Low risk of hepatotoxicity from rifampicin when used for cholestatic pruritus: a cross-disease cohort study

Sodium/bile acid co-transporter inhibitors currently in preclinical or early clinical development for the treatment of primary biliary cholangitis

INTRODUCTION

Pruritus is common and often undertreated in patients with primary biliary cholangitis (PBC). Existing treatments largely have an aging and low-quality evidence base, and studies included only small numbers of patients. More recent data that has added to our understanding of pruritus treatments has often come from clinical trials where itching was a secondary outcome measure in a trial designed primarily to assess disease-modifying agents. This area represents an unmet clinical need in the management of PBC.

AREAS COVERED

In this manuscript, we first summarize the proposed mechanisms for PBC-related pruritus and the current treatment paradigm. We then present an appraisal of the existing pre-clinical and clinical evidence for the use of ileal bile acid transporter inhibitors (IBATis) for this indication in PBC patients.

EXPERT OPINION

Evidence for the efficacy of IBATis is promising but limited by the currently available volume of data. Furthermore, larger clinical trials with long-term data on efficacy, safety and tolerability are needed to confirm the role of using IBATis in clinical practice and their place on the itch treatment ladder. Additional focus should also be given to exploring the disease-modifying potential of IBATis in PBC.

EASL Clinical Practice Guidelines on the management of liver diseases in pregnancy

Liver diseases in pregnancy comprise both gestational liver disorders and acute and chronic hepatic disorders occurring coincidentally in pregnancy. Whether related to pregnancy or pre-existing, liver diseases in pregnancy are associated with a significant risk of maternal and fetal morbidity and mortality. Thus, the European Association for the Study of Liver Disease invited a panel of experts to develop clinical practice guidelines aimed at providing recommendations, based on the best available evidence, for the management of liver disease in pregnancy for hepatologists, gastroenterologists, obstetric physicians, general physicians, obstetricians, specialists in training and other healthcare professionals who provide care for this patient population.

New Treatment Paradigms in Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an archetypal autoimmune disease. Chronic lymphocytic cholangitis is associated with interface hepatitis, ductopenia, cholestasis, and progressive biliary fibrosis. People living with PBC are frequently symptomatic, experiencing a quality-of-life burden dominated by fatigue, itch, abdominal pain, and sicca complex. Although the female predominance, specific serum autoantibodies, immune-mediated cellular injury, as well as genetic (HLA and non-HLA) risk factors, identify PBC as autoimmune, to date treatment has focused on cholestatic consequences. Biliary epithelial homeostasis is abnormal and contributes to disease. The impact of cholangiocyte senescence, apoptosis, and impaired bicarbonate secretion enhances chronic inflammation and bile acid retention. First-line therapy is a non-specific anti-cholestatic agent, ursodeoxycholic acid. For those with residual cholestasis biochemically, obeticholic acid is introduced, and this semisynthetic farnesoid X receptor agonist adds choleretic, anti-fibrotic, and anti-inflammatory activity. Future PBC licensed therapy will likely include peroxisome proliferator activated receptor (PPAR) pathway agonists, including specific PPAR-delta agonism (seladelpar), as well as elafibrinor and saroglitazar (both with broader PPAR agonism). These agents dovetail the clinical and trial experience for off-label bezafibrate and fenofibrate use. Symptom management is essential, and encouragingly, PPAR agonists reduce itch; IBAT inhibition (eg, linerixibat) also appears promising for pruritus. For those where liver fibrosis is the target, NOX inhibition is being evaluated. Earlier stage therapies in development include therapy to impact immunoregulation in patients, as well other approaches to treating pruritus (eg, antagonists of MrgprX4). Collectively the PBC therapeutic landscape is exciting. Therapy goals are increasingly proactive and individualized and aspire to rapidly achieve normal serum tests and quality of life with prevention of end-stage liver disease.

