Efavirenz plasma levels can predict treatment failure and central nervous system side effects in HIV-1-infected patients

Determining Targets for Antiretroviral Drug Concentrations: A Causal Framework Illustrated With Pediatric Efavirenz Data From the CHAPAS-3 Trial

BACKGROUND

Determining a therapeutic window for maintaining antiretroviral drug concentrations within an appropriate range is required for identifying effective dosing regimens. The limits of this window are typically calculated using predictive models. We propose that target concentrations should instead be calculated based on counterfactual probabilities of relevant outcomes and describe a counterfactual framework for this.

METHODS

The proposed framework is applied in an analysis including longitudinal observational data from 125 HIV-positive children treated with efavirenz-based regimens within the CHAPAS-3 trial, which enrolled children < 13 years in Zambia/Uganda. A directed acyclic graph was developed to visualize the mechanisms affecting antiretroviral concentrations. Causal concentration-response curves, adjusted for measured time-varying confounding of weight and adherence, are calculated using g-computation.

RESULTS

The estimated curves show that higher concentrations during follow-up, 12/24 h after dose, lead to lower probabilities of viral failure (> 100 c/mL) at 96 weeks of follow-up. Estimated counterfactual failure probabilities under the current target range of 1-4 mg/L range from 24% to about 2%. The curves are almost identical for slow, intermediate and extensive metabolizers and show that a mid-dose concentration level of ≥ 3.5 mg/L would be required to achieve a failure probability of < 5%.

CONCLUSIONS

Our analyses demonstrate that a causal approach may lead to different minimum concentration limits than analyses that are based on purely predictive models. Moreover, the approach highlights that indirect causes of failure, such as patients' metabolizing status, may predict patients' failure risk, but do not alter the threshold at which antiviral activity of efavirenz is severely reduced.

Challenges and Opportunities for Consideration of Efavirenz Drug Repurposing for Alzheimer's Disease Therapeutics

Therapeutic research and development for Alzheimer's disease (AD) has been an area of intense research to alleviate memory loss and neurodegeneration. There is growing interest in drug repositioning and repurposing strategies for FDA-approved medications as potential candidates that may further advance AD therapeutics. The FDA drug efavirenz has been investigated as a candidate drug for repurposing as an AD medication. The proposed mechanism of action of efavirenz (at low doses) is the activation of the neuron-specific enzyme CYP46A1 that converts excess brain cholesterol into 24-hydroxycholesterol (24-HC) that is exported to the periphery. Efavirenz at a low dose was found to improve memory deficit in the 5XFAD model of AD that was accompanied by elevated 24-HC and reduction in Aβ; furthermore, efavirenz reduced pTau and excess cholesterol levels in human iPSC-derived Alzheimer's neurons. The low dose of efavirenz used in the AD mouse model to increase 24-HC contrasts with the use of more than 100-fold higher doses of efavirenz for clinical treatment of human immunodeficiency virus (HIV) through inhibition of reverse transcriptase. Low doses of efavirenz may avoid neurotoxic adverse effects that occur at high efavirenz doses used for HIV treatment. This review evaluates the drug properties of efavirenz with respect to its preclinical data on regulating memory deficit, pharmacokinetics, pharmacodynamics, metabolites, and genetic variabilities in drug metabolism as well as its potential adverse effects. These analyses discuss the challenges and questions that should be addressed in future studies to consider the opportunity for low dose efavirenz as a candidate for AD drug development.

Quantification of Efavirenz Hydroxymetabolites in Human Plasma Using LC-HRMS/MS

BACKGROUND

Efavirenz (EFV) is a drug used to treat HIV. Low plasma concentrations of EFV result in suboptimal viral suppression, whereas high concentrations can cause adverse neuropsychiatric side reactions. Some studies have identified a correlation between the plasma concentrations of EFV metabolites and neurotoxicity. To our knowledge, no studies have investigated the metabolism of EFV in young children and its effect on treatment outcomes. Therefore, the aim of this study was to develop and validate a method for quantifying EFV and its metabolites in human plasma derived from children.

METHODS

Sample preparation was performed using protein precipitation of 100 µL plasma. Thereafter, an aliquot of the supernatant was used to quantify EFV, 7-hydroxyefavirenz (7-OH-EFV), 8-hydroxyefavirenz (8-OH-EFV), and a newly discovered metabolite ("EFAdeg") associated with 8-OH-EFV. A second aliquot of the supernatant was hydrolyzed using β-glucuronidase/arylsulfatase and used with the first aliquot to quantify phase II metabolites. The analyses were performed using a Dionex Ultimate 3000RS LC-system coupled with a Q Exactive Orbitrap mass spectrometer.

RESULTS

The method has a measuring range of 100-50,000 ng/mL (EFV, 8-OH-EFV), 125-25,000 ng/mL (7-OH-EFV), and 200-10,000 ng/mL ("EFAdeg"). All criteria of the European Medicines Agency guidelines regarding precision, accuracy, and selectivity were met. Of note, carryover must be considered for 8-OH-EFV. Overall, the validated method was successfully applied to plasma samples obtained from children and confirmed the presence of the newly discovered metabolite, "EFAdeg."

CONCLUSIONS

An LC-HRMS/MS method for the quantification of EFV and its phase I and II metabolites was developed and validated. This method is suitable for analyzing plasma samples from children. Furthermore, studies using this method identified an additional metabolite that may influence the concentration of 8-OH-EFV in patient samples.

Antiretroviral Drugs Impact Autophagy: Opportunities for Drug Repurposing

Autophagy is an evolutionarily conserved process in which intracellular macromolecules are degraded in a lysosomal-dependent manner. It is central to cellular energy homeostasis and to quality control of intracellular components. A decline in autophagic activity is associated with aging, and contributes to the development of various age-associated pathologies, including cancer. There is an ongoing need to develop chemotherapeutic agents to improve morbidity and mortality for those diagnosed with cancer, as well as to decrease the cost of cancer care. Autophagic programs are altered in cancer cells to support survival in genetically and metabolically unstable environments, making autophagy an attractive target for new chemotherapy. Antiretroviral drugs, which have dramatically increased the life- and health spans of people with human immunodeficiency virus (HIV) (PWH), have offered promise in the treatment of cancer. One mechanism underlying the antineoplastic effects of antiretroviral drugs is the alteration of cancer cell autophagy that can potentiate cell death. Antiretroviral drugs could be repurposed into the cancer chemotherapy arsenal. A more complete understanding of the impact of antiretroviral drugs on autophagy is essential for effective repurposing. This review summarizes our knowledge of the effects of antiretroviral drugs on autophagy as potential adjunctive chemotherapeutic agents, and highlights gaps to be addressed to reposition antiretroviral drugs into the antineoplastic arsenal successfully.

The Association of Intraocular Efavirenz Concentrations and HIV-1 Viral Load Among Persons With HIV

OBJECTIVE

Efavirenz (EFV) is commonly used in combination antiretroviral therapy. However, in our previous study, many persons living with HIV exhibited ocular complications despite undergoing effective combination antiretroviral therapy. Here, we aimed to determine the intraocular EFV concentrations in the vitreous and analyze the factors affecting viral load in the vitreous in patients with HIV-associated retinopathies.

DESIGN

Observational, retrospective study.

METHODS

Fourteen patients receiving EFV in combination with an antiretroviral therapy who underwent pars plana vitrectomy were enrolled between January 2019 and August 2022. The patients were divided into 2 groups based on presence or absence of retinal detachment (RD). Patient characteristics and HIV-1 RNA levels in plasma and vitreous were recorded during pars plana vitrectomy. Paired blood plasma and vitreous samples were obtained for EFV concentration analysis using ultra-high-performance liquid chromatography/tandem mass spectrometry.

RESULTS

The median age of the enrolled patients was 48 years (interquartile range, 32.25-53.25), including 12 men and 2 women. Median vitreous and plasma EFV concentrations were 141.5 (interquartile range, 69.63-323.75) and 2620 ng/mL (1680-4207.5), respectively. Median ratio of vitreous/plasma EFV concentrations in the paired samples among all participants was 0.053 (0.018-0.118). Median vitreous/plasma EFV concentrations significantly differed between the non-RD and RD groups (0.04 vs 0.12, P = 0.042).

CONCLUSIONS

The vitreous EFV concentrations were insufficient to inhibit viral replication in intraocular tissues, which may be because of poor penetration of the blood-retinal barrier. High vitreous EFV concentrations were associated with RD, indicating a correlation between the EFV concentration and the severity of blood-retinal barrier disruption. It implied that EFV was not a suitable antiviral drug to inhibit HIV-1 replication in ocular tissues.

Health-Related Quality of Life in People with Advanced HIV Disease, from 1996 to 2021: Systematic Review and Meta-analysis

The purpose of the study was to assess the effects of advanced HIV disease (AHD) on health-related quality of life (HRQoL) in PLHIV, the changes in HRQoL outcomes over the last 25 years, and the differences between countries according to level of economic development. We conducted a systematic review and meta-analysis. The search was conducted in PubMed and Web of Science using the terms: "health-related quality of life", "HQRoL", "HIV", "AIDS", "advanced HIV disease" and "low CD4 cells". Studies inclusion criteria were: adult population; initiated after 1996 and published before July 2021; clinical trials, cross-sectional, cohort, and case-control studies; studies analyzing the relationship between AHD and HRQoL; English or Spanish language. Standardized mean differences (d+) were calculated to estimate the effect size for the meta-analyses. Summary statistics were calculated using a random-effects model, and analyses of effect moderators, using mixed-effects models. The meta-analysis included 38 studies. The results indicated that HRQoL is worse in patients with AHD compared to those without. The main HRQoL domains affected were overall health perception and concern and physical and functional health and symptoms. We found a moderate impact for age and gender on some HRQoL domains. There were no differences in relation to socioeconomic inequities, country of residence, or time period analyzed. In conclusion, advanced HIV disease has a negative impact on health and well-being in PLHIV. Our results show that despite all the advances in antiretroviral treatments over the last 25 years, AHD persists as a source of extreme vulnerability, regardless of where PLHIV live.

A validated method for simultaneous quantification of four antiretrovirals in dried blood spot and plasma using LC-MS/MS: Application to efavirenz therapeutic drug monitoring in pregnant patients

INTRODUCTION

The specific physiological background induced by pregnancy leads to significant changes in maternal pharmacokinetics, suggesting potential variability in plasma concentrations of antiretrovirals. Pregnant HIV patients exposed to subtherapeutic doses, particularly in the last trimester of the pregnancy, have higher chances to transmit the infection to their children. Therefore, the therapeutic drug monitoring of antiretrovirals in HIV pregnant patients would be of great value.

OBJECTIVES

This study aimed to develop and validate a sensitive liquid chromatograph tandem mass spectrometry (LC-MS/MS) method for simultaneous quantification of efavirenz, raltegravir, atazanavir, and ritonavir in dried blood spots (DBS) and plasma.

