Hepatitis B virus (HBV) viremia despite tenofovir disoproxil fumarate-containing antiretroviral therapy in persons with HBV/HIV coinfection

BACKGROUND

The goal of treatment of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) coinfection is suppression of both viruses; yet incomplete HBV suppression on tenofovir (TFV) disoproxil fumarate (TDF)-based antiretroviral therapy (ART) is common. This study investigated TFV resistance-associated mutations (RAMs) in individuals with HBV/HIV coinfection with viremia on TDF/lamivudine (3TC)-containing ART.

METHODS

Samples from individuals with HBV DNA levels ≥20 IU/mL in a cross-sectional study of 138 persons with HBV/HIV coinfection in Ghana were analyzed in the present study. HBV was sequenced for RAM analysis. TFV-diphosphate (TFV-DP) concentration in peripheral blood mononuclear cells (PBMCs) was used to assess ART adherence level.

RESULTS

Nine of 138 participants (6.5 %) had detectable HBV DNA levels ≥20 IU/mL while on ART. Seven of the nine participants had TFV-DP concentrations commensurate with 7 doses per week, and six had suppressed HIV RNA. Phylogenetic analysis revealed that eight sequences were HBV genotype E, with one genotype E/A recombinant. Ten previously-reported TFV RAMs were present in the study samples; eight were wild-type for HBV genotype E. The non-genotype-E-wild-type point mutations M267L and K333Q were found in two and one patients, respectively. No 3TC RAMs were found.

CONCLUSION

HBV viremia despite high adherence to TDF/3TC-based ART may be associated with the presence of TFV RAMs. These findings highlight the need for enhanced resistance monitoring and further research to examine the clinical significance of reported TFV RAMs. Individuals with HBV/HIV coinfection and TFV resistance on TDF-based ART may need alternative treatment strategies.

Cumulative Tenofovir Exposure Among Patients With HIV/Hepatitis B Coinfection With Differential Viral Suppression

This case-control study explored cumulative tenofovir exposure among patients with human immunodeficiency virus/hepatis B virus (HIV/HBV) coinfection with HIV viral suppression. Among patients taking tenofovir disoproxil fumarate, median TFV-DP levels in dried blood spots were ∼3-fold lower among patients with incomplete HBV viral suppression (n = 4) compared to those with complete suppression (n = 5) (516 vs 1456 fmol/punch).

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

A Phase 1 Clinical Trial to Assess the Safety and Pharmacokinetics of a Tenofovir Alafenamide/Elvitegravir Insert Administered Rectally for HIV Prevention

BACKGROUND

On-demand topical products could be an important tool for human immunodeficiency virus (HIV) prevention. We evaluated the safety, pharmacokinetics, and ex vivo pharmacodynamics of a tenofovir alafenamide/elvitegravir (TAF/EVG, 20 mg/16 mg) insert administered rectally.

METHODS

MTN-039 was a phase 1, open-label, single-arm, 2-dose study. Blood, rectal fluid, and rectal tissue were collected over 72 hours following rectal administration of 1 and 2 TAF/EVG inserts for each participant.

RESULTS

TAF/EVG inserts were safe and well tolerated. EVG and tenofovir (TFV) were detected in blood plasma at low concentrations: median peak concentrations after 2 inserts were EVG 2.4 ng/mL and TFV 4.4 ng/mL. Rectal tissue EVG peaked at 2 hours (median, 2 inserts = 9 ng/mg) but declined to below limit of quantification in the majority of samples at 24 hours, whereas tenofovir diphosphate (TFV-DP) remained high >2000 fmol/million cells for 72 hours with 2 inserts. Compared to baseline, median cumulative log10 HIV p24 antigen of ex vivo rectal tissue HIV infection was reduced at each time point for both 1 and 2 inserts (P < .065 and P < .039, respectively).

DISCUSSION

Rectal administration of TAF/EVG inserts achieved high rectal tissue concentrations of EVG and TFV-DP with low systemic drug exposure and demonstrable ex vivo inhibition of HIV infection for 72 hours. Clinical Trials Registration . NCT04047420.

Drug Concentrations in Hair and Dried Blood Spots as Preexposure Prophylaxis Adherence Metrics During Pregnancy and Postpartum

We evaluated hair tenofovir (TFV) concentrations as an adherence metric for HIV preexposure prophylaxis during pregnancy and postpartum and compared hair levels with TFV-diphosphate levels in dried blood spots (DBSs). Overall 152 hair samples from 102 women and 36 hair-DBS paired samples from 29 women were collected from a subset of women in a cluster-randomized trial. Having a partner with HIV was associated with higher hair TFV levels (P < .001). Hair TFV concentrations were strongly correlated with DBS TFV-diphosphate levels (r = 0.76, P < .001), indicating hair as a promising cumulative adherence metric for perinatal preexposure prophylaxis assessment.

