Cost-Effectiveness of Rifaximin Treatment in Patients with Hepatic Encephalopathy.

BACKGROUND: Hepatic encephalopathy (HE) is a complication of cirrhosis of the liver causing neuropsychiatric abnormalities. Clinical manifestations of overt HE result in increased health care resource utilization and effects on patient quality of life. While lactulose has historically been the mainstay of treatment for acute HE and maintenance of remission, there is an unmet need for additional therapeutic options with a favorable adverse event profile. Compared with lactulose alone, rifaximin has demonstrated proven efficacy in complete reversal of HE and reduction in the incidence of HE recurrence, mortality, and hospitalizations. Evidence suggests the benefit of long-term prophylactic therapy with rifaximin; however, there is a need to assess the economic impact of rifaximin treatment in patients with HE. OBJECTIVE: To assess the incremental cost-effectiveness of rifaximin ± lactulose versus lactulose monotherapy in patients with overt HE. METHODS: A Markov model was developed in Excel with 4 health states (remission, overt HE, liver transplantation, and death) to predict costs and outcomes of patients with HE after initiation of maintenance therapy with rifaximin ± lactulose to avoid recurrent HE episodes. Cost-effectiveness of rifaximin was evaluated through estimation of incremental cost per quality-adjusted life-year (QALY) or life-year (LY) gained. Analyses were conducted over a lifetime horizon. One-way deterministic and probabilistic sensitivity analyses were conducted to assess uncertainty in results. RESULTS: The rifaximin ± lactulose regimen provided added health benefits despite an additional cost versus lactulose monotherapy. Model results showed an incremental benefit of $29,161 per QALY gained and $27,762 per LY gained with rifaximin ± lactulose versus lactulose monotherapy. Probabilistic sensitivity analyses demonstrated that the rifaximin ± lactulose regimen was cost-effective ~99% of the time at a threshold of $50,000 per QALY/LY gained, which falls within the commonly accepted threshold for incremental cost-effectiveness. CONCLUSIONS: The clinical benefit of rifaximin, combined with an acceptable economic profile, demonstrates the advantages of rifaximin maintenance therapy as an important option to consider for patients at risk of recurrent HE. DISCLOSURES: This analysis was funded by Salix Pharmaceuticals, a division of Bausch Health US. Salix and Xcenda collaborated on the methods, and Salix, Xcenda, Jesudian, and Ahmad collaborated on the writing of the manuscript and interpretation of results. Bozkaya and Migliaccio-Walle are employees of Xcenda. Ahmad reports speaker fees from Salix Pharmaceuticals, unrelated to this study. Jesudian reports consulting and speaker fees from Salix Pharmaceuticals, unrelated to this study. The results from this model were presented at AASLD: The Liver Meeting 2014; November 7-11; Boston, MA.

Pharmacotherapy for hepatic encephalopathy.