DESIGN AND METHODS

The analytes were extracted from the DBS punch and plasma with a mixture of methanol:zinc sulfate 200 mM (50:50, v/v) and 100 % methanol, respectively. For the chromatographic separation a Shim-pack® C18, 4.6 mm × 150 mm, 5 μm column was used. Detection was performed in a 3200-QTRAP® mass spectrometer, with a run time of 6 min.

RESULTS

The assay was linear in the range of 15-1,000 ng/mL for raltegravir, 50-10,000 ng/mL for both atazanavir and ritonavir, 50-5,000 ng/mL for efavirenz. Precision and accuracy at these concentrations were less than 15 % for all analytes. Raltegravir, atazanavir, and ritonavir were stable for seven days at 23 °C and 40 °C, whereas efavirenz was stable for twenty-four hours at the same conditions.

CONCLUSIONS

The method was successfully applied to quantify efavirenz in DBS samples obtained from HIV-1 infected pregnant volunteers under antiretroviral therapy. The concentrations of efavirenz in DBS and plasma were comparable according to Passing-Bablok regression and Bland-Altman analysis.

Influence of efavirenz and 8-hydroxy-efavirenz plasma levels on cognition and central nervous system side effects

OBJECTIVES

To investigate whether efavirenz (EFV) or 8-hydroxy-EFV (8-OH-EFV) plasma levels are associated with neurocognitive impairment and central nervous system (CNS) side effects.

METHODS

We conducted a cross-sectional analysis to explore the potential links between EFV/8-OH-EFV levels and cognitive performance or CNS-related side effects in patients screened within a randomized trial involving a switch from EFV to rilpivirine. The Mann-Whitney test was employed to compare drug levels in patients with or without cognitive impairment, depression, anxiety, sleep disorder or CNS symptoms. Additionally, Spearman's test was used to assess correlations between drug levels and test scores.

RESULTS

Among 104 patients, neither EFV nor 8-OH-EFV levels were linked to cognitive impairment, although trends towards higher EFV levels were observed in those with impaired executive function (p = 0.055) and language performances (p = 0.021). On the other hand, elevated 8-OH-EFV levels, but not EFV levels, were associated with more CNS side effects (222 vs. 151 ng/mL, p = 0.027), depressive symptoms (247 vs. 164 ng/mL, p = 0.067) and sleep impairment (247 vs. 164 ng/mL, p = 0.078). Consistently, a trend towards a correlation between EFV levels and lower z-scores in executive function and motor function was observed, while 8-OH-EFV levels, but not EFV levels, were directly correlated with symptom scores.

CONCLUSIONS

Higher levels of 8-OH-EFV were associated with CNS side effects, while EFV levels were only marginally associated with cognitive performance, thus suggesting that EFV and its metabolite may act differently in determining detrimental neurological effects.

Dual strategy to improve the oral bioavailability of efavirenz employing nanomicelles and curcumin as a bio-enhancer

The present investigation was focused on the development of Soluplus®-based nanomicelles (NMs) (10 % w/v) loaded with Efavirenz (EFV) (5 mg/mL) and Curcumin (natural bio-enhancer) (CUR) (5, 10 and 15 mg/mL) to improve the oral bioavalability of EFV. Micellar formulations were obtained employing an acetone-diffusion technique. Apparent aqueous solubility was increased up to ∼1250-fold and 25,000-fold for EFV and CUR, respectively. Drug-loaded nanoformulations showed an excellent colloidal stability with unimodal size distribution and PDI values < 0.30. In vitro drug release was 41.5 % (EFV) and 2.6 % (CUR) from EFV-CUR-NMs over 6 h in simulated gastrointestinal fluids. EFV-CUR-loaded NMs resulted as safe nanoformulations according to the in vitro cytocompatibility assays in Caco-2 cells. Furthermore, CUR bio-enhancer activity was demonstrated for those nanoformulations. A CUR concentration of 15 mg/mL produced a significant (p < 0.05) increment (2.64-fold) of relative EFV oral bioavailability. Finally, the active role of the lymphatic system in the absorption process of EFV, after its oral administration was assessed in a comparative pharmacokinetic study in presence and absence of cycloheximide, a lymphatic transport inhibitor. Overall our EFV-CUR-NMs denoted their potential as a novel nanotechnological platform, representing a step towards an optimized "nano-sized" therapy for AIDS patients.

Proposal of pharmacophore model for HIV reverse transcriptase inhibitors: Combined mutational effect analysis, molecular dynamics, molecular docking and pharmacophore modeling study

OBJECTIVES

Antiretroviral therapy (ART) efficacy is jeopardized by the emergence of drug resistance mutations in HIV, compromising treatment effectiveness. This study aims to propose novel analogs of Effavirenz (EFV) as potential direct inhibitors of HIV reverse transcriptase, employing computer-aided drug design methodologies.

METHODS

Three key approaches were applied: a mutational profile study, molecular dynamics simulations, and pharmacophore development. The impact of mutations on the stability, flexibility, function, and affinity of target proteins, especially those associated with NRTI, was assessed. Molecular dynamics analysis identified G190E as a mutation significantly altering protein properties, potentially leading to therapeutic failure. Comparative analysis revealed that among six first-line antiretroviral drugs, EFV exhibited notably low affinity with viral reverse transcriptase, further reduced by the G190E mutation. Subsequently, a search for EFV-similar inhibitors yielded 12 promising molecules based on their affinity, forming the basis for generating a pharmacophore model.

RESULTS

Mutational analysis pinpointed G190E as a crucial mutation impacting protein properties, potentially undermining therapeutic efficacy. EFV demonstrated diminished affinity with viral reverse transcriptase, exacerbated by the G190E mutation. The search for EFV analogs identified 12 high-affinity molecules, culminating in a pharmacophore model elucidating key structural features crucial for potent inhibition.

CONCLUSION

This study underscores the significance of EFV analogs as potential inhibitors of HIV reverse transcriptase. The findings highlight the impact of mutations on drug efficacy, particularly the detrimental effect of G190E. The generated pharmacophore model serves as a pivotal reference for future drug development efforts targeting HIV, providing essential structural insights for the design of potent inhibitors based on EFV analogs identified in vitro.

Genetic and non-genetic factors influencing efavirenz population pharmacokinetics among human immunodeficiency virus-1-infected children in Ethiopia

Despite the potential for efavirenz (EFV) to be an effective alternative antiretroviral agent, its sources of wide inter- and intra-individual pharmacokinetic (PK) variability are not well-characterized in children. We investigated the effects of genetic and non-genetic factors, including demographic, treatment duration, baseline clinical, and biochemical characteristics, on the PKs of EFV through population-PK modeling. Antiretroviral therapy (ART) naïve HIV infected children, 3-16 years (n = 100), were enrolled in Ethiopia and received EFV-based combination ART. EFV concentrations after the first dose and at steady-state collected over a span of 1 year were modeled using population-based methods. A one-compartment model with first-order absorption kinetics described the observed EFV data adequately. The CYP2B6*6 and ABCB1c.4036A>G genotypes were identified as major factors influencing EFV clearance. The typical estimates of oral clearance, volume of distribution, and absorption rate constant for typical 22 kg children with CYP2B6 *1/*1 and ABCB1c.4036G/G genotypes were 4.3 L/h, 124 L, and 0.776/h, respectively. Clearance was reduced by 28% and 72% in CYP2B6*1/*6 and CYP2B6*6/*6 genotypes, respectively. Compared to week 1, clearance was higher from weeks 8 and 12 in CYP2B6*1/*6 and CYP2B6*1/*1 genotypes, respectively. Simulations indicated that EFV 12-h concentrations were comparable across weight bands, but more than 80% of subjects with CYP2B6*6/*6 had EFV concentrations greater than 4 μg/mL. EFV PK variability among children is partly explained by body weight, treatment duration, CYP2B6*6, and ABCB1 rs3842 genotypes. Therefore, in addition to body weight, pediatric dosing of EFV should consider pharmacogenetic variability, duration of therapy, and individual treatment outcomes.

Pharmacokinetics of dose-adjusted levonorgestrel emergency contraception combined with efavirenz-based antiretroviral therapy or rifampicin-containing tuberculosis regimens

OBJECTIVES

To determine if double-dose levonorgestrel emergency contraception (EC) in combination with efavirenz or rifampicin, 2 drugs known to decrease levonorgestrel exposure, resulted in similar pharmacokinetics compared to standard-dose levonorgestrel EC without drug-drug interactions.

STUDY DESIGN

We conducted a phase 2, open-label, multicenter, partially randomized, 4 parallel group trial in pre-menopausal females ≥16 years old without an indication for EC and not on hormonal contraception. Participants on dolutegravir-based antiretroviral therapy (ART) received levonorgestrel 1.5 mg (control group); those on rifampicin-containing tuberculosis therapy received levonorgestrel 3 mg; those on efavirenz-based ART were randomized 1:2 to levonorgestrel 1.5 mg or 3 mg. Plasma was collected through 48 hours post-dose to assess levonorgestrel pharmacokinetics. Area under the concentration-time curve (AUC) over 8 hours was the primary outcome. Levonorgestrel pharmacokinetic parameters were compared between groups using geometric mean ratios (GMR) with 90% confidence intervals.

RESULTS

The median (Q1, Q3) age for all participants (n = 118) was 34 (27, 41) years and BMI was 23.2 (20, 26.3) kg/m2. Participants receiving levonorgestrel 1.5mg plus efavirenz (n = 17) had 50% lower AUC0-8h compared to the control group (n = 32) [0.50 (0.40, 0.62)]. Participants receiving levonorgestrel 3 mg had a similar AUC0-8h when receiving either efavirenz (n = 35) [0.99 (0.81, 1.20)] or rifampicin (n = 34) [1.16 (0.99, 1.36)] compared to control. Levonorgestrel 3 mg resulted in similar or higher maximum concentration with either efavirenz [1.17 (0.96, 1.41)] or rifampicin [1.27 (1.09, 1.49)] compared to the control group.

CONCLUSIONS

Doubling the dose of levonorgestrel EC successfully increased levonorgestrel exposure over the first 8 hours in participants receiving either efavirenz-based ART or rifampicin-containing tuberculosis therapy.

IMPLICATIONS

Adjusting levonorgestrel emergency contraception from 1.5 mg to 3 mg improves levonorgestrel pharmacokinetic exposure in participants receiving either efavirenz-based antiretroviral regimens or rifampicin-containing tuberculosis therapy. These data support guideline recommendations to double the dose of levonorgestrel emergency contraception in persons on medications that decrease levonorgestrel exposure by inducing levonorgestrel metabolism.

