Tenofovir Diphosphate in Dried Blood Spots in Pregnant and Postpartum Women With HIV in Kenya: A Novel Approach to Measuring Peripartum Adherence.

BACKGROUND: Adherence to antiretroviral therapy (ART) among pregnant and postpartum women with HIV (PWLWH) is critical to promote maternal health and prevent HIV transmission. Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) is an objective assessment of cumulative ART adherence that has not been fully assessed in PWLWH. SETTING: Southwestern Kenya. METHODS: PWLWH receiving tenofovir disoproxil fumarate-based ART from 24 health facilities provided DBS samples at 3 time points [pregnancy/early postpartum (PP), 6 months PP, and 9-12 months PP]. Thresholds for daily adherence were defined as TFV-DP in DBS ≥650 fmol/punch in pregnancy and ≥950 PP. Descriptive analysis is presented. Cluster adjusted χ2 and t-tests were used to test for association with clinical and demographic factors. RESULTS: A total of 419 DBS samples were collected from 150 PWLWH. Median TFV-DP in DBS was lowest, 552 fmol/punch [interquartile range (IQR), 395-759] in pregnancy and declined over time [914 (IQR, 644-1176) fmol/punch; early PP; 838 (IQR, 613-1063) fmol/punch 6 months PP; and 785 (IQR, 510-1009) fmol/punch 9-12 months; P < 0.001]. Only 42% of samples in pregnancy and 38.5% of samples in PP met thresholds for daily adherence. Clinical or demographic factors were not associated with suboptimal adherence levels. CONCLUSION: Cumulative ART exposure in PWLWH, quantified by TFV-DP in DBS, demonstrated a stepwise decrease (ie, adherence) PP. Most women demonstrated less than daily adherence throughout the peripartum period. Use of TFV-DP in DBS as a measure of cumulative ART adherence could help optimize health outcomes in PWLWH and their infants.

Feasibility and Successful Enrollment in a Proof-of-Concept HIV Prevention Trial of VRC01, a Broadly Neutralizing HIV-1 Monoclonal Antibody.

BACKGROUND: The Antibody-Mediated Prevention trials (HVTN 704/HPTN 085 and HVTN 703/HPTN 081) are the first efficacy trials to evaluate whether VRC01, a broadly neutralizing monoclonal antibody targeting the CD4-binding site of the HIV envelope protein, prevents sexual transmission of HIV-1. HVTN 704/HPTN 085 enrolled 2701 cisgender men and transgender (TG) individuals who have sex with men at 26 sites in Brazil, Peru, Switzerland, and the United States. METHODS: Participants were recruited and retained through early, extensive community engagement. Eligible participants were randomized 1:1:1 to 10 mg/kg or 30 mg/kg of VRC01 or saline placebo. Visits occurred monthly, with intravenous (IV) infusions every 8 weeks over 2 years, for a total of 10 infusions. Participants were followed for 104 weeks after first infusion. RESULTS: The median HVTN 704/HPTN 085 participant age was 28 years; 99% were assigned male sex; 90% identified as cisgender men, 5% as TG women and the remaining as other genders. Thirty-two percent were White, 15% Black, and 57% Hispanic/Latinx. Twenty-eight percent had a sexually transmitted infection at enrollment. More than 23,000 infusions were administered with no serious IV administration complications. Overall, retention and adherence to the study schedule exceeded 90%, and the dropout rate was below 10% annually (7.3 per 100 person-years) through week 80, the last visit for the primary end point. CONCLUSIONS: HVTN 704/HPTN 085 exceeded accrual and retention expectations. With exceptional safety of IV administration and operational feasibility, it paves the way for future large-scale monoclonal antibody trials for HIV prevention and/or treatment.

Lower Cumulative Antiretroviral Exposure in People Living With HIV and Diabetes Mellitus.

