Anticholestatic effects of bezafibrate in patients with primary biliary cirrhosis treated with ursodeoxycholic acid

New paradigms in the treatment of hepatic cholestasis: from UDCA to FXR, PXR and beyond

Cholestasis is an impairment of bile formation/flow at the level of the hepatocyte and/or cholangiocyte. The first, and for the moment, most established medical treatment is the natural bile acid (BA) ursodeoxycholic acid (UDCA). This secretagogue improves, e.g. in intrahepatic cholestasis of pregnancy or early stage primary biliary cirrhosis, impaired hepatocellular and cholangiocellular bile formation mainly by complex post-transcriptional mechanisms. The limited efficacy of UDCA in various cholestatic conditions urges for development of novel therapeutic approaches. These include nuclear and membrane receptor agonists and BA derivatives. The nuclear receptors farnesoid X receptor (FXR), retinoid X receptor (RXR), peroxisome proliferator-activated receptor α (PPARα), and pregnane X receptor (PXR) are transcriptional modifiers of bile formation and at present are under investigation as promising targets for therapeutic interventions in cholestatic disorders. The membrane receptors fibroblast growth factor receptor 4 (FGFR4) and apical sodium BA transporter (ASBT) deserve attention as additional therapeutic targets, as does the potential therapeutic agent norUDCA, a 23-C homologue of UDCA. Here, we provide an overview on established and future promising therapeutic agents and their potential molecular mechanisms and sites of action in cholestatic diseases.

A prospective randomized controlled study of long-term combination therapy using ursodeoxycholic acid and bezafibrate in patients with primary biliary cirrhosis and dyslipidemia

OBJECTIVES

The aim of this study was to assess the long-term prognosis, efficacy, and safety of combination therapy using ursodeoxycholic acid (UDCA) and bezafibrate (BF) for primary biliary cirrhosis (PBC) patients exhibiting dyslipidemia.

METHODS

We performed a prospective, randomized, controlled, multicenter study to compare the long-term clinical results between combination therapy and UDCA monotherapy for patients refractory to UDCA monotherapy. Twenty-seven consecutive PBC patients were enrolled.

RESULTS

The median treatment period in the UDCA and UDCA+BF groups was 107 and 110 months, respectively. The serum alkaline phosphatase (ALP) levels and the Mayo risk score in the combination therapy group (mean 290 IU/l and 0.91, respectively) were significantly lower than those in the UDCA monotherapy group (mean 461 IU/l and 1.42, respectively) at 8 years after the beginning of the study (P<0.05). The serum creatinine levels in the combination therapy group (mean 0.94 mg/dl) were significantly higher than those in the UDCA monotherapy group (mean 0.56 mg/dl) at 8 years after the beginning of the study (P<0.05). However, the survival rate was not significantly different between the groups. We observed dose reduction or discontinuation of the administration of BF, but not UDCA, due to renal dysfunction or muscle pain.

CONCLUSIONS

Long-term combination therapy significantly improved the serum ALP levels and the Mayo risk score. However, the survival rate was not significantly different between the groups. In addition, long-term combination therapy significantly increased the serum creatinine levels. We should pay close attention to adverse events during this long-term combination therapy.

Combination therapy of bezafibrate and ursodeoxycholic acid for primary biliary cirrhosis: A meta-analysis

