Characterisation and utility of thiopurine methyltransferase and thiopurine metabolite measurements in autoimmune hepatitis

Response to azathioprine treatment in autoimmune hepatitis is dependent on glutathione transferase genotypes

BACKGROUND

Azathioprine (AZA) is part of the standard treatment for autoimmune hepatitis (AIH). The first step in the complex bioconversion of AZA to active metabolites is mediated by glutathione transferases (GSTs).

AIMS

Elucidate the association between GSTM1 and GSTT1 copy number variation (CNV), genetic variation in GSTA2, GSTP1, and inosine-triphosphate-pyrophosphatase, and the response to AZA in AIH.

METHODS

Genotyping was performed in AIH patients (n = 131) on AZA, and in a Swedish background population (n = 283). Thiopurine metabolites in blood erythrocytes were determined by high performance liquid chromatography.

RESULTS

GSTM1 and GSTT1 CNV were associated with treatment response to AZA. Gene deletion of GSTM1-but not of GSTT1-was associated with the liver transaminase levels. None of the studied genetic variants were associated with the thiopurine metabolite concentrations, suggesting non-enzymatic mechanisms of GSTM1 and GSTT1 in the context of AZA efficacy in AIH. The prevalence of GSTM1 and GSTT1 CNV genotypes was similar in AIH and in the background population.

CONCLUSION

This study shows the effects of GSTM1 and GSTT1 CNV on AZA efficacy in AIH, not previously described. It also elaborates on the impact of the definition of treatment response, on the importance of the various GSTs studied. Furthermore, the GSTM1 and GSTT1 CNV frequencies previously reported in European populations were confirmed.

British Society of Gastroenterology guidelines for diagnosis and management of autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease which, if untreated, often leads to cirrhosis, liver failure and death. The last British Society of Gastroenterology (BSG) guideline for the management of AIH was published in 2011. Since then, our understanding of AIH has advanced in many areas. This update to the previous guideline was commissioned by the BSG and developed by a multidisciplinary group. The aim of this guideline is to review and summarise the current evidence, in order to inform and guide diagnosis and management of patients with AIH and its variant syndromes. The main focus is on AIH in adults, but the guidelines should also be relevant to older children and adolescents.

Forty years of successful national research collaboration in liver disease - the Swedish experience

AIM

Sweden has historically provided a fruitful arena for research in clinical medicine. We here share 40 years of experience of collaboration in the Swedish hepatology research group (SWEHEP) (https://www.swehep.se).

METHODS

We describe the way the Swedish hepatology pioneers started the group and how the network continuously developed over the years. Successful projects such as thorough studies of natural history and various clinical aspects of autoimmune hepatitis, primary biliary cholangitis, primary sclerosing cholangitis, and steatosis are described.

RESULTS

Over the years, more than 80 publications have been published by the group. A summary of new and ongoing research programs includes the randomized placebo-controlled trial of simvastatin in PSC (PiSCATIN), the prospective BIGMAP (Biochemical and genetic markers for the assessment and prognostication of liver cirrhosis) initiative in patients with liver cirrhosis, and the DETECT-HCC, a prospective multicenter cohort study comparing abbreviated MRI and ultrasound for surveillance of hepatocellular carcinoma every six months over two years. The group philosophy, success factors for the longstanding collaboration as well as experience of failures are shared.

CONCLUSION

The success of hepatology research in Sweden is based on longstanding collaboration over generations of hepatologists, where everyone contributes, regular research meetings, mutual trust, and perseverance.

Optimizing thiopurine therapy in autoimmune hepatitis: A multicenter study on monitoring metabolite profiles and co-therapy with allopurinol

BACKGROUND AND AIMS

In autoimmune hepatitis, achieving complete biochemical remission (CBR) with current weight-based thiopurine dosing is challenging. We investigated whether patients could be stratified regarding CBR according to a target range of thiopurine metabolites. Moreover, we explored the effects of azathioprine dosage increases and co-therapy of allopurinol with low-dose thiopurines on metabolite profiles and treatment response.

APPROACH AND RESULTS

The relation between metabolites and treatment response was assessed in 337 individuals from 4 European centers. In a global, cross-sectional analysis, active metabolites 6-thioguanine nucleotides (6TGN) were similar in those with and without CBR. However, analyzing patients with sequential measurements over 4 years (N = 146) revealed higher average 6TGN levels in those with stable CBR (260 pmol/0.2 mL) compared to those failing to maintain CBR (181 pmol/0.2 mL; p = 0.0014) or never achieving CBR (153 pmol/0.2 mL; p < 0.0001), with an optimal 6TGN cutoff of ≥223 pmol/0.2 mL (sensitivity: 76% and specificity: 78%). Only 42% exhibited 6TGN ≥223 pmol/0.2 mL following weight-based dosing, as doses weakly correlated with 6TGN but with 6-methylmercaptopurine (6MMP), a metabolite associated with toxicity. Azathioprine dose increases led to preferential 6MMP formation (+127% vs. 6TGN +34%; p < 0.0001). Conversely, adding allopurinol to thiopurines in difficult-to-treat patients (N = 36) raised 6TGN (168→321 pmol/0.2 mL; p < 0.0001) and lowered 6MMP (2125→184 pmol/0.2 mL; p < 0.0001), resulting in improved transaminases in all patients and long-term CBR in 75%.

CONCLUSIONS

Maintaining CBR in autoimmune hepatitis was associated with 6TGN ≥223 pmol/0.2 mL. For patients who fail to achieve CBR and therapeutic 6TGN levels despite thiopurine dose increase due to preferential 6MMP formation, comedication of allopurinol alongside low-dose thiopurines represents an efficient alternative.

Advances in the evaluation and treatment of autoimmune hepatitis

PURPOSE OF REVIEW

The primary therapy of autoimmune hepatitis (AIH) has been established for over three decades. This review focuses on updates in the evaluation and management of patients with AIH.

