Atazanavir/ritonavir-based combination antiretroviral therapy for treatment of HIV-1 infection in adults

A systematic review assessing the association of inflammatory markers with kidney dysfunction in people living with HIV on highly active antiretroviral therapy

Monitoring chronic diseases, particularly kidney disorders, in people living with HIV (PLWH) is of paramount importance. Here, a systematic search was conducted across electronic search engine and databases like PubMed, Scopus, and Google Scholar, from date of inception until December 2023, to identify pertinent studies reporting on any association between inflammation and kidney function in PLWH. Only six clinical studies in peer-reviewed journals met the inclusion criteria, involving 1467 participants aged 37 to 51, with approximately 17% being females. The report emphasizes the potential impact of highly active antiretroviral therapy (HAART) on kidney function in PLWH, highlighting the significance of monitoring inflammation markers as indicators of kidney function, even when HAART is effective. Acknowledging study limitations, particularly the scarcity of relevant research, the findings highlight a need for more research to inform on clinical guidance to optimize HIV management, particularly regarding kidney health and HAART regimens. Although very limited studies were evaluated, the study lays an important foundation for future research to uncover the complex relationship between HAART, inflammation markers, and kidney health in PLWH.

Enhanced antifungal activity of posaconazole against Candida auris by HIV protease inhibitors, atazanavir and saquinavir

The increasing incidence and dissemination of multidrug-resistant Candida auris represents a serious global threat. The emergence of pan-resistant C. auris exhibiting resistance to all three classes of antifungals magnifies the need for novel therapeutic interventions. We identified that two HIV protease inhibitors, atazanavir and saquinavir, in combination with posaconazole exhibited potent activity against C. auris in vitro and in vivo. Both atazanavir and saquinavir exhibited a remarkable synergistic activity with posaconazole against all tested C. auris isolates and other medically important Candida species. In a time-kill assay, both drugs restored the fungistatic activity of posaconazole, resulting in reduction of 5 and 5.6 log10, respectively. Furthermore, in contrast to the individual drugs, the two combinations effectively inhibited the biofilm formation of C. auris by 66.2 and 81.2%, respectively. Finally, the efficacy of the two combinations were tested in a mouse model of C. auris infection. The atazanavir/posaconazole and saquinavir/posaconazole combinations significantly reduced the C. auris burden in mice kidneys by 2.04- (99.1%) and 1.44-log10 (96.4%) colony forming unit, respectively. Altogether, these results suggest that the combination of posaconazole with the HIV protease inhibitors warrants further investigation as a new therapeutic regimen for the treatment of C. auris infections.

Expression of CYP2B6 Enzyme in Human Liver Tissue of HIV and HCV Patients

Background and Objectives: Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections present significant public health challenges worldwide. The management of these infections is complicated by the need for antiviral and antiretroviral therapies, which are influenced by drug metabolism mediated by metabolic enzymes and transporters. This study focuses on the gene expression of CYP2B6, CYP3A4, and ABCB1 transporters in patients with HIV, HCV, and HIV/HCV co-infection, aiming to assess their potential association with the choice of therapy, patohistological and clinical parameters of liver damage such as the stage of liver fibrosis, serum levels of ALT and AST, as well as the grade of liver inflammation and other available biochemical parameters. Materials and Methods: The study included 54 patients who underwent liver biopsy, divided into HIV-infected, HCV-infected, and co-infected groups. The mRNA levels of CYP2B6, CYP3A4, and ABCB1 was quantified and compared between the groups, along with the analysis of liver fibrosis and inflammation levels. Results: The results indicated a significant increase in CYP2B6 mRNA levels in co-infected patients, a significant association with the presence of HIV infection with an increase in CYP3A4 mRNA levels. A trend towards downregulation of ABCB1 expression was observed in patients using lamivudine. Conclusions: This study provides insight into gene expression of CYP2B6 CYP3A4, and ABCB1 in HIV, HCV, and HIV/HCV co-infected patients. The absence of correlation with liver damage, inflammation, and specific treatment interventions emphasises the need for additional research to elucidate the complex interplay between gene expression, viral co-infection, liver pathology, and therapeutic responses in these particular patients population.

Will the Use of Pharmacogenetics Improve Treatment Efficiency in COVID-19?

