, mainly because of their closer contact with people at high risk for HIV and better risk assessment skills. There is still no consensus as to who should be responsible for providing PrEP, but clearly all hands on deck will be useful in delivering on the international target of three million people at substantial risk for HIV on PrEP by 2020. Only about 5% of the target has been reached so far. Local guidance and large-scale education and information programs for clinicians will be necessary to upskill health providers. High cost of PrEP is still a major barrier for its broad implementation, even in countries were PrEP roll-out has started. Health services are facing major structural challenges due to implementation of PrEP services to a substantial volume of patients. The early implementation experiences demonstrated that PrEP can be successfully delivered across a variety of settings, and a broad range of strategies and models of care can streamline PrEP delivery. Education of the providers and PrEP cost solutions will be essential for rapid roll-out of PrEP.

Potential of conventional & bispecific broadly neutralizing antibodies for prevention of HIV-1 subtype A, C & D infections

There is great interest in passive transfer of broadly neutralizing antibodies (bnAbs) and engineered bispecific antibodies (Abs) for prevention of HIV-1 infections due to their in vitro neutralization breadth and potency against global isolates and long in vivo half-lives. We compared the potential of eight bnAbs and two bispecific Abs currently under clinical development, and their 2 Ab combinations, to prevent infection by dominant HIV-1 subtypes in sub-Saharan Africa. Using in vitro neutralization data for Abs against 25 subtype A, 100 C, and 20 D pseudoviruses, we modeled neutralization by single Abs and 2 Ab combinations assuming realistic target concentrations of 10μg/ml total for bnAbs and combinations, and 5μg/ml for bispecifics. We used IC80 breadth-potency, completeness of neutralization, and simultaneous coverage by both Abs in the combination as metrics to characterize prevention potential. Additionally, we predicted in vivo protection by Abs and combinations by modeling protection as a function of in vitro neutralization based on data from a macaque simian-human immunodeficiency virus (SHIV) challenge study. Our model suggests that nearly complete neutralization of a given virus is needed for in vivo protection (~98% neutralization for 50% relative protection). Using the above metrics, we found that bnAb combinations should outperform single bnAbs, as expected; however, different combinations are optimal for different subtypes. Remarkably, a single bispecific 10E8-iMAb, which targets HIV Env and host-cell CD4, outperformed all combinations of two conventional bnAbs, with 95-97% predicted relative protection across subtypes. Combinations that included 10E8-iMAb substantially improved protection over use of 10E8-iMAb alone. Our results highlight the promise of 10E8-iMAb and its combinations to prevent HIV-1 infections in sub-Saharan Africa.

A Mobile Health Strategy to Support Adherence to Antiretroviral Preexposure Prophylaxis

Preexposure prophylaxis is a highly protective HIV prevention strategy, yet nonadherence can significantly reduce its effectiveness. We conducted a mixed methods evaluation of a mobile health intervention (iText) that utilized weekly bidirectional text or e-mail support messages to encourage preexposure prophylaxis (PrEP) adherence among participants in the multi-site iPrEx open-label extension study. A convenience sample of PrEP users from the San Francisco and Chicago sites participated in a 12-week pilot study. Fifty-six men who have sex with men were enrolled; a quarter of them were less than 30 years of age, 13% were black/African American, 11% were Latino, and most (88%) completed some college. Two-thirds opted for text message delivery. Of the 667 messages sent, only 1 individual requested support; initial nonresponse was observed in 22% and was higher among e-mail compared to text message recipients. Poststudy, a majority of participants would recommend the intervention to others, especially during PrEP initiation. Moreover, younger participants and men of color were more likely to report that they would use the iText strategy if it were available to them. Several participants commented that while they were aware that the messages were automated, they felt supported and encouraged that “someone was always there.” Study staff reported that the intervention is feasible to administer and can be incorporated readily into clinic flow. A pre–post intervention regression discontinuity analysis using clinic-based pill counts showed a 50% reduction in missed doses [95% confidence interval (CI) 16–71; p = 0.008] and 77% (95% CI 33–92; p = 0.007) when comparing pill counts at quarterly visits just before and after iText enrollment. A mobile health intervention using weekly bidirectional messaging was highly acceptable and demonstrated promising effects on PrEP adherence warranting further evaluation for efficacy in a randomized controlled trial.