RECENT FINDINGS

The evaluation of patients has recently been updated to include more definitive screening for other autoimmune diseases, including thyroid disease and celiac disease. Antibody detection by ELISA, an easier and more commonly available method, has been incorporated into the latest iteration of the AIH scoring system. Corticosteroids and AZA remain the backbone of AIH treatment, but there is growing evidence for mycophenolate mofetil as both first-line and second-line therapy, and growing inquiry into calcineurin inhibitors. Noninvasive markers of liver disease have now been validated in AIH, with the strongest evidence for VCTE in patients with minimal hepatic inflammation.

SUMMARY

Recent research of alternative immunosuppressant therapies, noninvasive markers of fibrosis, and updated society guidelines, have improved our ability to evaluate, treat, and follow patients with AIH.

[Treatment of autoimmune hepatitis-First-line, second-line and third-line treatment]

Autoimmune hepatitis (AIH) is a rare autoimmune inflammation of the liver mostly with a chronic course, which can also be acutely manifested up to acute liver failure. It affects women 3-4 times more frequently than men and can be diagnosed in all age groups. In one third of the patients a liver cirrhosis is present at the time of diagnosis. It is characterized by a hepatic inflammation pattern, a polyclonal hypergammaglobulinemia of immunoglobulin G and the detection of autoantibodies. A liver biopsy is necessary to make the diagnosis. The AIH is histologically characterized in particular by a lymphoplasmacytic infiltrate in the portal fields. In cases with a relevant disease activity, AIH is typically treated by immunosuppression. The immunosuppressive treatment is associated with a prevention of disease progression to liver cirrhosis and a better survival. The success of treatment is measured by achieving biochemical remission, i.e., normalization of the transaminase and immunoglobulin G levels as a good noninvasive predictor of a histological remission. Another treatment target is an improvement of the symptoms of the patient. The first-line treatment consists of a glucocorticoid, mostly prednisolone or in cases without advanced fibrosis budesonide, and azothioprine. For reduction of steroid-specific treatment side effects the maintenance treatment should be carried out steroid-free whenever possible. In cases of insufficient response to azothioprine or side effects a treatment attempt using antimetabolites, such as 6‑mercaptopurine or mycophenolate mofetil is primarily carried out as second-line treatment. For patients who do not achieve biochemical remission through first-line or second-line treatment, a variety of medications are available for third-line treatment, e.g., rituximab, calcineurin inhibitors or antitumor necrosis factor (anti-TNF) antibodies. Third-line treatment should be carried out in expert centers and registered in the European Reference Network for Rare Liver Diseases in order to improve the currently sparse database for these forms of treatment in the future.

Treatment of Autoimmune Hepatitis

The goal of autoimmune hepatitis treatment is to achieve clinical and biochemical remission, which is associated with significantly improved outcomes. Induction treatment with corticosteroids and the subsequent addition of steroid-sparing therapy with gradual tapering of corticosteroids remains the standard of care. Several alternatives to azathioprine and second-line agents, such as mycophenolate mofetil, tacrolimus, cyclosporine, sirolimus, or rituximab, have been evaluated in those with intolerance or inadequate response to standard-of-care therapy. Treatment withdrawal is achievable in less than 20% of patients after 2 years of sustained remission. Liver transplantation should be considered in those with progressive liver disease or those with complications such as hepatocellular carcinoma.

Noninvasive biomarkers for the diagnosis and management of autoimmune hepatitis

Autoimmune hepatitis (AIH) is a rare disease of unclear etiology characterized by loss of self-tolerance that can lead to liver injury, cirrhosis, and acute liver failure. First-line treatment consists of systemic corticosteroids, or budesonide, and azathioprine, to which most patients are initially responsive, although predictors of response are lacking. Relapses are very common, correlate with histological activity despite normal serum transaminases, and increase hepatic fibrosis. Furthermore, current regimens lead to adverse effects and reduced quality of life, whereas medication titration is imprecise. Biomarkers that can predict the clinical course of disease, identify patients at elevated risk for relapse, and improve monitoring and medication dosing beyond current practice would have high clinical value. Herein, we review novel candidate biomarkers in adult and pediatric AIH based on prespecified criteria, including gene expression profiles, proteins, metabolites, and immune cell phenotypes in different stages of AIH. We also discuss biomarkers relevant to AIH from other immune diseases. We conclude with proposed future directions in which biomarker implementation into clinical practice could lead to advances in personalized therapeutic management of AIH.

[Autoimmune Hepatitis - What is important for clinical practice?]

Autoimmune hepatitis is a rare but chronic autoimmune-mediated liver disease. Key features are elevated transaminases, hypergammaglobulinemia, presence of specific autoantibodies and typical histological features. Diagnostic scores are helpful in establishing the diagnosis. Immunosuppressive therapy should be initiated in every patient with inflammatory activity. First-line therapy includes steroids and azathioprine and results in biochemical and histological remission in the majority of patients. In most cases, lifelong therapy is required. Every patient should receive regular follow-up surveillance including biochemical parameters as well as sonography and elastography.

Systematic Review and Meta-Analysis of Thiopurine Metabolite Levels and Biochemical Remission in Autoimmune Hepatitis

BACKGROUND

The utility of measuring thiopurine metabolites (TM) to individualize therapy in autoimmune hepatitis (AIH) has not been defined, and the evidence regarding its use in clinical practice is heterogeneous. This systematic review and meta-analysis aimed to compare the mean concentration of TM between patients in biochemical remission and those not in remission.

METHODS

A systematic literature search was conducted using PubMed, Scopus, the Cochrane Library, and Google Scholar for keywords related to TM and AIH. Two reviewers independently searched and selected studies comparing the levels of 6-methyl mercaptopurine (6-MMP) and 6-thioguanine nucleotide (6-TGN) and their ratio in cases of AIH in remission and otherwise. Meta-analysis was performed by calculating the weighted mean difference using the inverse variance heterogeneity model.