The aim of this study was to assess the efficiency and safety of combination therapy of ursodeoxycholic acid (UDCA) and bezafibrate for primary biliary cirrhosis. A meta-analysis of all long-term randomized controlled trials comparing the combination of UDCA and bezafibrate with UDCA monotherapy was performed via electronic searches. Seven trials, which included 177 patients, were assessed. Combination therapy with UDCA and bezafibrate was more effective than UDCA monotherapy in improving liver biochemistry, alkaline phosphatase (mean difference [MD], -146.15 IU/L; 95% confidence interval [CI], -193.58 to -98.72; P < 0.00001), γ-glutamyltransferase (MD, -20.64 IU/L; 95% CI, -30.86 to -10.43; P < 0.0001), immunoglobulin M (MD, -90.96 mg/dL; 95% CI, -137.36 to -44.56; P = 0.0001) and triglycerides (MD, -15.49 mg/dL; 95% CI, -30.25 to -0.74; P = 0.04). However, their effects on pruritus (odds ratio [OR], 0.82; 95% CI, 0.30-2.24; P = 0.70) and alanine aminotransferase (MD, -8.41 IU/L; 95% CI, -22.57 to 5.75; P = 0.24) did not differ significantly. This meta-analysis revealed no significant differences in the incidence of all-cause mortality (OR, 0.72; 95% CI, 0.10-5.49; P = 0.75) and adverse events (OR, 0.35; 95% CI, 0.07-1.84; P = 0.22) between patients treated with combination therapy and those treated with monotherapy. In this meta-analysis, combination therapy with UDCA and bezafibrate was more effective than UDCA monotherapy. Combination therapy improved liver biochemistry, but did not improve clinical symptoms, incidence of death or adverse events more effectively than monotherapy.

Advances in pharmacotherapy for primary biliary cirrhosis

INTRODUCTION

Primary biliary cirrhosis (PBC) is a chronic autoimmune liver disease mostly seen in middle-aged women characterized by progressive nonsuppurative destruction of small bile ducts resulting in intrahepatic cholestasis, parenchymal injury and ultimately end-stage liver disease. Despite major breakthroughs in our understanding of PBC, there remains only one FDA-approved agent for treatment: ursodeoxycholic acid (UDCA) to which one-third of patients are unresponsive.

AREAS COVERED

Biochemical response to treatment with UDCA is associated with excellent survival rates in PBC patients. However, there is a need for alternative treatments for nonresponders. Results from human epidemiological and genetic studies as well as preclinical studies in PBC animal models have provided a strong impetus for the development of new therapeutic agents. In this review, we discuss the recent advances in translational research in PBC focusing on promising therapeutic approaches, namely immune-based targeted therapies and agents targeting the synthesis and circulation of bile acids.

EXPERT OPINION

We are in a new era for the development of novel therapies for PBC. Data on fibrates, budesonide and obeticholic acid offer encouragement for nonresponders to UDCA.

Progress in treatment of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic autoimmune cholestatic liver disease characterized by cholestasis, and it often eventually develops into cirrhosis, portal hypertension and liver failure. Asymptomatic patients typically are diagnosed by the elevation of alkaline phosphatase (ALP) and the presence of anti-mitochondrial antibody (AMA) titers of 1:40 or greater. Ursodeoxycholic acid (UDCA) is the only Food and Drug Administration approved treatment for PBC, but it is not universally effective. In patients with UDCA-refractory PBC, additional therapies should be considered, including budesonide, fibrates, obeticholic acid, immunosuppressants and liver transplantation.

New insights in the biology of ABC transporters ABCC2 and ABCC3: impact on drug disposition

INTRODUCTION

For the elimination of environmental chemicals and metabolic waste products, the body is equipped with a range of broad specificity transporters that are present in excretory organs as well as in several epithelial blood-tissue barriers.

AREAS COVERED

ABCC2 and ABCC3 (also known as MRP2 and MRP3) mediate the transport of various conjugated organic anions, including many drugs, toxicants and endogenous compounds. This review focuses on the physiology of these transporters, their roles in drug disposition and how they affect drug sensitivity and toxicity. It also examines how ABCC2 and ABCC3 are coordinately regulated at the transcriptional level by members of the nuclear receptor (NR) family of ligand-modulated transcription factors and how this can be therapeutically exploited.

EXPERT OPINION

Mutations in both ABCC2 and ABCC3 have been associated with changes in drug disposition, sensitivity and toxicity. A defect in ABCC2 is associated with Dubin-Johnson syndrome, a recessively inherited disorder characterized by conjugated hyperbilirubinemia. Pharmacological manipulation of the activity of these transporters can potentially improve the pharmacokinetics and thus therapeutic activity of substrate drugs but also affect the physiological function of these transporters and consequently ameliorate associated disease states.

