Drug-induced liver injury associated with the use of nonnucleoside reverse-transcriptase inhibitors

Time to develop adverse drug reactions and associated factors among children HIV positive patients on antiretroviral treatment in North West Amhara Specialized Hospitals: Retrospective cohort study, 2022

Introduction

Adverse drug reactions (ADRs) are harmful and unintended reactions to medicines given at standard doses through a proper route of administration for the purpose of prophylaxis, diagnosis, or treatment.

Objective

The objective of this research paper was to assess median time to development of ADRs and associated factors among children HIV positive patients on antiretroviral treatment (ART) in North West Amhara Specialized Hospitals.

Methods

The adverse drug effect survival time was estimated using the Kaplan-Meier survival method and log-rank test curves was applied for analyze "time-to-event" data. Cox regression model was used to identify the associated factors. Adjusted hazard ratios with their respective 95% confidence intervals (CIs) were estimated and a value of p less than 0.05 was used to declare the presence of a significant association.

Result

The overall incidence of ADRs was 0.67 (95% CI: 3.74-4.44) per 10,000 person-year observation, with a median of 57 months. Adults are presenting with opportunistic Infections (OIs) experiences, baseline CD4 < 200 cells/µL counts, 1e, tenofovir disoproxil fumarate-lamivudine-efavirenz ART regimen, bedridden baseline functional status, World Health Organization (WHO) clinical stage II and III were notably associated with the incidence of ADRs development.

Conclusion

ADRs were uncommon in this study. predictors, such as OIs experiences, a low CD4 count, ART regimen, an advanced WHO stage, and bedridden functional status were significantly associated with ADRs.

Analytical and Omics-Based Advances in the Study of Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a significant clinical issue, affecting 1-1.5 million patients annually, and remains a major challenge during drug development-toxicity and safety concerns are the second-highest reason for drug candidate failure. The future prevalence of DILI can be minimized by developing a greater understanding of the biological mechanisms behind DILI. Both qualitative and quantitative analytical techniques are vital to characterizing and investigating DILI. In vitro assays are capable of characterizing specific aspects of a drug's hepatotoxic nature and multiplexed assays are capable of characterizing and scoring a drug's association with DILI. However, an even deeper insight into the perturbations to biological pathways involved in the mechanisms of DILI can be gained through the use of omics-based analytical techniques: genomics, transcriptomics, proteomics, and metabolomics. These omics analytical techniques can offer qualitative and quantitative insight into genetic susceptibilities to DILI, the impact of drug treatment on gene expression, and the effect on protein and metabolite abundance. This review will discuss the analytical techniques that can be applied to characterize and investigate the biological mechanisms of DILI and potential predictive biomarkers.

NNRTI and Liver Damage: Evidence of Their Association and the Mechanisms Involved

Due to the improved effectiveness and safety of combined antiretroviral therapy, human immunodeficiency virus (HIV) infection has become a manageable, chronic condition rather than a mortal disease. However, HIV patients are at increased risk of experiencing non-AIDS-defining illnesses, with liver-related injury standing out as one of the leading causes of death among these patients. In addition to more HIV-specific processes, such as antiretroviral drug-related toxicity and direct injury to the liver by the virus itself, its pathogenesis is related to conditions that are also common in the general population, such as alcoholic and non-alcoholic fatty liver disease, viral hepatitis, and ageing. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are essential components of combined anti-HIV treatment due to their unique antiviral activity, high specificity, and acceptable toxicity. While first-generation NNRTIs (nevirapine and efavirenz) have been related largely to liver toxicity, those belonging to the second generation (etravirine, rilpivirine and doravirine) seem to be generally safe for the liver. Indeed, there is preclinical evidence of rilpivirine being hepatoprotective in different models of liver injury, independently of the presence of HIV. The present study aims to review the mechanisms by which currently available anti-HIV drugs belonging to the NNRTI family may participate in the development of liver disease.

Dolutegravir-Based Regimen for Maintenance of Viral Suppression in People Living with HIV: 48-Week Results in Real-Life Setting

To evaluate the efficacy, safety, and tolerability of switching to a dolutegravir (DTG)-based regimen in a cohort of virological suppressed HIV-infected patients who have previously been treated with different antiretroviral combination. The dynamics of total HIV-DNA and levels of high-sensitivity c-reactive protein, interleukin-6, soluble-CD14, and D-Dimer were also analyzed. Ninety-six individuals who switched to a DTG-containing regimen were followed up for 48 weeks. HIV RNA, CD4⁺ T cell count, weight, and levels of laboratory parameters were recorded at baseline, after 24 and 48 weeks of treatment for all study participants. In a subgroup of patients, HIV DNA and inflammation/coagulation marker levels were also analyzed until week 24. Ninety-three out of 96 patients maintained virological suppression, including patients who switched to dual-therapy from triple-drug combination. Eighteen out of 96 patients had residual viremia at baseline, of which 13 reached the maximal viral suppression at W48. Serum creatinine levels showed a significant increase at weeks 24 and 48. A progressive reduction of total cholesterol was observed from week 24 and up to week 48. No variation in body mass index was detected. HIV DNA, inflammation, and coagulation marker levels did not significantly change during follow-up. Switching to a DTG-based regimen may be a key option for achieving and maintaining maximal virological suppression, even in patients showing residual viremia at baseline. Furthermore, the improvement in blood lipid profile and the overall tolerability observed in this study strongly support the use of these regimens in the aging HIV population.

Cambios en los valores de las pruebas de función hepática en pacientes con VIH en Tratamiento Antirretroviral de Gran Alcance (TARGA). Estudio longitudinal en Lima, Perú

Introducción. Para prevenir el desarrollo de enfermedad hepática crónica en pacientes con VIH durante la Terapia Antirretroviral de Gran Actividad (TARGA) se deben estimar y monitorear cambios en el perfil hepático. Objetivo. Determinar la variación de las concentraciones del perfil hepático en pacientes con VIH durante la TARGA. Materiales y métodos. Estudio retrospectivo longitudinal realizado en 100 pacientes con VIH atendidos en el Hospital Nacional Hipólito Unanue, Lima, Perú, entre 2015 y 2017. Se incluyeron pacientes en todos los estadios de infección clínica que estuvieran recibiendo TARGA y en los que se contara con resultados del perfil hepático para alanina aminotransferasa (ALT), aspartato aminotransferasa (AST), fosfatasa alcalina (FA), Gammaglutamiltranspeptidasa (GGT), y proteínas totales (PT). Se realizaron tres análisis de control de la función hepática (cada 3 meses) durante la TARGA y los participantes se agruparon en niveles normales y elevados para todos los marcadores hepáticos. Las diferencias entre las muestras analizadas fueron determinadas mediante la prueba t de Student para muestras relacionadas, con un intervalo de confianza de 95% y un nivel de significancia de p<0.05. Resultados. La edad promedio fue de 33±9.56 años y el 67% fueron varones. Los valores séricos promedio de AST, ALT, y FA disminuyeron entre la primera y la tercera medición (p=0.021, p=0.076, y p=0.002, respectivamente). No se observaron diferencias significativas en los niveles de GGT y PT entre las tres mediciones, ni entre los pacientes con valores normales y elevados para AST, ALT, FA y PT, pero sí para GGT (p=0.010). Conclusiones. Se observaron variaciones en los niveles de los marcadores hepáticos de todos los participantes, con una tendencia a la reducción en AST, ALT y FA entre las etapas iniciales y finales de la terapia, lo que implica que la TARGA podría ejercer un rol en el daño tisular hepático.

Hepatotoxicity of Contemporary Antiretroviral Drugs: A Review and Evaluation of Published Clinical Data

Contemporary antiretroviral agents afford enhanced potency and safety for patients living with HIV. Newer antiretroviral drugs are often better tolerated than those initially approved in the early stages of the HIV epidemic. While the safety profile has improved, adverse drug reactions still occur. We have segregated the antiretroviral agents used in contemporary practice into class groupings based on their mechanism of antiviral activity (non-nucleoside reverse transcriptase inhibitors, nucleoside reverse transcriptase inhibitors, integrase inhibitors, protease inhibitors, and entry inhibitors) while providing a review and discussion of the hepatoxicity seen in the most relevant clinical literature published to date. Clinical literature for individual agents is discussed and agent comparisons afforded within each group in tabular format. Our review will provide a summative overview of the incidence and medications associated with hepatic adverse reactions linked to the use of contemporary antiretroviral drugs.

Clinical and genetic factors associated with increased risk of severe liver toxicity in a monocentric cohort of HIV positive patients receiving nevirapine-based antiretroviral therapy

Background

Nevirapine has been used as antiretroviral agent since early ‘90. Although nevirapine is not currently recommended in initial anti-HIV regimens, its use remains consistent in a certain number of HIV-1-positive subjects. Thus, our aim was to determine clinical and genetic factors involved in the development of severe nevirapine induced liver toxicity.

