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

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1 Alimentary Pharmacology and Therapeutics Review article: controversies in the management of primary biliary cirrhosis and primary sclerosing cholangitis T. H. Karlsen*,, M. Vesterhus*, & K. M. Boberg*,, *Norwegian PSC Research Center, Division of Cancer Medicine, Surgery and Transplantation, Oslo University Hospital, Rikshospitalet, Oslo, Norway. Department of Clinical Medicine, University of Bergen, Bergen, Norway. Department of Medicine, National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway. Institute of Clinical Medicine, University of Oslo, Oslo, Norway. Section of Gastroenterology, Division of Cancer Medicine, Surgery and Transplantation, Department of Transplantation Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway. Correspondence to: Prof. K. M. Boberg, Department of Transplantation Medicine, Division of Cancer Medicine, Surgery and Transplantation, Oslo University Hospital, Rikshospitalet, Postboks 4950 Nydalen, N-0424 Oslo, Norway. Publication data Submitted 25 September 2013 First decision 9 October 2013 Resubmitted 18 November 2013 Accepted 18 November 2013 EV Pub Online 29 December 2013 This commissioned review article was subject to full peer-review and the authors received an honorarium from Wiley, on behalf of AP&T. SUMMARY 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. Aliment Pharmacol Ther 2014; 39: doi: /apt.12581

2 Review: controversies in cholestatic diseases INTRODUCTION Cholestatic liver disease may arise due to defects at any level of bile formation. The aetiologies of these conditions range from molecular abnormities caused by genetic variation or drugs to structural changes due to developmental disorders, autoimmune bile duct injury, tumours and gallstones. In everyday clinical practice, the term is most often applied to primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Both these conditions pose major management challenges in adult hepatology. In addition to the general features associated with a broader syndrome of cholestatic liver disease (e.g. development of cholestatic liver cirrhosis) (Figure 1), disease specific pathologies (e.g. malignancy risk in PSC) require attention. Considerable advances have been made over the last two decades regarding the molecular understanding of cholestasis and cholestatic liver disease. 1 5 These advances have largely derived from the identification of the genes responsible for the progressive familial intrahepatic cholestasis (PFIC) syndromes throughout the 1990s 6 9 and from the recent genome-wide association studies (GWAS) applications in PBC and PSC. 10 Despite the new knowledge, little improvement has been made in diagnostic tools and therapeutic strategies. Primary biliary cirrhosis and PSC (Figure 2) are slowly progressive diseases with a course of one to two decades from the manifestations of early stages of disease until end-stage liver disease. This results in difficulties in establishing a robust level of evidence for the benefit of any management option, including surveillance for complications throughout the disease course. Prognostic modelling taking surrogate markers for disease stage [including alkaline phosphatase (ALP), bilirubin, model for end-stage liver disease (MELD) score, Child-Pugh score, histology and radiology] into account has, to some extent, assisted the assessment in treatment trials, but robust markers for disease activity and disease complications are missing. Interpretation of the present basis for patient management requires caution and awareness of such limitations. In this review, we aimed to critically summarise the evidence for clinical practice in PBC and PSC. The controversies that do exist arise on topics where evidence is weak or conflicting and a further and better research is needed. Therefore, we will highlight both controversies and important challenges. We will, to some extent, discuss general features of cholestatic liver disease (cirrhosis development, pruritus and fatigue) and associated Diseases Primary biliary cirrhosis (PBC) Primary sclerosing cholangitis (PSC) Biliary atresia Hereditary cholestasis Intrahepatic cholestasis of pregnancy Gallstone disease Polycystic liver disease Drug-induced liver disease Manifestation Cholestatic liver disease Other liver affection (e.g. hepatitis) Consequence Liver cirrhosis Hepatocellular cancer Bile duct cancer Pruritus Fatigue Osteoporosis Figure 1 The term cholestatic liver disease jointly denominates the manifestations of a wide variety of liver diseases. For most of the chronic cholestatic liver diseases, therapeutic opportunities are limited, resulting in progression to liver cirrhosis and risk of cancer development. Disease-associated symptoms (e.g. pruritus and fatigue) represent major clinical challenges. The focus of this review article is primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). molecular and genetic aspects. We will not provide comprehensive discussions on drug-induced cholestasis and cholestatic liver disease in the context of developmental disorders and gallstone disease, for which the interested reader is guided elsewhere METHODS A literature search was conducted 1st September 2013 on PubMed using a broad range of search terms including, but not limited to, primary biliary cirrhosis and primary sclerosing cholangitis along with ursodeoxycholic acid, treatment, clinical trial and prognostic score. Articles were selected for discussion on the basis of the authors prior knowledge on controversial or challenging topics in the management of PBC and PSC. In addition, important review articles, meta-analyses and Cochrane Systematic Reviews were reviewed and examined for relevant references and practice guidelines. Randomised clinical trials involving a treatment group (UDCA for PSC, non-udca for PSC or PBC) vs. placebo or no treatment were included for full table Aliment Pharmacol Ther 2014; 39:

