Application of an intracellular assay for determination of tenofovir-diphosphate and emtricitabine-triphosphate from erythrocytes using dried blood spots

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.

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.

The impact of intimate partner violence on PrEP adherence among U.S. Cisgender women at risk for HIV

BACKGROUND

Cisgender women account for 1 in 5 new HIV infections in the United States, yet remain under-engaged in HIV prevention. Women experiencing violence face risk for HIV due to biological and behavioral mechanisms, and barriers to prevention, such as challenges to Pre-Exposure Prophylaxis for HIV Prevention (PrEP) adherence. In this analysis, we aim to characterize intimate partner violence (IPV) among cisgender heterosexual women enrolled in a PrEP demonstration project and assess the associations with PrEP adherence.

METHODS

Adherence Enhancement Guided by Individualized Texting and Drug Levels (AEGiS) was a 48-week single-arm open-label study of PrEP adherence in HIV-negative cisgender women in Southern California (N = 130) offered daily tenofovir disoproxil fumarate/emtricitabine (TDF/FTC). From 6/2016 to 10/2018, women completed a survey reporting HIV risk behavior and experiences of any IPV (past 90-days) and IPV sub-types (past-year, lifetime) and biological testing for HIV/STIs at baseline, and concentrations of tenofovir-diphosphate (TFV-DP) in dried blood spots at weeks 4, 12, 24, 36, and 48. Outcomes were TFV-DP concentrations consistent with ≥ 4 or ≥ 6 doses/week at one or multiple visits. Multivariable logistic regression models were conducted to examine associations.

RESULTS

Past-90-day IPV was reported by 34.4% of participants, and past-year and lifetime subtypes reported by 11.5-41.5%, and 21.5-52.3%, respectively. Women who engaged in sex work and Black women were significantly more likely to report IPV than others. Lifetime physical IPV was negatively associated with adherence at ≥ 4 doses/week at ≥ 3 of 5 visits, while other relationships with any IPV and IPV sub-types were variable.

CONCLUSION

IPV is an indication for PrEP and important indicator of HIV risk; our findings suggest that physical IPV may also negatively impact long-term PrEP adherence.

CLINICAL TRIALS REGISTRATION

NCT02584140 (ClinicalTrials.gov), registered 15/10/2015.

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).

Intimate Partner Violence and Adherence to PrEP and ART Among Ugandan HIV Serodifferent Couples

BACKGROUND

Intimate partner violence (IPV) is associated with increased risk of HIV acquisition and reduced engagement in HIV care. There is limited understanding of the ways in which IPV exposure and other maladaptive relationship dynamics may influence adherence to antiretroviral treatment (ART) and pre-exposure prophylaxis (PrEP) for individuals in committed, HIV serodifferent partnerships.

METHODS

We used binomial generalized linear mixed-effect regression models to evaluate the association between IPV exposure and ART/PrEP adherence among members of serodifferent couples in Uganda. Secondarily, we assessed the association between relationship powerlessness and ART/PrEP adherence.

RESULTS

We enrolled and followed both partners in 149 heterosexual serodifferent couples. The partner living with HIV was female in 64% of couples. IPV exposure was associated with low ART adherence (15% vs. 5% in quarters with no IPV, odds ratio: 4.78, 95% confidence interval: 1.48 to 15.42), but not low PrEP adherence (33% vs. 36%, P = 0.69). Among HIV-negative individuals, those reporting moderate relationship powerlessness were less likely to have poor PrEP adherence compared with those with low relationship powerlessness (20% vs. 30%, odds ratio: 0.57, 95% confidence interval: 0.36 to 0.90). We observed no association between relationship powerlessness and ART adherence.

CONCLUSIONS

We found that IPV exposure was associated with low adherence to ART and that relationship powerlessness was associated with good adherence to PrEP. These findings contribute to the evidence base outlining the influence of IPV and relationship power on ART/PrEP adherence for individuals in HIV serodifferent unions.

HIV-1 Incidence, Adherence, and Drug Resistance in Individuals Taking Daily Emtricitabine/Tenofovir Disoproxil Fumarate for HIV-1 Pre-Exposure Prophylaxis: Pooled Analysis From 72 Global Studies

BACKGROUND

Oral pre-exposure prophylaxis (PrEP) with emtricitabine/tenofovir disoproxil fumarate (F/TDF) has high efficacy against HIV-1 acquisition. Seventy-two prospective studies of daily oral F/TDF PrEP were conducted to evaluate HIV-1 incidence, drug resistance, adherence, and bone and renal safety in diverse settings.

METHODS

HIV-1 incidence was calculated from incident HIV-1 diagnoses after PrEP initiation and within 60 days of discontinuation. Tenofovir concentration in dried blood spots (DBS), drug resistance, and bone/renal safety indicators were evaluated in a subset of studies.

RESULTS

Among 17,274 participants, there were 101 cases with new HIV-1 diagnosis (0.77 per 100 person-years; 95% CI 0.63-0.94). In 78 cases with resistance data, 18 (23%) had M184I or V, one (1.3%) had K65R, and three (3.8%) had both mutations. In 54 cases with tenofovir concentration data from DBS, 45 (83.3%), 2 (3.7%), 6 (11.1%), and 1 (1.9%) had average adherence of <2, 2-3, 4-6, and ≥7 doses/week, respectively, and the corresponding incidence was 3.9 (95% CI 2.9-5.3), 0.24 (0.060-0.95), 0.27 (0.12-0.60), and 0.054 (0.008-0.38) per 100 person-years. Adherence was low in younger participants, Hispanic/Latinx and Black participants, cisgender women, and transgender women. Bone and renal adverse event incidence rates were 0.69 and 11.8 per 100 person-years, respectively, consistent with previous reports.

CONCLUSIONS

Leveraging the largest pooled analysis of global PrEP studies to date, we demonstrate that F/TDF is safe and highly effective, even with less than daily dosing, in diverse clinical settings, geographies, populations, and routes of HIV-1 exposure.

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.

HIV-1 reservoir size after neonatal antiretroviral therapy and the potential to evaluate antiretroviral-therapy-free remission (IMPAACT P1115): a phase 1/2 proof-of-concept study

BACKGROUND

Infants born with HIV-1 require lifelong antiretroviral therapy (ART). We aimed to assess whether very early ART in neonates might restrict HIV-1 reservoirs, an important step towards ART-free remission.

METHODS

IMPAACT P1115 is an ongoing, phase 1/2, proof-of-concept study in which infants were enrolled at 30 research clinics in 11 countries (Brazil, Haiti, Kenya, Malawi, South Africa, Tanzania, Thailand, Uganda, the USA, Zambia, and Zimbabwe) into two cohorts. Infants at least 34 weeks' gestational age at high risk for in-utero HIV-1 with either untreated maternal HIV-1 (cohort 1) or who were receiving pre-emptive triple antiretroviral prophylaxis outside of the study (maternal ART permissible; cohort 2) were included. All infants initiated treatment within 48 h of life. Cohort 1 initiated three-drug nevirapine-based ART, and cohort 2 initiated three-drug nevirapine-based prophylaxis then three-drug nevirapine-based ART following HIV diagnosis by age 10 days. We added twice-daily coformulated oral ritonavir 75 mg/m2 and lopinavir 300 mg/m2 from 14 days of life and 42 weeks postmenstrual age. We discontinued nevirapine 12 weeks after two consecutive plasma HIV-1 RNA levels below limit of detection. We tracked virological suppression, safety outcomes, and meeting a predetermined biomarker profile at age 2 years (undetectable RNA since week 48, HIV-1 antibody-negative, HIV-1 DNA not detected, and normal CD4 count and CD4 percentage) to assess qualification for analytical treatment interruption. This study is registered with ClinicalTrials.gov, NCT02140255.

FINDINGS

Between Jan 23, 2015, and Dec 14, 2017, 440 infants were included in cohort 1 and 20 were included in cohort 2. 54 of these infants (34 from cohort 1 and 20 from cohort 2) had confirmed in-utero HIV-1 and were enrolled to receive study ART. 33 (61%) of 54 infants were female and 21 (39%) were male. The estimated probability of maintaining undetectable plasma RNA through to 2 years was 33% (95% CI 17-49) in cohort 1 and 57% (28-78) in cohort 2. Among infants maintaining protocol-defined virological control criteria through to study week 108, seven of 11 (64%, 95% CI 31-89) in cohort 1 and five of seven (71%, 29-96) in cohort 2 had no detected HIV-1 DNA. Ten of 12 (83%, 52-100) in cohort 1 and all seven (100%, 59-100) in cohort 2 tested HIV-1 antibody-negative at week 108. Among 54 infants initiated on very early ART, ten (19%; six in cohort 1 and four in cohort 2) met all criteria for possible analytical treatment interruption. Reversible grade 3 or 4 adverse events occurred in 15 (44%) of 34 infants in cohort 1 and seven (35%) of 20 infants in cohort 2.

INTERPRETATION

Very early ART for in-utero HIV-1 can achieve sustained virological suppression in association with biomarkers indicating restricted HIV-1 reservoirs by age 2 years, which might enable potential ART-free remission.

FUNDING

National Institute of Allergy and Infectious Diseases, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, and the National Institute of Mental Health.