Feasibility, Acceptability, and Adherence with Short-Term HIV Preexposure Prophylaxis in Female Sexual Partners of Migrant Miners in Mozambique

BACKGROUND

Preexposure prophylaxis (PrEP) offers protection from HIV acquisition if taken as prescribed. We evaluated the feasibility, acceptability, and adherence with short-term PrEP among female sexual partners of migrant miners in Mozambique.

METHODS

HIV-negative female sexual partners of migrant miners were offered daily tenofovir/emtricitabine (TDF/FTC) for 6 weeks concurrent with miners' return home. Study visits occurred at baseline, week 4, 6, and 8. Dried blood spots (DBSs) were collected at week 4 and 6.

RESULTS

Seventy-four women (median age: 42 years) were enrolled, 95% reported having 1 sexual partner and 80% reported never or rarely using condoms. At baseline, 41% had never tested for HIV; 65% were unaware of partners' HIV status. Of all women, 72 (97%) initiated PrEP, 7 (9%) discontinued PrEP before week 6; only 1 due to adverse events. Missed doses in the last week were self-reported by 8% and 3% of women at week 4 and 6, respectively. Of 66 (89%) women with DBS at week 4, 79% had detectable tenofovir diphosphate (TFV-DP) and 44% had levels consistent with ≥4 pills/wk (≥700 fmol/punch). Of 63 (88%) women with DBS at week 6, 76% had detectable TFV-DP and 42% had levels consistent with ≥4 pills/wk.

CONCLUSIONS

In this first study assessing the use of short-term PrEP, a high percent of female partners of migrant workers initiated PrEP and had detectable DP levels during follow-up. Further efforts are needed to enhance adherence to ensure protection from HIV acquisition. Short-term PrEP offers promise for populations who are at high risk of HIV during specific periods of time.

Comparison of Measures of Adherence to Human Immunodeficiency Virus Preexposure Prophylaxis Among Adolescent and Young Men Who Have Sex With Men in the United States

Background

Young men-who-have-sex-with-men (MSM) are disproportionately impacted by human immunodeficiency virus (HIV). Preexposure prophylaxis (PrEP) could reduce HIV acquisition among youth, but suboptimal adherence threatens effectiveness. Optimal metrics of PrEP adherence among adolescents have remain undefined.

Methods

The Adolescent Trials Network 110/113 studies provided daily oral PrEP with tenofovir (TFV) disoproxil fumarate/emtricitabine over 48 weeks to a diverse population of MSM (aged 15-22 years). Self-reported adherence was assessed and PrEP drug concentrations measured from hair and dried blood spot (DBS) samples; 23% of participants received Wisepill electronic monitoring devices. The average number of PrEP doses per week taken was estimated, and concordance between measures assessed.

Results

Among 243 participants, hair samples were collected at 1186/1238 (96%) person-visits. The concordance of TFV levels in hair and TFV-diphosphate in DBS around thresholds consistent with taking ≥4 and 7 PrEP doses/week was high (76% and 80%). Hair and DBS concentrations correlated poorly with self-report and Wisepill metrics. Through week 12, 40%-60% of participants (by hair and DBS), ≤31% (Wisepill), and >85% (self-report) were estimated to have taken ≥4 PrEP doses/week (a threshold associated with protection among MSM). For all measures except self-report, adherence declined over time, with half of participants taking <2 doses/week by week 48.

Conclusions

Among youth on PrEP, adherence waned over time. Self-report overestimated adherence, and use of Wisepill was limited. Hair collection was highly acceptable and provided similar interpretations to DBS. Incorporation of either metric in future PrEP studies among youth could identify suboptimal adherence and trigger interventions.

