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OBJECTIVE: We sought to evaluate the utility of a point-of-care (POC) urine tenofovir (TFV) assay, developed to objectively assess adherence, to predict HIV drug resistance (HIVDR) in people failing first-line antiretroviral therapy (ART). DESIGN: We retrospectively analyzed TFV levels as a biomarker of adherence in urine specimens collected during a clinical trial that enrolled adults with virologic failure on first-line ART in Uganda and South Africa. METHODS: Urine specimens were analyzed from participants on TFV-containing regimens who had a viral load >1000 copies/ml and paired genotypic resistance test (GRT) results. We assessed recent ART TFV adherence with a qualitative POC lateral flow urine assay with a cut-off value of 1500 ng/ml. We then calculated performance characteristics of the POC urine TFV assay to predict HIVDR, defined as intermediate or high-level resistance to any component of the current ART regimen. RESULTS: Urine specimens with paired plasma GRT results were available from 283 participants. The most common ART regimen during study conduct was emtricitabine, tenofovir disoproxil fumarate, and efavirenz. The overall prevalence of HIVDR was 86% ( n = 243/283). Of those with TFV detected on the POC assay, 91% ( n  = 204/224) had HIVDR, vs. only 66% ( n  = 39/59) among those with no TFV detected ( P- value < 0.001). Positive and negative predictive values of the assay to predict HIVDR were 91% and 34%, respectively. CONCLUSIONS: In populations with a high prevalence of HIVDR, the POC urine TFV assay can provide a low-cost, rapid method to guide requirements for confirmatory resistance testing and inform the need for regimen change.

Introduction: Novel point‐of‐care assays which measure urine tenofovir (TFV) concentrations may have a role in improving adherence monitoring for people living with HIV (PLHIV) receiving antiretroviral therapy (ART). However, further studies of their diagnostic accuracy, and whether results are associated with viraemia and drug resistance, are needed to guide their use, particularly in the context of the global dolutegravir rollout. Methods: We conducted a cross‐sectional evaluation among PLHIV receiving first‐line ART containing tenofovir disoproxil fumarate at enrolment into a randomized trial in two South African public sector clinics. We calculated the diagnostic accuracy of the Abbott point‐of‐care immunoassay to detect urine TFV compared to liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). We evaluated the association between point‐of‐care urine TFV results and self‐reported adherence, viraemia ≥1000 copies/ml and HIV drug resistance, among people receiving either efavirenz or dolutegravir‐based ART. Results: Between August 2020 and March 2022, we enrolled 124 participants. The median age was 39 (IQR 34–45) years, 55% were women, 74 (59.7%) were receiving efavirenz and 50 (40.3%) dolutegravir. The sensitivity and specificity of the immunoassay to detect urine TFV ≥1500 ng/ml compared to LC‐MS/MS were 96.1% (95% CI 90.0−98.8) and 95.2% (75.3−100.0), respectively. Urine TFV results were associated with short (p<0.001) and medium‐term (p = 0.036) self‐reported adherence. Overall, 44/124 (35.5%) had viraemia, which was associated with undetectable TFV in those receiving efavirenz (OR 6.01, 1.27−39.0, p = 0.014) and dolutegravir (OR 25.7, 4.20−294.8, p<0.001). However, in those with viraemia while receiving efavirenz, 8/27 (29.6%) had undetectable urine TFV, compared to 11/17 (64.7%) of those receiving dolutegravir. Drug resistance was detected in 23/27 (85.2%) of those receiving efavirenz and only 1/16 (6.3%) of those receiving dolutegravir. There was no association between urine TFV results and drug resistance. Conclusions: Among PLHIV receiving ART, a rapid urine TFV immunoassay can be used to accurately monitor urine TFV levels compared to the gold standard of LC‐MS/MS. Undetectable point‐of‐care urine TFV results were associated with viraemia, particularly among people receiving dolutegravir. Trial registration: Pan‐African Clinical Trials Registry: PACTR202001785886049. [ABSTRACT FROM AUTHOR]

