Symptoms, Side Effects and Adherence in the iPrEx Open-Label Extension.
ABSTRACT: Blinded clinical trials have reported a modest and transient "start-up syndrome" with initiation of tenofovir-based pre-exposure prophylaxis (PrEP). We evaluate this phenomenon and its effect on adherence in an open-label PrEP study.In the iPrEx open-label extension (OLE) study, an 18-month open-label, multi-site PrEP cohort taking daily oral co-formulated tenofovir/emtricitabine, we examined the prevalence and duration of PrEP-associated symptoms and their effect on adherence, assessed by drug levels in dried blood spots tested monthly for the first 3 months.Symptom reports peaked within the first month, with 39% reporting potentially PrEP-related symptoms compared to 22% at baseline. Symptoms largely resolved to pre-PrEP levels by 3 months.Symptoms varied substantially in frequency by study site (range in 1-month symptoms: 11% to 70%). Nongastrointestinal (GI) symptoms were not associated with adherence (odds ratio [OR] = 1.2, 95% confidence interval [CI], .4-3.7); however, GI-associated symptoms in the first 4 weeks were inversely associated with adherence at 4 weeks (OR = 0.47, 95% CI, .23-.96). Reports of GI symptoms were associated with 7% (95% CI, 4%-11%) of suboptimal adherence in this cohort.PrEP-associated symptoms in the open-label setting occur in a minority of users and largely resolve within 3 months. GI symptoms are associated with a modest reduction in PrEP adherence, but good adherence is possible even in the presence of frequent symptom reports.Clinicaltrials.govNCT00458393.
Project description:Self-reported adherence to pre-exposure prophylaxis (PrEP) has limitations, raising interest in pharmacologic monitoring. Drug concentrations in hair and dried blood spots (DBS) are used to assess long-term-exposure; hair shipment/storage occurs at room temperature. The iPrEx Open Label Extension collected DBS routinely, with opt-in hair collection; concentrations were measured with liquid chromatography/tandem mass spectrometry. In 806 hair-DBS pairs, tenofovir (TFV) hair levels and TFV diphosphate (DP) in DBS were strongly correlated (Spearman coefficient r = 0.734; P < .001), as were hair TFV/DBS emtricitabine (FTC) triphosphate (TP) (r = 0.781; P < .001); hair FTC/DBS TFV-DP (r = 0.74; P < .001); hair FTC/DBS FTC-TP (r = 0.587; P < .001). Drug detectability was generally concordant by matrix. Hair TFV/FTC concentrations correlate strongly with DBS levels, which are predictive of PrEP outcomes.
Project description:BACKGROUND:Tenofovir disoproxil fumarate/emtricitabine preexposure prophylaxis (PrEP) is effective against HIV acquisition when taken as prescribed. Strategies that identify and intervene with those challenged by adherence to daily medication are needed. SETTING:PATH-PrEP was an open-label single-arm interventional cohort study conducted at 2 community-based clinical sites in Los Angeles, CA. METHODS:We enrolled self-identified men who have sex with men and transgender women ?18 years of age at an elevated risk of HIV acquisition. Participants received a postexposure prophylaxis (PEP)-based or PrEP-based HIV prevention package for at least 48 weeks. Plasma tenofovir levels from each PrEP visit assessed as below the limit of quantitation (<10 ng/mL) triggered increased adherence support. RESULTS:Three hundred one participants enrolled. Forty-eight-week retention in the PrEP cohort was 75.1%. Biomarker evidence of PrEP adherence consistent with ?4 doses per week at weeks 4, 12, 24, 36, and 48 was found in 83.1%, 83.4%, 75.7%, 71.6%, and 65.5% of participants, respectively; younger and African American participants were less likely to have protective drug levels. Most of those with suboptimal adherence had adherence improvement after brief intervention. One seroconversion occurred in a participant who discontinued PrEP. Nearly half (46.4%) of participants were diagnosed with at least 1 incident sexually transmitted infection during 48 weeks of study follow-up. CONCLUSIONS AND RELEVANCE:PrEP was acceptable and well tolerated in a diverse population of men who have sex with men in Los Angeles. A brief intervention triggered from biomarkers of poor adherence was associated with improved adherence. Drug level monitoring has the potential to allow targeting of additional adherence support to those struggling with daily tablet adherence.