Relating CYP2B6 genotype and efavirenz resistance among post-partum women living with HIV with high viremia in Uganda: a nested cross-sectional study

BACKGROUND

We investigated the association between CYP2B6 polymorphisms and efavirenz drug resistance among women living with HIV who started on antiretroviral therapy during pregnancy and with high viremia during post-partum.

METHODS

This was a cross-sectional study of women with viral loads greater than 1000 copies/ml who were at least 6 weeks postpartum. Sanger sequencing was used to detect resistant mutations, as well as host genotyping, and efavirenz resistance was compared among the metabolizer genotypes.

RESULTS

Over the course of one year (July 2017-July 2018), 322 women were screened, with 110 (34.2%) having viral loads of 1000 copies/ml and 62 having whole blood available for genotyping. Fifty-nine of these women had both viral resistance and human host genotypic results. Efavirenz resistance according to metabolizer genotype was; 47% in slow, 34% in extensive and 28% in intermediate metabolizers, but the difference was not statistically significant due to the small sample size.

CONCLUSIONS

There was no statistically significant difference in EFV resistance between EFV metabolizer genotypes in women who started antiretroviral therapy during pregnancy and had high viremia in the postpartum period. However, a numerical trend was discovered, which calls for confirmation in a large, well-designed, statistically powered study.

Effect of double-dose levonorgestrel subdermal implant in women taking efavirenz-based antiretroviral therapy: The DoubLNG pharmacokinetic study

OBJECTIVE

We evaluated the pharmacokinetics of double-dose levonorgestrel (LNG) implants to overcome the drug-drug interaction with efavirenz-based antiretroviral therapy (ART).

STUDY DESIGN

We conducted a nonrandomized, open-label, parallel-group, longitudinal pharmacokinetic study among Ugandan women ages 18-45 years. Participants with HIV on ART containing efavirenz 600 mg received 300 mg of LNG implants (Jadelle®, Bayer, New Zealand): 300LNG+ART group. We compared our outcomes with women without HIV using standard dose, 150 mg of LNG implants: 150LNG group. The implant was placed on day zero in both groups, and we quantified plasma LNG concentrations over 48 weeks post implant insertion. LNG pharmacokinetic parameters were estimated using noncompartmental techniques. Our primary outcome was the geometric mean ratio with 90% confidence intervals of LNG area under the concentration-time curve over 24 weeks (AUC_0-24w) between groups. Demographic data were described as median (interquartile range). A secondary outcome compared between-group percent of LNG concentrations ≥300 pg/mL, a minimum threshold selected a priori based on observed pregnancies in Ugandan women on standard-dose LNG implants plus efavirenz.

RESULTS

We enrolled 27 women in the 300LNG+ART group (34 [28.0 to 40.5] years and 61.0 [49.8-66.0] kg) and 19 women in the 150LNG group (33 [30.0 to 34.5] years and 64.9 [59.0 to 74.5] kg). LNG AUC_0-24w was 34% lower for 300LNG+ART versus 150LNG (geometric mean 9998 vs. 15,231 pg*week/mL, respectively [geometric mean ratio 0.66 (90% confidence intervals, 0.54 to 0.80)]). The percentage of participants with LNG concentrations ≥300 pg/mL was not statistically different between groups at week 24 (300LNG+ART: 74.1%; 150LNG: 89.5%; p = 0.27).

CONCLUSION

Double-dose LNG implant did not completely overcome the drug-drug interaction with efavirenz.

IMPLICATION

In women using ART containing efavirenz, placing two implant systems (300 mg) did not normalize LNG pharmacokinetics compared with the standard-dose implant (150 mg), and some women had evidence of ovulatory activity. Alternative ART without drug-drug interactions, such as dolutegravir, is recommended with contraceptive implants.

Decreased Dolutegravir and Efavirenz Concentrations With Preserved Virological Suppression in Patients With Tuberculosis and Human Immunodeficiency Virus Receiving High-Dose Rifampicin

BACKGROUND

Higher doses of rifampicin may improve treatment outcomes and reduce the duration of tuberculosis (TB) therapy. However, drug-drug interactions with antiretroviral therapy (ART) and safety in people with human immunodeficiency virus (HIV) have not been evaluated.

METHODS

This was a randomized, open-label trial where newly diagnosed TB patients were randomized to higher (35 mg/kg) or standard (10 mg/kg) daily-dose rifampicin. ART treatment-naive patients were randomized to dolutegravir- or efavirenz-based ART. At week 6, trough dolutegravir or mid-dose efavirenz plasma concentrations were assayed. HIV viral load was measured at week 24.

RESULTS

Among 128 patients randomized, the median CD4 count was 191 cells/mm3. The geometric mean ratio (GMR) for trough dolutegravir concentrations on higher- vs standard-dose rifampicin was 0.57 (95% confidence interval [CI], .34-.97; P = .039) and the GMR for mid-dose efavirenz was 0.63 (95% CI, .38-1.07; P = .083). There was no significant difference in attainment of targets for dolutegravir trough or efavirenz mid-dose concentrations between rifampicin doses. The incidence of HIV treatment failure at week 24 was similar between rifampicin doses (14.9% vs 14.0%, P = .901), as was the incidence of drug-related grade 3-4 adverse events (9.8% vs 6%). At week 8, fewer patients remained sputum culture positive on higher-dose rifampicin (18.6% vs 37.0%, P = .063).

CONCLUSIONS

Compared with standard-dose rifampicin, high-dose rifampicin reduced dolutegravir and efavirenz exposures, but HIV suppression was similar across treatment arms. Higher-dose rifampicin was well tolerated among people with HIV and associated with a trend toward faster sputum culture conversion.

CLINICAL TRIALS REGISTRATION

NCT03982277.

Rifapentine With and Without Moxifloxacin for Pulmonary Tuberculosis in People With Human Immunodeficiency Virus (S31/A5349)

BACKGROUND

Tuberculosis (TB) Trials Consortium Study 31/AIDS Clinical Trials Group A5349, an international randomized open-label phase 3 noninferiority trial showed that a 4-month daily regimen substituting rifapentine for rifampin and moxifloxacin for ethambutol had noninferior efficacy and was safe for the treatment of drug-susceptible pulmonary TB (DS-PTB) compared with the standard 6-month regimen. We explored results among the prespecified subgroup of people with human immunodeficiency virus (HIV) (PWH).

METHODS

PWH and CD4+ counts ≥100 cells/μL were eligible if they were receiving or about to initiate efavirenz-based antiretroviral therapy (ART). Primary endpoints of TB disease-free survival 12 months after randomization (efficacy) and ≥ grade 3 adverse events (AEs) on treatment (safety) were compared, using a 6.6% noninferiority margin for efficacy. Randomization was stratified by site, pulmonary cavitation, and HIV status. PWH were enrolled in a staged fashion to support cautious evaluation of drug-drug interactions between rifapentine and efavirenz.

RESULTS

A total of 2516 participants from 13 countries in sub-Saharan Africa, Asia, and the Americas were enrolled. Among 194 (8%) microbiologically eligible PWH, the median CD4+ count was 344 cells/μL (interquartile range: 223-455). The rifapentine-moxifloxacin regimen was noninferior to control (absolute difference in unfavorable outcomes -7.4%; 95% confidence interval [CI] -20.8% to 6.0%); the rifapentine regimen was not noninferior to control (+7.5% [95% CI, -7.3% to +22.4%]). Fewer AEs were reported in rifapentine-based regimens (15%) than the control regimen (21%).

CONCLUSIONS

In people with HIV-associated DS-PTB with CD4+ counts ≥100 cells/μL on efavirenz-based ART, the 4-month daily rifapentine-moxifloxacin regimen was noninferior to the 6-month control regimen and was safe.

CLINICAL TRIALS REGISTRATION

NCT02410772.

Effects of rifampicin, CYP2B6 and ABCB1 polymorphisms on efavirenz plasma concentration in Chinese patients living with HIV and tuberculosis

BACKGROUND

Tuberculosis (TB) is the leading opportunistic infection of people living with human immunodeficiency virus (HIV; PLWH). Cytochrome P450 (CYP) 2B6 and ATP-binding cassette sub-family B member 1 (ABCB1) are involved in the metabolism and transportation of efavirenz. The study was aimed to investigate the effects of rifampicin, CYP2B6 and ABCB1 polymorphisms on efavirenz exposure in Chinese PLWH co-infected with TB.

METHOD

PLWH were screened according to inclusion and exclusion criteria and divided into HIV group and HIV/TB group. Efavirenz plasma concentration (C₀) was determined, dose-adjusted concentration (C₀/D) was calculated, and genotypes of CYP2B6 516G>T, 785A>G, and ABCB1 2677G>T, 3435C>T were analyzed.

RESULTS

252 PLWH were enrolled, including 75 co-infected with TB and concomitant with rifampicin. Efavirenz C₀ and C₀/D were both higher in HIV group (1.94 μg/mL, 0.2007 (μg/ml)/(mg/kg/d)) compared with HIV/TB group (1.52 μg/mL, 0.1557 (μg/ml)/(mg/kg/d)) (p = .001). Efavirenz C₀/D was significantly higher in patients with variant genotypes of CYP2B6 516G>T and 785A>G (p<.001), and was significantly lower in HIV/TB group compared with HIV group among patients with CYP2B6 516 GG, TT, and 785 AA, AG genotypes (p < .05).

CONCLUSION

Efavirenz exposure is reduced by co-administration with rifampicin, and related to genetic polymorphisms of CYP2B6.

Virological failure of antiretroviral therapy and associated social and clinical factors in children and adolescents living with HIV

   According to the World Health Organization, sustained virological suppression of 90 % should be achieved among children and adolescents living with HIV / AIDS, which makes it important to assess the prevalence of virological failure of antiretroviral therapy.   The aim of this study was to determine the prevalence of virological failure and the clinical factors associated with it, as well as therapeutic drug monitoring in groups divided by the viral load level among children and adolescents with HIV.   Materials and Methods: A retrospective analysis of the medical records of 184 children and adolescents receiving antiretroviral therapy and registered at the Irkutsk Regional Center for the Prevention and Control of AIDS and Infectious Diseases, Irkutsk, was carried out. The study included 172 children aged 1-18 years with perinatal HIV infection. Patients were divided into groups depending on the level of viral load: group 1 – 21 patients with viral load > 1000 copies/ml of plasma, group 2 – 42 patients with viral load 50– 1000 copies/ml of plasma, group 3 – 109 patients with undetectable viral load (< 50 copies/ml). All patients underwent standard tests in accordance with clinical guidelines for the treatment of HIV infection in children, as well as therapeutic drug monitoring.   Results. Against the background of ongoing antiretroviral therapy, a significant number of patients 21 / 172 (12,2 %) experienced virological failure. The proportion of children and adolescents with incomplete suppression of HIV replication is 42 / 172 (24,4 %). Statistically significant differences were obtained by changing the ART regimen (p = 0,031). In the first group, the proportion of patients who changed the therapy regimen is 7 / 21 (33,3 %), which is two times less than in the group with a zero viral load of 70 / 109 (64,2 %). There are differences in the proportion of children and adolescents with zero concentrations of ritonavir and lopinavir (p = 0,020 and p = 0,012) in the three compared groups. The distribution of patients with zero concentrations was as follows: for ritonavir in the first group 3 / 17 (17,6 %), in the second – 8/37 (21,6 %), in the third group – 4/80 (5 %); for lopinavir – 4/17 (23,5 %), 6/36 (16,7 %), 3/80 (3,8 %), respectively.   Conclusion. This study demonstrates that the prevalence of virological failure among children and adolescents receiving ART remains high. To achieve sustained virological suppression in children and adolescents taking a protease inhibitor regimen, adherence to therapy must be increased. As one of the methods for assessing adherence, therapeutic drug monitoring can be used.

