Exploring the Effects of Bile Acid Inhibition in Cholestatic Pruritus

Ph. D. Thesis.Pruritus (itch) is an important symptom associated with cholestatic liver diseases. The aim of this work was to study cholestatic pruritus to further our understanding of the prevalence in primary biliary cholangitis (PBC) and explore the role of inhibiting circulating bile acids (BAs) in relieving cholestatic pruritus. The cross-sectional study of pruritus from over 2800 patients from the UK-PBC research cohort showed that prevalence of pruritus in PBC is high (74%) with a significant proportion of patients reporting severe itch during the course of their disease. This study also highlighted the undertreatment of itch with inadequate use of guideline recommended drugs in the UK. The impact of inhibiting circulating BAs on cholestatic pruritus was studied in two different ways- i) via nasobiliary drainage (NBD, i.e. external diversion of bile and BAs away from the ileum), and ii) via pharmacological inhibition of the ileal bile acid transporter (IBAT) that mediates enterohepatic circulation of BAs. The retrospective cohort study of NBD showed the intervention is a highly effective treatment, but only of short-term durability and associated with high complication rate. The phase 2 clinical trial of GSK2330672, a human IBAT inhibitor agent, showed that two-weeks of treatment significantly reduced pruritus severity compared to placebo. The metabonomic and microbiome studies explored the serum metabonome and gut microbiota profile of pruritus in PBC. In addition, the effects of GSK2330672 on metabonome and gut microbiome were investigated. The study demonstrated that pruritus in PBC is associated with elevated serum total and glyco-conjugated BAs but no gut bacterial dysbiosis. Also, GSK2330672 was shown to reduce all taurine and glyco- conjugated serum BAs, increase faecal BAs and alter the gut-microbial composition. Taken together, the research studies presented in this thesis suggest: i) high prevalence of pruritus and its under-treatment in PBC, ii) removal of BAs by NBD or inhibition by IBAT inhibitor drug improves cholestatic pruritus and, iii) serum BAs but not gut microbiome are altered in cholestatic pruritus and they can be modified by IBAT inhibitor treatmentNational Institute for Health Research (NIHR), Newcastle Biomedical Research Centre (BRC

Apical Sodium-Dependent Transporter Inhibitors in Primary Biliary Cholangitis and Primary Sclerosing Cholangitis

Bile acids (BAs) have gained mainstream attention since the discovery of their key role as signalling molecules in health and disease. The apical sodium-dependent transporter (ASBT) protein located in the terminal ileum plays an important physiological role in the enterohepatic circulation of BAs and therefore essential for the BA homeostasis. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), the 2 most common cholestatic liver diseases are characterised by altered BA flow and BA composition, which contribute to disease progression and symptom (pruritus) development. Therefore, changing the circulating BA pool in patients with PBC and PSC may have therapeutic implications. To this end, pharmacological inhibition of ASBT is fast emerging as an interesting target. In this review, we discuss the recent evidence for potential therapeutic use of ASBT inhibitors to treat PBC and PSC patients.</jats:p

Autotaxin, bile acid profile and effect of ileal bile acid transporter inhibition in primary biliary cholangitis patients with pruritus