Project description:BACKGROUND:HPTN 067 assessed the feasibility of daily and non-daily dosing of open-label emtricitabine/tenofovir disoproxil fumarate (FTC/TDF)-based pre-exposure prophylaxis (PrEP). METHODS:Factors associated with sex-related PrEP adherence were assessed among men who have sex with men (MSM) randomized to one of 3 PrEP dosing arms in HPTN 067 in New York City. Sex-related PrEP adherence was defined per protocol as at least 1 PrEP tablet taken within 4 days pre-sex and at least 1 additional PrEP tablet taken within 24 hours post-sex, assessed via electronic drug monitoring and weekly interviews. Demographic data and behavioral measures were evaluated for association with sex-related PrEP adherence. Logistic regression for clustered data was used to estimate the unadjusted and adjusted odds ratios. RESULTS:Of 176 randomized MSM participants, 59% were Black, 10% White, 25% Hispanic, and 6% other; median age was 31 years. In the multivariable analyses, higher sex-related PrEP adherence was significantly associated with daily dosing arm, older age, employment, and higher PrEP adherence behavioral skills. Lower sex-related PrEP adherence was significantly associated with identifying as Black or Hispanic (compared with White), opiate use, and reporting "I forgot" as an adherence barrier. CONCLUSIONS:This analysis identified populations of MSM who might benefit from additional support to optimize PrEP adherence, including those who are younger, unemployed, or opiate users. MSM with lower PrEP behavioral skills may benefit from targeted interventions. Further study is needed to assess racial and ethnic disparities in PrEP adherence, which may reflect broader social and economic inequalities not captured in this study.
Project description:Antiretroviral pre-exposure prophylaxis (PrEP) is a novel HIV prevention strategy for which adherence is a known determinant of efficacy. Blood concentrations of PrEP medications are one objective marker of adherence.In a placebo-controlled PrEP efficacy trial of tenofovir disoproxil fumarate (TDF) and TDF with emtricitabine (FTC/TDF) among 4747 African women and men with an HIV-infected partner, we measured plasma tenofovir concentrations from participants in the active PrEP arms: 29 HIV seroconverters (cases) and 196 randomly selected controls who remained uninfected.Among controls, 71% of visits had tenofovir concentrations >40 ng/mL, consistent with steady-state daily dosing, compared with 21% of cases at the visit HIV was first detected. Pill count data indicated that 96% of controls and 66% of cases had >80% adherence for these same visits. The estimated protective effect of PrEP against HIV, based on concentrations >40 ng/mL, was 88% (95% confidence interval: 60 to 96, P < 0.001) for individuals receiving TDF and 91% (95% confidence interval: 47 to 98, P = 0.008) for individuals receiving FTC/TDF. Controls had consistent patterns of PrEP concentrations during follow-up; among the 81% with concentrations >40 ng/mL at month 1, 75% maintained this concentration at month 12. Only 5 of 29 seroconverters seemed to be consistently adherent to PrEP. Tenofovir concentrations >40 ng/mL were associated with older age and shorter time on study; concentrations ≤40 ng/mL occurred more commonly when participants reported no sex with their HIV-infected partner.Plasma concentrations of tenofovir consistent with daily dosing were highly predictive of protection from HIV acquisition. Most of those who took PrEP seemed to have high and consistent adherence.
