Investigational farnesoid X receptor agonists for the treatment of primary biliary cholangitis

INTRODUCTION

Up to 40% of Primary biliary cholangitis (PBC) patients have a suboptimal response to Ursodeoxycholic acid (UDCA). Close to half of such patients show a remarkable improvement when additionally treated with Obeticholic acid (OCA) but have a dose-dependent increase of pruritus. This relative success of OCA, a first-in-class Farnesoid receptor (FXR) agonist, has positioned FXR as an attractive target for drug development. Novel candidates have since emerged, providing hope for this subgroup of patients who lack effective and safe treatments.

AREAS COVERED

We discussed the role of bile acids in PBC pathogenesis and how the FXR agonists provide therapeutic value by affecting bile acid synthesis and transport. Novel FXR agonists undergoing pre-clinical and clinical trials for PBC were enlisted via literature search by including the terms 'FXR agonists,' 'FXR PBC,' 'PBC clinical trials' on PubMed, MEDLINE via Ovid, and Clinicaltrials.gov.

EXPERT OPINION

Novel FXR agonists currently under investigation for PBC improve the disease surrogate markers in early trials. However, as with OCA, pruritus remains a concern with the newer drugs despite targeted chemical modifications to increase FXR specificity. Directing future resources toward studying the molecular mechanisms behind pruritus may lead to better drug design and efficacious yet safer drugs.

Safety, pharmacokinetics and pharmacodynamics of obeticholic acid in subjects with fibrosis or cirrhosis from NASH

BACKGROUND & AIMS

Fibrosis stage is a strong predictor of nonalcoholic steatohepatitis (NASH) outcomes. Two blinded studies evaluated the pharmacokinetics, pharmacodynamics and safety of obeticholic acid (OCA) in subjects with staged NASH fibrosis or cirrhosis.

METHODS

Study 747-117 randomized 51 subjects with NASH (fibrosis stages F1-F4) to daily placebo, OCA 10 or OCA 25 mg (1:2:2) for 85 days. Study 747-118 randomized 24 subjects with NASH cirrhosis (F4; Child-Pugh [CP]-A) and normal liver control subjects matched for similar body weight to daily OCA 10 or OCA 25 mg (1:1) for 28 days. Individual and combined study data were analysed.

RESULTS

No severe or serious adverse events (AEs) or AEs leading to discontinuation or death occurred. Pruritus was the most frequent AE. Plasma OCA exposure (dose-normalized area under the curve) increased with fibrosis stage but was a relatively poor predictor of hepatic OCA exposure (primary site of action), which remained constant across fibrosis stages F1-F3 and increased 1.8-fold compared with F1 in subjects with cirrhosis due to NASH. Both cohorts showed robust changes in farnesoid X receptor activation markers with OCA treatment and marked decreases in alanine transaminase, aspartate transaminase and gamma-glutamyltransferase.

CONCLUSIONS

Despite higher drug exposures in subjects with NASH cirrhosis, short-term daily treatment with OCA 10 or 25 mg was generally safe and well tolerated in subjects with NASH fibrosis or NASH CP-A cirrhosis. Both cohorts experienced improvements in nonhistologic pharmacodynamic markers consistent with previously conducted OCA phase 2 and phase 3 studies in NASH fibrosis.

Inhibition of ACOX1 enhances the therapeutic efficacy of obeticholic acid in treating non-alcoholic fatty liver disease and mitigates its lipotoxicity

Background and aims

High-dose Obeticholic acid exhibits promise for non-alcoholic fatty liver disease (NAFLD) treatment but can induce lipotoxicity. Our study sought to understand this mechanism and propose a solution.

Approach and Results

In a non-alcoholic fatty liver disease (NAFLD) model induced by a high-fat diet in FXR-/- mice, we pinpointed that FXR regulated the expression of ACOX1 through RNA-Seq analysis. In the livers of FXR-/- mice, both ACOX1 mRNA and protein expression notably decreased. In both HL-7702 and HEP-G2 cells, the silencing of FXR through shRNA plasmids decreased ACOX1 expression, while FXR activation with GW4064 increased it. These effects were reversible with the ACOX1-specific inhibitor, 10,12-Tricosadiynoic acid. In the NAFLD model of FXR-/- mice, The activation of ACOX1 is correlated with elevated serum LDL, triglycerides, and aggravated hepatic steatosis. However, the combination of 10,12-Tricosadiynoic acid with low-dose obeticholic acid effectively treated hepatic steatosis, reducing LDL levels in the NAFLD model of wild-type mice. This combination therapy demonstrated efficacy comparable to high-dose obeticholic acid alone. Notably, the combined drug regimen treats hepatic steatosis by inhibiting the IL-1β and α-SMA pathways in NAFLD.

Conclusion

Combining ACOX1-specific inhibitors with low-dose obeticholic acid effectively treats high-fat diet-induced hepatic steatosis and reduces serum LDL. This approach enhances the therapeutic effects of obeticholic acid and mitigates its lipotoxicity by inhibiting the IL-1β and α-SMA pathways.

Emerging drugs for the treatment of hepatic fibrosis on nonalcoholic steatohepatitis

INTRODUCTION

Approved drug therapies for nonalcoholic steatohepatitis (NASH) are lacking, for which various agents are currently being tested in clinical trials. Effective drugs for liver fibrosis, the factor most associated with prognosis in NASH, are important.

AREAS COVERED

This study reviewed the treatment of NASH with a focus on the effects of existing drugs and new drugs on liver fibrosis.

EXPERT OPINION

Considering the complex pathophysiology of fibrosis in NASH, drug therapy may target multiple pathways. The method of assessing fibrosis is important when considering treatment for liver fibrosis in NASH. The Food and Drug Administration considers an important fibrosis endpoint to be histological improvement in at least one fibrosis stage while preventing worsening of fatty hepatitis. To obtain approval as a drug for NASH, efficacy needs to be demonstrated on endpoints such as liver-related events and myocardial infarction. Among the current therapeutic agents for NASH, thiazolidinedione, sodium-glucose co-transporter 2, and selective peroxisome proliferator-activated receptors α modulator have been reported to be effective against fibrosis, although further evidence is required. The effects of pan-peroxisome proliferator-activated receptors, obeticholic acid, and fibroblast growth factor-21 analogs on liver fibrosis in the development stage therapeutics for NASH are of particular interest.

Hepatic-Accumulated Obeticholic Acid and Atorvastatin Self-Assembled Nanocrystals Potentiate Ameliorative Effects in Treatment of Metabolic-Associated Fatty Liver Disease

Exploration of medicines for efficient and safe management of metabolic-associated fatty liver disease (MAFLD) remains a challenge. Obeticholic acid (OCA), a selective farnesoid X receptor agonist, has been reported to ameliorate injury and inflammation in various liver diseases. However, its clinical application is mainly limited by poor solubility, low bioavailability, and potential side effects. Herein a hepatic-targeted nanodrugs composed of OCA and cholesterol-lowering atorvastatin (AHT) with an ideal active pharmaceutical ingredient (API) content for orally combined treatment of MAFLD is created. Such carrier-free nanocrystals (OCAHTs) are self-assembled, not only improving the stability in gastroenteric environments but also achieving hepatic accumulation through the bile acid transporter-mediated enterohepatic recycling process. Orally administrated OCAHT outperforms the simple combination of OCA and AHT in ameliorating of liver damage and inflammation in both acetaminophen-challenged mice and high-fat diet-induced MAFLD mice with less systematic toxicity. Importantly, OCAHT exerts profoundly reverse effects on MAFLD-associated molecular pathways, including impairing lipid metabolism, reducing inflammation, and enhancing the antioxidation response. This work not only provides a facile bile acid transporter-based strategy for hepatic-targeting drug delivery but also presents an efficient and safe full-API nanocrystal with which to facilitate the practical translation of nanomedicines against MAFLD.

The effect and safety of obeticholic acid for patients with nonalcoholic steatohepatitis: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NASH) is one of the primary causes of chronic liver disease worldwide. Obeticholic acid (OCA), a potent farnesoid X nuclear receptor activator, has shown promise for treating NASH-related fibrosis due to its anti-fibrotic effects. This study aimed to examine the efficacy of OCA for patients with NASH as well as to investigate its impact on dyslipidemia.

