Dosing of Rifaximin Soluble Solid Dispersion Tablets in Adults With Cirrhosis: 2 Randomized, Placebo-controlled Trials

Pharmacologic Management of Hepatic Encephalopathy

Hepatic encephalopathy is a common cause of morbidity and mortality among patients with decompensated liver cirrhosis. In this article, we review the history, mechanism, and evidence for first-line pharmacologic therapies for hepatic encephalopathy including nonabsorbable disaccharides, antibiotics, and electrolyte management. We also review newer, second-line therapies including polyethylene glycol, albumin, branched-chain amino acids, probiotics and fecal microbiota transplant, zinc, and l-ornithine-l-aspartate.

Future Therapies of Hepatic Encephalopathy

Hepatic encephalopathy, either covert or overt, affects more than half of patients with cirrhosis and has lasting effects even after portal hypertension is corrected. Unfortunately, the current therapeutic options still result in high rates of relapse and progression, in part owing to cost barriers and side effects, leading to poor adherence. This review summarizes emerging treatment options, which could take advantage of alternative disease pathways to improve future care of those with hepatic encephalopathy.

Preventive and therapeutic effects of rifaximin on hepatic encephalopathy with differential application dosages and strategies: a network meta-analysis

BACKGROUND

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that affects the prognosis of patients with liver disease and is considered an independent risk factor for hospitalization and death. Rifaximin has been approved for HE treatment. This review will analyze the effect of rifaximin on different stages of HE with differential application dosages and strategies by traditional and network meta-analyses.

METHODS

We performed a systematic search of PubMed, EmBase, and Cochrane Library databases up to February 26, 2023, to identify randomized controlled trials (RCTs) about rifaximin for the prevention and treatment of HE. The outcomes included incidence of HE and HE progression, HE reversal, mortality, and adverse effects.

RESULTS

A total of 21 studies were included. In the primary prevention of HE, rifaximin significantly reduced the incidence of HE (OR: 0.66; 95% CI: 0.45, 0.96; p = 0.032). In secondary prevention, rifaximin significantly reduced the risk of recurrence in patients who were in remission (OR: 0.38; 95% CI: 0.28, 0.52; p < 0.001). In the treatment of minimal HE, rifaximin significantly reduced the breakthrough of MHE to OHE (OR: 0.17; 95% CI: 0.04,0.63; p = 0.008). Rifaximin also significantly improved the clinical symptoms of MHE and OHE patients (OR: 3.76; 95% CI: 2.69, 5.25; p < 0.001). However, rifaximin did not reduce mortality at any stage in HE patients (OR: 0.79; 95% CI: 0.58, 1.08; p = 0.133). Additionally, rifaximin did not increase the risk of adverse effects (OR: 0.96; 95% CI: 0.74, 1.24; p = 0.749). In the network meta-analysis, the 400 mg T.I.D. intervention had a relative advantage for HE risks in primary and secondary prevention. In the treatment of MHE, 600 mg b.i.d. was superior in preventing the breakthrough from MHE to OHE.

CONCLUSION

Rifaximin prevented HE risks and progression and improved clinical symptoms in patients with MHE but did not reduce mortality. For primary and secondary prevention, 400 mg t.i.d. could be considered. 600 mg b.i.d. could be considered in patients with MHE.

Serum Ammonia Levels Do Not Correlate With Overt Hepatic Encephalopathy Severity in Hospitalized Patients With Cirrhosis

Although ammonia is involved in the pathophysiology of hepatic encephalopathy (HE), the use of ammonia levels in clinical practice is problematic.1-3 For example, in a study of 551 patients with overt HE (OHE) receiving lactulose who had ammonia levels tested, only 60% had an increased ammonia level (defined as >72 μmol/L).2 Overall, there was no correlation observed between lactulose dose and whether ammonia levels were obtained (ie, presence/absence of increased ammonia level did not guide therapy), or between time to OHE resolution and ammonia levels.2 Additionally, there is substantial interlaboratory variability in sample handling and processing, which may affect ammonia measurements.4.

The RIVET RCT: Rifamycin SV MMX improves muscle mass, physical function, and ammonia in cirrhosis and minimal encephalopathy

BACKGROUND

Minimal hepatic encephalopathy (MHE) negatively affects the prognosis of cirrhosis, but treatment is not standard. Rifamycin SV MMX (RiVM) is a nonabsorbable rifampin derivative with colonic action.

