Hy's law: predicting serious hepatotoxicity

Low-density lipoprotein lowering in 2013 by nonstatin agents: the discovery and development of promising novel targeted therapies

Dyslipidemia is a major risk factor for the development of coronary artery disease, a leading cause of morbidity and mortality worldwide. Lowering low-density lipoprotein (LDL) has significantly reduced the risk of death and other major cardiovascular events, and statins remain the therapy of choice. However, as some patients are limited by the side effects of statins, cannot achieve their target LDL on statin therapy, or have other abnormalities in their lipid profile, alternative agents are being developed. In this review, we highlight the major classes of novel nonstatin LDL-lowering agents that are currently in various stages of development. Although many hold great promise, the results of large Phase III trials will be needed to definitely establish the efficacy, safety, and clinical utility of these agents in the general population.

Oral BG-12 (dimethyl fumarate) for relapsing-remitting multiple sclerosis: a review of DEFINE and CONFIRM. Evaluation of: Gold R, Kappos L, Arnold D, et al. Placebo-controlled phase 3 study of oral BG-12 for relapsing multiple sclerosis. N Engl J Med 2012;367:1098-107; and Fox RJ, Miller DH, Phillips JT, et al. Placebo-controlled phase 3 study of oral BG-12 or glatiramer in multiple sclerosis. N Engl J Med 2012;367:1087-97

INTRODUCTION

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease of the central nervous system involving inflammation, chronic demyelination and axonal loss. MS affects more than 2 million people worldwide.

AREAS COVERED

This article aims to summarize the findings from two pivotal 2-year, randomized, double-blind, placebo-controlled, Phase III studies of BG-12 (dimethyl fumarate) for relapsing-remitting MS (RRMS): DEFINE (Determination of the Efficacy and Safety of Oral Fumarate in RRMS) and CONFIRM (Comparator and an Oral Fumarate in RRMS). Results from both studies demonstrated that BG-12 provides clinical and radiological efficacy over 2 years across a range of outcomes. These results were apparent as early as 12 weeks and sustained over the course of both studies. BG-12 was found to have an acceptable safety profile, with a similar overall incidence of adverse events across all treatment groups.

EXPERT OPINION

The combination of robust efficacy, ease of administration and established safety profile is unique to a new therapy in MS. Findings from the pivotal Phase III studies support BG-12 as a potential initial oral treatment for patients with RRMS or as an alternative to other currently available therapies.

Validity of diagnostic codes to identify cases of severe acute liver injury in the US Food and Drug Administration's Mini-Sentinel Distributed Database

PURPOSE

The validity of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes to identify diagnoses of severe acute liver injury (SALI) is not well known. We examined the positive predictive values (PPVs) of hospital ICD-9-CM diagnoses in identifying SALI among health plan members in the Mini-Sentinel Distributed Database (MSDD) for patients without liver/biliary disease and for those with chronic liver disease (CLD).

METHODS

We selected random samples of members (149 without liver/biliary disease; 75 with CLD) with a principal hospital diagnosis suggestive of SALI (ICD-9-CM 570, 572.2, 572.4, 572.8, 573.3, 573.8, or V42.7) in the MSDD (2009-2010). Medical records were reviewed by hepatologists to confirm SALI events. PPVs of codes and code combinations for confirmed SALI were determined by CLD status.

RESULTS

Among 105 members with available records and no liver/biliary disease, SALI was confirmed in 26 (PPV, 24.7%; 95%CI, 16.9-34.1%). Combined hospital diagnoses of acute hepatic necrosis (570) and liver disease sequelae (572.8) had high PPV (100%; 95%CI, 59.0-100%) and identified 7/26 (26.9%) events. Among 46 CLD members with available records, SALI was confirmed in 19 (PPV, 41.3%; 95%CI, 27.0-56.8%). Acute hepatic necrosis (570) or hepatorenal syndrome (572.4) plus any other SALI code had a PPV of 83.3% (95%CI, 51.6-97.9%) and identified 10/19 (52.6%) events.

CONCLUSIONS

Most individual hospital ICD-9-CM diagnoses had low PPV for confirmed SALI events. Select code combinations had high PPV but did not capture all events.

[Liver dysfunctions in intensive care patients--consequences for the treatment of invasive Candida infections]

Liver dysfunction is common among patients on intensive care units (ICU) due to sepsis, chronic liver disease, ischemic hepatitis, drug toxicity and intensive care measures. Critically ill patients with invasive fungal infections should therefore be treated with antifungals that are not metabolized by the liver. This may help to avoid therapeutic complications by drug accumulation, inadequate dosages or drug-drug interactions. Echinocandins are established as the antifungal class of choice in the treatment of invasive Candida infections. Anidulafungin is not hepatically metabolized and may be used without dose adjustments in patients with severe liver dysfunction. It has no known clinically relevant drug interactions. In the primary endpoint of the randomized pivotal trial in patients with candidemia or invasive candidiasis, anidulafungin was statistically superior versus the former standard therapy (fluconazole), with a favourable overall safety profile. More recent study data particularly in ICU patients confirm the efficacy of anidulafungin for these patient groups. Therefore, anidulafungin is an important antifungal treatment option for patients with liver dysfunction.

Trabectedin as single agent in the salvage treatment of heavily treated ovarian cancer patients: a retrospective, multicenter study

OBJECTIVE

The aim of this multicenter, retrospective study was to evaluate the efficacy and the safety of single agent Trabectedin (ET-743, Yondelis) in very heavily treated, relapsed ovarian cancer (ROC) patients.