Pharmacogenetic determinants of tenofovir diphosphate and lamivudine triphosphate concentrations in people with HIV/HBV coinfection

The nucleos(t)ide analogs require phosphorylation to the pharmacologically active anabolites in cells. We investigated the hypothesis that single-nucleotide polymorphisms (SNPs) in genes that encode transporters and phosphodiesterase (PDE) enzymes involved in tenofovir (TFV), disoproxil fumarate (TDF), and lamivudine (3TC) disposition will be associated with concentrations of their phosphate anabolites and virologic response. Individuals with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) coinfection receiving TDF/3TC-containing antiretroviral therapy were enrolled. Steady-state TFV diphosphate (TFV-DP) and 3TC triphosphate (3TC-TP) concentrations in peripheral blood mononuclear cells (PBMCs) and dried blood spot samples were quantified. The relationship between genetic variants and TFV-DP and 3TC-TP concentrations as well as with virologic response were examined using multivariable linear regression. Of the 136 participants (median age 43 years; 63% females), 6.6% had HBV non-suppression, and 7.4% had HIV non-suppression. The multidrug resistance protein 2 (encoded by ABCC2 rs2273697) SNP was associated with 3TC-TP concentrations in PBMCs. The human organic anion transporter-1 (encoded by SLC28A2) rs11854484 SNP was associated with HIV non-suppression, and when evaluated together with SNPs with marginal associations (ABCC2 rs717620 and PDE1C rs30561), participants with two or three variants compared to those with none of these variants had an adjusted odds ratio of 48.3 (confidence interval, 4.3-547.8) for HIV non-suppression. None of the SNPs were associated with HBV non-suppression. Our study identified ABCC2 SNP to be associated with 3TC-TP concentrations in PBMCs. Also, a combination of genetic variants of drug transporters and PDE was associated with HIV non-suppression.

Antiretroviral therapy adherence among peripartum women with HIV in Kenya: an explanatory mixed methods study using dry blood spot measures and narrative interviews

ABSTRACTAdherence to antiretroviral therapy (ART) remains sub-optimal among pregnant and postpartum women with HIV (PPWH) in high HIV prevalence low resource settings with few effective behavioral interventions. A large body of qualitative literature has established general barriers and facilitators to ART adherence in PPWH at various levels (individual, interpersonal, structural). However, research exploring the underlying behavioral mechanisms of ART adherence in PPWH with objectively verified adherence biomarkers is extremely limited. We conducted 24 in-depth interviews with postpartum women in western Kenya who had linked ART drug concentrations obtained from three dried blood spot samples across the peripartum period. Among PPWH with a low drug concentration (n = 13) compared to those with continuously high drug concentrations (n = 11), distinct themes emerged related to HIV status disclosure, social support, interactions with the health system, and health beliefs. By combining ART biomarkers with patient reported challenges, there is the potential for real-time interventions to support sustained ART adherence among PPWH and improve maternal and infant health outcomes.

A Pilot Randomized Controlled Trial of an mHealth Intervention to Improve PrEP Adherence Among Young Sexual Minority Men

This randomized controlled study assessed the feasibility, acceptability, and preliminary impact of the PrEP iT! mHealth intervention designed to improve PrEP adherence among young men who have sex with men (YMSM). A national sample of 80 YMSM in the U.S. (Mage = 25 years; 54% racial/ethnic minority), recruited through social media ads, were randomized to either the PrEP iT! or usual PrEP care conditions. Participants completed online surveys and submitted self-collected dried blood sample (DBS) data as measures of PrEP adherence. Differences in PrEP adherence across treatment arms and between participants with high versus low engagement in PrEP iT! were assessed. Retention was high at the three (94%) and six (93%) month assessment, and participants in PrEP iT! reported satisfactory acceptability of the intervention. There were no significant differences in self-reported or DBS-derived PrEP adherence between randomized groups. However, YMSM in the PrEP iT! group with high PrEP adherence (the equivalent of four or more doses/week through self-report and DBS-derived measures) demonstrated significantly higher engagement in the intervention than those with low PrEP adherence (the equivalent of 3 or fewer doses/week). Overall, the PrEP iT! intervention demonstrated strong feasibility and acceptability. The finding that high PrEP iT! intervention engagement was associated with protective levels of PrEP adherence suggests it is a viable adherence support tool that should be further evaluated in definitive trial among YMSM who need basic support, or as part of a more comprehensive adherence support package for those who need greater assistance.Trial registration Clinical Trials # NCT04509076 (registered August 10, 2020).

Concordance between daily diary reported pre-exposure prophylaxis intake and intraerythrocytic tenofovir diphosphate in the Amsterdam Pre-exposure Prophylaxis demonstration project

OBJECTIVE

We assessed the association and concordance between self-reported oral pre-exposure prophylaxis (PrEP) intake in a diary app and intraerythrocytic drug metabolite concentrations.

DESIGN

AMPrEP was a prospective demonstration study providing daily and event-driven PrEP to MSM in Amsterdam, the Netherlands (2015-2020).