METHODS

In a phase 2 placebo-controlled, double-blind randomized clinical trial patients with MHE were randomized to RiVM or placebo for 30 days with a 7-day follow-up. The primary endpoint was a change in stool cirrhosis dysbiosis ratio. Gut-brain (cognition, stool/salivary microbiome, ammonia, brain magnetic resonance spectroscopy), inflammation (stool calprotectin/serum cytokines), patient-reported outcomes (sickness impact profile: total/physical/psychosocial, high = worse), and sarcopenia (handgrip, bioelectric impedance) were secondary. Between/within groups and delta (post-pre) comparisons were performed.

RESULTS

Thirty patients (15/group) were randomized and completed the study without safety concerns. While cirrhosis dysbiosis ratio was statistically similar on repeated measures ANOVA (95% CI: -0.70 to 3.5), ammonia significantly reduced (95% CI: 4.4-29.6) in RiVM with changes in stool microbial α/β-diversity. MHE status was unchanged but only serial dotting (which tests motor strength) improved in RiVM-assigned patients. Delta physical sickness impact profile (95% CI: 0.33 = 8.5), lean mass (95% CI: -3.3 to -0.9), and handgrip strength (95% CI: -8.1 to -1.0) improved in RiVM versus placebo. Stool short-chain fatty acids (propionate, acetate, and butyrate) increased post-RiVM. Serum, urine, and stool bile acid profile changed to nontoxic bile acids (higher hyocholate/ursodeoxycholate and lower deoxycholate/lithocholate) post-RiVM. Serum IL-1β and stool calprotectin decreased while brain magnetic resonance spectroscopy showed higher glutathione concentrations in RiVM.

CONCLUSIONS

RiVM is well tolerated in patients with MHE with changes in stool microbial composition and function, ammonia, inflammation, brain oxidative stress, and sarcopenia-related parameters without improvement in cognition. RiVM modulates the gut-brain axis and gut-muscle axis in cirrhosis.

Efficacy and Safety of Variable Treatment Options in the Prevention of Hepatic Encephalopathy: A Systematic Review and Network Meta-Analysis

There are no guidelines for the most effective medication to reduce hepatic encephalopathy (HE) or the associated mortality. The purpose of this study is to determine the most effective possible treatment among the single treatment options or the combined treatment options for decreasing the morbidity and mortality of HE. We evaluated the outcomes by various parameters such as the quality of life, reduction in ammonia, all causes of mortality, adverse events, reversal of minimal HE, and development of overt HE. We systematically searched PubMed, Cochrane, Web of Science, and Scopus till the 19th of January 2023 for studies that assess various treatment options for HE. Data were extracted from eligible studies and pooled in a frequentist network meta-analysis as standardized mean difference (SMD) and their 95% confidence interval (CI) using the MetaInsight web-based tool. The Cochrane Tool was used to assess the randomized controlled trials' quality (RCT), while the NIH tool was used to assess the quality of the included cohort studies. Utilizing the R software, the network meta-analysis was conducted. In addition to a significant variation in cases of (Lactulose and Rifaximin) compared with Rifaximin (RR= 0.39, 95% CI [0.17; 0.89]), the results demonstrated a significantly lower incidence of overt HE in (Lactulose and Rifaximin) compared with placebo (RR=0.19, 95% CI [0.09; 0.40]). Most arms demonstrated a statistically significant reduction in the incidence of overt HE compared to albumin and placebo. The results also demonstrated a significant reduction in ammonia between L-ornithine-L-aspartate (LOLA) and probiotics (MD= -19.17, 95% CI [-38.01; -0.32]), as well as a significant difference in the incidence of LOLA compared to placebo (MD= -22.62, 95% CI [-39.16; -6.07]). This network meta-analysis has significant data for managing subclinical HE in people without a history of overt HE. Our analysis showed that (Lactulose and Rifaximin), followed by (Rifaximin and L-carnitine), followed by (Lactulose and Rifaximin with zinc) were the best combinations regarding overt HE. LOLA reduced ammonia best, followed by Nitazoxanide and finally Lactulose. (Lactulose and Nitazoxanide) have the least adverse effects, followed by (Rifaximin and L-carnitine), then Probiotics. Yet, all mortality outcomes and quality of life changes yielded no useful findings. Future studies like RCTs must be done to compare our therapies directly.