PATIENTS AND METHODS

Response to treatment was classified according to RECIST criteria. Progression-free (PFS), and overall survival (OS) were also assessed.

RESULTS

98 patients were analyzed (originally 67 platinum sensitive, and 31 platinum refractory/resistant). Median number of previous regimens was 4 (range: 1-6). In the whole population, overall response rate (ORR) was 27.5%; stable disease (SD) was observed in 33 patients (33.6%), and clinical benefit was achieved in 60 cases (61.2%). ORR was 38.6% in fully platinum sensitive population, and 26.1% in partially platinum sensitive patients. In platinum refractory/resistant disease, ORR was 12.9%. Overall, median PFS and OS were 5, and 13 months, respectively. Patients responding to Trabectedin showed a more favorable PFS (median = 9 months) than patients with SD (median = 6 months), or progression (median = 2 months). Median OS of responding patients was 18 months compared to 14 months in SD patients, and 9 months in progressing patients. Grade 3-4 neutropenia was observed in 17 (17.3%) patients. Transient and non-cumulative Grade 3-4 AST and ALT level elevation was found in 7 (7.1%), and 13 (13.3%) cases, respectively. There was 1 case of Grade 3, and 1 case of Grade 4 cardiac toxicity.

CONCLUSIONS

Trabectedin, as a single agent, retains its efficacy in terms of rate of ORR and clinical benefit in heavily treated ROC patients, especially in the group of platinum sensitive disease.

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.

Idiosyncratic adverse drug reactions: current concepts

Idiosyncratic drug reactions are a significant cause of morbidity and mortality for patients; they also markedly increase the uncertainty of drug development. The major targets are skin, liver, and bone marrow. Clinical characteristics suggest that IDRs are immune mediated, and there is substantive evidence that most, but not all, IDRs are caused by chemically reactive species. However, rigorous mechanistic studies are very difficult to perform, especially in the absence of valid animal models. Models to explain how drugs or reactive metabolites interact with the MHC/T-cell receptor complex include the hapten and P-I models, and most recently it was found that abacavir can interact reversibly with MHC to alter the endogenous peptides that are presented to T cells. The discovery of HLA molecules as important risk factors for some IDRs has also significantly contributed to our understanding of these adverse reactions, but it is not yet clear what fraction of IDRs have a strong HLA dependence. In addition, with the exception of abacavir, most patients who have the HLA that confers a higher IDR risk with a specific drug will not have an IDR when treated with that drug. Interindividual differences in T-cell receptors and other factors also presumably play a role in determining which patients will have an IDR. The immune response represents a delicate balance, and immune tolerance may be the dominant response to a drug that can cause IDRs.

Genetic characterization to improve interpretation and clinical management of hepatotoxicity caused by tyrosine kinase inhibitors

Tyrosine kinase inhibitors (TKIs) represent important therapeutic alternatives to, or combinations with, traditional cytotoxic chemotherapy. Despite their selective molecular targeting and demonstrated clinical benefit, TKIs produce a range of serious adverse events, including drug-induced liver injury, that require careful patient management to maintain treatment benefit without harm. Genetic characterization of serious adverse events can identify mechanisms of injury and improve safety risk management. This review presents pharmacogenetic comparisons of two approved TKIs, lapatinib and pazopanib, which reveal different mechanisms of injury and inform the characteristics and risk of serious liver injury in treated patients. The data presented demonstrate the utility of genetic studies to investigate drug-induced liver injury and potentially support its management in patients.

Perturbation of bile acid homeostasis is an early pathogenesis event of drug induced liver injury in rats

Drug-induced liver injury (DILI) is a significant consideration for drug development. Current preclinical DILI assessment relying on histopathology and clinical chemistry has limitations in sensitivity and discordance with human. To gain insights on DILI pathogenesis and identify potential biomarkers for improved DILI detection, we performed untargeted metabolomic analyses on rats treated with thirteen known hepatotoxins causing various types of DILI: necrosis (acetaminophen, bendazac, cyclosporine A, carbon tetrachloride, ethionine), cholestasis (methapyrilene and naphthylisothiocyanate), steatosis (tetracycline and ticlopidine), and idiosyncratic (carbamazepine, chlorzoxasone, flutamide, and nimesulide) at two doses and two time points. Statistical analysis and pathway mapping of the nearly 1900 metabolites profiled in the plasma, urine, and liver revealed diverse time and dose dependent metabolic cascades leading to DILI by the hepatotoxins. The most consistent change induced by the hepatotoxins, detectable even at the early time point/low dose, was the significant elevations of a panel of bile acids in the plasma and urine, suggesting that DILI impaired hepatic bile acid uptake from the circulation. Furthermore, bile acid amidation in the hepatocytes was altered depending on the severity of the hepatotoxin-induced oxidative stress. The alteration of the bile acids was most evident by the necrosis and cholestasis hepatotoxins, with more subtle effects by the steatosis and idiosyncratic hepatotoxins. Taking together, our data suggest that the perturbation of bile acid homeostasis is an early event of DILI. Upon further validation, selected bile acids in the circulation could be potentially used as sensitive and early DILI preclinical biomarkers.

