PPAR agonists for the treatment of primary biliary cholangitis: Old and new tales

Evaluating the safety and efficacy of seladelpar for adults with primary biliary cholangitis

INTRODUCTION

Seladelpar (MBX-8025) is a once-daily administered highly specific PPAR-δ agonist in Phase 3 and extension trials for use in patients with primary biliary cholangitis (PBC).

AREAS COVERED

This review provides background on current treatment options for PBC, and summarizes clinical trial data regarding the safety and effectiveness of seladelpar within the context of these treatments.

EXPERT OPINION

Clinical trials results demonstrate the safety and tolerability of seladelpar use for PBC, including in patients with cirrhosis. The primary composite endpoint (ALP <1.67 times ULN, decrease ≥ 15% from baseline, and TB ≤ULN) was met in 61.7% of the patients treated with seladelpar and in 20% receiving placebo (p < 0.001). Moreover, pruritus - a cardinal and often intractable symptom of PBC - was improved with seladelpar treatment, as were overall quality of life measurements. Improvements in markers of inflammation were likewise observed. These biochemical and clinical findings therefore represent landmark developments in PBC treatment and offer a therapeutic option for PBC.

The treatment of primary biliary cholangitis: from shadow to light

Primary biliary cholangitis (PBC) is a chronic autoimmune cholestatic disease characterized by the destruction of the small intrahepatic bile ducts, which can progress to liver cirrhosis. The gold standard in the treatment of PBC is ursodeoxycholic acid (UDCA), which is indicated in all patients with PBC because it improves not only biochemical parameters but also patients' survival. An important milestone in the identification of patients at risk is the assessment of biochemical response to UDCA. Patients who respond to treatment have a lower incidence of hepatic events and better prognosis than patients who do not. Several scoring systems can be used to assess the response and identify non-responders who will benefit from second-line treatment. Obeticholic acid (OCA) is currently the only approved second-line treatment for PBC, which is effective for non-responders to UDCA therapy or patients, who have not tolerated UDCA therapy. However, OCA is contraindicated in advanced liver cirrhosis and portal hypertension. Moreover, pruritus may be a limiting factor for the administration of OCA. Fibrates have shown promising data supporting their use in non-responders to UDCA because they improve the biochemical parameters and elastographic findings and have possible antipruritic effects. Therefore, the idea of a triple treatment seems interesting. Clinical research is focusing on several other groups of drugs: peroxisome proliferator-activated receptor (PPAR) δ- and α/δ agonists, non-steroidal farnesoid X receptor agonists, fibroblast growth factor 19 modulators, and inhibitors of nicotinamide adenine dinucleotide phosphate oxidase 1 and 4.

PPARs in Clinical Experimental Medicine after 35 Years of Worldwide Scientific Investigations and Medical Experiments

This year marks the 35th anniversary of Professor Walter Wahli's discovery of the PPARs (Peroxisome Proliferator-Activated Receptors) family of nuclear hormone receptors. To mark the occasion, the editors of the scientific periodical Biomolecules decided to publish a special issue in his honor. This paper summarizes what is known about PPARs and shows how trends have changed and how research on PPARs has evolved. The article also highlights the importance of PPARs and what role they play in various diseases and ailments. The paper is in a mixed form; essentially it is a review article, but it has been enriched with the results of our experiments. The selection of works was subjective, as there are more than 200,000 publications in the PubMed database alone. First, all papers done on an animal model were discarded at the outset. What remained was still far too large to describe directly. Therefore, only papers that were outstanding, groundbreaking, or simply interesting were described and briefly commented on.

The overlap with metabolic dysfunction-associated steatotic liver disease negatively affects outcomes of primary biliary cholangitis

BACKGROUND AND AIMS

The relationship between primary biliary cholangitis (PBC) and metabolic dysfunction-associated steatotic liver disease, and its impact on treatment response and prognosis, remains underexplored.

METHODS

Patient cohort from two centres comprising long-term follow-up data. All patients had histologically confirmed PBC. Biopsies were classified according to Non-Alcoholic Steatohepatitis Clinical Research Network. Diagnosis of metabolic dysfunction-associated steatotic liver disease was established when steatosis exceeded 5%, along with at least one metabolic risk factor. Patients with specific aetiologies of steatosis, other liver diseases, incomplete results and inadequate treatment with ursodeoxycholic acid were excluded. Data from patients initiating second-line treatment were censored. Treatment response was assessed using the Toronto, Paris II and AST-to-platelet at 12-month criteria. The UK PBC and Globe scores, and liver events were utilized as outcome measures.

RESULTS

The study included 129 patients, 36 showing histologically confirmed overlap between PBC and steatosis. Patients with overlap showed worse prognosis according to Paris II (61.1% vs. 33.3%, p = 0.004), Toronto (52.5% vs. 24.7%, p = 0.002), AST-to-platelet 12-month >0.54 (36.1% vs. 17.2%, p = 0.021), Globe >0.30 (49.2% vs. 29.2%, p = 0.033) and UK PBC at 5, 10 and 15 years (p ≤ 0.001). Liver-related mortality and liver transplant were more prevalent in the overlap group (p = 0.001). In the multivariate analysis, steatosis, dyslipidaemia and advanced fibrosis were independently associated to worse outcomes.