The COVID-19 pandemic is associated with a global health crisis and the greatest challenge for scientists and doctors. The virus causes severe acute respiratory syndrome with an outcome that is fatal in more vulnerable populations. Due to the need to find an efficient treatment in a short time, there were several drugs that were repurposed or repositioned for COVID-19. There are many types of available COVID-19 therapies, including antiviral agents (remdesivir, lopinavir/ritonavir, oseltamivir), antibiotics (azithromycin), antiparasitics (chloroquine, hydroxychloroquine, ivermectin), and corticosteroids (dexamethasone). A combination of antivirals with various mechanisms of action may be more efficient. However, the use of some of these medicines can be related to the occurrence of adverse effects. Some promising drug candidates have been found to be ineffective in clinical trials. The knowledge of pharmacogenetic issues, which translate into variability in drug conversion from prodrug into drug, metabolism as well as transport, could help to predict treatment efficiency and the occurrence of adverse effects in patients. However, many drugs used for the treatment of COVID-19 have not undergone pharmacogenetic studies, perhaps as a result of the lack of time.

Evaluation of cardiotoxicity and other adverse effects associated with concomitant administration of artemether/lumefantrine and atazanavir/ritonavir-based antiretroviral regimen in patients living with HIV

The interplay of artemether-lumefantrine (AL) and atazanavir-ritonavir (ATVr) with Cytochrome P (CYP) 3A4 isoenzyme and QTc-interval may spawn clinically significant drug interactions when administered concomitantly. Cardiotoxicity and other adverse effects associated with interaction between AL and ATVr were evaluated in patients with HIV infection and malaria comorbidity. In a two-arm parallel study design, six doses of AL 80/480 mg were administered to 20 participants [control-arm (n = 10) and ATVr-arm (n = 10)], having uncomplicated Falciparum malaria, at intervals of 0, 8, 24, 36, 48 and 60 h respectively. Participants in the control arm took only AL while those in ATVr-arm took both AL and ATVr-based ART regimen. Electrocardiography, adverse events monitoring and blood tests were carried out for each of them at pre and post doses of AL. Data obtained were analyzed. QTc-interval was significantly increased in the ATVr-arm (0.4079 ± 0.008 to 0.4215 ± 0.007 s, p = 0.008) but not in the control-arm (0.4016 ± 0.018 to 0.4024 ± 0.014 s, p = 0.962). All values were, however, within normal range [0.36 – 0.44 / 0.46 s (male/female)]. General body weakness and chest pain were new adverse events reported, at post-dose of AL, in the ATVr-arm but not in the control-arm. There was no significant change (p > 0.05) in the plasma levels of creatinine, alanine aminotransferase, aspartate aminotransferase and hemoglobin at post-dose compared to pre-dose of AL in both arms of study. Concomitant administration of artemether-lumefantrine with atazanavir-ritonavir-based regimen is potentially cardiotoxic but not associated with clinically significant renal, blood nor liver toxicities. They must be used with caution.

Impact of Simulated Intestinal Fluids on Dissolution, Solution Chemistry, and Membrane Transport of Amorphous Multidrug Formulations

The solution behavior and membrane transport of multidrug formulations were herein investigated in a biorelevant medium simulating fasted conditions. Amorphous multidrug formulations were prepared by the solvent evaporation method. Combinations of atazanavir (ATV) and ritonavir (RTV) and felodipine (FDN) and indapamide (IPM) were prepared and stabilized by a polymer for studying their dissolution (under non-sink conditions) and membrane transport in fasted state simulated intestinal fluid (FaSSIF). The micellar solubilization by FaSSIF enhanced the amorphous solubility of the drugs to different extents. Similar to buffer, the maximum achievable concentration of drugs in combination was reduced in FaSSIF, but the extent of reduction was affected by the degree of FaSSIF solubilization. Dissolution studies of ATV and IPM revealed that the amorphous solubility of these two drugs was not affected by FaSSIF solubilization. In contrast, RTV was significantly affected by FaSSIF solubilization with a 30% reduction in the maximum achievable concentration upon combination to ATV, compared to 50% reduction in buffer. This positive deviation by FaSSIF solubilization was not reflected in the mass transport–time profiles. Interestingly, FDN concentrations remain constant until the amount of IPM added was over 1000 μg/mL. No decrease in the membrane transport of FDN was observed for a 1:1 M ratio of FDN-IPM combination. This study demonstrates the importance of studying amorphous multidrug formulations under physiologically relevant conditions to obtain insights into the performance of these formulations after oral administration.

Predicting Drug-Drug Interactions between Rifampicin and Ritonavir-Boosted Atazanavir Using PBPK Modelling

Objectives

The aim of this study was to simulate the drug–drug interaction (DDI) between ritonavir-boosted atazanavir (ATV/r) and rifampicin (RIF) using physiologically based pharmacokinetic (PBPK) modelling, and to predict suitable dose adjustments for ATV/r for the treatment of people living with HIV (PLWH) co-infected with tuberculosis.