Progress in pharmaceutical therapy of autoimmune liver diseases

Autoimmune liver diseases (AILDs) include autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and overlap syndrome (OS). AILDs are the new research hotspot in the field of liver diseases nowadays. The advances in research of AILDs have led to a new understanding of pharmaceutical treatment of this disease. This article reviews the progress in the pharmaceutical therapy of AILDs.

PPARα: A Master Regulator of Bilirubin Homeostasis

Hypolipidemic fibrates activate the peroxisome proliferator-activated receptor (PPAR) α to modulate lipid oxidation and metabolism. The present study aimed at evaluating how 3 PPARα agonists, namely, fenofibrate, gemfibrozil, and Wy14,643, affect bilirubin synthesis and metabolism. Human umbilical vein epithelial cells (HUVEC) and coronary artery smooth muscle cells (CASMC) were cultured in the absence or presence of the 3 activators, and mRNA, protein, and/or activity levels of the bilirubin synthesizing heme oxygenase- (HO-) 1 and biliverdin reductase (BVR) enzymes were determined. Human hepatocytes (HH) and HepG2 cells sustained similar treatments, except that the expression of the bilirubin conjugating UDP-glucuronosyltransferase (UGT) 1A1 enzyme and multidrug resistance-associated protein (MRP) 2 transporter was analyzed. In HUVECs, gemfibrozil, fenofibrate, and Wy14,643 upregulated HO-1 mRNA expression without affecting BVR. Wy14,643 and fenofibrate also caused HO-1 protein accumulation, while gemfibrozil and fenofibrate favored the secretion of bilirubin in cell media. Similar positive regulations were also observed with the 3 PPARα ligands in CASMCs where HO-1 mRNA and protein levels were increased. In HH and HepG2 cells, both UGT1A1 and MRP2 transcripts were also accumulating. These observations indicate that PPARα ligands activate bilirubin synthesis in vascular cells and metabolism in liver cells. The clinical implications of these regulatory events are discussed.

Evidence-based treatment of primary biliary cirrhosis

The natural history of primary biliary cirrhosis (PBC) has improved greatly during the past two decades because of its diagnosis at earlier stages and the widespread use of ursodeoxycholic acid as first-line treatment. As a result, far fewer patients require liver transplantation and patients diagnosed with early-stage disease appear to have a normal life expectancy. The evidence-based treatment of PBC is reviewed here. The challenge of designing and executing high-quality clinical trials as well as lessons from past clinical trials are discussed. The rationales for the use of budesonide and new investigational therapies (PPAR and FXR agonists) as well as their therapeutic potential in light of recent available data are also reviewed. An algorithm of the management of PBC patients responding or not to ursodeoxycholic acid is proposed.

Recent advances in diagnosis and treatment of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic autoimmune liver disease characterized by the destruction of small intrahepatic bile ducts and the presence of highly specific serum antimitochondrial antibodies (AMAs). In this article, we will review the clinical, serological and histopathological features of PBC as well as the advances in the diagnosis and differential diagnosis of PBC. In addition, this article systematically describes the advances in the treatment of PBC, and the treatments include ursodeoxycholic acid (UDCA), budesonide, methotrexate (MTX), farnesoid X receptor (FXR) agonists, cyclosporine A, bezafibrate, rituximab, bone marrow-derived mesenchymal stem cell (BM-MSC) transplantation, and liver transplantation. At present, liver transplantation is the only option with known therapeutic benefit for end-stage PBC patients.

Clinical application of transcriptional activators of bile salt transporters

Hepatobiliary bile salt (BS) transporters are critical determinants of BS homeostasis controlling intracellular concentrations of BSs and their enterohepatic circulation. Genetic or acquired dysfunction of specific transport systems causes intrahepatic and systemic retention of potentially cytotoxic BSs, which, in high concentrations, may disturb integrity of cell membranes and subcellular organelles resulting in cell death, inflammation and fibrosis. Transcriptional regulation of canalicular BS efflux through bile salt export pump (BSEP), basolateral elimination through organic solute transporters alpha and beta (OSTα/OSTβ) as well as inhibition of hepatocellular BS uptake through basolateral Na(+)-taurocholate cotransporting polypeptide (NTCP) represent critical steps in protection from hepatocellular BS overload and can be targeted therapeutically. In this article, we review the potential clinical implications of the major BS transporters BSEP, OSTα/OSTβ and NTCP in the pathogenesis of hereditary and acquired cholestatic syndromes, provide an overview on transcriptional control of these transporters by the key regulatory nuclear receptors and discuss the potential therapeutic role of novel transcriptional activators of BS transporters in cholestasis.