CONCLUSIONS

Our findings suggest that metabolic dysfunction-associated steatotic liver disease worsens the prognosis of PBC.

Treatment in primary biliary cholangitis: Beyond ursodeoxycholic acid

Primary biliary cholangitis (PBC) is a rare cholestatic immune-mediated liver disease. The clinical course varies from mild to severe, with a substantial group of patients developing cirrhosis within a decade. These patients are at risk of hepatocellular carcinoma, decompensation and liver failure. First line Ursodeoxycholic acid (UDCA) treatment improves the cholestatic surrogate markers, and was recently associated with a favorable survival free of liver transplantation, even in case of an incomplete biochemical response. However, despite adequate UDCA therapy, patients remain at risk of liver disease progression. Therefore, on-treatment multifactor-based risk stratification is necessary to identify patients in need of additional therapy. This requires a personalized approach; especially as recent studies suggest that complete biochemical normalization as most stringent response criterion might be preferred in selected patients to optimize their outcome. Today, stricter biochemical goals might actually be reachable with the addition of farnesoid X receptor or peroxisome proliferator-activated receptor agonists, or, in highly-selected cases, use of corticosteroids. Randomized controlled trials showed improvements in the key biochemical surrogate markers with the addition of these drugs, which have also been associated with improved clinical outcome. Considering this evolving PBC landscape, with more versatile treatment options and treatment goals, this review recapitulates the recent insight in UDCA therapy, the selection of patients with a residual risk of liver disease progression and the results of the currently available second line treatment options.

Frequency of antithyroid antibodies in patients with primary biliary cholangitis

OBJECTIVE

Primary biliary cholangitis (PBC) is an autoimmune disease of liver that may be associated with other conditions, including autoimmune thyroid diseases. We aimed to investigate the frequency of anti-thyroperoxidase antibodies (TPO-Ab), antithyroglobulin antibodies (TG-Ab), and anti-thyrotropin receptor antibodies (TSHR-Ab) in Tunisian patients with PBC.

METHODS

Sera of 80 patients with PBC were collected over a 9-year period. A total of 189 healthy blood donors (HBD) were included in the control group. Measurements of TPO-Ab and TG-Ab were performed using indirect enzyme-linked immunosorbent assay (ELISA). Competitive ELISA was used to assess TSHR-Ab.

RESULTS

Antithyroid antibodies (ATA) were significantly more frequent in PBC patients than in the control group (13.7% vs 1.6%; P < 10-3). Out of 11 patients with ATA, 10 (90.9%) were female. Nine patients and 2 HBD had TPO-Ab (11.2% vs 1%; P < 10-3). TG-Ab were more frequent in patients than in healthy subjects but the difference was not statistically significant (6.2% vs 1.6%; P = .1). TPO-Ab and TG-Ab were present together in 3 patients (3.7%). TSHR-Ab were absent in patients and controls.

CONCLUSION

This study shows that PBC is associated with a high frequency of ATA but not TG-Ab or TSHR-Ab.

[Primary biliary cholangitis-response criteria of first-line treatment and perspectives of second-line therapy]

BACKGROUND

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease that can progress to liver cirrhosis if left untreated. Early diagnosis, initiation of therapy and, if necessary, adjustment of treatment are essential to prevent disease progression. The timing and thresholds for assessing adequate treatment response are inconsistently defined in the literature and can pose a challenge in clinical practice.

OBJECTIVE

In addition to providing a concise overview of the guideline-based diagnostic work-up and first-line therapy, this study offers practical guidance for the evaluation of treatment response and options for second-line treatment in PBC.

MATERIALS AND METHODS

This article is based on the current European Association for the Study of the Liver (EASL) clinical practice guidelines for the management of PBC from 2017 as well as a literature review of studies from 2017 to 2023, focusing on defining treatment response, assessing disease progression risk, and the approved and investigational agents for second-line therapy.

RESULTS

There are varying definitions for a sufficient response to ursodeoxycholic acid (UDCA). Therapeutic goals are tailored to the individual risk of disease progression. The lowest risk appears to be associated with normalization of alkaline phosphatase (AP) and serum bilirubin below 0.6 the upper limit of normal. Established second-line therapies include obeticholic acid and bezafibrate (off-label use), while other peroxisome proliferator-activated receptor (PPAR) agonists and combination therapies are under clinical investigation.

DISCUSSION

Early evaluation of treatment response to UDCA is mandatory. In the case of insufficient treatment response, second-line therapy should be initiated according to the individual's risk profile.

