New therapeutics in primary biliary cirrhosis: will there ever be light?

An Update on the Treatment and Follow-up of Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by chronic granulomatous lymphocytic cholangitis of the small bile ducts. PBC was a leading indication for liver transplant in the United States; with early diagnosis and treatment, the majority of patients with PBC have a normal life expectancy. Pathogenesis involves inflammatory damage of bile duct epithelium secondary to innate and adaptive immune responses, and toxicity from accumulated bile acids. Cholestasis and disease progression can lead to cirrhosis. Extrahepatic complications include dyslipidemia, metabolic bone disease, and fat-soluble vitamin deficiency. Ursodeoxycholic acid is a well-established therapy. Novel targeted therapeutics are being developed.

New developments in the treatment of primary biliary cholangitis - role of obeticholic acid

Primary biliary cholangitis (PBC) is a chronic autoimmune cholestatic liver disease that predominantly affects women in early to middle age. It is typically associated with autoantibodies to mitochondrial antigens and results in immune-mediated destruction of small and medium-sized intrahepatic bile ducts leading to cholestasis, hepatic fibrosis and may progress to cirrhosis or hepatic failure and, in some cases, hepatocellular carcinoma. The clinical presentation and the natural history of PBC have improved over the years due to recognition of earlier widespread use of ursodeoxycholic acid (UDCA); about one-third of patients show suboptimal biochemical response to UDCA with poor prognosis. Until recently, UDCA was the only US Food and Drug Administration approved agent for this disease for more than two decades; obeticholic acid was approved in 2016 for treatment of patients with PBC with a suboptimal response or intolerance to UDCA. Currently, liver transplantation is the most effective treatment modality for PBC patients with end-stage liver disease. This review will focus on the recent advances in therapy of primary biliary cholangitis, with emphasis on obeticholic acid.

Unmet challenges in immune-mediated hepatobiliary diseases

It is ironic that the liver, which serves a critical function in immune tolerance, itself becomes the victim of an autoimmune attack. Indeed, liver autoimmunity and the autoimmune diseases associated with both innate and adaptive responses to hepatocytes and/or cholangiocytes are models of human autoimmunity. For example, in primary biliary cirrhosis, there exists a well-defined and characteristic autoantibody and considerable homogeneity between patients. In autoimmune hepatitis, there are clinical characteristics that allow a rigorous subset definition and well-defined inflammatory infiltrates. In both cases, there are defects in a variety of immune pathways and including regulatory cells. In primary sclerosing cholangitis, with its characteristic overlap with inflammatory bowel disease, there are unique defects in innate immunity and particular important contribution of lymphoid homing to disease pathogenesis. In these diseases, as with other human autoimmune processes, there is the critical understanding that pathogenesis requires a genetic background, but is determined by environmental features, and indeed the concordance of these diseases in identical twins highlights the stochastic nature of immunopathology. Unfortunately, despite major advances in basic immunology and in immunopathology in these diseases, there remains a major void in therapy. The newer biologics that are so widely used in rheumatology, neurology, and gastroenterology have not yet seen success in autoimmune liver disease. Future efforts will depend on more rigorous molecular biology and systems analysis in order for successful application to be made to patients.

The coexistence of Sjögren's syndrome and primary biliary cirrhosis: a comprehensive review

Organ-specific and systemic autoimmune diseases share numerous features and often coexist in the same patient. Autoimmune cholangitis/primary biliary cirrhosis and Sjogren syndrome represent paradigmatic examples of the common grounds of different autoimmunity phenotypes based on similarities in clinical manifestations and immunopathogenesis. In fact, primary biliary cirrhosis and Sjogren's syndrome have both been coined as an autoimmune epithelitis in which apoptosis may be in both cases the key element to explain the organ-specific immune-mediated injury against the biliary and exocrine gland epithelia, respectively. Further, growing evidence supports in both diseases the view that B cells, T cytotoxic cells, and T helper cells are involved in chronic inflammation, likely via the altered expression of pro-inflammatory cytokines. The presence of estrogen receptors on the biliary and exocrine gland epithelia has been advocated as a key to the female predominance encountered in primary biliary cirrhosis and Sjogren's syndrome. Sadly, despite available data, therapeutic approaches remain largely unsatisfactory and recent studies with mechanistic approaches (as in the case of B cell depletion with rituximab) have been of partial benefit only. Future studies should focus on new molecular tools (single-cell transcriptomics, microRNA, epigenetics) to provide unique insights into common mechanisms.