Methods

A whole-body DDI PBPK model was designed using Simbiology 9.6.0 (MATLAB R2019a) and verified against reported clinical data for all drugs administered alone and concomitantly. The model contained the induction mechanisms of RIF and ritonavir (RTV), the inhibition effect of RTV for the enzymes involved in the DDI, and the induction and inhibition mechanisms of RIF and RTV on the uptake and efflux hepatic transporters. The model was considered verified if the observed versus predicted pharmacokinetic values were within twofold. Alternative ATV/r dosing regimens were simulated to achieve the trough concentration (C_trough) clinical cut-off of 150 ng/mL.

Results

The PBPK model was successfully verified according to the criteria. Simulation of different dose adjustments predicted that a change in regimen to twice-daily ATV/r (300/100 or 300/200 mg) may alleviate the induction effect of RIF on ATV C_trough, with > 95% of individuals predicted to achieve C_trough above the clinical cut-off.

Conclusions

The developed PBPK model characterized the induction-mediated DDI between RIF and ATV/r, accurately predicting the reduction of ATV plasma concentrations in line with observed clinical data. A change in the ATV/r dosing regimen from once-daily to twice-daily was predicted to mitigate the effect of the DDI on the C_trough of ATV, maintaining plasma concentration levels above the therapeutic threshold for most patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-021-01067-1.

UGT1A1 regulatory variant with potential effect on efficacy of HIV and cancer drugs commonly prescribed in South Africa

Aim: Despite the high disease burden of human immunodeficiency virus (HIV) infection and colorectal cancer (CRC) in South Africa (SA), treatment-relevant pharmacogenetic variants are understudied. Materials & methods: Using publicly available genotype and gene expression data, a bioinformatic pipeline was developed to identify liver expression quantitative trait loci (eQTLs). Results: A novel cis-eQTL, rs28967009, was identified for UGT1A1, which is predicted to upregulate UGT1A1 expression thereby potentially affecting the metabolism of dolutegravir and irinotecan, which are extensively prescribed in SA for HIV and colorectal cancer treatment, respectively. Conclusion: As increased UGT1A1 expression could affect the clinical outcome of dolutegravir and irinotecan treatment by increasing drug clearance, patients with the rs28967009A variant may require increased drug doses to reach therapeutic levels or should be prescribed alternative drugs.

Current evidence for the risk of PR prolongation, QRS widening, QT prolongation, from lopinavir, ritonavir, atazanavir, and saquinavir: A systematic review

BACKGROUND

Lopinavir, ritonavir, atazanavir, and saquinavir had been reportedly used or suggested for coronavirus disease 2019 (COVID-19) treatment. They may cause electrocardiography changes. We aim to evaluate risk of PR prolongation, QRS widening, and QT prolongation from lopinavir, ritonavir, atazanavir, and saquinavir.

METHODS

In accordance with preferred reporting items for systematic reviews and meta-analyses guidelines, our search was conducted in PubMed Central, PubMed, EBSCOhost, and ProQuest from inception to June 25, 2020. Titles and abstracts were reviewed for relevance. Cochrane Risk of Bias Tool 2.0 and Downs and Black criteria was used to evaluate quality of studies.

RESULTS

We retrieved 9 articles. Most randomized controlled trials have low risk of biases while all quasi-experimental studies have a positive rating. Four studies reporting PR prolongation however only 2 studies with PR interval >200 ms. One of which, reported its association after treatment with ritonavir-boosted saquinavir treatment while another, during treatment with ritonavir-boosted atazanavir. No study reported QRS widening >120 ms with treatment. Four studies reporting QT prolongation, with only one study reaching QT interval >450 ms after ritonavir-boosted saquinavir treatment on healthy patients. There is only one study on COVID-19 patients reporting QT prolongation in 1 out of 95 patients after ritonavir-boosted lopinavir treatment.

CONCLUSION

Limited evidence suggests that lopinavir, ritonavir, atazanavir, and saquinavir could cause PR prolongation, QRS widening, and QT prolongation. Further trials with closer monitoring and assessment of electrocardiography are needed to ascertain usage safety of antivirals in COVID-19 era.

DFT investigation of atazanavir as potential inhibitor for 2019-nCoV coronavirus M protease

Atazanavir (ATZ) is an antiviral drug synthesized.ATZ is being investigated for potential application against the Coronavirus 2019-nCoV. To find candidate drugs for 2019-nCoV, we have carried out a computational study to screen for effective available drug ATZ which may work as an inhibitor for the Mpro of 2019-nCoV. In the present work, the first time the molecular structure of ATZ molecule has been studied using Density Functional Theory (CAMB3LYP/6-31G*) in solvent water. The electronic properties, atomic charges, MEP, NBO analysis, and excitation energies of ATZ have also been studied. The interaction of ATZ compound with the Coronavirus was performed by molecular docking studies.