Hepatic encephalopathy (HE) is a challenging clinical complication of liver dysfunction with a wide spectrum of neuropsychiatric abnormalities that range from mild disturbances in cognitive function and consciousness to coma and death. The pathogenesis of HE in cirrhosis is complex and multifactorial, but a key role is thought to be played by circulating gut-derived toxins of the nitrogenous compounds, most notably ammonia. Therapeutic treatment options for HE are currently limited and have appreciable risks and benefits associated with their use. Management of HE primarily involves avoidance of precipitating factors, limitation of dietary protein intake, and administration of various ammonia-lowering therapies such as non-absorbable disaccharides and select antimicrobial agents. Non-absorbable disaccharides, such as lactulose, have traditionally been regarded as first-line pharmacotherapy for patients with HE. However, multiple adverse events have been associated with their use. In addition, recent literature has questioned the true efficacy of the disaccharides for this indication. Neomycin, metronidazole and vancomycin may be used as alternative treatments for patients intolerant or unresponsive to non-absorbable disaccharides. Antimicrobials reduce bacterial production of ammonia and other bacteria-derived toxins through suppression of intestinal flora. Neomycin has been reported to be as effective as lactulose, and similar efficacy has been reported with vancomycin and metronidazole for the management of HE. However, the adverse effects frequently associated with these antimicrobials limit their use as first-line pharmacological agents. Neomycin is the most commonly used antimicrobial for HE and, although poorly absorbed, systemic exposure to the drug in sufficient amounts causes hearing loss and renal toxicity. Long-term neomycin therapy requires annual auditory testing and continuous monitoring of renal function. Long-term use of metronidazole has been associated with neurotoxicity in patients with cirrhosis, including dose-dependent peripheral neuropathy. Vancomycin may be a safer option for HE in patients with chronic liver disease; however, limited experience, possible bacterial overgrowth and risk for enteric bacteria resistance preclude the routine use of vancomycin for HE. Rifaximin is a novel antimicrobial agent with a wide spectrum of activity that has shown promise as an alternative antimicrobial treatment option for HE. Several clinical trials have compared rifaximin to the disaccharides, lactulose and lactitol, and the antimicrobial neomycin. Rifaximin appears to be at least as effective as conventional drug therapy and has been associated with fewer adverse effects due to its limited systemic absorption. The available clinical data appear to support a favourable benefit-risk ratio for rifaximin, which has shown efficacy with an improved tolerability profile. Future studies are needed in order to truly characterize its cost effectiveness in today's healthcare environment. Other less frequently utilized alternative treatment options include administration of benzodiazepine receptor antagonists, branched-chain amino acids, ornithine aspartate, zinc supplementation, sodium benzoate, dopamine receptor agonists, acarbose and probiotics. Presently, there is relatively limited clinical data supporting their routine use in HE.

Nightly high dose lactulose infusion could be a cost-effective treatment for hepatic encephalopathy, renal insufficiency and heart failure.

Lactulose is an established remedy for hepatic encephalopathy and shows efficacy for chronic renal insufficiency, reducing volume overload, uremia and hyperkalemia. Potentially lactulose could also be used for non-diuretic treatment of congestive heart failure. However, use of lactulose is limited by diarrhea and flatulence. Chronic lactulose administration might be tolerable if it was accomplished by nocturnal infusion through a percutaneous duodenostomy tube, also placing a rectal foley each night following a clearing enema so that large volumes of liquid stool could be passed while patients sleep. Each morning the duodenostomy would be clamped and the foley removed. For acute patients without duodenostomies, a temporary dobhoff feeding tube with accompanying rectal foley could be employed. Patients who did not want a rectal foley could elect to have a permanent colostomy. Clinical trials could establish the relationship between lactulose infusion and clearance of water, salt, potassium, hydrogen, urea and other wastes, and compare efficacy, cost and tolerability with that of peritoneal dialysis and ultrafiltration. Lactulose could potentially allow inexpensive home-based therapy for hepatic encephalopathy, chronic renal failure and congestive heart failure, and might be life-saving in countries where renal replacement in any form is currently unavailable.

Review article: the current pharmacological therapies for hepatic encephalopathy.

Effective treatment options for hepatic encephalopathy are limited. Based on the principle that intestinal-derived ammonia contributes to the pathogenesis of hepatic encephalopathy, current therapeutic approaches are directed at reducing bacterial production of ammonia and enhancing its elimination. Non-absorbable disaccharides are first-line therapy for hepatic encephalopathy, but published clinical studies evaluating their safety and efficacy are limited. Alternative therapies such as benzodiazepine receptor antagonists, branched-chain amino acids, and l-ornithine-l-aspartate also have limited clinical data supporting their use. Studies of antibiotics indicate that they are effective in the treatment of hepatic encephalopathy, but adverse effects and concerns about long-term safety have limited the widespread use of most. Rifaximin is a minimally absorbed antibiotic that concentrates in the gastrointestinal tract and is excreted mostly unchanged in faeces. It has been studied extensively in the treatment of hepatic encephalopathy and appears to confer therapeutic benefits greater than those of placebo and non-absorbable disaccharides and at least comparable with those of systemic antibiotics. Rifaximin was also well tolerated in patients with hepatic encephalopathy and is not associated with clinical drug interactions or clinically relevant bacterial antibiotic resistance. In conclusion, non-absorbed antibiotics such as rifaximin offer a favourable benefit-risk ratio in the treatment of hepatic encephalopathy and may help to improve patient outcomes.