Methods

We retrospectively analyzed all HIV positive patients who were followed at the Infectious Diseases Unit, DIBIC Luigi Sacco, University of Milan from May 2011 to December 2015. All patients treated with nevirapine who underwent a genotyping for the functional variants mapping into ABCB1, CYP2B6, CYP3A4 and CYP3A5 genes were included in the analysis. Severe hepatotoxicity was defined as ACTG grade 3–4 AST/ALT increase during the first three months of nevirapine treatment. The causality assessment between NVP exposure and drug-induced liver injury was performed by using the updated Roussel Uclaf Causality Assessment Methods. Hardy Weinberg equilibrium was tested by χ² test. A multivariable logistic regression model was constructed using a backward elimination method.

Results

Three hundred and sixty-two patients were included in the analysis, of which 8 (2.2%) experienced a severe liver toxicity. We observed no differences between patients with and without liver toxicity as regards gender, ethnicity, age and immune-virological status. A higher prevalence of HCV coinfection (75.0% vs 30.2%; p = .0013) and higher baseline AST (58 IU/L vs 26 IU/L; p = 0.041) and ALT (82 IU/L vs 27 IU/L; p = 0.047) median levels were observed in patients with liver toxicity vs those without toxicity. The genotypes CT/TT at ABCB1 rs1045642 single nucleotide polymorphism (SNP), showed a protective effect for liver toxicity when compared with genotype CC (OR = 0.18, 95%CI 0.04–0.76; p = 0.020) in univariate analysis. In the multivariate model, HCV coinfection was independently associated with higher risk of developing liver toxicity (aOR = 8.00, 95%CI 1.27–50.29; p = 0.027), whereas ABCB1 rs1045642 CT/TT genotypes (aOR = 0.10, 95%CI 0.02–0.47; p = 0.004) was associated with a lower risk.

Conclusions

According to our findings HCV coinfection and ABCB1 rs1045642 SNP represent independent determinants of severe liver toxicity related to nevirapine. This genetic evaluation could be included as toxicity assessment in HIV-1-positive subjects treated with nevirapine.

Interaction of Nevirapine with the Peptide Binding Groove of HLA-DRB1*01:01 and Its Effect on the Conformation of HLA-Peptide Complex

Human leukocyte antigen (HLA)-DRB1*01:01 has been shown to be involved in nevirapine-induced hepatic hypersensitivity reactions. In the present study, in silico docking simulations and molecular dynamics simulations were performed to predict the interaction mode of nevirapine with the peptide binding groove of HLA-DRB1*01:01 and its possible effect on the position and orientation of the ligand peptide derived from hemagglutinin (HA). In silico analyses suggested that nevirapine interacts with HLA-DRB1*01:01 around the P4 pocket within the peptide binding groove and the HA peptide stably binds on top of nevirapine at the groove. The analyses also showed that binding of nevirapine at the groove will significantly change the inter-helical distances of the groove. An in vitro competitive assay showed that nevirapine (1000 μM) increases the binding of the HA peptide to HLA-DRB1*01:01 in an allele-specific manner. These results indicate that nevirapine might interact directly with the P4 pocket and modifies its structure, which could change the orientation of loaded peptides and the conformation of HLA-DRB1*01:01; these changes could be distinctively recognized by T-cell receptors. Through this molecular mechanism, nevirapine might stimulate the immune system, resulting in hepatic hypersensitivity reactions.

HBV, HCV, and HBV/HCV co-infection among HIV-positive patients in Hunan province, China: Regimen selection, hepatotoxicity, and antiretroviral therapy outcome

Co-infection with hepatitis B (HBV) and C (HCV) is common among people living with HIV (PLHIV). This study investigates the impacts of hepatitis co-infection on antiretroviral therapy (ART) outcomes and hepatotoxicity in PLHIV. The cohort study included 1984 PLHIV. Hepatotoxicity was defined by elevated alanine aminotransferase (ALT) levels. ART outcomes were measured by CD4 cell counts, viral load, and mortality rate in patients. Among 1984 PLHIV, 184 (9.3%) were co-infected with HBV and 198 (10.0%) with HCV and 54 (2.7%) were co-infected with HBV and HCV. Of these patients, 156 (7.9%) had ALT elevation ≥ grade 1 at baseline. During the course of ART, the mortality rate and its adjusted hazard ratio (AHR) in PLHIV who were co-infected with HCV (2.6/100 person-years [py], AHR = 2.3, 95%CI 1.1-4.7) was higher than for patients with mono-infected HIV, as it was for those with an elevated ALT (4.4/100 py, AHR = 3.8, [1.7-8.2]) at baseline compared to those with normal ALT. After 6-12 months of ART, the incidence of hepatotoxicity among all the patients was 3.7/100 py. The risk of hepatotoxicity was higher in HCV co-infected (18.6/100 py, adjusted odds ratio [AOR] = 12.4, [8.1-18.2]) than HIV mono-infected patients, and for all regimens (nevirapine: 30.0/100 py, 34.2, 7.3-47.9; zidovudine/stavudine: 24.7/100 py, 22.1, 7.1-25.5; efavirenz: 14.5/100 py, 9.4, 3.5-19.2; lopinavir/ritonavir: 40.1/100 py, 52.2, 9.5-88.2) except tenofovir (4.3/100 py, 4.9, 0.8-9.5). Patients with HBV/HCV co-infected had high hepatotoxicity (10.0/100 py, 6.3, 1.2-23.3) over the same period. Patients with HCV co-infection and HBV/HCV co-infection demonstrated higher hepatotoxicity rate compared with HIV mono-infected patients in China.

Prevalence and Clinical Spectrum of Liver Disease in Nepalese HIV-Sero-Positive Patients Undergoing Antiretroviral Therapy: A Cross-Sectional Hospital Based Study

Introduction

Liver enzyme abnormalities are common in HIV patients, and the prevalence varies across the nations. In Nepal, however, prevalence of liver enzyme disorder and the spectrum of these populations are lacking.

Objective

The present study sheds light on prevalence and clinical spectrum of liver disease in Nepalese HIV-sero-positive patients.

Methods

This cross-sectional study was conducted at OPD/ART, Clinic of Bir Hospital, NAMS. One hundred and forty-four HIV positive patients were enrolled consecutively and their clinical profiles of liver injury were investigated.

Results

Of 144 recruited patients, liver enzyme injury was observed in 82 (56.9%). Majority 61 (42.4%) of these cases had hepatocellular type of liver injury. Opportunistic infections were reported in 18 cases, with 9 (6.2%) TB and 8 (5.6%) HCV. Test for significance of liver injury confirmed the absence of any tendency towards an association with coinfection, CD4 cells, ART regimen, and alcohol consumption (P > 0.05). However, gender significantly linked with liver injury as well as the pattern of liver injury (P < 0.05).

Conclusion

The study revealed high rate of liver injury in a substantial proportion of HIV individuals, stressing that a regular clinic follow-up is necessary for the HIV individuals who are undergoing ART.

Human Immunodeficiency Virus Infection, Antiretroviral Therapy, and Liver Pathology

The improvement in antiretroviral therapy has significantly impacted the lives of people living with human immunodeficiency virus (HIV). In high-income countries, HIV deaths are predominated by liver disease consequent to viral hepatitis coinfection, alcohol, and nonalcoholic fatty liver disease. Published liver pathology findings have shifted from being predominated by opportunistic infections to the metabolic effects of HIV and antiretroviral therapy as well as drug-induced liver injuries. Differences remain between high-income and low-income countries, where opportunistic infections and immune reconstitution syndromes, dominate findings.

Multicenter study of skin rashes and hepatotoxicity in antiretroviral-naïve HIV-positive patients receiving non-nucleoside reverse-transcriptase inhibitor plus nucleoside reverse-transcriptase inhibitors in Taiwan

OBJECTIVES

Two nucleos(t)ide reverse-transcriptase inhibitors (NRTIs) plus 1 non-NRTI (nNRTI) remain the preferred or alternative combination antiretroviral therapy (cART) for antiretroviral-naive HIV-positive patients in Taiwan. The three most commonly used nNRTIs are nevirapine (NVP), efavirenz (EFV) and rilpivirine (RPV). This study aimed to determine the incidences of hepatotoxicity and skin rashes within 4 weeks of initiation of cART containing 1 nNRTI plus 2 NRTIs.

METHODS

Between June, 2012 and November, 2015, all antiretroviral-naive HIV-positive adult patients initiating nNRTI-containing cART at 8 designated hospitals for HIV care were included in this retrospective observational study. According to the national HIV treatment guidelines, patients were assessed at baseline, 2 and 4 weeks of cART initiation, and subsequently every 8 to 12 weeks. Plasma HIV RNA load, CD4 cell count and aminotransferases were determined. The toxicity grading scale of the Division of AIDS (DAIDS) 2014 was used for reporting clinical and laboratory adverse events.