METHOD

A search of databases including PubMed, Embase, and Cochrane Library from January 1, 2010, to November 1, 2022, was conducted to identify systematic reviews of randomized controlled trials involving NASH patients. Inclusion criteria comprised randomized controlled trials that specifically addressed NASH as diagnosed through magnetic resonance imaging, computed tomography, or histology. The results were then categorized, with consideration given to both biochemical and histological outcomes.

RESULT

Five NASH studies were ultimately selected for further analysis. In terms of biochemical indicators, patients receiving OCA treatment showed improvements in alanine transaminase (mean difference: -19.48, 95% confidence interval [CI]: -24.39 to 14.58; P < .05) and aspartate aminotransferase (mean difference: -9.22, 95% CI: -12.70 to 5.74; P < .05). As for histological improvement, OCA treatment reduced fibrosis (odds ratio [OR]: 1.95, 95% CI: 1.47-2.59; P = .001) and steatosis (OR: 1.95, 95% CI: 1.47-2.59; P = .001). No significant differences were observed regarding adverse events (1.44, 95% CI: 0.57-3.62; P > .001). Regarding dyslipidemia, mean differences between total cholesterol and low-density lipoprotein were found to be high (0.33, 95% CI: 0.01-0.64, P < .05; 0.39, 95% CI: 0.04-0.73, P < .05). In the case of pruritus, OCA achieved a high OR (3.22, 95% CI: 2.22-4.74) compared with placebo.

CONCLUSION

OCA also reduced several liver test markers compared to placebo, including the biochemical indicators alanine transaminase, aspartate aminotransferase, alkaline phosphatase, and γ-glutamyl transpeptidase, and improved hepatocellular ballooning, fibrosis, steatosis, and lobular inflammation. Although the incidence of adverse events did not significantly differ between OCA and placebo groups among NASH patients, OCA treatment was found to elevate total cholesterol and low-density lipoprotein levels, and the reported severity of pruritus increased with higher doses of OCA.

Healthy diet intervention reverses the progression of NASH through gut microbiota modulation

IMPORTANCE

The link between gut microbiota and diet is crucial in the development of non-alcoholic steatohepatitis (NASH). This study underscores the essential role of a healthy diet in preventing and treating NASH by reversing obesity, lipidemia, and gut microbiota dysbiosis. Moreover, the supplementation of functional food or drug to the diet can provide additional advantages by inhibiting hepatic inflammation through the modulation of the hepatic inflammasome signaling pathway and partially mediating the gut microbiota and lipopolysaccharide signaling pathway. This study highlights the importance of adopting healthy dietary habits in treating NASH and proposes that supplementing with ginger essential oil or obeticholic acid may offer additional benefits. Nonetheless, further clinical studies are necessary to validate these findings.

A Short Review on Obeticholic Acid: An Effective Modulator of Farnesoid X Receptor

Farnesoid X receptor (FXR) was identified as an orphan nuclear receptor resembling the steroid receptor in the late '90s. Activation of FXR is a crucial step in many physiological functions of the liver. A vital role of FXR is impacting the amount of bile acids in the hepatocytes, which it performs by reducing bile acid synthesis, stimulating the bile salt export pump, and inhibiting its enterohepatic circulation, thus protecting the hepatocytes against the toxic accumulation of bile acids. Furthermore, FXR mediates bile acid biotransformation in the intestine, liver regeneration, glucose hemostasis, and lipid metabolism. In this review, we first discuss the mechanisms of the disparate pleiotropic actions of FXR agonists. We then delve into the pharmacokinetics of Obeticholic acid (OCA), the first-in-class selective, potent FXR agonist. We additionally discuss the clinical journey of OCA in humans, its current evidence in various human diseases, and its plausible roles in the future.

Liver biopsy for assessment of suspected drug-induced liver injury in metabolic dysfunction-associated steatohepatitis clinical trials: Expert consensus from the Liver Forum

BACKGROUND

Causality assessment of suspected drug-induced liver injury (DILI) during metabolic dysfunction-associated steatohepatitis (MASH) clinical trials can be challenging, and liver biopsies are not routinely performed as part of this evaluation. While the field is moving away from liver biopsy as a diagnostic and prognostic tool, information not identified by non-invasive testing may be provided on histology.

AIM

To address the appropriate utilisation of liver biopsy as part of DILI causality assessment in this setting.

METHODS

From 2020 to 2022, the Liver Forum convened a series of webinars on issues pertaining to liver biopsy during MASH trials. The Histology Working Group was formed to generate a series of consensus documents addressing these challenges. This manuscript focuses on liver biopsy as part of DILI causality assessment.

RESULTS

Expert opinion, guidance and recommendations on the role of liver biopsy as part of causality assessment of suspected DILI occurring during clinical trials for a drug(s) being developed for MASH are provided. Lessons learned from prior MASH programs are reviewed and gaps identified.

CONCLUSIONS

Although there are no pathognomonic features, histologic evaluation of suspected DILI during MASH clinical trials may alter patient management, define the pattern and severity of injury, detect findings that favour a diagnosis of DILI versus MASH progression, identify prognostic features, characterise the clinicopathological phenotype of DILI, and/or define lesions that influence decisions about trial discontinuation and further development of the drug.

Bile acid metabolomics identifies chenodeoxycholic acid as a therapeutic agent for pancreatic necrosis

Bile acids are altered and associated with prognosis in patients with acute pancreatitis (AP). Here, we conduct targeted metabolomic analyses to detect bile acids changes in patients during the acute (n = 326) and the recovery (n = 133) phases of AP, as well as in healthy controls (n = 60). Chenodeoxycholic acid (CDCA) decreases in the acute phase, increases in the recovery phase, and is associated with pancreatic necrosis. CDCA and its derivative obeticholic acid exhibit a protective effect against acinar cell injury in vitro and pancreatic necrosis in murine models, and RNA sequencing reveals that the oxidative phosphorylation pathway is mainly involved. Moreover, we find that overexpression of farnesoid X receptor (FXR, CDCA receptor) inhibits pancreatic necrosis, and interfering expression of FXR exhibits an opposite phenotype in mice. Our results possibly suggest that targeting CDCA is a potential strategy for the treatment of acinar cell necrosis in AP, but further verification is needed.

Results from a new efficacy and safety analysis of the REGENERATE trial of obeticholic acid for treatment of pre-cirrhotic fibrosis due to non-alcoholic steatohepatitis

BACKGROUND & AIMS

Obeticholic acid (OCA) is a first-in-class farnesoid X receptor agonist and antifibrotic agent in development for the treatment of pre-cirrhotic liver fibrosis due to non-alcoholic steatohepatitis (NASH). We aimed to validate the original 18-month liver biopsy analysis from the phase III REGENERATE trial of OCA for the treatment of NASH with a consensus panel analysis, provide additional histology data in a larger population, and evaluate safety from >8,000 total patient-years' exposure with nearly 1,000 participants receiving study drug for >4 years.

METHODS

Digitized whole-slide images were evaluated independently by panels of three pathologists using the NASH Clinical Research Network scoring system. Primary endpoints were (1) ≥1 stage improvement in fibrosis with no worsening of NASH or (2) NASH resolution with no worsening of fibrosis. Safety was assessed by laboratory values and adverse events.

RESULTS

Prespecified efficacy analyses included 931 participants. The proportion of participants achieving a ≥1 stage improvement in fibrosis with no worsening of NASH was 22.4% for OCA 25 mg vs. 9.6% for placebo (p <0.0001). More participants receiving OCA 25 mg vs. placebo achieved NASH resolution with no worsening of fibrosis (6.5% vs. 3.5%, respectively; p = 0.093). Histology data in a larger population of 1,607 participants supported these results. Safety data included 2,477 participants. The incidence of treatment-emergent adverse events (TEAEs), serious TEAEs, and deaths was not substantively different across treatment groups. Pruritus was the most common TEAE. Rates of adjudicated hepatic, renal, and cardiovascular events were low and similar across treatment groups.