Assessment of emerging biomarkers of liver injury in human subjects

Hepatotoxicity remains a major challenge in drug development. Although alanine aminotransferase (ALT) remains the gold standard biomarker of liver injury, alternative biomarker strategies to better predict the potential for severe drug-induced liver injury (DILI) are essential. In this study, we evaluated the utility of glutamate dehydrogenase (GLDH), purine nucleoside phosphorylase (PNP), malate dehydrogenase (MDH), and paraxonase 1 (PON1) as indicators of liver injury in cohorts of human subjects, including healthy subjects across age and gender, subjects with a variety of liver impairments, and several cases of acetaminophen poisoning. In the healthy subjects, levels of GLDH and MDH were not affected by age or gender. Reference ranges for GLDH and MDH in healthy subjects were 1-10 and 79-176U/L, respectively. In contrast, the levels of PON1 and PNP were not consistent across cohorts of healthy subjects. Furthermore, GLDH and MDH had a strong correlation with elevated ALT levels and possessed a high predictive power for liver injury, as determined by ROC analysis. In contrast, PON1 and PNP did not detect liver injury in our study. Finally, evaluation of patients with acetaminophen-induced liver injury provided evidence that both GLDH and MDH might have utility as biomarkers of DILI in humans. This study is the first to evaluate GLDH, MDH, PON1, and PNP in a large number of human subjects and, and it provides an impetus for prospective clinical studies to fully evaluate the diagnostic value of GLDH and MDH for detection of liver injury.

Pretreatment data is highly predictive of liver chemistry signals in clinical trials

PURPOSE

The goal of this retrospective analysis was to assess how well predictive models could determine which patients would develop liver chemistry signals during clinical trials based on their pretreatment (baseline) information.

PATIENTS AND METHODS

Based on data from 24 late-stage clinical trials, classification models were developed to predict liver chemistry outcomes using baseline information, which included demographics, medical history, concomitant medications, and baseline laboratory results.

RESULTS

Predictive models using baseline data predicted which patients would develop liver signals during the trials with average validation accuracy around 80%. Baseline levels of individual liver chemistry tests were most important for predicting their own elevations during the trials. High bilirubin levels at baseline were not uncommon and were associated with a high risk of developing biochemical Hy's law cases. Baseline γ-glutamyltransferase (GGT) level appeared to have some predictive value, but did not increase predictability beyond using established liver chemistry tests.

CONCLUSION

It is possible to predict which patients are at a higher risk of developing liver chemistry signals using pretreatment (baseline) data. Derived knowledge from such predictions may allow proactive and targeted risk management, and the type of analysis described here could help determine whether new biomarkers offer improved performance over established ones.

Drug-induced liver injury: present and future

Liver injury due to prescription and nonprescription medications is a growing medical, scientific, and public health problem. Worldwide, the estimated annual incidence rate of drug-induced liver injury (DILI) is 13.9-24.0 per 100,000 inhabitants. DILI is one of the leading causes of acute liver failure in the US. In Korea, the annual extrapolated incidence of cases hospitalized at university hospital is 12/100,000 persons/year. Most cases of DILI are the result of idiosyncratic metabolic responses or unexpected reactions to medication. There is marked geographic variation in relevant agents; antibiotics, anticonvulsants, and psychotropic drugs are the most common offending agents in the West, whereas in Asia, 'herbs' and 'health foods or dietary supplements' are more common. Different medical circumstances also cause discrepancy in definition and classification of DILI between West and Asia. In the concern of causality assessment, the application of the Roussel Uclaf Causality Assessment Method (RUCAM) scale frequently undercounts the cases caused by 'herbs' due to a lack of previous information and incompatible time criteria. Therefore, a more objective and reproducible tool that could be used for the diagnosis of DILI caused by 'herbs' is needed in Asia. In addition, a reporting system similar to the Drug-Induced Liver Injury Network (DILIN) in the US should be established as soon as possible in Asia.

An Update on Drug-induced Liver Injury

Idiosyncratic drug-induced liver injury (DILI) is an important cause of morbidity and mortality following drugs taken in therapeutic doses. Hepatotoxicity is a leading cause of attrition in drug development, or withdrawal or restricted use after marketing. No age is exempt although adults and the elderly are at increased risk. DILI spans the entire spectrum ranging from asymptomatic elevation in transaminases to severe disease such as acute hepatitis leading to acute liver failure. The liver specific Roussel Uclaf Causality Assessment Method is the most validated and extensively used for determining the likelihood that an implicated drug caused DILI. Asymptomatic elevation in liver tests must be differentiated from adaptation. Drugs producing DILI have a signature pattern although no single pattern is characteristic. Antimicrobial and central nervous system agents including antiepileptic drugs are the leading causes of DILI worldwide. In the absence of a diagnostic test or a biomarker, the diagnosis rests on the evidence of absence of competing causes such as acute viral hepatitis, autoimmune hepatitis and others. Recent studies show that antituberculosis drugs given for active or latent disease are still a major cause of drug-induced liver injury in India and the West respectively. Presence of jaundice signifies a severe disease and entails a worse outcome. The pathogenesis is unclear and is due to a mix of host, drug metabolite and environmental factors. Research has evolved from incriminating candidate genes to genome wide analysis studies. Immediate cessation of the drug is key to prevent or minimize progressive damage. Treatment is largely supportive. N-acetylcysteine is the antidote for paracetamol toxicity. Carnitine has been tried in valproate injury whereas steroids and ursodeoxycholic acid may be used in DILI associated with hypersensitivity or cholestatic features respectively. This article provides an overview of the epidemiology, the patterns of hepatotoxicity, the pathogenesis and associated risk factors besides its clinical management.