RESULTS

During the 3.5-year study period, 2,341 patients initiated nNRTI-containing cART: NVP in 629 patients, EFV 1,363 patients, and RPV 349 patients. Rash of any grade occurred in 14.1% (n = 331) of the patients. In multiple logistic regression analysis, baseline CD4 cell counts (per 100-cell/μl increase, adjusted odds ratio [AOR], 1.125; 95% confidence interval [95% CI], 1.031-1.228) and use of NVP (AOR, 2.443; 95% CI, 1.816-3.286) (compared with efavirenz) were independently associated with the development of skin rashes. Among the 1,455 patients (62.2%) with aminotransferase data both at baseline and week 4, 72 (4.9%) developed grade 2 or greater hepatotoxicity. In multiple logistic regression analysis, presence of antibody for hepatitis C virus (HCV) (AOR, 2.865; 95% CI, 1.439-5.704) or hepatitis B surface antigen (AOR, 2.397; 95% CI, 1.150-4.997), and development of skin rashes (AOR, 2.811; 95% CI, 1.051-7.521) were independently associated with the development of hepatotoxicity.

CONCLUSIONS

The baseline CD4 cell counts and use of NVP were associated with increased risk of skin rashes, while hepatotoxicity was independently associated with HCV or hepatitis B virus coinfection, and development of skin rashes in antiretroviral-naïve HIV-positive Taiwanese patients within 4 weeks of initiation of nNRTI-containing regimens.

A cross-sectional study of liver function tests in HIV-infected persons in Western India

BACKGROUND

Derangement of liver function tests (LFTs) is common in people living with human immunodeficiency virus/acquired immune deficiency syndrome (PLHA). The cause is multifactorial. Drug-induced liver injury (DILI) is the commonest cause and others being alcohol abuse and concomitant viral hepatitis. The aim of the research was to study the prevalence of LFT abnormalities in PLHA.

METHODS

The study was carried out in a tertiary care hospital. Evaluation included a detailed history, thorough clinical examination and investigations including a haemogram, serum biochemistry, serology for hepatitis, and CD4 cell count.

RESULTS

A total of 247 patients were evaluated. Of these, 212 (85.82%) were on antiretroviral therapy (ART), 111 (44.93%) were on anti-tubercular therapy (ATT), and 94 (38.05%) were on concurrent ATT-ART. Abnormal LFTs were seen in 128/247 (51.82%) PLHA. In the majority (88.28%), the LFT abnormalities were mild. LFT abnormalities were seen in 109/212 (51.4%) patients on ART, in 56/111 (50.5%) patients on ATT, 46/94 (48.93%) patients on concurrent ART-ATT. There was no difference in LFT abnormalities among the three groups nor was there any significant association with alcohol consumption. There was a statistically significant co-relation between albumin/globulin ratio and CD4 count (p = 0.0002). Counter-intuitively, LFT abnormalities were commoner in patients not receiving nevirapine (p = 0.043), but severe abnormalities (grade III/grade IV) were commoner in those receiving nevirapine (p = 0.005) and in those on concurrent ART-ATT (p = 0.008).

CONCLUSION

LFT abnormalities in PLHA are common; but usually mild. There is a strong association between severe abnormalities and nevirapine-based therapy (p = 0.02) and concurrent ATT-ART (p = 0.008).

Antitubercular therapy induced liver function tests abnormalities in human immunodeficiency virus infected individuals

BACKGROUND

Both antitubercular therapy (ATT) and antiretroviral therapy (ART) can cause drug induced liver injury (DILI) in tuberculosis (TB) and human immunodeficiency virus (HIV) coinfection. The aim of this research was to study ATT-induced liver function test (LFT) abnormalities in HIV-infected patients.

METHODS

HIV-infected patients diagnosed with TB were evaluated with baseline LFT and CD4 counts. ATT regimen was modified if baseline LFT was significantly abnormal. Patients on protease inhibitors were given rifabutin instead of rifampicin. In patients on nevirapine-based ART, efavirenz was substituted for nevirapine. In ART-naive patients, the timing of introduction of ART was according to CD4 cell counts. LFT were repeated fortnightly or as clinically indicated for 10 weeks.

RESULTS

We studied 100 patients with HIV ([M - 67, F - 23], mean age: 40.05 ± 10.75 years, mean CD4 cell count: 239.157 ± 228.49 cells/dL). Sixty-one patients were on ART prior to diagnosis of TB. Baseline LFT abnormalities (n = 40) were similar in ART and non-ART group (28/61 vs 12/39, p = 0.13). After starting ATT, derangement of LFT was observed in majority of patients (99/100). However, liver sparing ATT was required only in 15 patients. Bilirubin >2.5 mg/dL was seen only in 9 patients. Significant rise in transaminases was commoner in patients on concurrent ART and ATT (p = 0.044) and with baseline LFT abnormalities (p = 0.00016). There was no case of acute liver failure or mortality.

CONCLUSION

Mild LFT abnormalities are common in HIV-infected individuals on ATT. Concomitant use of ATT and ART and baseline LFT abnormalities increase the risk of significant DILI. However, with closer follow-up, serious liver injury can be prevented.

The CYP2B6 G516T polymorphism influences CD4+ T-cell counts in HIV-positive patients receiving antiretroviral therapy in an ethnically diverse region of the Amazon

OBJECTIVES

Cytochrome P450 (CYP) enzyme polymorphisms seem to significantly influence the variability of the responses to certain antiretroviral drugs and their toxicity levels. The objective of this study was to evaluate the influence of the CYP2B6 G516T polymorphism on hepatic, renal, immunological, and viral marker changes in HIV-1-positive patients receiving treatment in an ethnically diverse region of the Amazon.

METHODS

CYP2B6 G516T genotyping was performed by real-time PCR (RT-PCR) in samples from 185 patients. Urea, creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), CD4⁺/CD8⁺ T-cell counts, and HIV-1 plasma viral load were measured.

RESULTS

The polymorphic CYP2B6 G516T allele frequency was 0.36, which is different from the frequencies in other ethnic groups. The polymorphic genotype was associated with changes in the urea and ALT levels, although the median values were within the normal range. The TT genotype was also associated with significantly lower CD4⁺ T-cell counts in patients using efavirenz.

CONCLUSIONS

The CYP2B6 G516T polymorphism seems to affect the response to efavirenz treatment by reducing CD4⁺ T-cell counts in patients with a high degree of miscegenation who use this antiretroviral agent.

Use of antiretroviral therapy and risk of end-stage liver disease and hepatocellular carcinoma in HIV-positive persons

OBJECTIVES

Although several antiretroviral drugs, including the d-drugs stavudine (d4T) and didanosine (ddI), may cause biomarker-defined hepatotoxicity, their association with clinically defined end-stage liver disease (ESLD) and hepatocellular carcinoma (HCC) remains unknown.

DESIGN

Prospective cohort study.

METHODS

Data collection on adverse events of anti-HIV drugs study (D:A:D) participants were followed until the first of ESLD (variceal bleeding, hepatic encephalopathy, hepatorenal syndrome or liver transplantation), HCC (histology or α-fetoprotein along with imaging), death, 6 months after last visit or 1 February 2014. Associations between ESLD/HCC and cumulative use of individual antiretrovirals were investigated using Poisson regression adjusting for potential confounders.

RESULTS

During a median follow-up of 8.4 years, 319 ESLD/HCC cases occurred [incidence 1.01/1000 person-years (95% confidence interval 0.90-1.12)] with a 1-year mortality rate of 62.6%. After adjustment, cumulative (per 5 years) exposure to d4T [relative rate 1.46 (95% confidence interval 1.20-1.77)], ddI [1.32 (1.07-1.63)], tenofovir [TDF, 1.46 (1.11-1.93)] and (fos)amprenavir [APV; 1.47 (1.01-2.15)] was associated with increased ESLD/HCC rates. Longer exposure to emtricitabine [0.51 (0.32-0.83)] and nevirapine [0.76 (0.58-0.98)] were associated with lower ESLD/HCC rates. The ddI/d4T-associated increased ESLD/HCC rate only started to decline 6 years after cessation.

CONCLUSION

Cumulative use of d4T, ddI, TDF and APV were independently associated with increased ESLD/HCC rates, and intensified monitoring of liver function should hence be considered among all individuals exposed for longer time periods. The use of d-drugs should furthermore be avoided, where there are alternatives available, and focus should be put on those with longer-term d-drugs exposure who remain at increased ESLD/HCC risk. The unexpected, and viral hepatitis-independent, TDF association calls for further investigations.