Rifaximin Reduces Risk of All-Cause Hospitalization in Cirrhotic Liver Transplant Candidates with Hepatic Encephalopathy

In cirrhotic patients listed for liver transplantation (LT) with a history of hepatic encephalopathy (HE), rifaximin reduces the number of hospitalizations, but whether it influences the time to first hospitalization is unknown.

AIMS

to evaluate the time-dependent impact of rifaximin on the risk of all-cause hospitalization and dropout in patients on the LT waiting list.

METHODS

Consecutive patients listed for LT were retrospectively enrolled. After balancing populations with and without rifaximin treatment using the inverse probability therapy weighting analysis, Fine-Gray multivariable competing risk analyses were run to explore risk factors for the first episode of hospitalization and dropout.

RESULTS

When comparing 92 patients taking rifaximin to the untreated group of 152, rifaximin treatment was not associated with any of the study outcomes. In the subset of patients with a history of HE at waitlist entry (N = 81 rifaximin-treated and N = 39 untreated), rifaximin intake was independently associated with a lower risk of hospitalization for all causes (SHR 0.638; 95.0% CI 0.418-0.973; p = 0.037) and for HE (SHR 0.379; 95.0% CI 0.207-0.693; p = 0.002).

CONCLUSIONS

cirrhotic LT candidates with a prior history of HE rifaximin treatment are associated with a lower risk of time-dependent all-cause hospitalization, likely due to its unique effect on gut microbiome composition/function.

Gut Microbiome-Centered Therapies for Alcohol-Associated Liver Disease

Globally, liver disease caused by alcohol is becoming more prevalent each year. Misuse of alcohol causes a spectrum of liver diseases, such as liver steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. The cornerstone of treatment is abstinence from alcohol. In spite of this, available treatment for alcohol-associated liver disease (ALD) shows limited effectiveness currently. There are numerous ways in which alcohol disrupts the gut-liver axis, including dysbiosis of the gut microbiome, disruption of mucus and epithelial cell barriers, impaired production of antimicrobial molecules, and dysfunction of the immune system, causing translocation of viable microbes and microbial products to the liver and systemic circulation. Microbial exposure results in not only inflammation and progression of liver disease but also infections in late-stage ALD. This led scientists to focus their therapeutic strategies and targets for ALD on the gut microbiome. Throughout this review, we address the role of gut microbiome-centered therapeutic approaches for ALD focusing predominantly on randomized controlled trials. We will summarize the latest clinical trials using probiotics, antibiotics, and fecal microbial transplants in modulating the gut-liver axis and for improvement of ALD.

Update in the Treatment of the Complications of Cirrhosis

Cirrhosis consists of 2 main stages: compensated and decompensated, the latter defined by the development/presence of ascites, variceal hemorrhage, and hepatic encephalopathy. The survival rate is entirely different, depending on the stage. Treatment with nonselective β-blockers prevents decompensation in patients with clinically significant portal hypertension, changing the previous paradigm based on the presence of varices. In patients with acute variceal hemorrhage at high risk of failure with standard treatment (defined as those with a Child-Pugh score of 10-13 or those with a Child-Pugh score of 8-9 with active bleeding at endoscopy), a pre-emptive transjugular intrahepatic portosystemic shunt (TIPS) improves the mortality rate and has become the standard of care in many centers. In patients with bleeding from gastrofundal varices, retrograde transvenous obliteration (in those with a gastrorenal shunt) and/or variceal cyanoacrylate injection have emerged as alternatives to TIPS. In patients with ascites, emerging evidence suggests that TIPS might be used earlier, before strict criteria for refractory ascites are met. Long-term albumin use is under assessment for improving the prognosis of patients with uncomplicated ascites and confirmatory studies are ongoing. Hepatorenal syndrome is the least common cause of acute kidney injury in cirrhosis, and first-line treatment is the combination of terlipressin and albumin. Hepatic encephalopathy has a profound impact on the quality of life of patients with cirrhosis. Lactulose and rifaximin are first- and second-line treatments for hepatic encephalopathy, respectively. Newer therapies such as L-ornithine L-aspartate and albumin require further assessment.