The role of peroxisome proliferator-activated receptors in the regulation of bile acid metabolism

Bile acids are synthesized from cholesterol in the liver. Dysregulation of bile acid homeostasis, characterized by excessive accumulation in the liver, gallbladder and blood, can lead to hepatocellular damage and the development of cholestatic liver disease. Nuclear receptors play a crucial role in the control of bile acid metabolism by efficiently regulating bile acid synthesis and transport in the liver. Among these receptors, peroxisome proliferator-activated receptor (PPAR), a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily, controls the expression of genes involved in adipogenesis, lipid metabolism, inflammation and glucose homeostasis and has emerged as a potential therapeutic target for the treatment of the metabolic syndrome in the past two decades. Emerging evidence suggests that PPAR activation holds promise as a therapeutic target for cholestatic liver disease, as it affects both bile acid production and transport. This review provides a comprehensive overview of recent advances in elucidating the role of PPAR in the regulation of bile acid metabolism, highlighting the current position of PPAR agonists in the treatment of primary biliary cholangitis. By summarizing the specific regulatory effects of PPAR on bile acids, this review contributes to the exploration of novel therapeutic strategies for cholestatic liver diseases.

Treatment of Primary Biliary Cholangitis including Transplantation

Ursodeoxycholic acid (UDCA) is the first-line treatment of primary biliary cholangitis (PBC). Long-term UDCA use significantly reduces progression to cirrhosis. UDCA improves liver enzymes and transplant-free survival rates. Despite the association between PBC and hyperlipidemia, treatment is indicated under specific circumstances with statins and fibrates being safe options. Osteoporosis, which is frequently seen, is usually managed based on data from postmenopausal women. Sicca syndrome is treated similarly to its standalone condition with the use of hydroxypropyl methylcellulose eye drops and anticholinergic drugs.

New Therapies on the Horizon for Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease that can progress to cirrhosis and hepatic failure if left untreated. Ursodeoxycholic acid (UDCA) was introduced as a first-line drug for PBC around 1990; it remarkably improved patient outcomes, leading to the nomenclature change of PBC in 2015, from primary biliary "cirrhosis" to primary biliary "cholangitis." Nevertheless, 20-30% of patients exhibit an incomplete response to UDCA, resulting in significantly worse outcomes compared to those with a complete response. Therefore, improving the long-term outcomes of patients with an incomplete response to UDCA has been recognized as an unmet need. In addition, patients with PBC often suffer from a variety of debilitating symptoms, such as pruritus, fatigue and sicca syndrome, which significantly impair their health-related quality of life. Thus, appropriate management of these symptoms is currently regarded as another unmet need for PBC treatment. In this review, several compounds and drugs under clinical trials that can potentially solve these unmet needs are comprehensively discussed, and future directions of treatment policy of PBC are proposed for significantly improving long-term outcome as well as health-related quality of life of patients.

Determinants of the effectiveness of bezafibrate combined with ursodeoxycholic acid in patients with primary biliary cholangitis

BACKGROUND AND AIMS

For patients with primary biliary cholangitis (PBC) exhibiting suboptimal responses to ursodeoxycholic acid (UDCA), obeticholic acid (OCA), and bezafibrate (BZF) are currently used and shown to improve long-term outcomes. Nevertheless, we encounter patients who die or undergo liver transplantation (LT) even with combination treatment. In this study, we explored prognostic indicators in patients receiving combination treatment of UDCA and BZF.

METHODS

We took advantage of the Japanese PBC registry and enrolled patients who received both UDCA and BZF therapy in 2000 or later. The covariates investigated included baseline covariates as well as treatment covariates. Two main outcomes (all-cause death or LT and liver-related death or LT) were assessed using multivariable-adjusted Cox proportional hazards models.

RESULTS

In total, 772 patients were included. The median follow-up was 7.1 years. Using the Cox regression model, bilirubin (hazard ratio [HR] 6.85, 95% confidence interval [CI] 1.73-27.1, p = 0.006), alkaline phosphatase (HR 5.46, 95% CI 1.32-22.6, p = 0.019), and histological stage (HR 4.87, 95% CI 1.16-20.5, p = 0.031) were found associated with LT-free survival. For survival free from liver disease-related death or LT, albumin (HR 7.72, 95% CI 1.48-40.4, p = 0.016) and bilirubin (HR 14.5, 95% CI 2.37-88.5, p = 0.004) were found significantly associated.

CONCLUSION

In patients with PBC receiving combination therapy, prognostic variables were similar to those in patients receiving UDCA monotherapy. These results indicate the importance of diagnosing patients with PBC at an earlier stage because of the reduced effectiveness of BZF at advanced stages.

Current Therapies for Cholestatic Diseases

Cholestasis is a condition characterized by decrease in bile flow due to progressive pathological states that lead to chronic cholestatic liver diseases which affect the biliary tree at the intrahepatic level and extrahepatic level. They induce complications such as cirrhosis, liver failure, malignancies, bone disease and nutritional deficiencies that merit close follow-up and specific interventions. Furthermore, as those conditions progress to liver cirrhosis, there will be an increase in mortality but also an important impact in quality of life and economic burden due to comorbidities related with liver failure. Therefore, it is important that clinicians understand the treatment options for cholestatic liver diseases. With a general view of therapeutic options and their molecular targets, this review addresses the pathophysiology of cholangiopathies. The objective is to provide clinicians with an overview of the safety and efficacy of the treatment of cholangiopathies based on the current evidence.