Adverse Effects Associated With Antiretroviral Therapy and Potential Management Strategies

A variety of adverse drug reactions (ADRs) affecting many organ systems may be observed with antiretroviral therapy (ARV), and they can be differentiated into short- and long- term effects, class effects, or individual drug effects. Commonly seen ADRs include dermatological reactions, associated with nonnucleoside reverse transcriptase inhibitors (NNRTIs) and some protease inhibitors (PIs), and gastrointestinal problems, a major side effect of PIs and of some nucleoside reverse transcriptase inhibitors (NRTIs). Metabolic complications are frequently reported in HIV-infected patients on ARV and often coexist. Lipodystrophy, hyperinsulinemia/hyperglycemia, and bone disorders (osteoporosis, osteonecrosis) are mainly associated with PIs, while lactic acidemia/acidosis are primarily a problem of NRTIs. Hyperlipidemia may be caused by almost all PIs, few NRTIs, and NNRTIs. All antiretroviral drug classes may cause both asymptomatic and symptomatic hepatotoxicity, although nevirapine is the agent most implicated in hepatic events. More drug-specific ADRs include nephrotoxicity (indinavir and tenofovir), central nervous system problems (efavirenz), hematological disturbances (zidovudine), and hypersensitivity reactions (abacavir). Anticipation of ADRs may influence a patient’s decision to delay ARV or to choose specific and potentially less active agents. Occurrence of ADRs may significantly impact a patient’s quality of life and drug adherence. Pharmacists counseling HIV-infected patients should be aware of common ADRs with ARV and potential management strategies.

Effects of CYP2B6 and CYP1A2 Genetic Variation on Nevirapine Plasma Concentration and Pharmacodynamics as Measured by CD4 Cell Count in Zimbabwean HIV-Infected Patients

The extremely high prevalence of HIV/AIDS in sub-Saharan Africa and limitations of current antiretroviral medicines demand new tools to optimize therapy such as pharmacogenomics for person-to-person variations. African populations exhibit greater genetic diversity than other world populations, thus making it difficult to extrapolate findings from one population to another. Nevirapine, an antiretroviral medicine, displays large plasma concentration variability which adversely impacts therapeutic virological response. This study, therefore, aimed to identify sources of variability in nevirapine pharmacokinetics and pharmacodynamics, focusing on genetic variation in CYP2B6 and CYP1A2. Using a cross-sectional study design, 118 HIV-infected adult Zimbabwean patients on nevirapine-containing highly active antiretroviral therapy (HAART) were characterized for three key functional single nucleotide polymorphisms (SNPs), CYP2B6 c.516G>T (rs3745274), CYP2B6 c.983T>C (rs28399499), and CYP1A2 g.-163C>A (rs762551). We investigated whether genotypes at these loci were associated with nevirapine plasma concentration, a therapeutic biomarker, and CD4 cell count, a biomarker of disease progression. CYP2B6 and CYP1A2 were chosen as the candidate genes based on reports in literature, as well as their prominence in the metabolism of efavirenz, a drug in the same class with nevirapine. Nevirapine plasma concentration was determined using LC-MS/MS. The mean nevirapine concentration for CYP2B6 c.516T/T genotype differed significantly from that of 516G/G (p < 0.001) and 516G/T (p < 0.01) genotypes, respectively. There were also significant differences in mean nevirapine concentration between CYP2B6 c.983T > C genotypes (p = 0.04). Importantly, the CYP1A2 g.-163C>A SNP was significantly associated with the pharmacodynamics endpoint, the CD4 cell count (p = 0.012). Variant allele frequencies for the three SNPs observed in this Zimbabwean group were similar to other African population groups but different to observations among Caucasian and Asian populations. We conclude that CYP2B6 c.516G>T and CYP2B6 c.983T>C could be important sources of nevirapine pharmacokinetic variability that could be considered for dosage optimization, while CYP1A2 g.-163C>A seems to be associated with HIV disease progression. These inter- and intra-population pharmacokinetic and pharmacodynamics differences suggest that a single prescribed dosage may not be appropriate for the treatment of disease. Further research into a personalized nevirapine regimen is required.

Identification of a novel and severe pattern of efavirenz drug-induced liver injury in South Africa

Efavirenz now forms part of many antiretroviral regimens in low and middle-income countries. Efavirenz-related drug-induced liver injury is not well characterized but is thought to occur less frequently than with nevirapine. We describe our observation of three defined clinicopathological patterns of injury, one of which, submassive necrosis, is associated with significant morbidity and mortality. A high baseline CD4, younger age and possibly female gender, predicts for the injury.

Pharmacoepidemiology of antiretroviral drugs in a teaching hospital in Lagos, Nigeria

OBJECTIVE

Prescribing, adherence, and adverse drug events to HAART in a large antiretroviral programme in Lagos was evaluated.

DESIGN

A retrospective 5 year open cohort study.

SETTING

The AIDS Prevention Initiative in Nigeria (APIN) clinic at LUTH is one of the United States Presidential Emergency Plan for AIDS Relief (PEP-FAR) funded centers for HIV relief program in Nigeria Participants The case files of 390 patients on HAART and attending the APIN clinic were reviewed sequel to random selection.

MAIN OUTCOME MEASURES

Demographics of the patients and pattern of antiretroviral (ARV) combination drugs prescribed were extracted from their case files. The details of the adverse drug events (ADEs) were extracted from drug toxicity forms regularly filled for each patient. A Chi-square test with Yates correction was used to determine the association between adherence and therapeutic outcome.

RESULTS

A total of 2944 prescriptions were assessed. Zidovudine + lamivudine + nevirapine (35.87%) and stavudine + lamivudine + nevirapine (35.63%) were the most frequently prescribed combinations. Over 2000 ADEs were reported with cough (13.3%), fever (8.75%) and skin rashes (8.01%) being the most frequently reported. Drug adherence was associated with good therapeutic outcome (χ(2) = 115.60, p<0.0001).

CONCLUSIONS

Zidovudine + lamivudine + nevirapine was the most frequently prescribed ARV combination. Cough was the most frequently reported ADE. Interventions aimed at rational prescribing of ARV drugs and improving adherence to antiretroviral drugs is essential for good therapeutic outcome in the treatment of HIV infection.

Progression of Liver Fibrosis and Modern Combination Antiretroviral Therapy Regimens in HIV-Hepatitis C-Coinfected Persons

In human immunodeficiency virus–hepatitis C-coinfected, both protease inhibitor- and nonnucleoside reverse transcriptase inhibitor-based regimens were associated with progression of liver fibrosis over time when paired with a backbone of abacavir/lamivudine but not tenofovir/emtricitabine.

Background. Liver diseases progress faster in human immunodeficiency virus (HIV)–hepatitis C virus (HCV)-coinfected persons than HIV-monoinfected persons. The aim of this study was to compare rates of liver fibrosis progression (measured by the aspartate-to-platelet ratio index [APRI]) among HIV-HCV–coinfected users of modern protease inhibitor (PI)- and nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens with a backbone of tenofovir/emtricitabine (TDF/FTC) or abacavir/lamivudine (ABC/3TC).

Methods. Data from a Canadian multicenter cohort study were analyzed, including 315 HCV polymerase chain reaction–positive persons who initiated antiretroviral therapy with a PI or NNRTI and a backbone containing either TDF/FTC or ABC/3TC. Multivariate linear regression analyses with generalized estimating equations were performed after propensity score matching to balance covariates across classes of anchor agent.

Results. A backbone of TDF/FTC was received by 67% of PI users and 69% of NNRTI users. Both PI and NNRTI use was associated with increases in APRI over time when paired with a backbone of ABC/3TC: 16% per 5 years (95% confidence interval [CI], 4%, 29%) and 11% per 5 years (95% CI, 2%, 20%), respectively. With TDF/FTC use, no clear association was found among PI users (8% per 5 years, 95% CI, −3%, 19%) or NNRTI users (3% per 5 years, 95% CI, −7%, 12%).

Conclusions. Liver fibrosis progression was more influenced by the backbone than by the class of anchor agent in HIV-HCV–coinfected persons. Only ABC/3TC-containing regimens were associated with an increase of APRI score over time, regardless of the class of anchor agent used.

Pharmacogenetics as a tool to tailor antiretroviral therapy: A review

Highly active antiretroviral therapy (HAART) has substantially changed human immunodeficiency virus (HIV) infection from an inexorably fatal condition into a chronic disease with a longer life expectancy. This means that HIV patients should receive antiretroviral drugs lifelong, and the problems concerning with a chronic treatment (tolerability, side effects, adherence to treatment) have now become dominant. In this context, strategies for the treatment personalization have taken a central role in optimizing the therapeutic response and prevention of adverse drug reactions. In this setting, the study of pharmacogenetics features could be a very useful tool in clinical practice; moreover, nowadays the study of genetic profiles allows optimizations in the therapeutic management of People Living With HIV (PLWH) through the use of test introduced into clinical practice and approved by international guidelines for the adverse effects prevention such as the genetic test HLA-B*5701 to detect hypersensitivity to Abacavir. For other tests further studies are needed: CYP2B6 516 G > T testing may be able to identify patients at higher risk of Central Nervous System side effects following standard dosing of Efavirenz, UGT1A1*28 testing before initiation of antiretroviral therapy containing Atazanavir may aid in identifying individuals at risk of hyperbilirubinaemia. Pharmacogenetics represents a ​​research area with great growth potential which may be useful to guide the rational use of antiretrovirals.