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.

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.

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.

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.

Steady-state pharmacokinetics of plasma tenofovir alafenamide (TAF), tenofovir (TFV) and emtricitabine (FTC), and intracellular TFV-diphosphate and FTC-triphosphate in HIV-1 infected old Japanese patients treated with bictegravir/FTC/TAF

Emtricitabine (FTC) plus tenofovir alafenamide (TAF) has demonstrated efficacy and safety for pre-exposure prophylaxis (PrEP) to prevent HIV-1 infection. We measured the plasma PK of FTC, tenofovir (TFV), and TAF in a steady-state pharmacokinetic (PK) study of bictegravir/FTC/TAF in HIV-1-infected patients. Furthermore, validated liquid chromatography-tandem mass spectrometry was used to measure intracellular TFV-diphosphate (DP) and FTC-triphosphate (TP), the active metabolites of TFV and FTC, respectively. Plasma and dried blood spot samples were collected from 10 male patients aged ≥ 50 years at various time intervals: 0 (trough), 1, 2, 3, 4, 6, 8, 12, and 24 h after drug administration. The mean ± standard deviation of plasma PK parameters were as follows: The maximum concentrations of TAF, TFV, and FTC were 104.0 ± 72.5, 27.9 ± 5.2, and 3,976.0 ± 683.6 ng/mL, respectively. Additionally, their terminal elimination half-lives were 0.6 ± 0.5, 31.6 ± 10.4, and 6.9 ± 1.4 h, respectively. These results were consistent with previously reported data. The intracellular levels of TFV-DP and FTC-TP varied widely among individuals; however, they remained stable over 24 h in each individual at approximately 1,000-1,500 and 2,000-3,000 fmol/punch, respectively, indicating that plasma concentrations did not affect the intracellular concentrations of their active metabolites. These results demonstrated that measuring intracellular TFV-DP and FTC-TP could be useful for monitoring adherence to PrEP in clients on this regimen.

Comparing Predictive Ability of Two Objective Adherence Measures in a Community-Based Cohort on Antiretroviral Therapy in South Africa: Tenofovir Diphosphate Concentrations and Electronic Adherence Monitors

BACKGROUND

Electronic adherence (EA) and tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) are objective measures of antiretroviral therapy (ART) adherence. We characterized the association between these measures in a prospective cohort of persons with HIV (PWH) on ART.

SETTING

Four primary health clinics in Cape Town, South Africa.

METHODS

We enrolled 250 virally suppressed PWH receiving tenofovir-based ART. We collected EA data, monthly viral load, and TFV-DP in DBS for 12 months. We used logistic regression to estimate the adjusted odds ratio (aOR) and 95% confidence intervals (CIs) for future viral breakthrough (VB) (>400 copies/mL) for each adherence measure. Receiver operating characteristics (ROCs) provided the predictive power of these measures.

RESULTS

Participants had a median (IQR) age of 34 (27-42); 78% were women. Twenty-one (8%) developed VB. Logistic regression showed that when percent EA and TFV-DP concentrations increased, the odds of VB decreased. This relationship was consistent at the time of VB (aOR of 0.41 [95% CI: 0.25 to 0.66] for TFV-DP and aOR of 0.64 [95% CI: 0.54 to 0.76] for EA) and for up to 2 months before VB. Both adherence measures predicted future VB at both 1 month and 2 months before viral load measurement.

CONCLUSION

We established that 2 objective adherence measures, EA and TFV-DP in DBS, have a positive association with, and are both strongly predictive of, VB in a community-based South African cohort on ART. Future research is needed to determine the feasibility of implementing these adherence measures in resource-limited settings to facilitate adherence interventions.

Determinants of adherence to daily PrEP measured as intracellular tenofovir diphosphate concentrations over 24 months of follow-up among men who have sex with men

OBJECTIVES

Adherence is key to the effectiveness of oral pre-exposure prophylaxis (PrEP) to prevent HIV. Therefore, we aimed to explore factors associated with adherence to daily PrEP (dPrEP).

METHODS

Men who have sex with men (MSM) using dPrEP (emtricitabine/tenofovir disoproxil) within the Amsterdam PrEP demonstration project at the Public Health Service of Amsterdam, provided dried blood spots (DBS) 12 and 24 months after PrEP initiation. From DBS, we determined intracellular tenofovir diphosphate (TFV-DP) concentrations to assess adherence; TFV-DP ≥700 fmol/punch was considered adequate. We assessed associations of sociodemographic, clinical and behavioural characteristics with TFV-DP concentrations using multivariable linear regression.

RESULTS

Of 263 participants who attended 12-month or 24-month study visits while on dPrEP, 257 (97.7%) provided DBS at one or both visits (492 DBS in total). Median TFV-DP concentration was 1299 (IQR 1021-1627) fmol/punch (12 months: 1332 (1087-1687); 24 months: 1248 (929-1590]). Higher TFV-DP concentrations were associated with: older age (p=0.0008), condomless anal sex with a casual partner in 6 months preceding PrEP initiation (+166 fmol/punch; 95% CI 36.5 to 296) and using a mobile application providing visualised feedback on PrEP use and sexual behaviour (+146 fmol/punch; 95% CI 28.1 to 263). Lower TFV-DP concentrations were associated with longer duration of PrEP use (24 vs 12 months; -91.5 fmol/punch; 95% CI -155 to -28.1). Time-updated number of sex partners, diagnosed STIs and chemsex were not associated with TFV-DP concentrations.

CONCLUSIONS

Overall, TFV-DP concentrations were high among MSM using dPrEP, indicating excellent adherence. Especially older participants, those who reported condomless anal sex with a casual partner prior to PrEP initiation and those who used an app with visualised feedback showed higher levels of adherence. As TFV-DP concentrations had decreased slightly at 2 years of PrEP use when compared with 1 year, we emphasise the importance of adherence counselling to those who continue using PrEP.

TRIAL REGISTRATION NUMBER

NL5413.

Food Insecurity Is Associated With Low Tenofovir Diphosphate in Dried Blood Spots in South African Persons With HIV

Background

Food insecurity has been linked to suboptimal antiretroviral therapy (ART) adherence in persons with HIV (PWH). This association has not been evaluated using tenofovir diphosphate (TFV-DP) in dried blood spots (DBSs), a biomarker of cumulative ART adherence and exposure.

Methods

Within a prospective South African cohort of treatment-naive PWH initiating ART, a subset of participants with measured TFV-DP in DBS values was assessed for food insecurity status. Bivariate and multivariate median-based regression analysis compared the association between food insecurity and TFV-DP concentrations in DBSs adjusting for age, sex, ethnicity, medication possession ratio (MPR), and estimated glomerular filtration rate.

Results

Drug concentrations were available for 285 study participants. Overall, 62 (22%) PWH reported worrying about food insecurity and 44 (15%) reported not having enough food to eat in the last month. The crude median concentrations of TFV-DP in DBSs differed significantly between those who expressed food insecurity worry versus those who did not (599 [interquartile range {IQR}, 417-783] fmol/punch vs 716 [IQR, 453-957] fmol/punch; P = .032). In adjusted median-based regression, those with food insecurity worry had concentrations of TFV-DP that were 155 (95% confidence interval, -275 to -35; P = .012) fmol/punch lower than those who did not report food insecurity worry. Age and MPR remained significantly associated with TFV-DP.

Conclusions

In this study, food insecurity worry is associated with lower TFV-DP concentrations in South African PWH. This highlights the role of food insecurity as a social determinant of HIV outcomes including ART failure and resistance.

Application of novel plasma separation filter cards for quantification of nucleoside/nucleotide reverse transcriptase inhibitor di/triphosphates in dried blood spots using LC-MS

Background: A rapid and sensitive LC-MS method has been developed and validated for the quantification of nucleoside di/triphosphates using a novel plasma separation card (HemaSep). Materials & methods: Cards were spotted with whole blood and stored at -80°C. Metabolites were extracted using 70:30 MeOH:20% formic acid, followed by weak anion exchange SPE and eluted using a Biobasic-AX column. Quantification was performed using a triple quadrupole mass spectrometer with a calibration range of 1.25-250 pmol/sample. Results: The recovery of metabolites was high (>93%). Precision and accuracy were acceptable and metabolites remained stable on the card after 29 days (stored at ambient temperature). Conclusion: HemaSep dried blood spots are a useful microsampling tool and offer an alternative to liquid plasma as they maintain stability over time.

Estradiol and Spironolactone Plasma Pharmacokinetics Among Brazilian Transgender Women Using HIV Pre-Exposure Prophylaxis: Analysis of Potential Interactions

BACKGROUND AND OBJECTIVE

An important barrier to HIV prevention among transgender women (TGW) is the concern that oral pre-exposure prophylaxis (PrEP) negatively affects the efficacy of feminizing hormone therapy (FHT). We aimed to assess the impact of PrEP on FHT pharmacokinetics (PK) among TGW from Brazil.