Fibrate treatment for primary biliary cirrhosis

PURPOSE OF REVIEW

Primary biliary cirrhosis (PBC) can lead to end-stage liver disease and death. Ursodeoxycholic acid (UDCA) treatment can normalize serum liver enzymes in PBC, and such UDCA-responsive patients have a similar life expectancy as age and sex-matched controls. Nearly up to 50% of the patients with PBC, depending on sex and age at diagnosis, show an incomplete biochemical response to UDCA and require additional/alternative treatment. The purpose of this review is to critically evaluate the molecular mechanisms and clinical benefit of fibrate treatment in these patients.

RECENT FINDINGS

Fibrates have anticholestatic, anti-inflammatory, and antifibrotic effects in animal and in-vitro studies. The mechanisms that underlie these effects are complementary, and largely mediated through activation of peroxisome proliferator activated receptors. Fibrate treatment ameliorated liver biochemical tests in UDCA unresponsive patients, either as mono-therapy or in combination with UDCA. These results, however, were obtained in case series and small pilot studies. The results of phase III studies, such as the Bezafibrate in Combination With Ursodeoxycholic Acid in Primary Biliary Cirrhosis (BEZURSO) trial, are currently awaited.

SUMMARY

A considerable body of observational evidence supports the safety and efficacy of fibrate treatment in PBC patients with an incomplete response to UDCA. These results encourage the evaluation of its effects on liver-related morbidity and mortality in larger clinical trials.

Primary biliary cirrhosis in 2014

PURPOSE OF REVIEW

Primary biliary cirrhosis (PBC) was first described in the 1950s as a clinical syndrome of progressive cholestatic liver disease resulting from chronic inflammatory destruction of the intrahepatic bile ducts. In the 1980s, the autoimmune nature of the disease was appreciated with the discovery of disease-specific loss of immune tolerance to the pyruvate dehydrogenase complex and subsequent development of antimitochondrial antibodies and autoreactive T cells. Then, in the 1990s, multiple clinical trials demonstrating the efficacy of ursodiol as a treatment for PBC were published, although it has been clear that ursodiol is not a cure and only delays progression in some patients.

RECENT FINDINGS

The study of PBC in the 2000s has been buoyed by two basic science advances: rapid sequencing technologies that have led to genome wide association studies, and elucidation of the role of nuclear hormone receptors in the regulation of bile salt metabolism, which has led to novel therapies under study for cholestatic diseases.

SUMMARY

Today's clinician should be able to determine which patients with PBC are likely to progress despite treatment with ursodiol and understand the putative new bile acid and immunosuppressant treatment strategies under development, as well as be aware of the recently described genetic factors at play in the development of PBC.

Review article: controversies in the management of primary biliary cirrhosis and primary sclerosing cholangitis

BACKGROUND

Despite considerable advances over the last two decades in the molecular understanding of cholestasis and cholestatic liver disease, little improvement has been made in diagnostic tools and therapeutic strategies.

AIMS

To critically review controversial aspects of the scientific basis for common clinical practice in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) and to discuss key ongoing challenges to improve patient management.

METHODS

We performed a literature search using PubMed and by examining the reference lists of relevant review articles related to the clinical management of PBC and PSC. Articles were considered on the background of the European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD) practice guidelines and clinical experience of the authors.

RESULTS

Ongoing challenges in PBC mainly pertain to the improvement of medical therapy, particularly for patients with a suboptimal response to ursodeoxycholic acid. In PSC, development of medical therapies and sensitive screening protocols for cholangiocarcinoma represent areas of intense research. To rationally improve patient management, a better understanding of pathogenesis, including complications like pruritis and fatigue, is needed and there is a need to identify biomarker end-points for treatment effect and prognosis. Timing of liver transplantation and determining optimal regimens of immunosuppression post-liver transplantation will also benefit from better appreciation of pre-transplant disease mechanisms.