Prediction and prevention of the first episode of overt hepatic encephalopathy in patients with cirrhosis

Hepatic encephalopathy (HE) is one of the most important complications of patients with liver cirrhosis. In addition, HE is associated with a dismal prognosis and has detrimental effects on patients' quality of life. Thus, it is of pivotal importance to identify patients at high risk for overt HE (OHE) in whom primary prophylaxis may be justified. In this narrative review, we aim to provide insight into predictors and prediction tools for a first-time episode of OHE and to scrutinize the current level of evidence of primary prophylaxis. In recent decades, several cognitive tests, composite scores, and blood-based biomarkers have been demonstrated to be predictive of a first-time episode of OHE. Among the best validated are the established tests for minimal HE, such as the Psychometric Hepatic Encephalopathy Score, determination of the critical flicker frequency, Stroop EncephalApp, or the Animal Naming Test. Individualized risk stratification using blood-based biomarkers and cross-sectional imaging (sarcopenia and spontaneous portosystemic shunts) is coming to the fore, but validation in larger multicenter cohorts is often lacking. On the basis of current evidence, a recommendation for primary prophylaxis of a first episode of OHE cannot be made in general. Only 2 studies have investigated the prevention of a first-time OHE episode as the primary endpoint. In this narrative review, we provide a concise overview of the current evidence levels on prediction tools and pharmacological prevention of a first episode of OHE. In addition, we give an outlook on future research targets to improve knowledge on this important topic.

Active Clinical Trials in Hepatic Encephalopathy: Something Old, Something New and Something Borrowed

Hepatic encephalopathy (HE) is a potentially reversible neurocognitive syndrome that occurs in patients with acute or chronic liver disease. Currently, most of the therapies for HE aim to reduce ammonia production or increase its elimination. To date, only two agents have been approved as treatments for HE: lactulose and rifaximin. Many other drugs have also been used, but data to support their use are limited, preliminary or lacking. The aim of this review is to provide an overview and discussion of the current development of treatments for HE. Data from ongoing clinical trials in HE were obtained from the ClinicalTrials.gov website, and a breakdown analysis of studies that were active on August 19th, 2022, was performed. Seventeen registered and ongoing clinical trials for therapeutics targeting HE were identified. More than 75% of these agents are in phase II (41.2%) or in phase III (34.7%). Among them, there are many old acquaintances in the field, such as lactulose and rifaximin, some new entries such as fecal microbiota transplantation and equine anti-thymocyte globulin, an immunosuppressive agent, but also some therapies borrowed from other conditions, such as rifamycin SV MMX and nitazoxanide, two antimicrobial agents FDA approved for the treatment of some types of diarrheas or VE303 and RBX7455, two microbiome restoration therapies, currently used as treatment of high-risk Clostridioides difficile infections. If working, some of these drugs could soon be used as valid alternatives to current therapies when ineffective or be approved as novel therapeutic approaches to improve the quality of life of HE patients.

Gut microbiome-brain-cirrhosis axis

Cirrhosis is characterized by inflammation, degeneration, and fibrosis of liver tissue. Along with being the most common cause of liver failure and liver transplant, cirrhosis is a significant risk factor for several neuropsychiatric conditions. The most common of these is HE, which is characterized by cognitive and ataxic symptoms, resulting from the buildup of metabolic toxins with liver failure. However, cirrhosis patients also show a significantly increased risk for neurodegenerative diseases such as Alzheimer and Parkinson diseases, and for mood disorders such as anxiety and depression. In recent years, more attention has been played to communication between the ways the gut and liver communicate with each other and with the central nervous system, and the way these organs influence each other's function. This bidirectional communication has come to be known as the gut-liver-brain axis. The gut microbiome has emerged as a key mechanism affecting gut-liver, gut-brain, and brain-liver communication. Clinical studies and animal models have demonstrated the significant patterns of gut dysbiosis when cirrhosis is present, both with or without concomitant alcohol use disorder, and have provided compelling evidence that this dysbiosis also influences the cognitive and mood-related behaviors. In this review, we have summarized the pathophysiological and cognitive effects associated with cirrhosis, links to cirrhosis-associated disruption of the gut microbiome, and the current evidence from clinical and preclinical studies for the modulation of the gut microbiome as a treatment for cirrhosis and associated neuropsychiatric conditions.