Comparisons between in vitro whole cell imaging and in vivo zebrafish-based approaches for identifying potential human hepatotoxicants earlier in pharmaceutical development

Drug-induced liver injury (DILI) is a major cause of attrition during both the early and later stages of the drug development and marketing process. Reducing or eliminating drug-induced severe liver injury, especially those that lead to liver transplants or death, would be tremendously beneficial for patients. Therefore, developing new pharmaceuticals that have the highest margins and attributes of hepatic safety would be a great accomplishment. Given the current low productivity of pharmaceutical companies and the high costs of bringing new medicines to market, any early screening assay(s) to identify and eliminate pharmaceuticals with the potential to cause severe liver injury in humans would be of economic value as well. The present review discusses the background, proof-of-concept, and validation studies associated with high-content screening (HCS) by two major pharmaceutical companies (Pfizer Inc and Jansen Pharmaceutical Companies of Johnson & Johnson) for detecting compounds with the potential to cause human DILI. These HCS assays use fluorescent-based markers of cell injury in either human hepatocytes or HepG2 cells. In collaboration with Evotec, an independent contract lab, these two companies also independently evaluated larval zebrafish as an early-stage in vivo screen for hepatotoxicity in independently conducted, blinded assessments. Details about this model species, the need for bioanalysis, and, specifically, the outcome of the phenotypic-based zebrafish screens are presented. Comparing outcomes in zebrafish against both HCS assays suggests an enhanced detection for hepatotoxicants of most DILI concern when used in combination with each other, based on the U.S. Food and Drug Administration DILI classification list.

Placebo-controlled trial of oral laquinimod for multiple sclerosis

BACKGROUND

Two proof-of-concept clinical trials have provided evidence that laquinimod reduces disease activity in patients with relapsing-remitting multiple sclerosis.

METHODS

We conducted a randomized, double-blind, phase 3 study at 139 sites in 24 countries. A total of 1106 patients with relapsing-remitting multiple sclerosis were randomly assigned in a 1:1 ratio to receive oral laquinimod at a dose of 0.6 mg once daily or placebo for 24 months. The primary end point was the annualized relapse rate during the 24-month period. Secondary end points included confirmed disability progression (defined as an increase in the score on the Expanded Disability Status Scale that was sustained for at least 3 months) and the cumulative number of gadolinium-enhancing lesions and new or enlarging lesions on T(2)-weighted magnetic resonance imaging.

RESULTS

Treatment with laquinimod as compared with placebo was associated with a modest reduction in the mean (±SE) annualized relapse rate (0.30±0.02 vs. 0.39±0.03, P=0.002) and with a reduction in the risk of confirmed disability progression (11.1% vs. 15.7%; hazard ratio, 0.64; 95% confidence interval, 0.45 to 0.91; P=0.01). The mean cumulative numbers of gadolinium-enhancing lesions and new or enlarging lesions on T(2)-weighted images were lower for patients receiving laquinimod than for those receiving placebo (1.33±0.14 vs. 2.12±0.22 and 5.03±0.08 vs. 7.14±0.07, respectively; P<0.001 for both comparisons). Transient elevations in alanine aminotransferase levels to greater than three times the upper limit of the normal range were observed in 24 patients receiving laquinimod (5%) and 8 receiving placebo (2%).

CONCLUSIONS

In this phase 3 study, oral laquinimod administered once daily slowed the progression of disability and reduced the rate of relapse in patients with relapsing-remitting multiple sclerosis. (Funded by Teva Pharmaceutical Industries; ClinicalTrials.gov number, NCT00509145.).

Recurrent drug-induced liver injury (DILI) with different drugs in the Spanish Registry: the dilemma of the relationship to autoimmune hepatitis

BACKGROUND & AIMS

Multiple instances of DILI in the same patient with drugs of similar structure or function as well as completely unrelated drugs are not well understood and poorly documented. We have sought evidence of the frequency and characteristics of patients who have experienced two DILI episodes due to different drugs.

METHODS

All cases of DILI systematically collected in the Spanish DILI Registry between 1994 and 2009 were retrieved. Data on demographics, clinical, laboratory and pathological findings, and outcome were analyzed.

RESULTS

Nine patients (mean age 67 years, four women) out of 742, 1.21%, had evidence of two DILI episodes caused by different drugs. In four cases DILI was associated with structurally related drugs and in an additional two cases the drugs had a common target. In another case, unrelated antibiotics were implicated. In only two cases, the two drugs/herbals were not related in structure or function. All but one patient exhibited hepatocellular damage. The type of damage was consistent in both DILI episodes. Four cases presented as autoimmune hepatitis (AIH) in the second episode.

CONCLUSIONS

Multiple episodes of DILI in association with different drugs occur infrequently. In each individual, the type of injury was similar during the two DILI episodes, regardless of the causative drug. Second episodes of DILI are more likely to be associated with features of AIH. It remains uncertain if this is drug-induced unmasking of true AIH or DILI with autoimmune features. These cases illustrate the dilemma faced by clinicians in distinguishing these possibilities.

Continuous reporting of new cases in Spain supports the relationship between Herbalife® products and liver injury

PURPOSE

Previous publications have linked Herbalife® products to hepatotoxicity. The identification of earlier cases in which the culprit agent could not be established raised the hypothesis of a possible contamination of some specific batches of Herbalife products.