CONCLUSION

Controversies in the management of PBC and PSC relate to topics where evidence for current practice is weak and further research is needed.

Bezafibrate normalizes alkaline phosphatase in primary biliary cirrhosis patients with incomplete response to ursodeoxycholic acid

BACKGROUND & AIMS

Ursodeoxycholic acid (UDCA) is the standard treatment for primary biliary cirrhosis (PBC) but excellent response is not observed in all cases. Since potential favourable effects of fibrates have been reported in short series with inconclusive results, we have carried out a pilot study to analyse the effects of bezafibrate in patients with suboptimal response to UDCA.

METHODS

Thirty women (age 52.3 ± 2.3 years) treated with UDCA and abnormal alkaline phosphatase (AP) levels received bezafibrate (400 mg/d) for 1 year. Changes were measured every 3 months during the study period of 12 months, 3 months after discontinuation and 3 months after resuming bezafibrate.

RESULTS

Two patients discontinued the treatment after few days, three at 6 and one at 9 months. Bezafibrate treatment resulted in a significant decrease in AP as early as 3 months. Normalization or decrease of AP below 1.5 times normal levels was observed in 13 and 4 patients respectively. There was also a significant decrease in γ-glutamyl transferase and alanine aminotransferase, cholesterol and triglyceride levels. Bezafibrate treatment resulted in significant improvement of pruritus. A rebound in liver biochemistries and pruritus occurred upon drug discontinuation, changes which improved again after resuming bezafibrate. Response to bezafibrate was associated with lower liver stiffness and severity of cholestasis. No severe adverse effects were observed.

CONCLUSIONS

Combination treatment of bezafibrate and UDCA is associated with marked decrease or normalization of alkaline phosphatase as early as 3 months in patients with PBC. Better biochemical response was observed in patients with early disease and lower cholestasis.

The role of canalicular ABC transporters in cholestasis

Cholestasis, a hallmark feature of hepatobiliary disease, is characterized by the retention of biliary constituents. Some of these constituents, such as bile acids, inflict damage to hepatocytes and bile duct cells. This damage may lead to inflammation, fibrosis, cirrhosis, and eventually carcinogenesis, sequelae that aggravate the underlying disease and deteriorate clinical outcome. Canalicular ATP-binding cassette (ABC) transporters, which mediate the excretion of individual bile constituents, play a key role in bile formation and cholestasis. The study of these transporters and their regulatory nuclear receptors has revolutionized our understanding of cholestatic disease. This knowledge has served as a template to develop novel treatment strategies, some of which are currently already undergoing phase III clinical trials. In this review we aim to provide an overview of the structure, function, and regulation of canalicular ABC transporters. In addition, we will focus on the role of these transporters in the pathogenesis and treatment of cholestatic bile duct and liver diseases.

Overlap of IgG4-related sclerosing cholangitis and primary biliary cirrhosis

We herein present a case of an overlap of immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) and primary biliary cirrhosis (PBC). A 61-year-old man was diagnosed with PBC due to abnormal liver biochemical tests and positivity for serum anti-M2 antibody. However, his response to bezafibrate and ursodeoxycholic acid was insufficient. Five years later, his serum IgG4 level was found to increase. His liver biopsy specimens showed features of nonsuppurative destructive cholangitis in some portal tracts and periductal fibrosis with dense infiltration of IgG4-positive cells in other portal tracts. This case demonstrates that the serum IgG4 level may be worth measuring in patients with PBC refractory to conventional treatment.