Efavirenz: History, Development and Future

Efavirenz (Sustiva^®) is a first-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) used to treat human immunodeficiency virus (HIV) type 1 infection or to prevent the spread of HIV. In 1998, the FDA authorized efavirenz for the treatment of HIV-1 infection. Patients formerly required three 200 mg efavirenz capsules daily, which was rapidly updated to a 600 mg tablet that only required one tablet per day. However, when given 600 mg once daily, plasma efavirenz concentrations were linked not only to poor HIV suppression but also to toxicity. Clinical data suggested that the standard dose of efavirenz could be reduced without compromising its effectiveness, resulting in a reduction in side effects and making the drug more affordable. Therefore, ENCORE1 was performed to compare the efficiency and safeness of a reduced dose of efavirenz (400 mg) with the standard dose (600 mg) plus two NRTI in antiretroviral-naïve HIV-infected individuals. Nowadays, due to the emergence of integrase strand transfer inhibitors (INSTIs), some consider that it is time to stop using efavirenz as a first-line treatment on a global scale, in the parts of the world where that is possible. Efavirenz has been a primary first-line antiviral drug for more than 15 years. However, at this moment, the best use for efavirenz could be for pre-exposure prophylaxis (PrEP) and repurposing in medicine.

Outcomes of modern antiretroviral therapy in obese individuals living with HIV

Obesity is a global epidemic and people living with HIV (PLWH) are showing similar obesity trends to those in the general population. Obesity is manifested by several physiological features that can alter volume of distribution, elimination and metabolism of various medications including ART. Some drugs are increasingly prone to pharmacokinetic alteration during obesity depending on their physicochemical properties and clearance mechanism. These considerations raise concerns of hampered efficacy, development of resistance or increased toxicity of ART in PLWH. Here, we summarize available literature on the exposure and antiviral outcomes of currently available antiretroviral drugs in the context of obesity and provide a panel of recommendations for the clinical management and follow-up in this growing patient population.

Efavirenz Pharmacokinetics and Human Immunodeficiency Virus Type 1 (HIV-1) Viral Suppression Among Patients Receiving Tuberculosis Treatment Containing Daily High-Dose Rifapentine

BACKGROUND

A 4-month regimen containing rifapentine and moxifloxacin has noninferior efficacy compared to the standard 6-month regimen for drug-sensitive tuberculosis. We evaluated the effect of regimens containing daily, high-dose rifapentine on efavirenz pharmacokinetics and viral suppression in patients with human immunodeficiency virus (HIV)-associated tuberculosis (TB).

METHODS

In the context of a Phase 3 randomized controlled trial, HIV-positive individuals already virally suppressed on efavirenz--containing antiretroviral therapy (ART) (EFV1), or newly initiating efavirenz (EFV2) received TB treatment containing rifapentine (1200 mg), isoniazid, pyrazinamide, and either ethambutol or moxifloxacin. Mid-interval efavirenz concentrations were measured (a) during ART and TB cotreatment (Weeks 4, 8, 12, and 17, different by EFV group) and (b) when ART was taken alone (pre- or post-TB treatment, Weeks 0 and 22). Apparent oral clearance (CL/F) was estimated and compared. Target mid-interval efavirenz concentrations were > 1 mg/L. Co-treatment was considered acceptable if > 80% of participants had mid-interval efavirenz concentrations meeting this target.

RESULTS

EFV1 and EFV2 included 70 and 41 evaluable participants, respectively. The geometric mean ratio comparing efavirenz CL/F with vs without TB drugs was 0.79 (90% confidence interval [CI] .72-.85) in EFV1 and 0.84 [90% CI .69-.97] in EFV2. The percent of participants with mid-interval efavirenz concentrations > 1mg/L in EFV1 at Weeks 0, 4, 8, and 17 was 96%, 96%, 88%, and 89%, respectively. In EFV2, at approximately 4 and 8 weeks post efavirenz initiation, the value was 98%.

CONCLUSIONS

TB treatment containing high-dose daily rifapentine modestly decreased (rather than increased) efavirenz clearance and therapeutic targets were met supporting the use of efavirenz with these regimens, without dose adjustment.

CLINICAL TRIALS REGISTRATION

NCT02410772.

Constitutive androstane receptor and pregnane X receptor genotype influence efavirenz plasma concentration and CYP2B6 enzyme activity

Efavirenz is metabolized by CYP2B6, an inducible enzyme whose expression is regulated by the constitutive androstane receptor and pregnane X receptor nuclear receptors. CAR and PXR are encoded by genetically polymorphic NR1I2 and NR1I3, respectively. We examined the impact of NR1I2 and NR1I3 genotype on plasma EFV concentration and CYP2B6 enzyme activity among TB-HIV co-infected patients in Ethiopia. Treatment-naïve HIV patients with TB co-infection (n = 80) were enrolled and received first-line EFV-based antiretroviral and rifampicin-based anti-TB therapy. Plasma EFV and 8-hydroxy-EFV concentrations at the 4th and 16th week of EFV treatment were determined using LC/MS/MS. EFV/8-hydroxy-EFVmetabolic ratio was used as CYP2B6 metabolic activity index. In multivariate regression analysis, NR1I3 rs3003596C or NR1I2 rs2472677T variant allele carriers had significantly lower plasma EFV concentrations than non-carriers. Patients with NR1I2 rs3814057C/C genotype or NR1I3 rs3003596C allele carriers had significantly lower mean log EFV MR. Among CYP2B6*6 allele carriers, patients with NR1I3 rs2502815T/T or NR1I2 rs3814057C/C genotype had significantly lower mean log EFV MR. In conclusion, genetic variants in NR1I2 and NR1I3 genes influence plasma EFV exposure and CYP2B6 enzyme activity in TB-HIV co-infected patients on drug treatment.

Divergent effects of HIV reverse transcriptase inhibitors on pancreatic beta-cell function and survival: Potential role of oxidative stress and mitochondrial dysfunction

Antiretroviral therapy (ART), a life-saving treatment strategy in HIV/AIDS, has been implicated in increasing the risk of type 2 diabetes mellitus (T2DM). Direct damaging effects on beta-cell function and survival by either non-nucleoside reverse transcriptase inhibitors (NNRTIs) or nucleoside/tide reverse transcriptase inhibitors (NRTIs) may predispose individuals to developing T2DM or if already type 2 diabetic, to insulin dependency. The aim of this study was to investigate the effects of the NNRTIs efavirenz, rilpivirine and doravirine, and the NRTIs tenofovir disoproxil fumarate and emtricitabine, on beta-cell function and survival while suggesting potential cellular and molecular mechanism(s). Our results show contrasting effects within the NNRTI class as doravirine did not cause damaging effects in the rat insulinoma INS-1E cells while efavirenz and rilpivirine reduced insulin release and cell viability, and induced apoptosis in INS-1E cells. Additionally, efavirenz and rilpivirine increased ROS generation, disrupted Δψm and upregulated the mRNA and protein expression of CHOP and GRP78, key markers of endoplasmic reticulum stress. In silico docking studies predict a possible inhibition of the mitochondrial ATP synthase by rilpivirine. On the contrary, both the NRTIs tenofovir disoproxil fumarate and emtricitabine did not affect GSIS, cell viability and apoptosis/necrosis levels in INS-1E cells. The deleterious effects observed in beta-cells exposed to efavirenz or rilpivirine may be, at least partially, mediated by oxidative stress and mitochondrial toxicity. These findings provide potential mechanism(s) by which efavirenz and rilpivirine may contribute to the pathogenesis of T2DM and the progression of T2DM to insulin dependency in HIV-infected type 2 diabetics.

The Cyp2b6 Gene Polymorphism and Phenotypic Correlation of Efavirenz-Based Combination Therapy Among the Niger Delta Ethnic Population: Implications in Modern Pharmacogenomics

Purpose

DNA polymorphism describes the difference between individuals, groups, or ethnicities, races, etc., in terms of their DNA sequences or phenotypes as relates to drug metabolism. Using predictive genotyping of drug-metabolizing genes, we can develop individuals’ drug therapies that are less toxic and more effective. The main aim of the study was to evaluate genotype–phenotype-based correlation and incidence of genetic polymorphism of efavirenz blood levels among HIV/AIDS patients of the Niger Delta population.

Methods

A study questionnaire was designed to obtained patients’ data, blood samples were obtained, plasma was separated from the serum using a centrifuge for 5 minutes at 4000 rpm for HPLC analysis, polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis was conducted using Bsrl endonuclease enzyme to digest the PCR amplicons. Standard efavirenz was used at 0.5, 1, 2, 4, 16 mg/L to construct a calibration curve. Data were analyzed with SPSS software using chi-square test at p-value ≤0.5 and Microsoft excel 2013, while PCR and RFLP results were obtained after 1% Agarose gel electrophoresis, respectively.

Results

Phenotypic results showed that the participants had different efavirenz plasma concentrations. Six subjects (12%) had efavirenz plasma levels below 0.10 mg/L, considered ultra-rapid metabolizers (UMs), 22 (44%) 0.10 mg/L to 0.90 mg/L, classified as extensive metabolizers (EMs), 19 (38%) had 1.0 to 3.9 mg/L and were noted as intermediate metabolizers (IM), while 3 (6%) subjects showed efavirenz plasma levels from 4.0 mg/L to 6.0 mg/L, categorized as poor metabolizers (PM). RFLP results showed more than half of the population (56%) with a homozygous wild-type gene with CYP2B6*1*1 allele, 38% were CYP2B6*1*6 (heterozygous mutant) allele and 6% had homozygous mutant gene (CYP2B6*6*6 allele). Out of the 15 male subjects among the 50 patients that participated in the study, 8% were UM, 12% EM, 14% IM while no PM was observed, on the contrary, out of the 35 females participated in the study, 4% were observed as UM, 32% EM, 24% IM, while 6% were PM.