CONCLUSIONS

These results confirm the antifibrotic effect of OCA 25 mg. OCA was generally well tolerated over long-term dosing. These data support a positive benefit:risk profile in patients with pre-cirrhotic liver fibrosis due to NASH.

IMPACT AND IMPLICATIONS

Patients with non-alcoholic steatohepatitis (NASH) often have liver scarring (fibrosis), which causes an increased risk of liver-related illness and death. Preventing progression of fibrosis to cirrhosis or reversing fibrosis are the main goals of drug development for NASH. In this clinical trial of obeticholic acid (OCA) in patients with NASH (REGENERATE), we reaffirmed our previous results demonstrating that OCA was superior to placebo in improving fibrosis using a more rigorous consensus panel analysis of liver biopsies taken at month 18. We also showed that OCA treatment resulted in dose-dependent reductions of serum liver biochemistries and liver stiffness measurements compared with placebo, even in participants in whom histologic fibrosis did not change at 18 months, providing evidence that the benefit of OCA extends beyond what is captured by the ordinal NASH CRN scoring system. OCA was well tolerated with a favorable safety profile supporting a positive benefit: risk profile in patients with pre-cirrhotic liver fibrosis due to NASH.

Obeticholic acid and ferrostatin-1 differentially ameliorate non-alcoholic steatohepatitis in AMLN diet-fed ob/ob mice

Introduction: Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are common chronic liver diseases with limited treatment options. Methods: Ob/ob mice (6 weeks old) were fed with the Control diet or amylin liver NASH (AMLN) diet for 24 weeks to establish the NASH, the AMLN diet-fed mice were treated with obeticholic acid (OCA), ferrostatin-1 (Fer-1) or their combination for 7 weeks. Finally, various clinical profiles were assessed. Results: Our results indicate that Fer-1 exerts better effects on improving body weight, blood glucose levels, transaminase levels and insulin resistance than OCA. OCA has a profound effect on ameliorating lipid accumulation. OCA and Fer-1 differentially inhibit the activation of hepatic Kupffer cells and HSCs. The combination of OCA and Fer-1 significantly reduces inflammation and protects mice against liver oxidative stress. OCA and Fer-1 differentially reshape the intestinal microbiota and affect the hepatic lipidome. Discussion: Our study compares the effects of OCA, Fer-1 and their combination on various clinical profiles in NASH. These data demonstrate that different drug combinations results in different improvements, and these discoveries provide a reference for the use of the OCA, Fer-1 and their combination in the clinical treatment of NAFLD/NASH.

Obeticholic Acid for Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a rare autoimmune cholestatic liver disease that may progress to fibrosis and/or cirrhosis. Treatment options are currently limited. The first-line therapy for this disease is the drug ursodeoxycholic acid (UDCA), which has been proven to normalize serum markers of liver dysfunction, halt histologic disease progression, and lead to a prolongation of transplant-free survival. However, 30–40% of patients unfortunately do not respond to this first-line therapy. Obeticholic acid (OCA) is the only registered agent for second-line treatment in UDCA-non responders. In this review, we focus on the pharmacological features of OCA, describing its mechanism of action of and its tolerability and efficacy in PBC patients. We also highlight current perspectives on future therapies for this condition.

Hepatocellular carcinoma: Novel understandings and therapeutic strategies based on bile acids (Review)

Bile acids (BAs) are the major components of bile and products of cholesterol metabolism. Cholesterol is catalyzed by a variety of enzymes in the liver to form primary BAs, which are excreted into the intestine with bile, and secondary BAs are formed under the modification of the gut microbiota. Most of the BAs return to the liver via the portal vein, completing the process of enterohepatic circulation. BAs have an important role in the development of hepatocellular carcinoma (HCC), which may participate in the progression of HCC by recognizing receptors such as farnesoid X receptor (FXR) and mediating multiple downstream pathways. Certain BAs, such as ursodeoxycholic acid and obeticholic acid, were indicated to be able to delay liver injury and HCC progression. In the present review, the structure and function of BAs were introduced and the metabolism of BAs and the process of enterohepatic circulation were outlined. Furthermore, the mechanisms by which BAs participate in the development of HCC were summarized and possible strategies for targeting BAs and key sites of their metabolic processes to treat HCC were suggested.

Cost-effectiveness of obeticholic acid for the treatment of non-alcoholic steatohepatitis: An early economic evaluation

BACKGROUND

Currently, there are no pharmacological options available for the treatment of non-alcoholic steatohepatitis (NASH). In the 18-month interim analysis of an ongoing randomized, placebo-controlled phase 3 trial (REGENERATE), early results demonstrated that obeticholic acid (OCA) 25 mg significantly improved fibrosis with no worsening of NASH among patients with NASH and fibrosis compared with placebo (PBO). This study aimed to assess the potential cost-effectiveness of OCA compared with PBO in NASH patients.

METHODS

A state-transition model was developed to perform a cost-utility analysis comparing two treatment strategies, PBO and OCA 25 mg, from a Canadian public payer perspective. The model time horizon was lifetime with annual cycle lengths. Cost and utility parameters were discounted at 1.5% annually. The efficacy data were obtained from the REGENERATE trial, and costs and utilities were derived from other published literature. Probabilistic and deterministic sensitivity analyses were performed to test the robustness of the model.

RESULTS

Treatment with OCA led to reductions of 3.58% in decompensated cirrhosis cases, 3.95% in hepatocellular carcinoma, 7.88% in liver transplant, and 6.01% in liver-related death. However, at an annual price of CAD $36,000, OCA failed to be cost-effective compared with PBO at an incremental cost-effectiveness ratio of $815,514 per quality-adjusted life year (QALY). An 88% reduction in drug price to an annual cost of $4,300 would make OCA cost-effective at a willingness-to-pay threshold of $50,000/QALY.

CONCLUSIONS

OCA failed to be cost-effective compared with PBO, despite demonstrating clinical benefits due to a high drug cost. A significant price reduction would be needed to make the drug cost-effective.

Farnesoid X Receptor as Target for Therapies to Treat Cholestasis-Induced Liver Injury

Recent studies on liver disease burden worldwide estimated that cirrhosis is the 11th most common cause of death globally, and there is a great need for new therapies to limit the progression of liver injuries in the early stages. Cholestasis is caused by accumulation of hydrophobic bile acids (BA) in the liver due to dysfunctional BA efflux or bile flow into the gall bladder. Therefore, strategies to increase detoxification of hydrophobic BA and downregulate genes involved in BA production are largely investigated. Farnesoid X receptor (FXR) has a central role in BA homeostasis and recent publications revealed that changes in autophagy due to BA-induced reactive oxygen species and increased anti-oxidant response via nuclear factor E2-related factor 2 (NRF2), result in dysregulation of FXR signaling. Several mechanistic studies have identified new dysfunctions of the cholestatic liver at cellular and molecular level, opening new venues for developing more performant therapies.

Obeticholic acid ameliorates obesity and hepatic steatosis by activating brown fat

Obeticholic acid (OCA) is exemplified as a potent drug for treating primary biliary cirrhosis and nonalcoholic fatty liver disease by inhibiting bile acid synthesis. However, it remains unclear whether the effect of OCA is mediated by the function of brown adipose tissue (BAT). In the present study, brown adipogenesis differentiation in vitro and db/db mouse model treated with OCA were used to assess the anti-obesity function by body weight tracking, O₂ consumption, food intake, physical activity, glucose tolerance tests. In addition, uncoupling protein 1 (Ucp1) protein expression in brown adipose tissue was measured by western blotting, morphometry of brown adipose tissue was analyzed by hematoxylin and eosin staining. Hepatic steatosis was detected by Oil-Red O staining and serological analysis was performed to assess the effect of OCA on hyperlipidemia. OCA treatment enhanced brown adipocyte cell differentiation and upregulated the expression of the BAT-specific gene Ucp1) in C3H10T1/2 cells in vitro. Consistent with these findings, OCA increased whole-body energy metabolism and glucose homeostasis by enhancing BAT activity in vivo, and ultimately decreased body weight gain in db/db mice. In addition, the results demonstrated that spontaneous hepatic steatosis in db/db mice was ameliorated following OCA treatment. In summary, OCA functioned as a BAT activator to help ameliorate obesity and maintain glucose homeostasis in db/db mice. The present results may provide a novel potential therapeutic approach to activate brown fat in patients with obesity and other metabolic disorders.