METHODS

Participants could record their PrEP intake in a diary app. Dried blood spots (DBS) were taken at 6, 12, 24, and 48 months and analysed for tenofovir diphosphate (TFV-DP) and emtricitabine triphosphate (FTC-TP) concentrations. We included TFV-DP measurements preceded by diary completion on at least 90% of days in the 6 weeks prior. We examined the association between self-reported PrEP intake (i.e. number of pills) and TFV-DP concentrations using tobit regression with a random intercept per participant. We also calculated concordance between categorized PrEP intake (i.e. <2, 2-3, 4-6 or 7 pills per week) and categorized TFV-DP concentrations (i.e. <350, 350-699,700-1249 or ≥1250 fmol/punch) using weighted Cohen's kappa. Last, we calculated concordance between self-reported recent PrEP intake (yes/no, in past 2 days) and quantifiability of FTC-TP (yes/no) using Cohen's kappa.

RESULTS

Seven hundred and fifty-nine DBS measurements from 282 MSM were included. Self-reported PrEP intake was strongly and positively associated with TFV-DP concentration ( β  = 0.77, 95% CI = 0.70-0.84, P  < 0.0001). Concordance between categorized PrEP intake and TFV-DP concentration was moderate ( κ  = 0.44, 95% CI = 0.39-0.50). Concordance between self-reported recent PrEP intake and FTC-TP quantifiability was perfect ( κ  = 0.83, 95% CI 0.76-0.90).

CONCLUSION

Self-reported PrEP intake in a diary app is strongly correlated with actual use, and therefore reliable for comparing PrEP adherence between groups. Still, suboptimal criterion validity according to clinically relevant categories warrants caution when assessing 6-week reported adherence for individuals.

Establishing adherence-concentration-efficacy thresholds of TDF-FTC pre-exposure prophylaxis for HIV prevention in African women: a protocol for the Women TDF-FTC Benchmark Study

Background

Oral pre-exposure prophylaxis (PrEP) using co-formulated emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) is a potent HIV prevention method for men and women, with its efficacy highly dependent on adherence. A pivotal HIV efficacy study combined with a directly observed pharmacological study defined the thresholds for HIV protection in men who have sex with men (MSM), which are the keys to PrEP promotion and development of new PrEP agents. For African women at risk for HIV and belonging to a priority group considered due to disproportionately high incident HIV infections, the variable adherence in PrEP clinical trials and the limited pharmacologic data have resulted in a lack of clarity about the PrEP adherence required for HIV protection. We propose a study to quantify the adherence-concentration-efficacy thresholds of TDF/FTC PrEP among African cisgender women to inform decisions about optimal PrEP dosing and adherence for HIV protection.

Methods

We randomized 45 low-risk HIV-uninfected African women, aged 18-30 years old, to directly observe the TDF/FTC PrEP of two, four, or seven doses per week for 8 weeks. A complementary age-matched pregnant women cohort at high risk of HIV, who will receive seven doses per week, was recruited (N = 15) with the primary aim of establishing benchmark concentrations in dried blood spots and peripheral blood mononuclear cells. Plasma, whole blood (WB), urine, hair, vaginal fluid, and vaginal tissue (non-pregnant women only) were archived for future testing. Drug concentrations were measured using methods validated for each biological matrix. Pharmacokinetic models were fitted to drug concentrations to quantify concentration-adherence thresholds. To define the drug concentrations associated with HIV protection, we applied the newly defined thresholds from the primary pharmacologic trial to the subset of women randomized to TDF/FTC or TDF in the Partners PrEP Study with the drug concentration assessed in plasma and WB samples. Multiple imputation was used to construct a data set with drug concentrations at each visit when an HIV test was performed for the entire cohort, replicating the work for MSM.

Discussion

The proposed study generated the first African women-specific TDF-PrEP adherence-concentration-efficacy thresholds essential for guiding the accurate interpretation of TDF/FTC PrEP programs and clinical trials of novel HIV prevention products using TDF/FTC as an active control.

Clinical Trial Registration

ClinicalTrials.gov, identifier (NCT05057858).

Sexual behaviour and incidence of sexually transmitted infections among men who have sex with men (MSM) using daily and event-driven pre-exposure prophylaxis (PrEP): Four-year follow-up of the Amsterdam PrEP (AMPrEP) demonstration project cohort

BACKGROUND

An increasing number of countries are currently implementing or scaling-up HIV pre-exposure prophylaxis (PrEP) care. With the introduction of PrEP, there was apprehension that condom use would decline and sexually transmitted infections (STIs) would increase. To inform sexual health counselling and STI screening programmes, we aimed to study sexual behaviour and STI incidence among men who have sex with men (MSM) and transgender women who use long-term daily or event-driven PrEP.

