Hirschfield, Gideon M.

AbstractBackground & AimsMachine learning (ML) provides new approaches for prognostication through the identification of novel subgroups of patients. We explored whether ML could support disease sub‐phenotyping and risk stratification in primary biliary cholangitis (PBC).MethodsML was applied to an international dataset of PBC patients. The dataset was split into a derivation cohort (training set) and a validation cohort (validation set), and key clinical features were analysed. The outcome was a composite of liver‐related death or liver transplantation. ML and standard survival analysis were performed.ResultsThe training set was composed of 11,819 subjects, while the validation set was composed of 1,069 subjects. ML identified four clusters of patients characterized by different phenotypes and long‐term prognosis. Cluster 1 (n = 3566) included patients with excellent prognosis, whereas Cluster 2 (n = 3966) consisted of individuals at worse prognosis differing from Cluster 1 only for albumin levels around the limit of normal. Cluster 3 (n = 2379) included young patients with florid cholestasis and Cluster 4 (n = 1908) comprised advanced cases. Further sub‐analyses on the dynamics of albumin within the normal range revealed that ursodeoxycholic acid‐induced increase of albumin >1.2 x lower limit of normal (LLN) is associated with improved transplant‐free survival.ConclusionsUnsupervised ML identified four novel groups of PBC patients with different phenotypes and prognosis and highlighted subtle variations of albumin within the normal range. Therapy‐induced increase of albumin >1.2 x LLN should be considered a treatment goal.

Autoimmune liver disease (AILD) spans a spectrum of chronic disorders affecting the liver parenchyma and biliary system. Three main categories of AILD are autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC). This review condenses the presentation and discussions of the Single Topic Conference (STC) on AILD that was held in Ottawa, Ontario, in November 2019. We cover generalities regarding disease presentation and clinical diagnosis; mechanistic themes; treatment paradigms; clinical trials, including approaches and challenges to new therapies; and looking beyond traditional disease boundaries. Although these diseases are considered autoimmune, the etiology and role of environmental triggers are poorly understood. AILDs are progressive and chronic conditions that affect survival and quality of life. Advances have been made in PBC treatment because second-line treatments are now available (obeticholic acid, bezafibrate); however, a significant proportion still present suboptimal response. AIH treatment has remained unchanged for several decades, and data suggest that fewer than 50% of patients achieve a complete response and as many as 80% develop treatment-related side effects. B-cell depletion therapy to treat AIH is in an early stage of development and has shown promising results. An effective treatment for PSC is urgently needed. Liver transplant remains the best option for patients who develop decompensated cirrhosis or hepatocellular carcinoma within specific criteria, but recurrent AILD might occur. Continued efforts are warranted to develop networks for AILD aimed at assessing geo-epidemiological, clinical, and biochemical differences to capture the new treatment era in Canada.

Background and Aims Lifetime risk of biliary tract cancer (BTC) in primary sclerosing cholangitis (PSC) may exceed 20%, and BTC is currently the leading cause of death in patients with PSC. To open new avenues for management, we aimed to delineate clinically relevant genomic and pathological features of a large panel of PSC‐associated BTC (PSC‐BTC). Approach and Results We analyzed formalin‐fixed, paraffin‐embedded tumor tissue from 186 patients with PSC‐BTC from 11 centers in eight countries with all anatomical locations included. We performed tumor DNA sequencing at 42 clinically relevant genetic loci to detect mutations, translocations, and copy number variations, along with histomorphological and immunohistochemical characterization. Regardless of the anatomical localization, PSC‐BTC exhibited a uniform molecular and histological characteristic similar to extrahepatic cholangiocarcinoma. We detected a high frequency of genomic alterations typical of extrahepatic cholangiocarcinoma, such as TP53 (35.5%), KRAS (28.0%), CDKN2A (14.5%), and SMAD4 (11.3%), as well as potentially druggable mutations (e.g., HER2/ERBB2). We found a high frequency of nontypical/nonductal histomorphological subtypes (55.2%) and of the usually rare BTC precursor lesion, intraductal papillary neoplasia (18.3%). Conclusions Genomic alterations in PSC‐BTC include a significant number of putative actionable therapeutic targets. Notably, PSC‐BTC shows a distinct extrahepatic morpho‐molecular phenotype, independent of the anatomical location of the tumor. These findings advance our understanding of PSC‐associated cholangiocarcinogenesis and provide strong incentives for clinical trials to test genome‐based personalized treatment strategies in PSC‐BTC.