METHODS

We performed a drug-drug interaction sub-study among TGW enrolled in a daily oral PrEP demonstration study (PrEParadas, NCT03220152). Participants had a first PK assessment (PK1) 15 days after FHT (estradiol valerate 2-6 mg plus spironolactone 100-200 mg) initiation and then started PrEP (tenofovir disoproxil fumarate 300 mg/emtricitabine 200 mg). A second PK evaluation was performed 12 weeks later (PK2). Blood samples were collected prior and after the directly observed dosing (0, 0.5, 1, 2, 4, 6, 8, and 24 hours). Pharmacokinetic parameters of estradiol, spironolactone, and metabolites were estimated by non-compartmental analysis (Monolix 2021R2, Lixoft®) and compared as geometric mean ratios (GMRs, 90% confidence interval [CI]).

RESULTS

Among 19 TGW who completed the substudy, median age was 26 years (interquartile range: 23-27.5). Estradiol area under the plasma concentration-time curve (AUCτ) and trough concentrations did not differ between PK1 and PK2 evaluations (GMR [90% CI]: 0.89 [0.76-1.04] and 1.06 [0.94-1.20], respectively). Spironolactone and canrenone AUCτ were statistically lower at PK2 than PK1 (0.76 [0.65-0.89] and 0.85 [0.78-0.94], respectively). Canrenone maximum concentration was also lower at PK2 than PK1 (0.82 [0.74-0.91]).

CONCLUSION

Estradiol PK was not influenced by PrEP concomitant use. The small differences observed in some spironolactone and canrenone PK parameters should not prevent the concomitant use of estradiol-based FHT and PrEP.

TRIAL REGISTRATION

This trial (NCT03220152) was registered on July 18, 2017.

Application of the multiphase optimisation strategy (MOST) to optimise HIV prevention targeting people on medication for opioid use disorder (MOUD) who have cognitive dysfunction: protocol for a MOST study

INTRODUCTION

People who inject drugs (PWID) have remained a contributor to the consistent HIV incidence rates in the US for decades. Pre-exposure prophylaxis (PrEP) is a promising biomedical intervention for HIV prevention among individuals at risk for HIV infection, including PWID. However, PWID report the lowest rates of PrEP uptake and adherence among at-risk groups. Tailored HIV prevention interventions must include strategies that compensate for cognitive dysfunction among PWID.

METHODS AND ANALYSIS

Using the multiphase optimisation strategy, we will be conducting a 16-condition factorial experiment to investigate the effects of four different accommodation strategy components to compensate for cognitive dysfunction among 256 PWID on medication for opioid use disorder. This innovative approach will inform optimisation of a highly effective intervention to enhance PWID's ability to process and utilise HIV prevention content to improve PrEP adherence and HIV risk reduction in a drug treatment setting.

ETHICS AND DISSEMINATION

The institutional review board at the University of Connecticut approved this protocol (H22-0122) with an institutional reliance agreement with APT Foundation Inc. All participants are required to sign an informed consent form prior to engaging in any study protocols. The results of this study will be disseminated on national and international platforms through presentations at major conferences and journals.

TRIAL REGISTRATION NUMBER

NCT05669534.

Development and validation of an LC-MS/MS method to quantify the alcohol biomarker phosphatidylethanol 16:0/18:1 in dried blood spots for clinical research purposes

Phosphatidylethanol (PEth) is a group of phospholipids detectable in red blood cells exclusively following ethanol consumption. The primary PEth analog, PEth 16:0/18:1, has an extended half-life in red cells, providing a long window of detection and tremendous potential for the quantification of cumulative alcohol consumption. We developed and validated an LC/MS-MS method to quantify PEth 16:0/18:1 in dried blood spots (DBS) for clinical research purposes. Method development and validation followed FDA guidance but expanded on prior published methods through the evaluation of additional DBS-specific factors such as sample hematocrit, punch location, and spot volume. This method was applied to the quantification of PEth in participant samples.

Viral and Host Mediators of Non-Suppressible HIV-1 Viremia

Non-suppressible HIV-1 viremia (NSV) can occur in persons with HIV despite adherence to combination antiretroviral therapy (ART) and in the absence of significant drug resistance. Here, we show that plasma NSV sequences are comprised primarily of large clones without evidence of viral evolution over time. We defined proviruses that contribute to plasma viremia as "producer", and those that did not as "non-producer". Compared to ART-suppressed individuals, NSV participants had a significantly larger producer reservoir. Producer proviruses were enriched in chromosome 19 and in proximity to the activating H3K36me3 epigenetic mark. CD4+ cells from NSV participants demonstrated upregulation of anti-apoptotic genes and downregulation of pro-apoptotic and type I/II interferon-related pathways. Furthermore, NSV participants showed no elevation in HIV-specific CD8+ cell responses and producer proviruses were enriched for HLA escape mutations. We identified critical host and viral mediators of NSV that represent potential targets to disrupt HIV persistence and promote viral silencing.

Effectiveness and Safety of Bictegravir/Emtricitabine/Tenofovir Alafenamide in Patients With HIV-1 Infection and Ongoing Substance Use Disorder: The BASE Study

Background

People with human immunodeficiency virus (HIV) and substance use disorder (PWH/SUD) are at higher risk of nonadherence to antiretroviral therapy. Bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) exhibits high rates of efficacy with a favorable adverse event profile. The BASE study (NCT03998176) is a phase 4, single-arm study evaluating the effectiveness and safety of B/F/TAF among PWH/SUD.

Methods

Viremic (HIV RNA >1000 copies/mL) PWH/SUD initiated B/F/TAF once daily for 48 weeks (W). The primary endpoint was proportion of participants with HIV RNA <50 copies/mL at W24. Secondary endpoints were proportion of participants with HIV-1 RNA <50 copies/mL at W48, safety, B/F/TAF adherence (dried blood spot [DBS] concentrations of emtricitabine triphosphate and tenofovir diphosphate [TFV-DP]), substance use (NIDA-ASSIST), and quality of life (SF-12).

Results

Forty-three participants were enrolled; 95% reported methamphetamine use. Median age was 38 (range, 21-62) years; 21% were female, 81% White, 14% Black, and 16% Hispanic. Thirty-two (74%) and 21 (49%) participants had HIV RNA <50 copies/mL (intention-to-treat) at W24 and W48, respectively. Seven participants (16%) experienced confirmed virologic failure through W48; 1 developed emergent drug resistance (M184V). Fifteen participants (35%) experienced grade ≥3 adverse events. Five participants (12%) reported suicidal ideation; none resulted in discontinuation. Median DBS concentrations were representative of 5-6 doses/week (TFV-DP, 1603 fmol/punches). NIDA-ASSIST scores declined from baseline to W48 with methamphetamine use decreasing most (-7.9 points; -29%), and SF-12 physical/mental scores increased 1.2 and 7.6 points, respectively.

Conclusions

B/F/TAF among a high-risk population of PWH/SUD resulted in an initial 72% viral suppression rate at W24 before dropping to 49% at W48 as retention declined. One participant developed emergent drug resistance (M184V).

Randomized Controlled Trial of Automated Directly Observed Therapy for Measurement and Support of PrEP Adherence Among Young Men Who have Sex with Men

Measurement of adherence to oral pre-exposure prophylaxis (PrEP) in real-time has been challenging. We developed DOT Diary, a smartphone application that combines automated directly observed therapy with a PrEP adherence visualization toolkit, and tested its ability to measure PrEP adherence and to increase adherence among a diverse cohort of young men who have sex with men (MSM). We enrolled 100 MSM in San Francisco and Atlanta and randomly assigned them 2:1 to DOT Diary versus standard of care. Concordance between DOT Diary measurement and drug levels in dried blood spots was substantial, with 91.0% and 85.3% concordance between DOT Diary and emtricitabine-triphosphate and tenofovir-diphosphate, respectively. There was no significant difference in the proportion of participants with detectable PrEP drug levels at 24 weeks between study arms. These results suggest DOT Diary is substantially better than self-reported measures of adherence, but additional interventions are needed to improve PrEP adherence over time.

Clinic-Integrated Mobile Health Intervention ("JomPrEP" App) to Improve Uptake of HIV Testing and Pre-exposure Prophylaxis Among Men Who Have Sex With Men in Malaysia: Protocol for an Intervention Development and Multiphase Trial

BACKGROUND

Men who have sex with men (MSM) are disproportionately affected by the HIV epidemic in Malaysia and globally. Cross-cutting prevention strategies such as mobile health (mHealth), particularly smartphone apps, hold great promise for HIV prevention efforts among Malaysian MSM, especially when linked to HIV testing and pre-exposure prophylaxis (PrEP).

OBJECTIVE

This study aims to adapt an existing app to create and test a clinic-integrated app (JomPrEP), a virtual platform to deliver HIV testing and PrEP services for MSM in Malaysia.

METHODS

The JomPrEP project involves developing and testing an app-based platform for HIV prevention among Malaysian MSM and will be conducted in 2 phases. In phase I (development phase), we will adapt an existing mHealth app (HealthMindr) to create a new clinic-integrated app called "JomPrEP" to deliver holistic HIV prevention services (eg, HIV testing, PrEP, support services for mental health and substance use) among MSM in Malaysia. During phase II (testing phase), we will use a type I hybrid implementation science trial design to test the efficacy of JomPrEP while gathering information on implementation factors to guide future scale-up in real-world settings.