METHODS AND FINDINGS

The Amsterdam PrEP demonstration project (AMPrEP) was a prospective, closed cohort study, providing oral daily PrEP and event-driven PrEP to MSM and transgender women from 2015 to 2020. Participants could choose their PrEP regimen and could switch at each three-monthly visit. STI testing occurred at and, upon request, in-between 3-monthly study visits. We assessed changes in numbers of sex partners and condomless anal sex (CAS) acts with casual partners over time using negative binomial regression, adjusted for age. We assessed HIV incidence and changes in incidence rates (IRs) of any STI (i.e., chlamydia, gonorrhoea, or infectious syphilis) and individual STIs over time using Poisson regression, adjusted for age and testing frequency. A total of 367 participants (365 MSM) commenced PrEP and were followed for a median 3.9 years (interquartile range [IQR] = 3.4-4.0). Median age was 40 years (IQR = 32-48), 315 participants (85.8%) self-declared ethnicity as white and 280 (76.3%) had a university or university of applied sciences degree. Overall median number of sex partners (past 3 months) was 13 (IQR = 6-26) and decreased per additional year on PrEP (adjusted rate ratio [aRR] = 0.86/year, 95% confidence interval [CI] = 0.83-0.88). Overall median number of CAS acts with casual partners (past 3 months) was 10 (IQR = 3-20.5) and also decreased (aRR = 0.92/year, 95% CI = 0.88-0.97). We diagnosed any STI in 1,092 consultations during 1,258 person years, resulting in an IR of 87/100 person years (95% CI = 82-92). IRs of any STI did not increase over time for daily PrEP or event-driven PrEP users. Two daily PrEP users, and no event-driven PrEP users, were diagnosed with HIV during their first year on PrEP. Study limitations include censoring follow-up due to COVID-19 measures and an underrepresentation of younger, non-white, practically educated, and transgender individuals.

CONCLUSIONS

In this prospective cohort with a comparatively long follow-up period of 4 years, we observed very low HIV incidence and decreases in the numbers of casual sex partners and CAS acts over time. Although the STI incidence was high, it did not increase over time.

TRIAL REGISTRATION

The study was registered at the Netherlands Trial Register (NL5413) https://www.onderzoekmetmensen.nl/en/trial/22706.

The Effect of Disclosure of PrEP Use on Adherence Among African Young Women in an Open-Label PrEP Study: Findings from HPTN 082

To develop effective PrEP adherence interventions, it is important to understand the interplay between disclosure of pre-exposure prophalxis (PrEP) use, social support, and PrEP adherence. We leveraged the HPTN 082 study conducted among 451 adolescent girls and young women (AGYW) (ages 16 to 25 years, 2016 to 2019) in South Africa and Zimbabwe. Among the 349 who had month three disclosure and PrEP adherence data, 60% (n = 206) felt supported by adults, and 89% (n = 309) disclosed PrEP use to at least one person. PrEP disclosure was not associated with increased adherence, measured by intracellular tenofovir-diphosphate concentrations in dried blood spots. Women who reported having supportive adults, and disclosed to their parents, had higher adherence at 6 months with an increase of 177 fmol/punch (95% CI 12 to 343, t = 2.11, p = 0.04). PrEP interventions that help AGYW identify supportive relationships and effectively communicate the benefits of PrEP may improve PrEP adherence.Clinicaltrials.gov ID number: NCT02732730.

Tenofovir-Diphosphate and Emtricitabine-Triphosphate Adherence Benchmarks in Dried Blood Spots for Persons with HIV Receiving Tenofovir Alafenamide and Emtricitabine-based Antiretroviral Therapy (QUANTI-TAF)

BACKGROUND

QUANTI-TAF aimed to establish tenofovir-diphosphate/emtricitabine-triphosphate (TFV-DP/FTC-TP) adherence benchmarks in dried blood spots (DBS) for persons with HIV (PWH) receiving tenofovir alafenamide/emtricitabine (TAF/FTC)-based antiretroviral therapy (ART).

METHODS

During a 16-week pharmacokinetic study, PWH received TAF/FTC-based ART co-encapsulated with an ingestible sensor to directly measure cumulative (enrollment to final visit) and 10-day adherence. At monthly visits, intraerythrocytic concentrations of TAF/FTC anabolites (TFV-DP/FTC-TP) in DBS were quantified by LC-MS/MS and summarized at steady-state (week 12 or 16) as median (IQR). Linear mixed-effects models evaluated factors associated with TFV-DP/FTC-TP.

RESULTS

84 participants (86% male, 11% female, and 4% transgender), predominantly receiving bictegravir/TAF/FTC (73%) enrolled. 92% completed week 12 or 16 (94% receiving unboosted ART). TFV-DP for <85% (7/72), ≥85%-<95% (9/72), and ≥95% (56/72) cumulative adherence was 2696 (2039-4108), 3117 (2332-3339), and 3344 (2605-4293) fmol/punches. All participants with ≥85% cumulative adherence had TFV-DP ≥1800 fmol/punches. Adjusting for cumulative adherence, TFV-DP was higher with boosted ART, lower BMI, and in non-Blacks. FTC-TP for <85% (14/77), ≥85%-<95% (6/77), and ≥95% (57/77) 10-day adherence was 3.52 (2.64-4.48), 4.58 (4.39-5.06), and 4.96 (4.21-6.26) pmol/punches. All participants with ≥85% 10-day adherence had FTC-TP ≥2.5 pmol/punches. Low-level viremia (HIV-1 RNA ≥20-<200 copies/mL) occurred at 60/335 (18%) visits in 33/84 (39%) participants (range: 20-149 copies/mL), with similar TFV-DP (3177 [2494-4149] fmol/punches) compared with HIV-1 RNA <20 copies/mL visits (3279 [2580-4407] fmol/punches).