Project description:OBJECTIVES:Pregnancy is a time of increased HIV acquisition risk and pregnancy reduces concentrations of antiretrovirals used for treatment. We assessed whether pregnancy lowers concentrations of tenofovir (TFV) and tenofovir-diphosphate (TFV-DP) among HIV-uninfected women using oral preexposure prophylaxis (PrEP). METHODS:We analyzed data from an open-label PrEP study, comparing concentrations of TFV in plasma and TFV-DP in dried blood spots (DBS) among 37 pregnant women and 97 nonpregnant women. Analyses controlled for adherence from daily electronic monitoring. RESULTS:The average plasma concentration of TFV among pregnant women was 34.7?ng/ml with 22.2 average recorded doses over the prior month versus 86.5?ng/ml with 23.1 doses among nonpregnant women. After controlling for adherence, TFV concentrations were 58% lower among pregnant women, a statistically significant difference of -50.4?ng/ml (95% CI -68.3 to -32.5). The average TFV-DP concentration was 450.3?fmol/punch among pregnant women and 636.7?fmol/punch among nonpregnant women. This difference was not statistically significant after adjusting for adherence; however, among those with quantifiable TFV-DP, concentrations were 27% lower during pregnancy [-202?fmol/punch (95% CI -384 to -19)]. Among participants with samples before and during pregnancy, there were significant decreases during pregnancy, controlling for adherence: -28.1?ng/ml TFV (95% CI -52.3 to -4.0) and -289.2?fmol/punch TFV-DP (95% CI -439.0 to -139.3). CONCLUSION:Consistent with studies among HIV-infected women on ART, we found TFV and TFV-DP concentrations were lower during pregnancy. There is no established TFV concentration threshold to achieve HIV prevention. Additional pharmacokinetic studies and studies of PrEP efficacy in pregnancy are needed.
Project description:BACKGROUND:Daily preexposure prophylaxis (PrEP) is an effective HIV prevention strategy, but adherence is required for maximum benefit. To date, there are no empirically supported PrEP adherence interventions. This article describes the process of developing a PrEP adherence intervention and presents results on its impact on adherence. METHODS:The Partners PrEP Study was a placebo-controlled efficacy trial of daily oral tenofovir and emtricitabine/tenofovir PrEP among uninfected members of HIV-serodiscordant couples. An ancillary adherence study was conducted at 3 study sites in Uganda. Participants with <80% adherence as measured by unannounced pill count received an additional adherence counseling intervention based on Lifesteps, an evidence-based HIV treatment adherence intervention, based on principles of cognitive-behavioral theory. FINDINGS:Of the 1147 HIV-seronegative participants enrolled in the ancillary adherence study, 168 (14.6%) triggered the adherence intervention. Of participants triggering the intervention, 62% were men; median age was 32.5 years. The median number of adherence counseling sessions was 10. Mean adherence during the month before the intervention was 75.7% and increased significantly to 84.1% in the month after the first intervention session (P < 0.001). The most frequently endorsed adherence barriers at session 1 were travel and forgetting. INTERPRETATION:A PrEP adherence intervention was feasible in a clinical trial of PrEP in Uganda and PrEP adherence increased after the intervention. Future research should identify PrEP users with low adherence for enhanced adherence counseling and determine optimal implementation strategies for interventions to maximize PrEP effectiveness.
Project description:BACKGROUND:Adherence to pre-exposure prophylaxis (PrEP) is critical for efficacy. Antiretroviral concentrations are an objective measure of PrEP use and correlate with efficacy. Understanding patterns and correlates of drug detection can identify populations at risk for nonadherence and inform design of PrEP adherence interventions. METHODS:Blood antiretroviral concentrations were assessed among active arm participants in iPrEx, a randomized placebo-controlled trial of emtricitabine/tenofovir in men who have sex with men and transgender women in 6 countries. We evaluated rates and correlates of drug detection among a random sample of 470 participants at week 8 and a longitudinal cohort of 303 participants through 72 weeks of follow-up. RESULTS:Overall, 55% of participants (95% confidence interval: 49 to 60) tested at week 8 had drug detected. Drug detection was associated with older age and varied by study site. In longitudinal analysis, 31% never had drug detected, 30% always had drug detected, and 39% had an inconsistent pattern. Overall detection rates declined over time. Drug detection at some or all visits was associated with older age, indices of sexual risk, including condomless receptive anal sex, and responding "don't know" to a question about belief of PrEP efficacy (0-10 scale). CONCLUSIONS:Distinct patterns of study product use were identified, with a significant proportion demonstrating no drug detection at any visit. Research literacy may explain greater drug detection among populations having greater research experience, such as older men who have sex with men in the United States. Greater drug detection among those reporting highest risk sexual practices is expected to increase the impact and cost-effectiveness of PrEP.