RESULTS

As of September 2022, we have completed phase I of the proposed study. Based on a series of formative work completed during phase I, we developed a fully functional, clinic-integrated JomPrEP app, which provides a virtual platform for MSM in Malaysia to facilitate their engagement in HIV prevention in a fast and convenient manner. Based on participant feedback provided during phase I, we are currently optimizing JomPrEP and the research protocols for a large-scale efficacy trial (phase II), which will commence in January 2023.

CONCLUSIONS

Scant HIV prevention resources coupled with entrenched stigma, discrimination, and criminalization of same-sex sexual behavior and substance use hamper access to HIV prevention services in Malaysia. If found efficacious, JomPrEP can be easily adapted for a range of health outcomes and health care delivery services for MSM, including adaptation to other low- and middle-income countries.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05325476; https://clinicaltrials.gov/ct2/show/NCT05325476.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/43318.

Adherence challenges with daily oral pre-exposure prophylaxis during pregnancy and the postpartum period in South African women: a cohort study

INTRODUCTION

Daily oral pre-exposure prophylaxis (PrEP) can reduce HIV acquisition. However, prevention effectiveness requires daily adherence prior to and during periods of sexual activity. Little is known about pharmacologic measures of PrEP adherence during pregnancy and postpartum and the factors related to optimal adherence during periods of sexual activity in this population.

METHODS

Between August 2019 and October 2021, we enrolled pregnant women without HIV at their first antenatal care visit followed-up through 12 months postpartum. Eligible women ≥16 years old received HIV prevention counselling and were offered oral PrEP (TDF-FTC). We quantified tenofovir-diphosphate (TFV-DP) in dried blood spots in women who reported taking PrEP in the past 30 days (at quarterly follow-up visits). We used regression models with generalized estimating equations to evaluate correlates of TFV-DP (any vs. none, and ≥2 vs. <2 doses/week), adjusting for maternal age and pregnancy status.

RESULTS AND DISCUSSION

In 382 women who started PrEP in pregnancy, returned for follow-up and reported PrEP use in the past 30 days, the median age was 27 years (interquartile range [IQR] = 23-32), and the median time on PrEP was 168 days (IQR = 84-252 days). Half of the samples had quantifiable TFV-DP at any time point (52%), declining from 67% of pregnant women 3 months post-initiation to 31% of postpartum women by 12 months. Overall, 72% had concentrations corresponding to <2 doses/week; 25% ≥2 doses/week; 3% 7 doses/week. Concentrations were lower in postpartum versus pregnancy (age-adjusted odds ratio [aOR] = 0.44; 95% confidence interval [CI] = 0.35-0.54). The correlation of self-reported adherence and TFV-DP ranged from -0.07 in pregnancy to 0.25 in postpartum women. Variables associated with having quantifiable TFV-DP included partner living with HIV/unknown serostatus (aOR = 1.50; 95% CI = 1.01-2.22), and reported frequency of sexual activity in the past month (aOR sex >5/month vs. no sex or <5 times/month = 2.11; 95% CI = 1.58-2.82) adjusting for age and pregnancy versus postpartum status. TFV-DP concentrations declined over follow-up time (aOR for 6 vs. 3 months = 0.49; 95% CI = 0.36-0.67).

CONCLUSIONS

Objectively measured adherence to PrEP was low overall and did not correlate with self-reported use. There is an urgent need for objective adherence measures to support clinical decision-making as well as adherence support interventions as part of PrEP services for pregnant and postpartum women at risk of HIV.

Pharmacokinetics of Emtricitabine/Tenofovir Disoproxil Fumarate Among Transgender Adolescents and Young Adults Without HIV Receiving Gender Affirming Hormones

The transgender community has expressed concerns regarding drug-drug interactions between HIV-pre-exposure prophylaxis (PrEP) and gender-affirming hormones. In this study, we evaluated emtricitabine (F, FTC)/tenofovir (TFV) disoporoxil fumarate (TDF) pharmacokinetics (PK) among adolescent and young adult transgender persons receiving gender-affirming hormone therapy (GAHT). This was a prospective, observational study among transgender women (TW) and men (TM) without HIV, 15-24 years of age, receiving GAHT (estradiol with/without spironolactone, or testosterone). Participants received 1 month of directly observed daily F/TDF. Weekly convenience blood samples were collected for plasma TFV and FTC, and intracellular TFV-diphosphate (TFV-DP) and FTC-triphosphate (FTC-TP) in peripheral blood mononuclear cells (PBMC) and dried blood spots (DBS). After 2-3 weeks of F/TDF dosing, intensive PK sampling was conducted. PK parameters were estimated using noncompartmental methods. Data were log-transformed and compared between TM and TW, and to historical data among cisgender adults. Plasma TFV exposures were similar between TM and TW [geometric mean ratio (GMR); confidence interval (95% CI): 1.06 (0.89-1.28)], whereas FTC plasma exposures were 21% higher in TM versus TW (95% CI: 1.07-1.38). TFV-DP in PBMC and DBS and FTC-TP in DBS did not differ between TM versus TW after controlling for creatinine clearance (CrCl), but FTC-TP in PBMC remained 46% (95% CI: 1.15-1.86) higher in TM versus TW. All PK exposures were within expected ranges based on historical studies. TM had higher FTC exposures compared with TW, but overall plasma and intracellular exposures for both drugs were within the range of historical studies, suggesting high PrEP efficacy will be retained in adolescent and young adult transgender persons. Registered at ClinicalTrials.gov (NCT03652623).

Nurse Practitioner-Led Integrated Rapid Access to HIV Prevention for People Who Inject Drugs (iRaPID): Protocol for a Pilot Randomized Controlled Trial

BACKGROUND

The ongoing volatile opioid epidemic remains a significant public health concern, alongside continued outbreaks of HIV and hepatitis C virus among people who inject drugs. The limited access to and scale-up of medications for opioid use disorder (MOUD) among people who inject drugs, coupled with multilevel barriers to pre-exposure prophylaxis (PrEP) uptake, makes it imperative to integrate evidence-based risk reduction and HIV prevention strategies in innovative ways. To address this need, we developed an integrated rapid access to HIV prevention program for people who inject drugs (iRaPID) that incorporates same-day PrEP and MOUD for this population.

OBJECTIVE

The primary objective of this pilot study is to assess the feasibility and acceptability of the program and evaluate its preliminary efficacy on PrEP and MOUD uptake for a future randomized controlled trial (RCT). We also aim to explore information on the implementation of the program in a real-world setting using a type I hybrid implementation trial design.

METHODS

Using a type I hybrid implementation trial design, we are pilot testing the nurse practitioner-led iRaPID program while exploring information on its implementation in a real-world setting. Specifically, we will assess the feasibility and acceptability of the iRaPID program and evaluate its preliminary efficacy on PrEP and MOUD uptake in a pilot RCT. The enrolled 50 people who inject drugs will be randomized (1:1) to either iRaPID or treatment as usual (TAU). Behavioral assessments will occur at baseline, and at 1, 3, and 6 months. Additionally, we will conduct a process evaluation of the delivery and implementation of the iRaPID program to collect information for future implementation.

RESULTS

Recruitment began in July 2021 and was completed in August 2022. Data collection is planned through February 2023. The Institutional Review Boards at Yale University and the University of Connecticut approved this study (2000028740).

CONCLUSIONS

This prospective pilot study will test a nurse practitioner-led, integrated HIV prevention program that incorporates same-day PrEP and MOUD for people who inject drugs. This low-threshold protocol delivers integrated prevention via one-stop shopping under the direction of nurse practitioners. iRaPID seeks to overcome barriers to delayed PrEP and MOUD initiation, which is crucial for people who inject drugs who have had minimal access to evidence-based prevention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04531670; https://clinicaltrials.gov/ct2/show/NCT04531670.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/42585.

Impact of feminizing hormone therapy on tenofovir and emtricitabine plasma pharmacokinetics: a nested drug-drug interaction study in a cohort of Brazilian transgender women using HIV pre-exposure prophylaxis

OBJECTIVES

Potential interactions between feminizing hormone therapy (FHT) and pre-exposure prophylaxis (PrEP) may be a barrier to PrEP use among transgender women (TGW). We aimed to assess the impact of FHT on PrEP plasma pharmacokinetics (PK) among TGW.

METHODS

This was a PK substudy of the effects of FHT on tenofovir disoproxil fumarate/emtricitabine nested to a trans-specific PrEP demonstration study (NCT03220152). Participants were assigned to receive PrEP only (noFHT) or standardized FHT (sFHT; oestradiol valerate 2-6 mg plus spironolactone 100-300 mg) plus PrEP for 12 weeks, after which they could start any FHT (aFHT). Short- and long-term PK assessment occurred at Weeks 12 and 30-48, respectively (plasma samples prior and 0.5, 1, 2, 4, 6, 8 and 24 h after dose). Non-compartmental PK parameters of tenofovir and emtricitabine were compared as geometric mean ratios (GMRs) between noFHT and PrEP and FHT (sFHT at short-term PK; aFHT at long-term PK) participants.