Princess PrEP program: the first key population-led model to deliver pre-exposure prophylaxis to key populations by key populations in Thailand

Background No data are available on the feasibility of pre-exposure prophylaxis (PrEP) delivered by trained key population (KP) community health workers. Herein we report data from the KP-led Princess PrEP program serving men who have sex with men (MSM) and transgender women (TGW) in Thailand. Methods: From January 2016 to December 2017, trained MSM and TGW community health workers delivered same-day PrEP service in community health centres, allowing clients to receive one PrEP bottle to start on the day of HIV-negative testing. Visits were scheduled at Months 1 and 3, and every 3 months thereafter. Uptake, retention and adherence to PrEP services and changes in risk behaviours over time are reported. Results: Of 1467 MSM and 230 TGW who started PrEP, 44.1% had had condomless sex in the past 3 months. At Months 1, 3, 6, 9 and 12, retention was 74.2%, 64.0%, 56.2%, 46.7% and 43.9% respectively (lower in TGW than MSM at all visits; P&lt;0.001), with adherence to at least four PrEP pills per week self-reported by 97.4%, 96.8%, 96.5%, 97.5% and 99.5% of respondents respectively (no difference between MSM and TGW). Logistic regression analysis identified age &gt;25 years, being MSM and having at least a Bachelors degree significantly increased retention. Condomless sex did not change over the 12-month period (from 47.2% to 45.2%; P=0.20). New syphilis was diagnosed in 4.9% and 3.0% of PrEP clients at Months 6 and 12 (cf. 7.0% at baseline; P=0.007). Among PrEP adherers and non-adherers, there were one and six HIV cases of seroconversion respectively, which resulted in corresponding HIV incidence rates (95% confidence interval) of 0.27 (0.04–1.90) and 1.36 (0.61–3.02) per 100 person-years. Conclusion: Our KP-led PrEP program successfully delivered PrEP to MSM and TGW. Innovative retention supports are needed, especially for TGW and those who are young or with lower education levels. To scale-up and sustain KP-led PrEP programs, strong endorsement from international and national guidelines is necessary.

Hypo-osmolar Formulation of Tenofovir (TFV) Enema Promotes Uptake and Metabolism of TFV in Tissues, Leading to Prevention of SHIV/SIV Infection

Oral preexposure prophylaxis (PrEP) has been approved for prophylaxis of HIV-1 transmission but is associated with high costs and issues of adherence. Protection from anal transmission of HIV using topical microbicides and methods congruent with sexual behavior offers the promise of improved adherence. We compared the pharmacokinetics (PK) and ex vivo efficacy of iso-osmolar (IOsm) and hypo-osmolar (HOsm) rectal enema formulations of tenofovir (TFV) in rhesus macaques. Single-dose PK of IOsm or HOsm high-dose (5.28 mg/ml) and low-dose (1.76 mg/ml) formulations of TFV enemas were evaluated for systemic uptake in blood, colorectal biopsy specimens, and rectal CD4⁺ T cells. Markedly higher TFV concentrations were observed in plasma and tissues after administration of the HOsm high-dose formulation than with all other formulations tested. TFV and TFV diphosphate (TFV-DP) concentrations in tissue correlated for the HOsm high-dose formulation, demonstrating rapid uptake and transformation of TFV to TFV-DP in tissues. TFV-DP amounts in tissues collected at 1 and 24 h were 7 times and 5 times higher, respectively (P < 0.01), than the ones collected in tissues with the IOsm formulation. The HOsm high-dose formulation prevented infection in ex vivo challenges of rectal tissues collected at 1, 24, and 72 h after the intrarectal dosing, whereas the same TFV dose formulated as an IOsm enema was less effective.