Liver safety assessment in special populations (hepatitis B, C, and oncology trials)

The FDA guidance for industry in the premarketing clinical evaluation of drug-induced liver injury (DILI) is the most specific regulatory guidance currently available and has been useful in setting standards for the great majority of clinical indications involving subjects with a low risk of liver disorders. However, liver safety assessment faces challenges in populations with underlying liver disease, such as viral hepatitis or metastatic cancer. This is an important issue because there are currently many promising anti-viral and oncologic therapies in clinical development, with a trend toward oral therapies with reduced side effects. Without clearer guidelines, questions regarding liver safety may become a major factor in regulatory approval and ultimately physician uptake of the new treatments. The lack of consensus in defining stopping rules based on serum alanine aminotransferase (ALT) levels underscores the need for precompetitive data sharing to improve our understanding of DILI in these populations and to allow evidence-based rather than empirical definition of stopping rules. A workshop was convened to discuss best practices for the assessment of drug-induced liver injury (DILI) in clinical trials.

A clinicopathological cohort study of liver pathology in 301 patients with human immunodeficiency virus/acquired immune deficiency syndrome

Liver disease complicates human immunodeficiency virus (HIV)/acquired immune deficiency syndrome; however, liver pathology data are limited, particularly from high HIV prevalence countries. We investigated the spectrum and clinicopathological correlates of liver pathology in a high HIV burden setting. In a single-center study, all HIV/acquired immune deficiency syndrome patients with complete clinical and demographic data who underwent liver biopsy were analyzed and clinicopathologically assessed by hepatologists and one of two experienced liver pathologists. We evaluated 301 patients, with a median age of 34 (interquartile range 29-40) years. Women (n = 143) were younger than men (n = 158), with a median age of 33 (interquartile range 28-37) versus 35 (interquartile range 31-41) years, P = 0.001. The majority, 76.1%, were black African. Median CD4 at time of biopsy was 127 (52-260) cells/mm(3) . Drug-induced liver injury was the predominant finding (42.2%), followed by granulomatous inflammation (29%), steatosis/steatohepatitis (19.3%), hepatitis B (19%), and hepatitis C coinfection (3.3%), with more than one pathology in 16.2%. With granulomatous inflammation, 52% met the criteria for tuberculosis immune reconstitution syndrome. By univariate analysis, cotrimoxazole and antiretroviral therapy conferred risk for drug injury (odds ratio [OR] = 2.78 [1.72-4.48], P < 0.001; OR = 1.69 [1.06-2.68], P = 0.027). In multivariate analysis, cotrimoxazole was associated with a cholestatic or ductopenic injury (OR = 7.05 [2.50-19.89], P < 0.001; OR = 17.6 [3.26-95.3], P < 0.0001); efavirenz was associated with nonspecific hepatitis or submassive necrosis (OR = 4.3 [1.92-9.83], P < 0.001; OR = 10.46 [2.7-40.5], P < 0.001). Cholestatic injury was associated with female gender and a CD4 of >200 cells/mm(3) , and submassive necrosis was associated with younger age. Hepatitis B demonstrated no association.

CONCLUSION

In a high HIV burden area, drug-induced liver injury due to antiretroviral therapy and cotrimoxazole was a frequent clinicopathological finding; Mycobacterium tuberculosis was the leading opportunistic infection, with more than half of patients fulfilling criteria for tuberculosis immune reconstitution syndrome; liver biopsy remains a useful diagnostic procedure in this setting.

A pharmacogenetics study in Mozambican patients treated with nevirapine: full resequencing of TRAF3IP2 gene shows a novel association with SJS/TEN susceptibility

Steven–Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are severe adverse drug reactions, characterized by extensive epidermal detachment and erosions of mucous membrane. SJS/TEN is one of the most serious adverse reactions to Nevirapine (NVP) treatment, commonly used in developing countries as first-line treatment of human immunodeficiency virus infection. In the last years TRAF3IP2 gene variants had been described as associated with susceptibility to several diseases such as psoriasis and psoriatic arthritis. We hypothesized that this gene, involved in immune response and in NF-κB activation, could also be implicated in the SJS/TEN susceptibility. We performed a full resequencing of TRAF3IP2 gene in a population of patients treated with NVP. Twenty-seven patients with NVP-induced SJS/TEN and 78 controls, all from Mozambique, were enrolled. We identified eight exonic and three intronic already described variants. The case/control association analysis highlighted an association between the rs76228616 SNP in exon 2 and the SJS/TEN susceptibility. In particular, the variant allele (C) resulted significantly associated with a higher risk to develop SJS/TEN (p = 0.012 and OR = 3.65 (95% CI 1.33–10.01)). A multivariate analysis by logistic regression confirmed its significant contribution (p = 0.027, OR = 4.39 (95% CI 1.19–16.23)). In conclusion, our study suggests that a variant in TRAF3IP2 gene could be involved in susceptibility to SJS/TEN.

An assessment of adverse drug reactions among HIV positive patients receiving antiretroviral treatment in South Africa

BACKGROUND

Antiretroviral treatment (ART) has been effective in reducing HIV/AIDS related morbidity and mortality. However, the use and uptake of ART has resulted in adverse reactions, due mainly to the medicine's toxicity and interactions with other medicines. The timing of adverse drug reactions (ADRs) among these patients is a critical public health issue for antiretroviral (ARV) treatment adherence and retention. Reliable monitoring of HIV patients on ART is through a structured pharmacovigilance surveillance system. However, recurrent nature of these data pose challenges in their analyses. This study aimed at modelling the timing of ADR events in HIV patients on ART using correlated time-to-event models.

METHODS

The data concern 590 HIV patients registered onto the Medunsa National ARV Pharmacovigilance Surveillance System within 6 months of ART initiation between February 2007 and July 2011. Recurrent times of ADRs and baseline characteristics: patient gender, and age, ART regimen, clinic and initiation period were extracted from the data. The recurrent ADR events data were modelled using both shared frailty and marginal models on the five patients' characteristics as covariates.

RESULTS

Out of 590 patients, 67% were female, 68% started on regimen: Stavudine, Lamivudine and Efavirenz; 37% had experienced at least one ADR and 67% started ART in 2009-2011. Age (p-value = 0.0210), clinic (p-value < 0.0001) and period of ART initiation (p-value = 0.0002) were significantly associated with timing of first ADR. There was a significantly higher rates of ADR recurrences in patients aged 38-44 years [HR = 2.45; 95% CI = (1.47; 4.10)] vs. 30 years and less, patients taking regimen: Zidovudine, Lamivudine and Nevarapine) vs. regimen: Stavudine, Lamivudine and Efavirenz [HR = 2.09; 95% CI = (1.35; 3.22)], while the rate was lower among those who started ART in 2009-2011 vs. those who initiated in 2007-2008 [HR = 0.55; 95% CI = (0.40; 0.76)].

CONCLUSION

More realistic time-to-event models for recurrent events data have been used to analyse timing of ADR events in HIV patients taking ARV treatment. Age, antiretroviral regimen type and period of initiation of ART were associated with the timing of HIV/AIDS drug related adverse reactions regardless of the analysis model used. This study has public health policy implications in addressing the added morbidity among HIV patients taking ARV treatment in the context of universal scaling up of ARV treatment.

Chronic liver disease in the human immunodeficiency virus patient

There are an estimated 40 million HIV infected individuals worldwide, with chronic liver disease being the 2nd leading cause of mortality in this population. Elevated liver functions are commonly noted in HIV patients and the etiologies are varied. Viral hepatitis B and C, fatty liver and drug induced liver injury are more common. Treatment options for viral hepatitis C are rapidly evolving and are promising, but treatments are limited for the other conditions and is primarily supportive. Opportunistic infections of the liver are now uncommon. Irrespective of etiology, management requires referral to specialized centers and with due diligence mortality can be reduced.

Highly active antiretroviral therapy-related hepatotoxicity in human immunodeficiency virus and hepatitis C virus co-infected patients with advanced liver fibrosis in Taiwan

BACKGROUND

The prevalence of patients co-infected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) is higher in Taiwan than in Western countries. This study aimed to analyze the frequency and risk factors for highly active antiretroviral therapy (HAART)-related liver toxicity in patients co-infected with HIV and HCV with advanced liver fibrosis in Taiwan.