RESULTS

No differences in tenofovir and emtricitabine plasma PK parameters were observed between the short-term PK of noFHT (n = 12) and sFHT participants (n = 18), except for emtricitabine Cmax [GMR: 1.15 (95% CI: 1.01-1.32)], or between noFHT short-term PK and aFHT long-term PK (n = 13). Most participants were on oestradiol valerate 2 mg at the short-term PK (56%) and 4 mg at the long-term PK (54%). Median (IQR) oestradiol levels were 56.8 (43.2-65.4) pg/mL at short-term PK (sFHT) and 44.8 (24.70-57.30) pg/mL at long-term PK (aFHT). No participants in this analysis seroconverted during the study.

CONCLUSIONS

Our results indicate no interaction of FHT on tenofovir levels, further supporting PrEP use among TGW using FHT.

Tenofovir-Diphosphate in Dried Blood Spots versus Tenofovir in Urine/Plasma for Oral Preexposure Prophylaxis Adherence Monitoring

Background

Tenofovir-diphosphate (TFV-DP) measured in dried blood spots (DBS) and tenofovir (TFV) measured in urine/plasma have been used to measure TFV-based oral pre-exposure prophylaxis (PrEP) adherence. However, there are limited data comparing these 3 metrics and their appropriate use for PrEP adherence monitoring.

Methods

We collected DBS, urine, and plasma samples from HIV-negative adults randomized to a low (2 doses/week), moderate (4 doses/week), or perfect (7 doses/week) adherence group (via directly observed therapy) of tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for 6 weeks, followed by a 4-week washout phase. Drug concentrations were measured using liquid chromatography tandem mass spectrometry. Linear mixed-effects modeling was used to examine associations between drug concentrations and dosing time.

Results

Among 28 participants, the median age was 33 years, and 12 (43%) were female. At steady state, 25th percentile TFV-DP concentrations were 466, 779, and 1375 fmol/3 mm punch in the low, moderate, and perfect adherence group, respectively. Correlation was stronger between quantifiable TFV-DP and plasma TFV (r = 0.65; P < .01) than between TFV-DP and urine TFV (r = 0.50; P < .01). Among all participants, each additional week of cumulative dosing on average led to a mean increase of 158 fmol/3 mm punch (P < .001) in TFV-DP during the dosing phase. Each additional day after the last dose was associated with 43 fmol/3 mm punch lower TFV-DP (P = .07).

Conclusions

TFV-DP levels in DBS provide valuable insight into both dosing recency and cumulative doses from variable adherence patterns. Our observed benchmark TFV-DP concentrations were slightly higher than prior predicted estimates based on convenience samples.

Cumulative tenofovir diphosphate exposure in persons with HIV taking single- vs. multiple-tablet regimens

BACKGROUND

We assessed cumulative antiretroviral exposure-using tenofovir diphosphate (TFV-DP) in dried blood spots (DBS)-in persons with HIV (PWH) receiving tenofovir disoproxil fumarate (TDF)-based antiretroviral therapy (ART) as single-tablet regimens (STR) or multiple-tablet regimens (MTR).

METHODS

Blood for DBS was prospectively collected in PWH on TDF during 1144 person visits (n = 523). Linear mixed-effects models, adjusted for baseline characteristics, were used to compare TFV-DP in STR versus MTR. Models adjusted for ART regimen using either anchor drug class, pharmacokinetic booster status (unboosted [u/] or boosted [b/]), or a combined STR/MTR and booster categorical variable.

RESULTS

In the anchor class-adjusted model, STR had 19% (95% confidence interval [CI]: 3%-37%; p = 0.02) higher TFV-DP concentrations than MTR. However, in the booster-adjusted model, STR was not significantly higher than MTR (estimate 5%, 95% CI: -9% to 21%; p = 0.48), although PWH on b/ART had 35% (95% CI: 16%-58%; p = 0.0001) higher TFV-DP than u/ART. In the STR/MTR-boosted variable model, when compared to u/MTR, b/STR, b/MTR, and u/STR had 25% (95% CI: 7%-47%; p = 0.005), 37% (95% CI: 17%-59%; p < 0.0001), and 7% (95% CI: -7% to 24%; p = 0.34) higher TFV-DP, respectively. Compared with b/MTR, b/STR had 9% (95% CI: -31% to 10%; p = 0.37) lower TFV-DP. In a sensitivity analysis of PWH with HIV viral load <20 copies/ml at all visits, b/STR and b/MTR had 34% (95% CI: 16%-55%; p < 0.0001) and 12% (95% CI: -2% to 27%; p = 0.09) higher TFV-DP, respectively, compared with u/MTR, while u/STR had 4% (95% CI: -15% to 8%; p = 0.50) lower TFV-DP. Compared with b/MTR, b/STR had 17% (95% CI: 2%-30%; p = 0.03) higher TFV-DP.

CONCLUSIONS

Persons with HIV on b/TDF-based ART had higher TFV-DP than u/ART, regardless of STR or MTR use. No significant differences in TFV-DP between regimens of the same boosting status (i.e., b/STR vs. b/MTR; u/STR vs. u/MTR) were observed in the full cohort. Future research should examine the clinical utility of these findings in patient-tailored ART selection.

Tenofovir diphosphate in dried blood spots predicts future viremia in persons with HIV taking antiretroviral therapy in South Africa

OBJECTIVES

Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) is used as a biomarker of antiretroviral therapy (ART) adherence. Recent treatment studies have shown that TFV-DP predicts future viremia in persons with HIV (PWH) but there are few data from high-burden settings. We investigated whether TFV-DP in DBS predicts future viral breakthrough in South African PWH.

DESIGN

Prospective observational cohort.

METHODS

We enrolled 250 adults receiving tenofovir-containing regimens, currently virally suppressed (<50 copies/ml) but at risk of future viral breakthrough, from four primary health clinics in Cape Town. Paired viral load and DBS for TFV-DP were collected monthly for 12 months. Viral breakthrough was the first confirmed viral load greater than 400 copies/ml. Logistic regression estimated the odds ratio (OR) and 95% confidence intervals for future viral breakthrough at the next visit.

RESULTS

Participants provided 2944 paired DBS and viral load samples. Median (IQR) age was 34 (27-42) years; median duration on ART at study entry was 11 (4-12) months;78% were women. Twenty-one (8%) participants developed viral breakthrough. Participants with TFV-DP 400 fmol/punch or less had an adjusted OR of 16.1 (95% CI: 3.9-67.4; P < 0.001) for developing viral breakthrough 1 month later compared with participants with TFV-DP greater 800 fmol/punch.

CONCLUSION

TFV-DP in DBS strongly predicted future viral breakthrough in a clinical cohort of South African PWH. A biomarker able to identify PWH at risk for future viral breakthrough has the potential to improve health outcomes through timely intervention. Future studies exploring the clinical use of TFV-DP in DBS in conjunction with viral load in ART monitoring are warranted.

HIV-1-infection in a man who has sex with men despite self-reported excellent adherence to pre-exposure prophylaxis, the Netherlands, August 2021: be alert to emtricitabine/tenofovir-resistant strain transmission

In August 2021, a man who has sex with men was diagnosed with HIV-1 infection despite using event-driven pre-exposure prophylaxis for over 2 years with self-reported excellent adherence. Sequencing identified resistance-associated mutations (RAM) M184V and K65R, conferring resistance to emtricitabine and tenofovir, and RAM V108I and E138A. Background RAM prevalence was two of 164 (1.2%) new HIV diagnoses in Amsterdam (2017–19). We reiterate the need for frequent HIV testing among PrEP users and additional testing in case of symptoms.

Low PrEP adherence despite high retention among transgender women in Brazil: the PrEParadas study

Introduction

We aimed to evaluate daily oral pre‐exposure prophylaxis (PrEP) uptake, retention, and adherence and predictors of study non‐attendance and low PrEP adherence in a Brazilian trans‐specific 48‐week study (PrEParadas).

Methods

We enrolled transgender women (TGW) engaging in high‐risk sexual behaviours between August 2017 and December 2018. PrEP adherence was based on tenofovir diphosphate concentrations in dried blood spots (DBS). We used random effects logistic regression models and ordinal models to estimate the odds of having a missed visit and of low PrEP adherence, respectively. Multivariable models were adjusted for variables with p‐value<0.10 in the univariate analysis.

Results

From the 271 eligible, 130 participants were enrolled in the study (PrEP uptake: 48%), out of which 111 (85.4%) were retained at 48 weeks. Multivariable model for study non‐attendance included study visit, age, main sexual partner and stimulant use. The odds of missing a visit increased after the week 24. Participants aged 18–24 (adjusted odds ratio [aOR] = 8.76, 95% CI: 2.09–36.7) and 25–34 years (aOR = 6.79, 95% CI: 1.72–26.8) compared to TGW aged 35+ years had significantly higher odds of having a missed visit. The odds of a missed visit were higher among participants reporting stimulant use (aOR = 4.99, 95% CI: 1.37–18.1) compared to no stimulant use. DBS levels at week 48 showed that 42 (38.5%), 14 (12.8%) and 53 (48.6%) of 109 participants had low, moderate and high PrEP adherence. Multivariable model for low PrEP adherence included study visit, age, schooling, race/colour, housing, binge drinking, stimulant use, feminizing hormone therapy (FHT) use and received text message. Low PrEP adherence was significantly higher among participants with less years of schooling (aOR = 6.71, 95% CI: 1.30–34.5) and had a borderline association with Black colour/race (aOR = 6.72, 95% CI: 0.94–47.8). Participants using the FHT available at the site had decreased odds of low PrEP adherence (aOR = 0.38, 95% CI: 0.16–0.88). No participant seroconverted over the course of the study.