Conclusion

There was no significant difference (p ≤ 0.05) between genotype and phenotype data for CYP2B6 polymorphism, among the HIV/AIDS patients that participated in this study. Genetic polymorphism of the CYP2B6 gene is prevalent among HIV/AIDs patients in the Niger Delta ethnic population on efavirenz-based HAART treatment, as the population having homozygous mutant gene or PM are >1% (6%).

Frequencies of CYP2B6∗4,∗5, and ∗6 Alleles within an Iranian Population (Mazandaran)

Background

The human CYP2B subfamily consists of one functional gene (CYP2B6) and one pseudogene (CYP2B7P). Cytochrome P450 2B6 (CYP2B6) is a highly polymorphic enzyme that shows marked interindividual and interethnic variations. Currently, 38 alleles have been described, and some of the allelic variants have been associated with low enzyme activity. The aim of this study was to investigate the frequencies of CYP2B6^∗4, CYP2B6^∗5, and CYP2B6^∗6 alleles in the Mazani ethnic group among Iranian Population.

Methods

The study was conducted in 289 unrelated healthy volunteers. DNA was extracted from peripheral blood and analyzed by the PCR-RFLP protocol. The PCR product was digested with restriction enzymes and then separated using agarose gel electrophoresis.

Results

The frequency of CYP2B6^∗4, CYP2B6^∗5, and CYP2B6^∗6 in this study was 34.60%, 7.26%, and 34.54%, respectively.

Conclusion

The frequency of the CYP2B6^∗4 allele in the Mazani ethnic group was much higher (34.60%) than other population. The frequency of CYP2B6^∗6 (34.54%) also was higher than its frequency in other previously reported population. But the frequency of CYP2B6^∗5 in this study was lower than expected. These results will be useful in understanding the ethnic diversity in Iranian population and offer a preliminary basis for more rational use of drugs that are substrates for CYP2B6 in this population.

Effect of albumin and CYP2B6 polymorphisms on exposure of efavirenz: A population pharmacokinetic analysis in Chinese HIV-infected adults

BACKGROUND

Efavirenz is a vital component used to treat HIV-1 infection. Nevertheless, it shows large between-subject variability, which affects both its therapeutic response and adverse effects.

OBJECTIVE

To investigate the impact of gene polymorphisms and non-genetic factors on the variability of efavirenz pharmacokinetics and to propose the optimal dose regimens.

METHODS

A total of 769 plasma samples from 376 HIV-infected Han Chinese outpatients were collected to develop a population pharmacokinetic model using NONMEM software. The impact of patient demographics, laboratory tests, concomitant medication, and genetic polymorphisms of CYP2B6 and ABCB1 on efavirenz pharmacokinetics were explored. According to the final model, the model-informed dose optimization was conducted.

RESULTS

The pharmacokinetics of efavirenz was characterized by a one-compartment model with first-order absorption and elimination. The typical values of the estimated apparent oral clearance, volume of distribution, and absorption rate constant in the final model were 9.44 L/h, 200 L, and 0.727 h ^- 1, respectively. Efavirenz clearance was significantly influenced by CYP2B6 variants, including rs2099361, rs3745274, and rs2279343, along with albumin and weight. The volume of distribution was affected by albumin and weight. Based on the CYP2B6 polymorphisms of patients, the recommended daily doses of efavirenz were 100 mg for CYP2B6 slow metabolizers, 400 or 600 mg for intermediate metabolizers, and 800 or 1000 mg for extensive metabolizers.

CONCLUSIONS

Polymorphisms of CYP2B6, along with albumin and weight, resulted as the predictors of efavirenz pharmacokinetic variability, which could be used in prescribing optimal efavirenz doses.

Nose to brain delivery of Efavirenz nanosuspension for effective neuro AIDS therapy: in-vitro, in-vivo and pharmacokinetic assessment

Efavirenz is inhibitor of non-nucleoside reverse transcriptase enzyme; BCS class II drug. The objective of the present research was to prepare and evaluate nanosuspension of Efavirenz for the treatment of neuro-AIDS. Efavirenz is the substrate for drug resistant proteins at BBB prone to efflux and could not reach brain with effective levels. Current need of the therapy is to develop drug delivery systems targeting viral reservoirs at effective concentration in the brain. With this need we developed Efavirenz nanosuspension for nose to brain drug transport to bypass blood brain barrier. Nanosuspension prepared with high-pressure homogenization had a mean particle size of 223 nm, PDI of 0.2 and -21.2 mV zeta potential. Histopathology study on goat nasal mucosa showed no adverse effects of formulation on nasal tissues. Gamma scintigraphy study and in-vivo study on Wistar rat model reveals drug transport to the CNS after nasal administration. Pharmacokinetic parameters and drug targeting potential of 99.46 % suggest direct nose to brain transport of Efavirenz nanoparticle. Results reveal that nose to brain delivery of Efavirenz is the best possible alternative for neuro -AIDS treatment.

Vitamin D as Modulator of Drug Concentrations: A Study on Two Italian Cohorts of People Living with HIV Administered with Efavirenz

To date, vitamin D seems to have a significant role in affecting the prevention and immunomodulation in COVID-19 disease. Nevertheless, it is important to highlight that this pro-hormone has other several activities, such as affecting drug concentrations, since it regulates the expression of cytochrome P450 (CYP) genes. Efavirenz (EFV) pharmacokinetics is influenced by CYPs, but no data are available in the literature concerning the association among vitamin D levels, seasonality (which affects vitamin D concentrations) and EFV plasma levels. For this reason, the aim of this study was to evaluate the effect of 25-hydroxy vitamin D (25(OH)D3) levels on EFV plasma concentrations in different seasons. We quantified 25(OH)D3 by using chemiluminescence immunoassay, whereas EFV plasma concentrations were quantified with the HPLC–PDA method. A total of 316 patients were enrolled in Turin and Rome. Overall, 25(OH)D3levels resulted in being inversely correlated with EFV concentrations. Some patients with EFV levels higher than 4000 ng/mL showed a deficient 25(OH)D3 concentration in Turin and Rome cohorts and together. EFV concentrations were different in patients without vitamin D supplementation, whereas, for vitamin D-administered individuals, no difference in EFV exposure was present. Concerning seasonality, EFV concentrations were associated with 25(OH)D3 deficiency only in winter and in spring, whereas a significant influence was highlighted for 25(OH)D3 stratification for deficient, insufficient and sufficient values in winter, spring and summer. A strong and inverse association between 25(OH)D3and EFV plasma concentrations was suggested. These data suggest that vitamin D is able to affect drug exposure in different seasons; thus, the achievement of the clinical outcome could be improved by also considering this pro-hormone.

Associations between efavirenz concentrations, pharmacogenetics and neurocognitive performance in people living with HIV in Nigeria

OBJECTIVE

Efavirenz (EFV) use is associated with neuropsychiatric side effects, which may include poor neurocognitive performance. We evaluated single nucleotide polymorphisms in genes that contribute to EFV pharmacokinetics and examined them in association with EFV concentrations in plasma and hair, as well as neurocognitive performance.

DESIGN

Cross-sectional study in which adults with HIV receiving 600-mg EFV for at least 2 months were recruited and paired hair and dried blood spots (DBS) samples collected.

METHODS

Participants (N = 93, 70.3% female) were genotyped for seven single nucleotide polymorphisms in CYP2B6, NRII3 and ABCB1 using DBS. EFV was quantified in DBS and hair using validated liquid-chromatography-tandem-mass-spectrometry methods, with plasma EFV concentrations derived from DBS levels. Participants were also administered a neurocognitive battery of 10 tests (seven domains) that assessed total neurocognitive functioning.

RESULTS

Strong correlation (r = 0.66, P < 0.001) was observed between plasma and hair EFV concentrations. The median (interquartile range) hair EFV concentration was 6.85 ng/mg (4.56-10.93). CYP2B6 516G>T, (P < 0.001) and CYP2B6 983T>C (P = 0.001) were each associated with hair EFV concentrations. Similarly, 516G>T (P < 0.001) and 983T>C (P = 0.009) were significantly associated with plasma EFV concentration. No other genetic associations were observed. Contrary to other studies, total neurocognitive performance was significantly associated with plasma EFV concentrations (r = 0.23, P = 0.043) and 983T>C genotype (r = 0.38, P < 0.0005).

CONCLUSION

This study demonstrated approximately three-fold and two-fold higher EFV plasma and hair concentrations, respectively, among CYP2B6 516TT compared with 516GG. Higher EFV concentrations were associated with better neurocognitive performance, requiring further study to elucidate the relationships between adherence, adverse effects and outcomes.

Therapeutic drug monitoring study on the switch from coformulated 600-mg efavirenz, tenofovir disoproxil fumarate, and emtricitabine to coformulated 400-mg efavirenz, tenofovir disoproxil fumarate, and lamivudine among HIV-positive patients with viral suppression

OBJECTIVES

This study evaluated the efavirenz (EFV) mid-dose plasma concentration (C12), clinical efficacy, and safety after the switch to a single-tablet regimen containing tenofovir disoproxil fumarate (TDF), lamivudine (3TC), and 400-mg EFV in virally suppressed HIV-positive Taiwanese who were receiving co-formulated TDF, emtricitabine (FTC), and 600-mg EFV.

METHODS

In this single-arm, open-label study, HIV-positive adults who had undetectable plasma HIV RNA load (<50 copies/ml) for 6 months or longer while receiving co-formulated TDF, FTC, and 600-mg EFV with EFV C12 of ≥1 mg/L were enrolled. The participants were switched to co-formulated TDF, 3TC, and 400-mg EFV and followed for 24 weeks. The primary endpoint was the proportion of participants with EFV C12 ≥ 1 mg/L at Week 4. The secondary endpoints included virologic response and change of CD4 lymphocyte count up to Week 24. Specific adverse effects associated with EFV were recorded before and after the switch.

RESULTS

From December 2018 to January 2019, 50 participants were enrolled. EFV C12 remained ≥1 mg/L in 48 (96.0%) participants with a median reduction of 38.9% (interquartile range 29.0-44.4) at Week 4 after switch. All participants had undetectable plasma HIV RNA by Week 12, whereas 96.0% of them remained so at Week 24. Significant increases of CD4 lymphocyte count were observed at Weeks 12 and 24. Thirty-three participants (66.0%) reported improvement of pre-existing adverse effects.

CONCLUSION

Switch to coformulated TDF, 3TC, and 400-mg EFV in virally suppressed HIV-positive Taiwanese maintained effective EFV concentration and viral suppression while the adverse effects were reduced.

Untimed Efavirenz Drug Levels After Switching From Brand to Generic Formulations: A Short Communication

BACKGROUND

In British Columbia, antiretrovirals are distributed at no cost to patients via a publicly funded program, using generic formulations if available. A generic efavirenz-emtricitabine-tenofovir DF (EFV-FTC-TDF) combination pill became available in April 2018. The authors compared EFV untimed drug levels in subjects switching from brand to generic EFV-FTC-TDF.