CONCLUSIONS

We propose PK-based TFV-DP (≥1800 fmol/punches)/FTC-TP (≥2.5 pmol/punches) benchmarks in DBS for PWH receiving unboosted TAF/FTC-based ART with ≥85% adherence. In the setting of high adherence, low-level viremia was common.

Association of tenofovir diphosphate and lamivudine triphosphate concentrations with HIV and hepatitis B virus viral suppression

OBJECTIVE

Concentrations of tenofovir diphosphate (TFV-DP) and lamivudine triphosphate (3TC-TP) in cells are correlates of medication adherence and antiviral activity. However, studies have yet to characterize the simultaneous relationship between TFV-DP and 3TC-TP concentrations with HIV and hepatitis B virus (HBV) suppression.

METHODS

Individuals with HIV/HBV coinfection on tenofovir disoproxil fumarate (TDF)-containing antiretroviral therapy (ART) were enrolled. Peripheral blood mononuclear cells (PBMCs) and dried blood spots (DBS) samples were collected and steady-state TFV-DP and 3TC-TP concentrations quantified using validated methods. The relationship between patient factors, TFV-DP, and 3TC-TP concentrations in PBMCs and DBS with HBV and HIV viral suppression were examined.

RESULTS

Of 138 participants on TDF-containing ART for a median duration (range) of 6 (0.75-15) years, the median age was 43 years and 64% were women. Overall, 128 (92.8%) and 129 (93.5%) had suppressed HIV and HBV viral loads, respectively. Of the 128 participants with suppressed HIV, 122 (95.3%) had suppressed HBV. Self-reported ART adherence, recent change to dolutegravir-based ART, TFV-DP, and 3TC-TP concentrations in PBMCs and DBS were associated with HIV RNA suppression, while HBe antigen positivity, HIV suppression, and TFV-DP concentrations in DBS were associated with HBV DNA suppression (including six persons with HBV nonsuppression and HIV suppression).

CONCLUSION

Long-term TDF/3TC-conatining ART was highly efficacious in individuals with HIV/HBV coinfection. Higher TFV-DP concentrations were predictive of suppression for both viruses. Persistent HBV viremia on TDF/3TC-containg ART requires additional research, but may represent poor adherence and the need for adherence interventions or novel antivirals.

Antiviral potency of long-acting islatravir subdermal implant in SHIV-infected macaques

Treatment nonadherence is a pressing issue in people living with HIV (PLWH), as they require lifelong therapy to maintain viral suppression. Poor adherence leads to antiretroviral (ARV) resistance, transmission to others, AIDS progression, and increased morbidity and mortality. Long-acting (LA) ARV therapy is a promising strategy to combat the clinical drawback of user-dependent dosing. Islatravir (ISL) is a promising candidate for HIV treatment given its long half-life and high potency. Here we show constant ISL release from a subdermal LA nanofluidic implant achieves viral load reduction in SHIV-infected macaques. Specifically, a mean delivery dosage of 0.21 ± 0.07 mg/kg/day yielded a mean viral load reduction of -2.30 ± 0.53 log10 copies/mL at week 2, compared to baseline. The antiviral potency of the ISL delivered from the nanofluidic implant was higher than oral ISL dosed either daily or weekly. At week 3, viral resistance to ISL emerged in 2 out of 8 macaques, attributable to M184V mutation, supporting the need of combining ISL with other ARV for HIV treatment. The ISL implant produced moderate reactivity in the surrounding tissue, indicating tolerability. Overall, we present the ISL subdermal implant as a promising approach for LA ARV treatment in PLWH.

Performance of Multiple Adherence Measures for pre-exposure Prophylaxis (PrEP) Among Young Women in Kenya

Understanding PrEP adherence is key in the formulation of HIV prevention strategies; however, measurement of adherence can be challenging. We compared multiple adherence measures in a two-year study of young Kenyan women at high risk of HIV acquisition. Among 289 participants, concordance between electronic adherence monitoring (EAM) and tenofovir diphosphate (TFV-DP) in dried blood spots ranged from 57 to 72% depending on selected thresholds. Using area under the receiver operating curve, discrimination of quantifiable TFV-DP was high at 0.85 with EAM and low at 0.49-0.54 for multiple self-reported measures. Correlation between EAM and self-reported measures was low (r < 0.11) although correlation within self-reported measures was moderate (r > 0.69). These findings indicate that both TFV-DP and EAM are useful PrEP adherence tools. Adherence would benefit from better availability of less expensive versions of both measurement tools. Additionally, further research on TFV-DP thresholds is needed to inform interpretation and use in understanding PrEP adherence in this population.