Conclusions

Although high PrEP retention can be achieved in a gender‐affirming setting, PrEP adherence may be an important challenge faced among TGW due to social disparities. The scale‐up of prevention tools like PrEP will have to address systemic social determinants as these stand as important barriers for TGW's access to health services.

Understanding Pre-Exposure Prophylaxis Adherence in Young Women in Kenya

OBJECTIVE

To present detailed analyses of long-term pre-exposure prophylaxis (PrEP) use and associated behaviors and perceptions among young Kenyan women.

DESIGN

Prospective, observational cohort.

METHODS

The Monitoring PrEP among Young Adult women Study involved 18 to 24-year-old women at high HIV risk initiating PrEP in Kisumu and Thika, Kenya. Visits for PrEP counseling and dispensing, HIV testing, and socio-behavioral data collection occurred at Month 1 and quarterly for 2 years. PrEP adherence was measured with pharmacy refill and real-time electronic monitoring, plus tenofovir diphosphate levels in 15% of participants. HIV risk behavior and perception were assessed by self-report in weekly short message service surveys from Months 6-24. Predictors of adherence were assessed with multivariable logistic regression analysis.

RESULTS

Three hundred forty-eight women (median age 21, VOICE risk score 7) were followed for 617 person-years. Pharmacy refills steadily declined from 100% (Month 0-1) to 54% (Months 22-24). Average electronically monitored adherence similarly declined from 65% (Month 0-1) to 15% (Months 22-24). Electronically monitored adherence had moderately high concordance with tenofovir diphosphate levels (67%). High average adherence (5+ doses/week) was seen at 385/1898 (20%) participant-visits and associated with low baseline VOICE risk score, >1 current sexual partner, ≤1-hour travel time to clinic, and the Kisumu site. short message service-reported behavior and risk perception were not associated with adherence. Four women acquired HIV (incidence 0.7/100 person-years).

CONCLUSIONS

PrEP adherence was modest and declined over time. HIV risk was inconsistently associated with adherence; clinic access and site-level factors were also relevant. Relatively low HIV incidence suggests participants may have achieved protection through multiple strategies.

Tenofovir-diphosphate in peripheral blood mononuclear cells during low, medium and high adherence to emtricitabine/ tenofovir alafenamide vs. emtricitabine/ tenofovir disoproxil fumarate

OBJECTIVE

Tenofovir alafenamide (TAF) preferentially loads peripheral blood mononuclear cells (PBMCs), resulting in higher PBMC tenofovir-diphosphate (TFV-DP) vs. tenofovir disoproxil fumarate (TDF). No studies have yet compared TFV-DP in PBMC from lower than daily dosing between prodrugs, which has potential implications for event-driven preexposure prophylaxis and pharmacologic forgiveness.

DESIGN

Two separate randomized, directly observed therapy (DOT) crossover studies (DOT-DBS and TAF-DBS) were conducted to mimic low, medium and high adherence.

METHODS

HIV-negative adults were randomized to two 12-week DOT regimens of 33, 67 or 100% of daily dosing with emtricitabine (F)/TAF 200 mg/25 mg (TAF-DBS) or F/TDF 200 mg/300 mg (DOT-DBS), separated by a 12-week washout. PBMC steady-state concentrations (Css) of TFV-DP and FTC-TP were estimated using nonlinear mixed models and compared between F/TAF and F/TDF.

RESULTS

Thirty-five participants contributed to 33% (n = 23), 67% (n = 23) and 100% (n = 23) of daily F/TAF regimens. Forty-four contributed to 33% (n = 15), 67% (n = 16) and 100% (n = 32) of daily F/TDF regimens. PBMC TFV-DP Css were 7.3 [95% confidence interval (95% CI): 6.4-8.2], 7.1 (5.9-8.2) and 6.7- (4.4-8.9) fold higher (P < 0.0001) following F/TAF vs. F/TDF; 593 vs. 81.7, 407 vs. 57.4, and 215 vs. 32.3 fmol/106 cells, respectively. TFV-DP was 2.6 (2.1-3.1) fold higher with 33% F/TAF vs. 100% F/TDF. Estimated half-lives (95% CI) of TFV-DP in PBMC were 2.9 (1.5-5.5) days for F/TAF and 2.1 (1.5-2.9) days for F/TDF. FTC-TP was similar in both studies (P = 0.119).

CONCLUSION

F/TAF produced 6.7 to 7.3-fold higher TFV-DP in PBMC vs. F/TDF across adherence levels, supporting increased potency and pharmacologic forgiveness with F/TAF in the PBMC compartment.

Integration of pre-exposure prophylaxis services into public HIV care clinics in Kenya: a pragmatic stepped-wedge randomised trial

BACKGROUND

Successful and sustainable models for HIV pre-exposure prophylaxis (PrEP) delivery in public health systems in Africa are needed. We aimed to evaluate the implementation of PrEP delivery integrated in public HIV care clinics in Kenya.

METHODS

As part of Kenya's national PrEP roll-out, we conducted a stepped-wedge cluster-randomised pragmatic trial to catalyse scale-up of PrEP delivery integrated in 25 public HIV care clinics. We selected high-volume clinics in these regions (ie, those with a high number of people living with HIV enrolled in HIV care and treatment). Clinics (each representing a cluster) were stratified by region and randomly assigned to the order in which clinic staff would receive PrEP training and ongoing technical support using numbered opaque balls picked from a bag. There was no masking. PrEP provision was done by clinic staff without additional financial support. Data were abstracted from records of individuals initiating PrEP. The primary outcome was the number of people initiating PrEP per clinic per month comparing intervention to control periods. Other outcomes included PrEP continuation, adherence, and incident HIV infections. This trial is registered with ClinicalTrials.gov, NCT03052010.

FINDINGS

After the baseline period, which started in January, 2017, every month two to six HIV care clinics crossed over from control to intervention, until August, 2017, when all clinics were implementing the intervention. Of 4898 individuals initiating PrEP (27 during the control period and 4871 during the intervention period), 2640 (54%) were women, the median age was 31 years (IQR 25-39), and 4092 (84%) reported having a partner living with HIV. The mean monthly number of PrEP initiations per clinic was 0·1 (SD 0·5) before the intervention and 7·5 (2·7) after intervention introduction (rate ratio 23·7, 95% CI 14·2-39·5, p<0·0001). PrEP continuation was 57% at 1 month, 44% at 3 months, and 34% at 6 months, and 12% of those who missed a refill returned later for PrEP re-initiation. Tenofovir diphosphate was detected in 68 (96%) of 71 blood samples collected from a randomly selected subset of participants. Six HIV infections were observed over 2531 person-years of observation (incidence 0·24 cases per 100 person-years), three of which occurred at the first visit after PrEP initiation.

INTERPRETATION

We observed high uptake, reasonable continuation with high adherence, frequent PrEP restarts, and low HIV incidence. Integration of PrEP services within public HIV care clinics in Africa is feasible.

FUNDING

National Institute of Mental Health and Bill & Melinda Gates Foundation.

Tenofovir diphosphate levels in dried blood spots are associated with virologic failure and resistance to first-line therapy in South Africa: a case-control cohort study

INTRODUCTION

Tenofovir diphosphate (TFV-DP) in dried blood spots (DBS), a measure of cumulative antiretroviral therapy (ART) adherence, is associated with viral suppression and predicts future viremia in persons with HIV (PWH). However, its utility to identify those at risk for virologic failure (VF) and drug resistance is unknown. To address this, we aimed to establish the association between this adherence biomarker and VF with drug resistance in a cohort of PWH initiating first-line ART in KwaZulu-Natal, South Africa.

METHODS

PWH initiating TFV disoproxil fumarate (TDF)-based ART within a parent prospective cohort were evaluated. Using a nested design, DBS for TFV-DP were collected from cases who developed VF (HIV-1 RNA ≥1000 copies/ml) after ≥5 months on ART versus controls, matched 1:2 by site, age, gender, race and ART duration. Cases were categorized as having VF with or without resistance using genotyping. One-way analysis of variance (ANOVA) was used to compare TFV-DP for controls, cases with VF and resistance, and cases with VF without resistance. Data are presented as mean (standard deviation, SD) or geometric mean [95% confidence interval, 95% CI].

RESULTS AND DISCUSSION

One thousand participants were enrolled in the parent study between 2014 and 2016, of which 288 (29%) had DBS available. Of these, 94 (33%) were cases and 194 (67%) were controls; 59% were women. Mean age of our population was 33 (SD 8) years. Genotyping was available in 50 (53%) of the 94 cases. Geometric mean TFV-DP in DBS from controls was 708 [95% CI; 647-773] fmol/punch, which was higher compared to participants having VF with resistance (n = 36), 386 [95% CI; 241-617] fmol/punch and VF without resistance (n = 14), 61 [95% CI; 22-164] fmol/punch; p<0.001. Genotype could not be obtained in 44 (47%) cases.