Background and Aims Pruritus is a common symptom in patients with primary biliary cholangitis (PBC) for which ileal bile acid transporter (IBAT) inhibition is emerging as a potential therapy. We explored the serum metabonome and gut microbiota profile in PBC patients with pruritus and investigated the effect of GSK2330672, an IBAT inhibitor. Methods We studied fasting serum bile acids (BAs), autotaxin and faecal microbiota in 22 PBC patients with pruritus at baseline and after 2 weeks of GSK2330672 treatment. Control group included 31 asymptomatic PBC patients and 18 healthy volunteers. BA profiling was done by ultra performance liquid chromatography coupled to a mass spectrometry (UPLC‐MS). Faecal microbiomes were analysed by 16S ribosomal RNA gene sequencing. Results \ud In PBC patients with pruritus, serum levels of total and glyco‐conjugated primary BAs and autotaxin were significantly elevated. Autotaxin activity correlated significantly with tauro‐ and glyco‐conjugated cholic acid (CA) and chenodeoxycholic acid (CDCA), both at baseline and after GSK2330672. GSK2330672 significantly reduced autotaxin and all tauro‐ and glyco‐ conjugated BAs and increased faecal levels of CA (P = 0.048) and CDCA (P = 0.027). Gut microbiota of PBC patients with pruritus was similar to control groups. GSK2330672 increased the relative abundance of Firmicutes (P = 0.033) and Clostridia (P = 0.04) and decreased Bacteroidetes (P = 0.033) and Bacteroidia (P = 0.04). Conclusions Pruritus in PBC does not show a distinct gut bacterial profile but is associated with elevated serum bile acid and autotaxin levels which decrease after IBAT inhibition. In cholestatic pruritus, a complex interplay between BAs and autotaxin is likely and may be modified by IBAT inhibition

UK-Wide Multicenter Evaluation of Second-line Therapies in Primary Biliary Cholangitis

Background &amp; aims: thirty-to-forty percent of patients with primary biliary cholangitis inadequately respond to ursodeoxycholic acid. Our aim was to assemble national, real-world data on the effectiveness of obeticholic acid (OCA) as a second-line treatment, alongside non-licensed therapy with fibric acid derivatives (bezafibrate or fenofibrate).Methods: this was a nationwide observational cohort study conducted from August 2017 until June 2021.Results: we accrued data from 457 patients; 349 treated with OCA and 108 with fibric acid derivatives. At baseline/pre-treatment, individuals in the OCA group manifest higher risk features compared with those taking fibric acid derivatives, evidenced by more elevated alkaline phosphatase values, and a larger proportion of individuals with cirrhosis, abnormal bilirubin, prior non-response to ursodeoxycholic acid, and elastography readings &gt;9.6kPa (P &lt; .05 for all). Overall, 259 patients (OCA) and 80 patients (fibric acid derivatives) completed 12 months of second-line therapy, yielding a dropout rate of 25.7% and 25.9%, respectively. At 12 months, the magnitude of alkaline phosphatase reduction was 29.5% and 56.7% in OCA and fibric acid groups (P &lt; .001). Conversely, 55.9% and 36.4% of patients normalized serum alanine transaminase and bilirubin in the OCA group (P &lt; .001). The proportion with normal alanine transaminase or bilirubin values in the fibric acid group was no different at 12 months compared with baseline. Twelve-month biochemical response rates were 70.6% with OCA and 80% under fibric acid treatment (P = .121). Response rates between treatment groups were no different on propensity-score matching or on sub-analysis of high-risk groups defined at baseline.Conclusion: across the population of patients with primary biliary cholangitis in the United Kingdom, rates of biochemical response and drug discontinuation appear similar under fibric acid and OCA treatment.</p

BAT117213:Ileal bile acid transporter (IBAT) inhibition as a treatment for pruritus in primary biliary cirrhosis: study protocol for a randomised controlled trial