RESULTS

A total of 1066 records were identified through systematic search; of which, 7 (n = 3 pediatric, n = 4 adults) were considered for inclusion, and 442 TM measurements (n = 128 in children) were analyzed. Mean 6-TGN levels were significantly higher among patients in remission than in those who were not, with a pooled weighted mean difference (WMD) of 15.67 [95% confidence interval (CI), 6.68-24.66] pmol/8 × 108 red blood cells (RBC). The difference was higher in the pediatric age group (WMD, 56.11; 95% CI, 13.60-98.62) than in adults (WMD, 13.77; 95% CI, 4.58-22.97). There was no significant difference in the 6-MMP levels (WMD, -431.7; 95% CI, -1237.4 to 373.9 pmol/8 × 108 RBC; I2 = 82%; n = 3 studies) or 6-MMP/6-TGN ratio among the patients who were in biochemical remission and those who were not (WMD, -0.97; 95% CI, -5.77 to 3.84; I2 = 82%; n = 3 studies).

CONCLUSIONS

This meta-analysis suggests a link between 6-TGN levels and biochemical remission in AIH. Further high-quality studies are required to determine the therapeutic cutoff of 6-TGN.

Towards personalised medicine in autoimmune hepatitis: Measurement of thiopurine metabolites results in higher biochemical response rates

BACKGROUND & AIMS

Patients with autoimmune hepatitis (AIH) usually receive maintenance therapy with thiopurines, such as azathioprine (AZA) or mercaptopurine. Genetic polymorphisms in AZA metabolism can lead to variations in thioguanine nucleotide (TGN) and 6-methylmercaptopurine, both of which can cause adverse drug reactions (ADRs). In inflammatory bowel disease, a therapeutic TGN range (225-450 pmol/8x10⁸ erythrocytes) has been identified to optimise effectiveness. We evaluated the benefits of a personalised medicine approach to thiopurine dosing, in comparison to standard weight-based dosing.

METHODS

A retrospective matched cohort study of 214 patients with AIH who were seen at King's College between 1999-2019 was performed. Metabolite levels were measured in 109 patients. The control group included 105 patients on weight-based thiopurine dosing with no metabolite monitoring.

RESULTS

Biochemical response (BR) occurred more frequently at 6-month follow-up in patients with metabolite monitoring compared to those on a weight-based regimen (77% vs. 60%, p = 0.008). This remained true with data analysis based on clinicians who measure metabolites and those who do not (BR at 6 months: 84% vs. 64%, p = 0.016). Patients with BR had TGN levels within the therapeutic range of 225-450 pmol/8x10⁸ erythrocytes significantly more often than those who failed to achieve or lost BR (40% vs. 13%, p <0.0001). Moreover, TGN levels within the pre-defined therapeutic range predicted more stable disease within 6 months of testing compared to levels outside the range (p <0.0001). A high proportion of patients with sub-therapeutic TGN levels (75-225 pmol/8x10⁸ erythrocytes) remained in BR (75% vs. 81%, p = 0.589) with fewer ADRs (44% vs. 86%, p = 0.0002) when compared to patients with therapeutic TGN levels.

CONCLUSION

A strategy of personalised medicine using metabolite levels can optimise treatment regimens in AIH, resulting in fewer ADRs whilst maintaining BR.

LAY SUMMARY

This study looked to see if measuring the breakdown products of a medication used in autoimmune hepatitis increases the chances of gaining good control of the disease, when compared to a group of patients who were on a dose of this medication based on their weight. A group of 214 patients with autoimmune hepatitis were split into 2 groups: roughly half had their medication dose adjusted according to measurements of breakdown products in the blood, whilst the other half received their weight-based dose as normal. The results confirmed that using a personalised approach and checking drug breakdown products resulted in fewer side effects and potentially improved control of disease.

Second-line and third-line therapy for autoimmune hepatitis: A position statement from the European Reference Network on Hepatological Diseases and the International Autoimmune Hepatitis Group

Most patients with autoimmune hepatitis respond well to standard immunosuppressive therapy with steroids and azathioprine, and while untreated disease is usually fatal, patients who respond well to therapy have an excellent prognosis. However, insufficient response to standard therapy or intolerable side effects requiring dose adaptions or treatment changes occur in 10-20% of patients. While there is fairly good agreement on second-line treatment options, there is very wide variation in the indication and use of possible third-line therapies. Herein, the European Reference Network on Hepatological Diseases (ERN RARE-LIVER) and the International Autoimmune Hepatitis Group (IAIHG) outline a treatment algorithm for both children and adults that should help to standardise treatment approaches, in order to improve patient care and to enable the comparison of treatment results between scientific publications.

Review article: opportunities to improve and expand thiopurine therapy for autoimmune hepatitis

BACKGROUND

Thiopurines in combination with glucocorticoids are used as first-line, second-line and maintenance therapies in autoimmune hepatitis and opportunities exist to improve and expand their use.

AIMS

To describe the metabolic pathways and key factors implicated in the efficacy and toxicity of the thiopurine drugs and to indicate the opportunities to improve outcomes by monitoring and manipulating metabolic pathways, individualising dosage and strengthening the response.

METHODS

English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed.

RESULTS

Thiopurine methyltransferase activity and 6-tioguanine (6-thioguanine) nucleotide levels influence drug efficacy and safety, and they can be manipulated to improve treatment response and prevent myelosuppression. Methylated thiopurine metabolites are associated with hepatotoxicity, drug intolerance and nonresponse and their production can be reduced or bypassed. Universal pre-treatment assessment of thiopurine methyltransferase activity and individualisation of dosage to manipulate metabolite thresholds could improve outcomes. Early detection of thiopurine resistance by metabolite testing, accurate estimations of drug onset and strength by surrogate markers and adjunctive use of allopurinol could improve the management of refractory disease. Dose-restricted tioguanine (thioguanine) could expand treatment options by reducing methylated metabolites, increasing the bioavailability of 6-tioguanine nucleotides and ameliorating thiopurine intolerance or resistance.