3 T. H. Karlsen et al. PBC Interlobular bile duct destruction Prevalence: per Gender: F>M, 10:1 Age at onset: years Smoking increases risk >28 known risk genes Autoantibodies (AMA) Known T cell targets PBC Autoimmunity Autoimmunity Shared hepatic features: Autoimmune hepatitis (~10%) Cholestatic liver cirrhosis Pruritus Fatigue Intra-/extrahepatic bile ducts Prevalence: per Gender F<M, 1:2 Age at onset: years Smoking decreases risk >16 known risk genes Autoantibodies (ANCA?) Unknown T cell targets Cancer PSC PSC Inflammatory bowel disease Figure 2 Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) share features of an autoimmune affection targeting different levels of the biliary tree. 14, 135 Cooccurring autoimmune manifestations outside the liver are common in both conditions. In PSC, the increased risk of biliary tractand colonic cancer poses particular challenges. The present review elaborates on clinical challenges in PBC and PSC, as well as each of the shared hepatic features shown in the figure. AMA, antimitochondrial antibodies; ANCA, anti-neutrophil cytoplasmic antibodies. presentation irrespective of blinding or language. Observational studies or studies lacking a control group were excluded from full table presentation, but have been included in the main text to appropriately account for controversial aspects where appropriate. Evaluation of predictive models in PSC was limited to those assessing pre-transplant survival. Articles may have been missed by the adopted approach, and the presentation may also be biased as to the opinion of the authors. Management of PBC Diagnosis of PBC. The diagnostic criteria for PBC rely on the fact that the targets of liver infiltrating T cells and the antibody production have been identified as lipoylated domains of three members of the 2-oxo-acid dehydrogenase complex family (mainly the E2 component of the pyruvate dehydrogenase complex; PDC-E2). 14 The diagnosis can be made on the basis of two of three criteria: the presence of biochemical cholestasis (ALP elevation), detection of anti-mitochondrial antibodies (AMA) and typical histological findings. A liver biopsy is not essential in patients with ALP elevation and AMA, but may be required for the diagnosis of concurrent features of autoimmune hepatitis and disease stage. There is little controversy regarding the diagnostic criteria in PBC, but some discrepancy in the evaluation of the level of evidence supporting these. Depending on the assay employed, % of patients with PBC present without detectable AMA, even by repeated measures at follow-up. There is little knowledge on the specific pathological features of AMA-negative PBC. Other mitochondrial epitopes than M2 may be 284 Aliment Pharmacol Ther 2014; 39:

4 Review: controversies in cholestatic diseases relevant. 18 There are also slight differences in the cellular composition and severity of histological lesions between AMA-positive and -negative cases. 19 Robust genetic determinants to differentiate between AMA-positive and -negative PBC patients have not been detected; 20 however, the AMA-negative subset of patients is clearly too small to obtain conclusive statistical power in the analyses. Clinical presentation and behaviour of AMA negative PBC is largely similar to that of AMA-positive PBC, 21 and collated anecdotal data suggest that there is also a similar response to ursodeoxycholic acid. 22 Disease recurrence rates of PBC after liver transplantation also do not seem to be affected by AMA status. 23 In clinical practice, the presence of non-m2 immunoreactivity in a patient with PBC means that a liver biopsy is required for diagnosis. Typically, considerations must also be made as to the presence of small-duct PSC and genetic cholangiopathies, and precise distinctions between these conditions may not always be feasible. Current treatment of PBC. Therapeutic applications in PBC and other cholestatic liver diseases can broadly be divided into bile acid therapy and other approaches. Of bile acid preparations, doses of mg/kg/day of ursodeoxycholic acid (UDCA) appear beneficial and are commonly used in PBC AASLD advises in favour of UDCA therapy judging evidence unambiguously as class I (conditions for which there is evidence and/or general agreement that a given diagnostic evaluation, procedure or treatment is beneficial, useful and effective), level A (data derived from multiple randomised clinical trials or meta-analyses). The EASL guidelines evaluate the overall support for UDCA treatment at the same level, but suggest that the evidence for long-term treatment is less robust (category II-2; evidence for recommendation is derived from cohort or case control analytic studies, grade B; further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate, recommendation strong). This slight discrepancy may partly be due to a still ongoing dispute as to the quality of trials performed and the true efficacy of UDCA, 31 largely deriving from two negative Cochrane-based meta-analyses of survival benefit from UDCA. 32, 33 Another meta-analysis, 34 focusing on studies with long-term follow-up, however, claims a significant improvement in transplant-free survival in patients on UDCA and that duration of studies need to be taken into account when evaluating drug efficacy in PBC. UDCA therapy also appears to be associated with reduced costs compared with placebo/ conservative treatment 28, 35 and is by many authorities considered standard care. A favourable biochemical response to UDCA, incorporating specific improvements in ALP ( Barcelona criteria ), 30, 36 or in ALP, bilirubin and aspartate transaminase (AST) ( Paris criteria ), 37 seems to associate with improvement in transplant-free survival in PBC. In brief, the sum of these biochemical responses and related assessments (e.g. the Mayo risk score 38 and baseline parameters like ductopenia 39 ) strongly suggests that there is heterogeneity of the PBC patient population as to the efficacy of UDCA. The mechanism of action of UDCA is reviewed elsewhere, 40 yet which aspects of the pathogenesis of PBC that are reflected by heterogeneity in the response to UDCA are unknown. For research purposes, the response-indices may serve useful in stratifying patients in studies aiming to determine the pathophysiology of such aspects. PBC patients with little or no improvement in suggested response-indices are also candidates for trials of supplementary or alternative therapies. Future treatment of PBC. No other bile acids than UDCA are currently in use in clinical practice. Obeticholic acid, a derivative of chenodeoxycholic acid, has (unlike UDCA) strong activating effects on the nuclear receptor farnesoid X receptor (FXR) and is currently entering phase III clinical trials following promising phase II results ( NCT ). 