METHODS

This retrospective cohort study included 228 HAART-experienced and HAART-naïve patients who were co-infected with HIV and HCV from January 2013 to December 2013 in Taiwan. Transaminase elevation (TE) was defined by grades. Fibrosis 4 score and aspartate-to-platelet ratio index were used to evaluate liver fibrosis. Cox proportional hazard regression model was used to analyze the risk factors for time to TE events.

RESULTS

A total of 228 patients were included. Only two episodes (1.28%) of high-grade TE were observed. The overall prevalence rate of TE was 16%, and the incidence was 1.38 cases/100 patient-months. Two predictive factors of TE were the initiation of HAART during the study period and CD4 cell count less than 350 cells/mm(3). Subgroup analysis showed that HAART improved liver fibrosis status in patients who had advanced liver fibrosis at baseline (p = 0.033).

CONCLUSION

The frequency of HAART-related TE in HIV and HCV co-infected patients in Taiwan was much lower than that observed in previous studies. Pre-existing advanced liver fibrosis had no influence on the frequency of TE. The use of HAART showed benefits on liver fibrosis progression in patients with underlying advanced liver fibrosis.

Differential responses of human hepatocytes to the non-nucleoside HIV-1 reverse transcriptase inhibitor nevirapine

Nevirapine is a non-nucleoside reverse transcriptase (RT) inhibitor used for the treatment of AIDS and the prevention of mother-to-child transmission of HIV-1. Despite its therapeutic benefits, treatment with nevirapine has been associated with significant incidences of liver and dermal toxicity. The present study examined the effects of nevirapine on cell growth and death in human hepatocyte HepG2 cells and THLE2 cells and the possible pathways involved in these effects. The concentrations of nevirapine inhibiting 50% cell growth were similar for both cell lines. Nevirapine (0-250 µM) treatment caused a slight increase in the amount of lactate dehydrogenase released into the medium. Apoptotic cell death did not contribute to the decrease in viable cells. Exposing of HepG2 cells to nevirapine caused G2/M phase arrest, and the activity of senescence-associated β-galactosidase was not altered. In THLE2 cells, the percentage of cells in G1/G0 phase was increased and cellular senescence was induced in a concentration-dependent manner. Endogenous non-telomeric RT activity was not detected in either cell line. Western blot analysis indicated lower levels of p53 and phospho-p53 (ser15) in HepG2 cells as compared to THLE2 cells; no significant changes in p53 or phospho-p53 (ser15) were noted with nevirapine treatment. These data demonstrate that nevirapine inhibits cell growth, induces cell cycle arrest at different phases, and has different effects on cellular senescence in HepG2 cells and THLE2 cells. The differential responses appear to be related to differences in the basal levels of p53 in the HepG2 cells and THLE2 cells.

WHO guidance on the prevention of viral hepatitis B and C among people who inject drugs

Viral hepatitis B and C (HBV, HCV) disproportionately affect people who inject drugs (PWID) across the world. To date there has been little global action focusing on prevention, care and treatment of HBV and HCV among PWID. Here we report on the development process and discuss the implications of evidence informed WHO Guidelines for the Prevention of HBV and HCV in PWID. The World Health Organization (WHO) convened a Guideline Development Panel to develop recommendations on the prevention of HBV and HCV among PWID. The process followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. It included the development of PICO (Population, Interventions, Comparator, Outcomes) questions and conducting systematic reviews. Quality of evidence was classified into 4 levels: high, moderate, low, and very low. In the process of moving from evidence to recommendations, the following were considered: quality of evidence, balance of benefits and harms, community values and preferences and resource use. The WHO recommendations include the following for working with PWID: offer the rapid HBV vaccination regimen; offer incentives to increase uptake and completion of the HBV vaccine schedule; needle and syringe programs should also provide low dead-space syringes for distribution; and offer peer interventions to reduce the incidence of viral hepatitis. This guideline complements other WHO documents regarding PWID, including HIV prevention initiatives such as needle and syringe programs and opioid substitution therapy. This guidance offers a first step in the prevention of HBV and HCV among PWID. However, the lack of high quality evidence in this area necessitates further research and resources for implementation.

Hepatotoxicity and drug interactions in liver transplant candidates and recipients

In this article the medications that have been shown to increase rates of drug-induced liver injury in patients with cirrhosis and the important drug-drug interactions in recipients of liver transplantation are reviewed. In general, the risk of drug-induced liver injury in patients with cirrhosis does not seem to be higher when compared with the noncirrhotic population. There are, however, 2 classes of agents that have been implicated-medications used to treat tuberculosis and medications used to treat human immunodeficiency virus infection. However, with careful monitoring, even significant interactions can be effectively managed.

The interaction of CD4 T-cell count and nevirapine hepatotoxicity in China: a change in national treatment guidelines may be warranted

OBJECTIVES

Nevirapine (NVP), a still widely used nonnucleoside reverse transcriptase inhibitor, can cause severe hepatotoxicity. Previous studies suggest that CD4 cell counts more than 250 cells per microliter in women and more than 400 cells per microliter in men are risk factors for NVP-related hepatotoxicity. These studies have informed Chinese national treatment guidelines. We evaluate whether current Chinese guidelines for NVP use are appropriate.

METHODS

Longitudinal data were pooled from 2 clinical trials between 2005 and 2009 across mainland China. Five hundred sixty-six antiretroviral therapy-naive Chinese patients were given NVP-containing antiretroviral therapy for 24 weeks. Hepatotoxicity was defined as alanine aminotransferase, aspartate transaminase, or total bilirubin level greater than 1.25 times the upper limit of normal range. Severe hepatotoxicity was defined as greater than 5 times the upper limit of normal range.

RESULTS

One hundred ninety-seven (36.1%) patients developed hepatotoxicity during treatment, including 42 (7.7%) patients with severe hepatotoxicity. CD4 cell count more than 250 cells per microliter was an independent predictor for hepatotoxicity both in men [relative risk = 1.22 (95% confidence interval: 1.04 to 1.44)] and in women [relative risk = 1.72 (95% confidence interval: 1.20 to 2.46)]. Severe hepatotoxicity was also more common among all persons with CD4 >250 cells per microliter.

CONCLUSIONS

Hepatotoxicity was a common adverse effect of NVP among men and women with CD4 >250 cells per microliter. Chinese treatment guidelines should be considered to reflect this risk.

HIV protease inhibitors in pregnancy : pharmacology and clinical use

The impact of antiretroviral therapy (ART) on the natural history of HIV-1 infection has resulted in dramatic reductions in disease-associated morbidity and mortality. Additionally, the epidemiology of HIV-1 infection worldwide is changing, as women now represent a substantial proportion of infected adults. As more highly effective and tolerable antiretroviral regimens become available, and as the prevention of mother-to-child transmission becomes an attainable goal in the management of HIV-infected individuals, more and more HIV-positive women are choosing to become pregnant and have children. Consequently, it is important to consider the efficacy and safety of antiretroviral agents in pregnancy. Protease inhibitors are a common class of medication used in the treatment of HIV-1 infection and are increasingly being used in pregnancy. However, several studies have raised concerns regarding pharmacokinetic alterations in pregnancy, particularly in the third trimester, which results in suboptimal drug concentrations and a theoretically higher risk of virologic failure and perinatal transmission. Drug level reductions have been observed with each individual protease inhibitor and dose adjustments in pregnancy are suggested for certain agents. Furthermore, studies have also raised concerns regarding the safety of protease inhibitors in pregnancy, particularly as they may increase the risk of pre-term birth and metabolic disturbances. Overall, protease inhibitors are safe and effective for the treatment of HIV-infected pregnant women. Specifically, ritonavir-boosted lopinavir- and atazanavir-based regimens are preferred in pregnancy, while ritonavir-boosted darunavir- and saquinavir-based therapies are reasonable alternatives. This paper reviews the use of protease inhibitors in pregnancy, focusing on pharmacokinetic and safety considerations, and outlines the recommendations for use of this class of medication in the HIV-1-infected pregnant woman.

Liver transplantation for acute liver failure due to efavirenz hepatotoxicity: the importance of routine monitoring

We present the first case report in the UK of acute liver failure caused by efavirenz therapy culminating in liver transplantation. A 26-year-old Zimbabwean woman commenced emtricitabine, tenofovir and efavirenz (Atripla) in December 2011. Her liver function tests at baseline and at 20 days after initiating antiretroviral therapy were normal. At three months of therapy her blood tests haemolysed and were not processed. She had previously missed follow-up appointments and on this occasion failed to return for repeat tests. She was not seen again until after six months of antiretroviral therapy when she presented to her general practitioner with acute liver failure. Her condition deteriorated and she required liver transplantation. She recovered well and re-started antiretroviral therapy to good effect. The case illustrates the value of routine monitoring after initiating antiretroviral therapy and the fundamental importance of engaging patients in long-term management to ensure safe treatment.