HIV cerebrospinal fluid (CSF) escape, where HIV is suppressed in blood but detectable in CSF, occurs when HIV persists in the CNS despite antiretroviral therapy (ART). To determine the virus producing cell type and whether lowered CSF ART levels are responsible for CSF escape, we collected blood and CSF from 156 neurosymptomatic participants from Durban, South Africa. We observed that 28% of participants with an undetectable HIV blood viral load showed CSF escape. We detected host cell surface markers on the HIV envelope to determine the cellular source of HIV in participants on the first line regimen of efavirenz, emtricitabine, and tenofovir. We confirmed CD26 as a marker which could differentiate between T cells and macrophages and microglia, and quantified CD26 levels on the virion surface, comparing the result to virus from in vitro infected T cells or macrophages. The measured CD26 level was consistent with the presence of T cell produced virus. We found no significant differences in ART concentrations between CSF escape and fully suppressed individuals in CSF or blood, and did not observe a clear association with drug resistance mutations in CSF virus which would allow HIV to replicate. Hence, CSF HIV in the face of ART may at least partly originate in CD4+ T cell populations. Author summary: The brain may be a site where HIV persists despite antiretroviral therapy (ART). Persistence can manifest as cerebrospinal fluid (CSF) escape, where HIV is detectable in the CSF but not the blood in some individuals. The reasons for CSF escape are incompletely understood. Evidence from individuals mostly on second line protease inhibitor-based ART indicates that detectable HIV in this compartment may have acquired drug resistance. In this work we investigated HIV in blood and CSF of 156 participants from Durban, South Africa. We observed a very high prevalence of CSF escape of 28%. We aimed to find the cell type responsible for producing HIV in CSF escape and whether replication occurred because of lower CSF drug levels or because the virus has developed resistance to therapy. We found that at least some of the CSF HIV was produced by T cells, and that drug resistance was not always present. This suggests that at least part of the CSF HIV reservoir may be generated by either an infection mode not requiring drug resistance for viral replication, or by latently infected CD4+ T cells trafficking to and releasing HIV in the CSF without extensive viral replication taking place. [ABSTRACT FROM AUTHOR]

Problem: Injectable hormonal contraceptives (IHC) have been associated with altered mucosal and systemic milieu which might increase HIV risk, but most studies have focused on DMPA and not NET‐EN, despite the growing popularity and lower HIV risk associated with the latter in observational studies. Method of study: We used high‐performance liquid chromatography in combination with tandem triple quadrupole mass spectrometry (HPLC‐LC‐MS/MS) to measure steroid hormones in plasma samples of CAPRISA004 study participants. Concentrations of 48 cytokines were measured in the cervicovaginal lavage (CVL) and plasma, and their expression was compared between participants with detectable NET‐EN (n = 201) versus non‐detectable IHC (n = 90). Each log10 cytokine concentration was tested as an outcome in linear‐mixed models, with NET‐EN detection as the main explanatory variable. Multivariable models were adjusted for potential confounders. Results: In bivariate analysis, detectable NET‐EN was associated with reduced cervicovaginal M‐CSF (P = 0.008), GM‐CSF (P = 0.025) and G‐CSF (P = 0.039), and elevated levels MIF (P = 0.008), IL‐18 (P = 0.011), RANTES (P = 0.005) and IL‐1Rα (P < 0.001). Lower G‐CSF (P = 0.011) and elevated IL‐1Rα (P = 0.008) remained significant in adjusted models. Multivariable analyses of plasma samples obtained from NET‐EN‐detectable women showed a significant increase in IP‐10 (P = 0.026) and reductions in TNF‐β (P = 0.037), RANTES (P = 0.009), and M‐CSF (P < 0.001). While similar growth factor reduction in CVL was noted for both DMPA and NET‐EN, similar trends were not observed for endogenous progesterone. Conclusions: Detectable NET‐EN was associated with reduced growth factors in the plasma and genital tract; particularly G‐CSF and M‐CSF. Our results suggest that while NET‐EN is not inflammatory, it may have important immunological effects. [ABSTRACT FROM AUTHOR]

Objectives: We compared the pharmacokinetics of moxifloxacin during rifampicin co-treatment or when dosed alone in African patients with drug-susceptible recurrent TB.Methods: Patients in the intervention arm of the Improving Retreatment Success (IMPRESS) randomized controlled TB trial received 400 mg of moxifloxacin, with rifampicin, isoniazid and pyrazinamide in the treatment regimen. Moxifloxacin concentrations were measured in plasma during rifampicin-based TB treatment and again 4 weeks after treatment completion, when given alone as a single dose. Moxifloxacin concentration-time data were analysed using non-linear mixed-effects models.Results: We included 58 patients; 42 (72.4%) were HIV co-infected and 40 (95%) of these were on efavirenz-based ART. Moxifloxacin pharmacokinetics was best described using a two-compartment disposition model with first-order lagged absorption and elimination using a semi-mechanistic model describing hepatic extraction. Oral clearance (CL/F) of moxifloxacin during rifampicin-based TB treatment was 24.3 L/h for a typical patient (fat-free mass of 47 kg), resulting in an AUC of 16.5 mg·h/L. This exposure was 7.8% lower than the AUC following the single dose of moxifloxacin given alone after TB treatment completion. In HIV-co-infected patients taking efavirenz-based ART, CL/F of moxifloxacin was increased by 42.4%, resulting in a further 30% reduction in moxifloxacin AUC.Conclusions: Moxifloxacin clearance was high and plasma concentrations low in our patients overall. Moxifloxacin AUC was further decreased by co-administration of efavirenz-based ART and, to a lesser extent, rifampicin. The clinical relevance of the low moxifloxacin concentrations for TB treatment outcomes and the need for moxifloxacin dose adjustment in the presence of rifampicin and efavirenz co-treatment need further investigation. [ABSTRACT FROM AUTHOR]

