Azathioprine and anti-TNF alpha therapies in Crohn's disease: a review of pharmacology, clinical efficacy and safety

Secondary immunodeficiencies and infectious considerations of biologic immunomodulatory therapies

Biologic immunomodulatory medications have rapidly expanded in the previous decades, providing new treatment options for individuals with a spectrum of oncologic, allergic, rheumatologic, and neurologic conditions. Biologic therapies alter immune function and can impair key host defense mechanisms, resulting in secondary immunodeficiency and increased infectious risks. Biologic medications can increase general risk for upper respiratory tract infections but can also be associated with unique infectious risks owing to distinct mechanisms of action. With the widespread use of these medications, providers in every area of medicine will likely care for individuals receiving biologic therapies and understanding their potential infectious complications can help mitigate these risks. This practical review discusses the infectious implications of biologics by class of medication and provides recommendations regarding the examination and screening both before therapy initiation and while the patient is receiving the medication. With this knowledge and background, providers can reduce risk whereas patients receive the treatment benefits of these biologic medications.

Equivalent Cellular and Humoral Immunity to Varicella Zoster Virus in Patients With Inflammatory Bowel Disease and Healthy Older Adults for Whom Immunization Is Recommended

INTRODUCTION

Patients with inflammatory bowel disease (IBD) are at an increased risk of herpes zoster (HZ). HZ is caused by reactivation of the varicella zoster virus (VZV) and is prevented by strong VZV-specific cell-mediated immunity. The aim of our study was to evaluate whether patients with IBD had lower or equivalent protection compared with healthy controls (HCs) at age 50 years and older.

METHODS

We performed a cross-sectional study at a single academic center and evaluated cellular and humoral immunity to VZV in patients with IBD at age 35-49 years vs HCs aged 50-59 years. All patients with IBD were on stable medication regimens for at least 3 months. VZV-specific cell-mediated immunity was measured via ELISPOT, and humoral immunity was measured via a quantitative VZV antibody enzyme-linked immunosorbent assay assay.

RESULTS

Seventy-seven patients with IBD and 12 HCs were enrolled in the study. There was no significant difference in ELISPOT counts between patients with IBD and HCs (P = 0.54). In addition, there was also no significant difference between ELISPOT counts in immunosuppressed patients with IBD (N = 45) and HCs (P = 0.32). We also found no correlations between ELISPOT counts and age (Spearman rho 0.014; P = 0.90). Patients with IBD had similar IgG VZV antibody levels (median 19 mIU/mL; range 0.5-218) compared with HCs (median 23.5 mIU/mL (range 4-34); P = 0.54).

DISCUSSION

Young patients with IBD have equivalent cellular and humoral immunity to VZV as healthy older adults in whom HZ immunization is recommended.

[Recommendations when switching therapy from immunosuppressive drugs to dupilumab in patients with atopic dermatitis]

Basierend auf neuen Erkenntnissen zur molekularen Pathogenese der atopischen Dermatitis, wurde neben Glukokortikoiden und Ciclosporin mit Dupilumab nun auch eine zielgerichtete antientzündliche Systemtherapie zugelassen. Wegen ihrer Pharmakologie sind weder Glukokortikoide und Ciclosporin noch die außerhalb der Zulassung angewendeten Substanzen Methotrexat, Azathioprin und Mycophenolsäurederivate für eine Langzeittherapie geeignet. Bei der Umstellung der Therapie von den genannten niedermolekularen Substanzen auf Dupilumab sollten verschiedene Faktoren berücksichtigt werden. Hierbei sind sowohl der konkrete Anlass der Umstellung (Unwirksamkeit, unerwünschte Wirkungen oder sich einstellende Kontraindikationen) als auch die pharmakologischen Gegebenheiten zu berücksichtigen. Da es hierzu bisher keine konkreten klinischen Untersuchungen gibt, haben die Autoren auf der Grundlage einer Literaturrecherche Handlungsempfehlungen für den praktischen Alltag erarbeitet.

The Association Between Azathioprine Genetic Polymorphisms, Clinical Efficacy and Adverse Drug Reactions Among Egyptian Patients with Autoimmune Diseases

Purpose

The study aimed to detect the frequencies of allelic variants (TPMT*3A, TPMT*3C, and TPMT*3G) in the TPMT genes in the Egyptian population and assess the association between TPMT polymorphisms and azathioprine (AZA)—clinical efficacy and adverse drug reactions among Egyptian patients with autoimmune diseases.