Serum Lipid Profiles of Patients Taking Efavirenz-Based Antiretroviral Regimen Compared to Ritonavir-Boosted Atazanavir with an Optimized Background at Zewditu Memorial Hospital, Addis Ababa, Ethiopia

Background

Dyslipidemia represents significant health care concerns in patients taking antiretroviral therapy due to their association with cardiovascular disease risk. There is limited data regarding the effects of boosted atazanavir (ATV/r) treatment in the lipid profiles of Ethiopian HIV patients. Thus, this study compares the mean values of lipid profile differences of HIV patients on ATV/r-based regimen compared to efavirenz (EFV)-based regimen, while the background is Tenofovir Disoproxil Fumarate/lamivudine.

Materials and Methods

A comparative hospital-based cross-sectional study was conducted among adult HIV-infected patients at Zewditu Memorial Hospital, Addis Ababa, Ethiopia, from July–September 2017. An equal number of EFV and ATV/r-treated patients (n=90 each) receiving for 1-year and over were included in the study. Serum total cholesterol (TC), triglyceride (TG), gigh-density lipoprotein cholesterol (HDL-c), and low-density lipoprotein cholesterol (LDL-c) were measured. Data comparison used chi-square test, Student’s t-test and Mann–Whitney U-test. Multivariate logistic regression analysis and p-value<0.05 were used to identify associated factors of serum lipid profiles.

Results

In the present study, the ATV/r-treated group results were significantly higher in the median values of TG [207 (56–1094) vs 145 (42–768) mg/dL; p=0.001] and the mean value of TG/HDL-c (6.6 vs 4.4; p=0.001) as compared to the EFV-treated group. The EFV-treated group showed significantly higher in the mean value of HDL-c (44.7 vs 38.7 mg/dL; p=0.001) as compared to the ATV/r-treated group. Body mass index was associate with LDL and HDL. CD4 was associated with TC. Current antiretroviral therapy was associated with TG. Duration of HIV since first diagnosis and duration of ART were associated with HDL.

Conclusion

ATV/r is associated with elevated in TG and TG/HDL-C, but low HDL as compared to EFV. Differences in LDL or HDL that were found were of unclear clinical significance. The long-term significance is unknown.

Carbamate group as structural motif in drugs: a review of carbamate derivatives used as therapeutic agents

Due to their very good chemical and proteolytic stability, ability to penetrate cell membranes, and resemblance to a peptide bond, carbamate derivatives have received much attention in recent years and got an important role in modern drug discovery and medicinal chemistry. Today, carbamates make structural and/or functional part of many drugs and prodrugs approved and marketed for the treatment of various diseases such as cancer, epilepsy, hepatitis C, HIV infection, and Alzheimer's disease. In drugs they can play a role in drug-target interaction or improve the biological activity of parent molecules. In prodrugs they are mainly used to delay first-pass metabolism and enhance the bioavailability and effectiveness of compounds. This brief review takes a look at the properties and use of carbamates in various fields of medicine and provides quick insights into the mechanisms of action for some of them.

Important Pharmacogenetic Information for Drugs Prescribed During the SARS-CoV-2 Infection (COVID-19)

In December 2019, the severe acute respiratory syndrome virus-2 pandemic began, causing the coronavirus disease 2019. A vast variety of drugs is being used off-label as potential therapies. Many of the repurposed drugs have clinical pharmacogenetic guidelines available with therapeutic recommendations when prescribed as indicated on the drug label. The aim of this review is to provide a comprehensive summary of pharmacogenetic biomarkers available for these drugs, which may help to prescribe them more safely.

Current Computational Approaches for the Development of Anti-HIV Inhibitors: An Overview

BACKGROUND

Today, HIV-1 infection has become an extensive problem to public health and a greater challenge to all working researchers throughout the world. Since the beginning of HIV-1 virus, several antiviral therapeutic agents have been developed at various stages to combat HIV-1 infection. But, many of antiviral drugs are on the platform of drug resistance and toxicology issues, needs an urgent constructive investigation for the development of productive and protective therapeutics to make an improvement of individual life suffering with viral infection. As developing a novel agent is very costly, challenging and time taking route in the recent times.

METHODS

The review summarized about the modern approaches of computational aided drug discovery to developing a novel inhibitor within a short period of time and less cost.

RESULTS

The outcome suggests on the premise of reported information that the computational drug discovery is a powerful technology to design a defensive and fruitful therapeutic agents to combat HIV-1 infection and recover the lifespan of suffering one.

CONCLUSION

Based on survey of the reported information, we concluded that the current computational approaches is highly supportive in the progress of drug discovery and controlling the viral infection.