CONCLUSIONS

TFV-DP in DBS showed a stepwise association with VF and drug resistance in South African PWH. Participants having VF with resistance had mid-range concentrations of TFV-DP, which were higher than those for PWH without resistance. Future research on the clinical utility of TFV-DP concentrations in DBS to predict and prevent the development of VF and drug resistance is needed.

Sex Hormone Therapy and Tenofovir Diphosphate Concentration in Dried Blood Spots: Primary Results of the Interactions Between Antiretrovirals And Transgender Hormones Study

BACKGROUND

Sex hormone and preexposure prophylaxis (PrEP) drug interactions among transgender women (TGW), transgender men (TGM), and cisgender men (CGM) are not fully understood.

METHODS

TGM and TGW on at least 6 months of stable sex hormone therapy containing testosterone or estradiol (respectively) were enrolled in a 4-week study of directly observed dosing of daily oral coformulated emtricitabine and tenofovir disoproxil fumarate (FTC/TDF). TFV-DP in dried blood spots and sex hormones in serum were measured at weekly intervals. TFV-DP was compared with 2- and 4-week samples from Directly Observed Therapy Dried Blood Spots (DOT-DBS) Study (NCT02022657).

RESULTS

From May 2017 to June 2018, 24 TGM and 24 TGW were enrolled. Testosterone (total and free) and estradiol concentrations were comparable before and after 4 weeks of PrEP use in TGM and TGW, respectively. Historical controls included 17 cisgender women (CGW) and 15 CGM. TFV-DP concentrations at week 4 were comparable between TGW and TGM (mean difference, -6%; 95% confidence interval [CI], -21% to 12%; P = .47), comparable between TGW and CGM (mean difference, -12%; 95% CI, -27% to 7%; P = .21) and were lower among TGM compared with CGW (mean difference, -23%; 95% CI, -36% to -7%; P = .007). All persons in all groups were projected to reach the TFV-DP threshold that has been associated with high protection from human immunodeficiency virus.

CONCLUSIONS

CGM, TGM, and TGW had comparable TFV-DP concentrations in dried blood spots after 4 weeks of directly observed daily FTC/TDF PrEP use. Serum hormone concentrations were not affected by FTC/TDF PrEP use.

CLINICAL TRIALS REGISTRATION

NCT04050371.

Emtricitabine triphosphate in dried blood spots predicts future viremia in persons with HIV and identifies mismatch with self-reported adherence

OBJECTIVE

Emtricitabine triphosphate (FTC-TP) in dried blood spots (DBS), a measure of short-term antiretroviral therapy (ART) adherence, is associated with viral suppression in persons with HIV (PWH). However, its ability to predict future viremia remains unknown.

DESIGN

Prospective, observational cohort (up to three visits in 48 weeks).

METHODS

PWH receiving TDF/FTC-based ART had DBS and HIV viral load obtained at routine clinical visits. FTC-TP in DBS was dichotomized into quantifiable vs. below the limit of quantification (BLQ). The adjusted odds ratio (aOR) of future viremia (≥20 copies/ml at next study visit) was estimated according to FTC-TP at the current visit. To assess for possible interactions, additional models adjusted for tenofovir diphosphate (TFV-DP) in DBS and 3-day self-reported adherence.

RESULTS

Data from 433 PWH (677 paired DBS/HIV viral load samples) were analyzed. The aOR [95% confidence interval (CI)] for future viremia for BLQ vs. quantifiable FTC-TP was 3.4 (1.8--6.5; P = 0.0002). This diminished after adjusting for TFV-DP [aOR 1.9 (0.9--4.1); P = 0.090]. Among PWH reporting 100% 3-day adherence, the odds of future viremia were 6.0 times higher [(1.8--20.3); P = 0.001] when FTC-TP was BLQ vs. quantifiable. Among participants (n = 75) reporting less than 100% adherence, BLQ FTC-TP in DBS was not predictive of future viremia [aOR 1.3 (0.4--4.6); P = 0.96].

CONCLUSION

Nonquantifiable FTC-TP in DBS predicts future viremia and is particularly informative in PWH reporting perfect adherence. As point-of-care adherence measures become available, mismatches between objective and subjective measures, such as FTC-TP in DBS and self-report, could help clinicians identify individuals at an increased risk of future viremia.

A comparison of covariate selection techniques applied to pre-exposure prophylaxis (PrEP) drug concentration data in men and transgender women at risk for HIV

Pre-exposure prophylaxis (PrEP) containing antiretrovirals tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide (TAF) can reduce the risk of acquiring HIV. Concentrations of intracellular tenofovir-diphosphate (TFV-DP) measured in dried blood spots (DBS) have been used to quantify PrEP adherence; although even under directly observed dosing, unexplained between-subject variation remains. Here, we wish to identify patient-specific factors associated with TFV-DP levels. Data from the iPrEX Open Label Extension (OLE) study were used to compare multiple covariate selection methods for determining demographic and clinical covariates most important for drug concentration estimation. To allow for the possibility of non-linear relationships between drug concentration and explanatory variables, the component selection and smoothing operator (COSSO) was implemented. We compared COSSO to LASSO, a commonly used machine learning approach, and traditional forward and backward selection. Training (N = 387) and test (N = 166) datasets were utilized to compare prediction accuracy across methods. LASSO and COSSO had the best predictive ability for the test data. Both predicted increased drug concentration with increases in age and self-reported adherence, the latter with a steeper trajectory among Asians. TFV-DP reductions were associated with increasing eGFR, hemoglobin and transgender status. COSSO also predicted lower TFV-DP with increasing weight and South American countries. COSSO identified non-linear relationships between log(TFV-DP) and adherence, weight and eGFR, with differing trajectories for some races. COSSO identified non-linear log(TFV-DP) trajectories with a subset of covariates, which may better explain variation and enhance prediction. Future research is needed to examine differences identified in trajectories by race and country.

Low-Level Viremia Is Associated With Cumulative Adherence to Antiretroviral Therapy in Persons With HIV

The drivers of low-level viremia (LLV) between 20 and 200 copies/mL remain unclear. In 1042 person-visits from 497 persons with HIV on tenofovir disoproxil fumarate-containing antiretroviral therapy (ART), the association between LLV and cumulative antiretroviral adherence (quantified using tenofovir diphosphate [TFV-DP] in dried blood spots) was assessed. Lower TFV-DP levels were associated with higher odds of LLV. As TFV-DP (fmol/punch) categories decreased from >1650 to 800-1650; 800-1650 to <800; and >1650 to <800, the adjusted odds ratios for LLV vs HIV VL <20 copies/mL were 2.0 (95% CI, 1.2-3.1), 2.4 (95% CI, 1.1-5.0), and 4.6 (95% CI, 2.2-9.9), respectively. This suggests that adherence could impact LLV.

Improving adherence to daily preexposure prophylaxis among MSM in Amsterdam by providing feedback via a mobile application

OBJECTIVE

Improving adherence to preexposure prophylaxis (PrEP) by providing automated feedback on self-reported PrEP use via a mobile application (app).

DESIGN

Randomized clinical trial among MSM participating in the Amsterdam PrEP demonstration project (AMPrEP).

METHODS

Eligible participants were randomized 1 : 1 to the control or intervention app. Both allowed daily reporting of sexual behaviour and medication intake; the intervention app also provided visual feedback. Dried blood spots collected at 12 and 24 months yielded intracellular tenofovir diphosphate concentrations (TFV-DP). We assessed proportions of participants with poor (TFV-DP <700 fmol/punch; primary outcome), good (TFV-DP ≥700 fmol/punch) and excellent (TFV-DP ≥1250 fmol/punch; secondary outcome) adherence at both time-points, and the association with the control or intervention app.

RESULTS

We randomized 229 participants, 118 to the intervention and 111 to the control arm. The primary, per-protocol, analysis included 83 participants per arm. In total, 22/166 (13%) of participants adhered poorly, 144/166 (87%) good and 66/166 (40%) excellently. App feedback did not result in a lower proportion of participants with poor adherence [control: 9 of 83 (11%); intervention: 13 of 83 (16%); P = 0.36]. App feedback did result in a larger proportion of participants with excellent adherence [control: 26/83 (31%); intervention: 40/83 (48%); P = 0.026].

CONCLUSION

In this highly adherent population, app feedback did not improve the proportion of participants with poor adherence to PrEP.Clinical Trial Number Netherlands Trial Register: NL5413.

Estimated pill intake with on-demand PrEP with oral TDF/FTC using TFV-DP concentration in dried blood spots in the ANRS IPERGAY trial

BACKGROUND

Tenofovir diphosphate (TFV-DP) concentration in dried blood spots (DBSs) is a reliable pharmacokinetics biomarker of adherence to tenofovir disoproxil fumarate (TDF). We aimed to use DBSs to estimate pill intake among participants using on-demand pre-exposure prophylaxis (PrEP) and to identify predictive factors associated with higher TFV-DP concentrations.