Current challenges and controversies in drug-induced liver injury

Current key challenges and controversies encountered in the identification of potentially hepatotoxic drugs and the assessment of drug-induced liver injury (DILI) are covered in this article. There is substantial debate over the classification of DILI itself, including the definition and validity of terms such as 'intrinsic' and 'idiosyncratic'. So-called idiosyncratic DILI is typically rare and requires one or more susceptibility factors in individuals. Consequently, it has been difficult to reproduce in animal models, which has limited the understanding of its underlying mechanisms despite numerous hypotheses. Advances in predictive models would also help to enable preclinical elimination of drug candidates and development of novel biomarkers. A small number of liver laboratory tests have been routinely used to help identify DILI, but their interpretation can be limited and confounded by multiple factors. Improved preclinical and clinical biomarkers are therefore needed to accurately detect early signals of liver injury, distinguish drug hepatotoxicity from other forms of liver injury, and differentiate mild from clinically important liver injury. A range of potentially useful biomarkers are emerging, although so far most have only been used preclinically, with only a few validated and used in the clinic for specific circumstances. Advances in the development of genomic biomarkers will improve the prediction and detection of hepatic injury in future. Establishing a definitive clinical diagnosis of DILI can be difficult, since it is based on circumstantial evidence by excluding other aetiologies and, when possible, identifying a drug-specific signature. DILI signals based on standard liver test abnormalities may be affected by underlying diseases such as hepatitis B and C, HIV and cancer, as well as the concomitant use of hepatotoxic drugs to treat some of these conditions. Therefore, a modified approach to DILI assessment is justified in these special populations and a suggested framework is presented that takes into account underlying disease when evaluating DILI signals in individuals. Detection of idiosyncratic DILI should, in some respects, be easier in the postmarketing setting compared with the clinical development programme, since there is a much larger and more varied patient population exposure over longer timeframes. However, postmarketing safety surveillance is currently limited by the quantity and quality of information available to make an accurate diagnosis, the lack of a control group and the rarity of cases. The pooling of multiple healthcare databases, which could potentially contain different types of patient data, is advised to address some of these deficiencies.

Drug-induced liver injury: the role of drug metabolism and transport

Many studies have pinpointed the significant contribution of liver-mediated drug metabolism and transport to the complexity of drug-induced liver injury (DILI). Phase I cytochrome P450 (CYP450) enzymes can lead to altered drug metabolism and formation of toxic metabolites, whilst Phase II enzymes are also associated with DILI. The emerging role of hepatic transporters in regulating the movement of endogenous and exogenous chemicals (e.g., bile acids and drugs) across cellular and tissue membranes is critical in determining the pathophysiology of liver disease as well as drug toxicity and efficacy. Genetic and environmental factors can have a significant impact on drug metabolism and transporter proteins, consequently increasing the risk of DILI in susceptible individuals. The assessment of these factors therefore represents an important approach for predicting and preventing DILI, by better understanding the pharmacological profile of a specific drug. This review focuses on the mechanisms of DILI associated with drug metabolism and hepatic transport, and how they can be influenced by underlying factors.

Nevirapine versus efavirenz for patients co-infected with HIV and tuberculosis: a randomised non-inferiority trial

BACKGROUND

In countries with a high incidence of HIV and tuberculosis co-infection, nevirapine and efavirenz are widely used as antiretroviral therapy but both interact with antituberculosis drugs. We aimed to compare efficacy and safety of a nevirapine-based antiretroviral therapy (started at full dose) with an efavirenz-based regimen in co-infected patients.

METHODS

We did a multicentre, open-label, randomised, non-inferiority trial at three health centres in Maputo, Mozambique. We enrolled adults (≥18 years) with tuberculosis and previously untreated HIV infection (CD4 cell counts <250 cells per μL) and alanine aminotransferase and total bilirubin concentrations of less than five times the upper limit of normal. 4-6 weeks after the start of tuberculosis treatment, we randomly allocated patients (1:1) with central randomisation, block sizes of two to six, and stratified by site and CD4 cell count to nevirapine (200 mg twice daily) or efavirenz (600 mg once daily), plus lamivudine and stavudine. The primary endpoint was virological suppression at 48 weeks (HIV-1 RNA <50 copies per mL) in all patients who received at least one dose of study drug (intention-to-treat population); death and loss to follow-up were recorded as treatment failure. The non-inferiority margin for the difference of efficacy was 10%. We assessed efficacy in intention-to-treat and per-protocol populations and safety in all patients who received study drug. This study is registered with ClinicalTrials.gov, number NCT00495326.

FINDINGS

Between October, 2007, and March, 2010, we enrolled 285 patients into each group. 242 (85%) patients in the nevirapine group and 233 (82%) patients in the efavirenz group completed follow-up. In the intention-to-treat population, 184 patients (64·6%, 95% CI 58·7-70·1) allocated nevirapine achieved virological suppression at week 48, as did 199 patients (69·8%, 64·1-75·1) allocated efavirenz (one-sided 95% CI of the difference of efficacy 11·7%). In the per-protocol population, 170 (70·0%, 63·8-75·7) of 243 patients allocated nevirapine achieved virological suppression at week 48, as did 194 (78·9%, 73·2-83·8) of 246 patients allocated efavirenz (one-sided 95% CI 15·4%). The median CD4 cell count at randomisation was 89 cells per μL. 15 patients substituted nevirapine with efavirenz and six patients substituted efavirenz with nevirapine. 20 patients allocated nevirapine (7%) had grade 3-4 increase of alanine aminotransferase compared with 17 patients allocated efavirenz (6%). Three patients had severe rash after receipt of nevirapine (1%) but no patients did after receipt of efavirenz. 18 patients in the nevirapine group died, as did 17 patients in the efavirenz group.

INTERPRETATION

Although non-inferiority of the nevirapine-regimen was not shown, nevirapine at full dose could be a safe, acceptable alternative for patients unable to tolerate efavirenz.

FUNDING

French Research Agency for HIV/AIDS and hepatitis (ANRS).

Compartmentalization and antiviral effect of efavirenz metabolites in blood plasma, seminal plasma, and cerebrospinal fluid

Efavirenz (EFV) is one of the most commonly prescribed antiretrovirals for use in the treatment of human immunodeficiency virus (HIV) infection. EFV is extensively metabolized by cytochrome P450 to a number of oxygenated products; however, the pharmacologic activity and distribution of these metabolites in anatomic compartments have yet to be explored. The systemic distribution of EFV oxidative metabolites was examined in blood plasma, seminal plasma, and cerebrospinal fluid from subjects on an EFV-based regimen. The 8-hydroxy EFV metabolite was detected in blood plasma, seminal plasma, and cerebrospinal fluid, with median concentrations of 314.5 ng/ml, 358.5 ng/ml, and 3.37 ng/ml, respectively. In contrast, 7-hydroxy and 8,14-hydroxy EFV were only detected in blood plasma and seminal plasma with median concentrations of 8.84 ng/ml and 10.23 ng/ml, and 5.63 ng/ml and 5.43 ng/ml, respectively. Interestingly, protein-free concentrations of metabolites were only detectable in seminal plasma, where a novel dihdyroxylated metabolite of EFV was also detected. This accumulation of protein-free EFV metabolites was demonstrated to be the result of differential protein binding in seminal plasma compared with that of blood plasma. In addition, the oxidative metabolites of EFV did not present with any significant pharmacologic activity toward HIV-1 as measured using an HIV green fluorescent protein single-round infectivity assay. This study is the first to report the physiologic distribution of metabolites of an antiretroviral into biologic compartments that the virus is known to distribute and to examine their anti-HIV activity. These data suggest that the male genital tract may be a novel compartment that should be considered in the evaluation of drug metabolite exposure.

Pharmacological and clinical evidence of nevirapine immediate- and extended-release formulations

We reviewed the current information available on nevirapine immediate- and extended-release formulations and its role in single-dose and combination antiretroviral therapy. Nevirapine was approved in 1996 and was the first non-nucleoside reverse-transcriptase inhibitor available for the treatment of HIV-1 infection. Nevirapine has demonstrated good efficacy and a well-characterized safety profile. A major drawback is the low genetic barrier, allowing the emergence of resistance in the presence of single mutations in the reverse-transcriptase gene. This shortcoming is particularly relevant when nevirapine is administered in a single dose to prevent mother-to-child transmission of HIV-1 infection, compromising the efficacy of future non-nucleoside reverse transcriptase-inhibitor regimens. Studies published recently have probed the noninferiority of nevirapine compared to ritonavir-boosted atazanavir with both tenofovir disoproxil fumarate and emtricitabine in antiretroviral treatment-naïve patients. In 2011, a new formulation of nevirapine (nevirapine extended release) that allowed once-daily dosing was approved by the Food and Drug Administration and by the European Medicines Agency. VERxVe, a study comparing nevirapine extended release with nevirapine immediate release in antiretroviral treatment-naïve patients, and TRANxITION, a study carried out in antiretroviral treatment-experienced patients who switched therapy from nevirapine immediate release to nevirapine extended release, provided data on the noninferiority of the new formulation of nevirapine compared with nevirapine immediate release in terms of efficacy and safety. Nevirapine extended release will further increase the durability and persistence of nevirapine-containing antiretroviral therapy, allowing once-daily dosing regimens.