METHODS

We searched the Spanish Pharmacovigilance Centres' database of adverse reactions for reports of liver injury associated with the use of Herbalife products from 2003, when the first case was submitted, through September 2010.

RESULTS

The search resulted in 20 reports of liver damage (mean age, 49 years; 16 women), with 12 patients (60%) requiring hospitalization. Hepatocellular damage predominated, and nine (53%) of the hepatocellular cases with bilirubin values were jaundiced, fulfilling the Hy's law criteria, which increases the risk for serious outcomes. Two patients experienced a positive rechallenge. One patient developed cirrhosis, whereas all the others recovered. Causality assessment by the Karch and Lasagna modified algorithm showed a category of definite in 1 case, probable in 14, and possible in 5. Analysis of the different Herbalife products that each patient had taken did not enable us to identify any commonly known hepatotoxic ingredient.

CONCLUSIONS

Our results support the relationship between the consumption of Herbalife products and hepatotoxicity, underscore the concern regarding the liver-related safety of this dietary supplement, and emphasize the need to establish further regulatory measures.

FDA-approved drug labeling for the study of drug-induced liver injury

Drug-induced liver injury (DILI) is a leading cause of drugs failing during clinical trials and being withdrawn from the market. Comparative analysis of drugs based on their DILI potential is an effective approach to discover key DILI mechanisms and risk factors. However, assessing the DILI potential of a drug is a challenge with no existing consensus methods. We proposed a systematic classification scheme using FDA-approved drug labeling to assess the DILI potential of drugs, which yielded a benchmark dataset with 287 drugs representing a wide range of therapeutic categories and daily dosage amounts. The method is transparent and reproducible with a potential to serve as a common practice to study the DILI of marketed drugs for supporting drug discovery and biomarker development.

Drug-induced autoimmune-like hepatitis

The clinical phenotype of classical autoimmune hepatitis can be mimicked by idiosyncratic drug-induced liver injury, and differentiation can be difficult. The goals of this review are to enumerate the major agents of drug-induced autoimmune-like hepatitis, describe the clinical findings and risk factors associated with it, detail the clinical tools by which to assess causality, discuss putative pathogenic mechanisms, and describe treatment and outcome. The frequency of drug-induced autoimmune-like hepatitis among patients with classical features of autoimmune hepatitis is 9%. Minocycline and nitrofurantoin are implicated in 90% of cases. Female predominance, acute onset, and absence of cirrhosis at presentation are important clinical manifestations. Genetic factors affecting phase I and phase II transformations of the drug, polymorphisms that protect against cellular oxidative stress, and human leukocyte antigens that modulate the immune response may be important pathogenic components. Clinical judgment is the mainstay of diagnosis as structured diagnostic methods for drug-induced liver injury are imperfect. The covalent binding of a reactive drug metabolite to a hepatocyte surface protein (commonly a phase I or phase II enzyme), formation of a neoantigen, activation of CD8 T lymphocytes with nonselective antigen receptors, and deficient immune regulatory mechanisms are the main bases for a transient loss of self-tolerance. Discontinuation of the offending drug is the essential treatment. Spontaneous improvement usually ensues within 1 month. Corticosteroid therapy is warranted for symptomatic severe disease, and it is almost invariably effective. Relapse after corticosteroid withdrawal probably does not occur, and its absence distinguishes drug-induced disease from classical autoimmune hepatitis.

Mechanisms of drug-induced liver injury: from bedside to bench

The low incidence of idiosyncratic drug-induced liver injury (DILI), together with the lack of a reliable diagnostic biomarker and robust preclinical and in vitro toxicology test systems for the condition have limited our ability to define the mechanisms of DILI. A notable exception is acetaminophen hepatotoxicity, which is associated with the formation of a well-characterized and highly reactive intermediate metabolite, N-acetyl-p-benzoquinone imine. However, studies have also suggested a role for the host immune response and variation in the expression of the lymphocyte CD44 gene in the pathogenesis of acetaminophen hepatotoxicity. A careful review of the laboratory, clinical and histological phenotype of patients with DILI can provide potential clues to the mechanisms of disease pathogenesis, as observed with fialuridine and valproate hepatotoxicity. In addition, the use of transcriptomic and genomic approaches in patients with well-characterized DILI has provided important insights into the involvement of the host immune response in the pathogenesis of hepatotoxicity associated with the administration of flucloxacillin, lumiracoxib or ximelagatran. This Review highlights new developments regarding the potential role of reactive metabolites, mitochondrial toxicity, host immune-response pathways and biliary transporters in the etiopathogenesis of DILI. Going forward, a bedside-to-bench approach could improve our understanding of the mechanisms and risk factors for DILI.

Hepatic safety and tolerability in the maraviroc clinical development program

Maraviroc is the first CCR5 antagonist to be approved for the treatment of HIV-1 infection. It is generally well tolerated, with a similar side-effect profile to placebo in controlled studies. Many agents used to treat HIV disease are associated with the potential for hepatotoxicity. The hepatic effects of maraviroc were analyzed across all Pfizer-sponsored maraviroc clinical trials, in which 2350 volunteers received maraviroc. Although sporadic hepatic enzyme abnormalities were reported in 34 phase 1/2a studies of up to 28-day duration, they demonstrated no dose relationship or association with hyperbilirubinemia. In the four phase 2b/3 studies in antiretroviral -naive and antiretroviral-experienced patients, there was no significant imbalance in hepatic enzyme abnormalities or hepatobiliary adverse events in maraviroc versus comparator arms up to week 96. The findings were similar in patients coinfected with hepatitis B and/or C virus, although the number of coinfected patients was small. No patient met the strict definition for Hy's Law. Two participants reported severe hepatotoxicity and although other potential causes were present, the contribution of maraviroc to these events could not be excluded. This analysis suggests that maraviroc does not present significant risks to hepatic safety when taken at the recommended doses in the populations studied.