CONCLUSIONS

The efficacy and safety of thiopurines in autoimmune hepatitis can be improved by investigational efforts that establish monitoring strategies that allow individualisation of dosage and prediction of outcome, increase bioavailability of the active metabolites and demonstrate superiority to alternative agents.

Autoimmune hepatitis: Current and future therapeutic options

Autoimmune hepatitis (AIH) is a rare immune-mediated liver disease with few major advances in treatment options over the last several decades. Available options are effective in most patients albeit are imprecise in their mechanisms. Novel and more tolerable induction regimens and alternative options for management of patients intolerant or with suboptimal response to traditional therapies including in the post-transplant setting remain an important unmet need. This review aims to summarize recent data on pharmacological options and investigational drugs in development for patients with AIH. Standard therapy using prednisone with or without azathioprine remains the mainstay of therapy and is effective in most patients. Budesonide may be considered for induction in early disease and in those with mild fibrosis, but has not been approved for maintenance therapy. Mycophenolate mofetil (MMF) in combination with steroids might be an alternative first-line therapy, but results from a randomized trial are awaited. MMF as a second-line maintenance agent has moderate efficacy though more frequent adverse events in patients with cirrhosis may be seen. Tacrolimus may be an equally effective second-line option particularly in non-responders, but data remain limited. Management of recurrent AIH post-liver transplantation remains controversial with insufficient data to support long-term steroid use. Moving forward, expanding the scope of therapeutic options to include biologics including B-cell depleting agents may be a promising step. Recent insights in understanding the pathogenesis of AIH could serve as a basis for future therapies, including the elucidation of different immunoregulatory pathways and the potential role of the intestinal microbiome.

NUDT15 Polymorphism Confer Increased Susceptibility to Thiopurine-Induced Leukopenia in Patients With Autoimmune Hepatitis and Related Cirrhosis

The aim of this study was to investigate the influence of NUDT15 R139C and thiopurine S-methyltransferase (TPMT) on azathioprine (AZA) induced leukopenia in patients with autoimmune hepatitis (AIH) and related cirrhosis. A total of 149 Chinese AIH patients with a history of AZA treatment were retrospectively evaluated. The clinical and epidemiological characteristics of the patients were obtained from an electronic database and reviewed. NUDT15 (rs116855232) and TPMT^∗3C (rs1142345) SNPs were genotyped using a PCR method. Twelve patients developed leukopenia, and this adverse drug reaction was significantly associated with the T risk allele in NUDT15 [P < 0.00001, odds ratio = 20.41; 95% confidence interval (CI) (7.84, 53.13)], with the sensitivity and specificity of 91.67 and 89.05%, respectively. The median maintenance dosages for patients with the rs116855232 CC and CT genotypes were 1.23 (0.95, 1.53) mg ⋅ kg⁻¹ ⋅ d⁻¹ and 0.96 (0.83, 1.19) mg ⋅ kg⁻¹ ⋅ d⁻¹, respectively (P = 0.028). In contrast, no significant association was observed for TPMT^∗3C genotypes. Notably, subgroup analysis of the 13 patients with leukopenia before therapy, these white blood cell (WBC) counts did not show further reduction after AZA treatment and maintenance dosage was 1.13 (0.94, 1.60) mg ⋅ kg⁻¹ ⋅ d⁻¹. Therefore, NUDT15 polymorphism is significantly associated with thiopurine-induced leukopenia in Chinese patients with AIH and related cirrhosis. Adjusting the AZA dosage should be considered in patients according to the NUDT15 R139C genotypes.

Stopping immunosuppressive treatment in autoimmune hepatitis (AIH): Is it justified (and in whom and when)?

BACKGROUND

Initial treatment of autoimmune hepatitis (AIH) with prednisolone ± azathioprine is based on randomised controlled trials. Many patients receive long-term immunosuppressive treatment to prevent disease relapse; this strategy has a weaker evidence base.

AIM

To consider whether immunosuppressive treatment (IST) withdrawal in AIH is justified and to develop a rationale for patient selection.

METHODS

We reviewed published papers between 1972 and 2018, which addressed the outcomes of IST withdrawal and/or complications of IST in AIH.

RESULTS

(1) AIH relapse rates after withdrawal of IST vary between 25% and 100%. There is heterogeneity in these studies regarding relapse definition, IST duration prior to withdrawal and criteria for biochemical and histological remission prior to withdrawal. (2) Factors associated with relapse following IST withdrawal include: (a) absence of an identifiable initial disease trigger, (b) presence of other autoimmune diseases, (c) longer time to biochemical remission and (d) elevated serum transaminases on treatment withdrawal. Reports of associations between relapse and age, IST duration and failure of histological remission have been inconsistent. (3) Continued IST reduces risk of AIH relapse over at least 5 years. However, there is no evidence that routine (as opposed to selective) long-term IST improves disease outcome. (4) Patients with AIH have an increased risk of extrahepatic cancer, notably non-melanoma skin cancer, to which long-term IST may contribute. Long-term corticosteroid therapy is associated with weight gain, low-trauma fractures, diabetes and possibly vascular disease.

CONCLUSIONS

While further studies are needed, evidence supports a strategy of IST withdrawal in some patients with AIH who have achieved remission.