Primary biliary cholangitis: Epidemiology, prognosis, and treatment

Primary biliary cholangitis (PBC) is a chronic cholestatic autoimmune liver disease characterized by a destructive, small duct, and lymphocytic cholangitis, and marked by the presence of antimitochondrial antibodies. The incidence and prevalence of PBC vary widely in different regions and time periods, and although disproportionally more common among White non-Hispanic females, contemporary data show a higher prevalence in males and racial minorities than previously described. Outcomes largely depend on early recognition of the disease and prompt institution of treatment, which, in turn, are directly influenced by provider bias and socioeconomic factors. Ursodeoxycholic acid remains the initial treatment of choice for PBC, with obeticholic acid and fibrates (off-label therapy) reserved as add-on therapy for the management of inadequate responders or those with ursodeoxycholic acid intolerance. Novel and repurposed drugs are currently at different stages of clinical development not only for the treatment of PBC but also for its symptomatic management. Here, we summarize the most up-to-date data regarding the epidemiology, prognosis, and treatment of PBC, providing clinically useful information for its holistic management.

Cholestatic Pruritus Treatments in Primary Biliary Cholangitis and Primary Sclerosing Cholangitis: A Systematic Literature Review

BACKGROUND AND AIMS

We conducted a systematic literature review to understand the evidence supporting treatment decisions for cholestatic pruritus associated with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC).

METHODS

Studies that enrolled ≥ 75% participants with PBC or PSC and reported ≥ 1 endpoint(s) related to efficacy, safety, health-related quality of life (HRQoL) or other patient-reported outcomes were included. Bias was assessed using the Cochrane risk of bias tool for randomised controlled trials (RCTs) and the Quality of Cohort studies tool for non-RCTs.

RESULTS

Thirty-nine publications were identified, covering 42 studies and six treatment classes (including investigational and approved products): anion-exchange resins, antibiotics (rifampicin/derivatives), opiates, selective serotonin reuptake inhibitors, fibrates, ileal bile acid transporter inhibitors and other agents not categorised in these six classes. Across studies, median sample size was small (n = 18), 20 studies were over 20 years old, 25 followed patients for ≤ 6 weeks, only 25 were RCTs. Pruritus was assessed using several different tools, with inconsistencies in their application. Cholestyramine, considered first-line therapy for moderate-severe cholestatic pruritus, was assessed in six studies (two RCTs) including 56 patients with PBC and 2 with PSC, with evidence of efficacy demonstrated in only three studies, among which, two RCTs were assessed as having a high risk of bias. Findings were similar for other drug classes.

CONCLUSIONS

There is a lack of consistent and reproducible evidence available on efficacy, impact on HRQoL, and safety of cholestatic pruritus treatments, leaving physicians to rely on clinical experience rather than evidence-based medicine for treatment selection.

Guidelines for the Management of Cholestatic Liver Diseases (2021)

In 2015, the Chinese Society of Hepatology and the Chinese Society of Gastroenterology issued a consensus statement on the diagnosis and management of cholestatic liver diseases. More clinical data on this topic have appeared during recent years. The Autoimmune Liver Disease Group of the Chinese Society of Hepatology organized an expert group to review recent evidence and provide an update to these previous guidelines. Herein, we provide 22 recommendations as a working reference for the management of cholestatic liver diseases by clinical practitioners.

[Systemic pruritus: what is new in diagnosis and treatment?]

BACKGROUND

Chronic pruritus is a common symptom of various systemic diseases. In particular, patients with chronic renal failure, hepatobiliary diseases, and myeloproliferative neoplasms are affected.

OBJECTIVES

The purpose of this review is to provide an overview of laboratory chemistry and imaging diagnostics as well as current and novel therapeutic approaches to pruritus of systemic diseases.

MATERIALS AND METHODS

An extensive PubMed search was performed.

RESULTS

To clarify the cause of chronic pruritus, a step-by-step diagnosis is recommended, which is based on the frequency of pruritus-associated diseases. A basic diagnosis enables a cost-effective and targeted clarification at the level of a general practitioner. Current topical and drug therapy recommendations of pruritus in chronic renal failure, hepatobiliary diseases, myeloproliferative neoplasms, and rarer causes are summarized. In addition, novel therapeutic approaches such as the κ‑opioid receptor agonist difelikefalin, bezafibrate, inhibitors of the ileal bile acid transporter (IBAT), and the JAK-STAT pathway are highlighted.

CONCLUSIONS

Chronic pruritus in systemic diseases can be a diagnostic challenge. A staged diagnostic approach facilitates identification of the underlying disease. Improved pathophysiological understanding has led to the first approved therapeutic options for chronic kidney disease-associated and hepatic pruritus.