Viral and host mediators of non-suppressible HIV-1 viremia

Non-suppressible HIV-1 viremia (NSV) is defined as persistent low-level viremia on antiretroviral therapy (ART) without evidence of ART non-adherence or significant drug resistance. Unraveling the mechanisms behind NSV would broaden our understanding of HIV-1 persistence. Here we analyzed plasma virus sequences in eight ART-treated individuals with NSV (88% male) and show that they are composed of large clones without evidence of viral evolution over time in those with longitudinal samples. We defined proviruses that match plasma HIV-1 RNA sequences as 'producer proviruses', and those that did not as 'non-producer proviruses'. Non-suppressible viremia arose from expanded clones of producer proviruses that were significantly larger than the genome-intact proviral reservoir of ART-suppressed individuals. Integration sites of producer proviruses were enriched in proximity to the activating H3K36me3 epigenetic mark. CD4+ T cells from participants with NSV demonstrated upregulation of anti-apoptotic genes and downregulation of pro-apoptotic and type I/II interferon-related pathways. Furthermore, participants with NSV showed significantly lower HIV-specific CD8+ T cell responses compared with untreated viremic controllers with similar viral loads. We identified potential critical host and viral mediators of NSV that may represent targets to disrupt HIV-1 persistence.

Efficacy and safety of long-acting cabotegravir compared with daily oral tenofovir disoproxil fumarate plus emtricitabine to prevent HIV infection in cisgender men and transgender women who have sex with men 1 year after study unblinding: a secondary analysis of the phase 2b and 3 HPTN 083 randomised controlled trial

BACKGROUND

Injectable cabotegravir was superior to daily oral tenofovir disoproxil fumarate plus emtricitabine for HIV prevention in two clinical trials. Both trials had the primary aim of establishing the HIV prevention efficacy of long-acting injectable cabotegravir pre-exposure prophylaxis (PrEP) compared with tenofovir disoproxil fumarate plus emtricitabine daily oral PrEP. Long-acting PrEP was associated with diagnostic delays and integrase strand-transfer inhibitor (INSTI) resistance. This report presents findings from the first unblinded year of the HIV Prevention Trials Network (HPTN) 083 study.

METHODS

The HPTN 083 randomised controlled trial enrolled HIV-uninfected cisgender men and transgender women at elevated HIV risk who have sex with men, from 43 clinical research sites in Africa, Asia, Latin America, and the USA. Inclusion criteria included: a negative HIV serological test at the screening and study entry, undetectable HIV RNA levels within 14 days of study entry, age 18 years or older, overall good health as determined by clinical and laboratory evaluations, and a creatinine clearance of 60 mL/min or higher. Participants were randomly allocated to receive long-acting injectable cabotegravir or daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP. After study unblinding, participants remained on their original regimen awaiting an extension study. HIV infections were characterised retrospectively at a central laboratory. Here we report the secondary analysis of efficacy and safety for the first unblinded year. The primary outcome was incident HIV infection. Efficacy analyses were done on the modified intention-to-treat population using a Cox regression model. Adverse events were compared across treatment groups and time periods (blinded vs unblinded). This trial is registered with ClinicalTrials.gov, NCT02720094.

FINDINGS

Of the 4488 participants who contributed person-time to the blinded analysis, 3290 contributed person-time to the first unblinded year analysis between May 15, 2020, and May 14, 2021. Updated HIV incidence in the blinded phase was 0·41 per 100 person-years for long-acting injectable cabotegravir PrEP and 1·29 per 100 person-years for daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP (hazard ratio [HR] 0·31 [95% CI 0·17-0·58], p=0·0003). HIV incidence in the first unblinded year was 0·82 per 100 person-years for long-acting PrEP and 2·27 per 100 person-years for daily oral PrEP (HR 0·35 [0·18-0·69], p=0·002). Adherence to both study products decreased after study unblinding. Additional infections in the long-acting PrEP group included two with on-time injections; three with one or more delayed injections; two detected with long-acting PrEP reinitiation; and 11 more than 6 months after their last injection. Infection within 6 months of cabotegravir exposure was associated with diagnostic delays and INSTI resistance. Adverse events were generally consistent with previous reports; incident hypertension in the long-acting PrEP group requires further investigation.

INTERPRETATION

Long-acting injectable cabotegravir PrEP retained high efficacy for HIV prevention in men and transgender women who have sex with men during the first year of open-label follow-up, with a near-identical HR for HIV risk reduction between long-acting injectable cabotegravir and daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP during the first year after unblinding compared with the blinded period. Extended follow-up further defined the risk period for diagnostic delays and emergence of INSTI resistance.