Patients and Methods

Design

A prospective, observational single-center clinical trial.

Setting

Rheumatology and Rehabilitation Department, Kasr Alainy University Hospital, Faculty of Medicine, Cairo University.

Patients

Patients attending Kasr Alainy Rheumatology Outpatient Clinic between December 1, 2017 and June 30, 2019 were included in the study after signing a consent form. TPMT genetic polymorphisms were detected for all patients, and the association between polymorphisms presence and azathioprine’s clinical efficacy and adverse drug reactions were determined.

Results

A total of 150 patients with a mean age of 35.85 years were enrolled in this study. About 72% of patients were heterozygous in the TPMT*3 G460A and TPMT*3 A719G mutant alleles and 81% were wild type in the TPMT*2 G238C mutant allele. Abnormal liver function tests were detected in 42% of patients. Myelosuppression was presented as anemia which was detected in 63% of patients, leucopenia in 51%, and thrombocytopenia in 25% of patients. AZA clinical failure has occurred in 50% of patients where AZA was discontinued or shifted to another drug which occurred in 45% of patients. Myelosuppression rates were higher in homozygous patients in the three mutant alleles, but statistically significant in TPMT*2 G238C while not statistically significant in TPMT*3 G460A and TPMT*3 A719G. Females had a higher risk of immunosuppression than males (p-value 0.031).

Conclusion

The study provided an overview of the genomic variations in the Egyptian population. Routine TPMT genotyping prior to the initiation of AZA therapy should be considered.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Pharmacokinetics and Immune Reconstitution Following Discontinuation of Thiopurine Analogues: Implications for Drug Withdrawal Strategies

BACKGROUND AND AIMS

Discontinuation of thiopurine analogues is common prior to live vaccines, during infection or when de-escalating therapy. Data regarding clearance of active metabolites and immune re-constitution is scant. We aimed to determine drug elimination and immune re-constitution following thiopurine cessation.

METHODS

The elimination kinetics of 6-thioguanine nucleotides (6-TGN) were determined in nine inflammatory bowel disease [IBD] patients discontinuing thiopurines. Immune reconstitution was evaluated by toxic shock syndrome toxin 1 [TSST1] or anti-CD3 [OKT3]-induced CD4+ T-cell proliferation, following an initial exposure to TSST1 and 6-mercaptopurine [6MP], separately or combined.

RESULTS

All patients discontinuing thiopurines displayed first-order elimination kinetics of 6-TGN, with a median elimination half-life of 6.8 days [interquartile range 5.9-8.4]. Resting CD4+ T-cells exposed to 6MP preserved their response to subsequent polyclonal or Vβ2+-preferential stimulation. By contrast, exposure of TSST1-activated CD4+ T-cells to 6MP inhibited their subsequent Vβ2+clonal response to further stimulation [p = 0.008], whereas overall response to further non-Vβ2-selective stimulation with OKT3 was unaltered [p = 0.9].

CONCLUSIONS

Upon 6MP/azathioprine discontinuation, a 6-TGN elimination half-life of less than 10 days is expected in most patients. Immune reconstitution, however, may take longer for T-cell clones exposed to stimulation during thiopurine treatment. These findings may be useful when considering thiopurine cessation.

Plasma N-Glycan Signatures Are Associated With Features of Inflammatory Bowel Diseases

BACKGROUND & AIMS

Biomarkers are needed for early detection of Crohn's disease (CD) and ulcerative colitis (UC) or to predict patient outcomes. Glycosylation is a common and complex posttranslational modification of proteins that affects their structure and activity. We compared plasma N-glycosylation profiles between patients with CD or UC and healthy individuals (controls).

METHODS

We analyzed the total plasma N-glycomes of 2635 patients with inflammatory bowel diseases and 996 controls by mass spectrometry with a linkage-specific sialic acid derivatization technique. Plasma samples were acquired from 2 hospitals in Italy (discovery cohort, 1989 patients with inflammatory bowel disease [IBD] and 570 controls) and 1 medical center in the United States (validation cohort, 646 cases of IBD and 426 controls). Sixty-three glycoforms met our criteria for relative quantification and were extracted from the raw data with the software MassyTools. Common features shared by the glycan compositions were combined in 78 derived traits, including the number of antennae of complex-type glycans and levels of fucosylation, bisection, galactosylation, and sialylation. Associations of plasma N-glycomes with age, sex, CD, UC, and IBD-related parameters such as disease location, surgery and medication, level of C-reactive protein, and sedimentation rate were tested by linear and logistic regression.

RESULTS

Plasma samples from patients with IBD had a higher abundance of large-size glycans compared with controls, a decreased relative abundance of hybrid and high-mannose structures, lower fucosylation, lower galactosylation, and higher sialylation (α2,3- and α2,6-linked). We could discriminate plasma from patients with CD from that of patients with UC based on higher bisection, lower galactosylation, and higher sialylation (α2,3-linked). Glycosylation patterns were associated with disease location and progression, the need for a more potent medication, and surgery. These results were replicated in a large independent cohort.

CONCLUSIONS

We performed high-throughput analysis to compare total plasma N-glycomes of individuals with vs without IBD and to identify patterns associated with disease features and the need for treatment. These profiles might be used in diagnosis and for predicting patients' responses to treatment.

Risk of Lymphoma in Patients With Inflammatory Bowel Disease Treated With Anti-tumour Necrosis Factor Alpha Agents: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

The association between anti-tumour necrosis factor alpha agents and the risk of lymphoma in patients with inflammatory bowel disease has already been sufficiently reported. However, the results of these studies are inconsistent. Hence, this analysis was conducted to investigate whether anti-tumour necrosis factor alpha agents can increase the risk of lymphoma in inflammatory bowel disease patients.

METHODS

MEDLINE, EMBASE, and the Cochrane Library were searched to identify relevant studies which evaluated the risk of lymphoma in inflammatory bowel disease patients treated with anti-tumour necrosis factor alpha agents. A random-effects meta-analysis was performed to calculate the pooled incidence rate ratios as well as risk ratios.

RESULTS

Twelve studies comprising 285,811 participants were included. The result showed that there was no significantly increased risk of lymphoma between anti-tumour necrosis factor alpha agents exposed and anti-tumour necrosis factor alpha agents unexposed groups (random effects: incidence rate ratio [IRR] = 1.43, 95% CI, 0.91-2.25; P = 0.116; random effects: risk ratio [RR] = 0.83, 95% CI, 0.47-1.48; P = 0.534). However, monotherapy of anti-tumour necrosis factor alpha agents [random effects: IRR = 1.65, 95% CI, 1.16-2.35; P = 0.006; random effects: RR = 1.00, 95% CI, 0.39-2.59; P = 0.996] or combination therapy [random effects: IRR = 3.36, 95% CI, 2.23-5.05; P < 0.001; random effects: RR = 1.90, 95% CI, 0.66-5.44; P = 0.233] can significantly increase the risk of lymphoma.

CONCLUSIONS

Exposition of anti-tumour necrosis factor alpha agents in patients with inflammatory bowel disease is not associated with a higher risk of lymphoma. Combination therapy and anti-tumour necrosis factor alpha agents monotherapy can significantly increase the risk of lymphoma in patients with inflammatory bowel disease.

Systematic analyses of drugs and disease indications in RepurposeDB reveal pharmacological, biological and epidemiological factors influencing drug repositioning

Increase in global population and growing disease burden due to the emergence of infectious diseases (Zika virus), multidrug-resistant pathogens, drug-resistant cancers (cisplatin-resistant ovarian cancer) and chronic diseases (arterial hypertension) necessitate effective therapies to improve health outcomes. However, the rapid increase in drug development cost demands innovative and sustainable drug discovery approaches. Drug repositioning, the discovery of new or improved therapies by reevaluation of approved or investigational compounds, solves a significant gap in the public health setting and improves the productivity of drug development. As the number of drug repurposing investigations increases, a new opportunity has emerged to understand factors driving drug repositioning through systematic analyses of drugs, drug targets and associated disease indications. However, such analyses have so far been hampered by the lack of a centralized knowledgebase, benchmarking data sets and reporting standards. To address these knowledge and clinical needs, here, we present RepurposeDB, a collection of repurposed drugs, drug targets and diseases, which was assembled, indexed and annotated from public data. RepurposeDB combines information on 253 drugs [small molecules (74.30%) and protein drugs (25.29%)] and 1125 diseases. Using RepurposeDB data, we identified pharmacological (chemical descriptors, physicochemical features and absorption, distribution, metabolism, excretion and toxicity properties), biological (protein domains, functional process, molecular mechanisms and pathway cross talks) and epidemiological (shared genetic architectures, disease comorbidities and clinical phenotype similarities) factors mediating drug repositioning. Collectively, RepurposeDB is developed as the reference database for drug repositioning investigations. The pharmacological, biological and epidemiological principles of drug repositioning identified from the meta-analyses could augment therapeutic development.

Anti-TNFα therapy for chronic inflammatory disease in kidney transplant recipients: Clinical outcomes

Anti-tumor necrosis factor-α (TNFα) therapy has improved the prognosis of many chronic inflammatory diseases. It appears to be well-tolerated by liver-transplant patients. However, their use and their safety in kidney-transplant patients have yet to be determined.In this retrospective study, we identified 16 adult kidney-transplant patients aged 46.5 years (34-51.8) who received anti-TNFα therapy from 7 kidney transplantation centers. The indications for this treatment included: chronic inflammatory bowel disease (n = 8), inflammatory arthritis (n = 5), AA amyloidosis (n = 1), psoriasis (n = 1), and microscopic polyangiitis (n = 1).Anti-TNFα therapies resulted in a clinical response in 13/16 patients (81%). Estimated glomerular filtration rates (MDRD-4) were similar on day 0 and at 24 months (M24) after anti-TNFα treatment had been initiated (41 [12-55] and 40 [21-53] mL/min/1.73 m, respectively). Two allograft losses were observed. The 1st case was due to antibody-mediated rejection (M18), while the 2nd was the result of AA amyloidosis recurrence (M20). There were several complications: 8 patients (50%) developed 23 serious infections (18 bacterial, 4 viral, and 1 fungal) and 4 developed cancer. Five patients died (infection n = 2, cardiac AA amyloidosis n = 1, intraalveolar hemorrhage following microscopic polyangiitis n = 1, and acute respiratory distress syndrome n = 1). On univariate analysis, recipient age associated with death (P = 0.009) and infection development (P = 0.06).Using anti-TNFα therapies, remission can be achieved in chronic inflammatory diseases in kidney-transplant patients. However, concommitant anti-TNFα and immunosuppresive therapies must be used with caution due to the high risk of infection, particularly after the age of 50.

Update on pathogenesis and predictors of response of therapeutic strategies used in inflammatory bowel disease

The search for biomarkers that characterize specific aspects of inflammatory bowel disease (IBD), has received substantial interest in the past years and is moving forward rapidly with the help of modern technologies. Nevertheless, there is a direct demand to identify adequate biomarkers for predicting and evaluating therapeutic response to different therapies. In this subset, pharmacogenetics deserves more attention as part of the endeavor to provide personalized medicine. The ultimate goal in this area is the adjustment of medication for a patient’s specific genetic background and thereby to improve drug efficacy and safety rates. The aim of the following review is to utilize the latest knowledge on immunopathogenesis of IBD and update the findings on the field of Immunology and Genetics, to evaluate the response to the different therapies. In the present article, more than 400 publications were reviewed but finally 287 included based on design, reproducibility (or expectancy to be reproducible and translationable into humans) or already measured in humans. A few tests have shown clinical applicability. Other, i.e., genetic associations for the different therapies in IBD have not yet shown consistent or robust results. In the close future it is anticipated that this, cellular and genetic material, as well as the determination of biomarkers will be implemented in an integrated molecular diagnostic and prognostic approach to manage IBD patients.

The roles of host and pathogen factors and the innate immune response in the pathogenesis of Clostridium difficile infection

Clostridium difficile (C. difficile) is the most common cause of nosocomial antibiotic-associated diarrhea and the etiologic agent of pseudomembranous colitis. The clinical manifestation of C. difficile infection (CDI) is highly variable, from asymptomatic carriage, to mild self-limiting diarrhea, to the more severe pseudomembranous colitis. Furthermore, in extreme cases, colonic inflammation and tissue damage can lead to toxic megacolon, a condition requiring surgical intervention. C. difficile expresses two key virulence factors; the exotoxins, toxin A (TcdA) and toxin B (TcdB), which are glucosyltransferases that target host-cell monomeric GTPases. In addition, some hypervirulent strains produce a third toxin, binary toxin or C. difficile transferase (CDT), which may contribute to the pathogenesis of CDI. More recently, other factors such as surface layer proteins (SLPs) and flagellin have also been linked to the inflammatory responses observed in CDI. Although the adaptive immune response can influence the severity of CDI, the innate immune responses to C. difficile and its toxins play crucial roles in CDI onset, progression, and overall prognosis. Despite this, the innate immune responses in CDI have drawn relatively little attention from clinical researchers. Targeting these responses may prove useful clinically as adjuvant therapies, especially in refractory and/or recurrent CDI. This review will focus on recent advances in our understanding of how C. difficile and its toxins modulate innate immune responses that contribute to CDI pathogenesis.

Drug therapies and the risk of malignancy in Crohn's disease: results from the TREAT™ Registry

OBJECTIVES

We assessed potential associations between malignancy and antitumor necrosis factor therapy in patients with Crohn's disease (CD), as this relationship is currently poorly defined.

METHODS

Utilizing data from the Crohn's Therapy, Resource, Evaluation, and Assessment Tool (TREAT™) Registry, a prospective cohort study examining long-term outcomes of CD treatments in community and academic settings, influences of baseline patient/disease characteristics and medications were assessed by survival analysis and multivariate models. Standardized incidence ratios and exact 95 % confidence intervals were determined as the ratio of events observed (TREAT) vs. expected (general population of USA).

RESULTS

As of 23 February 2010, 6,273 CD patients (infliximab during registry=3,420 (during or within 1 year before registry=3,764); other-treatments-only: 2,509), were enrolled and, on average, had been followed for 5.2/7.6 years, respectively, for all/currently active patients. Crude cancer incidences were similar between infliximab- and other-treatments-only-exposed patients. Multivariate Cox regression analysis demonstrated that baseline age (hazard ratio (HR)=1.59/10 years; P<0.001), disease duration (HR=1.64/10 years; P=0.012), and smoking (HR=1.38; P=0.045) but neither immunosuppressive therapy alone (HR=1.43; P=0.11), infliximab therapy alone (HR=0.59; P=0.16), nor their combination (HR=1.22, P=0.34) were independently associated with the risk of malignancy. When compared with the general population, no significant increase in incidence was observed in any malignancy category. In an exposure-based analysis, use of immunosuppressants alone (odds ratio=4.19) or in combination with infliximab (3.33) seemed to be associated with a numerically, but not significantly, greater risk of malignancy than did treatment with infliximab alone (1.96) relative to treatment with neither.

CONCLUSIONS

In the TREAT Registry, age, disease duration, and smoking were independently associated with increased risk of malignancy. Although results for immunosuppressant use were equivocal, no significant association between malignancy and infliximab was observed.

Clinical pharmacology and pharmacogenetics of thiopurines

The thiopurine drugs-azathioprine (AZA), 6-mercaptopurine (6-MP), and thioguanine-are widely used to treat malignancies, rheumatic diseases, dermatologic conditions, inflammatory bowel disease, and solid organ transplant rejection. However, thiopurine drugs have a relatively narrow therapeutic index and are capable of causing life-threatening toxicity, most often myelosuppression. Thiopurine S-methyltransferase (TPMT; EC 2.1.1.67), an enzyme that catalyzes S-methylation of these drugs, exhibits a genetic polymorphism in 10% of Caucasians, with 1/300 individuals having complete deficiency. Patients with intermediate or deficient TPMT activity are at risk for excessive toxicity after receiving standard doses of thiopurine medications. This report reviews the recent advances in the knowledge of the mechanism of action as well as the molecular basis and interethnic variations of TPMT and inosine triphosphate pyrophosphatase (ITPase; EC 3.6.1.19), another enzyme implicated in thiopurine toxicity. In addition, an update on pharmacokinetics, metabolism, drug-drug interactions, safety, and tolerability of thiopurine drugs is provided.

Pharmacogenetics of Crohn’s disease

The considerable interindividual differences in efficacy and side effects of commonly used medications in Crohn’s disease are partly owing to genetic polymorphisms. Many genetic variants have been studied in genes possibly involved in the metabolism or mechanism of action of therapeutic agents such as glucocorticosteroids, azathioprine/6-mercaptopurine, methotrexate, calcineurin inhibitors or anti-TNF agents. However, the only test translated into clinical practice is thiopurine S-methyltransferase (TPMT) genotyping for hematological toxicity of thiopurine treatment. To date, there are no other meaningful applications for pharmacogenomics in clinical practice of Crohn’s disease. In the future, designed therapeutic trials should possibly permit the development of predictive models including genotypic markers, such as that proposed for the clinical outcome after infliximab therapy, which includes an apoptotic pharmacogenetic index. The recent identification of new susceptibility genes provides additional candidate markers that have possible effects on the outcomes of therapies, and prioritizes new therapeutic targets, such as the IL-23 pathway. Futher innovative approaches might be relevant for the pharmacogenetic investigation of gene variants implied in innate immune pattern recognition and autophagy.

Murine TNF(DeltaARE) Crohn's disease model displays diminished expression of intestinal Ca2+ transporters

BACKGROUND

Patients suffering from Crohn's disease (CD) show increased incidence of low bone mineral density. Investigating this complication is difficult because the exact etiology of CD remains elusive. Mice carrying a deletion in the tumor necrosis factor (TNF) AU-rich elements (ARE) are reported as a model for human CD and are characterized by elevated TNF-alpha levels and inflammations in the terminal ileum. To evaluate whether these mice have a Ca(2+) handling problem, this study analyzed the Ca(2+) homeostasis in heterozygous TNF(DeltaARE) mice (TNF(DeltaARE/+)) in comparison to wildtype littermates.

METHODS

Beside serum Ca(2+) and vitamin D levels, the expression of Ca(2+) transporters was analyzed in intestine, kidney and bone using quantitative real-time PCR, Western blot and immunohistochemistry. Bone scans were performed to measure bone parameters.

RESULTS

Ca(2+) transporters in duodenum (TRPV6, calbindin-D(9K), PMCA1b) and kidney (TRPV5, calbindin-D(28K), NCX1) showed significantly reduced mRNA expression levels in TNP(DeltaARE/+) mice, except for renal TRPV5. In bone, only calbindin-D(9K) mRNA displayed a significant down-regulation. These findings were supported by declined duodenal calbindin-D(9K) and renal calbindin-D(28K) protein values. Likely, this down-regulation of Ca(2+) transporters in TNP(DeltaARE/+) mice is mediated by the 58 +/- 9% reduction in serum 1,25(OH)(2)D(3) levels. Diminished expression of Ca(2+) transporters combined with unchanged serum Ca(2+) levels assumes Ca(2+) loss from bone to compensate for the body's overall Ca(2+) shortage. Indeed, microcomputed tomography scanning demonstrated reduced trabecular and corticol bone thickness and volume in TNF(DeltaARE/+) mice. This finding is further supported by increased total deoxypyridinoline in serum.

CONCLUSIONS

Our results imply that TNF(DeltaARE/+) mice have a disturbed Ca(2+) homeostasis characterized by reduced duodenal and renal Ca(2+) transporters, diminished 1,25(OH)(2)D(3) levels, and increased bone resorption associated with profound bone abnormalities.

Tolerability and safety of mercaptopurine in azathioprine-intolerant patients with inflammatory bowel disease

BACKGROUND

Azathioprine intolerance is a common clinical problem, requiring drug withdrawal in up to 30% of patients. The successful use of mercaptopurine is described, but data to support this strategy are needed.

AIMS

To assess the tolerability of mercaptopurine in inflammatory bowel disease patients previously intolerant of azathioprine, and identify predictive factors.

METHODS

Sixty-one azathioprine-intolerant patients (31 males, median age at diagnosis 32 years, 31 with Crohn's disease, 30 with ulcerative colitis) who had been treated with mercaptopurine were identified. Intolerances included nausea and vomiting, flu-like illness, neutropenia, hepatotoxicity and pancreatitis.

RESULTS

Mercaptopurine was tolerated by 59% (36 of 61) of azathioprine-intolerant patients (median dose 1.0 mg/kg), 61% (17 of 28) in patients with azathioprine-related nausea and vomiting, 61% (11 of 18) with flu-like illness, 33% (three of nine) with hepatotoxicity, 100% (one of one) with neutropenia, 100% (three of three) with rash and 0% (zero of one) with pancreatitis. Mercaptopurine intolerance was frequently for a different adverse event. Those intolerant of mercaptopurine were younger (28.4 years vs. 37.0 years; P = 0.014) and more frequently female (14/30 vs. 2/29, P = 0.027). Mercaptopurine tolerability was not affected by diagnosis, location, behaviour, surgery, smoking, family history or extra-intestinal manifestations.

CONCLUSION

Mercaptopurine may be tolerated in up to 60% of azathioprine-intolerant patients, and treatment should be considered, particularly if intolerance was due to nausea, vomiting, flu-like illness or rash.

The intestinal anti-inflammatory effects of the novel agent UR-1505 in the TNBS model of rat colitis are mediated by T-lymphocyte inhibition

UR-1505 is a novel pentafluoropropoxy derivative of salicylic acid, selected from a series of salicylate derivatives, according to their activity as inhibitors of T-lymphocyte activation. This study describes the anti-inflammatory activity of UR-1505 on trinitrobenzenesulphonic acid-induced colitis in rat, an experimental model that resembles to Crohn's disease (CD), as well as its in vitro effects on T-cells and bone marrow-derived macrophages (BMDM) activation. UR-1505 showed intestinal anti-inflammatory effect, associated with reduced colonic levels of TNFalpha and LTB(4), inhibition of the expression of IFNgamma and iNOS, and lower colonic leukocyte infiltration. The in vitro assays revealed that UR-1505 also inhibited T-lymphocyte proliferation and IL-12/IFNgamma production, two of the main pro-inflammatory cytokines involved in the pathogenesis of CD. However, UR-1505 did not modify LPS- nor IFNgamma-induced activation in BMDM. Thus, UR-1505 specifically affects T-cells without modifying the activation of BMDM. In conclusion, the intestinal anti-inflammatory activity of UR-1505 seems to be mediated by a reduction in the recruitment of immune cells to the inflammatory foci, together with the inhibition of T-cell activation. These results suggest that UR-1505 may be an interesting candidate to be explored for the treatment of CD.

Inhibition of inducible tumor necrosis factor-α expression by the fungal epipolythiodiketopiperazine gliovirin

TNF-alpha is a major pro-inflammatory cytokine that regulates further cytokine induction, especially of IL-1 and IL-6, in many human diseases including cancer, inflammation and immune disorders. In a search for new inhibitors of inducible TNF-alpha promoter activity and expression, cultures of the imperfect fungus Trichoderma harzianum were found to produce gliovirin, a previously isolated epipolythiodiketopiperazine. Gliovirin inhibited inducible TNF-alpha promoter activity and synthesis in LPS/IFN-gamma-stimulated macrophages/monocytes and Jurkat T-cells, co-stimulated with 12-O-tetradecanoylphorbol-13-acetate (TPA)/ionomycin, in a dose-dependent manner, with IC(50) values ranging from 0.21 to 2.1 microM (0.1-1 microg/ml). Studies on the mode of action revealed that gliovirin suppresses TNF-alpha synthesis by inhibiting the activation of extracellular signal-regulated kinase (ERK), thereby blocking the pathway leading to activation of the transcription factors AP-1 and NF-kappaB, the latter of which is involved in the inducible expression of many pro-inflammatory genes. Gliovirin also significantly reduced TPA/ionomycin-induced IL-2 mRNA levels and synthesis in Jurkat cells at low micromolar concentrations.

Incidence and risk factors for herpes zoster among patients with inflammatory bowel disease

BACKGROUND & AIMS

An increased risk of herpes zoster in patients with inflammatory bowel disease (IBD) is hypothesized based on altered immune function, especially among patients receiving immunosuppressive medications.

METHODS

We performed a retrospective cohort study and a retrospective nested case-control study using 1988-1997 data from the General Practice Research Database. In the cohort study, 7823 Crohn's disease (CD) and 11,930 ulcerative colitis (UC) patients were matched on age, sex, and primary care practice to 79,563 randomly selected controls without CD or UC. In the nested case-control study, 185 CD patients with zoster and 266 UC patients with zoster were matched on sex and year of birth to 1787 IBD patients without zoster.

RESULTS

In the cohort study, the incidence of zoster was higher in patients with CD and UC compared with their matched controls (UC incidence rate ratio, 1.21; 95% confidence interval [CI], 1.05-1.40; CD incidence rate ratio, 1.61; 95% CI, 1.35-1.92). In the nested case-control study, receipt of a prescription for corticosteroids (adjusted odds ratio, 1.5; 95% CI, 1.1-2.2) or azathioprine/6-mercaptopurine (adjusted odds ratio, 3.1; 95% CI, 1.7-5.6) were both associated with zoster.

CONCLUSIONS

Patients with IBD, especially those on immunosuppressive medications, are at higher risk for herpes zoster compared with the general population. Future studies should clarify the relative risk associated with anti-tumor necrosis factor alpha therapies and determine the use of the new zoster vaccine for patients with IBD.

Oral ulcerations are associated with the loss of response to infliximab in Crohn's disease

We describe a 25-year-old Caucasian man with a 13-year history of inflammatory Crohn's disease (CD) who was suffering recurrent severe oral and esophageal ulcerations for the past 3 years. His CD had been treated with infliximab infusions among other medications. The loss of efficacy was confirmed by antibodies to infliximab (ATI) and serum infliximab tests that showed high levels of ATIs and undetectable levels of infliximab respectively. These findings were consistent with significant immunogenic response to infliximab leading to loss of effect. Infliximab infusions and prednisone were discontinued and treatment of the CD was instituted with adalimumab, a human anti-tumor necrosis factor (TNF)-alpha biologic agent, to control the inflammatory small intestinal disease and dapsone for the oral and esophageal CD ulcerations. The patient's oral and esophageal lesions as well as the enteric CD are under control after 5 months of therapy.

Calcium and 1 alpha,25-dihydroxyvitamin D3 target the TNF-alpha pathway to suppress experimental inflammatory bowel disease

Vitamin D-deficient IL-10 knockout (KO) mice develop accelerated inflammatory bowel disease (IBD). Removing dietary calcium from the diets of vitamin D-deficient IL-10 KO mice increased the severity of IBD. The mice fed either calcium or active vitamin D (1 alpha,25-dihydroxyvitamin D3, 1,25D3), developed an intermediate form of IBD, while the mice fed both calcium and 1,25D3 had the mildest form of IBD. TNF-alpha secretion from Con A-stimulated splenocytes was reduced by dietary calcium or 1,25D3 treatment. The IL-10 KO mice that received both high calcium diets and 1,25D3 treatments had the lowest TNF-alpha production. In the colons, a TNF-alpha-inducing transcription factor, LPS-induced TNF-alpha factor (LITAF), was inhibited by 1,25D3, but not by calcium. The inhibition of several TNF-alpha-related genes was associated with the decreased colitis in 1,25D3-treated IL-10 KO mice. Furthermore, fulminating IBD in vitamin D receptor/IL-10 double-KO mice corresponded with the increased expression of TNF-alpha and LITAF in the colon. Our results suggest that dietary calcium has independent effects on IBD severity and that 1,25D3 and high calcium together result in the maximal suppression of experimental IBD. The data support a model where dietary calcium and 1,25D3 treatment directly and indirectly inhibit the TNF-alpha pathway and suppress IBD.

Inhibition of inducible TNF-alpha expression by oxaspirodion, a novel spiro-compound from the ascomycete Chaetomium subspirale

In a search for compounds inhibiting the inducible TNF-alpha promoter activity in T cells, a new spiro-compound, designated oxaspirodion, was isolated from fermentations of the ascomycete Chaetomium subspirale. Oxaspirodion inhibited TNF-alpha promoter-driven luciferase reporter gene expression with an IC50 value of 2.5 microg/ml (10 microM) in TPA/ionomycin-stimulated Jurkat T cells. Studies on the mode of action of the compound revealed that the inhibition of the TNF-alpha promoter activity is caused by an inhibition of the phosphorylation of the ERK1/2 kinases. In addition, oxaspirodion inhibited the activation of the transcription factor NF-kappaB, which is involved in the inducible expression of many proinflammatory genes.

Pneumocystis carinii pneumonia during maintenance anti-tumor necrosis factor-alpha therapy with infliximab for Crohn's disease

BACKGROUND

Clinical trials using infliximab have not reported cases of Pneumocystis carinii pneumonia (PCP), and PCP infection during standard medical treatment of inflammatory bowel disease is uncommon. Postmarketing surveillance through June of 2001 has identified 10 cases of PCP occurring during treatment with infliximab; 3 patients died.

CASE HISTORY

A 19-year-old man with Crohn's colitis developed thrush, leukopenia, fever, shortness of breath, and dry cough 21 months after initiating maintenance therapy with azathioprine and infliximab. Azathioprine had been at a stable dose of 75 mg per day (1 mg/kg) and the patient had received his 14th infusion of infliximab 4 weeks prior to presentation. Evaluation revealed the presence of Pneumocystis carinii on induced sputum. Azathioprine was discontinued, and the patient improved after initiating treatment with steroids and trimethoprim-sulfamethoxazole. Follow-up 2 weeks later confirmed clinical response to therapy.

CONCLUSIONS

This case report describes the uncommon occurrence of Pneumocystis pneumonia in the setting of maintenance therapy for Crohn's disease using infliximab and azathioprine. Mechanisms by which azathioprine and infliximab may impair the natural defense mechanisms against Pneumocystis are discussed.