METHODS

DBSs were collected at the last study visit of the open-label phase of the ANRS IPERGAY study, assessing on-demand oral TDF/emtricitabine for PrEP among MSM and transgender female participants. We quantified TFV-DP in DBSs centrally. We assessed correlation between pill count and TFV-DP concentration by Spearman correlation and explored associations between participant demographics, sexual behaviour and PrEP use during sexual intercourse (SI) with TFV-DP concentrations by univariate and multivariate logistic regression models.

RESULTS

The median age of the 245 participants included in this study was 40 years, with a median body weight of 73 kg. Median (IQR) TFV-DP concentration reached 517 (128-868) fmol/punch, corresponding to an estimated intake of 8-12 tablets per month (2-3 doses per week). Only 39% of participants had a TFV-DP concentration above 700 fmol/punch. TFV-DP concentrations were moderately correlated with pill count (r: 0.59; P < 0.001). In multivariate analysis, only systematic use of PrEP during SI and more frequent episodes of SI in the past 4 weeks were significantly associated with higher TFV-DP levels [OR (95% CI): 11.30 (3.62-35.33) and 1.46 (1.19-1.79), respectively; P < 0.001].

CONCLUSIONS

Among participants using on-demand PrEP, estimated pill intake reached 8-12 tablets per month and was correlated with frequency and systematic use of PrEP for SI.

High Prevalence of NRTI and NNRTI Drug Resistance Among ART-Experienced, Hospitalized Inpatients

BACKGROUND

Patients hospitalized with advanced HIV have a high mortality risk. We assessed viremia and drug resistance among differentiated care services and explored whether expediting the switching of failing treatments may be justified.

SETTING

Hospitals in the Democratic Republic of (DRC) Congo (HIV hospital) and Kenya (general hospital including HIV care).

METHODS

Viral load (VL) testing and drug resistance (DR) genotyping were conducted for HIV inpatients ≥15 years, on first-line antiretroviral therapy (ART) for ≥6 months, and CD4 ≤350 cells/µL. Dual-class DR was defined as low-, intermediate-, or high-level DR to at least 1 nucleoside reverse transcriptase inhibitor and 1 non-nucleoside reverse transcriptase inhibitor. ART regimens were considered ineffective if dual-class DR was detected at viral failure (VL ≥1000 copies/mL).

RESULTS

Among 305 inpatients, 36.7% (Kenya) and 71.2% (DRC) had VL ≥1000 copies/mL, of which 72.9% and 73.7% had dual-class DR. Among viral failures on tenofovir disoproxil fumarate (TDF)-based regimens, 56.1% had TDF-DR and 29.8% zidovudine (AZT)-DR; on AZT regimens, 71.4% had AZT-DR and 61.9% TDF-DR, respectively. Treatment interruptions (≥48 hours during past 6 months) were reported by 41.7% (Kenya) and 56.7% (DRC). Approximately 56.2% (Kenya) and 47.4% (DRC) on TDF regimens had tenofovir diphosphate concentrations <1250 fmol/punch (suboptimal adherence). Among viral failures with CD4 <100 cells/µL, 76.0% (Kenya) and 84.6% (DRC) were on ineffective regimens.

CONCLUSIONS

Many hospitalized, ART-experienced patients with advanced HIV were on an ineffective first-line regimen. Addressing ART failure promptly should be integrated into advanced disease care packages for this group. Switching to effective second-line medications should be considered after a single high VL on non-nucleoside reverse transcriptase inhibitor-based first-line if CD4 ≤350 cells/µL or, when VL is unavailable, among patients with CD4 ≤100 cells/µL.

Short Communication: A Descriptive Analysis of Dried Blood Spot Adherence Testing Among Ugandans with HIV Presenting with Cryptococcal Meningitis

Early antiretroviral therapy (ART) initiation after cryptococcal meningitis increases mortality, and those unmasking cryptococcosis after <2 weeks of ART have higher mortality. However, it is unknown if those presenting as ART experienced are actually adherent to their ART. Unknowingly, restarting ART in persons, who have discontinued ART, may be a fatal iatrogenic error. To evaluate ART adherence in an exploratory analysis, we collected dried blood spots on 44 HIV-infected persons presenting with cryptococcal meningitis. We quantified tenofovir diphosphate (TFV-DP) and lamivudine (3TC) from dried blood spots. We quantified cumulative ART adherence over the preceding 6-8 weeks based on TFV-DP concentrations and adherence over the last few days based on 3TC concentrations. Of 22 ART experienced, 20 (91%) had quantifiable concentrations. Of 18 receiving tenofovir, 15 (83%) had TFV-DP consistent with drug intake of ≥4 doses/week or moderate adherence. With 3TC, 72% (18/22) had detectable levels consistent with adherence over the last 3 days before measurement. Only three ART-experienced subjects were alive and virally suppressed at 4 months (n = 2 on ART for <30 days; n = 1 with undetectable antiretrovirals). Surprisingly, of 22 who reported not receiving ART, 4 (18%) had quantifiable tenofovir. Most ART-experienced subjects were taking their ART with moderate to good adherence with the majority likely having viral resistance given generally at good ART levels, receipt of intensive adherence counseling, and lack of subsequent viral suppression. The World Health Organization (WHO) guidelines recommend adherence counseling with ART continuation and repeat viral loads in 1-3 months before switching to second-line ART. These recommendations are likely inappropriate in those with central nervous system infections given the additional possible harm of central nervous system immune reconstitution syndrome. Further study to evaluate continuation of ART regimens when presenting with cryptococcosis has benefit, with checking blood levels at presentation potentially being a helpful option. ClinicalTrials.gov Identifier: NCT01802385.

Pharmacokinetics and renal safety of tenofovir alafenamide with boosted protease inhibitors and ledipasvir/sofosbuvir

BACKGROUND

Ledipasvir/sofosbuvir increases tenofovir plasma exposures by up to 98% with tenofovir disoproxil fumarate (TDF), and exposures are highest with boosted PIs. There are currently no data on the combined use of the newer tenofovir prodrug, tenofovir alafenamide (TAF), boosted PIs and ledipasvir/sofosbuvir.

OBJECTIVES

To compare the plasma and intracellular pharmacokinetics and renal safety of TAF with ledipasvir/sofosbuvir when co-administered with boosted PIs.

METHODS

Persons with HIV between 18 and 70 years and on a boosted PI with TDF were eligible. The study was comprised of four phases: (1) TDF 300 mg with boosted PI; (2) TAF 25 mg with boosted PI; (3) TAF 25 mg with boosted PI and ledipasvir/sofosbuvir; and (4) TAF 25 mg with boosted PI. Pharmacokinetic sampling, urine biomarker collection [urine protein (UPCR), retinol binding protein (RBP) and β2 microglobulin (β2M) normalized to creatinine] and safety assessments occurred at the end of each phase. Plasma, PBMCs and dried blood spots were collected at each visit.

RESULTS

Ten participants were enrolled. Plasma tenofovir exposures were 76% lower and tenofovir-diphosphate (TFV-DP) concentrations in PBMCs increased 9.9-fold following the switch to TAF. Neither of these measures significantly increased with ledipasvir/sofosbuvir co-administration, nor did TAF plasma concentrations. No significant changes in estimated glomerular filtration rate or UPCR occurred, but RBP:creatinine and β2M:creatinine improved following the switch to TAF.

CONCLUSIONS

Ledipasvir/sofosbuvir did not significantly increase plasma tenofovir or intracellular TFV-DP in PBMCs with TAF. These findings provide reassurance that the combination of TAF, boosted PIs and ledipasvir/sofosbuvir is safe in HIV/HCV-coinfected populations.

Factors associated with tenofovir diphosphate concentrations in dried blood spots in persons living with HIV

OBJECTIVES

To determine factors associated with interindividual variability in tenofovir diphosphate (TFV-DP) concentrations in dried blood spots (DBSs) among persons living with HIV (PLWH).

METHODS

PLWH who were at least 18 years old and taking tenofovir disoproxil fumarate-containing ART were prospectively recruited and enrolled from a clinical cohort and followed longitudinally (up to three visits over 48 weeks). With log-transformed TFV-DP concentrations in DBSs as the outcome, mixed-model regression analyses were used to assess associations between self-reported 3 month ART adherence, race and other clinical covariates (gender, age, BMI, CD4+ T cell count, estimated glomerular filtration rate, haematocrit, duration on current ART and anchor drug class) on TFV-DP in DBSs.

RESULTS

Five hundred and twenty-seven participants (1150 person-visits) were analysed. Adjusting for race and other clinical covariates, every 10% increase in self-reported 3 month ART adherence was associated with an average TFV-DP concentration increase in DBSs of 28% (95% CI: 24%-32%; P < 0.0001). In the same model, female participants had 20% (95% CI: 3%-40%; P = 0.02) higher TFV-DP concentrations in DBSs, compared with male participants, and every 1 kg/m2 increase in BMI was associated with a decrease in TFV-DP concentration in DBSs by 2% (95% CI: -3% to -1%; P < 0.0001).

CONCLUSIONS

Individual patient characteristics were predictive of TFV-DP concentration in DBSs in PLWH receiving tenofovir disoproxil fumarate-based ART. Future research to incorporate these predictors into the interpretation of this ART adherence biomarker, and to establish whether these associations extend to PLWH taking tenofovir alafenamide-containing ART, is needed.