BACKGROUND: Pruritus (itch) is a symptom commonly experienced by patients with cholestatic liver diseases such as primary biliary cholangitis (PBC, previously referred to as primary biliary cirrhosis). Bile acids (BAs) have been proposed as potential pruritogens in PBC. The ileal bile acid transporter (IBAT) protein expressed in the distal ileum plays a key role in the enterohepatic circulation of BAs. Pharmacological inhibition of IBAT with GSK2330672 may reduce BA levels in the systemic circulation and improve pruritus. METHODS: This clinical study (BAT117213 study) is sponsored by GlaxoSmithKline (GSK) with associated exploratory studies supported by the National Institute for Health Research (NIHR). It is a phase 2a, multi-centre, randomised, double bind, placebo controlled, cross-over trial for PBC patients with pruritus. The primary objective is to investigate the safety and tolerability of repeat doses of GSK2330672, and explore whether GSK2330672 administration for 14 days improves pruritus compared with placebo. The key outcomes include improvement in pruritus scores evaluated on a numerical rating scale and other PBC symptoms in an electronic diary completed twice daily by the patients. The secondary outcomes include the evaluation of the effect of GSK2330672 on total serum bile acid (BA) concentrations, serum markers of BA synthesis and steady-state pharmacokinetics of ursodeoxycholic acid (UDCA). DISCUSSION: BAT117213 study is the first randomised controlled crossover trial of ileal bile acid transporter inhibitor, a novel class of drug to treat pruritus in PBC. The main strengths of the trial are utility of a novel, study specific, electronic symptom diary as patient reported outcome to measure the treatment response objectively and the crossover design that allows estimating the treatment effect in a smaller number of patients. The outcome of this trial will inform the trial design of future development phase of the IBAT inhibitor drug. The trial will also provide opportunity to conduct metabonomic and gut microbiome studies as explorative and mechanistic research in patients with cholestatic pruritus. TRIAL REGISTRATION: EudraCT number: 2012-005531-84, ClinicalTrials.gov Identifier: NCT01899703, registered on 3(rd) July 201

The Serum Proteome and Ursodeoxycholic Acid Response in Primary Biliary Cholangitis.

Funder: UK‐PBC MRC Stratified MedicineFunder: Pfizer; Id: http://dx.doi.org/10.13039/100004319BACKGROUND AND AIMS: Stratified therapy has entered clinical practice in primary biliary cholangitis (PBC), with routine use of second-line therapy in nonresponders to first-line therapy with ursodeoxycholic acid (UDCA). The mechanism for nonresponse to UDCA remains, however, unclear and we lack mechanistic serum markers. The UK-PBC study was established to explore the biological basis of UDCA nonresponse in PBC and identify markers to enhance treatment. APPROACH AND RESULTS: Discovery serum proteomics (Olink) with targeted multiplex validation were carried out in 526 subjects from the UK-PBC cohort and 97 healthy controls. In the discovery phase, untreated PBC patients (n = 68) exhibited an inflammatory proteome that is typically reduced in scale, but not resolved, with UDCA therapy (n = 416 treated patients). Nineteen proteins remained at a significant expression level (defined using stringent criteria) in UDCA-treated patients, six of them representing a tightly linked profile of chemokines (including CCL20, known to be released by biliary epithelial cells (BECs) undergoing senescence in PBC). All showed significant differential expression between UDCA responders and nonresponders in both the discovery and validation cohorts. A linear discriminant analysis, using serum levels of C-X-C motif chemokine ligand 11 and C-C motif chemokine ligand 20 as markers of responder status, indicated a high level of discrimination with an AUC of 0.91 (CI, 0.83-0.91). CONCLUSIONS: UDCA under-response in PBC is characterized by elevation of serum chemokines potentially related to cellular senescence and was previously shown to be released by BECs in PBC, suggesting a potential role in the pathogenesis of high-risk disease. These also have potential for development as biomarkers for identification of high-risk disease, and their clinical utility as biomarkers should be evaluated further in prospective studies

Pulmonary complications of treatment with pegylated interferon for hepatitis C infection-Two case reports

Pegylated interferon (Peg-IFN) in combination with ribavirin is the standard of care in the treatment of chronic hepatitis C (HCV). Peg-IFN is known to have a number of side effects but severe respiratory complications are uncommon. We report two cases, one of Peg-IFN induced interstitial pneumonitis (IP) and the other of bronchiolitis obliterans organising pneumonia (BOOP) in patients with chronic hepatitis C infection. In general, respiratory complications of Peg-IFN are mild and resolve with withdrawal of Peg-IFN. However, as illustrated in our first case fatal interstitial pneumonitis can occur. We present a review of the available literature on Peg-IFN induced lung toxicity. In conclusion, pulmonary toxicity with Peg-IFN is rare but fatality can occur. We highlight the importance of maintaining a high index of suspicion for early diagnosis and prompt treatment, which includes withdrawal of Peg-IFN and consideration of corticosteroid treatment