Single-center experience with drug-induced liver injury from India: causes, outcome, prognosis, and predictors of mortality

OBJECTIVES

Although drug-induced liver injury (DILI) is rare, it may result in significant morbidity or death. The causes and outcome vary according to regions, with acetaminophen and complementary medicines common in the West and the Far East, respectively. This study evaluates the causes, outcomes, predictors, and models for 90-day mortality from DILI from India.

METHODS

Consecutive patients with DILI from 1997 to 2008 based on International Consensus Criteria from a medical college hospital setting were studied.

RESULTS

Of the 313 patients, 58% were males. Leading causes were a combination of four anti-tuberculous drugs (ATDs) (58%), anti-epileptics (11%), olanzapine (5.4%), and dapsone (5.4%). The overall 90-day mortality of 17.3% was significantly higher for ATD hepatitis (21.5%) vs. those without (11.4%) (P=0.02). The highest mortality was for leflunomide (75%). Seventy-eight percent of patients received more than one drug. Fulminant hepatic failure developed more commonly in females than in males (23% vs. 17%). Of the 66% of cases with jaundice and/or icterus, mortality was 26%. Multivariable models for mortality using a combination of encephalopathy, ascites, and bilirubin, or a combination of albumin, prothrombin time, and white blood cell count yielded a C-statistic of at least 0.86 by recursive partitioning and 0.92 by logistic regression. Model for end stage liver disease (MELD) scores of 38 and 46 yield probabilities of death of 0.90 (confidence interval (CI): 0.71-0.97) and 0.99 (CI: 0.90-1.00), respectively.

CONCLUSIONS

DILI results in significant overall mortality (17.3%). ATDs, anti-convulsants, sulphonamides, and olanzapine are the leading causes of DILI. Although common in males, more females developed fulminant hepatic failure. High-MELD score or a combination of ascites, encephalopathy, high bilirubin, prothrombin time, and leukocyte count are predictive of mortality.

Standardization of nomenclature and causality assessment in drug-induced liver injury: summary of a clinical research workshop

Idiosyncratic drug-induced liver injury (DILI) is an important but relatively infrequent cause of potentially severe acute and chronic liver injury. The aim of this clinical research workshop was to review and attempt to standardize the current nomenclature and terminology used in DILI research. Because DILI is a diagnosis of exclusion, selected elements of the medical history, laboratory tests, and previous reports were proposed to improve causality assessment. Definitions and diagnostic criteria regarding the onset of DILI, evolution of liver injury, risk factors, and mandatory testing versus optional testing for competing causes were reviewed. In addition, the role of intentional and inadvertent rechallenge, liver histology, and host genetic polymorphisms in establishing the diagnosis and prognosis of DILI were reviewed. Consensus was established regarding the need to develop a web-of-knowledge database that provides concise, reliable, and updated information on cases of liver injury due to drugs and herbal and dietary supplements. In addition, the need to develop drug-specific computerized causality assessment methods that are derived from prospectively phenotyped cases was a high priority. Proposed scales for grading DILI severity and assessing the likelihood of an agent causing DILI and written criteria for improving the reliability, accuracy, and reproducibility of expert opinion were reviewed. Finally, the unique challenges of assessing causality in children, patients with underlying liver disease, and subjects taking herbal and dietary supplements were discussed.

CONCLUSION

Workshop participants concluded that multicenter referral networks enrolling patients with suspected DILI according to standardized methodologies are needed. These networks should also collect biological samples that may provide crucial insights into the mechanism(s) of DILI with the ultimate aim of preventing future cases of DILI.

A genome-wide study identifies HLA alleles associated with lumiracoxib-related liver injury

Lumiracoxib is a selective cyclooxygenase-2 inhibitor developed for the symptomatic treatment of osteoarthritis and acute pain. Concerns over hepatotoxicity have contributed to the withdrawal or non-approval of lumiracoxib in most major drug markets worldwide. We performed a case-control genome-wide association study on 41 lumiracoxib-treated patients with liver injury (cases) and 176 matched lumiracoxib-treated patients without liver injury (controls). Several SNPs from the MHC class II region showed strong evidence of association (the top SNP was rs9270986 with P = 2.8 x 10(-10)). These findings were replicated in an independent set of 98 lumiracoxib-treated cases and 405 matched lumiracoxib-treated controls (top SNP rs3129900, P = 4.4 x 10(-12)). Fine mapping identified a strong association to a common HLA haplotype (HLA-DRB1*1501-HLA-DQB1*0602-HLA-DRB5*0101-HLA-DQA1*0102, most significant allele P = 6.8 x 10(-25), allelic odds ratio = 5.0, 95% CI 3.6-7.0). These results offer the potential to improve the safety profile of lumiracoxib by identifying individuals at elevated risk for liver injury and excluding them from lumiracoxib treatment.

Trabectedin Plus Pegylated Liposomal Doxorubicin in Recurrent Ovarian Cancer

Purpose

The objective of this study was to compare the efficacy and safety of trabectedin plus pegylated liposomal doxorubicin (PLD) with that of PLD alone in women with recurrent ovarian cancer after failure of first-line, platinum-based chemotherapy.