OBJECTIVE: People living with HIV (PLWH) are living longer and developing more non-AIDS comorbidities, which negatively impact antiretroviral therapy (ART) adherence. Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) is a novel pharmacologic measure of cumulative ART adherence that is predictive of viral suppression and future viremia. However, the relationship between non-AIDS comorbidities and this adherence measure is unknown. We aimed to evaluate the association between 3 non-AIDS comorbidities (diabetes mellitus (DM), hypertension, and hyperlipidemia) and TFV-DP in DBS in PLWH. METHODS: Blood for TFV-DP in DBS and HIV viral load was prospectively collected from PLWH on tenofovir disoproxil fumarate for up to 3 times over 48 weeks. Non-AIDS comorbidities were recorded. Mixed effect multivariable linear regression models were used to estimate the changes in TFV-DP concentrations in DBS according to the presence of comorbidities and to estimate the percent differences in TFV-DP concentrations between these groups. RESULTS: A total of 1144 person-visits derived from 523 participants with available concentrations of TFV-DP in DBS were included in this analysis. In univariate analysis, no significant association between non-AIDS comorbidities (categorized as having 0, 1, 2, or 3 comorbidities) and the concentrations of TFV-DP in DBS was observed (P = 0.40). Participants who had DM had 25% lower (95% confidence interval: -36% to -12%; P < 0.001) TFV-DP in DBS than participants without DM after adjusting for age, gender, race, body mass index, estimated glomerular filtration rate, CD4 T-cell count, hematocrit, ART class, patient-level medication regimen complexity index, and 3-month self-reported adherence. CONCLUSIONS: Diabetic PLWH have lower concentrations of TFV-DP in DBS compared with those without DM. Further research is required to identify the clinical implications and biological mechanisms underlying these findings.

Intracellular Tenofovir-Diphosphate and Emtricitabine-Triphosphate in Dried Blood Spots Following Tenofovir Alafenamide: The TAF-DBS Study.

BACKGROUND: Tenofovir alafenamide (TAF), in combination with FTC, was recently approved for PrEP in the United States. The objective of this study was to assess the relationship between tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP) in dried blood spots (DBS) with adherence to TAF/FTC. METHODS: TAF-DBS was a randomized, crossover clinical study of TFV-DP in DBS, following directly observed dosing of 33%, 67%, or 100% of daily TAF (25 mg)/FTC (200 mg). Healthy volunteers were randomized to 2 different, 12-week dosing regimens, separated by a 12-week washout. DBS were collected weekly. TFV-DP and FTC-TP were extracted from two 7-mm punches and assayed with LC-MS/MS. RESULTS: Thirty-seven participants (17 female, 7 African American, and 6 Hispanic) were included. TFV-DP exhibited a mean half-life of 20.8 days (95% confidence interval: 19.3 to 21.3). The slope for TFV-DP versus dosing arm was 1.14 (90% confidence interval: 1.07 to 1.21). The mean (SD) TFV-DP after 12 weeks was 657 (186), 1451 (501), and 2381 (601) fmol/2 7-mm punches for the 33%, 67%, and 100% arms. The following adherence interpretations are proposed: <450 fmol/punches, <2 doses/wk; 450-949 fmol/punches, 2-3 doses/wk; 950-1799 fmol/punches, 4-6 doses/wk; and ≥1800 fmol/punches, 7 doses/wk. FTC-TP was quantifiable for 1 week after drug cessation in 50%, 92%, and 100% of participants in the 33%, 67%, and 100% arms, respectively. CONCLUSION: TFV-DP in DBS after TAF/FTC exhibited a long half-life and was linearly associated with dosing, similar to its predecessor tenofovir disoproxil fumarate. FTC-TP was quantifiable for up to 1 week after drug cessation. Together, these moieties provide complementary measures of cumulative adherence and recent dosing for TAF/FTC.

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.

Retention, engagement, and adherence to pre-exposure prophylaxis for men who have sex with men and transgender women in PrEP Brasil: 48 week results of a demonstration study.