Obeticholic acid for the treatment of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is characterized by progressive nonsuppurative destruction of small bile ducts, resulting in intrahepatic cholestasis, fibrosis and ultimately end-stage liver disease. Timely intervention with ursodeoxycholic acid is associated with excellent survival, although approximately one-third of all patients fail to achieve biochemical response, signifying a critical need for additional therapeutic strategies. Obeticholic acid (OCA) is a potent ligand of the nuclear hormone receptor farnesoid X receptor (FXR). Activation of FXR inhibits bile acid synthesis and protects against toxic accumulation in models of cholestasis and facilitates hepatic regeneration in preclinical studies. Data from recent Phase II and III controlled trials suggest a therapeutic impact of OCA in PBC biochemical nonresponders, as evidenced by change in proven laboratory surrogates of long-term outcome. Dose-dependent pruritus is a common adverse effect, but may be overcome through dose-titration. Longer term studies are needed with focus on safety and long-term clinical efficacy.

Biochemical responses to bezafibrate improve long-term outcome in asymptomatic patients with primary biliary cirrhosis refractory to UDCA

BACKGROUND

Bezafibrate is reported to have biochemical efficacy for patients with primary biliary cirrhosis (PBC) refractory to ursodeoxycholic acid (UDCA), yet the long-term effect is still unknown. In Japan, nationwide surveys of PBC have been performed since 1980. In the current study, we retrospectively examined whether response to bezafibrate treatment is associated with the long-term outcomes using this large-scale database.

METHODS

Among 7,376 patients in the database, we enrolled patients who were treated with UDCA at 13-15 mg/kg per day and followed up for at least 2 years after diagnosis. Bezafibrate (400 mg/day) was administered in addition to UDCA when biochemical response to UDCA was not optimal. Response to bezafibrate treatment was determined by serum alanine transaminase (ALT) levels within 2-3 years or at the earliest point thereafter from the commencement of bezafibrate treatment.

RESULTS

We enrolled 1,121 PBC patients, and the observational period was 6.1 ± 3.4 years. Among the PBC patients, 835 were asymptomatic, defined as no liver-related symptoms at the baseline. In asymptomatic PBC patients, multivariate analysis indicated that ALT response to bezafibrate treatment was significantly associated with the presence of liver-related symptoms at the end of observation [hazard ratio 1.46 (95 % confidence interval 1.01-2.13), P = 0.048]. The cumulative liver-related-symptoms-free rate of patients treated with bezafibrate and who had a normal ALT level was significantly higher than that of those treated with bezafibrate and who had an elevated ALT level (P < 0.001), and was comparable to that of those who received UDCA monotherapy.

CONCLUSION

These results suggested that normalization of ALT levels with additional bezafibrate treatment significantly decreased the rate of occurrence of liver-related symptoms in asymptomatic PBC patients with suboptimal response to UDCA.

Progress in treatment of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic autoimmune cholestatic liver disease characterized by cholestasis, and it often eventually develops into cirrhosis, portal hypertension and liver failure. Asymptomatic patients typically are diagnosed by the elevation of alkaline phosphatase (ALP) and the presence of anti-mitochondrial antibody (AMA) titers of 1:40 or greater. Ursodeoxycholic acid (UDCA) is the only Food and Drug Administration approved treatment for PBC, but it is not universally effective. In patients with UDCA-refractory PBC, additional therapies should be considered, including budesonide, fibrates, obeticholic acid, immunosuppressants and liver transplantation.