FUNDING

Division of AIDS at the National Institute of Allergy and Infectious Diseases, ViiV Healthcare, and Gilead Sciences.

Measuring ART Adherence Among Young Adults with Perinatally Acquired HIV: Comparison Between Self-report, Telephone-Based Pill Count, and Objective Pharmacologic Measures

Tenofovir diphosphate (TVF-DP) can be quantified in red blood cells (RBCs) and dried blood spots (DBS) and can objectively measure ART adherence and predict viral suppression. Data on the association of TFV-DP with viral load are very limited in adolescents and young adults (AYA) living with perinatally-acquired HIV (PHIV), as are data comparing TFV-DP to other measures of ART adherence, such as self-report and unannounced telephone pill count. Viral load and ART adherence (self-report, TFV-DP and unannounced telephone pill count) were assessed and compared among 61 AYAPHIV recruited from an ongoing longitudinal study (CASAH) in New York City.

Adults on pre-exposure prophylaxis (tenofovir-emtricitabine) have faster clearance of anti-HIV monoclonal antibody VRC01

Broadly neutralizing monoclonal antibodies (mAbs) are being developed for HIV-1 prevention. Hence, these mAbs and licensed oral pre-exposure prophylaxis (PrEP) (tenofovir-emtricitabine) can be concomitantly administered in clinical trials. In 48 US participants (men and transgender persons who have sex with men) who received the HIV-1 mAb VRC01 and remained HIV-free in an antibody-mediated-prevention trial (ClinicalTrials.gov #NCT02716675), we conduct a post-hoc analysis and find that VRC01 clearance is 0.08 L/day faster (p = 0.005), and dose-normalized area-under-the-curve of VRC01 serum concentration over-time is 0.29 day/mL lower (p < 0.001) in PrEP users (n = 24) vs. non-PrEP users (n = 24). Consequently, PrEP users are predicted to have 14% lower VRC01 neutralization-mediated prevention efficacy against circulating HIV-1 strains. VRC01 clearance is positively associated (r = 0.33, p = 0.03) with levels of serum intestinal Fatty Acid Binding protein (I-FABP), a marker of epithelial intestinal permeability, which is elevated upon starting PrEP (p = 0.04) and after months of self-reported use (p = 0.001). These findings have implications for the evaluation of future HIV-1 mAbs and postulate a potential mechanism for mAb clearance in the context of PrEP.

Efficacy estimates of oral pre-exposure prophylaxis for HIV prevention in cisgender women with partial adherence

Pre-exposure prophylaxis (PrEP) with tenofovir (TFV) disoproxil fumarate and emtricitabine administered orally daily is effective in preventing human immunodeficiency virus (HIV) acquisition in both men and women with sufficient adherence; however, the adherence-efficacy relationship in cisgender women has not been well established. We calculated the adherence-efficacy curve for cisgender women by using HIV incidence and plasma TFV concentration data from three trials (FEM-PrEP, VOICE and Partners PrEP). We imputed TFV diphosphate (TFV-DP) concentrations, a measure of long-term adherence, from TFV quantification by using data from the HIV Prevention Trials Network 082 study, which measured both TFV-DP and TFV concentrations. Two, four and seven pills per week reduced HIV incidence by 59.3% (95% credible interval (CrI) 29.9-95.8%), 83.8% (95% CI 51.7-99.8%) and 95.9% (95% CI 72.6-100%), respectively. Our adherence-efficacy curve can be validated and updated by HIV prevention studies that directly measure TFV-DP concentrations. The curve suggests that high adherence confers high protection in cisgender women. However, the lower efficacy with partial adherence highlights the need for new PrEP products and interventions to increase adherence.

Acceptability and Feasibility of Providing Adherence Feedback Based on Tenofovir Diphosphate in Dried Blood Spots: Results from a Pilot Study Among Patients and Providers in Cape Town, South Africa

Tenofovir diphosphate (TFV-DP) concentrations in dried blood spots (DBS) predict viral breakthrough, but their use remains understudied in real-world clinic settings. This pilot study examined acceptability, feasibility, and initial adherence outcomes of providing adherence feedback using TFV-DP concentrations on patient- and provider-levels in Cape Town, South Africa. We enrolled 60 persons with HIV (PWH) receiving tenofovir-containing ART attending a primary health clinic. They were randomized 1:1 to an intervention receiving TFV-DP concentration feedback by research staff vs. no feedback at monthly visits for 4 months. Acceptability among medical providers and level of clinical follow-up of TFV-DP results was examined. Patient acceptability was assessed descriptively. Mean electronic adherence (EA), as measured by WisePill device, and TFV-DP in DBS were compared between the two arms. All participants in the intervention group (100%) reported finding TFV-DP feedback helpful and 86% reported changing adherence behaviors. Medical providers indicated high acceptability of incorporating TFV-DP concentration feedback into the clinic, yet among 29 results < 1000 fmol/punch, only 2 were reviewed with no follow-up actions performed. In the intervention arm, mean TFV-DP concentrations were significantly higher (t = 2.5, p < .01) during follow-up and EA in upper quartile (96-100%) was greater compared to controls (x2 = 7.8, p ≤ .05). This study found high acceptability among patients for receiving adherence feedback based on TFV-DP concentrations. TFV-DP and EA data demonstrated greater adherence in the intervention group. Providers indicated high acceptability of incorporating TFV-DP feedback into the clinic, but few providers reviewed results, which could impact clinic-level feasibility.