BACKGROUND: PrEP Brasil was a demonstration study to assess feasibility of daily oral tenofovir diphosphate disoproxil fumarate plus emtricitabine provided at no cost to men who have sex with men (MSM) and transgender women at high risk for HIV within the Brazilian public health system. We report week 48 pre-exposure prophylaxis (PrEP) retention, engagement, and adherence, trends in sexual behaviour, and incidence of HIV and sexually transmitted infections in this study cohort. METHODS: PrEP Brasil was a 48 week, open-label, demonstration study that assessed PrEP delivery at three referral centres for HIV prevention and care in Rio de Janeiro, Brazil (Fundação Oswaldo Cruz), and São Paulo, Brazil (Universidade de São Paulo and Centro de Referência e Treinamento em DST e AIDS). Eligible participants were MSM and transgender women who were HIV negative, aged at least 18 years, resident in Rio de Janeiro or São Paulo, and reported one or more sexual risk criteria in the previous 12 months (eg, condomless anal sex with two or more partners, two or more episodes of anal sex with an HIV-infected partner, or history of sexually transmitted infection [STI] diagnosis). Participants were seen at weeks 4, 12, 24, 36, and 48 for PrEP provision, clinical and laboratory evaluation, and HIV testing. Computer-assisted self-interviews were also done at study visits 12, 24, 36, and 48, and assessed sexual behaviour and drug use. PrEP retention was defined by attendance at the week 48 visit, PrEP engagement was an ordinal five-level variable combining presence at the study visit and drug concentrations, and PrEP adherence was evaluated by measuring tenofovir diphosphate concentrations in dried blood spots. Logistic regression models were used to quantify the association of variables with high adherence (≥4 doses per week). The study is registered with ClinicalTrials.gov, number NCT01989611. FINDINGS: Between April 1, 2014, and July 8, 2016, 450 participants initiated PrEP, 375 (83%) of whom were retained until week 48. At week 48, 277 (74%) of 375 participants had protective drug concentrations consistent with at least four doses per week: 183 (82%) of 222 participants from São Paulo compared with 94 (63%) of 150 participants from Rio de Janeiro (adjusted odds ratio 1·88, 95% CI 1·06-3·34); 119 (80%) of 148 participants who reported sex with HIV-infected partners compared with 158 (70%) of 227 participants who did not (1·78, 1·03-3·08); 67 (87%) of 77 participants who used stimulants compared with 210 (71%) of 298 participants who did not (2·23, 1·02-4·92); and 232 (80%) of 289 participants who had protective concentrations of tenofovir disphosphate at week 4 compared with 42 (54%) of 78 participants who did not (3·28, 1·85-5·80). Overall, receptive anal sex with the last three partners increased from 45% at enrolment to 49% at week 48 (p=0·17), and the mean number of sexual partners in the previous 3 months decreased from 11·4 (SD 28·94) at enrolment to 8·3 (19·55) at week 48 (p<0·0013). Two individuals seroconverted during follow-up (HIV incidence 0·51 per 100 person-years, 95% CI 0·13-2·06); both of these patients had undetectable tenofovir concentrations at seroconversion. INTERPRETATION: Our results support the effectiveness and feasibility of PrEP in a real-world setting. Offering PrEP at public health-care clinics in a middle-income setting can retain high numbers of participants and achieve high levels of adherence without risk compensation in the investigated populations. FUNDING: Brazilian Ministry of Health, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Secretaria de Vigilancia em Saúde, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, and Fundação de Amparo à Pesquisa do Estado de São Paulo.

Brief Report: Adherence Biomarker Measurements in Older and Younger HIV-Infected Adults Receiving Tenofovir-Based Therapy.

BACKGROUND: Concentrations of tenofovir (TFV) in hair and tenofovir diphosphate (TFV-DP) in dried blood spots (DBSs) as measures of cumulative exposure have been primarily studied in younger, HIV-uninfected individuals taking preexposure HIV prophylaxis. Data on these measures among older HIV-infected individuals are limited. METHODS: We evaluated longitudinal TFV and TFV-DP concentrations in hair and DBS, respectively, from HIV-infected adults. Multivariable model variables included age group (18-35 and 60 years and older), creatinine clearance (CrCl), hematocrit (TFV-DP), and gray hair color (TFV). RESULTS: Baseline hair TFV and DBS TFV-DP were moderately correlated [r = 0.5 (0.2 to 0.7); P = 0.001] across both age groups [younger (N = 23) and older (N = 22)]. In adjusted models, CrCl was associated with increases of 15.9% (7.4% to 25.0%); P = 0.0006, and 5.7% (-0.2% to 11.9%); P = 0.057 for TFV in hair and TFV-DP in DBS, respectively, for every 20-mL/min CrCl decrease. Although older age (versus younger age) was univariately associated with increased TFV hair levels, older age was not significantly associated with higher concentrations in hair [-1.4% (-26.7% to 32.7%); P = 0.93] or DBS [4.0% (-14.1% to 25.9%); P = 0.68] after adjustment. Similarly, gray color was not significantly associated with higher TFV levels in hair [27.6% (-11.1% to 83.0%; P = 0.18)] in adjusted models. In both adjusted and unadjusted models of TFV-DP levels in DBS, a 1% hematocrit increase was associated with a 3.3% (0.2% to 6.5%) TFV-DP increase (P = 0.04). CONCLUSIONS: Cumulative drug exposure measures (hair and DBS) were comparable in younger and older HIV-infected individuals on TFV-based therapy after adjustment for renal function.