41 A derivative of UDCA, nor-udca, is currently in phase II clinical trials for PSC (see below), but has not been tested in PBC. Of the nonbile acid therapies, bezafibrate combination therapy with UDCA has shown the most promising results 42, 43 and is also at time of writing at the recruiting stage for phase III trials ( Like obeticholic acid, bezafibrate exerts its likely main mechanism of action via nuclear receptors, targeting the pregnane X receptor (PXR; also called the steroid and xenobiotic receptor, SXR) and peroxisome proliferatoractivated receptor alpha (PPARa). 43 The glucocorticoid receptor agonist budesonide also activates PXR. 44 Budesonide has shown some efficacy, which so far has not translated into standard care, largely due to concerns on osteoporotic side effects. 49 In our opinion, glucocorticoid receptor-centred adjuvancy to UDCA in PBC should be restricted to patients with features of autoimmune hepatitis (see below). In many ways, PBC is a prototypical autoimmune disease, 14 with a well-defined autoantigen, a relatively Aliment Pharmacol Ther 2014; 39:

5 T. H. Karlsen et al. homogenous disease expression and a genetic susceptibility background similar to that of other autoimmune diseases (Figure 2). 50 For this reason, the poor efficacy of immune-targeted therapies that have been tested so far (Table 1) remains somewhat of a paradox. There is little controversy as to this observation, yet there is renewed interest in immune-target therapies on the basis of specific pathways highlighted by GWAS findings. Phase II trials on ustekinumab (a monoclonal anti-p40 antibody, are ongoing based on the prominent genetic associations with several components of the interleukin 12 (IL12) and IL23 signalling pathway in the study populations of European ancestry. 51, 52 As a note of caution in this regard, the biological implications of these genetic associations are as of yet not understood. Moreover, they seem not to be a prerequisite for PBC development as shown by the absence of similar associations in Asian study populations. 53 The efficacy of ustekinumab in other IL12/23-related diseases varies; e.g. in psoriasis, ustekinumab is part of the established treatment armamentarium, 54 whereas in multiple sclerosis, it has been concluded to be of no benefit. 55 As the relationship between this response heterogeneity and the genetic associations in implicated diseases is unknown, efficacy in PBC of ustekinumab and similar approaches is hard to predict. Adefinite controversy in PBC exists as to the possibility of an infectious aetiology. 56, 57 It is beyond the scope of this article to review the scientific basis of this dispute, which has triggered the execution of completed 58 and planned ( anti-retroviral regimens. As of yet, there is no proven benefit of such approaches. In epidemiological data (reviewed elsewhere), 59 associations have also been suggested between exposure to urinary tract pathogens (Novosphingobium aromaticivorans in particular) and other potential environmental co-factors for the ongoing immune response in PBC. Of particular interest is 2-Octynoic acid, 60 which is present in commonly used cosmetic products and food flavourings and has the potential to modify PDC-E2 in an immunogenic direction. Elimination studies, like for gluten in coeliac disease, have not yet been performed to justify any particular advice on 2-Octynoic acid-related products for patients. 61 Unlike the case in PSC, antibiotic therapy in PBC has not been attempted outside the context of pruritus (rifampicin). Of the reported environmental 62, 63 risk factors in PBC, 64 smoking seems to be the only one to be accounted for in clinical counselling so far, given 65, 66 associations with an increased rate of liver fibrosis. Liver transplantation in PBC. In general, disease progression is more predictable in PBC than in PSC, and the utility of prognostic models (bilirubin, Mayo risk score and MELD, in particular) in the appropriate timing of liver transplantation is established Pruritus may, in a few cases, serve as the sole indication for liver transplantation. The improvement of fatigue following liver transplantation is less predictable and pronounced than other symptoms, 70, 71 and fatigue should, therefore, not trigger liver transplantation without the presence of other indications. There is little or no controversy as to incorporating symptomatic indications in the transplant assessments, even in areas with MELD-based graft allocation programmes. Hepatocellular carcinoma (HCC) may develop in PBC patients with advanced disease stages, 72, 73 and may also be associated with nonresponse to UDCA. 74 The patients should be followed accordingly Disease recurrence occurs in up to 30 35% of liver allografts in PBC recipients. 78 The variable frequencies between studies probably reflect differences in practice as to protocol biopsies and diagnostic criteria. There is no consensus as to treatment of UDCA in transplant recipients with recurrent PBC, but hepatic biochemistries improve upon administration like in the native liver disease Whether the choice of calcineurin inhibitor influences recurrence rates is debated. 81 Tacrolimus seems to associate with higher frequencies of recurrence and shorter recurrence-free survival than ciclosporine in many series. 81 Meta-analysis of available data as of January 2006, however, did not support a significant difference in PBC recurrence rates according to immunosuppressive regimen. On this basis, and as short- to mediate-term impact on overall and graft survival from PBC recurrence is neglible, 82 tacrolimus-based regimens remain standard at most centres. As very long-term (>10 20 years of follow-up) impact from PBC recurrence on re-transplantation rates is unknown, further considerations may become relevant as data accumulate. Management of PSC Diagnosis of PSC. There is emerging evidence that previous estimates of a frequency of PSC in IBD of 2 4% may be too low and that up to 10% of patients with IBD may show changes compatible with PSC on magnetic resonance cholangiography (MRC). 83, 84 The association between IBD and PSC remains one of the key features of PSC for which the basis is still not established. Hypotheses range from endotoxin leakage, 85 via pathogenic changes to the gut microbiota, 86 to aberrant homing of intestinally activated lymphocytes to engage in biliary 286 Aliment Pharmacol Ther 2014; 39:

6 Review: controversies in cholestatic diseases Table 1 Overview of clinical studies of non-ursodeoxycholic acid treatment in primary biliary cirrhosis (PBC). References for studies refer to the online supplementary reference list (Data S1 for tables 1 5) Study Year Treatment N (treat/ control) Study duration Lab Histology OLT-free survival Outcome Heathcote et al Azathioprine 45 (22/23) 5 years No effect on liver tests, histology or survival Christensen et al Azathioprine 248 (127/121) 11 years No effect on liver tests, histology or survival Minuk et al Ciclosporine vs. placebo 12 (6/6) 1 year + ND ND Improved liver tests, but high incidence of side Wiesner 1990 Ciclosporine vs. et al. 4 placebo Lombard 1993 Ciclosporine vs. et al. 5 placebo Lindor 1995 Methotrexate/ et al. 6 UDCA Gonzalez- Koch et al Methotrexate/ UDCA vs. UDCA Leuschner 1999 Budesonide/ et al. 8 UDCA vs. UDCA Nakai et al Bezafibrate/UDCA vs. UDCA Kurihara et al Bezafibrate vs. UDCA Itakura 2004 Bezafibrate/UDCA et al. 11 vs. UDCA Combes 2005 Methotrexate/ et al. 12 UDCA vs. UDCA Rautiainen 2005 Budesonide/ et al. 13 UDCA vs. UDCA Iwasaki et al Bezafibrate vs. UDCA Bezafibrate/UDCA vs. UDCA Mason 2008 Lamivudine/ et al. 15 zidovudine/udca vs. UDCA effects 29 (19/10) 2 years + + ND Improved liver tests (ALP, bilirubin) and AMA, improved histology compared with placebo years + Prolonged survival in Cox multivariate analysis was not confirmed in the univariate analysis Side effects (9% HT, 11% renal insufficiency) 32* 2 years ND Seven patients withdrawn because of side effects No effect on liver tests or histology 25 (13/12) 48 weeks ND No effect on liver tests or histology 39 (20/19) 2 years + + ND Improved liver tests, IgM, IgG, and histology 23 (10/13) 1 year + ND ND Combination therapy improved liver tests compared with UDCA 24 (12/12) 1 year + ND ND Improved liver tests more than UDCA 16 6 months + ND ND Improved liver tests years ( years) No effect on death, OLT, varices encephalopathy, bilirubin, histological progression by two stages or to cirrhosis 77 (41/36) 3 years + ND Budesonide improved histology, but did not result in additional improvement in liver tests 45 (20/25) 22 (12/10) 1 year 1 year Equal + ND ND ND ND Bezafibrate and UDCA monotherapy equally improved liver tests. Additional improvement with combination 59 6 months + ND ND Improved ALP, but did not improve primary end-points ALP, alkaline phosphatase; AMA, anti-mitochondrial antibodies; HT, hypertension; ND, not done; UDCA, ursodeoxycholic acid; OLT, orthotopic liver transplantation. The interested reader is guided to the following references for treatment reports not fulfilling the criteria for Table presentation, i.e. randomized allocation to either a treatment group or a control group receiving placebo, no treatment or UDCA * No controls included, but comparison with 180 patients in a UDCA vs. placebo study conducted during the same period. No controls, cross-over design with exchange of treatment protocols between the two groups after 6 months. Aliment Pharmacol Ther 2014; 39:

7 T. H. Karlsen et al. 87, 88 inflammatory processes. If the pathological processes involved can be dissected, it may be possible to develop diagnostic tools for early, potentially pre-clinical, detection of PSC in IBD patients. On the other hand, it is currently not known to what extent failure of medical therapy in PSC can be ascribed to an advanced disease stage with manifest strictures already at the time of diagnosis. As of yet, procedures to diagnose PSC are restricted to IBD patients in whom abnormal regular biochemical tests suggest the presence of liver disease. There is now consensus in both AASLD and EASL guidelines that MRC is the method of choice, unless endoscopic interventions or sampling is called for and endoscopic retrograde cholangiography (ERC) is indicated. Likely, the practice is sound, but IBD patients with normal biochemistries in whom an intensified colorectal screening programme could be justified if they proved to have PSC will be missed by this approach. 83 The topic of elevated levels of immunoglobulin G4 (IgG4) in 10 20% of patients with PSC has received much attention over the last years An unknown fraction of these patients is likely to have cholangitis in the context of autoimmune pancreatitis (AIP) as determined by the HISORt criteria 94 first reported in Asian 95, 96 populations. Modified criteria have been adopted for the application in patients with PSC, i.e. accounting also for patients with two or more main manifestations (elevated serum IgG4, suggestive pancreatic imaging findings, other organ involvement and bile duct or papilla Vateri biopsy with >10 IgG4 positive cells/hpf) in combination with a significant corticosteroid treatment response defined as markedly improved biliary strictures allowing stent removal, liver enzymes <2 9 ULN and significant decreases in serum IgG4 and CA19-9 levels. 97 Corticosteroid responsiveness is a central feature of these criteria. Serum IgG4 levels are also typically higher in patients with AIP than in PSC, although precise cut-off levels for serum IgG4 to distinguish the conditions are not firmly established. 98 It may be argued that IgG4 elevations in PSC arising outside the context of AIP is of uncertain importance and associates with pathogenetic processes in PSC per se. 99, 100 On the other hand, it has been suggested that disease behaviour in patients with PSC and even mild elevations of IgG4 shows atypical features, which include a more rapid disease progression. 90, 101 A pragmatic approach is to adopt IgG4 measurements as part of the routine diagnostic work-up of patients with suspected PSC (as already proposed by 67, 102 EASL and AASLD guidelines), and to keep the threshold at a reasonable level when selecting suspected cases for assessment of corticosteroid responsiveness. 97 Until refined criteria are available, sound clinical judgment, also accounting for corticosteroid side effects, is needed to guide decisions on the topic. Cancer surveillance in PSC. Historically, it is of interest to note the 10 years that passed from the first report on an increased risk of colorectal cancer in PSC 103 until the association was corroborated in meta-analysis of available and contrasting reports. 104 Colorectal cancer surveillance annually or biannually in PSC patients with IBD is now advised in both the EASL and AASLD guidelines. PSC presentation may precede that of IBD, and IBD may even present post-liver transplantation. 