Brief Report: PrEP Use During Periods of HIV Risk Among East African Women in Serodiscordant Relationships

BACKGROUND

Pre-exposure prophylaxis (PrEP) is efficacious for African women at risk for HIV, but data on adherence outside clinical trials are sparse. We describe the persistence and execution of PrEP use among women participating in a large open-label PrEP demonstration project, particularly during periods of HIV risk.

SETTING AND METHODS

Three hundred ten HIV-uninfected women in HIV serodiscordant couples in Kenya and Uganda were offered and accepted PrEP. Electronic monitoring caps were used to measure daily PrEP adherence. Time on PrEP while at risk for HIV (when the HIV-infected partner was on antiretroviral therapy <6 months) and weekly adherence while on PrEP were calculated and compared among older and younger (<25 years old) women.

RESULTS

As defined above, women were at risk for HIV for an average of 361 days; 54% took PrEP during their entire risk period and 24% stopped but restarted PrEP during their risk period. While on PrEP, women took ≥6 doses/wk for 78% of weeks [67% of weeks for women aged <25 years, 80% of weeks for women aged ≥25 years (P < 0.001)], and ≥4 doses for 88% of weeks [80% for those <25, 90% for those ≥25, (P < 0.001)]. Compared with historical, risk-matched controls, HIV incidence was reduced 93% (95% confidence interval: 77% to 98%) for all women and 91% (95% confidence interval: 29% to 99%) among women aged <25 years.

CONCLUSION

Women, including young women, in HIV-serodiscordant couples took PrEP successfully over sustained periods of risk. Although young women had lower adherence than older women, they achieved strong protection, which suggests that women can align PrEP use to periods of risk and imperfect adherence can still provide substantial benefit.

Pre-Exposure Prophylaxis for HIV Prevention: Safety Concerns

Available evidence supports the efficacy of pre-exposure prophylaxis (PrEP) in decreasing the incidence of human immunodeficiency virus (HIV) infection among high-risk individuals, especially when used in combination with other behavioural preventive methods. Safety concerns about PrEP present challenges in the implementation and use of PrEP. The aim of this review is to discuss safety concerns observed in completed clinical trials on the use of PrEP. We performed a literature search on PrEP in PubMed, global advocacy for HIV prevention (Aids Vaccine Advocacy Coalition) database, clinical trials registry " http://www.clinicaltrials.gov " and scholar.google, using combination search terms 'pre-exposure prophylaxis', 'safety concerns in the use of pre-exposure prophylaxis', 'truvada use as PrEP', 'guidelines for PrEP use', 'HIV pre-exposure prophylaxis' and 'tenofovir' to identify clinical trials and literature on PrEP. We present findings associated with safety issues on the use of PrEP based on a review of 11 clinical trials on PrEP with results on safety and efficacy as at April 2016. We also reviewed findings from routine real-life practice reports. The pharmacological intervention for PrEP was tenofovir disoproxil fumarate/emtricitabine in a combined form as Truvada^® or tenofovir as a single entity. Both products are efficacious for PrEP and seem to have a good safety profile. Regular monitoring is recommended to prevent long-term toxic effects. The main adverse effects observed with PrEP are gastrointestinal related; basically mild to moderate nausea, vomiting and diarrhea. Other adverse drug effects worth monitoring are liver enzymes, renal function and bone mineral density. PrEP as an intervention to reduce HIV transmission appears to have a safe benefit-risk profile in clinical trials. It is recommended for widespread use but adherence monitoring and real-world safety surveillance are critical in the post-marketing phase to ensure that the benefits observed in clinical trials are maintained in real-world use.

Adolescent pre-exposure prophylaxis for HIV prevention: current perspectives

Adolescents are a critical population that is disproportionately impacted by the HIV epidemic. More than 2 million adolescents between the age group of 10 and 19 years are living with HIV, and millions are at risk of infection. HIV risks are considerably higher among girls, especially in high-prevalence settings such as eastern and southern Africa. In addition to girls, there are other vulnerable adolescent subgroups, such as teenagers, who use intravenous (IV) drugs, gay and bisexual boys, transgender youth, male sex workers, and people who fall into more than one of these categories. Pre-exposure prophylaxis (PrEP) is a new intervention for people at high risk for acquiring HIV, with an estimated HIV incidence of >3%. Recent data from trials show evidence of the efficacy of PrEP as a powerful HIV prevention tool in high-risk populations, including men who have sex with men, HIV-1-serodiscordant heterosexual couples, and IV drug users. The reported efficacy in those trials of the daily use of oral tenofovir, alone or in combination with emtricitabine, to prevent HIV infection ranged from 44% to 75% and was heavily dependent on adherence. Despite the proven efficacy of PrEP in adult trials, concerns remain about its feasibility in real-life scenarios due to stigma, cost, and limited clinician experience with PrEP delivery. Recent studies are attempting to expand the inquiry into the efficacy of such HIV prophylaxis approaches in adolescent populations, but there are still many gaps in knowledge, and no country has yet approved it for use with adolescents. The aim of this review was to identify and summarize the evidence from studies on PrEP for adolescents. We have compiled and reviewed published studies focusing on safety, feasibility, adherence to therapeutics, self-perception, and legal issues related to PrEP in people aged between 10 and 24 years.

Alignment of adherence and risk for HIV acquisition in a demonstration project of pre-exposure prophylaxis among HIV serodiscordant couples in Kenya and Uganda: a prospective analysis of prevention-effective adherence

Introduction: Adherence is essential for pre-exposure prophylaxis (PrEP) to protect against HIV acquisition, but PrEP use need not be life-long. PrEP is most efficient when its use is aligned with periods of risk – a concept termed prevention-effective adherence. The objective of this paper is to describe prevention-effective adherence and predictors of adherence within an open-label delivery project of integrated PrEP and antiretroviral therapy (ART) among HIV serodiscordant couples in Kenya and Uganda (the Partners Demonstration Project).

Methods: We offered PrEP to HIV-uninfected participants until the partner living with HIV had taken ART for ≥6 months (a strategy known as “PrEP as a bridge to ART”). The level of adherence sufficient to protect against HIV was estimated in two ways: ≥4 and ≥6 doses/week (per electronic monitoring). Risk for HIV acquisition was considered high if the couple reported sex with <100% condom use before six months of ART, low if they reported sex but had 100% condom use and/or six months of ART and very low if no sex was reported. We assessed prevention-effective adherence by cross-tabulating PrEP use with HIV risk and used multivariable regression models to assess predictors of ≥4 and ≥6 doses/week.

Results: A total of 985 HIV-uninfected participants initiated PrEP; 67% were male, median age was twenty-nine years, and 67% reported condomless sex in the month before enrolment. An average of ≥4 doses and ≥6 doses/week were taken in 81% and 67% of participant-visits, respectively. Adherence sufficient to protect against HIV acquisition was achieved in 75–88% of participant-visits with high HIV risk. The strongest predictor of achieving sufficient adherence was reporting sex with the study partner who was living with HIV; other statistically significant predictors included no concerns about daily PrEP, pregnancy or pregnancy intention, females aged >25 years, older male partners and desire for relationship success. Predictors of not achieving sufficient adherence were no longer being a couple, delayed PrEP initiation, >6 months  of follow-up, ART use >6 months  by the partner living with HIV and problem alcohol use.

Conclusions: Over three-quarters of participant-visits by HIV-uninfected partners in serodiscordant couples achieved prevention-effective adherence with PrEP. Greater adherence was observed during months with HIV risk and the strongest predictor of achieving sufficient adherence was sexual activity.

Urine assay for tenofovir to monitor adherence in real time to tenofovir disoproxil fumarate/emtricitabine as pre-exposure prophylaxis

OBJECTIVES

Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) is approved for pre-exposure prophylaxis (PrEP) against HIV infection. Adherence is critical for the success of PrEP, but current adherence measurements are inadequate for real-time adherence monitoring. We developed and validated a urine assay to measure tenofovir (TFV) to objectively monitor adherence to PrEP.

METHODS

We developed a urine assay using high-performance liquid chromatography coupled to tandem mass spectrometry with high sensitivity/specificity for TFV that allowed us to determine TFV concentrations in log₁₀ categories between 0 and 10 000 ng/mL. We validated the assay in three cohorts: (1) HIV-positive subjects with undetectable viral loads on a TDF/FTC-based regimen, (2) healthy HIV-negative subjects who received a single dose of TDF/FTC, and (3) HIV-negative subjects receiving daily TDF/FTC as PrEP for 24 weeks.

RESULTS

The urine assay detected TFV with greater sensitivity than plasma-based measures and with a window of measurements within 7 days of the last TDF/FTC dose. Based on the urine log-linear clearance after the last dose and its concordance with all detectable plasma levels, a urine TFV concentration > 1000 ng/mL was identified as highly predictive of the presence of TFV in plasma at > 10 ng/mL. The urine assay was able to distinguish high and low adherence patterns within the last 48 h (> 1000 ng/mL versus 10-1000 ng/mL), as well as nonadherence (< 10 ng/mL) extended over at least 1 week prior to measurement.

CONCLUSIONS

We provide proof of concept that a semiquantitative urine assay measuring levels of TFV could be further developed into a point-of-care test and be a useful tool to monitor adherence to PrEP.

Enhancing PrEP Access for Black and Latino Men Who Have Sex With Men

OBJECTIVE

Implementation of HIV pre-exposure prophylaxis (PrEP) programs for populations with highest incidence is critical to reducing new infections in the United States. Black and Latino men who have sex with men (BLMSM) are disproportionately burdened by HIV. We examined differences in perceived barriers and facilitators to PrEP access for BLMSM compared with other men who have sex with men (MSM).

METHOD

MSM who met the Centers for Disease Control and Prevention criteria for PrEP (n = 491) completed measures of barriers and facilitators to PrEP at the systems, provider, and individual levels. Multivariate analyses examined differences by race/ethnicity, adjusting for other sociodemographic factors.

RESULTS

Compared with other MSM, BLMSM (56% of the sample) were more likely to have public insurance and to access health care via public clinics [adjusted odds ratio(aOR) 3.2, P < 0.001; aOR 2.4, P < 0.01]. BLMSM were more likely to regard having to talk to their doctor about their sex life as a barrier to PrEP (aOR 3.7, P < 0.001) and were less likely to endorse agency in medical decision making (aOR 0.58, P < 0.001). BLMSM were more likely to report PrEP stigma (aOR 2.3, P < 0.001) and concerns regarding PrEP efficacy (aOR 1.6, P < 0.05). BLMSM were more likely to consider access to free sexual health care (aOR 2.1, P < 0.01) and additional supportive services, eg, counseling (aOR 3.1, P < 0.001) or text-based support (aOR 2.9, P < 0.001) to be significant facilitators of PrEP use.

CONCLUSIONS

Findings suggest specific points of multilevel intervention to increase PrEP access for BLMSM and increase representation of BLMSM along the PrEP continuum of care.

High Willingness to Use HIV Pre-Exposure Prophylaxis Among Transgender Women in Argentina

Purpose: In Argentina, transgender women face a disproportionately high prevalence of HIV infection (34%). Although not currently approved in Argentina, pre-exposure prophylaxis (PrEP) may offer a potential effective HIV prevention tool for this population. In this study, we assessed the willingness to use PrEP among transgender women in Argentina. Methods: Data were drawn from a nationwide cross-sectional survey conducted among transgender women in 2013. Using multivariable logistic regression, we assessed the prevalence of and factors associated with willingness to use PrEP among transgender women with negative or unknown HIV status. Results: This study included 337 transgender women (278 HIV negative and 59 with unknown HIV status), most of whom had a history of sex work involvement (81.8%). Overall, 301 (89.3%) expressed willingness to use PrEP. In a multivariable analysis, having casual sexual partners was positively associated with willingness to use PrEP (adjusted odds ratio [AOR]=4.26, 95% confidence interval [CI] 1.73-10.51), while discrimination by healthcare workers was negatively associated (AOR=0.33, 95% CI 0.12-0.88). Conclusion: We found high levels of willingness to use PrEP among transgender women in Argentina, suggesting that there is high perception of HIV risk in this population. However, discrimination by healthcare workers was a strong negative correlate of willingness to use PrEP, suggesting that multilevel interventions that address gender-based stigma in healthcare settings will be critical for the success of PrEP as an HIV prevention strategy in this population.

Preventing HIV among adolescents with oral PrEP: observations and challenges in the United States and South Africa

INTRODUCTION

Adolescents and young adults aged <25 are a key population in the HIV epidemic, with very high HIV incidence rates in many geographic settings and a large number who have limited access to prevention services. Thus, any biomedical HIV prevention approach should prepare licensure and implementation strategies for young populations. Oral pre-exposure prophylaxis (PrEP) is the first antiretroviral-based prevention intervention with proven efficacy across many settings and populations, and regulatory and policy approvals at global and national levels are occurring rapidly. We discuss available data from studies in the United States and South Africa on the use of oral PrEP for HIV prevention in adolescent minors, along with some of the implementation challenges.

DISCUSSION

Ongoing studies in the United States and South Africa among youth under the age of 18 should provide the safety data needed by the end of 2016 to contribute to licensure of Truvada as daily PrEP in adolescents. The challenges of completing these studies as well as foreseeable broader challenges highlighted by this work are presented. Adherence to daily PrEP is a greater challenge for younger populations, and poor adherence was associated with decreased efficacy in all PrEP trials. Individual-level barriers include limited familiarity with antiretroviral-based prevention, stigma, product storage, and social support. Structural challenges include healthcare financing for PrEP, clinician acceptability and comfort with PrEP delivery, and the limited youth-friendly health services available. These challenges are discussed in the context of the work done to date in the United States and South Africa, but will likely be magnified in the setting of limited resources in many other countries that are heavily impacted by HIV.

CONCLUSIONS

Adolescent populations are particularly vulnerable to HIV, and oral PrEP in these populations is likely to have an impact on population-level HIV incidence. The challenges of disseminating an HIV biomedical prevention tool requiring daily usage in adolescents are formidable, but addressing these issues and starting dialogues will lay the groundwork for the many other HIV prevention tools now being developed and tested.

The future of PrEP among transgender women: the critical role of gender affirmation in research and clinical practices

INTRODUCTION

Globally, transgender ("trans") women are one of the key populations most disproportionately impacted by HIV. Pre-exposure prophylaxis (PrEP) is the newest and most promising biomedical HIV prevention intervention to date. This paper reviews relevant literature to describe the current state of the science and describes the potential role of PrEP among trans women, including a discussion of unique considerations for maximizing the impact of PrEP for this vulnerable population.

METHODS

Available information, including but not limited to existing scientific literature, about trans women and PrEP was reviewed and critiqued based on author expertise, including PrEP clinical trials and rollout.

RESULTS

To date, PrEP demonstration projects and clinical trials have largely excluded trans women, or have not included them in a meaningful way. Data collection strategies that fail to identify trans women in clinical trials and research further limit the ability to draw conclusions about trans women's unique needs and devise strategies to meet them. Gender-affirming providers and clinic environments are essential components of any sexual health programme that aims to serve trans women, as they will largely avoid settings that may result in stigmatizing encounters and threats to their identities. While there is currently no evidence to suggest drug-drug interactions between PrEP and commonly used feminizing hormone regimens, community concerns about potential interactions may limit interest in and uptake of PrEP among trans women.

CONCLUSIONS

In scaling up PrEP for trans women, it is essential to engage trans communities, utilize trans-inclusive research and marketing strategies and identify and/or train healthcare providers to provide gender-affirming healthcare to trans women, including transition-related care such as hormone provision. PrEP implementation guidelines must consider and address trans women's unique barriers and facilitators to uptake and adherence.

PrEP implementation research in Africa: what is new?

INTRODUCTION

Of the two million new HIV infections in adults in 2014, 70% occurred in sub-Saharan Africa. Several African countries have already approved guidelines for pre-exposure prophylaxis (PrEP) for individuals at substantial risk of HIV as part of combination HIV prevention but key questions remain about how to identify and deliver PrEP to those at greatest need. Throughout the continent, individuals in sero-discordant relationships, and members of key populations (sex workers, men who have sex with men (MSM), transgender women and injection drug users) are likely to benefit from the availability of PrEP. In addition, adolescent girls and young women (AGYW) are at substantial risk in some parts of the continent. It has been estimated that at least three million individuals in Africa are likely to be eligible for PrEP according to WHO's criteria. Tens of demonstration projects are planned or underway across the continent among a range of countries, populations and delivery settings.

DISCUSSION

In each of the target populations, there are overarching issues related to (i) creating demand for PrEP, (ii) addressing supply-side issues and (iii) providing appropriate and tailored adherence support. Critical for creating demand for PrEP is the normalization of HIV prevention. Community-level interventions which engage opinion leaders as well as empowerment interventions for those at highest risk will be key. Critical to supply of PrEP is that services are accessible for all, including for stigmatized populations. Establishing accessible integrated services provides the opportunity to address other public health priorities including the unmet need for HIV testing, contraception and sexually transmitted infections treatment. National policies need to include minimum standards for training and quality assurance for PrEP implementation and to address supply chain issues. Adherence support needs to recognize that social and structural factors are likely to have an important influence. Combining interventions that build self-efficacy, empowerment and social cohesion, with evidence-based individualized adherence support for PrEP, are most likely to be effective.

CONCLUSIONS

Efficacy of tenfovir-based PrEP is proven but many issues related to implementation remain unclear. Here, we have summarized some of the important implementation questions that need to be assessed as PrEP is rolled out across Africa.

Implementation of pre-exposure prophylaxis for human immunodeficiency virus infection: progress and emerging issues in research and policy

BACKGROUND

In this article, we present recent evidence from studies focused on the implementation, effectiveness and cost-effectiveness of pre-exposure prophylaxis (PrEP) for HIV infection; discuss PrEP scale-up to date, including the observed levels of access and policy development; and elaborate on key emerging policy and research issues to consider for further scale-up, with a special focus on lower-middle income countries.

DISCUSSION

The 2015 WHO Early Release Guidelines for HIV Treatment and Prevention reflect both scientific evidence and new policy perspectives. Those guidelines present a timely challenge to health systems for the scaling up of not only treatment for every person living with HIV infection but also the offer of PrEP to those at substantial risk. Delivery and uptake of both universal antiretroviral therapy (ART) and PrEP will require nation-wide commitment and could reinvigorate health systems to develop more comprehensive "combination prevention" programmes and support wider testing linked to both treatments and other prevention options for populations at highest risk who are currently not accessing services. Various gaps in current health systems will need to be addressed to achieve strategic scale-up of PrEP, including developing prioritization strategies, strengthening drug regulations, determining cost and funding sources, training health providers, supporting user adherence and creating demand.

CONCLUSIONS

The initial steps in the scale-up of PrEP globally suggest feasibility, acceptability and likely impact. However, to prevent setbacks in less well-resourced settings, countries will need to anticipate and address challenges such as operational and health systems barriers, drug cost and regulatory policies, health providers' openness to prescribing PrEP to populations at substantial risk, demand and legal and human rights issues. Emerging problems will require creative solutions and will continue to illustrate the complexity of PrEP implementation.