Efficacy and safety of rifampicin in patients with persistent hepatocellular secretory failure

BACKGROUND AND AIM

Persistent hepatocellular secretory failure (PHSF) is a rare condition of severe cholestasis caused by drugs, toxins, infection, or temporary biliary obstruction. Real-world data on rifampicin in cholestasis, particularly among patients with deep jaundice, are scarce. We aimed to expand the knowledge on the efficacy and safety of rifampicin treatment in PHSF patients.

METHODS

Sixteen patients with PHSF who had received rifampicin treatment (150-300 mg/d) at our institution from September 2016 to July 2020 were included. Treatment efficacy was assessed by 20% improvement in serum total bilirubin (TBIL) concentration at 4 weeks. Follow-up was continued until the concentration of TBIL returned to normal.

RESULTS

Among the 16 enrolled patients, 12 had predisposing factors (drugs, infection, or transient biliary obstruction). ATP8B1 or ABCB11 mutations were detected in the other four patients without trigger events. UGT1A1 mutations were found in 7/10 patients. Before rifampicin treatment, the median TBIL level was 352 μmol/L (range 171-591 μmol/L). TBIL > 20% improvement was observed in 14 patients at 4 weeks. TBIL levels of 14 patients eventually returned to normal after 6-12 weeks of rifampicin treatment. The remaining two patients who did not respond to rifampicin finally recovered after nasobiliary drainage. Except for one patient with transient drug-induced hepatitis, no other serious adverse events were observed.

CONCLUSIONS

Rifampicin could be a promising option for most PHSF patients. Most PHSF patients have UGT1A1 deficiency, which may be the target of rifampicin.

Use of Butorphanol as Treatment for Cholestatic Itch

BACKGROUND

Pruritus is a debilitating symptom of cholestatic diseases such as primary biliary cholangitis and primary sclerosing cholangitis and often results in major reduction in quality of life for afflicted patients. Classic treatment options for the treatment of cholestatic pruritus include antihistamines, bile acid resins, serotonin reuptake inhibitors, and mu-opioid antagonists. Unfortunately, these drugs are not always successful in treating pruritus of cholestasis and may be associated with adverse effects. Recent advances in our understanding of itch pathophysiology have led to the use of butorphanol, a kappa-opioid agonist and mu-opioid antagonist, for the treatment of various forms of pruritus. Reports of butorphanol to treat cholestatic itch specifically are rare.

AIMS

To better understand the role of butorphanol in the treatment of cholestatic pruritus, including characterization of its side effect profile.

METHODS

We present a case series of eight adult patients with cholestatic disease who were treated with butorphanol in hopes of alleviating intractable pruritus. Patients were identified through a clinical data request form serviced by University of Miami Information Technology.

RESULTS

Five out of eight patients (62.5%) reported successful reductions in itch severity after treatment with butorphanol, two patients reported no (or transient) change in itch severity, and one patient reported a paradoxical increase in itching. Side effects included somnolence, sedation, nausea, vomiting, and dizziness.

CONCLUSIONS

Butorphanol was safe and leads to clinically significant symptomatic improvement. Clinicians should be aware of butorphanol as an off-label treatment option for pruritus of cholestasis. Further studies are needed to better characterize the effect of butorphanol on cholestatic itch.

Safety considerations for the management of cholestatic itch

Introduction: Pruritus is adisabling symptom common to cholestatic liver disorders. Its pathophysiology has not been completely elucidated and although multiple mediators have been identified, only lysophosphatidic acid (LPA) and its synthetizing enzyme autotaxin (ATX) appear to consistently correlate with symptom intensity. This review aims to summarize the most relevant safety and efficacy data regarding both standard and new medications utilized to treat pruritus in cholestatic liver disease.Areas covered: International societies like the AASLD and EASL recommend astepwise approach for the management of cholestatic itch. However, therapeutic response is variable. Cholestyramine is considered first-line, followed by rifampicin, naltrexone and sertraline. When used appropriately, these medications have afavorable adverse events profile with most side effects related to drug class and not to the underlying etiology of liver disease.Expert opinion: Although conventional therapies seem to be effective in aproportion of patients, asizable number of cases remain refractory and require the utilization of experimental treatments. Multiple potential targets, especially in the ATX-LPA axis have yet to be pharmacologically explored, with ongoing translational and clinical research. Novel drugs are currently being developed for the management of cholestatic itching with promising results and afavorable safety profile.

Compensatory Transition of Bile Acid Metabolism from Fecal Disposition of Secondary Bile Acids to Urinary Excretion of Primary Bile Acids Underlies Rifampicin-Induced Cholestasis in Beagle Dogs

Drug induced cholestasis (DIC) is complexly associated with dysbiosis of the host-gut microbial cometabolism of bile acids (BAs). Murine animals are not suitable for transitional studies because the murine BA metabolism is quite different from human metabolism. In this work, the rifampicin (RFP) induced cholestasis was established in beagle dogs that have a humanlike BA profile to disclose how RFP affects the host-gut microbial cometabolism of BAs. The daily excretion of BA metabolites in urine and feces was extensively analyzed during cholestasis by quantitative BA profiling along the primary-secondary-tertiary axis. Oral midazolam clearance was also acquired to monitor the RFP-induced enterohepatic CYP3A activities because CYP3A is exclusively responsible for the tertiary oxidation of hydrophobic secondary BAs. RFP treatments caused a compensatory transition of the BA metabolism from the fecal disposition of secondary BAs to the urinary excretion of primary BAs in dogs, resulting in an infantile BA metabolism pattern recently disclosed in newborns. However, the tertiary BAs consistently constituted limitedly in the daily BA excretion, indicating that the detoxification role of the CYP3A catalyzed tertiary BA metabolism was not as strong as expected in this model. Multiple host-gut microbial factors might have contributed to the transition of the BA metabolism, such as inhibition of BA transporters, induction of liver-kidney interplaying detoxification mechanisms, and elimination of gut bacteria responsible for secondary BA production. Transitional studies involving more cholestatic drugs in preclinical animals with a humanlike BA profile and DIC patients may pave the way for understanding the complex mechanism of DIC in the era of metagenomics.

Primary biliary cholangitis

Primary biliary cholangitis is an autoimmune liver disease that predominantly affects women. It is characterised by a chronic and destructive, small bile duct, granulomatous lymphocytic cholangitis, with typical seroreactivity for antimitochondrial antibodies. Patients have variable risks of progressive ductopenia, cholestasis, and biliary fibrosis. Considerations for the cause of this disease emphasise an interaction of chronic immune damage with biliary epithelial cell responses and encompass complex, poorly understood genetic risks and environmental triggers. Licensed disease-modifying treatment focuses on amelioration of cholestasis, with weight-dosed oral ursodeoxycholic acid. For patients who do not respond sufficiently, or patients with ursodeoxycholic acid intolerance, conditionally licensed add-on therapy is with the FXR (NR1H4) agonist, obeticholic acid. Off-label therapy is recognised as an alternative, notably with the pan-PPAR agonist bezafibrate; clinical trial agents are also under development. Baseline characteristics, such as young age, male sex, and advanced disease, and serum markers of liver injury, particularly bilirubin and ALP, are used to stratify risk and assess treatment responsiveness. Parallel attention to the burden of patient symptoms is paramount, including pruritus and fatigue.

Rifampicin for Treatment of Cholestatic Pruritus Caused by Drug-Induced Acute Liver Injury as Assessed by the RUCAM Classification

A male bodybuilder of 39 years of age developed severe pruritus, nausea, and jaundice after injecting anabolic steroids purchased on the black market. The patient had no history of liver disease and no risk factors for viral hepatitis. Extensive laboratory testing, radiographic imaging, and liver biopsy excluded a majority of potential pathologies. The patient was diagnosed with drug-induced acute liver injury and secondary acute renal failure most likely caused by testosterone purchased on the black market. The pruritus caused insomnia and significant psychological distress. Treatment was initiated with cholestyramine and naltrexone for one week with no effect on the pruritus. Subsequently, all medications were stopped, and rifampicin was started. Pruritus resolved after starting rifampicin, and liver and kidney function improved rapidly and normalized within 5 months.