Co-administration of obeticholic acid and simvastatin protects against high-fat diet-induced non-alcoholic steatohepatitis in mice

Non-alcoholic steatohepatitis (NASH) has no approved therapy. The farnesoid X nuclear receptor (FXR) agonist obeticholic acid (OCA) has shown promise as a drug for NASH, but can adversely affect plasma lipid profiles. Therefore, the present study aimed to investigate the effects and underlying mechanisms of OCA in combination with simvastatin (SIM) in a high-fat diet (HFD)-induced model of NASH. C57BL/6J mice were fed with a HFD for 16 weeks to establish the NASH model. The mice were randomly divided into the following five groups: HFD, HFD + OCA, HFD + SIM, HFD + OCA + SIM and control. After 16 weeks, the mice were sacrificed under anesthesia. The ratios of liver weight to body weight (Lw/Bw) and of abdominal adipose tissue weight to body weight were calculated. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol, triglycerides and low-density lipoprotein were measured. Liver sections were stained with hematoxylin and eosin. The protein levels of FXR, small heterodimeric partner (SHP) and cytochrome P450 family 7 subfamily A member 1 (CYP7A1) in the liver were detected by western blotting, while the mRNA levels of FXR, SHP, CYP7A1, bile salt export pump, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), sterol regulatory element binding protein-1 (SREBP1) and fatty acid synthase (FASN) were examined by reverse transcription-quantitative polymerase chain reaction. The administration of OCA with or without SIM reduced the liver inflammation score compared with those of the HFD and HFD + SIM groups, with no significant difference between the HFD + OCA and HFD + OCA + SIM groups. The steatosis score followed similar trends to the inflammation score. In HFD-fed mice, OCA combined with SIM prevented body weight gain compared with that in HFD and HFD + OCA groups, and reduced the Lw/Bw ratio compared with that in the HFD and HFD + SIM groups. In addition to preventing HFD-induced increases of ALT and AST, the combination of OCA and SIM reduced the mRNA levels of IL-6, TNF-α, SREBP1 and FASN. On the basis of these results, it may be concluded that the strategy of combining OCA with SIM represents an effective pharmacotherapy for NASH.

The identification of farnesoid X receptor modulators as treatment options for nonalcoholic fatty liver disease

INTRODUCTION

The farnesoid-x-receptor (FXR) is a ubiquitously expressed nuclear receptor selectively activated by primary bile acids.

AREA COVERED

FXR is a validated pharmacological target. Herein, the authors review preclinical and clinical data supporting the development of FXR agonists in the treatment of nonalcoholic fatty liver disease.

EXPERT OPINION

Development of systemic FXR agonists to treat the metabolic liver disease has been proven challenging because the side effects associated with these agents including increased levels of cholesterol and LDL-c and reduced HDL-c raising concerns over their long-term cardiovascular safety. Additionally, pruritus has emerged as a common, although poorly explained, dose-related side effect with all FXR ligands, but is especially common with OCA. FXR agonists that are currently undergoing phase 2/3 trials are cilofexor, tropifexor, nidufexor and MET409. Some of these agents are currently being developed as combination therapies with other agents including cenicriviroc, a CCR2/CCR5 inhibitor, or firsocostat an acetyl CoA carboxylase inhibitor. Additional investigations are needed to evaluate the beneficial effects of combination of these agents with statins. It is expected that in the coming years, FXR agonists will be developed as a combination therapy to minimize side effects and increase likelihood of success by targeting different metabolic pathways.

Obeticholic Acid Inhibits Anxiety via Alleviating Gut Microbiota-Mediated Microglia Accumulation in the Brain of High-Fat High-Sugar Diet Mice

Anxiety is one of the complications of metabolic disorders (MDs). Obeticholic acid (OCA), the bile acids (BAs) derivative, is a promising agent for improving MDs in association with gut dysbiosis. Yet, its protective effect on MDs-driven anxiety remains unknown. Here, we assessed the serum biochemical parameters and behavioral performance by open field and Morris water maze tests in HFHS diet-induced MDs mice after OCA intervention for nine and 18 weeks. Moreover, antibiotics intervention for microbial depletion was conducted simultaneously. We found that OCA treatment inhibited the initiation and progression of anxiety in HFHS diet-MDs mice via a microbiota–BAs–brain axis: OCA decreased the neuroinflammatory microglia and IL-1β expression in the hippocampus, reversed intestinal barrier dysfunction and serum proinflammatory LPS to a normal level, modified the microbial community, including the known anxiety-related Rikenellaceae and Alistipes, and improved the microbial metabolites especially the increased BAs in feces and circulation. Moreover, the OCA-reversed bile acid taurocholate linked disordered serum lipid metabolites and indole derivatives to anxiety as assessed by network analysis. Additionally, microbial depletion with antibiotics also improved the anxiety, microgliosis and BAs enrichment in the experimental MDs mice. Together, these findings provide microbiota–BAs–brain axis as a novel therapeutic target for MDs-associated neuropsychiatric disorders.

Emerging therapies for the treatment of nonalcoholic steatohepatitis: A systematic review

To describe the mechanism, efficacy, and safety of novel agents that have reached phase 3 clinical trials for the treatment of biopsy-proven nonalcoholic steatohepatitis (NASH). A literature search was conducted using the PRISMA guidelines of MEDLINE databases (1990 to October 2020) with the following MeSH terms: NASH, nonalcoholic liver disease, fatty liver, liver diseases, steatohepatitis, liver fibrosis; combined with obeticholic acid, FXR agonist, cenicriviroc, CCR5 receptor antagonist, elafibranor, PPAR, selonsertib, ASK-1 inhibitor, resmetirom, THR-β receptor, arachidyl amido cholanoic acid (Aramchol™), and SCD-1 modulator. Results were verified via clinicaltrials.gov, Google Scholar, and Google. Articles were included if the medications of interest had ongoing or completed phase 3 trials in biopsy-proven NASH with outcomes directly related to NASH resolution. Eleven studies were identified involving obeticholic acid (OCA), elafibranor, cenicriviroc, Aramchol, and resmetirom. Two agents have reported data from phase 3 trials: OCA and elafibranor. OCA demonstrated safety and efficacy in NASH with a primary end point of improvement or NASH resolution; a new drug approval has been submitted. Elafibranor failed to show efficacy in NASH in the preliminary report from the RESOLVE-IT trial; however, the study is being extended to reassess outcomes. The remaining agents demonstrated positive results in phase 2b studies and have initiated phase 3 trials. With projections for increased prevalence of patients with NASH and the current lack of treatment options, novel agents with targeted mechanisms could potentially change the treatment landscape. The manufacturer of OCA is first to submit a new drug application for the treatment of NASH. These novel agents may fill a pharmacotherapy gap in patients with NASH and possibly prevent progression to advanced liver disease.

A novel LC-MS/MS method for simultaneous estimation of obeticholic acid, glyco-obeticholic acid, tauro-obeticholic acid in human plasma and its application to a pharmacokinetic study

A rapid, robust, simple, selective, and sensitive liquid chromatography-tandem mass spectrometry method was developed for the simultaneous estimation of obeticholic acid and its two pharmacologically active metabolites, glyco-obeticholic acid, and tauro-obeticholic acid in human plasma. The analytes and their heavy stable isotope-labeled internal standards were extracted from 250 μL human plasma by a solid-phase extraction technique. The method linearity was established over a concentration range of 0.410 to 120.466 ng/mL for obeticholic acid, 0.414 to 121.708 ng/mL for glyco-obeticholic acid, and 0.255 to 75.101 ng/mL for tauro-obeticholic acid. The method was fully validated as per current guidelines on bioanalytical method validation of "United States of Food and Drug Administration" and "European Medicines Agency." The method was successfully applied to study the pharmacokinetics of obeticholic acid, glyco-obeticholic acid, and tauro-obeticholic acid following oral administration of obeticholic acid tablets to healthy male volunteers. All the measured concentrations were within calibration curve ranges.