METHODS

Archived plasma HIV viral load samples were identified for consenting participants who switched from brand to generic EFV-FTC-TDF; 3 preswitch and 2-3 postswitch samples, collected ≥1 month apart were assessed for each subject. "Untimed" EFV concentrations with unknown dosing and collection time were assessed using a validated liquid chromatography-tandem mass spectrometry method. Participants' mean, minimum, and maximum EFV levels were compared using the Wilcoxon signed rank test. Participants with EFV levels in the range associated with lower risks of virologic failure and central nervous system toxicity (1000-4000 ng/mL), preswitch and postswitch, were enumerated.

RESULTS

EFV levels were assessed in 297 preswitch and 249 postswitch samples from 99 participants, having exposure to brand and generic EFV for a median of 103 (Q1-Q3: 87-116) and 10.3 (Q1-Q3: 8.9-11.7) months, respectively. The final brand sample was collected at a median of 98 days preswitch; the first generic sample was collected at a median of 133 days postswitch. No significant differences were observed in participant mean EFV levels before (median 1968 ng/mL; Q1-Q3: 1534-2878 ng/mL) and after (median 1987 ng/mL; Q1-Q3: 1521-2834 ng/mL) switch (P = 0.85). Eighty participants had mean EFV levels within the 1000-4000 ng/mL range on the brand drug, of which 74 remained within this range postswitch.

CONCLUSIONS

There were no statistically significant differences between untimed EFV levels in patients switching from the brand to generic EFV combination pill. Given the long elimination half-life of EFV, untimed drug levels may be a convenient way to estimate product bioequivalence.

Large variability in plasma efavirenz concentration in Papua New Guinea HIV/AIDS patients associated with high frequency of CYP2B6 516T allele

Papua New Guinea (PNG) has a high HIV/AIDS prevalence and very high frequency of the CYP2B6 c.516G>T (rs3745274) variant. We have conducted the first investigation of the impact of c.516G>T and patient demographics on plasma efavirenz (EFV) and 8‐hydroxyefavirenz (8OH‐EFV) concentrations, metabolic ratio (8OH‐EFV/EFV) (MR), and their association with adverse effects, in PNG patients with HIV/AIDS. For 156 PNG patients with HIV/AIDS taking EFV 600 mg/day (for 3–156 months), plasma EFV and 8OH‐EFV concentrations were quantified, CYP2B6 c.516G>T genotyped, and demographic and self‐reported adverse effects data recorded. Genotype differences in EFV and 8OH‐EFV concentrations, MR, and percent within therapeutic range (1000–4000 ng/ml) were examined, in addition to EFV and 8OH‐EFV concentration differences between patients experiencing adverse effects. CYP2B6 c.516T allele frequency was 53%. Plasma EFV (p < 0.0001), 8OH‐EFV (p < 0.01), and MR (p < 0.0001) differed significantly between genotypes, with genotype explaining 38%, 10%, and 50% of variability, respectively. Plasma EFV concentrations were significantly higher in T/T (median = 5168 ng/ml) than G/G (1036 ng/ml, post hoc p < 0.0001) and G/T (1502 ng/ml, p < 0.0001) genotypes, with all patients above therapeutic range (n = 23) being T/T genotype (p < 0.0001). EFV and 8OH‐EFV concentrations were not significantly higher in patients experiencing adverse effects. In PNG HIV/AIDS population where the 516T frequency is very high, it explains a substantial portion of variability (38%) in EFV disposition; however, at least for the patients receiving EFV long term, this does not translate into significant side effects.

Improvement in depressive symptoms after antiretroviral therapy initiation in people with HIV in Rakai, Uganda

Depression is common following HIV infection and often improves after ART initiation. We aimed to identify distinct dimensions of depression that change following ART initiation in persons with HIV (PWH) with minimal comorbidities (e.g., illicit substance use) and no psychiatric medication use. We expected that dimensional changes in improvements in depression would differ across PWH. In an observational cohort in Rakai, Uganda, 312 PWH (51% male; mean age = 35.6 years) completed the Center for Epidemiologic Studies-Depression (CES-D) scale before and up to 2 years after ART initiation. Twenty-two percent were depressed (CES-D scores ≥ 16) pre-ART that decreased to 8% after ART. All CES-D items were used in a latent class analysis to identify subgroups with similar change phenotypes. Two improvement phenotypes were identified: affective-symptom improvement (n = 58, 19%) and mixed-symptom improvement (effort, appetite, irritability; n = 41, 13%). The affect-improvement subgroup improved on the greatest proportion of symptoms (76%). A third subgroup was classified as no-symptom changes (n = 213, 68%) as they showed no difference is symptom manifestation from baseline (93% did not meet depression criteria) to post-ART. Factors associated with subgroup membership in the adjusted regression analysis included pre-ART self-reported functional capacity, CD4 count, underweight BMI, hypertension, female sex(P's < 0.05). In a subset of PWH with CSF, subgroup differences were seen on Aβ-42, IL-13, and IL-12. Findings support that depression generally improves following ART initiation; however, when improvement is seen the patterns of symptom improvement differ across PWH. Further exploration of this heterogeneity and its biological underpinning is needed to evaluate potential therapeutic implications of these differences.

Influence of SULT1A1*2 Polymorphism on Plasma Efavirenz Concentration in Thai HIV-1 Patients

Purpose

Plasma efavirenz (EFV) concentrations within therapeutic levels are essential to successfully treat patients suffering from human immunodeficiency virus (HIV) type 1. In addition to the drug-metabolizing enzyme CYP2B6, other phase II drug-metabolizing enzymes and transporters may have an important role in the pharmacokinetics of EFV. Thus, the influence of phase II drug-metabolizing enzymes and drug transporters on plasma EFV levels was investigated in Thai HIV patients receiving EFV.

Patients and Methods

Genotyping was performed by TaqMan^® real-time PCR in 149 HIV-infected Thai adults, and plasma efavirenz concentration was measured by a validated high-performance liquid chromatography in 12 hours after dosing steady-state plasma samples at week 12 and 24.

Results

Patients with three or more copies of SULT1A1 had significantly lower median plasma EFV concentrations than those carrying two copies at week 12 (p=0.046) and SULT1A1*2 (c.638G>A) carriers had significantly lower median plasma EFV concentrations compared to those not carrying the variant at week 24 (p=0.048). However, no significant association was found after adjusting for CYP2B6 genotype.

Conclusion

Genetic variation in a combination of SULT1A1*2 and SULT1A1 copy number may contribute to variability in EFV metabolism and thereby may impact drug response. The influence of a combination between the SULT1A1 and CYP2B6 genotype on EFV pharmacokinetics should be further investigated in a larger study population.

Low antileishmanial drug exposure in HIV-positive visceral leishmaniasis patients on antiretrovirals: an Ethiopian cohort study

Background

Despite high HIV co-infection prevalence in Ethiopian visceral leishmaniasis (VL) patients, the adequacy of antileishmanial drug exposure in this population and effect of HIV-VL co-morbidity on pharmacokinetics of antileishmanial and antiretroviral (ARV) drugs is still unknown.

Methods

HIV-VL co-infected patients received the recommended liposomal amphotericin B (LAmB) monotherapy (total dose 40 mg/kg over 24 days) or combination therapy of LAmB (total dose 30 mg/kg over 11 days) plus 28 days 100 mg/day miltefosine, with possibility to extend treatment for another cycle. Miltefosine, total amphotericin B and ARV concentrations were determined in dried blood spots or plasma using LC–MS/MS.

Results

Median (IQR) amphotericin B C_max on Day 1 was 24.6 μg/mL (17.0–34.9 μg/mL), which increased to 40.9 (25.4–53.1) and 33.2 (29.0–46.6) μg/mL on the last day of combination and monotherapy, respectively. Day 28 miltefosine concentration was 18.7 (15.4–22.5) μg/mL. Miltefosine exposure correlated with amphotericin B accumulation. ARV concentrations were generally stable during antileishmanial treatment, although efavirenz C_min was below the 1 μg/mL therapeutic target for many patients.

Conclusions

This study demonstrates that antileishmanial drug exposure was low in this cohort of HIV co-infected VL patients. Amphotericin B C_max was 2-fold lower than previously observed in non-VL patients. Miltefosine exposure in HIV-VL co-infected patients was 35% lower compared with adult VL patients in Eastern Africa, only partially explained by a 19% lower dose, possibly warranting a dose adjustment. Adequate drug exposure in these HIV-VL co-infected patients is especially important given the high proportion of relapses.

Instability of Efavirenz Metabolites Identified During Method Development and Validation

Accurate quantification of efavirenz metabolites in patient samples is required to investigate their potential contribution to efavirenz adverse events. This study aimed to validate a LC-MS/MS method to quantify and investigate the stability of efavirenz and metabolites in human plasma. Compounds were extracted from plasma by supported liquid extraction and resolved on a C18 column. Validation was performed following FDA bioanalytical method validation guidelines. Stability under common conditions of sample pre-treatment and storage were assessed. Efavirenz and 8-hydroxyefavirenz were stable for all conditions tested. 7-Hydroxyefavirenz and 8,14-dihydroxyefavirenz were not stable in plasma at room temperature for 24 h (46%-69% loss), -20°C for 90 days (17%-50% loss), or 60°C for 1 h (90%-95% loss). Efavirenz and 8-hydroxyefavirenz concentrations in HIV/AIDS patient (n=5) plasma prepared from pre-treated (60°C for 1 h) whole blood varied from 517-8564 ng/mL and 131-813 ng/mL, respectively. 7-Hydroxyefavirenz and 8,14-dihydroxyefavirenz concentrations were below validated lower limits of quantification (0.25 and 0.5 ng/mL, respectively), most likely due to sample pre-treatment. This is the first report of 7-hydroxyefavirenz and 8,14-dihydroxyefavirenz instability under conditions commonly used in preparation of samples from HIV/AIDS patients. Alternative biosafety measures to heat pre-treatment must therefore be used for accurate quantification of plasma 7-hydroxyefavirenz and 8,14-dihydroxyefavirenz.

Effect of high-dose rifampicin on efavirenz pharmacokinetics: drug-drug interaction randomized trial

BACKGROUND

High-dose rifampicin is considered to shorten anti-TB treatment duration but its effect on antiretroviral metabolism is unknown.

OBJECTIVES

To assess the effect of doubling the rifampicin dose (to 20 mg/kg/day, R20) on efavirenz pharmacokinetics (PK) in HIV/TB coinfected patients.