Hellenic Association for the Study of the Liver Clinical Practice Guidelines: Autoimmune hepatitis

Autoimmune hepatitis (AIH) is a relatively rare acute or chronic liver disease of unknown etiology characterized by large heterogeneity. Its distribution is global, covering all ages, both sexes and all ethnic groups. The aim of the present Clinical Practice Guidelines (CPG) of the Hellenic Association for the Study of the Liver was to provide updated guidance and help to gastroenterologists, hepatologists, internists and general practitioners for AIH diagnosis and management. AIH diagnosis is based on clinicopathological characteristics: namely, polyclonal hypergammaglobulinemia, particularly of immunoglobulin G (IgG), circulating autoantibodies, interface hepatitis on liver histology, absence of viral hepatitis, and a favorable response to immunosuppression. Clinical manifestations at disease onset are variable, ranging from asymptomatic to the acute/severe form. Aminotransferase and bilirubin levels vary, while the presence of hepatitis at the histological level is a prerequisite for diagnosis. Autoantibodies are the hallmark for AIH diagnosis; therefore, the CPG describe the appropriate serological algorithm for their detection. AIH therapy should aim to achieve complete biochemical (normalization of IgG and aminotransferases) and histological remission. All patients who have active disease, even those with cirrhosis, should be treated with individualized and response-guided induction therapy using prednisolone in combination with azathioprine or mycophenolate mofetil as first-line therapy. Immunosuppression should be given for at least 3 years and for at least 2 years after the achievement of complete biochemical response, while a liver biopsy should be recommended before treatment discontinuation. Current CPG are also provided for several specific conditions and difficult-to-treat patients.

Lower 6-MMP/6-TG Ratio May Be a Therapeutic Target in Pediatric Autoimmune Hepatitis

BACKGROUND

Azathioprine (AZA) is the mainstay of maintenance therapy in pediatric autoimmune hepatitis (AIH). The use of thiopurines metabolites to individualize therapy and avoid toxicity has not, however, been clearly defined.

METHODS

Retrospective analysis of children ≤18 years diagnosed with AIH between January 2001 and 2016. Standard definitions were used for treatment response and disease flare. Thiopurine metabolite levels were correlated with the corresponding liver function test.

RESULTS

A total of 56 children (32 girls) were diagnosed with AIH at a median age of 11 years (interquartile range [IQR] 9). No difference in 6-thioguanine-nucleotide (6-TG) levels (271[IQR 251] pmol/8 × 10 red blood cell vs 224 [IQR 147] pmol/8 × 10 red blood cell, P = 0.06) was observed in children in remission when compared with those who were not in remission. No correlation was observed between the 6-TG and alanine aminotransferase levels (r = -0.179, P = 0.109) or between 6-methyl-mercaptopurine (6-MMP) and alanine aminotransferase levels (r = 0.139, P = 0.213). The 6-MMP/6-TG ratio was significantly lower in patients who were in remission (2[7] vs 5 (10), P = 0.04). Using a quartile analysis, we found that having a ratio of <4 was significantly associated with being in remission with OR 2.50 (95% confidence interval 1.02-6.10), P = 0.047. Use of allopurinol with low-dose AZA in 6 children with preferential 6-MMP production brought about remission in 5/6 (83.3%).

CONCLUSIONS

Thiopurine metabolite levels should be measured in patients with AIH who have experienced a loss of remission. A 6-MMP/6-TG ratio of <4 with the addition of allopurinol could be considered in these patients.

Autoimmune Hepatitis in the Elderly: Diagnosis and Pharmacologic Management

Autoimmune hepatitis (AIH) may present as acute or chronic hepatitis in the elderly. Advanced hepatic fibrosis and cirrhosis are common on first presentation in this population. In this review, we discuss the presentation, approach to diagnosis and management of AIH in the elderly. As polypharmacy is common in the elderly, careful medication use history is essential for detecting drug-induced AIH-like hepatitis. Steroid-sparing or minimizing therapeutic regimens are preferred to treat AIH in the elderly. For the purpose of induction, budesonide or lower dose prednisone in combination with azathioprine (AZA) regimens are preferred over high-dose prednisone monotherapy due to the higher risk of side effects of the later in the elderly. The goal of maintenance therapy should be to achieve full biochemical and histologic remission. Bone density monitoring and interventions to prevent steroid-related bone disease should be implemented throughout the course of the disease. Liver transplantation should be considered in the elderly patient with liver failure or early hepatocellular carcinoma if there are no significant comorbidities or compromise in functional status.

Autoimmune hepatitis: Standard treatment and systematic review of alternative treatments

Autoimmune hepatitis is a rare chronic inflammatory liver disease, affecting all ages, characterised by elevated transaminase and immunoglobulin G levels, positive autoantibodies, interface hepatitis at liver histology and good response to immunosuppressive treatment. If untreated, it has a poor prognosis. The aim of this review is to summarize the evidence for standard treatment and to provide a systematic review on alternative treatments for adults and children. Standard treatment is based on steroids and azathioprine, and leads to disease remission in 80%-90% of patients. Alternative first line treatment has been attempted with budesonide or cyclosporine, but their superiority compared to standard treatment remains to be demonstrated. Second-line treatments are needed for patients not responding or intolerant to standard treatment. No randomized controlled trials have been performed for second-line options. Mycophenolate mofetil is the most widely used second-line drug, and has good efficacy particularly for patients intolerant to azathioprine, but has the major disadvantage of being teratogenic. Only few and heterogeneous data on cyclosporine, tacrolimus, everolimus and sirolimus are available. More recently, experience with the anti-tumour necrosis factor-alpha infliximab and the anti-CD20 rituximab has been published, with ambivalent results; these agents may have severe side-effects and their use should be restricted to specialized centres. Clinical trials with new therapeutic options are ongoing.

The use of immunosuppression in autoimmune hepatitis: A current literature review

Autoimmune hepatitis (AIH) is an organ specific autoimmune condition which can manifest at any age of life. The heterogeneous nature of this condition means that great variation can be seen in severity, progression of disease and response to treatment within this patient group. Since the 1980s prednisolone and azathioprine have been used for induction and remission of the disease and remain the mainstay of treatment. Other immunosuppressive agents have been employed in difficult to treat cases. While there is less published data regarding these agents compared with the conventional treatments of steroid and azathioprine, there is mounting evidence to support the use of mycophenolate mofetil as a second-line agent. The calcineurin inhibitors, though less studied, additionally show promise. More data is needed on the use of biological agents in refractory disease. This review focuses on our centre’s approach to treatment of AIH in the context of a contemporary review of the literature.