Project description: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.
Project description:Oral and vaginal preparations of tenofovir as pre-exposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) infection have demonstrated variable efficacy in men and women prompting assessment of variation in drug concentration as an explanation. Knowledge of tenofovir concentration and its active form, tenofovir diphosphate, at the putative vaginal and rectal site of action and its relationship to concentrations at multiple other anatomic locations may provide key information for both interpreting PrEP study outcomes and planning future PrEP drug development.MTN-001 was designed to directly compare oral to vaginal steady-state tenofovir pharmacokinetics in blood, vaginal tissue, and vaginal and rectal fluid in a paired cross-over design.We enrolled 144 HIV-uninfected women at 4 US and 3 African clinical research sites in an open label, 3-period crossover study of three different daily tenofovir regimens, each for 6 weeks (oral 300 mg tenofovir disoproxil fumarate, vaginal 1% tenofovir gel [40 mg], or both). Serum concentrations after vaginal dosing were 56-fold lower than after oral dosing (p<0.001). Vaginal tissue tenofovir diphosphate was quantifiable in ?90% of women with vaginal dosing and only 19% of women with oral dosing. Vaginal tissue tenofovir diphosphate was ?130-fold higher with vaginal compared to oral dosing (p<0.001). Rectal fluid tenofovir concentrations in vaginal dosing periods were higher than concentrations measured in the oral only dosing period (p<0.03).Compared to oral dosing, vaginal dosing achieved much lower serum concentrations and much higher vaginal tissue concentrations. Even allowing for 100-fold concentration differences due to poor adherence or less frequent prescribed dosing, vaginal dosing of tenofovir should provide higher active site concentrations and theoretically greater PrEP efficacy than oral dosing; randomized topical dosing PrEP trials to the contrary indicates that factors beyond tenofovir's antiviral effect substantially influence PrEP efficacy.ClinicalTrials.gov NCT00592124.
Project description:BACKGROUND:We identified correlates of sex-related pre-exposure prophylaxis (PrEP) adherence in HPTN067/ADAPT, a phase 2, open-label feasibility study of daily and nondaily regimens of emtricitabine/tenofovir disoproxil fumarate (FTC/TDF)-based PrEP, among Thai men who have sex with men (MSM), and transgender women (TGW), Bangkok. METHODS:Participants were randomly assigned to one of three self-administered dosing regimens for 24 weeks: daily, time-driven, or event-driven. Demographic and behavioral information was obtained at screening. Pill-container opening was recorded with electronic dose monitoring, and self-reported information on PrEP use, sex events, and substance use was obtained during weekly interviews to confirm dose data. Sex-related PrEP adherence was calculated as the proportion of sex events covered by PrEP use (at least one tablet taken within 4 days before sex and at least one tablet taken within 24 hours after sex) to total sex events. We used multivariate modeling with sex event as the unit of analysis to evaluate correlates associated with sex-related PrEP adherence. RESULTS:Among 178 MSM and TGW, sex-related PrEP adherence was similar in the daily and time-driven arms (P = 0.79), both significantly greater than the event-driven arm (P = 0.02 compared to daily). Sex-related PrEP adherence by those reporting stimulant use (74.2%) was similar to those reporting other nonalcohol drug use (76.3%, P = 0.80), but lower than those reporting no substance use (84.6%, P = 0.04). In a multivariable model, randomization to the event-driven arm, a higher prestudy number of reported sex events, and use of stimulant drugs were associated with significantly lower sex-related PrEP adherence. CONCLUSION:Adherence was influenced by treatment schedule and adversely affected by nonalcoholic substance use. Regardless of these factors, Thai MSM and TGW maintained high adherence levels to oral PrEP dosing regimens and coverage of sexual exposures.