METHODS

Open-label Phase 2 drug-drug interaction randomized trial. Pulmonary TB, ART-naive adults were randomized to R20 and either efavirenz 600 mg (EFV600) or 800 mg (EFV800), or rifampicin 10 mg/kg/day (R10) and EFV600 with a 1:1:1 ratio. Patients were first started on TB treatment and 2-4 weeks later started on ART. They were switched to R10 and EFV600 after 8 weeks. Full PK sampling was done 4 weeks (on rifampicin) and 24 weeks (off rifampicin) after ART initiation. Transaminases, plasma HIV-1 RNA and sputum cultures were monitored. The efavirenz geometric mean ratio (GMR) of AUC at 4 and 24 weeks after ART initiation within the same patient was calculated in each arm and its 90% CI was compared with a preset range (0.70-1.43).

RESULTS

Of 98 enrolled patients (32 in the R20EFV600 arm, 33 in the R20EFV800 arm and 33 in the R10EFV600 arm), 87 had full PK sampling. For the R20EFV600, R20EFV800 and R10EFV600 arms, GMRs of efavirenz AUC were 0.87 (90% CI: 0.75-1.00), 1.12 (90% CI: 0.96-1.30) and 0.96 (90% CI: 0.84-1.10). Twelve weeks after ART initiation, 78.6%, 77.4% and 72.4% of patients had HIV-1 RNA below 100 copies/mL and 85.7%, 86.7% and 80.0% had Week 8 culture conversion, respectively. Two patients per arm experienced a severe increase in transaminases.

CONCLUSIONS

Doubling the rifampicin dose had a small effect on efavirenz concentrations and was well tolerated.

Characterization, in vitro dissolution, and pharmacokinetics of different batches of efavirenz raw materials

OBJECTIVE

To perform the solid-state characterization and the in vitro-in vivo correlation (IVIVC) of three batches of efavirenz (EFV) active pharmaceutical ingredients.

SIGNIFICANCE

EFV is an effective anti-HIV drug. Due to the poor aqueous solubility, the rate and extent of EFV absorption deeply depend on its dissolution characteristics.

METHODS

Thermal analyses, x-ray diffraction, and particle size distribution were performed. The saturation solubility and dissolution profiles were assessed in 0.5% (w/v) sodium lauryl sulfate (SLS), fasted-state simulated intestinal fluid (FaSSIF), and fed-state simulated intestinal fluid (FeSSIF) using a flow-through cell. Each batch was orally administered to Wistar rats and the pharmacokinetic parameters were correlated with those obtained from in vitro dissolution.

RESULTS

All batches of EFV consisted polymorph I. EFV-A presented the lowest particle size distribution [d(v,0.5) = 197.8 µm; d(v,0.9) = 444.6 µm] followed by EFV-B [d(v,0.5) = 223.9 µm; d(v,0.9) = 481.1 µm], and EFV-C [d(v,0.5) = 240.8 µm; d(v,0.9) = 497.3 µm]. The saturated solubility in FaSSIF was 36% and 40% of that in FeSSIF and SLS, respectively. EFV-A presented the fastest rate and largest extension of dissolution than EFV-B and C (79.15%, 69.93% and 54.22%, respectively, as well as the highest maximum plasma concentration. Levels B, C, and multiple-C of IVIVC models were achieved.

CONCLUSION

The FaSSIF medium discriminated the dissolution profiles of EFV APIs. Small differences in particle size distribution had a significant impact on the biopharmaceutical parameters of EFV, suggesting that strict control of such parameter is an important aspect during API development and drug formulation.

Impact of Therapeutic Drug Monitoring of Antiretroviral Drugs in Routine Clinical Management of People Living With HIV: A Narrative Review

BACKGROUND

The treatment of HIV infection has evolved significantly since the advent of highly active antiretroviral therapy. As a result, a response rate of 90%-95% now represents a realistically achievable target. Given this background, it is difficult to imagine the additional benefits that therapeutic drug monitoring (TDM) could provide in the management of HIV infection.

METHODS

This article is not intended to provide a systematic literature review on TDM of antiretroviral agents; rather, the authors aim to discuss the potential added value of TDM in the optimal management of people living with HIV (PLWH) in selected real-life clinical scenarios based on data collected over 10 years by their TDM service.

RESULTS

Some clinical situations, in which the selection of the optimal antiretroviral therapy is challenging, have been identified. These include poorly compliant patients, suboptimal antiretroviral therapies (in terms of both efficacy and toxicity), polypharmacy with a high risk of drug-drug interactions, and different patient populations, such as pregnant women.

CONCLUSIONS

The transformation of HIV infection from a near-universally fatal illness to a lifelong chronic disease has resulted in an HIV population that is growing and aging, placing new and increasing demands on public programs and health services. Increasingly, the management of comorbidities, polypharmacy, and drug-drug interaction, and their impact on antiretroviral therapy will have to be undertaken. These clinical settings represent some of the new frontiers for the use of TDM with the goal of achieving optimal prescription and outcome for PLWH.

Association of Hair Concentrations of Antiretrovirals with Virologic Outcomes Among People Living with HIV in Guangxi, China

BACKGROUND

Hair concentrations of antiretrovirals are an innovative and non-invasive method for measuring cumulative antiretroviral exposure and assessing long-term antiretroviral adherence. This study aimed to examine hair concentrations of antiretrovirals in relation to virologic outcomes among PLHIV in Guangxi, China.

METHODS

Cross-sectional data of hair concentrations of antiretrovirals and HIV viral load were collected from 215 PLHIV in Guangxi, China. Multivariate logistic regression analyses were used to examine the association of hair concentrations of antiretrovirals with virologic outcomes.

RESULTS

Of the 215 participants, 215, 67, and 163 PLHIV are receiving lamivudine, zidovudine, and efavirenz, respectively. Multivariate analysis revealed that hair concentrations of lamivudine [odds ratio = 16.52, 95% CI 2.51-108.60, p = 0.004] and efavirenz [odds ratio = 14.26, 95% CI 1.18-172.01, p = 0.036], but not zidovudine [odds ratio = 1.77, 95% CI 0.06-56.14, p = 0.747], were the strongest independent predictor of virologic suppression when controlling for sociodemographic and other HIV-related characteristics.

CONCLUSION

Hair concentrations of lamivudine and efavirenz were the strongest independent predictor of virologic suppression among Chinese PLHIV. Hair analysis of antiretrovirals may provide a non-invasive, cost-effective tool that predicts virologic suppression among PLHIV in China.

Antiretroviral Drugs Impact Autophagy with Toxic Outcomes

Antiretroviral drugs have dramatically improved the morbidity and mortality of people living with HIV (PLWH). While current antiretroviral therapy (ART) regimens are generally well-tolerated, risks for side effects and toxicity remain as PLWH must take life-long medications. Antiretroviral drugs impact autophagy, an intracellular proteolytic process that eliminates debris and foreign material, provides nutrients for metabolism, and performs quality control to maintain cell homeostasis. Toxicity and adverse events associated with antiretrovirals may be due, in part, to their impacts on autophagy. A more complete understanding of the effects on autophagy is essential for developing antiretroviral drugs with decreased off target effects, meaning those unrelated to viral suppression, to minimize toxicity for PLWH. This review summarizes the findings and highlights the gaps in our knowledge of the impacts of antiretroviral drugs on autophagy.

Pharmacokinetics and Drug-Drug Interactions of Isoniazid and Efavirenz in Pregnant Women Living With HIV in High TB Incidence Settings: Importance of Genotyping

The World Health Organization guidelines recommend that individuals living with HIV receive ≥ 6 months of isoniazid preventive therapy, including pregnant women. Yet, plasma isoniazid exposure during pregnancy, in the antiretroviral therapy era, has not been well-described. We investigated pregnancy-induced and pharmacogenetic-associated pharmacokinetic changes and drug-drug interactions between isoniazid and efavirenz in pregnant women. Eight hundred forty-seven women received isoniazid for 28 weeks, either during pregnancy or at 12 weeks postpartum, and 786 women received efavirenz. After adjusting for NAT2 and CYP2B6 genotype and weight, pregnancy increased isoniazid and efavirenz clearance by 26% and 15%, respectively. Isoniazid decreased efavirenz clearance by 7% in CYP2B6 normal metabolizers and 13% in slow and intermediate metabolizers. Overall, both isoniazid and efavirenz exposures were reduced during pregnancy, but the main determinants of drug concentration were NAT2 and CYP2B6 genotypes, which resulted in a five-fold difference for both drugs between rapid and slow metabolizers.

Pharmacokinetic parameters and weight change in HIV patients newly switched to dolutegravir-based regimens in SIMPL'HIV clinical trial

This study aims to evaluate the association between dolutegravir (DTG) pharmacokinetic parameters and weight changes in treatment-experienced people with HIV (PWHIV) from the Simpl'HIV study newly switched to a dual DTG-based regimen. We used multivariable linear regressions to evaluate the association between DTG pharmacokinetic parameters at week 48 (derived using an established model) and weight change between week 0 and week 48. We adjusted our model for potential confounders including CD4 nadir, female sex, African origin, age, weight at week 0 and presence of a non-nucleoside reverse transcriptase inhibitor-based regimen before switch to DTG. The analysis included data from 39 PWHIV. An average significant weight gain of 2.4 kg was observed between baseline and week 48. DTG plasma exposure was not significantly associated with weight gain, even after adjusting for potential confounders (P = .9). We found no significant association between DTG pharmacokinetic parameters and weight gain amongst PWHIV newly switched to a DTG-based dual regimen.

Beneficial and Adverse Effects of cART Affect Neurocognitive Function in HIV-1 Infection: Balancing Viral Suppression against Neuronal Stress and Injury

HIV-associated neurocognitive disorders (HAND) persist despite the successful introduction of combination antiretroviral therapy (cART). While insufficient concentration of certain antiretrovirals (ARV) may lead to incomplete viral suppression in the brain, many ARVs are found to cause neuropsychiatric adverse effects, indicating their penetration into the central nervous system (CNS). Several lines of evidence suggest shared critical roles of oxidative and endoplasmic reticulum stress, compromised neuronal energy homeostasis, and autophagy in the promotion of neuronal dysfunction associated with both HIV-1 infection and long-term cART or ARV use. As the lifespans of HIV patients are increased, unique challenges have surfaced. Longer lives convey prolonged exposure of the CNS to viral toxins, neurotoxic ARVs, polypharmacy with prescribed or illicit drug use, and age-related diseases. All of these factors can contribute to increased risks for the development of neuropsychiatric conditions and cognitive impairment, which can significantly impact patient well-being, cART adherence, and overall health outcome. Strategies to increase the penetration of cART into the brain to lower viral toxicity may detrimentally increase ARV neurotoxicity and neuropsychiatric adverse effects. As clinicians attempt to control peripheral viremia in an aging population of HIV-infected patients, they must navigate an increasingly complex myriad of comorbidities, pharmacogenetics, drug-drug interactions, and psychiatric and cognitive dysfunction. Here we review in comparison to the neuropathological effects of HIV-1 the available information on neuropsychiatric adverse effects and neurotoxicity of clinically used ARV and cART. It appears altogether that future cART aiming at controlling HIV-1 in the CNS and preventing HAND will require an intricate balancing act of suppressing viral replication while minimizing neurotoxicity, impairment of neurocognition, and neuropsychiatric adverse effects. Graphical abstract Schematic summary of the effects exerted on the brain and neurocognitive function by HIV-1 infection, comorbidities, psychostimulatory, illicit drugs, therapeutic drugs, such as antiretrovirals, the resulting polypharmacy and aging, as well as the potential interactions of all these factors.