Mycophenolate mofetil as an alternative treatment for autoimmune hepatitis

Autoimmune hepatitis (AIH) is an immune-mediated chronic liver disease characterized by hepatocellular inflammation, necrosis, and fibrosis, which can progress to cirrhosis and fulminant hepatic failure. The standard treatment for AIH includes corticosteroids alone or in combination with azathioprine. Although most patients achieve remission using the standard regimen, some patients do not respond due to either drug intolerance or refractory disease; in such cases alternative immunosuppressive agents should be explored. The second-line therapies are cyclophilin inhibitors such as cyclosporine A or tacrolimus, and nowadays mycophenolate mofetil (MMF) is widely used if azathioprine-based therapies are not tolerated. Although these are recommended as an alternative to the first-line regimen, there is insufficient evidence for the efficacy of second-line therapies, with the evidence based mainly on expert opinion. Therefore, we report an AIH patient receiving the standard regimen in whom remission did not occur due to side effects to azathioprine, but was successfully treated with MMF in combination with corticosteroids as an alternative to the standard regimen.

Efficacy of 6-Mercaptopurine as Second-Line Treatment for Patients With Autoimmune Hepatitis and Azathioprine Intolerance

BACKGROUND & AIMS

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that requires long-term immunosuppressive therapy. Although most patients have an excellent response to standard therapy (azathioprine in combination with corticosteroids), approximately 10%-15% have intolerance or an insufficient response to azathioprine treatment. We investigated whether 6-mercaptopurine (6-MP) is an effective second-line therapy for patients with AIH.

METHODS

We performed a retrospective study of 22 patients with AIH who were switched to 6-MP therapy after treatment with the combination of azathioprine and prednisolone at 2 tertiary care institutions in Europe (Germany and the United Kingdom) before November 15, 2014. We performed statistical analyses of data on clinical and biochemical responses collected 4 weeks after 6-MP treatment and then at regular physician visits.

RESULTS

A total of 15 of 20 patients with prior azathioprine intolerance (75%) responded to 6-MP treatment; 8 of these patients had a complete response and 7 had partial remission, based on biochemical features. In these 15 patients, 6-MP was well tolerated, whereas the 5 remaining patients had to be switched to different immunosuppressive regimes because of 6-MP intolerance. The 2 patients with insufficient response to azathioprine treatment also showed no response to 6-MP.

CONCLUSIONS

In patients with AIH and azathioprine intolerance, 6-MP seems to be an effective and well-tolerated second-line treatment. 6-MP might be ineffective in patients with insufficient response to azathioprine.

Role of mycophenolate mofetil for the treatment of autoimmune hepatitis-an observational study

BACKGROUND

Eighty percent (80%) of patients with Autoimmune hepatitis (AIH) respond to a combination of prednisolone and Azathioprine (AZA). Choice of treatment is limited for those who do not respond to this standard therapy. We evaluated the role of Mycophenolate mofetil (MMF) as a second line therapy in AIH.

METHOD

A retrospective observational study was carried out on all patients who received MMF for AIH.

RESULTS

Twenty out of 117 patients with AIH received MMF due to AZA intolerance (18 patients) or refractory disease (2 patients). Median age of the study patients was 56 (18-79) years, Male, n = 3 (15%) and Female, n = 18 (85%). After a median follow-up period of 47 (5-83) months, 14 (73.6%) patients were still on MMF with biochemical remission, including 4 out of 5 patients with cirrhosis. One patient was lost to follow-up. Three patients were intolerant of MMF due to adverse events, and two had disease refractory to MMF. Both these patients with refractory disease to MMF were initially unresponsive to AZA therapy.

CONCLUSION

MMF is a safe second line agent in patients with autoimmune hepatitis including those with cirrhosis.

Current and prospective pharmacotherapy for autoimmune hepatitis

INTRODUCTION

Corticosteroids alone or in combination with azathioprine are the mainstay therapies of autoimmune hepatitis. Suboptimal responses (treatment failure, partial response, drug toxicity), frequent relapse after drug withdrawal, and the emergence of alternative immunosuppressive medications have fueled the pursuit of new treatments. The goals of this review are to present current management strategies and evolving interventions.

AREAS COVERED

PubMed searches from 1970 - 2014 provide the bases for this review. Corticosteroid regimens should be administered until resolution of symptoms, laboratory tests, and liver tissue abnormalities. Treatment failure warrants high doses of the original regimen, and relapse warrants re-treatment followed by long-term maintenance with azathioprine. The calcineurin inhibitors, budesonide, and mycophenolate mofetil are evolving as frontline therapies, and they may be considered as salvage therapies with the exception of budesonide. Rapamycin, rituximab, and infliximab have also rescued refractory patients but experiences are limited. Anti-oxidants, recombinant molecules, mAbs, and modulators of critical cell populations are key prospects.

EXPERT OPINION

Autoimmune hepatitis must be managed by multiple medications that supplement or supplant current regimens depending on the clinical situation. Rescue therapies will emerge as adjunctive interventions to minimize tissue damage (prevent fibrosis and hepatocyte apoptosis) and improve immune tolerance (regulatory T cell manipulations).

Thiopurine metabolite measurement leads to changes in management of inflammatory bowel disease

BACKGROUND

The thiopurines azathioprine and 6-mercaptopurine are recommended for maintenance of remission in inflammatory bowel disease (IBD). Measurement of concentrations of the metabolites 6-thioguanine nucleotide and 6-methylmercaptopurine helps delineate interindividual variation in metabolism that may underlie variability in efficacy and toxicity.

AIMS

We aimed to perform a retrospective observational study to determine the utility of thiopurine metabolite testing following its introduction into South Australia.

METHODS

All patients having thiopurine metabolite tests done at Flinders Medical Centre between November 2008 and January 2010 were identified. Case notes of patients with testing done in the context of treatment for IBD were interrogated to determine the reason for testing, clinical context and outcome.

RESULTS

One hundred and fifty-one patients were identified with thiopurine metabolite testing for IBD with 157 testing episodes. Eighty (51.0%) had testing done for flare or inefficacy, 18 (11.5%) for adverse effects, 5 (3.2%) for a combination of inefficacy and adverse effects, and 54 (34.4%) for routine or other reasons. Testing was followed by improved outcomes of increased efficacy, reduced toxicity or change to alternative therapy in 55.0% of the inefficacy/flare group, 27.8% of the suspected adverse reaction group, 60.0% of the combination group, and 13.0% of the routine/other group. Allopurinol was used as cotherapy in 16 patients and led to marked improvements in metabolite concentrations.

CONCLUSIONS

Thiopurine metabolite testing has quickly become established in South Australia. When used for inefficacy or adverse effects, it often leads to improved outcomes. Prospective studies are needed to determine whether routine testing to guide dosing is of benefit.

A trial of mercaptopurine is a safe strategy in patients with inflammatory bowel disease intolerant to azathioprine: an observational study, systematic review and meta-analysis

BACKGROUND

Thiopurines maintain remission and modify disease course in inflammatory bowel disease. Use is limited by intolerance and subsequent drug withdrawal in approximately 17% of patients treated with azathioprine. Previous case series have addressed the success rates of re-treatment with mercaptopurine in these individuals.

AIMS

To determine the rate of tolerance when trialling mercaptopurine in azathioprine-intolerant patients and the factors predictive of success, and to perform a systematic review and meta-analysis of these data with other published data sets.

METHODS

A retrospective observational study of 149 patients with IBD (82 with Crohn's disease and 67 with ulcerative colitis) previously intolerant of azathioprine subsequently treated with mercaptopurine was performed. A meta-analysis was undertaken of all published studies of mercaptopurine use in azathioprine-intolerant patients (455 patients in 11 included studies).

RESULTS

Mercaptopurine was tolerated by 58% of azathioprine-intolerant patients in the Edinburgh cohort. In the meta-analysis, 68% tolerated mercaptopurine. A higher proportion of those in the meta-analysis with GI toxicity (62%) or hepatotoxicity (81%) were able to tolerate mercaptopurine than those with flu-like illness (36%). Among those patients who ceased mercaptopurine for further adverse effects, 59% experienced the same adverse effect as they had with azathioprine.

CONCLUSIONS

This meta-analysis shows that switching to mercaptopurine is a safe therapeutic strategy for over two-thirds of azathioprine-intolerant patients and may help optimise immunomodulatory therapy in inflammatory bowel disease. A trial of mercaptopurine should be attempted in IBD patients (except those with acute pancreatitis or bone marrow aplasia) before considering thiopurine intolerance.

Current concepts in the diagnosis and management of autoimmune hepatitis

Autoimmune hepatitis (AIH) is a progressive necroinflammatory liver disease associated with significant morbidity and mortality. Mainly affecting females, AIH has a varied clinical presentation from minor symptomatology to acute liver failure. The diagnosis should be considered in anyone with abnormal liver function tests. Diagnostic features include biochemical evidence of transaminitis, elevated IgG and positive autoantibodies. Liver biopsy may show interface hepatitis with portal-based plasma cell infiltrates. A clinical and pathological spectrum of disease exists with other autoimmune liver disease in rare cases. AIH responds promptly to immunosuppression therapy, including corticosteroids (prednis(ol)one or budesonide) with azathioprine. Treatment failure can be addressed with several second-line immunosuppressive agents. Liver transplantation remains a successful salvage therapy for acute autoimmune liver failure or treatment failure in chronic AIH complicated by synthetic dysfunction, portal hypertension or hepatocellular carcinoma.

Clinical significance of azathioprine metabolites for the maintenance of remission in autoimmune hepatitis

Azathioprine (AZA) is used to maintain remission in autoimmune hepatitis (AIH), but up to 18% of patients are unresponsive. AZA is a prodrug, and the formation of active thioguanine nucleotide (TGN) metabolites varies widely. We aimed to assess the relationship between AZA metabolite concentrations (i.e., TGNs and methylmercaptopurine nucleotides [MeMPNs]), thiopurine methyltransferase (TPMT) activity, therapeutic response, and toxicity in adult patients with AIH prescribed a stable dose of AZA for the maintenance of remission. Red blood cell (RBC) TGNs and MeMPNs were measured in serial blood samples over a 2-year period. The average TGNs (avTGNs) and MeMPNs (avMeMPNs) concentrations for each patient were used for analysis. Therapeutic response was defined as the ability to maintain remission, defined as a normal serum alanine aminotransferase (ALT) level (ALT <33 IU/mL). Patients who maintained remission (n = 53), compared to those who did not (n = 17), tended to be on lower doses of AZA (1.7 versus 2.0 mg/kg/day; P = 0.08), but had significantly higher concentrations of avTGN (237 versus 177 pmol/8 × 10(8) RBCs; P = 0.025). There was no difference in MeMPN concentrations or TPMT activities between the two groups. There was a negative correlation between ALT and avTGN (r(s) = -0.32; P = 0.007). An avTGN concentration of >220 pmol/8 × 10(8) RBCs best predicted remission, with an odds ratio of 7.7 (P = 0.003). There was no association between TGN, MeMPN, or TPMT activity and the development of leucopenia. Two patients developed AZA-induced cholestasis and the avMeMPN concentration was higher in those patients, compared to those who did not (14,277 versus 1,416 pmol/8 × 10(8) RBCs).

CONCLUSION

TGN concentrations of >220 pmol/8 × 10(8) RBCs are associated with remission. TGN measurement may help identify inadequate immunosupression. AZA-induced cholestasis was associated with increased MeMPN concentrations.