The pharmacogenetics of antiretroviral therapy

PURPOSE OF REVIEW

Although the past 20 years have seen many advances in HIV pharmacotherapy, host variability has only been more recently recognized as an important driver of both treatment response and toxicity. This review will focus on the importance of variability in drug metabolizing enzymes and the potential research and clinical applications of these findings in HIV care.

RECENT FINDINGS

The treatment of HIV is complex and involves chronic treatment with multiple drugs and drug classes. Recent research has been important in uncovering genetic differences in drug metabolizing and drug transporter genes, which underpin dose-dependent toxicity and efficacy, but also in genes defining differences in immune response and human leukocyte antigen genes, which restrict processes that are less dependent on the drug dose.

SUMMARY

The advancement of pharmacogenetics will continue to further our knowledge of disease-drug interactions and pathogenesis. Ultimately, the goals of pharmacogenetics and pharmacogenomics in HIV medicine will be the development of the right drugs for the right patient or population. The strong association between HLA-B5701 and abacavir hypersensitivity reaction shows promise for a genetic screening test to be feasibly incorporated into clinical practice. The clinical applicability of many findings demonstrating associations between single nucleotide polymorphisms, particularly in drug metabolism and transporter genes and drug efficacy and toxicity, are currently uncertain.

HIV and viral hepatitis C coinfection in people who inject drugs: implications of new direct acting antivirals for hepatitis C virus treatment

PURPOSE OF REVIEW

The recent major shift toward oral direct acting hepatitis C virus (HCV) treatments has the potential to revolutionize the global response to HCV. People who inject drugs (PWID) are a large key affected population who stand to benefit from these new medications.

RECENT FINDINGS

There is a large number of new drug classes and targets with activity against HCV. Although effective for HCV treatment in monoinfection and coinfection with HIV, most direct-acting antivirals (DAAs) remain within the research pipeline, with only two having achieved regulatory approval to date. Clinical trial data are not available regarding HCV treatment for PWID with DAAs. This article reviews clinical data on HCV treatment for a number of promising compounds in HCV monoinfection and coinfection with HIV and discusses the barriers facing PWID in scale-up and roll-out of DAAs in the coming years.

SUMMARY

DAAs have the potential to revolutionize HCV treatment. There will be significant access barriers for people who inject drugs to these new medications.

The role of the immune system in nevirapine-induced subclinical liver injury of a rat model

In this study, the role of the immune system in nevirapine- (NVP-) induced subclinical liver injury was investigated by observing for changes of some immune parameters during the initial stages of NVP-induced hepatotoxicity in a rat model. In the acute phase, two test-groups of 10 Sprague-Dawley rats each were administered with bacterial lipopolysaccharide (LPS) or saline (S) intraperitoneally, followed by oral NVP, after which 5 rats from each group were sacrificed at 6 and 24 hours. For the chronic phase, two groups of 15 rats each received daily NVP, and on days 7, 14, and 21, five rats from each group were administered with either LPS or S, followed by that day's NVP dose, and were sacrificed 24 hours later. NVP caused liver injury up to seven days and progressively increased IL-2 and IFN-γ levels and lymphocyte count over the 21 days. NVP-induced liver injury was characterized by apoptosis and degeneration changes, while, for LPS, it was cell swelling, leukostasis, and portal inflammation. Coadministration of NVP and LPS attenuated NVP-induced liver injury. In conclusion, the immune system is involved in NVP toxicity, and the LPS effects may lay the clue to development of therapeutic strategies against NVP-induced hepatotoxicity.

Efficacy and safety of rilpivirine in treatment-naive, HIV-1-infected patients with hepatitis B virus/hepatitis C virus coinfection enrolled in the Phase III randomized, double-blind ECHO and THRIVE trials

OBJECTIVES

The efficacy and hepatic safety of the non-nucleoside reverse transcriptase inhibitors rilpivirine (TMC278) and efavirenz were compared in treatment-naive, HIV-infected adults with concurrent hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection in the pooled week 48 analysis of the Phase III, double-blind, randomized ECHO (NCT00540449) and THRIVE (NCT00543725) trials.

METHODS

Patients received 25 mg of rilpivirine once daily or 600 mg of efavirenz once daily, plus two nucleoside/nucleotide reverse transcriptase inhibitors. At screening, patients had alanine aminotransferase/aspartate aminotransferase levels ≤5× the upper limit of normal. HBV and HCV status was determined at baseline by HBV surface antigen, HCV antibody and HCV RNA testing.

RESULTS

HBV/HCV coinfection status was known for 670 patients in the rilpivirine group and 665 in the efavirenz group. At baseline, 49 rilpivirine and 63 efavirenz patients [112/1335 (8.4%)] were coinfected with either HBV [55/1357 (4.1%)] or HCV [57/1333 (4.3%)]. The safety analysis included all available data, including beyond week 48. Eight patients seroconverted during the study (rilpivirine: five; efavirenz: three). A higher proportion of patients achieved viral load <50 copies/mL (intent to treat, time to loss of virological response) in the subgroup without HBV/HCV coinfection (rilpivirine: 85.0%; efavirenz: 82.6%) than in the coinfected subgroup (rilpivirine: 73.5%; efavirenz: 79.4%) (rilpivirine, P = 0.04 and efavirenz, P = 0.49, Fisher's exact test). The incidence of hepatic adverse events (AEs) was low in both groups in the overall population (rilpivirine: 5.5% versus efavirenz: 6.6%) and was higher in HBV/HCV-coinfected patients than in those not coinfected (26.7% versus 4.1%, respectively).

CONCLUSIONS

Hepatic AEs were more common and response rates lower in HBV/HCV-coinfected patients treated with rilpivirine or efavirenz than in those who were not coinfected.

The effect of HIV infection, immunodeficiency, and antiretroviral therapy on the risk of hepatic dysfunction

BACKGROUND

Limited data exists regarding the effect of chronic HIV infection on the liver. We sought to characterize the hepatic risks of HIV infection, immunodeficiency, and cumulative use of antiretroviral therapy (ART).

METHODS

Adult HIV infected and 10:1 age-matched and sex-matched HIV-uninfected individuals were followed for incident hepatic dysfunction or hepatic dysfunction-related death. Multivariable Poisson regression models were used to obtain incident rate ratios, adjusting for multiple hepatic risk factors including alcohol/drug abuse, hepatitis B and C, and diabetes.

RESULTS

We identified 20,775 HIV-infected and 215,158 HIV-uninfected individuals. HIV-infected individuals had a significantly greater overall risk compared with HIV-uninfected individuals of both hepatic dysfunction and hepatic dysfunction-related death. The highest risk was seen in patients with low CD4 cell counts not on ART [adjusted rate ratio of hepatic dysfunction-related death 59.4; (95% confidence interval: 39.3 to 89.7), P < 0.001; hepatic dysfunction, adjusted rate ratio 15.7 (95% confidence interval: 11.4 to 21.6), P < 0.001]. In an HIV-infected only model, factors that increased risk included low CD4 cell count, high HIV RNA level, alcohol/drug abuse, hepatitis B or C coinfection, and diabetes. Longer cumulative exposure to ART did not increase risk, regardless of therapy class.

CONCLUSIONS

HIV-infected individuals have a higher risk of hepatic dysfunction and hepatic dysfunction-related death compared with HIV-uninfected individuals, even with adjustment for known hepatic risk factors. Hepatic outcomes were associated with lower CD4+ T-cell counts but not with longer cumulative ART exposure. These findings provide indirect evidence supporting early use of ART to reduce the risk for hepatic-related complications.

NNRTIs: pharmacological data

One of the choice criteria for antiretroviral therapy, once the viral load is controlled, is long-term treatment safety. Safety, despite similarities in each therapeutic class, can differ significantly from one agent to another, according to their respective pharmacokinetic and pharmacodynamic properties. We reviewed data on two very well-known NNRTIs, efavirenz and nevirapine, in this context. The pharmacokinetic properties of both agents are presented along with their impact on residual viremia and viral reservoirs, as well as their clinical consequences. The implications for the penetration of these antiretroviral drugs in the CNS and in female and male genital tracts are also discussed. Pharmacogenetics could become an interesting tool. Finally, the availability of new NNRTIs has recently boosted this therapeutic class, even if their long-term properties remain to be assessed. The consideration of all this data stresses the importance of communication among clinicians, virologists, and pharmacologists before choosing a treatment.