Drug-Induced Liver Injury in the Setting of Chronic Liver Disease

Drug-induced liver injury (DILI) is an uncommon but significant cause of liver injury and need for liver transplant. DILI in the setting of chronic liver disease (CLD) is poorly understood. Clinical features of patients presenting with DILI in the setting of CLD are similar to those without CLD with the exception of a higher incidence of diabetes among those with CLD and DILI. Diagnosis of DILI in CLD is difficult because there are no objective biomarkers and current causality assessments have not been studied in this population. Differentiating DILI from exacerbation of underlying liver disease is even more challenging.

[Primary biliary cholangitis-established and novel therapies]

BACKGROUND

Patients with primary biliary cholangitis (PBC, formerly primary biliary cirrhosis) and insufficient treatment response or risk factors exhibit a remarkably increased risk for disease progression and associated complications. Furthermore, extrahepatic manifestations may considerably reduce quality of life in affected patients.

OBJECTIVES

This article presents an overview on standard therapy with ursodeoxycholic acid (UDCA) and further therapeutic options in patients with insufficient treatment response. In addition, symptom-orientated therapies will be presented in a practical and compact way.

METHODS

The current European and German guidelines from 2017 in addition to several research papers and expert opinions are the basis for this review.

RESULTS

Every PBC patient should be treated with UDCA life-long. In case of insufficient response to UDCA, obeticholic acid (OCA) has been approved as second line therapy since 2016. Fibrates and budesonide present off-label options for certain patient subpopulations. Pruritus should initially be treated with colestyramine. In case of insufficient efficacy or intolerance, rifampicin represents the most effective off-label option. If fatigue is present, differential diagnoses shall be excluded and coping strategies combined with regular physical activity can have a positive effect.

CONCLUSION

UDCA and OCA are effective and approved drugs for treating PBC. Patients with insufficient treatment response or risk factors have to be treated consequently. Due to the improved anti-cholestatic treatment options, therapies to reduce fatigue and pruritus are increasingly important.

Treatment of Pruritus Secondary to Liver Disease

PURPOSE OF REVIEW

Pruritus is a common extrahepatic symptom in various liver disorders, in particularly those with cholestatic features. This review summarizes epidemiology, pathophysiology, evidence-based therapeutic recommendations and currently investigated drugs for pruritus in hepatobiliary disorders.

RECENT FINDINGS

Recent epidemiological data suggest pruritus as a common and relevant symptom in immune-mediated liver diseases, i.e., primary biliary cholangitis (PBC) with over 70% affected patients, up to 56% suffering from chronic pruritus. The better pathophysiological understanding of hepatic pruritus has led to the identification of novel therapeutic targets, addressed in drug trials using KOR agonists, PPAR agonists, and ileal bile acid transporter inhibitors. Hepatic itch remains among the most agonizing symptoms for affected patients and a clinical challenge for physicians. Therapeutic recommendations include a guideline-based stepwise approach starting with cholestyramine, followed by rifampicin, naltrexone, and sertraline. Bezafibrate and ileal bile acid transporter inhibitors represent promising future anti-pruritic treatment options.

Mathematical Models in the Description of Pregnane X Receptor (PXR)-Regulated Cytochrome P450 Enzyme Induction

The pregnane X receptor (PXR) is a drug/xenobiotic-activated transcription factor of crucial importance for major cytochrome P450 xenobiotic-metabolizing enzymes (CYP) expression and regulation in the liver and the intestine. One of the major target genes regulated by PXR is the cytochrome P450 enzyme (CYP3A4), which is the most important human drug-metabolizing enzyme. In addition, PXR is supposed to be involved both in basal and/or inducible expression of many other CYPs, such as CYP2B6, CYP2C8, 2C9 and 2C19, CYP3A5, CYP3A7, and CYP2A6. Interestingly, the dynamics of PXR-mediated target genes regulation has not been systematically studied and we have only a few mechanistic mathematical and biologically based models describing gene expression dynamics after PXR activation in cellular models. Furthermore, few indirect mathematical PKPD models for prediction of CYP3A metabolic activity in vivo have been built based on compartmental models with respect to drug–drug interactions or hormonal crosstalk. Importantly, several negative feedback loops have been described in PXR regulation. Although current mathematical models propose these adaptive mechanisms, a comprehensive mathematical model based on sufficient experimental data is still missing. In the current review, we summarize and compare these models and address some issues that should be considered for the improvement of PXR-mediated gene regulation modelling as well as for our better understanding of the quantitative and spatial dynamics of CYPs expression.