Patients and Methods

Women ≥ 18 years, stratified by performance status (0 to 1 v 2) and platinum sensitivity, were randomly assigned to receive an intravenous infusion of PLD 30 mg/m2followed by a 3-hour infusion of trabectedin 1.1 mg/m2every 3 weeks or PLD 50 mg/m2every 4 weeks. The primary end point was progression-free survival (PFS) by independent radiology assessment.

Results

Patients (N = 672) were randomly assigned to trabectedin/PLD (n = 337) or PLD (n = 335). Median PFS was 7.3 months with trabectedin/PLD v 5.8 months with PLD (hazard ratio, 0.79; 95% CI, 0.65 to 0.96; P = .0190). For platinum-sensitive patients, median PFS was 9.2 months v 7.5 months, respectively (hazard ratio, 0.73; 95% CI, 0.56 to 0.95; P = .0170). Overall response rate (ORR) was 27.6% for trabectedin/PLD v 18.8% for PLD (P = .0080); for platinum-sensitive patients, it was 35.3% v 22.6% (P = .0042), respectively. ORR, PFS, and overall survival among platinum-resistant patients were not statistically different. Neutropenia was more common with trabectedin/PLD. Grade 3 to 4 transaminase elevations were also more common with the combination but were transient and noncumulative. Hand-foot syndrome and mucositis were less frequent with trabectedin/PLD than with PLD alone.

Conclusion

When combined with PLD, trabectedin improves PFS and ORR over PLD alone with acceptable tolerance in the second-line treatment of recurrent ovarian cancer.

CCR5 antagonists: host-targeted antiviral agents for the treatment of HIV infection, 4 years on

The chemokine coreceptor 5 (CCR5) antagonists are antiretroviral agents with an extracellular, host-targeted mechanism of action against HIV. Maraviroc, the first-in-class CCR5 antagonist, received regulatory approval in 2007, becoming the first oral antiretroviral from a new class in more than 10 years. Other compounds in this class are in various stages of clinical development. In 2005, we reviewed the limited clinical data then available on CCR5 antagonists. In this follow-up review, we revisit the field and assess the clinical and virological data that have emerged in the 4 years since, with particular reference to maraviroc for which the most comprehensive data currently exist.

Acetaminophen dosing of humans results in blood transcriptome and metabolome changes consistent with impaired oxidative phosphorylation

The diagnosis and management of drug-induced liver injury (DILI) is hindered by the limited utility of traditional clinical chemistries. It has recently been shown that hepatotoxicants can produce compound-specific changes in the peripheral blood (PB) transcriptome in rodents, suggesting that the blood transcriptome might provide new biomarkers of DILI. To investigate in humans, we used DNA microarrays as well as serum metabolomic methods to characterize changes in the transcriptome and metabolome in serial PB samples obtained from six healthy adults treated with a 4-g bolus dose of acetaminophen (APAP) and from three receiving placebo. Treatment did not cause liver injury as assessed by traditional liver chemistries. However, 48 hours after exposure, treated subjects showed marked down-regulation of genes involved in oxidative phosphorylation/mitochondrial function that was not observed in the placebos (P < 1.66E-19). The magnitude of down-regulation was positively correlated with the percent of APAP converted to the reactive metabolite N-acetyl-p-benzoquinone-imide (NAPQI) (r= 0.739;P= 0.058). In addition, unbiased analysis of the serum metabolome revealed an increase in serum lactate from 24 to 72 hours postdosing in the treated subjects alone (P< 0.005). Similar PB transcriptome changes were observed in human overdose patients and rats receiving toxic doses.

CONCLUSION

The single 4-g APAP dose produced a transcriptome signature in PB cells characterized by down-regulation of oxidative phosphorylation genes accompanied by increased serum lactate. Similar gene expression changes were observed in rats and several patients after consuming hepatotoxic doses of APAP. The timing of the changes and the correlation with NAPQI production are consistent with mechanisms known to underlie APAP hepatoxicity. These studies support the further exploration of the blood transcriptome for biomarkers of DILI.

Impact of biomarker development on drug safety assessment

Drug safety has always been a key aspect of drug development. Recently, the Vioxx case and several cases of serious adverse events being linked to high-profile products have increased the importance of drug safety, especially in the eyes of drug development companies and global regulatory agencies. Safety biomarkers are increasingly being seen as helping to provide the clarity, predictability, and certainty needed to gain confidence in decision making: early-stage projects can be stopped quicker, late-stage projects become less risky. Public and private organizations are investing heavily in terms of time, money and manpower on safety biomarker development. An illustrative and "door opening" safety biomarker success story is the recent recognition of kidney safety biomarkers for pre-clinical and limited translational contexts by FDA and EMEA. This milestone achieved for kidney biomarkers and the "know how" acquired is being transferred to other organ toxicities, namely liver, heart, vascular system. New technologies and molecular-based approaches, i.e., molecular pathology as a complement to the classical toolbox, allow promising discoveries in the safety biomarker field. This review will focus on the utility and use of safety biomarkers all along drug development, highlighting the present gaps and opportunities identified in organ toxicity monitoring. A last part will be dedicated to safety biomarker development in general, from identification to diagnostic tests, using the kidney safety biomarkers success as an illustrative example.