Autoimmune liver disease, autoimmunity and liver transplantation

Primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH) represent the three major autoimmune liver diseases (AILD). PBC, PSC, and AIH are all complex disorders in that they result from the effects of multiple genes in combination with as yet unidentified environmental factors. Recent genome-wide association studies have identified numerous risk loci for PBC and PSC that host genes involved in innate or acquired immune responses. These loci may provide a clue as to the immune-based pathogenesis of AILD. Moreover, many significant risk loci for PBC and PSC are also risk loci for other autoimmune disorders, such type I diabetes, multiple sclerosis and rheumatoid arthritis, suggesting a shared genetic basis and possibly similar molecular pathways for diverse autoimmune conditions. There is no curative treatment for all three disorders, and a significant number of patients eventually progress to end-stage liver disease requiring liver transplantation (LT). LT in this context has a favourable overall outcome with current patient and graft survival exceeding 80% at 5years. Indications are as for other chronic liver disease although recent data suggest that while lethargy improves after transplantation, the effect is modest and variable so lethargy alone is not an indication. In contrast, pruritus rapidly responds. Cholangiocarcinoma, except under rigorous selection criteria, excludes LT because of the high risk of recurrence. All three conditions may recur after transplantation and are associated with a greater risk of both acute cellular and chronic ductopenic rejection. It is possible that a crosstalk between alloimmune and autoimmune response perpetuate each other. An immunological response toward self- or allo-antigens is well recognised after LT in patients transplanted for non-autoimmune indications and sometimes termed "de novo autoimmune hepatitis". Whether this is part of the spectrum of rejection or an autoimmune process is not clear. In this manuscript, we review novel findings about disease processes and mechanisms that lead to autoimmunity in the liver and their possible involvement in the immune response vs. the graft after LT.

Nuclear-receptor-mediated regulation of drug- and bile-acid-transporter proteins in gut and liver

Adverse drug events (ADEs) are a common cause of patient morbidity and mortality and are classically thought to result, in part, from variation in expression and activity of hepatic enzymes of drug metabolism. It is now known that alterations in the expression of genes that encode drug- and bile-acid-transporter proteins in both the gut and liver play a previously unrecognized role in determining patient drug response and eventual clinical outcome. Four nuclear receptor (NR) superfamily members, including pregnane X receptor (PXR, NR1I2), constitutive androstane receptor (NR1I3), farnesoid X receptor (NR1H4), and vitamin D receptor (NR1I1), play pivotal roles in drug- and bile-acid-activated programs of gene expression to coordinately regulate drug- and bile-acid transport activity in the intestine and liver. This review focuses on the NR-mediated gene activation of drug and bile-acid transporters in these tissues as well as the possible underlying molecular mechanisms.

Primary biliary cirrhosis and bile acids

The dihydroxylated bile acid ursodeoxycholic acid (UDCA) has now been regarded for 20 years as the standard treatment for primary biliary cirrhosis (PBC), a chronic cholestatic immune-mediated condition marked by progressive destruction of small intrahepatic bile ducts, impaired biliary secretion, hepatocellular retention of toxic endogenous bile acids and, ultimately, the development of fibrosis leading to cirrhosis that commonly requires liver transplantation. At first sight, it seems intriguing that a bile acid could be considered for use as a therapeutic agent in a bile-acid secretion disorder. Yet, in addition to its inherently greater hydrophilic nature and competitive effect on endogenous bileacid recycling, UDCA has indeed been demonstrated to be a potent post-transcriptional secretagogue as well as a potential anti-inflammatory and anti-apoptotic agent. While the combined glucocorticoid receptor/pregnane X receptor (PXR) agonist budesonide, in combinaison with UDCA, has been shown to exert additional beneficial effects in PBC, significant progress in understanding the regulatory mechanisms involved in bile-acid homeostasis has led to the identification of nuclear [farnesoid X receptor (FXR), PXR, peroxisome proliferator-activated receptor alpha (PPARα)] and membrane (the membrane G protein-coupled bile acid receptor TGR5) receptors as critical pharmacological targets for future therapeutic approaches. Encouraging data from recent experimental and phase-II studies tend to confirm that the FXR agonist obeticholic acid and the PPARα agonists bezafibrate and fenofibrate may be used as add-on therapies in PBC patients with inadequate responses to UDCA or even as alternative first-line agents. These results could mark the beginning of a new therapeutic era for PBC.