Objective The clinical benefit of ursodeoxycholic acid (UDCA) in primary biliary cholangitis (PBC) has never been reported in absolute measures. The aim of this study was to assess the number needed to treat (NNT) with UDCA to prevent liver transplantation (LT) or death among patients with PBC. Methods The NNT was calculated based on the untreated LT-free survival and HR of UDCA with respect to LT or death as derived from inverse probability of treatment weighting-adjusted Cox proportional hazard analyses within the Global PBC Study Group database. Results We included 3902 patients with a median follow-up of 7.8 (4.1–12.1) years. The overall HR of UDCA was 0.46 (95% CI 0.40 to 0.52) and the 5-year LT-free survival without UDCA was 81% (95% CI 79 to 82). The NNT to prevent one LT or death within 5 years (NNT5y) was 11 (95% CI 9 to 13). Although the HR of UDCA was similar for patients with and without cirrhosis (0.33 vs 0.31), the NNT5y was 4 (95% CI 3 to 5) and 20 (95% CI 14 to 34), respectively. Among patients with low alkaline phosphatase (ALP) (≤2× the upper limit of normal (ULN)), intermediate ALP (2–4× ULN) and high ALP (>4× ULN), the NNT5y to prevent one LT or death was 26 (95% CI 15 to 70), 11 (95% CI 8 to 17) and 5 (95% CI 4 to 8), respectively. Conclusion The absolute clinical efficacy of UDCA with respect to LT or death varied with baseline prognostic characteristics, but was high throughout. These findings strongly emphasise the incentive to promptly initiate UDCA treatment in all patients with PBC and may improve patient compliance.

Changes over time in the presenting features and clinical course of patients with primary biliary cholangitis are poorly described. We sought to describe temporal trends in patient and disease characteristics over a 44‐year period across a large international primary biliary cholangitis cohort of 4,805 patients diagnosed between 1970 and 2014, from 17 centers across Europe and North America. Patients were divided into five cohorts according to their year of diagnosis: 1970‐1979 (n = 143), 1980‐1989 (n = 858), 1990‐1999 (n = 1,754), 2000‐2009 (n = 1,815), and ≥2010 (n = 235). Age at diagnosis, disease stage, response to ursodeoxycholic acid, and clinical outcomes were compared. Mean age at diagnosis increased incrementally by 2‐3 years per decade from 46.9 ± 10.1 years in the 1970s to 57.0 ± 12.1 years from 2010 onward (P < 0.001). The female to male ratio (9:1) and antimitochondrial antibody positivity (90%) were not significantly variable. The proportion of patients presenting with mild biochemical disease (according to Rotterdam staging) increased from 41.3% in the 1970s to 72.2% in the 1990s (P < 0.001) and remained relatively stable thereafter. Patients with a mild histological stage at diagnosis increased from 60.4% (1970‐1989) to 76.5% (1990‐2014) (P < 0.001). Correspondingly, response to ursodeoxycholic acid according to Paris‐I criteria increased; 51.7% in the 1970s and 70.5% in the 1990s (P < 0.001). Recent decades were also characterized by lower decompensation rates (18.5% in the 1970s to 5.8% in the 2000s, P < 0.001) and higher 10‐year transplant‐free survival (48.4%, 68.7%, 79.7%, and 80.1% for each respective cohort; P < 0.001). Conclusion: In recent decades, a pattern of primary biliary cholangitis presentation consistent with an older age at diagnosis alongside reduced disease severity has been noted; the observed trends may be explained by an increase in routine testing of liver function and/or a changing environmental trigger. (Hepatology 2018;67:1920‐1930).

Objective Primary sclerosing cholangitis (PSC) is a genetically complex, inflammatory bile duct disease of largely unknown aetiology often leading to liver transplantation or death. Little is known about the genetic contribution to the severity and progression of PSC. The aim of this study is to identify genetic variants associated with PSC disease progression and development of complications. Design We collected standardised PSC subphenotypes in a large cohort of 3402 patients with PSC. After quality control, we combined 130 422 single nucleotide polymorphisms of all patients—obtained using the Illumina immunochip—with their disease subphenotypes. Using logistic regression and Cox proportional hazards models, we identified genetic variants associated with binary and time-to-event PSC subphenotypes. Results We identified genetic variant rs853974 to be associated with liver transplant-free survival (p=6.07×10–9). Kaplan-Meier survival analysis showed a 50.9% (95% CI 41.5% to 59.5%) transplant-free survival for homozygous AA allele carriers of rs853974 compared with 72.8% (95% CI 69.6% to 75.7%) for GG carriers at 10 years after PSC diagnosis. For the candidate gene in the region, RSPO3, we demonstrated expression in key liver-resident effector cells, such as human and murine cholangiocytes and human hepatic stellate cells. Conclusion We present a large international PSC cohort, and report genetic loci associated with PSC disease progression. For liver transplant-free survival, we identified a genome-wide significant signal and demonstrated expression of the candidate gene RSPO3 in key liver-resident effector cells. This warrants further assessments of the role of this potential key PSC modifier gene.