Therapeutic management of HIV-infected patients with chronic kidney disease

CKD and HIV infection are two chronic diseases impacting heavily on the survival of the affected patients. The interplay between HIV infection and chronic kidney disease (CKD) is complex and interactions occur at multiple levels. Approach to the management of HIV-infected patients requires special attention to face the numerous therapeutic difficulties ranging from drug-drug interactions to drug-toxicity. The most effective strategy is targeted to suppression of HIV viral load, as it dramatically changes the prognosis of the patients as well as prevents the development of HIV-associated kidney disease. As shown in this review, the approach to the therapeutic management of CKD in the setting of HIV infection varies in relation to the degree of renal impairment.

Antiretroviral Drug Metabolism in Humanized PXR-CAR-CYP3A-NOG Mice

Antiretroviral drug (ARV) metabolism is linked largely to hepatic cytochrome P450 activity. One ARV drug class known to be metabolized by intestinal and hepatic CYP3A are the protease inhibitors (PIs). Plasma drug concentrations are boosted by CYP3A inhibitors such as cobisistat and ritonavir (RTV). Studies of such drug-drug interactions are limited since the enzyme pathways are human specific. While immune-deficient mice reconstituted with human cells are an excellent model to study ARVs during human immunodeficiency virus type 1 (HIV-1) infection, they cannot reflect human drug metabolism. Thus, we created a mouse strain with the human pregnane X receptor, constitutive androstane receptor, and CYP3A4/7 genes on a NOD.Cg-Prkdc^scid Il2rg^tm1Sug/JicTac background (hCYP3A-NOG) and used them to evaluate the impact of human CYP3A metabolism on ARV pharmacokinetics. In proof-of-concept studies we used nanoformulated atazanavir (nanoATV) with or without RTV. NOG and hCYP3A-NOG mice were treated weekly with 50 mg/kg nanoATV alone or boosted with nanoformulated ritonavir (nanoATV/r). Plasma was collected weekly and liver was collected at 28 days post-treatment. Plasma and liver atazanavir (ATV) concentrations in nanoATV/r-treated hCYP3A-NOG mice were 2- to 4-fold higher than in replicate NOG mice. RTV enhanced plasma and liver ATV concentrations 3-fold in hCYP3A-NOG mice and 1.7-fold in NOG mice. The results indicate that human CYP3A-mediated drug metabolism is reduced compared with mouse and that RTV differentially affects human gene activity. These differences can affect responses to PIs in humanized mouse models of HIV-1 infection. Importantly, hCYP3A-NOG mice reconstituted with human immune cells can be used for bench-to-bedside translation.

Naringin prevents HIV-1 protease inhibitors-induced metabolic complications in vivo

Background

Insulin resistance, glucose intolerance and overt diabetes are known metabolic complications associated with chronic use of HIV-Protease Inhibitors. Naringin is a grapefruit-derived flavonoid with anti-diabetic, anti-dyslipidemia, anti-inflammatory and anti-oxidant activities.

Objectives

The study investigated the protective effects of naringin on glucose intolerance and impaired insulin secretion and signaling in vivo.

Methods

Male Wistar rats were divided into six groups (n = 6) and were daily orally treated with distilled water {3.0 ml/kg body weight (BW)}, atazanavir (133 mg/kg BW), saquinavir (333 mg/kg BW) with or without naringin (50 mg/kg BW), respectively for 56 days. Body weights and water consumption were recorded daily. Glucose tolerance tests were carried out on day 55 of the treatment and thereafter, the rats were sacrificed by halothane overdose.

Results

Atazanavir (ATV)- or saquinavir (SQV)-treated rats exhibited significant weight loss, polydipsia, elevated Fasting blood glucose (FBG), reduced Fasting Plasma Insulin (FPI) and expression of phosphorylated, Insulin Receptor Substrate-1 (IRS-1) and Akt proteins, hepatic and pancreatic glucokinase levels, and also increasing pancreatic caspase-3 and -9 as well as UCP2 protein expressions compared to controls, respectively. These effects were completely reversed by naringin treatment.

Conclusion

Naringin prevents PI-induced glucose intolerance and impairment of insulin signaling and as nutritional supplement it could therefore alleviate metabolic complications associated with antiretroviral therapy.

Determination of irinotecan, SN-38 and SN-38 glucuronide using HPLC/MS/MS: Application in a clinical pharmacokinetic and personalized medicine in colorectal cancer patients

BACKGROUND

Irinotecan (CPT-11) is chemotherapy used mainly in the metastatic colorectal cancer. The purpose of this study was to develop and validate the LC-MS/MS for the simultaneous determination of CPT-11, SN-38, and SN-38G.