105 Furthermore, IBD in PSC typically runs a quiescent course, and may thus be missed. Regular re-evaluation by total colonoscopy and histology, for instance every 4 5 years, is therefore recommended by many authorities. We recently reviewed the present data on diagnosis of cholangiocarcinoma in PSC. 109 The main problem is that of early diagnosis, and so far, there are no consensus guidelines as to robust screening protocols. A recent population-based patient series from the Netherlands questions previous notions that late presentation of cholangiocarcinoma is a rare event, 110 with 37% of cholangiocarcinomas presenting more than 10 years after diagnosis of PSC. 111 Clinical and biochemical deterioration at any point in the disease course should therefore always result in reflections as to a potentially malignant explanation. There is some evidence that imaging routinely should be incorporated in PSC patient follow-up, 112 and MRC or ultrasound is included in patient follow-up at many centres. The EASL guidelines advise for annual ultrasound to detect gall-bladder mass lesions, 67, 113 but neither this practice nor the utility of other imaging modalities in early cholangiocarcinoma detection has so far been validated. The ability of FUT2/ FUT3 genotyping to improve CA19-9 test performance also needs prospective evaluation and validation. 114 With few exceptions, investigations of brush cytology specimens, obtained at ERC by brushing in a region of a suspicious stricture, have a specificity of % for cholangiocarcinoma in PSC in published series (Table 2). The problem with the method is highlighted by the variable sensitivity. Operator variability as well as differences in the criteria defining a positive test is likely to contribute to the variable sensitivity. 115 Technical aspects of brushing at ERC and intrinsic variability in cholangiocarcinomas may also play a role. Repeated brushings can improve the sensitivity of this method, 116 a practice also 288 Aliment Pharmacol Ther 2014; 39:

8 Review: controversies in cholestatic diseases employed at our centre on inconclusive findings in a suspicious clinical context. As shown in Table 2, various means of structural chromatin/dna assessments, by fluorescent probe hybridisation, digitised image analysis or flow cytometry, generally improve sensitivity and are incorporated in clinical routine diagnostics of brush cytology specimens at many referral centres. As reviewed elsewhere, 109 molecular biomarkers for cholangiocarcinoma in PSC are awaited and expected to improve sensitivity even further. However, the path forward to clinical validation of these makers is likely to still take some years, due to scarcity of patients and only recent establishing of systematic prospective patient biobanking in the international PSC research network ( org). Current medical treatment of PSC. The AASLD guidelines advise against the use of UDCA as medical therapy in PSC, concluding at a class I, level A recommendation (see above for criteria definitions). 102 The EASL guidelines have a more compound conclusion, suggesting that UDCA improves serum liver tests and surrogate markers of prognosis, but does not reveal a proven benefit on survival. Thus, they conclude that present data do not yet allow a specific recommendation for the general use of UDCA in PSC. 67 The controversy surrounding UDCA use has several reasons. These partly derive from the lack of effect on clinical end-points in partly underpowered clinical trials (Table 3) and partly from a study using a high dose of UDCA (28 30 mg/kg/day), which culminated in an increase in clinical end-points including colorectal dysplasia. 117, 118 There is an increasing enrichment of biliary UDCA in patients with PSC, from 43 47% at normal doses (10 17 mg/kg/day) to 56 59% at higher doses (18 32 mg/kg/day), 119 along with increased delivery of unabsorbed UDCA to the colon for bacterial metabolisation. The mechanisms explaining the detrimental effects of high-dose UDCA have not been fully elucidated and conflicting pilot data on high-dose UDCA in PSC do exist. 120, 121 In effect, many centres still offer UDCA to patients on the basis of clinical experience and tradition and argue that only the high-- dose UDCA regimen should be abandoned. 122 To what extent UDCA-responsive subsets of PSC patients can be defined (e.g. on the basis of ALP changes like in PBC , 125 ) is not yet clear. Future medical treatment of PSC. Like in PBC, there is no other bile acid than UDCA in clinical use for the treatment of PSC. Based on promising phase I and animal data, nor-udca is currently in phase II clinical trials ( ). A variety of immunosuppressives, antibiotics and other compounds have been tested over the years, often in the context of poor study design and in trials of limited duration. However, some trials are of comparable size and quality as the trials evaluating the use of UDCA in PSC (Table 4). More recently, there has been a 86, 129 renewed interest in antibiotic treatment, largely deriving from rapidly emerging data regarding the interrelationship among bile acid metabolism, systemic and mucosal inflammation and the gut microbiota However, specific roles for the gut microbiota in PSC pathogenesis, albeit an intriguing possibility, are still devoid of robust experimental support. Furthermore, knowledge may emerge on specific mechanisms for which broad antibacterial interventions like antibiotics may not represent the appropriate treatment approach. Therapies targeting fibrogenesis are also of interest in PSC, e.g. lysyl oxidase-like ( ct2/show/nct ). There is little controversy as to the application of widely variable treatment approaches in PSC, given uncertainties that still exist regarding pathogenesis. 135 Clinical trials are hampered by inherent limitations such as a slowly progressing disease and lack of applicable prognostic indices (Table 5). This includes a lack of or consensus protocols for assessing disease progression by available imaging modalities (MRC, transient elastography) The outcomes of ongoing clinical trials are therefore likely to have flaws intrinsic to study design and disease behaviour as much as choice of treatment targets. Endoscopic treatment in PSC. There are also differences in the practice preferences related to the main treatment options for PSC, comprising endoscopic interventions and liver transplantation. For endoscopy, an ongoing trial aims to clarify whether balloon dilatation or short-term (2 3 weeks) stenting is the preferable management for bile duct strictures ( clinicaltrials.gov/ct2/show/nct ). Both strategies are in current practice, yet the additional 141, 142 value of stenting is not established and has been claimed to associate with increased frequencies of cholangitis. 143 As to either approach, the threshold for intervention is often left at the discretion of the endoscopist, a decision likely to be biased by spontaneous fluctuations in bile flow and cholestatic parameters in PSC. 144 Aliment Pharmacol Ther 2014; 39:

9 T. H. Karlsen et al. Table 2 Results of studies on the diagnostic utility of biliary brush cytology with and without DNA analysis [by fluorescence in situ hybridisation (FISH), digital image analysis (DIA) or flow cytometry] in primary sclerosing cholangitis. Differences in classification algorithms, brush cytology specimen collection procedures, as well as operator variability make direct comparisons difficult and are likely to underlie parts of the differences. Implementation of DNA analysis in the diagnostic protocols has a growing amount of scientific basis, but there is controversy as to the management of detected abnormities. References for studies refer to the online supplementary reference list (Data S1 for tables 1 5) PSC Brush Sensitivity Specificity Author Time period Country patients (n) samples (n) classification Method (%) (%) Comment Ponsioen et al Amsterdam, The Netherlands Siqueira et al Pittsburgh, PA, US Lindberg et al Stockholm, Sweden Lal et al Chicago, Illinois, US Moff et al Baltimore, MD, US Furmanczyk Seattle, WA, US 51 (37 with et al. 40 follow-up) Moreno Luna Mayo Clinic, et al. 41 MN, US No abnormalities Reactive changes Some atypia Suspicious Adenocarcinoma Negative Suspicious Highly atypical Positive 20 Insufficient Benign Abnormal, but probably benign Suspicious, but inconclusive Probably malignant Malignant Benign Atypical Malignant Unsatisfactory Benign/reactive Atypical Malignant 107 Negative Atypical Suspicious Positive 86 Benign Atypical Suspicious Malignant Boberg et al Oslo, Norway Insufficient Normal Indefinite for dysplasia Low-grade dysplasia High-grade dysplasia adenocarcinoma Suspicious or adenoca Positive Flow cytometric DNA analysis n.d. 94 n.d. n.d. Positive Positive or suspicious Positive Positive or suspicious DIA Aneuploid or tetraploid FISH Polysomy or trisomy or3 Polysomy neither positive nor suspicious: DIA Aneuploid or tetraploid FISH Polysomy or trisomy or3 Polysomy DIA + FISH Aneuploidy/tetraploid polysomy/trisomy High-grade dysplasia Low-grade + high-grade dysplasia 290 Aliment Pharmacol Ther 2014; 39:

10 Review: controversies in cholestatic diseases Table 2 (Continued) PSC Brush Sensitivity Specificity Author Time period Country patients (n) samples (n) classification Method (%) (%) Comment Levy et al. 43 Mayo Clinic, 34 Inadequate MN, US Negative Positive Atypical Positive or suspicious Suspicious DIA Positive FISH Trisomy 7 benign Trisomy 7 malignant DIA + FISH Trisomy 7 benign Trisomy 7 malignant neither positive nor suspicious: DIA FISH Trisomy 7 benign Trisomy 7 malignant DIA + FISH Trisomy 7 benign Trisomy 7 malignant Charatcharoenwitthaya Mayo Clinic, et al. 44 MN, US Benign Atypical Positive Suspicious Positive or suspicious Malignant DIA Aneuploid or tetraploid FISH Polysomy or trisomy Polysomy DIA + FISH Aneuploidy/tetraploid polysomy/trisomy Bangarulingam et al Mayo Clinic, 235 Negative FISH Patients with FISH polysomy had MN, US Atypical Polysomy outcome similar to patients with Suspicious Trisomy/tetrasomy CCA Positive Patients with FISH trisomy/ tetrasomy had outcome similar to patients with negative FISH Conclusion: FISH should be interpreted with caution Halme et al Helsinki, Benign 5 aneuploid cases with benign Finland Suspicious Suspicious cytology had dysplasia or cancer Malignant DNA content on histology DNA + cytology for patients with end-point DNA + cytology for whole cohort Barr Fritcher et al Mayo Clinic, 30 Selected patients Patients with serial FISH polysomy MN, US (n = 30) with FISH are more likely to have CCA on polysomy, but no follow-up than those with definite CCA for subsequent non-polysomy FISH follow-up Barr Fritcher et al Mayo Clinic, 102 Selected only Univariate Cox model: MN, US equivocal cytology: Suspicious cytology: Atypical HR 1.90 ( ) Suspicious (P = 0.066) FISH polysomy: HR 8.70 ( )(P < 0.001) Multivariate Cox model: FISH polysomy: HR 6.96 ( )(P < 0.001) CCA, cholangiocarcinoma; HR, hazard ratio; ND, not done. Liver transplantation in PSC. Pruritus, more rarely, is the sole indication for liver transplantation in PSC compared with PBC due to correlation of pruritus with biliary stricture severity to a larger degree in PSC than in PBC. The appropriate timing of liver transplantation for PSC vs. the risk of biliary dysplasia and cancer is more complex. 145 The EASL guidelines consider cholangiocyte dysplasia as well as severe recur- Aliment Pharmacol Ther 2014; 39:

11 T. H. Karlsen et al. Table 3 Overview of clinical studies of treatment with ursodeoxycholic acid in primary sclerosing cholangitis (PSC). References for studies refer to the online supplementary reference list (Data S1 for tables 1 5) Study Year Dose (mg/kg bw/ day) N (treat/ control) Study duration Lab Histology CCA OLT-free survival Outcome O Brien et al * 2.5 years + ND ND ND Improvement of liver tests in treatment periods and worsening in nontreatment periods Beuers et al (6/8) 1 year + + ND ND Significant improvement in liver biochemistry Stiehl et al /day 20 (10/10) 3 months + ND ND ND Significant improvement in liver tests De Maria et al. 52 * b.d. 40 (20/20) 2 years No effect on liver tests or cholangiography Lindor et al (51/51) 2.2 years + ND No significant effect on primary end-points (death, OLT, histology, lab) Mitchell et al (13/13) 2 years + + ND ND UDCA group had improved liver test results, histology and cholangiography Harnois et al year + ND ND Improved Mayo Risk Score for UDCA vs. placebo and for highdose vs. low-dose UDCA Improved liver test results Olsson et al (97/101) 5 years (+) ND No effect on death, OLT, CCA or liver tests Lindor et al (76/73) 6 years + ND Terminated at 6 years as worse outcome in treatment group for death or OLT Improved liver tests in UDCA group UDCA, ursodeoxycholic