Bioequivalence and Pharmacokinetic Profiles of Generic and Branded Obeticholic Acid in Healthy Chinese Subjects Under Fasting and Fed Conditions

Objectives

This study was conducted to evaluate the bioequivalence (BE) of a generic form of obeticholic acid (OCA) and Ocaliva^TM under fasting and fed conditions and to determine the effects of food on the pharmacokinetic (PK) profiles of OCA in healthy Chinese subjects.

Methods

A randomized, single-dose, three-sequence, three-period, partial replicated crossover study was conducted with a 21-day washout interval between periods under fasting (n=48) and fed (n=48) conditions. Blood samples for OCA and its metabolites Glyco-OCA and Tauro-OCA were collected up to 168 hours after administration in each period. PK parameters were calculated using the non-compartmental method. Geometric mean ratios for PK parameters of the test to reference drug under fasting and fed conditions and their 90% confidence intervals were estimated. Safety evaluations were carried out all through the study.

Results

A total of 91 subjects completed the study with 45 in a fasted state and 46 receiving a high-fat diet. There were no serious or unexpected drug-related adverse events occurring during the study. There was no significant difference in the main PK parameters of the two preparations, irrespective of the fasting or fed conditions. Under fasting and fed conditions, the S_WR of lnC_max, lnAUC_0-t and lnAUC_0-∞ were 0.445, 0.370, 0.448, 0.340, 0.168, and 0.180, respectively. Thus, the average BE or the reference-scaled average BE was used to verify that the two preparations were bioequivalent under fasting and fed conditions. Compared with the fasting state, the AUC_0-t of the test drug, the AUC_0-t, and AUC_0-∞ of the reference drug were higher in the fed state.

Conclusion

The test drug and the reference drug were BE and well tolerated in Chinese healthy subjects under both fasting and fed conditions. Food-intake may cause a significant difference in the main PK parameters of the two preparations.

Comparison of the Pharmacokinetics of Generic Versus Branded Obeticholic Acid in a Chinese Population: Effects of Food and Sex

The present study assessed the pharmacokinetics and bioequivalence of a single 10-mg dose of a generic and the branded formulation (Ocaliva) of obeticholic acid (OCA) in healthy Chinese subjects under fasting and fed conditions. The possible effects of food and sex on the pharmacokinetics of OCA and its 2 active metabolites (glyco-OCA and tauro-OCA) were evaluated. Plasma concentrations of OCA and its 2 active metabolites were measured by liquid chromatography-tandem mass spectrometry. The 90%CIs of the ratios of the test and reference formulations for C_max , AUC_0-t , and AUC_0-∞ of OCA, glyco-OCA, and tauro-OCA were contained entirely within the 80% to 125% range required for bioequivalence under fasting and fed conditions. Plasma exposure of OCA was 30% to 36% higher under fed compared with fasting conditions. Plasma exposure of OCA, glyco-OCA, and tauro-OCA was 39% to 66%, 22% to 58%, and 37% to 84% higher, respectively, in women compared with men under fasting and fed conditions. In conclusion, OCA was well tolerated in healthy Chinese subjects under fasting and fed conditions. The single 10-mg dose of a generic OCA formulation was bioequivalent to Ocaliva. Food and sex impacted the pharmacokinetics of OCA and/or its 2 active metabolites. Further studies are required to determine if these effects are clinically relevant.

Experimental Pharmacological Agents for the Treatment of Primary Biliary Cholangitis

The standard therapy for primary biliary cholangitis (PBC) is ursodeoxycholic acid (UDCA) which has shown to improve hepatic biochemistry, delay histological progression and improve transplant-free survival. Approximately 30-40% of patients do not respond or are intolerant to UDCA. Obeticholic acid, a farnesoid X receptor (FXR) agonist is the only agent approved by the Food and Drug Administration for patients who do not respond to UDCA. Recently, combination therapy with UDCA and bezafibrate has been shown to improve biochemistry and both GLOBE and UK-PBC score in patients with an inadequate response to UDCA. More recently, new pharmacological agents have been included in Phase 2 and Phase 3 trials: PPAR agonists, non-bile acid FXR agonists, anti-NOX agents, immunomodulators and mesenchymal stem cells transplantation. This review gives an overview on the current experimental pharmacological agents employed in the treatment of PBC.

Farnesoid X receptor activation induces antitumour activity in colorectal cancer by suppressing JAK2/STAT3 signalling via transactivation of SOCS3 gene

Farnesoid X receptor (FXR, encoded by NR1H4), a bile acid‐activated nuclear receptor, is widely implicated in human tumorigenesis. The FXR agonist obeticholic acid (OCA) has preliminarily displayed tumour suppressor potential. However, the anticancer effects of this agent on colorectal cancer (CRC) remain unclear. In this study, the treatment of colon cancer cells with OCA inhibited cell proliferation and invasion in vitro, retarded tumour growth in vivo and prevented the G₀/G₁ to S phase transition. Moreover, the expression of active caspase‐3, p21 and E‐cadherin was up‐regulated and the expression of cyclin D1, c‐Myc, vimentin, N‐cadherin and MMP9 was down‐regulated in OCA‐treated colon cancer cells. Mechanistic studies indicated that OCA treatment suppressed the activity of JAK2/STAT3 pathway by up‐regulating SOCS3 expression. Colivelin, an agonist of JAK2/STAT3 pathway, antagonized the tumour‐suppressive effect of OCA on colon cancer cells. Dual‐luciferase reporter and quantitative chromatin immunoprecipitation (qChIP) assays further confirmed that OCA promoted SOCS3 transcription by enhancing the binding of FXR to the FXRE/IR9 of the SOCS3 promoter. In conclusion, our study demonstrates that targeting FXR and improving its function might be a promising strategy for CRC treatment.

Primary biliary cholangitis management: controversies, perspectives and daily practice implications from an expert panel

Primary biliary cholangitis (PBC) is a rare progressive immune-mediated liver disease that, if not adequately treated, may culminate in end-stage disease and need for transplantation. According to current guidelines, PBC is diagnosed in the presence of antimitochondrial antibodies (AMA) or specific antinuclear antibodies, and of a cholestatic biochemical profile, while biopsy is recommended only in selected cases. All patients receive ursodeoxycholic acid (UDCA) in first line; the only registered second-line therapy is obeticholic acid (OCA) for UDCA-inadequate responders. Despite the recent advances in understanding PBC pathogenesis and developing new treatments, many grey areas remain. Six Italian experts selected the following topics as the most urgent to address in PBC management: diagnosis and natural history of PBC: as a portion of the subjects with isolated AMA, normal alkaline phosphatase (ALP) levels and no symptoms of liver disease could have PBC by histology, defining how to manage and follow this population is crucial; role of liver biopsy: recent evidence suggests that biopsy may provide relevant information for risk stratification and prediction of UDCA response, possibly facilitating personalized approaches; risk stratification: the tools for risk stratification are well established, but some issues (eg bile acid dosage in routine practice) remain controversial; and therapy: those in more advanced stages of development are nuclear receptor modulators and fibrates, but more data are needed to plan personalized strategies. In this manuscript, for each topic, current evidence, controversies and future perspectives are summarized with the possible implications for clinical practice.

Combination therapy of obeticholic acid and ursodeoxycholic acid in patients with primary biliary cholangitis who respond incompletely to ursodeoxycholic acid: a systematic review

BACKGROUND

Although the efficacy of ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) for primary biliary cholangitis (PBC) has been suggested by small trials, a meta-analysis to summarize the evidence has not yet been carried out. The aim of this study was to evaluate the clinical outcomes of the combination therapy of UDCA and OCA compared with UDCA monotherapy in patients with PBC.

METHODS AND MATERIALS

We searched the PubMed, EMBASE, the web of science, and the Cochrane Library databases for English-language studies published before September 2018. Studies were included if they were randomized controlled trials (RCTs) and reported relative risk (RR) estimates with 95% confidence intervals (CIs) or related data for the clinical outcomes of different therapies in patients with PBC.