METHODS

A 100 μL of plasma was prepared after protein precipitation and analyzed on a C18 column using 0.1% acetic acid in water and 0.1% acetic acid in acetonitrile as mobile phases. The mass spectrometer worked with multiple reaction monitoring (MRM) in positive scan mode. The standard curves were linear on a concentration range of 5-10 000 ng/mL for CPT-11, 5-1000 ng/mL for SN-38, and 8-1000 ng/mL for SN-38G.

RESULTS

In this assay, the intra and interday precision consisted of ≤9.11% and ≤11.29% for CPT-11, ≤8.70% and 8.31% for SN-38, and ≤9.90 and 9.64% for SN-38G.

CONCLUSION

This method was successfully used to quantify CPT-11, SN-38, and SN-38G and applied to a pharmacokinetic study.

Evaluating an enhanced adherence intervention among HIV positive adolescents failing atazanavir/ritonavir-based second line antiretroviral treatment at a public health clinic

Sustaining virological suppression among HIV-infected adolescents is challenging. We evaluated a home-based adherence intervention and characterized self-reported adherence, virological response and drug resistance among adolescents failing atazanavir/ritonavir (ATV/r)-based 2^nd line treatment.

Effects of a switch from tenofovir- to abacavir-based antiretroviral therapy, with or without atazanavir, on renal function

Introduction

Tenofovir disoproxil fumarate (TDF)–associated renal dysfunction may abate when TDF is replaced with abacavir (ABC). The extent to which the third drug atazanavir contributes to renal dysfunction is unclear.

Methods

A retrospective analysis was conducted on adults who had plasma viral load (pVL)<200 copies/mL for≥six months while receiving TDF/lamivudine (3TC) – or TDF/emtricitabine (FTC)–based antiretroviral therapy (ART), then switched to ABC/3TC while retaining the third drug in the ART regimen. CD4, pVL, creatinine, estimated glomerular filtration rate (eGFR), serum phosphorus, urine albumin to creatinine ratio and serum lipids were compared between pre-switch baseline and 3, 6 and 12 months after the switch to ABC.

Results

A total of 286 patients switched from TDF to ABC between 2004 and 2014: 232 (81%) male, median age 48 years (interquartile range (IQR) 42, 56). The third drug was atazanavir (± ritonavir) in 141 (49%) cases. The pVL was<50 copies/mL in 93 to 96% at all time points. Median serum creatinine was 93 µmol/L (IQR 80–111) at baseline and decreased to 88 µmol/L (IQR 78–98) at 12 months after the switch to ABC. Median eGFR increased from 74 (IQR 60–88) mL/min at baseline to 80 mL/min (IQR 69–89) at 12 months. Results were not significantly different between patients on atazanavir versus those on another third drug.

Conclusions

Viral suppression was maintained among patients who switched from TDF/3TC or TDF/FTC to ABC/3TC. Serum creatinine and eGFR improved up to 12 months after switching to ABC/3TC, irrespective of whether or not patients were also receiving atazanavir±ritonavir.

Safety of darunavir and atazanavir in HIV-infected children in Europe and Thailand

BACKGROUND

Surveillance for mid- and long-term antiretroviral therapy (ART) toxicity in children is important for informing treatment guidelines. We assessed the safety of darunavir (DRV) and atazanavir (ATV), commonly used as second-line protease inhibitors following lopinavir/ritonavir, in Europe and Thailand.

METHODS

Cohorts contributed individual patient data on adverse events (AE) in those aged <18 years taking DRV and ATV, respectively, to 02/2014. Rates of Division of AIDS (DAIDS) grade ≥3 laboratory AEs were calculated.

RESULTS

Of 431 patients on DRV and 372 on ATV, 317 (74%) and 301 (81%), respectively, had weight and dose data available, of whom 56 (18%) and 33 (9%) took the drugs at a non-approved age or dose. Median age at DRV and ATV start was 14.8 years (IQR 12.8-16.1) and 13.5 years (11.4-15.2); 43% and 26% had received ≥8 ART drugs previously. Overall rates of grade ≥3 AEs for absolute neutrophils, total cholesterol, triglycerides, pancreatic amylase, lipase and alanine aminotransferase (ALT) were ≤3/100 person-years (PY) on approved doses of both drugs, but 66/100 PY (95% CI 52, 84) for bilirubin after <12 months on ATV declining to 32/100 PY (95% CI 23, 44) after >24 months. Five serious drug-related clinical AEs were reported in four patients on ATV (one discontinued) and three in three patients on DRV (all discontinued), and did not substantially differ in those on approved compared to non-approved doses. Proportions on the drugs at last follow-up were 89% (383/431) for DRV and 81% (301/372) for ATV (including 73/92 with grade ≥3 hyperbilirubinaemia).