acid; ND, not determined; CCA, cholangiocarcinoma; OLT, orthotopic liver transplantation. The interested reader is guided to the following references for treatment reports not fulfilling the criteria for Table presentation, i.e. randomised allocation to either a treatment group receiving UDCA or a control group receiving placebo or no treatment * Cross-over design: 3 months pre-treatment, 6 months treatment, 3 months withdrawal, 18 months re-treatment. Uniform dose not adjusted to body weight. Controls were 52 placebo/52 low-dose UDCA using data from Lindor et al. 57 rent bacterial cholangitis as potential indications for liver transplantation. The AASLD guidelines have a notion of liver transplantation with neoadjuvant chemotherapy and brachytherapy ( the Mayo protocol ), 102 but do not specifically consider biliary dysplasia. In the Nordic countries, which do not have MELD-based organ allocation, biliary dysplasia detected by brush cytology may serve as the sole indication for liver transplantation. The practice has been criticised on the basis that 1/3 of PSC patients may exhibit cholangiocellular dysplasia in the absence of cholangiocarcinoma, and further validation is needed Clearly, upon improvements in biomarkers for early cholangiocarcinoma detection, an evidence-based shift toward earlier transplantation in these patients will be feasible. As of yet, decision-making is largely based on the experience and preference of each individual transplant programme. 292 Aliment Pharmacol Ther 2014; 39:

12 Review: controversies in cholestatic diseases Table 4 Overview of clinical studies of non-ursodeoxycholic acid treatment in primary sclerosing cholangitis. References for studies refer to the online supplementary reference list (Data S1 for tables 1 5) Study Year Treatment N (treat/ placebo) Study duration Lab Histology OLT-free survival Outcome La Russo et al Penicillamine 70 (39/31) 3 years No effect on liver tests, histology or survival Knox et al Methotrexate 24 (12/12) 2 years + (ALP only) Improved ALP. No effect on histology, cholangiography or outcome Olsson et al Colchicine 84 (44/40) 3 years No effect on liver tests, histology or survival Sterling et al Mycophenolate mofetil/udca vs. UDCA 25 (12/13) 2 years No effect on liver tests, histology, cholangiography or Mayo Risk Score Farkkila 2004 Metronidazole/ et al. 79 UDCA 80 (39/41) 36 months + (+) Improved liver tests and Mayo Risk Score, but no improvement in histology or cholangiography Hommes et al Infliximab 10 (6/4) 12 months ND Patient enrolment was prematurely stopped when interim analysis showed no treatment benefit. No effect on liver tests, histology ALP, alkaline phosphatase; UDCA, ursodeoxycholic acid; ND, not done; OLT, orthotopic liver transplantation. The interested reader is guided to the following references for treatment reports not fulfilling the criteria for table presentation, i.e. randomised allocation to either a treatment group or a control group receiving placebo or no treatment with the aim of evaluating effect on pre-transplant PSC Table 5 Predictive models for primary sclerosing cholangitis (PSC) progression. References for studies refer to the online supplementary reference list (Data S1 for tables 1 5) Study Year Variables in predictive model Pugh et al Bilirubin, albumin, INR, encephalopathy, ascites (Child-Pugh score) Wiesner et al Age, bilirubin, histological stage, haemoglobin, IBD (Mayo risk score) Farrant et al Age, histological stage, hepatomegaly, splenomegaly, alkaline phosphatase (King s College Hospital) Dickson et al Age, bilirubin, histological stage, splenomegaly Broome et al Age, bilirubin, histological stage Kim et al Age, bilirubin, albumin, AST, variceal bleeding (revised Mayo risk score) Kamath et al Bilirubin, creatinine, INR (MELD score) Boberg et al Age at diagnosis, bilirubin, albumin Ponsioen et al Age, cholangiographic score Tischendorf et al Age, albumin, bilirubin elevation >3 months, hepatomegaly, splenomegaly, dominant bile duct stenosis, intra- and extrahepatic bile duct changes ( PSC score ) AST, aspartate aminotransferase; IBD, inflammatory bowel disease; INR, international normalised ratio; MELD, model of end-stage liver disease. Immunosuppressive regimens in liver-transplanted 149, 150 PSC patients are now mainly tacrolimus-based. There is no firm evidence that the choice of immunosuppressive regimen directly affects risk of PSC recurrence. However, there is an, as of yet not fully 81, 149 understood, interrelationship between post-transplant IBD activity (requiring intensified corticosteroid treatment) and increased PSC recurrence rates. A 149, 151 cause effect relationship between IBD activity and PSC occurrence (or, more appropriately, re-occurrence) is adopted by most authors as the most likely explanation, but alternative mechanisms (e.g. intrinsically high disease Aliment Pharmacol Ther 2014; 39:

13 T. H. Karlsen et al. activity of both bile duct and colonic inflammation) may also prove correct. There is also a relationship between acute cellular rejection (against which corticosteroids would protect) and PSC recurrence. 152 The topic is of considerable interest as long-term follow-up indicates that PSC recurrence does increase re-transplantation rates. 153 Interpreting the relationship between disease recurrence and immunosuppression is further complicated by associations between tacrolimus-based regimens and IBD flares following liver transplantation in PSC As of yet, evidence does not allow for firm recommendations either on timing of colectomy (pre-transplant in patients with high-activity IBD pre-transplant?) or choice of immunosuppression (ciclosporine-based regimens in patients with high-activity IBD post-transplant?). Likely, on a more comprehensive appreciation of disease mechanisms in PSC and IBD in PSC, immunosuppression regimens post-liver transplantation in PSC that accounts not only for allograft rejection issues but also for PSC immunopathology can be designed. Common features in PBC and PSC Autoimmune hepatitis. A consensus document from the International Autoimmune Hepatitis Group (IAIHG) deals thoroughly with the controversy as to whether overlap syndrome (Figure 2) should be considered a separate disease entity. 157 If the patients fulfil a diagnosis of PBC or PSC, this should, according to this consensus document, be the primary diagnosis and co-occurring features of autoimmune hepatitis should be determined using general considerations (ALT at least 59 ULN, IgG at least 29 ULN, histological features of autoimmune hepatitis) rather than the IAIHG scoring systems. 