RESULTS

Of the 1169 titles identified, two studies meeting the inclusion criteria were included in the meta-analysis. Approximately 222 patients with PBC were included in this analysis. The results of this study indicated that combination therapy was significantly superior to monotherapy in reducing serum alanine transaminase (mean difference: -15.63 IU/L; 95% CI, -21.59 to -9.68), aspartate transaminase (mean difference: -6.63 IU/L; 95% CI, -11.03 to -2.24), gamma-glutamyl transpeptidase (mean difference: -131.30 IU/L; 95% CI, -177.52 to -85.08), and C-reactive protein (mean difference = -1.17 mg/L; 95% CI, -2.19 to -0.14), but NS in improving primary endpoints of alkaline phosphatase level with 15.0% reduction from baseline, and equal or higher than the upper limit of normal serum total bilirubin (RR = 2.75; 95% CI, 0.43-17.68), conjugated bilirubin (mean difference = -0.06 mg/dL; 95% CI, -0.28 to 0.15), IgM (mean difference = -41.18 mg/dL; 95% CI, -244.45 to 162.09), and adverse events (P > 0.05).

CONCLUSION

This meta-analysis demonstrated that combination therapy with UDCA and OCA provided satisfactory clinical outcomes, which may be a promising alternative for patients with PBC who had an inadequate response to UDCA therapy. Therefore, high-quality RCTs on the safety and efficacy of the combination therapy of UDCA and OCA compared with UDCA monotherapy in patients with PBC should be performed in the future.

Diagnosis and treatment of primary biliary cholangitis

Primary biliary cholangitis is a cholestatic, chronic autoimmune liver disease with a wide individual variation in disease progression. The diagnosis is predominantly based on chronic elevation of alkaline phosphatase and the presence of anti-mitochondrial antibodies or other specific antinuclear antibodies (i.e. anti-gp210 and anti-sp100). Even in early-stage disease, health-related quality of life can be severely impaired by symptoms such as pruritus, fatigue, and sicca syndrome and metabolic bone disease should be assessed and treated. The prognosis of the disease is, however, largely determined by the development of cirrhosis and its complications. Ursodeoxycholic acid is associated with an improved prognosis and should be initiated and continued in all patients. Clinical outcome is related to the biochemical response to ursodeoxycholic acid, but the prognosis of those with an incomplete response is still better than those who remain untreated. Obeticholic acid was recently approved as second-line treatment and bezafibrate may serve as an adequate off-label alternative, particularly in patients with pruritus. Preliminary data suggest an additive effect of triple therapy with ursodeoxycholic acid, obeticholic acid, and bezafibrate, whereas other promising drugs are being evaluated in clinical trials.

Bile acid modulators for the treatment of nonalcoholic steatohepatitis (NASH)

INTRODUCTION

Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease (NAFLD) for which therapy is suboptimal. The farnesoid-X-receptor (FXR) and the G protein bile acid receptor (GPBAR)1 are two bile acid-activated receptors that exert regulatory effects on lipid, glucose, energy, and immune homeostasis. GPBAR1 and FXR ligands have shown efficacy in reversing steatohepatitis and fibrosis in preclinical models of NASH.

AREA COVERED

This article evaluates the efficacy and pitfalls of GPBAR1 and FXR-based therapies in the treatment of NASH. While there are no GPBAR1 agonist in clinical development, several FXR ligands have completed phase 2 and phase 3 trials in NASH. EDP305, tropifexor, cilofexor, nidufexor, TERN.101, Px-104, EYP001, MET409. Individual FXR agonists have shown variable efficacy in reversing liver steatohepatitis and fibrosis. Class-related, dose-dependent side effects: pruritus, increased plasma levels of cholesterol and LDLc, and reduction of HDL have been reported.

EXPERT OPINION

Efficacy of FXR agonists as stand-alone therapy is limited by dose-related side effects. Efficacy of combining an FXR agonist with statins, CCR2, and ACC inhibitors is currently investigated. Identification of patient subsets would allow development of patients tailored therapy using a combination of drugs acting on different molecular mechanisms.

Update on Emerging Treatment Options for Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a rare autoimmune cholestatic liver disease that may progress to fibrosis or cirrhosis. Treatment options are currently limited. Ursodeoxycholic acid (UDCA) remains first-line therapy and has been proven to normalize serum biochemistries, halt histologic disease progression, and lead to patient survival comparable to the general population. Obeticholic acid (OCA) was recently approved as adjunct therapy in PBC patients with inadequate response or intolerance to UDCA. However, OCA has been associated with worsening pruritus in clinical studies which may limit its use in this patient population. Several studies are currently underway to address the lack of treatment options for PBC. Of these, fibrates, which have been used in Japan for over a decade, have produced promising results. Furthermore, as currently approved therapies for PBC do not address the potentially debilitating clinical symptoms of PBC such as pruritus and fatigue, supplemental therapy is often required for symptom control.

Primary Biliary Cholangitis and Bile Acid Farnesoid X Receptor Agonists

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease characterized by the progressive destruction of the intrahepatic bile ducts. Currently, the first line drug for PBC is ursodeoxycholic acid (UDCA) characterized by anti-apoptotic, anti-inflammatory and protective actions on cholangiocytes. Despite its recognized therapeutic action, 30–40% of PBC patients only partially benefit from UDCA therapy. This has led to the identification of the role of the farnesoid x receptor (FXR) in cholestatic liver diseases and, consequently, to the development of obeticholic acid (OCA), a steroid FXR agonist that has been recently approved for the treatment of PBC. OCA though is not effective in all patients and can cause itch, which eventually induces treatment drop out. Therefore, the search for new therapeutic strategies for PBC has begun. This review, in addition to summarizing the current treatments for PBC, provides overview of the chemical characteristics of new steroid FXR agonist candidates that could represent a future perspective for the treatment of PBC.

Obeticholic acid for the treatment of nonalcoholic steatohepatitis

INTRODUCTION

NAFLD has grown to become the most prevalent liver disease in the world, with a quarter of the general population estimated to have the disease. NASH, characterized as NAFLD with inflammation, is associated with worsening fibrosis along with increased incidence of HCC. Despite high prevalence of this disease, no pharmacologic treatments approved by regulatory agencies are available.

AREAS COVERED

This review briefly discusses present understanding of NASH pathology and currently available treatments. We also discuss data on the role of OCA as an FXR agonist in modulating disease in NASH. A comprehensive literature search of review articles, original research articles, and prospective clinical trials from 1998 to the present was performed.

EXPERT OPINION

Based on 18-month interim findings of the REGENERATE trial, OCA likely improves fibrosis in NASH and therefore may have a beneficial effect in delaying or even preventing cirrhosis. The side effect of an atherogenic lipoprotein profile may adversely affect long-term outcomes, though studies have shown that co-administration of statins is able to mitigate this effect. OCA is likely to become an option for treatment, but the specific context within which it may be prescribed still needs to be clarified.

Corrigendum: Progression and Regression of Hepatic Lesions in a Mouse Model of NASH Induced by Dietary Intervention and Its Implications in Pharmacotherapy

[This corrects the article DOI: 10.3389/fphar.2018.00410.].