Primary sclerosing cholangitis (PSC) is strongly associated with several human leukocyte antigen (HLA) haplotypes. Due to extensive linkage disequilibrium and multiple polymorphic candidate genes in the HLA complex, identifying the alleles responsible for these associations has proven difficult. We aimed to evaluate whether studying populations of admixed or non‐European descent could help in defining the causative HLA alleles. When assessing haplotypes carrying HLA‐DRB1*13:01 (hypothesized to specifically increase the susceptibility to chronic cholangitis), we observed that every haplotype in the Scandinavian PSC population carried HLA‐DQB1*06:03. In contrast, only 65% of HLA‐DRB1*13:01 haplotypes in an admixed/non‐European PSC population carried this allele, suggesting that further assessments of the PSC‐associated haplotype HLA‐DRB1*13:01‐DQA1*01:03‐DQB1*06:03 in admixed or multi‐ethnic populations could aid in identifying the causative allele.

Primary sclerosing cholangitis (PSC) is a rare, but serious, cholestatic disease for which, to date, no effective therapy exists to halt disease progression toward end‐stage liver disease. Clinical trial design to study drugs that improve prognosis is hampered by the relatively low event rate of clinically relevant endpoints. To overcome this shortcoming, there is an urgent need to identify appropriate surrogate endpoints. At present, there are no established surrogate endpoints. This article provides a critical review and describes the results of a consensus process initiated by the International PSC Study Group to delineate appropriate candidate surrogate endpoints at present for clinical trials in this frequently dismal disease. The consensus process resulted in a shortlist of five candidates as surrogate endpoints for measuring disease progression: alkaline phosphatase (ALP); transient elastography (TE); histology; combination of ALP+histology; and bilirubin. Of these, histology, ALP, and TE came out as the most promising. However, the expert panel concluded that no biomarker currently exceeds level 3 validation. Combining multiple endpoints is advisable. Conclusion: At present, there are insufficient data to support level 2 validation for any surrogate endpoint in PSC. Concerted efforts by all stakeholders are highly needed. Novel, promising noninvasive biomarkers are under study and should be incorporated as exploratory endpoints in clinical trials. (Hepatology 2016;63:1357–1367)

SummaryBackgroundThe relationships between primary sclerosing cholangitis (PSC) and the environment are largely unknown.AimTo validate associations reported in previous studies and to identify novel environmental exposures among PSC patients.MethodsWe performed a multicenter, case–control analysis utilising self‐administered questionnaires. Responses between cases (n = 1000) and controls (n = 663) were compared using multivariable logistic regression adjusted for age and gender. The model was further stratified based on inflammatory bowel disease (IBD) status (with IBD n = 741 without IBD n = 259).ResultsSmoking was associated with PSC only when IBD was present (OR, 0.5; 95% CI 0.4–0.7) but not among those PSC patients without IBD (OR, 0.9; 95% CI 0.7–1.2). Compared to controls, women with PSC (irrespective of the presence of IBD) were less likely to have received hormone replacement therapy (HRT; OR, 0.5; 95% CI 0.4–0.7) and were more likely to have recurrent urinary tract infections (OR, 1.6; 95% CI 1.2–2.3). PSC patients regardless of gender or IBD status were less likely to eat fish (OR, 0.4; 95% CI 0.3–0.6) and grilled/barbecued meat (OR, 0.8; 95% CI 0.7–0.9). In contrast, PSC patients with and without IBD were more likely to consume steak/burgers that were more well done (OR, 1.3; 95% CI 1.2–1.5).ConclusionsIBD (rather than PSC) is associated with smoking. Women with PSC are more likely to have recurrent urinary tract infections and less likely to receive HRT. Dietary intake and methods of food preparation differ in PSC patients when compared to controls.