Delivery of TDF/FTC for Pre-exposure Prophylaxis to Prevent HIV-1 Acquisition in Young Adult Men Who Have Sex With Men and Transgender Women of Color Using a Urine Adherence Assay

A Systematic Review of Implementation Research on Determinants and Strategies of Effective HIV Interventions for Men Who Have Sex with Men in the United States

Men who have sex with men (MSM) are disproportionately affected by HIV, accounting for two-thirds of HIV cases in the United States despite representing ∼5% of the adult population. Delivery and use of existing and highly effective HIV prevention and treatment strategies remain suboptimal among MSM. To summarize the state of the science, we systematically review implementation determinants and strategies of HIV-related health interventions using implementation science frameworks. Research on implementation barriers has focused predominantly on characteristics of individual recipients (e.g., ethnicity, age, drug use) and less so on deliverers (e.g., nurses, physicians), with little focus on system-level factors. Similarly, most strategies target recipients to influence their uptake and adherence, rather than improving and supporting implementation systems. HIV implementation research is burgeoning; future research is needed to broaden the examination of barriers at the provider and system levels, as well as expand knowledge on how to match strategies to barriers-particularly to address stigma. Collaboration and coordination among federal, state, and local public health agencies; community-based organizations; health care providers; and scientists are important for successful implementation of HIV-related health innovations.

Demand creation and retention strategies for oral pre-exposure prophylaxis for HIV prevention among men who have sex with men and transgender women: a systematic review and meta-analysis

BACKGROUND

Men who have sex with men (MSM) and transgender women (TGW) have a disproportionately higher risk of human immunodeficiency virus (HIV) infection than other groups. Oral HIV pre-exposure prophylaxis (PrEP) is an effective prevention tool and should be offered to those at higher risk. Identifying demand creation strategies (DCS) and retention strategies (RS) to improve PrEP persistence is essential to control the HIV epidemic.

AIM

We aimed to identify the (DCS and RS with higher proportions among MSM and TGW.

METHODS

A systematic review and meta-analysis of prospective studies were conducted, with studies retrieved from five databases until November, 2022 following the Cochrane and PRISMA guidelines. The study protocol was registered in PROSPERO (CRD42022323220). The outcomes were DCS and RS for PrEP use among MSM and TGW. Strategies used for users enrolled in the PrEP-recruited (DCS) were classified as face-to-face (peer educator recruitment at social venues, nongovernmental organizations, and parties; direct referrals by health services; friends and/or sexual partners); online (chatbot or peer educator recruitment on social media [e.g., , Instagram or Facebook] or dating/hook-up apps [e.g., Grindr, Tinder, Badoo, and Scruff]); and mixed (face-to-face and online). RS was classified as provider counseling (face-to-face by a health professional; prevention of HIV risk counseling, distribution of condoms, lubricants, and testing for HIV or other sexually transmitted infections); online counseling (text messages, chatbots, telephone calls, social media, and peer educators); and mixed (all previous strategies). Subgroup analyses were conducted for each treatment strategy. Meta-analyses were performed using the R software version 4.2.1.

RESULTS

A total of 1, 129 studies were retrieved from the five databases. After eligibility, 46 studies were included. For MSM, most DCS and RS were online at 91% (95% CI: 0.85-0.97; I2=53%), and 83% (95% CI: 0.80-0.85; I2=17%) respectively. For TGW, mixed DCS and RS were the most frequent at85% (95% CI: 0.60-1.00; I2=91%) and online counseling at 84% (95% CI: 0.64-0.95) compared to other strategies.

CONCLUSION

Critical issues play. Pivotal role in increasing PrEP awareness among MSM and TGW, minimizing access gaps, and ensuring retention of PrEP services. Offering oral PrEP using online DCS and RS can reach and retain high numbers of MSM and TGW, and reduce HIV incidence in these populations.

Incidence and Prevalence of Hepatitis C Virus Among HIV-Negative Gay and Bisexual Men Using HIV Pre-exposure Prophylaxis (PrEP): A Systematic Review and Meta-analysis

Background

Gay and bisexual men using HIV pre-exposure prophylaxis (PrEP) are at increased risk for sexually transmissible infections. Hepatitis C virus (HCV) risk among PrEP users is less clear. We explored HCV prevalence and incidence among cohorts of gay and bisexual men using PrEP and sources of heterogeneity across studies.

Methods

This was a systematic review and meta-analysis of open-label PrEP studies to April 2022 reporting HCV prevalence at baseline or incidence during follow-up among gay and bisexual men using PrEP. Pooled prevalence and incidence estimates were calculated using random-effects meta-analysis, and subgroup analyses were performed by study- and country-level characteristics, including availability of HCV direct-acting antiviral (DAA) therapy at time of study.

Results

Twenty-four studies from 9 countries were included, with a total sample of 24 733 gay and bisexual men. Pooled HCV antibody baseline prevalence was 0.97% (95% CI, 0.63%-1.31%), and pooled HCV RNA baseline prevalence was 0.38% (95% CI, 0.19%-0.56%). Among 19 studies reporting HCV incidence, incidence ranged from 0.0 to 2.93/100 person-years (py); the pooled estimate was 0.83/100py (95% CI, 0.55-1.11). HCV incidence was higher in 12 studies that began follow-up before broad DAA availability (1.27/100py) than in 8 studies that began follow-up after broad DAA availability (0.34/100py) and higher in studies in Europe compared with North America and Australia.

Conclusions

Early reports of high HCV incidence among PrEP-using cohorts likely reflect enrollment of individuals based on specific risk-based eligibility criteria for smaller studies and enrollment before DAA scale-up. In contexts where both DAAs and PrEP have been implemented at scale, studies report lower HCV incidence. PrEP-specific HCV testing guidelines should be guided by local epidemiology.

Risk Factors Associated with Loss to Follow-up Among Transgender Women Receiving HIV Pre-exposure Prophylaxis in Chiang Mai province, Thailand

Although HIV pre-exposure prophylaxis (PrEP) is free in Thailand, many transgender women discontinue taking it after initiation. We determined the loss to follow-up (LTFU) rate of transgender women who initiated PrEP at the Mplus Foundation, Chiang Mai, Thailand, and identified associated risk factors using Cox proportional hazard models. Of 235 participants who initiated PrEP, 59 (55%) out of 108 remaining participants had reactive syphilis. The LTFU rate at 6 months was 38% (95% confidence interval [CI]: 29-48%). Multivariable analysis indicates that LTFU is independently associated with age ≥ 26 years old (adjusted hazard ratio [aHR] = 2.09; 95% CI: 1.06-4.14) and reactive syphilis (aHR = 1.98; 95% CI:1.01-3.88). Delayed appointment scheduling by the PrEP providers and the syphilis clinic was associated with transgender women having reactive syphilis, and the lockdown policy during the COVID-19 pandemic might have influenced them to discontinue PrEP and their subsequent LTFU.

Determinants of Pre-exposure Prophylaxis (PrEP) Implementation in Transgender Populations: A Qualitative Scoping Review

We conducted a scoping review of contextual factors impeding uptake and adherence to pre-exposure prophylaxis in transgender communities as an in-depth analysis of the transgender population within a previously published systematic review. Using a machine learning screening process, title and abstract screening, and full-text review, the initial systematic review identified 353 articles for analysis. These articles were peer-reviewed, implementation-related studies of PrEP in the U.S. published after 2000. Twenty-two articles were identified in this search as transgender related. An additional eleven articles were identified through citations of these twenty-two articles, resulting in thirty-three articles in the current analysis. These thirty-three articles were qualitatively coded in NVivo using adapted constructs from the Consolidated Framework for Implementation Research as individual codes. Codes were thematically assessed. We point to barriers of implementing PrEP, including lack of intentional dissemination efforts and patience assistance, structural factors, including sex work, racism, and access to gender affirming health care, and lack of provider training. Finally, over 60% of articles lumped cisgender men who have sex with men with trans women. Such articles included sub-samples of transgender individuals that were not representative. We point to areas of growth for the field in this regard.

Impact of daily, oral pre-exposure prophylaxis on the risk of bacterial sexually transmitted infections among cisgender women: a systematic review and narrative synthesis

Background: There are concerns that the use of pre-exposure prophylaxis (PrEP) may result in an increased incidence of sexually transmitted infections (STIs). Evidence for this is mixed and has mostly been based on reviews focussed on gay and bisexual men and transgender women, while none have summarised evidence in cisgender women. Methods: We conducted a systematic review to explore whether daily, oral PrEP use is associated with changes in bacterial STI occurrence (diagnoses or self-reported) and/or risk among HIV seronegative cisgender women (ciswomen). The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. Results: We included 11 full text articles in a narrative synthesis, with the studies published between 2012 and 2021. The studies were mostly based in Africa (n=7, 63.6%) and reported on 3168 ciswomen using PrEP aged 16-56 years. Studies had marked differences in variables, including measurements and definitions (e.g., STI type) and limited data available looking specifically at ciswomen, principally in studies with both male and female participants. The limited evidence suggests that PrEP use is not associated with increased STI rates in ciswomen generally; however, adolescent girls and young women in Sub Saharan Africa have a higher prevalence of bacterial STIs prior to PrEP initiation, compared to adult ciswomen and female sex workers. Conclusions: We suggest future PrEP research make efforts to include ciswomen as study participants and report stratified results by gender identity to provide adequate data to inform guidelines for PrEP implementation. PROSPERO registration: CRD42019130438.

Discontinuation, suboptimal adherence, and reinitiation of oral HIV pre-exposure prophylaxis: a global systematic review and meta-analysis

BACKGROUND

Poor adherence to oral HIV pre-exposure prophylaxis (PrEP) diminishes its clinical and public health benefits. This study synthesises evidence regarding discontinuation, adherence, and reinitiation of PrEP among geographically diverse PrEP users.

METHODS

We did a systematic review and meta-analysis evaluating studies published in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials from inception to Dec 18, 2020. We included longitudinal studies that presented data for PrEP discontinuation, defined as investigator-reported loss to follow-up or participant self-reported PrEP stoppage. Data were extracted from published reports and assessed for risk of bias. We used a random-effects meta-analysis to pool estimates of discontinuation and I2 and τ2 to evaluate heterogeneity. This study is registered with PROSPERO, CRD42020155675.

FINDINGS

We identified 4129 records, of which 59 articles were included (n=43 917 participants). 41·0% (95% CI 18·8-63·5) of participants discontinued PrEP within 6 months, with the highest rates in observational studies. The discontinuation rate in sub-Saharan Africa (47·5%, 95% CI: 29·4-66·4%) was higher than in other regions (p<0·001). Discontinuation rates were lower in studies with adherence interventions than in those without (24·7% vs 36·7%, p=0·015). Gay or bisexual men who have sex with men and transgender women offered daily or non-daily dosing options had lower discontinuation rates than those offered daily dosing alone (21·6% vs 31·5%; p<0·001). The pooled suboptimal adherence within 6 months was 37·7% (95% CI 8·4-66·9). Among people who discontinued PrEP, 47·3% (95% CI 31·5-63·2) reinitiated PrEP within 1 year of PrEP initiation. The included studies had poor quality in terms of study design, with a moderate risk of bias.

INTERPRETATION

Strategies to encourage reinitiating PrEP for new or persistent risk should be a focus of future PrEP implementation strategies.

FUNDING

National Institutes of Health and Nature Science Foundation of China.

Understanding Retention in Pre-Exposure Prophylaxis Care in the South: Insights from an Academic HIV Prevention Clinic

HIV pre-exposure prophylaxis (PrEP) is poorly utilized in the southern United States. We examined PrEP retention in care and sexually transmitted infections (STIs) through a retrospective review of the Duke University PrEP Clinic from January 1, 2015 to October 15, 2019. We evaluated short-term (3 months), long-term (additional 8–12 months), and longitudinal retention in care in our clinic. Adjusted odds ratios (aOR) were generated to explore demographics associated with retention. Kaplan–Meier curves were generated to view retention longitudinally. STIs were examined at baseline (1 year before initial PrEP visit) and while retained in care. Of a total of 255 patients; 88% were men, 37% were black, and 73% were men who have sex with men (MSM). Short- and long-term retention in care were met by 130/237 (55%) and 80/217 (37%) patients, respectively. MSM were more likely to be retained in the short term (aOR = 5.22, 95% confidence interval [CI] = 1.57–17.32). Self-referred patients were more likely to be retained in the long term (aOR = 2.18, 95% CI = 1.12–4.23). Uninsured patients were less likely to be retained in the long term (aOR = 0.32, 95% CI = 0.11–0.91). STI diagnoses include 42 infections at baseline and 69 infections during follow-up. STI diagnosed while in PrEP care was associated with longer retention in care over time. Patients discontinue PrEP care over time and STIs were frequently encountered. Additional studies are needed to determine the best way to retain patients in HIV preventative care.

Impact of daily, oral pre-exposure prophylaxis on the risk of bacterial sexually transmitted infections among cisgender women: a systematic review and narrative synthesis

Background: There are concerns that the use of pre-exposure prophylaxis (PrEP) may result in an increased incidence of sexually transmitted infections (STIs). Evidence for this is mixed and has mostly been based on reviews focussed on gay and bisexual men and transgender women, while none have summarised evidence in cisgender women. Methods: We conducted a systematic review to explore whether daily, oral PrEP use is associated with changes in bacterial STI occurrence (diagnoses or self-reported) and/or risk among HIV seronegative cisgender women (ciswomen). The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool. Results: We included 11 full text articles in a narrative synthesis, with the studies published between 2012 and 2021. The studies were mostly based in Africa (n=7, 63.6%) and reported on 3168 ciswomen using PrEP aged 16-56 years. Studies had marked differences in variables, including measurements and definitions (e.g., STI type) and limited data available looking specifically at ciswomen, principally in studies with both male and female participants. The limited evidence suggests that PrEP use is not associated with increased STI rates in ciswomen generally; however, adolescent girls and young women in Sub Saharan Africa have a higher prevalence of bacterial STIs prior to PrEP initiation, compared to adult ciswomen and female sex workers. Conclusions: We suggest future PrEP research make efforts to include ciswomen as study participants and report stratified results by gender identity to provide adequate data to inform guidelines for PrEP implementation. PROSPERO registration: CRD42019130438.

Adherence to Pre-Exposure Prophylaxis in Adolescents and Young Adults: A Systematic Review and Meta-Analysis

This meta-analysis synthesized the proportion of adolescents and young adults (AYAs) who are adherent to pre-exposure prophylaxis (PrEP) and factors moderating adherence. A systematic search was conducted of studies published through May 2020 using PubMed, PsycInfo, Cochrane, EMBASE, and CINAHL. Included studies reported the proportion of AYAs (mean age ≤ 29 years) who were PrEP adherent. PrEP adherence was meta-analyzed using random-effects models. Secondary analyses evaluated potential moderating variables. A total of 41 individual samples, from 29 studies, of 8,679 AYA (weighted average age = 23.8 years) were synthesized. The proportion of AYA who met study-defined thresholds for PrEP adherence was .64 (95% confidence interval .57-.71) across studies. Subgroup analyses revealed that adherence was lower in young cisgender women (.46) than young men who have sex with men (.65) and serodiscordant heterosexual couples (.98). Adherence was higher in studies initiated after 2012 (.70) than earlier studies (.47). No differences based on participant age, country, or strategies to promote adherence were found. Across published studies to date, 64% of AYA demonstrate adequate PrEP adherence. Findings can be used to guide PrEP adherence interventions and also provide directions for future research on PrEP among AYA.

PrEP uptake, persistence, adherence, and effect of retrospective drug level feedback on PrEP adherence among young women in southern Africa: Results from HPTN 082, a randomized controlled trial

BACKGROUND

Pre-exposure prophylaxis (PrEP) is highly effective and an important prevention tool for African adolescent girls and young women (AGYW), but adherence and persistence are challenging. PrEP adherence support strategies for African AGYW were studied in an implementation study.

METHODS AND FINDINGS

HIV Prevention Trials Network (HPTN) 082 was conducted in Cape Town, Johannesburg (South Africa) and Harare (Zimbabwe) from October 2016 to October 2018 to evaluate PrEP uptake, persistence, and the effect of drug level feedback on adherence. Sexually active HIV-negative women ages 16-25 were offered PrEP and followed for 12 months; women who accepted PrEP were randomized to standard adherence support (counseling, 2-way SMS, and adherence clubs) or enhanced adherence support with adherence feedback from intracellular tenofovir-diphosphate (TFV-DP) levels in dried blood spots (DBS). PrEP uptake, persistence through 12 months (no PrEP hold or missed visits), and adherence were assessed. The primary outcome was high adherence (TFV-DP ≥700 fmol/punch) at 6 months, compared by study arm. Of 451 women enrolled, median age was 21 years, and 39% had curable sexually transmitted infections (STIs). Most (95%) started PrEP, of whom 55% had uninterrupted PrEP refills through 12 months. Of those with DBS, 84% had detectable TFV-DP levels at month 3, 57% at month 6, and 31% at month 12. At 6 months, 36/179 (21%) of AGYW in the enhanced arm had high adherence and 40/184 (22%) in the standard adherence support arm (adjusted odds ratio [OR] of 0.92; 95% confidence interval [CI] 0.55, 1.34; p = 0.76). Four women acquired HIV (incidence 1.0/100 person-years), with low or undetectable TFV-DP levels at or prior to seroconversion, and none of whom had tenofovir or emtricitabine resistance mutations. The study had limited power to detect a modest effect of drug level feedback on adherence, and there was limited awareness of PrEP at the time the study was conducted.

CONCLUSIONS

In this study, PrEP initiation was high, over half of study participants persisted with PrEP through month 12, and the majority of young African women had detectable TFV-DP levels through month 6 with one-fifth having high adherence. Drug level feedback in the first 3 months of PrEP use did not increase the proportion with high adherence at month 6. HIV incidence was 1% in this cohort with 39% prevalence of curable STIs and moderate PrEP adherence. Strategies to support PrEP use and less adherence-dependent formulations are needed for this population.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02732730.

Brief Report: Urine Emtricitabine and Tenofovir Concentrations Provide Markers of Recent Antiretroviral Drug Exposure Among HIV-Negative Men Who Have Sex With Men

BACKGROUND

Urine provides a minimally invasive specimen that may allow for development of rapid tests to detect antiretroviral drugs and provide opportunities to improve individual adherence. This study sought to determine whether urine could provide a biomarker of adherence for currently approved pre-exposure prophylaxis and HIV treatment regimens.

METHODS

Urine and blood were collected from 34 HIV-negative men who have sex with men aged 18-49 years, enrolled in a clinical trial comparing 2 antiretroviral regimens. Specimens were collected 4 and 24 hours after a single oral dose of tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) (n = 10) or tenofovir alafenamide (TAF)/FTC/cobicistat (COBI)/elvitegravir (EVG) (n = 8), or after 4 and 10 days of daily oral TDF/FTC (n = 9) or TAF/FTC/COBI/EVG (n = 7). Tenofovir (TFV), FTC, and EVG were measured by high-performance liquid chromatography-mass spectrometry.

RESULTS

Median urine FTC concentrations at 4 and 24 hours were similar between men receiving TDF/FTC (4 hours 147 µg/mL; 24 hours 10 µg/mL) and men receiving TAF/FTC/COBI/EVG (4 hours 333 µg/mL, P = 0.173; 24 hours 13 µg/mL, P = 0.681). Median urine TFV concentrations were lower among men receiving TAF/FTC/COBI/EVG (4 hours 1.2 µg/mL; 24 hours 0.8 µg/mL) compared with men receiving TDF/FTC (4 hours 17 µg/mL, P < 0.001; 24 hours 7 µg/mL, P = 0.001). Urine TFV concentrations remained reduced among men receiving TAF/FTC/COBI/EVG compared with men receiving TDF/FTC after daily dosing. EVG was not consistently measurable in urine.

CONCLUSIONS

High urine FTC and TFV concentrations could provide an indication of adherence to daily oral dosing with TDF or TAF-based regimens used for treatment and prevention.

Urine Tenofovir Concentrations Correlate With Plasma and Relate to Tenofovir Disoproxil Fumarate Adherence: A Randomized, Directly Observed Pharmacokinetic Trial (TARGET Study)

BACKGROUND

Direct measurement of tenofovir (TFV) in urine could be an objective measure to monitor adherence to preexposure prophylaxis (PrEP) or TFV-based antiretroviral therapy (ART).

METHODS

We conducted a 3-arm randomized, pharmacokinetic study of tenofovir disoproxil fumarate (TDF) 300 mg/emtricitabine (FTC) 200 mg among adults living with human immunodeficiency virus. Participants were randomized to receive controlled TDF/FTC dosing as (1) "perfect" adherence (daily); (2) "moderate" adherence (4 doses/week); or (3) "low" adherence (2 doses/week). We obtained trough spot urine and plasma samples during a 6-week directly observed therapy period and a 4-week washout period. TFV concentrations were compared between adherence arms using 1-way analysis of variance.

RESULTS

Among 28 participants, the median age was 33 years and 16 (57%) were male. Correlation between TFV plasma and urine concentrations was strong (ρ = 0.78; P < .0001). Median (interquartile range) steady-state trough TFV concentrations (ng/mL) for perfect, moderate, and low TDF adherence were 41 (26-52), 16 (14-19), and 4 (3-5) in plasma; and 6480 (3940-14 300), 3405 (2210-5020), and 448 (228-675) in urine. Trough TFV concentrations at steady state were significantly different between the 3 adherence arms for plasma (P < .0001) and urine (P = .0002). Following drug cessation, TFV concentrations persisted longer in urine than plasma samples. Washout urine TFV concentrations and time to undetectable concentrations did not differ between the 3 randomized adherence groups.

CONCLUSIONS

Urine TFV concentrations can inform interpretation of novel point-of-care urine-based TFV assays to assess recent TDF adherence.

CLINICAL TRIALS REGISTRATION

NCT03012607

Urine Assay to Measure Tenofovir Concentrations in Patients Taking Tenofovir Alafenamide

Background: HIV pre-exposure prophylaxis (PrEP) with tenofovir/emtricitabine is effective when taken daily. Previously, we developed a urine assay capable of detecting the prodrug tenofovir (TFV) in patients taking tenofovir disoproxil fumarate (TDF)-based PrEP. However, tenofovir alafenamide (TAF) has replaced TDF due to its different safety profile for HIV treatment and was recently approved as PrEP. Given the need to ensure the aforementioned assay remains available for the purpose of objective adherence monitoring, it is critical to ensure its accuracy for detecting TFV in patients taking TAF. Methods: Blood and urine samples were collected from 3 cohorts of patients: (1) 10 participants living with HIV (PLWH) with suppressed virus on a TAF-based regimen, (2) 10 HIV-participants administered 1 dose of TAF/FTC followed by urine and plasma sampling for 7 days starting 1-3 h post-dose, and (3) 10 HIV-participants administered 7 doses of TAF/FTC followed by urine and plasma sampling for 10 days starting 1-3 h after the last dose. Samples were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with high sensitivity and specificity for TFV. HIV-samples were compared to a historical cohort administered one dose of TDF/FTC. Results: PLWH were 90% male, 40% African American, and 10% Hispanic (mean age = 57 y; SD 8.88 y). HIV-participants were 55% male and 70% Caucasian (mean age = 31.6 y; SD 7.70 y). Samples from PLWH demonstrated TFV concentrations 2 logs higher in urine than plasma (1,000 ng/mL vs ±10 ng/mL) at the time of collection. Urine samples following a single dose of TAF in HIV-participants yielded TFV concentrations ranging from 100 to 1,000 ng/mL 1-3 h post-dose and remained >100 ng/mL for 6 days in 8 of 10 participants. Urine samples collected after 7 consecutive doses of TAF yielded TFV concentrations >1,000 ng/mL 1-3 h after dosing discontinuation, with TFV concentrations >1,00 ng/mL 7 days post discontinuation in 8 of 10 participants. Urine TFV concentrations following TAF administration were comparable to those from a historical cohort administered TDF/FTC. Plasma TFV concentrations were low(±10 ng/mL) in both HIV-cohorts at all time points. Conclusions: TFV persists in urine at detectable concentrations in participants taking TAF/FTC for at least 7 days despite largely undetectable plasma concentrations, with urine TFV concentrations comparable to patients taking TDF/FTC. This study demonstrates the ability of a urine TFV assay to measure recent TAF adherence.

Brief Report: Validation of a Urine Tenofovir Immunoassay for Adherence Monitoring to PrEP and ART and Establishing the Cutoff for a Point-of-Care Test

BACKGROUND

Current pharmacologic adherence monitoring for antiretrovirals involves expensive, labor-intensive liquid chromatography/tandem mass spectrometry (LC-MS/MS)-based methods. Antibody-based assays can monitor and support adherence in real time. We developed a tenofovir (TFV)-based immunoassay and further validated it in a directly observed therapy (DOT) study.

DESIGN

Pharmacologic DOT study of TFV disoproxil fumarate (TDF)/emtricitabine (FTC) administered to HIV-noninfected volunteers.

METHODS

The TARGET study provided directly observed TDF 300 mg/FTC 200 mg 7 (high adherence), 4 (moderate), and 2 doses/week (low) to 30 volunteers (10/group) in Thailand, collecting a total of 637 urine samples over 6 weeks of administration and during washout. ELISA measured urine TFV levels by the immunoassay and LC-MS/MS-based concentrations served as the gold standard. A mixed-effects regression model evaluated cutoffs for a point-of-care assay. Performance characteristics of the immunoassay were compared with LC-MS/MS at a chosen cutoff.

RESULTS

Median TFV levels were 12,000 ng/mL by the immunoassay 1 day after dosing; 5000 ng/mL 2 days after dosing; 1500 ng/mL 3 days after dosing; and below the lower limit of quantification thereafter (≥4 days). An immunoassay cutoff of 1500 ng/mL accurately classified 98% of patients who took a dose 24 hours ago as adherent. The specificity and sensitivity of the immunoassay compared with LC-MS/MS at the 1500 ng/mL cutoff were 99% and 94%; the correlation between TFV levels by the 2 assays was high (0.92, P < 0.00001).

CONCLUSIONS

We have developed a novel TFV immunoassay that is highly specific, sensitive, and correlates strongly with LC-MS/MS measurements in a large DOT study. Adherence benchmarks from this DOT study will guide the development of a low-cost rapid point-of-care test for pre-exposure prophylaxis and antiretroviral treatment adherence monitoring and interventions.

Global Epidemiologic Characteristics of Sexually Transmitted Infections Among Individuals Using Preexposure Prophylaxis for the Prevention of HIV Infection: A Systematic Review and Meta-analysis

IMPORTANCE

Despite a global increase in sexually transmitted infections (STIs), there is limited focus and investment in STI management within HIV programs, in which risks for STIs are likely to be elevated.

OBJECTIVE

To estimate the prevalence of STIs at initiation of HIV preexposure prophylaxis (PrEP; emtricitabine and tenofovir disoproxil fumarate) and the incidence of STIs during PrEP use.

DATA SOURCES

Nine databases were searched up to November 20, 2018, without language restrictions. The implementers of PrEP were also approached for additional unpublished data.

STUDY SELECTION

Studies reporting STI prevalence and/or incidence among PrEP users were included.

DATA EXTRACTION AND SYNTHESIS

Data were extracted independently by at least 2 reviewers. The methodological quality of studies was assessed using the Joanna Briggs Institute critical assessment tool for prevalence and incidence studies. Random-effects meta-analysis was performed.

MAIN OUTCOMES AND MEASURES

Pooled STI prevalence (ie, within 3 months of PrEP initiation) and STI incidence (ie, during PrEP use, after 3 months).

RESULTS

Of the 3325 articles identified, 88 were included (71 published and 17 unpublished). Data came from 26 countries; 62 studies (70%) were from high-income countries, and 58 studies (66%) were from programs only for men who have sex with men. In studies reporting a composite outcome of chlamydia, gonorrhea, and early syphilis, the pooled prevalence was 23.9% (95% CI, 18.6%-29.6%) before starting PrEP. The prevalence of the STI pathogen by anatomical site showed that prevalence was highest in the anorectum (chlamydia, 8.5% [95% CI, 6.3%-11.0%]; gonorrhea, 9.3% [95% CI, 4.7%-15.2%]) compared with genital sites (chlamydia, 4.0% [95% CI, 2.0%-6.6%]; gonorrhea, 2.1% [95% CI, 0.9%-3.7%]) and oropharyngeal sites (chlamydia, 2.4% [95% CI, 0.9%-4.5%]; gonorrhea, 4.9% [95% CI, 1.9%-9.1%]). The pooled incidence of studies reporting the composite outcome of chlamydia, gonorrhea, and early syphilis was 72.2 per 100 person-years (95% CI, 60.5-86.2 per 100 person-years).

CONCLUSIONS AND RELEVANCE

Given the high burden of STIs among individuals initiating PrEP as well as persistent users of PrEP, this study highlights the need for active integration of HIV and STI services for an at-risk and underserved population.

Barriers and Facilitators of PrEP Adherence for Young Men and Transgender Women of Color

We aimed to discover barriers and facilitators of HIV pre-exposure prophylaxis (PrEP) adherence in young men and transgender women of color who have sex with men (YMSM/TW). Short-term and sustained adherence were measured by urine tenofovir concentration and pharmacy refills, respectively. Optimal adherence was defined as having both urine tenofovir concentration consistent with dose ingestion within 48 h and pharmacy refills consistent with ≥ 4 doses per week use. Participants completed semi-structured interviews exploring adherence barriers and facilitators. Participants (n = 31) were primarily African-American (68%), mean age 22 years (SD: 1.8), and 48% had optimal adherence. Adherence barriers included stigma, health systems inaccessibility, side effects, competing stressors, and low HIV risk perception. Facilitators included social support, health system accessibility, reminders/routines, high HIV risk perception, and personal agency. Our findings identify targets for intervention to improve PrEP adherence in these populations, including augmenting health activation and improving accuracy of HIV risk perception.

Brief Report: Short-Term Adherence Marker to PrEP Predicts Future Nonretention in a Large PrEP Demo Project: Implications for Point-of-Care Adherence Testing

BACKGROUND

Objective adherence metrics for tenofovir (TFV) disoproxil fumarate/emtricitabine (FTC)-based pre-exposure prophylaxis (PrEP) were critical for interpretation of efficacy in PrEP clinical trials, and there is increasing interest in using drug levels to tailor interventions for reengagement and adherence. Point-of-care immunoassays for TFV, which examine short-term adherence, are in development. However, the ability of poor short-term and long-term adherence to predict future PrEP nonretention is unknown.

SETTING

Secondary data analysis of a large, prospective multi-site U.S. PrEP demonstration project.

METHODS

An adjusted Cox-proportional hazards model examined the relationship of dried blood spot (DBS) levels of FTC-triphosphate (FTC-TP) or TFV-diphosphate (TFV-DP), measures of short-term and long-term PrEP adherence, respectively, with future study nonretention.

RESULTS

Overall, 294 individuals (median age 33 years) contributed drug levels within the U.S. PrEP demonstration project. By the end of study, 27% were lost to follow-up, 25% had at least one undetectable FTC-TP level indicating poor short-term adherence, and 29% had a drug level indicating suboptimal long-term adherence (TFV-DP <700 fmol/punch). The strongest factor associated with future study nonretention using a binary drug-level cut-off was an undetectable DBS FTC-TP level (adjusted hazard ratio 6.3; 95% confidence interval 3.8 to 10.2). The suboptimal long-term adherence based on low DBS TFV-DP levels was also associated with nonretention (adjusted hazard ratio 4.3; 95% confidence interval: 2.4 to 7.6).

CONCLUSIONS

Both short- and long-term metrics of PrEP adherence are strongly associated with future loss to follow-up in a U.S. demonstration project study. Short-term metrics of adherence, once available at the point-of-care, could be used to direct real-time tailored retention and adherence interventions.

Low tenofovir level in urine by a novel immunoassay is associated with seroconversion in a preexposure prophylaxis demonstration project

OBJECTIVE

We examined the relationship between urine tenofovir (TFV) levels measured with a novel immunoassay, which permits point-of-care testing, with HIV seroconversion and objective adherence metrics in a large preexposure prophylaxis (PrEP) demonstration project.

DESIGN

Secondary analysis of stored specimens from an open-label PrEP cohort study.

METHODS

We examined the association between undetectable urine TFV levels and HIV seroconversion in iPrEx open-label extension using generalized estimating equations. We examined rank correlations between levels of TFV and emtricitabine in urine, dried blood spots (DBS), and hair and determined the sensitivity and specificity of undetectable urine TFV for predicting dosing cut-offs in DBS.

RESULTS

The median urinary TFV level was 15 000 ng/ml in those who remained HIV-negative (n = 105; interquartile range: 1000-45 000); 5500 in those who eventually seroconverted (n = 11; interquartile range: 1000-12 500); and all were undetectable at seroconversion (n = 9; P < 0.001). Decreasing strata of urine TFV levels were associated with future HIV seroconversion (P = 0.03). An undetectable urine TFV was 100% sensitive and 81% specific when compared with an undetectable DBS TFV-diphosphate level and 69% sensitive, but 94% specific when compared with low adherence by DBS (<2 doses/week).

CONCLUSION

Urine TFV detection by a novel antibody-based assay was associated with protection from HIV acquisition among individuals on PrEP. Urine TFV levels were correlated with hair and DBS levels and undetectable urine TFV was 100% sensitive in detecting nonadherence. By implementing the immunoassay into a point-of-care strip test, PrEP nonadherence could be detected in real-time, allowing rapid intervention.

Incidence of sexually transmitted infections in men who have sex with men and who are at substantial risk of HIV infection - A meta-analysis of data from trials and observational studies of HIV pre-exposure prophylaxis

Background

Men who have sex with men (MSM) and who engage in condomless anal intercourse with casual partners are at high risk of acquiring sexually transmitted infections (STIs), but reliable epidemiological data are scarce. Studies on HIV pre-exposure prophylaxis (PrEP) enrol MSM who indicate that they engage in behaviour that puts them at high risk of acquiring HIV. Because they also screen for STIs at regular intervals, these studies may serve as a valuable source to estimate incidence rates of STIs in this subpopulation of MSM.

Methods

We systematically searched for trials and observational studies of PrEP in MSM that reported data on the incidence of STIs during the study period. Incidence rates were calculated as events per 100 person-years (py) with 95% confidence intervals (CI). Data from individual studies were pooled building subgroups along study types and geography. We performed sensitivity analyses, including data only from studies that met pre-defined quality criteria.

Results

Twenty-four publications on 20 studies were included. The majority of studies reported that sexual behaviour and/or STI incidence remained stable or decreased during the study period. For syphilis, incidence rates ranged from 1.8/100py to 14.9/100py, the pooled estimate was 9.1/100py (95%-CI: 7.7–10.9). Incidence rates for gonorrhoea and chlamydia of any site ranged from 13.3/100py to 43.0/100py and 15.1/100py to 48.5/100py, respectively. Considering only studies that met the criteria for sensitivity analysis yielded pooled estimates of 39.6/100py (95%-CI: 32.9–47.6) and 41.8/100py (95%-CI: 33.9–51.5), respectively. The overall estimate for hepatitis C incidence was 1.3/100py (95%-CI: 1.0–1.8).

Conclusions

Despite partly heterogeneous results, the data depict high incidence rates of STIs among MSM who engage in higher-risk sexual behaviours such as condomless sex with casual partners. This subpopulation of MSM requires access to STI screening at close intervals. By offering access to structures that provide regular STI monitoring and prompt treatment, PrEP may not only decrease HIV incidence but also have beneficial effects in decreasing the burden of STIs.