FXR activation promotes intestinal cholesterol excretion and attenuates hyperlipidemia in SR-B1-deficient mice fed a high-fat and high-cholesterol diet

Obeticholic acid (OCA) activates the farnesoid X receptor (FXR) to lower circulating total cholesterol (TC) and high density lipoprotein-cholesterol (HDL-C) concentrations and to stimulate fecal cholesterol excretion in mice by increasing hepatic SR-B1 expression. Here we show that hepatic SR-B1 depletion by an adenovirus expressing Sr-b1 shRNA (Ad-shSR-B1) attenuated these beneficial effects of OCA in mice on a chow diet. The mRNA levels of ABC cholesterol transporter genes (Abca1, Abcg1, Abcg5, and Abcg8) were unchanged in the liver of hepatic SR-B1-depleted mice regardless of OCA treatment; however, a modest increase in Abca1, Abcg5, and Abcg8 mRNA levels was observed in the ileum of vehicle-treated control mice and Abca1 and Abcg8 mRNA levels were increased more by OCA administration. OCA treatment of Sr-b1 knock out (KO) mice (Sr-b1-/-) fed a normal chow diet (NCD) displayed a similar lack of transhepatic cholesterol movement, as well as a modest increase in the levels of ileum cholesterol transporter expression. However, OCA treatment of Sr-b1 KO mice fed a cholesterol-enriched diet reduced circulating cholesterol and increased fecal cholesterol output to comparable degrees to that of wild-type (WT) mice, and these effects were accompanied by substantial elevations of mRNA levels of Abca1, Abcg1, Abcg5, and Abcg8 in the ileum of Sr-b1 KO mice. Our studies suggest that FXR activation stimulates intestinal cholesterol excretion and reduces diet-induced hyperlipidemia through increased expression of ileal cholesterol transporters when hepatic SR-B1-mediated cholesterol movement is absent.

miR-22 inhibition reduces hepatic steatosis via FGF21 and FGFR1 induction

Background & Aims

Metabolism supports cell proliferation and growth. Surprisingly, the tumor suppressor miR-22 is induced by metabolic stimulators like bile acids. Thus, this study examines whether miR-22 could be a metabolic silencer.

Methods

The relationship between miR-22 and the expression of fibroblast growth factor 21 (FGF21) and its receptor FGFR1 was studied in cells and fatty livers obtained from patients and mouse models. We evaluated the effect of an miR-22 inhibitor alone and in combination with obeticholic acid (OCA) for the treatment of steatosis.

Results

The levels of miR-22 were inversely correlated with those of FGF21, FGFR1, and PGC1α in human and mouse fatty livers, suggesting that hepatic miR-22 acts as a metabolic silencer. Indeed, miR-22 reduced FGFR1 by direct targeting and decreased FGF21 by reducing the recruitment of PPARα and PGC1α to their binding motifs. In contrast, an miR-22 inhibitor increases hepatic FGF21 and FGFR1, leading to AMPK and ERK1/2 activation, which was effective in treating alcoholic steatosis in mouse models. The farnesoid x receptor-agonist OCA induced FGF21 and FGFR1, as well as their inhibitor miR-22. An miR-22 inhibitor and OCA were effective in treating diet-induced steatosis, both alone and in combination. The combined treatment was the most effective at improving insulin sensitivity, releasing glucagon-like peptide 1, and reducing hepatic triglyceride in obese mice.

Conclusion

The simultaneous induction of miR-22, FGF21 and FGFR1 by metabolic stimulators may maintain FGF21 homeostasis and restrict ERK1/2 activation. Reducing miR-22 enhances hepatic FGF21 and activates AMPK, which could be a novel approach to treat steatosis and insulin resistance.

Lay summary

This study examines the metabolic role of a tumor suppressor, miR-22, that can be induced by metabolic stimulators such as bile acids. Our novel data revealed that the metabolic silencing effect of miR-22 occurs as a result of reductions in metabolic stimulators, which likely contribute to the development of fatty liver. Consistent with this finding, an miR-22 inhibitor effectively reversed both alcohol- and diet-induced fatty liver; miR-22 inhibition is a promising therapeutic option which could be used in combination with obeticholic acid.

Bile Acid Receptor Therapeutics Effects on Chronic Liver Diseases

In the past ten years, our understanding of the importance of bile acids has expanded from fat absorption and glucose/lipid/energy homeostasis into potential therapeutic targets for amelioration of chronic cholestatic liver diseases. The discovery of important bile acid signaling mechanisms, as well as their role in metabolism, has increased the interest in bile acid/bile acid receptor research development. Bile acid levels and speciation are dysregulated during liver injury/damage resulting in cytotoxicity, inflammation, and fibrosis. An increasing focus to target bile acid receptors, responsible for bile acid synthesis and circulation, such as Farnesoid X receptor and apical sodium-dependent bile acid transporter to reduce bile acid synthesis have resulted in clinical trials for treatment of previously untreatable chronic liver diseases such as non-alcoholic steatohepatitis and primary sclerosing cholangitis. This review focuses on current bile acid receptor mediators and their effects on parenchymal and non-parenchymal cells. Attention will also be brought to the gut/liver axis during chronic liver damage and its treatment with bile acid receptor modulators. Overall, these studies lend evidence to the importance of bile acids and their receptors on liver disease establishment and progression.

CONTROL: A randomized phase 2 study of obeticholic acid and atorvastatin on lipoproteins in nonalcoholic steatohepatitis patients

BACKGROUND & AIMS

Nonalcoholic steatohepatitis (NASH) is a chronic and severe form of nonalcoholic fatty liver disease that can progress to cirrhosis and hepatocellular carcinoma and is a risk factor for cardiovascular disease. Although NASH has no approved treatments, obeticholic acid (OCA), a synthetic bile acid and farnesoid X receptor (FXR) agonist, was shown to improve histological features of NASH and fibrosis. Considering that FXR activation influences plasma lipoprotein concentrations, the Combination OCA aNd sTatins for monitoRing Of Lipids (CONTROL) study evaluated how statins can regulate lipoprotein metabolism with OCA treatment in patients with NASH.

METHODS

This randomized, double-blind, placebo-controlled, phase 2 study began with a 5-week screening/statin washout; 84 patients with NASH were randomly assigned (1:1:1:1) to receive placebo or 5 mg, 10 mg or 25 mg OCA once daily during the 16-week double-blind phase. Concurrent once daily atorvastatin (10 mg/days) was initiated at Week 4 with subsequent titration. Enrolled patients had biopsy-confirmed diagnosis of NASH with no evidence of hepatic decompensation. Plasma was collected to analyse lipoprotein parameters.

RESULTS

At Week 4, all OCA groups had an increase from baseline in mean low-density lipoprotein cholesterol (LDLc) and mean LDL particle concentration (LDLpc), mostly owing to large, less atherogenic LDLc particles. Atorvastatin 10 mg decreased LDLc and LDLpc levels below baseline in all OCA groups by Week 8; higher doses did not provide additional clinical benefits.

CONCLUSIONS

The CONTROL study showed that OCA-induced increases in LDLc in patients with NASH were mitigated with atorvastatin. The combination of OCA and atorvastatin was generally safe and well tolerated (NCT02633956).

Combined effect of a farnesoid X receptor agonist and dipeptidyl peptidase-4 inhibitor on hepatic fibrosis

AIM

Non-alcoholic steatohepatitis (NASH) has a broad clinicopathological spectrum (inflammation to severe fibrosis). The farnesoid X receptor agonist obeticholic acid (OCA) ameliorates the histological features of NASH; satisfactory antifibrotic effects have not yet been reported. Here, we investigated the combined effects of OCA + a dipeptidyl peptidase-4 inhibitor (sitagliptin) on hepatic fibrogenesis in a rat model of NASH.

METHODS

Fifty Fischer 344 rats were fed a choline-deficient L-amino-acid-defined (CDAA) diet for 12 weeks. The in vitro and in vivo effects of OCA + sitagliptin were assessed along with hepatic fibrogenesis, lipopolysaccharide-Toll-like receptor 4 (TLR4) regulatory cascade and intestinal barrier function. Direct inhibitory effects of OCA + sitagliptin on activated hepatic stellate cells (Ac-HSCs) were assessed in vitro.

RESULTS

Treatment with OCA + sitagliptin potentially inhibited hepatic fibrogenesis along with Ac-HSC proliferation and hepatic transforming growth factor (TGF)-β1, α1(I)-procollagen, and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA expression and hydroxyproline levels. Obeticholic acid inhibited hepatic TLR4 expression and increased hepatic matrix metalloproteinase-2 expression. Obeticholic acid decreased intestinal permeability by ameliorating CDAA diet-induced zonula occludens-1 disruption, whereas sitagliptin directly inhibited Ac-HSC proliferation. The in vitro suppressive effects of OCA + sitagliptin on TGF-β1 and α1(I)-procollagen mRNA expression and p38 phosphorylation in Ac-HSCs were almost consistent. Sitagliptin directly inhibited the regulation of Ac-HSC.