High pre-exposure prophylaxis uptake and early adherence among men who have sex with men and transgender women at risk for HIV Infection: the PrEP Brasil demonstration project.

INTRODUCTION: The efficacy of pre-exposure prophylaxis (PrEP) in preventing sexual acquisition of human immunodeficiency virus (HIV) is well established. Little is known about the feasibility of PrEP implementation in middle-income settings with concentrated epidemics among men who have sex with men (MSM) and transgender women (TGW). METHODS: PrEP Brasil is a prospective, multicentre, open-label demonstration project assessing PrEP delivery in the context of the Brazilian Public Health System. HIV-uninfected MSM and TGW in 3 referral centres in Rio de Janeiro and São Paulo were evaluated for eligibility and offered 48 weeks of daily emtricitabine/tenofovir for PrEP. Concentrations of tenofovir diphosphate in dried blood spot samples (DBS) at week 4 after enrolment (early adherence) were measured. Predictors of drug levels were assessed using ordinal logistic regression models considering the DBS drug level as a 3 level variable (<350 fmol/punch, ≥350-699 fmol/punch and ≥700 fmol/punch). RESULTS: 1,270 individuals were assessed for participation; n = 738 were potentially eligible and n = 450 were offered PrEP (PrEP uptake was 60.9%). Eligible but not enrolled individuals were younger, had lower HIV risk perception and had lower PrEP awareness. At week 4, 424 participants (of the 450 enrolled) had DBS TFV-DP concentrations, 94.1% in the protective range (≥350 fmol/punch, consistent with ≥2 pills per week), and 78% were in the highly protective range (≥700 fmol/punch, ≥4 pills per week). Participants with ≥12 years of schooling had 1.9 times the odds (95%CI 1.10-3.29) of a higher versus lower drug level than participants with <12 years of schooling. Condomless receptive anal intercourse in the prior 3 months was also associated with higher drug levels (adjusted OR = 1.78; 95% CI 1.08-2.94). CONCLUSION: The high uptake and early adherence indicate that PrEP for high-risk MSM and TGW can be successfully delivered in the context of the Brazilian Public Health System. Interventions to address disparities on PrEP awareness and HIV risk perception among the younger and less educated are urgently needed in order to maximize the impact of this prevention strategy on the reduction of HIV infection among MSM and TGW in Brazil.

Pharmacologic Considerations for Preexposure Prophylaxis in Transgender Women.

Studies of tenofovir disoproxil fumarate (TDF)-emtricitabine (FTC)-based preexposure prophylaxis (PrEP) have not focused on transgendered women who are at disproportionate risk of HIV acquisition. Concerns exist for drug interactions between cross-sex therapy (estradiol, progestins, and spironolactone) with tenofovir disoproxil fumarate-emtricitabine. This review assessed the experimental and theoretical risk for such drug interactions. It was found that none of these medications are implicated as major perpetrators of drug interactions, and the classes use different metabolic pathways for clearance, suggesting a low likelihood for interactions in either direction. Subanalyses of transgender women in Preexposure Prophylaxis Initiative suggested PrEP efficacy if adherence was high. Nevertheless, several research gaps were identified, particularly the need for controlled interaction studies in transgendered women, including effects on renal clearance, intracellular tenofovir diphosphate and emtricitabine triphosphate in target cells, as well as hormone effects on HIV susceptibility and immunity. PrEP should continue to be offered to transgender women while additional research is planned or pending.