Liver safety in patients with type 2 diabetes treated with pioglitazone: results from a 3-year, randomized, comparator-controlled study in the US

BACKGROUND/AIMS

Non-alcoholic fatty liver disease (NAFLD), the major hepatic manifestation of type 2 diabetes mellitus, is the most common liver disease in the US. Thiazolidinediones, a commonly used drug class for the treatment of type 2 diabetes, have emerged as a potentially useful treatment for NAFLD. There are, however, lingering concerns about their potential toxicity as well as emerging concerns about how to monitor for and assess hepatotoxicity. We conducted a randomized, long-term, double-blind, hepatic safety study at 171 centres in the US in which 2097 patients with type 2 diabetes received either pioglitazone or glibenclamide (glyburide).

METHODS

Patients were randomized to receive either pioglitazone (15-45 mg once daily) or glibenclamide (5-15 mg once daily) for 3 years. The primary objective was to evaluate drug-induced liver injury manifested by liver enzyme elevations, measured every 8 weeks for the first year and every 12 weeks thereafter. The primary endpoint was a confirmed ALT greater than three times the upper limit of normal (>3 x ULN) with a secondary endpoint of 8 x ULN.

MAIN RESULTS

The intent-to-treat population included 1051 pioglitazone-treated and 1046 glibenclamide-treated patients; of these, 411 pioglitazone patients and 413 glibenclamide patients completed the study. The incidence of hepatocellular injury was 0 with pioglitazone and 4 (0.38%) with glibenclamide (p = 0.0617). Analyses of the secondary endpoints revealed no ALT >8 x ULN for pioglitazone versus 1 with glibenclamide (p = 0.4988); no ALT >3 x ULN + total bilirubin 2 x ULN with pioglitazone versus 1 with glibenclamide (p = 0.4988); and fewer ALT >3 x ULN single elevations with pioglitazone (n = 3) than with glibenclamide (n = 9; p = 0.0907). Significantly (p < or = 0.05) fewer cases of ALT >1.5 x ULN, aspartate aminotransferase >1.5 x ULN and gamma-glutamyl transpeptidase >1.5 x ULN were seen with pioglitazone compared with glibenclamide. No case of hepatic dysfunction or hepatic failure was reported in either treatment group; two cases of hepatic cirrhosis with glibenclamide were reported.

CONCLUSION

This study demonstrates an hepatic safety profile of pioglitazone similar to that of glibenclamide in long-term use in patients with poorly controlled type 2 diabetes. Trial registration number (clinicaltrials.gov): NCT00494312.

Unintended hepatic adverse events associated with cancer chemotherapy

Chemotherapy is meant to be toxic, but it is particularly aimed at the tumor cells. Collateral damage may occur to normal cells and tissues, especially if they are fairly rapidly regenerating, as is the case for bone marrow cells, intestinal epithelial cells, and liver cells after hepatic injury. The liver has a great capacity to resist injury, overcome it, and to regenerate, even after quite massive injury (resection of 50%-65%, for example). This capacity may make it susceptible to chemotherapeutic toxicity, and a struggle between injury and adaptation, leading to recovery and tolerance or to failure and death. If the chemotherapy is aimed just at delaying progression of the cancer for a few weeks or months, it may not be worth the risk of irreversible liver injury developing in that time. Close clinical observation and sound clinical judgment are required.

Drug-induced liver injury: what was new in 2008?

BACKGROUND

Given the number of publications appearing annually regarding drug-induced liver injury (DILI), there remains a need to concisely summarize each year's new crop of case series and reports as well as the advances in mechanisms of liver injury and in the field of pharmacogenomics relating to DILI.

OBJECTIVE

To present an up-to-date review of the past year's most important clinical studies and reports of DILI, placing them into context of previous publications.

METHODS

A Medline search was conducted of all manuscripts appearing in the fields "hepatotoxicity" and "drug-induced liver injury" during the calendar year 2008. The most clinically relevant English language case reports and studies exploring mechanisms and risk factors for DILI were then chosen for review, and supplemented with older literature where appropriate.

CONCLUSIONS

As in past years, 2008 was replete with publications dealing with virtually all facets of DILI, including updated incidence and prevalence data, as well as the latest information regarding mechanisms of liver injury. Data from the first 300 patients in the National Institute of Health-sponsored DILI Network registry of > 100 non-acetaminophen causes were presented. Antimicrobials and CNS drugs were responsible for > 60% of cases, with herbals and dietary supplements being increasingly reported. Identification of genetic predispositions to DILI is coming of age with the FDA calling for the testing of human leukocyte antigen B(*)5701 before the use of abacavir to reduce the risk of hypersensitivity reactions. Several groups emphasized the pitfalls in utilizing Roussel Uclaf Causality Assessment Method and other causality assessment methodologies, and an updated review appeared on the use of potentially hepatotoxic medications in patients with underlying liver disease.

Detecting outliers in multivariate laboratory data

Laboratory data collected in clinical trials often include outliers, and these are often the observations of most interest. In high dimensional settings, outliers can be difficult to detect and can be masked by classical statistical methods. A method of plotting robustly scaled data in such a way as to expose outliers is described and an application is presented.

The future of drug safety testing: expanding the view and narrowing the focus

Drug safety remains a high profile issue at a time when the cost and time required to develop a new drug are at an all time high. Balancing risk against the expected clinical benefit is the primary purpose of preclinical and clinical testing. We offer an expanded view on the application of predictive strategies and technologies to early safety decisions and suggestions to narrow the focus for improving preclinical safety testing to the problems that contribute most to adverse drug reactions.