CONCLUSIONS

Treatment with OCA + sitagliptin synergistically affected hepatic fibrogenesis by counteracting endotoxemia induced by intestinal barrier dysfunction and suppressing Ac-HSC proliferation. Thus, OCA + sitagliptin could be a promising therapeutic strategy for NASH.

New treatments/targets for primary biliary cholangitis

Primary biliary cholangitis (PBC) is an autoimmune, cholestatic, chronic liver disease that ultimately progresses towards cirrhosis and liver failure if untreated. While ursodeoxycholic acid has been established as standard of care for PBC in the last few decades, significant advances in second-line treatment options have recently been made and new therapeutic developments are currently under evaluation. The purpose of this article is to provide the clinician with an overview of the current treatment options and future opportunities for patients with PBC.

Farnesoid X Receptor Activation by Obeticholic Acid Elevates Liver Low-Density Lipoprotein Receptor Expression by mRNA Stabilization and Reduces Plasma Low-Density Lipoprotein Cholesterol in Mice

Objective- The objective of this study was to determine whether and how activation of farnesoid X receptor (FXR) by obeticholic acid (OCA), a clinical FXR agonist, modulates liver low-density lipoprotein receptor (LDLR) expression under normolipidemic conditions. Approach and Results- Administration of OCA to chow-fed mice increased mRNA and protein levels of LDLR in the liver without affecting the sterol-regulatory element binding protein pathway. Profiling of known LDLR mRNA-binding proteins demonstrated that OCA treatment did not affect expressions of mRNA degradation factors hnRNPD (heterogeneous nuclear ribonucleoprotein D) or ZFP36L1 but increased the expression of Hu antigen R (HuR) an mRNA-stabilizing factor. Furthermore, inducing effects of OCA on LDLR and HuR expression were ablated in Fxr^-/- mice. To confirm the post-transcriptional mechanism, we used transgenic mice (albumin-luciferase-untranslated region) that express a human LDLR mRNA 3' untranslated region luciferase reporter gene in the liver. OCA treatment led to significant rises in hepatic bioluminescence signals, Luc-untranslated region chimeric mRNA levels, and endogenous LDLR protein abundance, which were accompanied by elevations of hepatic HuR mRNA and protein levels in OCA-treated transgenic mice. In vitro studies conducted in human primary hepatocytes and HepG2 cells demonstrated that FXR activation by OCA and other agonists elicited the same inducing effect on LDLR expression as in the liver of normolipidemic mice. Furthermore, depletion of HuR in HepG2 cells by short interfering RNA transfection abolished the inducing effect of OCA on LDLR expression. Conclusions- Our study is the first to demonstrate that FXR activation increases LDLR expression in liver tissue by a post-transcriptional regulatory mechanism involving LDLR mRNA-stabilizing factor HuR.

Pharmacologic management of primary sclerosing cholangitis: what's in the pipeline?

Introduction: Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by biliary inflammation, fibrosis, and stricturing. Although considered progressive, its course is difficult to predict, and there is currently no definitive therapy shown to alter disease course and prevent death or the need for liver transplantation. Areas covered: There are multiple agents in the pipeline targeting various pathways hypothesized to lead to and drive this disease. Some are already used for other treatment indications, including antibiotics such as oral vancomycin, metronidazole, and minocycline. Other agents including obeticholic acid, nor-ursodeoxycholic acid, and monoclonal antibodies are also under investigation. This narrative review focuses on the most recent published clinical trials available for discussion. We attempt to summarize the data on current and future treatment options. Expert opinion: The rarity of this condition and poor understanding of its pathophysiology have created a void for safe and effective treatment options to alter mortality or transplant free survival. Nevertheless, some agents currently being tested have demonstrated therapeutic potential. We await validation and prospective data on these agents in hopes of modifying the disease course for patients in the future.

Guideline review: British Society of Gastroenterology/UK-PBC Primary Biliary Cholangitis treatment and management guidelines

New guidelines have been produced for the management of primary biliary cholangitis, an infrequent but nonetheless important autoimmune liver disease. We provide a succient commentary and overview of the key features of disease management that arise from these recent guideline recommendations, with a focus on therapy with licensed agents (ursodeoxycholic acid and obeticholic acid) as well as personalised management of disease complications and associated symptoms.

Human Multilineage 3D Spheroids as a Model of Liver Steatosis and Fibrosis

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in western countries. Despite the high prevalence of NAFLD, the underlying biology of the disease progression is not clear, and there are no approved drugs to treat non-alcoholic steatohepatitis (NASH), the most advanced form of the disease. Thus, there is an urgent need for developing advanced in vitro human cellular systems to study disease mechanisms and drug responses. We attempted to create an organoid system genetically predisposed to NAFLD and to induce steatosis and fibrosis in it by adding free fatty acids. We used multilineage 3D spheroids composed by hepatocytes (HepG2) and hepatic stellate cells (LX-2) with a physiological ratio (24:1). HepG2 and LX-2 cells are homozygotes for the PNPLA3 I148M sequence variant, the strongest genetic determinant of NAFLD. We demonstrate that hepatic stellate cells facilitate the compactness of 3D spheroids. Then, we show that the spheroids develop accumulations of fat and collagen upon exposure to free fatty acids. Finally, this accumulation was rescued by incubating spheroids with liraglutide or elafibranor, drugs that are in clinical trials for the treatment of NASH. In conclusion, we have established a simple, easy to handle, in vitro model of genetically induced NAFLD consisting of multilineage 3D spheroids. This tool may be used to understand molecular mechanisms involved in the early stages of fibrogenesis induced by lipid accumulation. Moreover, it may be used to identify new compounds to treat NASH using high-throughput drug screening.

Practical strategies for pruritus management in the obeticholic acid-treated patient with PBC: proceedings from the 2018 expert panel

Background and aims

This article provides expert guidance on the management of pruritus symptoms in patients receiving obeticholic acid (OCA) as treatment for primary biliary cholangitis (PBC). PBC is a chronic, autoimmune cholestatic liver disease that affects intrahepatic bile ducts. If not adequately treated, PBC can lead to cholestasis and end-stage liver disease, which may require transplant. Timely treatment is therefore vital to patient health. Pruritus is a common symptom in patients with PBC. Additionally, the use of OCA to treat PBC can contribute to increased pruritus severity in some patients, adding to patient discomfort, decreasing patient quality of life (QoL), and potentially affecting patient adherence to OCA treatment.

Methods

In May 2018, a group of physician experts from the fields of gastroenterology, hepatology, and psychiatry met to discuss the management of pruritus in OCA-treated patients with PBC. Recognizing the importance of optimizing treatment for PBC, these experts developed recommendations for managing pruritus symptoms in the OCA-treated PBC patient based on their experience in clinical practice.

Results

These recommendations include a comprehensive list of management strategies (including over-the-counter, prescription, and alternative therapies), guidance on titration of OCA to minimize pruritus severity, and an algorithm that outlines a practical approach to follow up with patients receiving OCA, to better assess and manage pruritus symptoms.

Conclusions

Pruritus associated with OCA therapy is dose dependent and often manageable, and with the proper education and tools, most pruritus cases can be effectively managed to minimize treatment discontinuation.

Obeticholic Acid: A New Era in the Treatment of Nonalcoholic Fatty Liver Disease

The main treatments for patients with nonalcoholic fatty liver disease (NAFLD) are currently based on lifestyle changes, including ponderal decrease and dietary management. However, a subgroup of patients with nonalcoholic steatohepatitis (NASH), who are unable to modify their lifestyle successfully, may benefit from pharmaceutical support. Several drugs targeting pathogenic mechanisms of NAFLD have been evaluated in clinical trials for the treatment of NASH. Farnesoid X receptor (FXR) is a nuclear key regulator controlling several processes of the hepatic metabolism. NAFLD has been proven to be associated with abnormal FXR activity. Obeticholic acid (OCA) is a first-in-class selective FXR agonist with anticholestatic and hepato-protective properties. Currently, OCA is registered for the treatment of primary biliary cholangitis. However, promising effects of OCA on NASH and its metabolic features have been reported in several studies.