Pharmacogenetics of unboosted atazanavir in HIV-infected individuals in resource-limited settings: a sub-study of the AIDS Clinical Trials Group (ACTG) PEARLS study (NWCS 342).

OBJECTIVES: The multinational PEARLS (ACTG A5175) study, conducted mainly in resource-limited settings, identified an increased treatment failure rate among HIV-infected individuals randomized to once-daily unboosted atazanavir, didanosine-EC, and emtricitabine compared with efavirenz-based regimens. We evaluated associations between selected human genetic polymorphisms and atazanavir pharmacokinetics in PEARLS. METHODS: Polymorphisms in CYP3A5, ABCB1, SLCO1B1 and NR1I2 were genotyped in PEARLS participants randomized to atazanavir plus didanosine-EC plus emtricitabine in Peru, South Africa and the USA, who also consented to genetic analysis. Non-linear mixed-effects population pharmacokinetic modelling was used to predict atazanavir oral clearance (CL/F) and concentration at 24 h (C24). Atazanavir mono-oxidation metabolites M1 and M2 were quantified from the same single-point plasma sample used to quantify the parent drug. Data were log10 transformed for statistical analysis using unpaired t-tests and one-way ANOVA and are presented as geometric mean (95% CI). RESULTS: Eighty-four HIV-infected participants were genotyped, including 44 Black Africans or African Americans and 28 women. Median age was 34 years. We identified 56 CYP3A5 expressers and 28 non-expressers. Atazanavir CL/F and C24 did not differ between CYP3A5 expressers and non-expressers: 13.2 (12.1-14.4) versus 12.7 L/h (11.7-13.9), P = 0.61, and 75.3 (46.1-123.0) versus 130.9 ng/mL (86.9-197.2), P = 0.14, respectively. M1/atazanavir and M2/atazanavir ratios were higher in expressers than in non-expressers: 0.0083 (0.0074-0.0094) versus 0.0063 (0.0053-0.0075), P = 0.008, and 0.0065 (0.0057-0.0073) versus 0.0050 (0.0042-0.0061), P = 0.02, respectively. CONCLUSIONS: Expression of CYP3A5 appears to be associated with increased M1 and M2 atazanavir metabolite formation, without significantly affecting parent compound pharmacokinetics.

Study product adherence measurement in the iPrEx placebo-controlled trial: concordance with drug detection.

OBJECTIVE: To evaluate the concordance between adherence estimated by self-report (in-person interview or computer-assisted self-interview), in-clinic pill counts, and pharmacy dispensation records and drug detection among participants in a placebo-controlled pre-exposure prophylaxis HIV prevention trial (iPrEx). DESIGN: Cross-sectional evaluation of 510 participants who had drug concentration data and matched adherence assessments from their week-24 study visit. METHODS: Self-reported adherence collected through (1) interview and (2) computer-assisted self-interview surveys, (3) adherence estimated by pill count, and (4) medication possession ratio was contrasted to having a detectable level of drug concentrations [either tenofovir diphosphate (TFV-DP) or emtricitabine triphosphate (FTC-TP)], as well as to having evidence of consistent dosing (tenofovir diphosphate ≥ 16 fmol/106 cells), focusing on positive predictive values, overall and by research site. RESULTS: Overall, self-report and pharmacy records suggested high rates of product use (over 90% adherence); however, large discrepancies between these measures and drug detection were noted, which varied considerably between sites (positive predictive values from 34% to 62%). Measures of adherence performed generally well in the US sites but had poor accuracy in other research locations. Medication possession ratio outperformed other measures but still had relatively low discrimination. CONCLUSIONS: The sizable discrepancy between adherence measures and drug detection in certain regions highlights the potential contribution of factors that may have incentivized efforts to seem adherent. Understanding the processes driving adherence reporting in some settings, but not others, is essential for finding effective ways to increase accuracy in measurement of product use and may generalize to promotion efforts for open-label pre-exposure prophylaxis.