CONCLUSIONS

AEs were few in number and comparable for the two drugs, with the exception of high rates of hyperbilirubinaemia for ATV; few patients discontinued due to toxicity.

Maintenance of virologic efficacy and decrease in levels of β2-microglobulin, soluble CD40L and soluble CD14 after switching previously treated HIV-infected patients to an NRTI-sparing dual therapy

Novel strategies are necessary to decrease inflammatory parameters in successfully treated HIV-infected patients. Our aim was to evaluate the maintenance of viral suppression and potential changes in inflammatory, immune-activation and coagulation biomarkers in virologically suppressed HIV-infected patients switched to a nucleoside reverse transcriptase inhibitor-sparing (NRTI) and maraviroc (MVC)-containing combined antiretroviral therapy (cART). Fifty-eight HIV-infected patients were observed after their treatment regimens were changed to MVC 150mg/once daily plus ritonavir-boosted protease inhibitor therapy. Activation-, inflammation- and coagulation-associated biomarkers and mitochondrial (mt)DNA were analyzed after a median of 24weeks of follow-up. We observed that after changing to an NRTI-sparing regimen, 96.6% of HIV-patients on viral suppressive cART maintained viral suppression and their CD4+ T cell counts did not change significantly (median of 31weeks of follow-up). This cART switch reduced soluble CD40 ligand (p=0.002), beta-2 microglobulin (p=0.025), and soluble CD14 (p=0.009) in patients with higher baseline levels of these inflammation biomarkers after a median of 24weeks of follow-up. The results of our study show that changing to NRTI-sparing dual therapy decreased the levels of inflammatory biomarkers and maintained the immune-virologic efficacy. The potential benefits of this regimen warrant further investigation to uncover the association of this therapy with the potential decrease in the morbidity and mortality of HIV-infected patients from non-AIDS-defining illnesses.

Moving away from Ritonavir, Abacavir, Tenofovir, and Efavirenz (RATE)--agents that concern prescribers and patients: a feasibility study and call for a trial

Objectives

Regimens sparing RATE (ritonavir, abacavir, tenofovir, efavirienz) agents might have better long-term safety. We conducted a feasibility exercise to assess the potential for a randomised trial evaluating RATE-sparing regimens.

Design

Observational.

Methods

We first calculated RATE-sparing options available to an average patient receiving RATE agents. We reviewed treatment history and all resistance assays from patients attending the St. Vincent’s Hospital (Sydney) clinic and receiving ≥2 RATE agents (n = 120). A viable RATE-sparing regimen with 2 or 3 fully-active agents was constructed from the following six ‘safer’ agents: rilpivirine or etravirine; atazanavir; raltegravir; maraviroc; and lamivudine. Activity for each drug was predicted as 1 (full-activity), 0.5 or 0 (no activity) using the Stanford mutation database. The utility of maraviroc was calculated assuming both maraviroc activity and inactivity where unknown. The analysis was restricted to regimens for which supporting evidence was identified in the literature or conference proceedings. Finally, we calculated the proportion of patients in the nationally representative Australian HIV Observational Database (AHOD) cohort receiving ≥2 RATE agents (n = 1473) to measure the potential population-level uptake of RATE-sparing agents.

Results

Assuming full maraviroc activity, 117(97.5%) and 107(89.2%) individuals had at least one option with 2 or 3 active RATE-sparing agents, respectively. Assuming no maraviroc activity this decreased to 113(94.2%) and 104(86.7%), respectively. In AHOD, 837(56.8%) patients were receiving ≥2 RATE agents.

Conclusion

Feasible treatment switch options sparing RATE agents exist for the majority of patients. Understanding the pros and cons of switching stable patients onto new RATE-sparing regimens requires evidence derived from randomised controlled trials.

Revealing the metabolic sites of atazanavir in human by parallel administrations of D-atazanavir analogs

Atazanavir (Reyataz(®)) is an important member of the HIV protease inhibitor class. Because of the complexity of its chemical structure, metabolite identification and structural elucidation face serious challenges. So far, only seven non-conjugated metabolites in human plasma have been reported, and their structural elucidation is not complete, especially for the major metabolites produced by oxidations. To probe the exact sites of metabolism and to elucidate the relationship among in vivo metabolites of atazanavir, we designed and performed two sets of experiments. The first set of experiments was to determine atazanavir metabolites in human plasma by LC-MS, from which more than a dozen metabolites were discovered, including seven new ones that have not been reported. The second set involved deuterium labeling on potential metabolic sites to generate D-atazanavir analogs. D-atazanavir analogs were dosed to human in parallel with atazanavir. Metabolites of D-atazanavir were identified by the same LC-MS method, and the results were compared with those of atazanavir. A metabolite structure can be readily elucidated by comparing the results of the analogs and the pathway by which the metabolite is formed can be proposed with confidence. Experimental results demonstrated that oxidation is the most common metabolic pathway of atazanavir, resulting in the formation of six metabolites of monooxidation (M1, M2, M7, M8, M13, and M14) and four of dioxidation (M15, M16, M17, and M18). The second metabolic pathway is hydrolysis, and the third is N-dealkylation. Metabolites produced by hydrolysis include M3, M4, and M19. Metabolites formed by N-dealkylation are M5, M6a, and M6b.

Related factors to atazanavir plasma levels in a cohort of HIV positive individuals with undetectable viral load

Objective

To evaluate the factors associated with plasma concentrations of atazanavir (ATV) in a cohort of well-controlled HIV infected subjects (undetectable viremia).

Design

Cross-sectional study where 69 subjects were consecutively enrolled between April and November, 2011.

Methods

Patients had to be on atazanavir for at least six months, undetectable viral load for a period equal to or longer than 12 months, T CD4+ lymphocyte count higher than 200 cells/mm³, and aged between 18 years and 70 years old. Exclusion criteria were pregnancy, any neurologic disease, active opportunistic disease, hepatitis or cancer. Atazanavir plasma levels were measured by ultra-performance liquid chromatography.

Results and discussion

Overall, 54 patients (mean age of 47 years and 50% women) were included in the analysis. Those without ritonavir (unboosted atazanavir) had statistically lower plasma concentrations than those with ritonavir boosted atazanavir (p = 0.001) and total and indirect bilirubin were statistically associated with plasma concentration of atazanavir (r = 0.32 and r = 0.33 respectively; p < 0.05 in both cases). No statistical association was found among gender, ethnicity, age, weight, body mass index (BMI), lipid profile, and the plasma concentration of atazanavir.

Conclusion

In summary, as expected, concomitant ritonavir use was the only factor associated with atazanavir plasma levels. Prospective studies with a larger sample size might help to observe an association of atazanavir concentrations to other characteristics such as body weight, since the p-value showed to be close to significance (p = 0.068).

Identification and structural elucidation of in vitro metabolites of atazanavir by HPLC and tandem mass spectrometry

Atazanavir (marketed as Reyataz®) is an important member of the human immunodeficiency virus protease inhibitor class. LC-UV-MS(n) experiments were designed to identify metabolites of atazanavir after incubations in human hepatocytes. Five major (M1-M5) and seven minor (M7-M12) metabolites were identified. The most abundant metabolite, M1, was formed by a mono-oxidation on the t-butyl group at the non-prime side. The second most abundant metabolite, M2, was also a mono-oxidation product, which has not yet been definitively identified. Metabolites, M3 and M4, were structural isomers, which were apparently formed by oxidative carbamate hydrolysis. The structure of M5 comprises the non-prime side of atazanavir which contains a pyridinyl-benzyl group. Metabolite M6a was formed by the cleavage of the pyridinyl-benzyl side chain, as evidenced by the formation of the corresponding metabolic product, the pyridinyl-benzoic acid (M6b). Mono-oxidation also occurred on the pyridinyl-benzyl group to produce the low abundance metabolite M8. Oxidation of the terminal methyl groups produced M9 and M10, respectively, which have low chemical stability. Trace-level metabolites of di-oxidations, M11 and M12, were also detected, but the complexity of the molecule precluded identification of the second oxidation site. To our knowledge, metabolites M6b and M8 have not been reported.

Atazanavir pharmacokinetics, efficacy and safety in pregnancy: a systematic review

BACKGROUND

For some antiretroviral therapies, drug concentrations are reduced during pregnancy, potentially compromising effective virological suppression.

METHODS

Data on atazanavir boosted with ritonavir in pregnancy are reviewed.

RESULTS

With standard atazanavir/ritonavir 300/100 mg once-daily dosing: atazanavir area-under-the-concentration-time curves were reduced during pregnancy in most studies, but overall interpretation differed according to the data used for comparison; atazanavir concentration 24 h post-dose was maintained >150 ng/ml in 97.6% of women; no instance of mother-to-child transmission occurred in treatment-adherent mothers; and infant hyperbilirubinaemia was not elevated beyond levels expected in the neonatal period.

CONCLUSIONS

With concurrent medications that reduce atazanavir drug concentrations, optimal therapy during pregnancy may require once-daily atazanavir/ritonavir 400/100 mg; however, using this dose during the third trimester doubled maternal grade 3-4 hyperbilirubinaemia rates.