158 Identification of patients for corticosteroid therapy is not straightforward. Treatment response to corticosteroids in PSC and PBC patients with concomitant features of autoimmune hepatitis is generally less pronounced than in patients with autoimmune hepatitis as the primary diagnosis, 159, 160 and more so in PSC than in PBC. 161, 162 It is thus important to be aware of the risk of side effects (osteoporosis in particular) and to assess treatment response regularly, as well as to consider steroid sparing agents for patients requiring long-term treatments. 67 Cholestatic liver cirrhosis. To what extent defects of bile acid homoeostasis involve in the primary insult in PBC and PSC is still debated. 163 Regardless of the aetiological basis of bile duct injury in PBC and PSC, development of liver fibrosis throughout the disease course most likely involves bile acid toxicity at some level. 1 The hepatocyte initiates adaptive responses during cholestasis (Figure 3), including the (i) downregulation of bile acid synthesis and hepatocellular bile acid uptake, (ii) increased hydroxylation and conjugation to make bile acids more water soluble and (iii) induction of bile acid efflux pumps on the sinusoidal membrane leading to export of metabolised bile acids to the systemic circulation for renal elimination. Together with FXR and PXR, the constitutive androstane receptor (CAR) is a major determinant of the expression of the genes involved in this adaption. 164, 165 The concept of directing or augmenting these adaptive mechanisms during cholestasis forms the basis of several ongoing treatment trials (e.g. obeticholic acid), but so far remains to be proven. At the level of the cholangiocyte, several lines of evidence converge on the importance of apical bicarbonate secretion (the bicarbonate umbrella hypothesis) in preventing the protonation of luminal bile acids and thus reducing cellular injury. 163, 166 The bile acid receptor TGR5 is involved in these mechanisms, but so far therapeutic efficacy for TGR5 agonism in cholestatic liver disease seems to occur in conjunction with FXR effects. 167 Importantly, the risk of accelerating cholangiocarcinoma development argues against human applications of TGR5 agonists in PSC. 167 The role of the gut microbiota in modifying the cholestatic bile acid pool within the enterohepatic circulation and vice versa also needs to be defined (Figure 3) Pruritus. The large number of candidate pruritogens in cholestatic liver disease launched over the years is reviewed elsewhere More recently, two groups have reported on slightly differing aspects of cholestatic pruritus. 171, 172 An Amsterdam group identified lysophosphatidic acid (LPA) as a pruritogen produced by autotaxin 171 and associating with itching behaviour in mice. In humans, the serum activity of autotaxin correlated with itch intensity and was reduced upon treatment with nasobiliary drainage. Similar correlations were not observed for bile salts, in contrast to findings recently reported from a San Francisco group, which detected correlations with itching behaviour and TGR5 activation status. 172 Intradermal injection of bile acids and a TGR5-agonist induced itch behaviour in the experimental setup, which also included detection of reduced itch behaviour in tgr5-/- mice and spontaneous itching behaviour in TGR5 overexpressing mice. The main criticism against the TGR5 data pertains to the doses of deoxycholic acid used in the experi- 294 Aliment Pharmacol Ther 2014; 39:

14 Review: controversies in cholestatic diseases Liver - detoxification De novo synthesis Cyp7A Sinusoidal uptake Canalicular export BSEP MRP2 MDR3 Hydroxylation Cyp3A Conjugation UGT SULT MRP3 MRP4 Sinusoidal export GST OST NTCP OATP Enterohepatic circulation Bile duct - bicarbonate protection CFTR AE2 TGR5 Figure 3 Traditions of bile acid research and the concept of bile acid toxicity serve as the main basis for present therapies in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC), as well as for most of the ongoing treatment trials. At the level of the liver, protective mechanisms in a context of cholestatic liver disease involve regulation of bile acid transport and metabolism (red, downregulation generally beneficial; blue, upregulation generally beneficial). At the level of the bile ducts, protective mechanisms involve apical bicarbonate secretion by the cholangiocytes (blue). There is emerging evidence that the gut microbiota, during the intestinal phase of the enterohepatic circulation, influences these mechanisms and serves additional regulatory mechanisms. There is an ongoing controversy in PBC and PSC as to the importance of these mechanisms as compared with primarily immunemediated liver and bile duct injury. Cyp (cytochrome P450), UGT (uridine diphosphate glucuronosyltransferase), SULT (sulfotransferase), GST (glutathione S-transferase), BSEP (bile salt export pump), MRP2, 3 and 4 (multidrug resistance-associated protein 2, 3 and 4), MDR3 (multidrug resistance protein 3), OST (organic solute transporter, OSTa-OSTb heterodimer), ASBT (apical sodium-dependent bile acid transporter), IBABP (ileal bile acid-binding protein), NTCP (Na+-taurocholate cotransporting polypeptide), OATP (several organic anion transporting polypeptides), CFTR (cystic fibrosis transmembrane conductance regulator), AE2 (anionic exchanger 2), TGR5 (Takeda G-protein coupled receptor 5). ments, 170 which range far above physiological concentrations in cholestasis. 173 Furthermore, the concentrations used to elicit itching in vivo may also induce mast cell degranulation and thus cause itching via non-tgr5 mechanisms. 174 Further studies are likely to elaborate on both TGR5 and autotaxin-associated aspects of pruritus and thus potentially open up for novel treatment options. Fatigue. The pathogenetic basis for fatigue in cholestatic liver disease, sometimes pronounced and debilitating, is not known. The most pronounced affections occur in PBC, where more than half of the patients have been reported to suffer from fatigue. 175, 176 Many of these patients report fatigue to represent the predominant cause of reduced quality of life The range of causes proposed to cause fatigue in PBC is large and Aliment Pharmacol Ther 2014; 39: