Use of thiopurines in inflammatory bowel disease

Thiopurines Maintenance Therapy in Children With Ulcerative Colitis: A Multicenter Retrospective Study

BACKGROUND AND AIMS

Thiopurines are an established treatment for pediatric ulcerative colitis (UC). However, data regarding safety and efficacy are lacking. We aimed to determine short and long-term outcome following thiopurines use in children with UC.

METHODS

We conducted a retrospective review of children (2-18 years) with UC treated with thiopurines between January 2008 and January 2019 at 7 medical centers in Israel. The primary outcome was corticosteroid (CS)-free clinical remission at week 52 following thiopurines initiation without the need for rescue therapy (infliximab, calcineurin inhibitors, or colectomy).

RESULTS

A total of 133 children were included [median age at diagnosis of 12.4 (interquartile range 11.0-15.8) years, 30 (23%) left-sided colitis, 113 (85%) with moderate or severe disease at diagnosis]. At diagnosis 58 patients (44%) were treated with 5-aminosalicylates and 72 (54%) with CS. Sixty patients (45%) received thiopurines as 1st line maintenance therapy. Seventy-four patients (56%) had CS-free clinical remission at week 52 without rescue therapy. Predictors of clinical remission were not identified. In a sub-analysis among patients with steroid-responsive moderate to severe UC, 59 (55%) patients achieved this outcome. The likelihood of remaining free of rescue therapy among thiopurines-treated patients was 83%, 62%, 45%, and 37% at 1, 2, 3, and 4 years, respectively.

CONCLUSION

More than half of children with UC starting thiopurines without previous or concomitant biologic therapy have CS-free clinical remission at 52 weeks later without the need for rescue therapy. Thiopurines are effective in pediatric UC and could be considered prior to biologics.

Inflammatory factors, genetic variants, and predisposition for preterm birth

Preterm birth is a major clinical and public health challenge, with a prevalence of 11% worldwide. It is the leading cause of death in children younger than 5 years old and represents 70% of neonatal deaths and 75% of neonatal morbidity. Despite the clinical and public health significance, this condition's etiology is still unclear, and most of the cases are spontaneous. There are several known preterm birth risk factors, including inflammatory diseases and the genetic background, although the underlying molecular mechanisms are far from understood. The present review highlights the research advances on the association between inflammatory-related genes and the increased risk for preterm delivery. The most associated genetic variants are the TNFα rs1800629, the IL1α rs17561, and the IL1RN rs2234663. Moreover, many of the genes discussed in this review are also implicated in pathologies involving inflammatory or autoimmune systems, such as periodontal disease, bowel inflammatory disease, and autoimmune rheumatic diseases. This review presents evidence suggesting a common genetic background to preterm birth, autoimmune and inflammatory diseases susceptibility.

Inflammatory bowel disease: Therapeutic limitations and prospective of the stem cell therapy

Inflammatory bowel disease (IBD), consisting primarily of ulcerative colitis and Crohn’s disease, is a group of debilitating auto-immune disorders, which also increases the risk of colitis-associated cancer. However, due to the chronic nature of the disease and inconsistent treatment outcomes of current anti-IBD drugs (e.g., approximately 30% non-responders to anti-TNFα agents), and related serious side effects, about half of all IBD patients (in millions) turn to alternative treatment options. In this regard, mucosal healing is gaining acceptance as a measure of disease activity in IBD patients as recent studies have correlated the success of mucosal healing with improved prognosis. However, despite the increasing clinical realization of the significance of the concept of mucosal healing, its regulation and means of therapeutic targeting remain largely unclear. Here, stem-cell therapy, which uses hematopoietic stem cells or mesenchymal stem cells, remains a promising option. Stem cells are the pluripotent cells with ability to differentiate into the epithelial and/or immune-modulatory cells. The over-reaching concept is that the stem cells can migrate to the damaged areas of the intestine to provide curative help in the mucosal healing process. Moreover, by differentiating into the mature intestinal epithelial cells, the stem cells also help in restoring the barrier integrity of the intestinal lining and hence prevent the immunomodulatory induction, the root cause of the IBD. In this article, we elaborate upon the current status of the clinical management of IBD and potential role of the stem cell therapy in improving IBD therapy and patient’s quality of life.

Thiopurines in Pediatric Inflammatory Bowel Disease: Current and Future Place

Thiopurines have been widely used to maintain steroid-free remission in children with inflammatory bowel disease (IBD). However, within the expanding treatment armamentarium, the role of these non-selective immunomodulators has been questioned, especially in pediatric patients, who often present with a more aggressive disease course, which can impact growth and development. The less favorable safety but also inferior efficacy profile associated with thiopurines, in contrast to the newer biological therapies, has interfered with their use. The future place of thiopurines in the management of childhood IBD, therefore, needs revisiting. This review provides a practical overview on the historical and current use of thiopurines in pediatric IBD with specific attention for thiopurine S-methyltransferase testing and monitoring of thiopurine metabolite levels as an approach to improve outcomes. We also give a personal expert opinion on the future role of these drugs in childhood IBD.

Thiopurine S-methyltransferase genetic polymorphisms in adult patients with inflammatory bowel diseases in the Latvian population

BACKGROUND

Thiopurine methyltransferase (TPMT) plays a significant role in the metabolism of thiopurines, and, for patients with inflammatory bowel disease (IBD), it is useful to perform TPMT genotyping prior to azathioprine (AZA) treatment. In this study, we determined TPMT gene polymorphisms in a cohort of IBD patients in Latvia.

METHODS

DNA samples were obtained from 244 IBD patients, and qPCR was performed for detection of rs1800462, rs1800460, and rs1142345 single-nucleotide polymorphisms (SNPs). Three common, non-functional TPMT alleles (TPMT*2, *3B, and *3C) were identified (women, 51%; men, 49%). TPMT*2, *3A, *3B, and *3C allelic variants detected using qPCR were consistent with restriction fragment length polymorphism (RFLP) data.

RESULTS

Among patients, 78% had ulcerative colitis and 22% had Crohn's disease, with 93.9% of the former carrying a wild-type homozygous TPMT*1/*1 genotype and 6.1% carrying heterozygous genotypes. The most frequent polymorphisms were TPMT*1/*3A (5.3%: two variants: TPMT*3B and TPMT*3C), TPMT*1/*3C (0.4%), and TPMT*1/*2 (0.4%). None of the patients carried a TPMT*3B polymorphism and no patients were homozygous for any mutation.

CONCLUSION

This is the first study to identify TPMT gene polymorphisms in adult IBD patients in Latvia. The results indicate that the frequency of common TPMT alleles is similar to that of other European populations.

The continuous rediscovery and the benefit-risk ratio of thioguanine, a comprehensive review

Introduction: In the 1950s, thioguanine (TG), a thiopurine-derivative together with azathioprine (AZA) and mercaptopurine (MP), were developed for the treatment of childhood leukemia. Over the years, the use of TG was also explored for other, mainly immune-mediated and inflammatory, diseases such as in the field of dermatology and rheumatology (e.g. psoriasis, systemic lupus erythematosus (SLE)) and gastroenterology and hepatology (e.g. inflammatory bowel diseases (IBD), autoimmune hepatitis).Areas covered: This review provides a comprehensive overview of all the clinical uses of TG and describes its mechanism of action, pharmacokinetic/pharmacodynamic features, and toxicity.Expert opinion: Thioguanine has shown beneficial clinical effects in hematological (particularly leukemia) and several immune-inflammatory diseases including psoriasis, SLE, polycythemia vera, Churg-Strauss syndrome, IBD, collagenous sprue, refractory celiac disease, and autoimmune hepatitis. Thioguanine is not effective in treating solid-cancers. At relatively low dosages, i.e. 0.2- 0.3mg/kg/day or 20 mg/day, TG has a favorable risk-benefit ratio and is a safe and effective drug in the long-term treatment of amongst other IBD patients. Thioguanine toxicity, especially myelotoxicity, and hepatotoxicity, including nodular regenerative hyperplasia (NRH) of the liver, is limited when dosed adequately. The occurrence of NRH appears dose-dependent and has been especially described during high dose TG above 40 mg/day.

Thiopurine Therapy in Patients With Inflammatory Bowel Disease: A Focus on Metabolism and Pharmacogenetics

Thiopurines have been widely used for the maintenance of remission or steroid sparing in patients with inflammatory bowel disease. However, potential drug-related adverse events frequently interfere with their use. Indeed, drug withdrawals associated with adverse reactions have been reported in approximately 25% of patients. To balance the efficacy, safety, and tolerability of thiopurines, regular monitoring of biomarkers (complete blood cell count, liver function test, and metabolic profiles), steady dose escalation, and pretreatment thiopurine S-methyltransferase (TPMT) genotype screening have been routinely recommended. However, the complex thiopurine metabolic pathway and individual differences attributed to pharmacogenetic diversity limit the effectiveness of these strategies in the optimization of thiopurine therapy. Recently, in an effort to facilitate more accurate and personalized prediction of thiopurine response or toxicity, novel genetic markers including NUDT15 and FTO genes were discovered. These discoveries are remarkable because TPMT screening has minimal efficacy for predicting myelosuppression especially in Asian populations, despite the fact that thee populations have a higher frequency of myelosuppression than Western populations. This review focuses on the current understanding of the metabolic pathway and the pharmacogenetics of thiopurines and suggests a personalized preventive strategy against potential adverse drug reactions to optimize their therapeutic application.

Pharmacological Autophagy Regulators as Therapeutic Agents for Inflammatory Bowel Diseases

The arsenal of effective molecules to treat patients with chronic inflammatory bowel diseases (IBDs) remains limited. These remitting-relapsing diseases have become a global health issue and new therapeutic strategies are eagerly awaited to regulate the course of these disorders. Since the association between autophagy-related gene polymorphism and an increased risk of Crohn's disease (CD) has been discovered, a new domain of investigation has emerged, focused on the intracellular degradation system, with the objective of generating new medicines that are safer and more targeted. This review summarizes the drugs administered to IBD patients and describes recently emerged therapeutic agents. We compile evidence on the contribution of autophagy to IBD pathogenesis, give an overview of pharmacological autophagy regulators in animal models of colitis, and propose novel therapeutic avenues based on autophagy components.

Anti-inflammatory bowel effect of industrial orange by-products in DSS-treated mice

Pectin, phenolic compounds and/or Maillard reaction products present in orange by-products may exert an anti-inflammatory bowel effect in DSS-treated mice.

Inflammatory Bowel Disease: Pathophysiology and Current Therapeutic Approaches

Inflammatory bowel diseases, most commonly categorized as Crohn's disease and ulcerative colitis, are immune mediated chronic inflammatory disorders of the gastrointestinal tract. The etiopathogenesis is multifactorial with different environmental, genetic, immune mediated, and gut microbial factors playing important role. The current goals of therapy are to improve clinical symptoms, control inflammation, prevent complications, and improve quality of life. Different therapeutic agents, with their indications, mechanisms of action, and side effects are discussed in this chapter. Anti-integrin therapy, a newer therapeutic class, with its potential beneficial role in both Crohn's disease and ulcerative colitis is also mentioned. In the end, therapeutic algorithms for both diseases are reviewed.

Preterm birth in women with inflammatory bowel disease - the association with disease activity and drug treatment

BACKGROUND

The inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC) have been associated with an increased risk of preterm birth.

MATERIAL AND METHODS

We identified all 246 singleton preterm births among women with IBD between July 2006 and December 2010 as cases and an equal number of controls with IBD from the Swedish national health registers, matched by maternal age, parity and IBD diagnosis (CD/UC). From register data and medical charts, we obtained information on reproductive history, comorbidity, disease activity and drug treatment (corticosteroids, 5-aminosalicylates, sulfasalazine, thiopurines and anti-TNF) as risk factors for preterm birth. Associations were estimated using conditional logistic regression and results were presented as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Previous preterm birth was more common among cases, OR 6.13 (95%CI: 2.51-15.01). Significant activity at any time during pregnancy (OR: 2.20; 95%CI: 1.37-3.53), and in particular both in early and in late pregnancy, was more common for cases (OR: 4.78 95%; CI: 2.10-10.9). The OR for immunosuppressive treatment with thiopurines or anti-TNF was 1.88 (1.04-3.39) without significant activity and 12.78 (95%CI: 3.68-44.72) with. The risk for women who discontinued thiopurines was 6.56 (1.44-29.82).

CONCLUSIONS

Significant activity and immunosuppressive treatment was associated with preterm birth, particularly in women with both. The existing recommendations to aim at maintaining quiescent disease during pregnancy, even if it means continuing immunosuppressive treatment, are rational.

How I treat my inflammatory bowel disease-patients with thiopurines?

Thiopurines are essential drugs to maintain remission in patients with inflammatory bowel disease (IBD). Thiopurines used in IBD are azathioprine (2.0-2.5 mg/kg), mercaptopurine (1.0-1.5 mg/kg) and thioguanine (0.2-0.3 mg/kg). However, mainly due to numerous adverse events associated with thiopurine use, almost 50% of the patients have to discontinue conventional thiopurine treatment. Extensive monitoring and the application of several treatment strategies, such as split-dose administration, co-administration with allopurinol or dose reduction/increase, may increase the chance of successful therapy. With this review, we provide practical information on how thiopurines are initiated and maintained in two thiopurine research centers in The Netherlands. We provide clinical information concerning safety issues, indications and management of therapy that may serve as a guide for the administration of thiopurines in IBD patients in daily practice.

The Impact of Azathioprine-Associated Lymphopenia on the Onset of Opportunistic Infections in Patients with Inflammatory Bowel Disease

Background

Thiopurines are known to cause lymphopenia (<1,500 lymphocytes/μl). As severe lymphopenia (<500C/μl) is associated with opportunistic infections, we investigated severity of thiopurine-related lymphopenia and development of opportunistic infections in our tertiary referral centre.

Methods

We retrospectively screened medical records of 1,070 IBD patients and identified 100 individuals that developed a total of 161 episodes of lymphopenia during thiopurine treatment between 2002 and 2014. Occurrence of opportunistic infections was documented. A control group consisted of IBD patients receiving thiopurines but without developing lymphopenia.

Results

Of a total of 161 episodes of lymphopenia, 23% were severe (<500C/μl). In this subgroup, thiopurine dosing was modified in 64% (dosage reduction: 32%, medication discontinued: 32%). We identified 9 cases (5.5%) of opportunistic infections, of which only two occurred during severe lymphopenia. One opportunistic infection (4.5%) was identified in the control group. No association was found between opportunistic infections and severity of lymphopenia. All patients who suffered from opportunistic infections were receiving additional immunosuppressive medication.

Conclusion

Our patients treated with thiopurines rarely developed severe lymphopenia and opportunistic infections did not occur more often than in the control group. A careful monitoring of lymphocytes and prophylactic adjustment of thiopurine therapy might contribute to this low incidence.

Probiotics and prebiotics in ulcerative colitis

The intestinal microbiota is one of the key players in the etiology of ulcerative colitis. Manipulation of this microflora with probiotics and prebiotics is an attractive strategy in the management of ulcerative colitis. Several intervention studies for both the induction and maintenance of remission in ulcerative colitis patients have been performed. Most of these studies evaluated VSL#3 or E. Coli Nissle 1917 and in general there is evidence for efficacy of these agents for induction and maintenance of remission. However, studies are frequently underpowered, lack a control group, and are very heterogeneous investigating different probiotic strains in different study populations. The absence of well-powered robust randomized placebo-controlled trials impedes the widespread use of probiotics and prebiotics in ulcerative colitis. However, given the promising results that are currently available, probiotics and prebiotics may find their way to the treatment algorithm for ulcerative colitis in the near future.

Nucleoside transporter proteins as biomarkers of drug responsiveness and drug targets

Nucleoside and nucleobase analogs are currently used in the treatment of solid tumors, lymphoproliferative diseases, viral infections such as hepatitis and AIDS, and some inflammatory diseases such as Crohn. Two gene families are implicated in the uptake of nucleosides and nucleoside analogs into cells, SCL28 and SLC29. The former encodes hCNT1, hCNT2, and hCNT3 proteins. They translocate nucleosides in a Na⁺ coupled manner with high affinity and some substrate selectivity, being hCNT1 and hCNT2 pyrimidine- and purine-preferring, respectively, and hCNT3 a broad selectivity transporter. SLC29 genes encode four members, being hENT1 and hENT2 the only two which are unequivocally implicated in the translocation of nucleosides and nucleobases (the latter mostly via hENT2) at the cell plasma membrane. Some nucleoside-derived drugs can also interact with and be translocated by members of the SLC22 gene family, particularly hOCT and hOAT proteins. Inter-individual differences in transporter function and perhaps, more importantly, altered expression associated with the disease itself might modulate the transporter profile of target cells, thereby determining drug bioavailability and action. Drug transporter pharmacology has been periodically reviewed. Thus, with this contribution we aim at providing a state-of-the-art overview of the clinical evidence generated so far supporting the concept that these membrane proteins can indeed be biomarkers suitable for diagnosis and/or prognosis. Last but not least, some of these transporter proteins can also be envisaged as drug targets, as long as they can show “transceptor” functions, in some cases related to their role as modulators of extracellular adenosine levels, thereby providing a functional link between P1 receptors and transporters.

Azathioprine does not reduce adenoma formation in a mouse model of sporadic intestinal tumorigenesis

AIM: To investigate if azathioprine could reduce adenoma formation in Apc^Min/+, a mouse model of sporadic intestinal tumorigenesis.

METHODS: Azathioprine was administered via drinking water (estimated 6-20 mg/kg body weight per day) to Apc^Min/+ and wildtype mice. Control animals received vehicle only (DMSO) dissolved in drinking water. At 15 wk of age all mice were sacrificed and intestines of Apc^Min/+ were harvested for evaluation of polyp number. Azathioprine induced toxicity was investigated by immunohistochemical analysis on spleens.

RESULTS: All azathioprine treated mice showed signs of drug-associated toxicity such as weight loss and development of splenic T-cell lymphomas. Although this suggests that the thiopurine concentration was clearly in the therapeutic range, it did not reduce tumor formation (48 ± 3.1 adenomas vs 59 ± 5.7 adenomas, P = 0.148).

CONCLUSION: We conclude that in the absence of inflammation, azathioprine does not affect intestinal tumorigenesis.

Allopurinol: a useful adjunct to thiopurine therapy for pediatric ulcerative colitis in the biologic era

Thiopurines are used as a maintenance therapy in patients with ulcerative colitis (UC). For some patients the metabolism of thiopurines is unfavorable, leading to increased adverse effects, including hepatotoxicity. There are many reports in the adult literature concerning the manipulation of thiopurine metabolism with allopurinol; however, there is only 1 publication in this respect for pediatric UC. We present 3 pediatric cases of UC wherein the combination of allopurinol and low-dose 6-mercaptopurine allowed for shunting of thiopurine metabolites to a more favorable pattern. This intervention supported clinical remission in all, including one case poorly responsive to infliximab.

Review article: permanent drug withdrawal is desirable and achievable for autoimmune hepatitis

BACKGROUND

Autoimmune hepatitis can be rendered treatment-free, but the difficulty, frequency and risks associated with the pursuit of this outcome are unclear.

AIM

To describe the frequency that autoimmune hepatitis can be rendered treatment-free, identify the features that characterise these patients, examine the pathogenic pathways that may sustain or terminate the disease and indicate management protocols that can obtain this result.

METHODS

Studies cited in Pub Med from 1972-2014 for autoimmune hepatitis, treatment, relapse, remission and outcome were selected.

RESULTS

The frequency of a treatment-free state varies from 19% to 40% in patients observed for ≥3 years after drug withdrawal. Complete laboratory resolution and reversion to normal liver tissue prior to drug withdrawal favours this response. The development of cirrhosis during therapy may increase treatment-dependence. Persistent liver damage and the generation of neo-antigens during the apoptosis of hepatocytes may perpetuate the disease. Genetic and age-related effects on the vigour of the immune response may also contribute. Reversion to normal liver tissue is achieved in only 22% of patients during conventional corticosteroid therapy, and the emerging pharmacological and biological interventions may improve this frequency. A management strategy designed to achieve a treatment-free state accommodates all candidates for this outcome, and it can be modified to a long-term maintenance strategy as warranted by the clinical response.

CONCLUSIONS

Permanent drug withdrawal is a treatment outcome that is desirable and achievable in patients with autoimmune hepatitis. Normalisation of liver tests and liver tissue during treatment enhances this occurrence.

IBD medications during pregnancy and lactation

IBD often affects patients during their peak reproductive years. Several drugs are available for the treatment of IBD and new drugs are continuously in the pipeline. As long-term administration of medications is often necessary, the safety of drug therapy during pregnancy and breast-feeding needs to be considered in daily clinical practice. The aim of this Review is to summarize the latest information concerning the safety of medications used to treat IBD during pregnancy and lactation, as well as their effect on fertility. Although only thalidomide and methotrexate are absolutely contraindicated during pregnancy and breast-feeding, alternatives to ciprofloxacin, natalizumab and sodium phosphate should also be considered for pregnant women. Breast-feeding is also discouraged while on treatment with ciclosporin, metronidazole and ciprofloxacin. However, therapy with 5-aminosalicylic acid preparations, glucocorticoids, thiopurines and TNF inhibitors are acceptable during pregnancy and lactation. Pregnant women who have symptomatic IBD or who require therapy should have the opportunity to discuss any associated risks to their pregnancy and infant with the appropriate consultants. By ensuring that the patient and her family are informed, the clinical outcome might be optimized.

Therapeutic drug monitoring in inflammatory bowel disease

Tumor necrosis factor (TNF)-α inhibitors and thiopurines are among the most important classes of medications utilized in the clinical management of Crohn's disease and ulcerative colitis. A significant proportion of patients loses response to these agents or develops adverse effects during the course of the treatment. Monitoring of drug levels and anti-drug antibodies (for TNF-α inhibitors) and metabolite levels (for thiopurines) can provide valuable insight into the possible etiology of unfavorable outcomes and allow for an appropriate management strategy for these patients. This review summarizes the current knowledge on the clinical implications of therapeutic drug monitoring in inflammatory bowel disease patients treated with TNF-α inhibitors and thiopurines.

Chronic pancreatitis as presentation of Crohn’s disease in a child

It is reported that a pancreatic disease may precede the diagnosis of inflammatory bowel disease (IBD) both in children and in adults. Idiopathic chronic pancreatitis, however, occasionally co-exists with the IBD, mainly at pediatric age. We report a case of a patient who progressively developed the features of a chronic pancreatitis, before the diagnosis of Crohn’s Disease (CD). Ten months after the onset of the first episode of pancreatitis the patient developed bloody diarrhea, mucus stools and biochemical findings of inflammation. The colonoscopy revealed a diffuse colitis without involvement of the last loop and the gastroscopy showed inflammation of the iuxta-papillary area. The histological findings confirmed the diagnosis of CD that involved the colon and the duodenum. In conclusion, in children the idiopathic chronic pancreatitis may be an unusual presentation of CD. Thus, if other known cause of chronic pancreatitis are not found, a not invasive work up to exclude the IBD should be warranted. An early coincidental diagnosis of the IBD may delay the progression of the pancreatic disease.

Risk of lymphoma after treatment of inflammatory bowel disease with azathioprine

Inflammatory bowel disease (IBD) is a chronic, non-specific inflammatory disease of the intestine, characterized by excessive activation of the immune system. Immunosuppressive therapy has been widely and effectively used in IBD patients. However, the occurrence of lymphoma after immunosuppressive therapy for IBD, especially azathioprine, has been recently reported. This article reviews the clinical application of azathioprine in IBD, the possible mechanisms responsible for lymphoma induction by azathioprine, and the assessment of benefit and risk of immunosuppressive therapy for IBD.

Liver abnormalities in bowel diseases

Liver abnormalities are often seen in bowel diseases. Whether these represent aspects of two separate diseases, or if one is causing the other, is not always easy to decide. Extraintestinal manifestations of inflammatory bowel disease (IBD) or coeliac disease are frequently observed. Of these extraintestinal manifestations, hepatic disorders are among the most common. Primary sclerosing cholangitis (PSC) and primary biliary cirrhosis are the most frequent hepatic disorders in IBD and coeliac disease, respectively. Genetic studies have lately elucidated the associations between IBD and PSC, but there is still a long way until we have complete understanding of the molecular aetiology and pathophysiology of these conditions. There is no curative treatment available for PSC, besides liver transplantation. Steatosis and cholelithiasis are also common in IBD, as are signs of hepatic injury due to IBD treatment. Less common liver abnormalities include liver abscesses, hepatic thromboembolic events, granulomatous liver disease and hepatic amyloidosis.