Diagnosis and treatment of autoimmune hepatitis

Autoimmune hepatitis is a chronic liver disease characterized by elevated aminotransferase levels, autoantibodies, increased γ-globulin or IgG levels and biopsy evidence of interface hepatitis. Recent advances include new practice guidelines that redefine criteria for remission to require complete biochemical and histological normalization on therapy; comparisons between the revised original and simplified diagnostic scoring systems; refined characterization of autoantibodies and their diagnostic performance parameters; proof of the safety and efficacy of combination budesonide and azathioprine therapy for non-cirrhotic patients; scrutiny of overlap syndromes; further analyses of the outcomes of orthotopic liver transplantation and the diagnosis and treatment of recurrent and de novo autoimmune hepatitis after transplantation. Anticipated consequences of the application of the new definition of therapeutic remission include a reduction in the proportion of patients achieving remission with conventional immunosuppression regimens and a corresponding increase in the need for alternative therapies.

Autoimmune hepatitis: current challenges in diagnosis and management in a chronic progressive liver disease

PURPOSE OF REVIEW

The understanding of autoimmune hepatitis (AIH) has evolved in the past two decades since diagnostic criteria were developed. Now with long-term experience with well characterized cohorts, strides have been gained in understanding the true epidemiology and natural history of the disease. Therapeutic trials have also added new tools to the armamentarium in managing this challenging disease.

RECENT FINDINGS

AIH has been demonstrated to be a disease of middle-aged women, with a disease course that frequently progresses to cirrhosis, transplant or death. Despite its rare prevalence, AIH is one of the most common indications for transplantation. Diagnosis remains challenging, and the most recently adopted criteria prove very specific but lack sensitivity in the diagnosis of AIH, particularly when presenting atypically. Recently, drug-induced AIH and IgG4-associated AIH have been proposed as distinct clinicopathological entities. Clinical trials for alternate therapeutics have long been needed, and recently two agents, budesonide and mycophenolate mofeteil, show promise in treating AIH.

SUMMARY

Increasing evidence has mounted to suggest that AIH is a disease that often requires long-term treatment, and frequently progresses to end-stage liver disease. Further research identifying predictors of poor outcome, optimal therapeutic regimens and duration of treatment is much needed.

Management of autoimmune hepatitis

PURPOSE OF REVIEW

Autoimmune hepatitis (AIH) is a chronic, progressive hepatitis of uncertain cause which has fluctuating activity characterized by periods of flares and remissions. Initial placebo-controlled trials carried out in the 1970s demonstrated that immunosuppression with steroids was extremely effective in reducing flares and progression of disease. The late 1980s-1990s could be described as the 'Dark Ages' of AIH treatment research. Very few clinical studies were performed during this time, although it became increasingly apparent that not all patients tolerated or responded to traditional immunosuppression, and that not all patients were easy to diagnose because of overlapping features with other autoimmune conditions. Fortunately, clinical research in the treatment of AIH has experienced a renaissance in the 21st century.

RECENT FINDINGS

This review highlights some of the more important recent discoveries, including the creation of the clinically useful short form of the autoimmune hepatitis diagnostic scoring system; accumulation of data supporting the use of mycophenolate and tacrolimus as second-line treatment; and the recent completion of the largest, double-blind, placebo-controlled trial of AIH treatment to date, comparing budesonide to prednisone.

SUMMARY

These new findings are pertinent to the everyday clinical management of patients with AIH.

Treatment of autoimmune hepatitis: a review of current and evolving therapies

Autoimmune hepatitis (AIH) is an immune-mediated necroinflammatory condition of the liver. Presentation can vary from the asymptomatic individual with abnormal liver function test to fulminant liver failure. The diagnosis is based on the combination of biochemical, autoimmune, and histological parameters, and exclusion of other liver diseases. Standard therapy consists of a combination of corticosteroids and azathioprine, which is efficacious in 80% of patients. Alternative therapies are increasingly being explored in patients who do not respond to the standard treatment and/or have unacceptable adverse effects. This review examines the role of alternative drugs (second-line agents) available for AIH treatment non-responders. These agents include budesonide, mycophenolate mofetil, cyclosporin, tacrolimus, 6-mercaptopurine, 6-thioguanine, rituximab, ursodeoxycholic acid, rapamycin, and methotrexate. In addition, the risk of opportunistic infections and malignancies are discussed. A treatment algorithm is proposed for the management of patients with AIH treatment non-responders.

Azathioprine metabolite measurements are not useful in following treatment of autoimmune hepatitis in Alaska Native and other non-Caucasian people

BACKGROUND

In autoimmune hepatitis (AIH) patients treated with azathioprine, the utility of measuring thiopurine methyltransferase (TPMT) and azathioprine metabolites has been limited.

OBJECTIVE

To evaluate the association between TPMT genotype and enzyme activity, and the impact of TPMT enzyme activity on levels of azathioprine metabolites and leukopenia to assess the clinical utility of monitoring azathioprine metabolites in Alaska Native and other non-Caucasian AIH patients.

METHODS

Individuals with AIH were recruited at the Alaska Native Medical Center (Alaska, USA) and the University of Texas Southwestern Medical Center (Texas, USA). Identification of TPMT genotype and measurement of enzyme activity were performed. The metabolites 6-thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine (6-MMP) were measured in participants who were on azathioprine, and the associations with disease remission and leukopenia were assessed.

RESULTS

Seventy-one patients with AIH were included. The distribution of TPMT genotypes was similar to that reported in other populationbased studies. TPMT genotype and phenotype were strongly associated (P<0.0001). Levels of 6-TGN and 6-MMP correlated with azathioprine dose only in individuals with normal TPMT enzyme activity. Patients with leukopenia due to azathioprine were no more likely to have abnormal TPMT enzyme levels than those without leukopenia (P=1.0). No specific level of 6-TGN metabolites was associated with remission or leukopenia.

DISCUSSION

Results of the present study were consistent with previous studies in Caucasian populations. TPMT genotype and phenotype correlated well, and levels of 6-TGN and 6-MMP metabolites were not associated with remission of AIH or toxicity of azathioprine.

CONCLUSIONS

The present study confirmed the limited utility of monitoring levels of azathioprine metabolites in AIH patients.