Tenofovir diphosphate in dried blood spots and HIV-1 resistance in South Africa

BACKGROUND

Suboptimal antiretroviral (ART) adherence can lead to virologic failure with consequent HIV-1 resistance. Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) is a powerful biomarker of cumulative adherence, predictive of future viremia. It has been associated with resistance in Persons With HIV (PWH) in South Africa and the US. We explored the relationship of TFV-DP concentrations with antiretroviral drug resistance at the time of treatment failure in SA.

METHODS

Adult PWH from health clinics in Cape Town, South Africa on efavirenz-based first-line ART containing tenofovir disoproxil fumarate (TDF) with an undetectable (< 50 copies/mL) HIV-1 viral load (VL) were prospectively enrolled in an observational cohort for 12 months. Monthly study visits included blood collection for HIV-1 VL and DBS for TFV-DP. The first confirmed viral breakthrough (VB) > 400 copies/mL triggered HIV-1 genotyping at the subsequent visit. An electronic adherence (EA) device monitored ART adherence in real-time, estimated as a percent for the 30-days prior to VB. Wilcoxon rank sum test was used to compare median [IQR] TFV-DP by genotype outcome.

RESULTS

Of 250 individuals, (n = 195, 78% women), 21 experienced VB, with a median of 5 [4;7] months on study, and a median EA of 33.3 [13.3;53.3]%. Demographic characteristics between those with and without VB were similar. Median VL at VB was 4.0 [3.2;4.5] log copies/mL. TFV-DP concentrations trended down towards the VB visit. Median TFV-DP concentrations were significantly higher in those HIV-1 genotype did not amplify due to being virally suppressed at the subsequent visit (n = 10; 380 [227-661] fmol/punch, p = 0.035; EA 45 [24.9; 59.2]%); than in those who were successfully genotyped with evidence of drug resistance (n = 5, 241 [150-247] fmol/punch, EA 20 [6.7;36.7]%) and in individuals who did not have resistance (n = 3, 39.9 [16.6; 93.9] fmol/punch; EA 33.3 [16-38]%). Three genotype collections were not done. Only non-nucleoside reverse transcriptase inhibitor-associated mutations were identified on resistance testing. (K103N, E138K, Y118H).

CONCLUSION

TFV-DP in DBS showed a step-wise inverse relationship with VB and drug resistance, with evidence of low cumulative ART adherence in PWH who developed antiretroviral resistance. Monitoring TFV-DP concentrations could be a valuable tool for predicting future VB and future resistance.

HIV pre-exposure prophylaxis initiation, persistence, and adherence during pregnancy through the postpartum period

OBJECTIVE

We evaluated pre-exposure prophylaxis (PrEP) initiation, persistence, and adherence measured via tenofovir-diphosphate (TFV-DP) concentrations in dried blood spots (DBS) among women offered PrEP during pregnancy.

METHODS

We prospectively analyzed data from participants in the PrIMA Study (NCT03070600) who were offered PrEP during the second trimester and followed through 9 months postpartum. At follow-up visits (monthly in pregnancy; 6 weeks, 6 months, 9 months postpartum), self-reported PrEP use was assessed, and DBS were collected for quantifying TFV-DP concentrations.

RESULTS

In total, 2949 participants were included in the analysis. At enrollment, median age was 24 years [interquartile range IQR) 21-29], gestational age 24 weeks (IQR 20-28), and 4% had a known partner living with HIV. Overall, 405 (14%) participants initiated PrEP in pregnancy with higher frequency among those with risk factors for HIV acquisition, including >2 lifetime sexual partners, syphilis during pregnancy, forced sex, and intimate partner violence ( P  < 0.05). At 9 months postpartum, 58% of PrEP initiators persisted with PrEP use, of which 54% self-reported not missing any PrEP pills in the last 30 days. Among DBS randomly selected from visits where participants persisted with PrEP ( n  = 427), 50% had quantifiable TFV-DP. Quantifiable TFV-DP was twice as likely in pregnancy than postpartum [adjusted risk ratio (aRR) = 1.90, 95% confidence interval (CI) 1.40-2.57, P  < 0.001]. Having a partner known to be living with HIV was the strongest predictor of PrEP initiation, persistence, and quantifiable TFV-DP ( P  < 0.001).

CONCLUSIONS

PrEP persistence and adherence waned postpartum, though over half of PrEP initiators persisted through 9-months postpartum. Interventions should prioritize increasing knowledge of partner HIV status and sustaining adherence in the postpartum period.