The association between cigarette smoking and efavirenz plasma concentration using the population pharmacokinetic approach

AIMS

Efavirenz is still widely used as the preferred first-line antiretroviral agent in middle- and low-income countries, including Malaysia. The efavirenz population pharmacokinetic profile among HIV-positive smokers is still unknown. We aimed to assess the association of smoking with efavirenz and the differences in HIV clinical outcomes.

METHODS

A total of 154 stable HIV-positive patients on efavirenz in northern Malaysia were recruited with a sparse sampling for this multicentre prospective cohort study. The association between smoking and efavirenz pharmacokinetic parameters was determined using the nonlinear mixed-effect model. A mixture model of clearance was adopted to describe the metaboliser status because genetic data are unavailable. The effect of smoking on HIV clinical markers (CD4, CD4/CD8 ratio and viral blips) for at least 2 years after the antiretroviral initiation was also investigated.

RESULTS

Our data were best fitted with a 1-compartment mixture model with first-order absorption without lag time. Smoking significantly associated with higher clearance (β = 1.39; 95% confidence interval: 1.07 to 1.91), while weight affected both clearance and volume. From the mixture model, 20% of patients were in the slow clearance group, which mimic the genotype distribution of slow metaboliser. An efavirenz dose reduction is not recommended for smokers ≥60 kg with normal metabolism rate. Smoking significantly associated with slower normalisation of CD4 and CD4/CD8 ratio.

CONCLUSIONS

HIV-positive smokers presented with significantly higher efavirenz clearance and unfavourable clinical outcomes. Close monitoring of adherence and clinical response among smokers is warranted.

Pharmacodynamics of efavirenz 400 mg in treatment-naïve Chinese HIV-infected patients in a prospective cohort study

BACKGROUND

The plasma concentration of patients treated with efavirenz (EFV) 600 mg was found to exceed the upper limit of the proposed therapeutic window in most Chinese HIV-infected individuals; thus, dosage reduction of EFV to 400 mg daily warranted consideration. This study aimed to assess the pharmacodynamics of EFV 400 mg for HIV-1-infected patients in China.

METHOD

Twenty cART-naïve individuals were enrolled in this study. EFV 400 mg combined with tenofovir (TDF) and lamivudine (3TC) as an initial antiretroviral regimen was administered for 48 weeks. EFV concentration and T cell subsets as well as HIV RNA load were evaluated at baseline and at 4, 12, 24, and 48 weeks. Moreover, neuropsychiatric adverse effects were also assessed by the Hamilton depression (HAMD) scale and Pittsburgh sleep quality index (PSQI).

RESULTS

Eighteen males and two females whose median age was 26 (interquartile range [IQR]: 23-32) years completed 48 weeks of follow-up. The median EFV concentrations were 1.88 (IQR: 1.54-2.42), 1.74 (IQR: 1.36-1.93), 1.93 (IQR: 1.66-2.22), and 1.85 (IQR: 1.54-2.14) mg/L at weeks 4, 12, 24, and 48, respectively. The viral load was 4.59 (IQR: 4.10-5.19) log₁₀ copies/mL at baseline, and it decreased by 4.6 (IQR: 3.98-5.18) log₁₀ copies/mL from baseline to week 48. Three of 20 (15%), 10 of 20 (50.0%), 17 of 20 (85%), and 18 of 19 (95%) participants had a plasma viral load less than 50 copies/mL at weeks 4, 12, 24, and 48, respectively. The median CD4 cell count was 330 (IQR: 237-410) cells/μL at baseline, and it increased to 473 (IQR: 344-574) cells/μL at 48 weeks. The HAMD score was 5 (IQR: 3-9.8) and 3 (IQR: 2.25-4) at baseline and 48 weeks, respectively. The PSQI score was 4 (IQR: 2-5.8) and 3 (IQR: 2-4) at baseline and 48 weeks, respectively. Dizziness was the most common event, occurring in 70% of patients within the first 2 weeks of treatment.

CONCLUSION

Patients prescribed with EFV 400 mg-containing agents demonstrated favourable virological and immunological responses. And the plasma EFV concentration was within the recommended therapeutic range, with fewer adverse reactions than with EFV 600 mg. EFV 400 mg was effective and safe in Chinese HIV-infected patients.

TRIAL REGISTRATION

NCT04596488 ; Registered 21 October, 2020; Retrospectively registered.

Starting or Switching to an Integrase Inhibitor-Based Regimen Affects PTSD Symptoms in Women with HIV

As the use of Integrase inhibitor (INSTI)-class antiretroviral medications becomes more common to maintain long-term viral suppression, early reports suggest the potential for CNS side-effects when starting or switching to an INSTI-based regimen. In a population already at higher risk for developing mood and anxiety disorders, these drugs may have significant effects on PTSD scale symptom scores, particularly in women with HIV (WWH). A total of 551 participants were included after completing ≥ 1 WIHS study visits before and after starting/switching to an INSTI-based ART regimen. Of these, 14% were ART naïve, the remainder switched from primarily a protease inhibitor (PI) or non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen. Using multivariable linear mixed effects models, we compared PTSD Civilian Checklist subscale scores before and after a "start/switch" to dolutegravir (DTG), raltegravir (RAL), or elvitegravir (EVG). Start/switch to EVG improved re-experiencing subscale symptoms (P's < 0.05). Switching to EVG improved symptoms of avoidance (P = 0.01). Starting RAL improved arousal subscale symptoms (P = 0.03); however, switching to RAL worsened re-experiencing subscale symptoms (P < 0.005). Starting DTG worsened avoidance subscale symptoms (P = 0.03), whereas switching to DTG did not change subscale or overall PTSD symptoms (P's > 0.08). In WWH, an EVG-based ART regimen is associated with improved PTSD symptoms, in both treatment naïve patients and those switching from other ART. While a RAL-based regimen was associated with better PTSD symptoms than in treatment naïve patients, switching onto a RAL-based regimen was associated with worse PTSD symptoms. DTG-based regimens either did not affect, or worsened symptoms, in both naïve and switch patients. Further studies are needed to determine mechanisms underlying differential effects of EVG, RAL and DTG on stress symptoms in WWH.

Efavirenz Loaded Nanostructured Lipid Carriers for Efficient and Prolonged Viral Inhibition in HIV-Infected Macrophages

Background: The clinical outcome of anti-HIV therapy is poor due to the inherent fallouts ofanti-HIV therapy. It is further worsened due to the presence of viral reservoirs in immune cellslike the macrophages. An ideal anti-HIV therapy must reach, deliver the drug and exert itsaction inside macrophages. To address this, we developed novel cationic nanostructured lipidcarriers of efavirenz (cationic EFV-NLC). Methods: The developed cationic EFV NLCs were evaluated for particle size, zeta potential,encapsulation efficiency, in-vitro drug release, DSC, XRD, TEM, cytotoxicity, cellular uptakestudies and anti-HIV efficacy in a monocyte-derived macrophage cell line (THP-1). Results: Cationic EFV-NLCs showed high encapsulation efficiency (90.54 ± 1.7%), uniformparticle size distribution (PDI 0.3-0.5 range) and high colloidal stability with positive zetapotential (+23.86 ± 0.49 mV). DSC and XRD studies confirmed the encapsulation of EFVwithin NLCs. Cytotoxicity studies (MTT assay) revealed excellent cytocompatibility (CC5013.23 ± 0.54 μg/mL). Fluorescence microscopy confirmed the efficient uptake of cationic EFVNLCs,while flow cytometry revealed time and concentration dependant uptake within THP-1cells. Cationic EFV-NLCs showed higher retention and sustained release with 2.32-fold higherpercent inhibition of HIV-1 in infected macrophages as compared to EFV solution at equimolarconcentrations. Interestingly, they demonstrated 1.23-fold superior anti-HIV efficacy over EFVloadedNLCs at equimolar concentrations. Conclusion: Cationic NLCs were capable of inhibiting the viral replication at higher limitsconsistently for 6 days suggesting successful prevention of HIV-1 replication in infectedmacrophages and thus can prove to be an attractive tool for promising anti-HIV therapy.

Pharmacological data of a successful 4-days-a-week regimen in HIV antiretroviral therapy (ANRS 162-4D trial)

INTRODUCTION

Few data are available on plasma concentrations of antiretroviral therapy (ARV) during intermittent treatment.

OBJECTIVE

To compare plasma concentrations in OFF vs ON treatment periods at several time points during treatment.

METHODS

During a successful 48-week multicenter study (ANRS 162-4D trial) of 4 days with treatment (ON) followed by 3 days without treatment (OFF) in adults treated by two nucleoside analogues and a third agent belonging to a boosted protease-inhibitor (PI, darunavir [DRV], atazanavir [ATV], lopinavir [LPV]) or a non-nucleoside-reverse-transcriptase inhibitor (NNRTI, efavirenz [EFV], etravirine [ETR], rilpivirine [RPV]) conducted in 100 patients (96% success), we determined the plasma concentrations of ARV. Blood samples were collected for analysis at inclusion (W0, 7/7 strategy for all patients), W16 and W40 (ON) and at W4, W8, W12, W24, W32 and W48 (OFF).

RESULTS

A total of 866 samples was analysed. Plasma concentrations were not statistically lower after 4 days (ON) vs 7/7 days of treatment except for RPV (-30 ng/mL at 4/7, P = 0.003). Significant lower plasma concentrations were observed for OFF vs ON except for ETR (n = 5, P = 0.062). Overall, 87.1% of ON concentrations (ATV 92.1%, DRV 51.1%, LPV 62.5%, EFV 94.4%, ETR 100% and RPV 94.9%) and 21.8% of OFF concentrations (ATV 1.4%, DRV 0.0%, LPV 0.0%, EFV 16.0%, ETR 92.6% and RPV 39.0%) were above the theoretical limit of efficacy of the molecule. In the OFF period, 85.8% of PI concentrations were under the limit of quantification, while 98.0% of NNRTI concentrations were quantifiable.

CONCLUSION

Despite low/undetectable PI/NNRTI plasma concentrations in the OFF period, patients maintained an undetectable viral load. The mechanistic explanation should be investigated.