Prolonged virologic failure on 2nd-line protease inhibitor (PI)-based antiretroviral therapy (ART) without emergence of major protease mutations is well recognized and provides an opportunity to study within-host evolution in long-term viremic individuals. Using next-generation sequencing and in silico haplotype reconstruction, we analyzed whole-genome sequences from longitudinal plasma samples of eight chronically infected HIV-1-positive individuals failing 2nd-line regimens from the French National Agency for AIDS and Viral Hepatitis Research (ANRS) 12249 Treatment as Prevention (TasP) trial. On nonsuppressive ART, there were large fluctuations in synonymous and nonsynonymous variant frequencies despite stable viremia. Reconstructed haplotypes provided evidence for selective sweeps during periods of partial adherence, and viral haplotype competition, during periods of low drug exposure. Drug resistance mutations in reverse transcriptase (RT) were used as markers of viral haplotypes in the reservoir, and their distribution over time indicated recombination. We independently observed linkage disequilibrium decay, indicative of recombination. These data highlight dramatic changes in virus population structure that occur during stable viremia under nonsuppressive ART. IMPORTANCE HIV-1 infections are most commonly initiated with a single founder virus and are characterized by extensive inter- and intraparticipant genetic diversity. However, existing literature on HIV-1 intrahost population dynamics is largely limited to untreated infections, predominantly in subtype B-infected individuals. The manuscript characterizes viral population dynamics in long-term viremic treatment-experienced individuals, which has not been previously characterized. These data are particularly relevant for understanding HIV dynamics but can also be applied to other RNA viruses. With this unique data set we propose that the virus is highly unstable, and we have found compelling evidence of HIV-1 within-host viral diversification, recombination, and haplotype competition during nonsuppressive ART.

HIV infection in the human gastrointestinal (GI) tract is thought to be central to HIV progression, but knowledge of this interaction is primarily limited to cohorts within Westernized countries. Here, we present a large cohort recruited from high HIV endemic areas in South Africa and found that people living with HIV (PLWH) presented at a younger age for investigation in the GI clinic. We identified severe CD4+ T cell depletion in the GI tract, which was greater in the small intestine than in the large intestine and not correlated with years on antiretroviral treatment (ART) or plasma viremia. HIV-p24 staining showed persistent viral expression, particularly in the colon, despite full suppression of plasma viremia. Quantification of mucosal antiretroviral (ARV) drugs revealed no differences in drug penetration between the duodenum and colon. Plasma markers of gut barrier breakdown and immune activation were elevated irrespective of HIV, but peripheral T cell activation was inversely correlated with loss of gut CD4+ T cells in PLWH alone. T cell activation is a strong predictor of HIV progression and independent of plasma viral load, implying that the irreversible loss of GI CD4+ T cells is a key event in the HIV pathogenesis of PLWH in South Africa, yet the underlying mechanisms remain unknown.

Aim: We report the prevalence and effect of genetic variability on pharmacokinetic parameters of isoniazid and rifampicin., Materials & Methods: Genotypes for SLCO1B1, NAT2, PXR, ABCB1 and UGT1A genes were determined using a TaqMan ® Genotyping OpenArray™. Nonlinear mixed-effects models were used to describe drug pharmacokinetics., Results: Among 172 patients, 18, 43 and 34% were classified as rapid, intermediate and slow NAT2 acetylators, respectively. Of the 58 patients contributing drug concentrations, rapid and intermediate acetylators had 2.3- and 1.6-times faster isoniazid clearance than slow acetylators. No association was observed between rifampicin pharmacokinetics and SLCO1B1, ABCB1, UGT1A or PXR genotypes., Conclusion: Clinical relevance of the effects of genetic variation on isoniazid concentrations and low first-line tuberculosis drug exposures observed require further investigation.