A multicenter, randomized, double-blind trial of everolimus versus azathioprine and placebo to maintain steroid-induced remission in patients with moderate-to-severe active Crohn's disease

Medical therapy of stricturing Crohn's disease: what the gut can learn from other organs - a systematic review

Crohn’s disease (CD) is a chronic remitting and relapsing disease. Fibrostenosing complications such as intestinal strictures, stenosis and ultimately obstruction are some of its most common long-term complications. Despite recent advances in the pathophysiological understanding of CD and a significant improvement of anti-inflammatory therapeutics, medical therapy for stricturing CD is still inadequate. No specific anti-fibrotic therapy exists and the incidence rate of strictures has essentially remained unchanged. Therefore, the current therapy of established fibrotic strictures comprises mainly endoscopic dilation as well as surgical approaches. However, these treatment options are associated with major complications as well as high recurrence rates. Thus, a specific anti-fibrotic therapy for CD is urgently needed. Importantly, there is now a growing body of evidence for prevention as well as effective medical treatment of fibrotic diseases of other organs such as the skin, lung, kidney and liver. In face of the similarity of molecular mechanisms of fibrogenesis across these organs, translation of therapeutic approaches from other fibrotic diseases to the intestine appears to be a promising treatment strategy. In particular transforming growth factor beta (TGF-β) neutralization, selective tyrosine kinase inhibitors, blockade of components of the renin-angiotensin system, IL-13 inhibitors and mammalian target of rapamycin (mTOR) inhibitors have emerged as potential drug candidates for anti-fibrotic therapy and may retard progression or even reverse established intestinal fibrosis. However, major challenges have to be overcome in the translation of novel anti-fibrotics into intestinal fibrosis therapy, such as the development of appropriate biomarkers that predict the development and accurately monitor therapeutic responses. Future clinical studies are a prerequisite to evaluate the optimal timing for anti-fibrotic treatment approaches, to elucidate the best routes of application, and to evaluate the potential of drug candidates to reach the ultimate goal: the prevention or reversal of established fibrosis and strictures in CD patients.

Patterns of 6-mercaptopurine and azathioprine maintenance therapy among a cohort of commercially insured individuals diagnosed with Crohn's disease in the United States

BACKGROUND AND AIMS

Thiopurines, including 6-mercaptopurine (6-MP) and azathioprine (AZA), are the mainstay of maintenance therapy for Crohn's disease (CD). However, studies examining their effectiveness in routine practice among diverse patient populations are lacking. Among a cohort of new users of 6MP/AZA, we described treatment patterns and changes in subsequent therapy.

METHODS

Using the Truven Health Analytics databases, we identified all individuals diagnosed with CD and initiating 6-MP/AZA monotherapy from 2001-2008 (n=3,657). We estimated the proportion of CD patients remaining on 6-MP/AZA monotherapy, using Kaplan-Meier methods, and identified predictors of treatment noncontinuation, using multivariable Cox regression. Among the "noncontinuers," we described subsequent patterns of maintenance therapy and summarized the diagnosis and procedure codes and prescription drug claims preceding treatment discontinuation.

RESULTS

The 1-year 6-MP/AZA treatment continuation rate was 42%. Children (age ≤18 years) and individuals with no prior anti-tumor necrosis factor (TNF) use were more likely to continue 6-MP/AZA, while those dispensed more (>4) outpatient prescriptions for any drug before initiation of 6-MP/AZA were less likely to continue maintenance treatment. Overall, 1,128 (39%) and 105 (4%) individuals experienced a clinical event potentially indicating active disease or 6-MP/AZA-intolerance prior to discontinuation, respectively. Most patients discontinued therapy; among the remaining patients who failed to continue 6-MP/AZA, most augmented with an anti-TNF.

CONCLUSION

Most patients initiating 6-MP/AZA monotherapy did not continue beyond 1 year. In contrast to trial evidence showing 1-year remission rates of 40%-80%, this study observed a lower effectiveness of 6-MP/AZA treatment, possibly due to differences in disease severity, patient demographics, comorbidity, adherence, and health care utilization.

Comparing medical treatments for Crohn's disease

The drugs available for inflammatory bowel disease are aminosalicylates, antibiotics, steroids, immunosuppressors and biologics. The effectiveness of these drugs has been evaluated in many randomized clinical trials, mainly versus placebo. Few studies have been conducted comparing the different drugs among themselves, owing to the methodological problems raised by comparative trials, such as sample size and blindness. This review focuses mainly on the randomized clinical trials that have compared different treatments. Of course comparisons are mainly between drugs used in a particular setting (mild, moderate and severe disease). However, on many occasions there is no homogeneity in these clinical settings, and therefore the results are difficult to interpret.

Autophagy at the crossroads of metabolism and cellular defense

PURPOSE OF REVIEW

From its initial description as a homeostatic process required for starvation response, autophagy has emerged as a ubiquitous cellular process involved in a broad range of cellular activities from metabolic adaptation to cellular defense against invading pathogens. This review provides an overview of autophagy and highlights the recent developments in deciphering its role in metabolic adaptation and its importance in antibacterial defense with attention to regulatory pathways.

RECENT FINDINGS

Within the last 2 years, there has been significant progress in deciphering the mechanisms by which autophagy is regulated, including subcellular localization, posttranslational modifications, and transcriptional control. In addition, the cell type-specific role of autophagy in maintaining cellular homeostasis has been defined, including its role in handling intracellular pathogens and its contribution to inflammatory bowel disease.

SUMMARY

Autophagy is a critical pathway that integrates numerous regulatory inputs to maintain cellular homeostasis and defend against intracellular pathogens.

Use of immunosuppressants and biologicals in patients with previous cancer

Thiopurines promote Epstein-Barr virus-related lymphomas, nonmelanoma skin cancers and acute myeloid leukemias. Anti-tumor necrosis factor (anti-TNF) agents may inhibit or activate carcinogenesis according to the cellular pathways that are activated. A mild increase in the risk of melanoma has been reported in patients exposed to anti-TNF agents. Transplanted patients with previous history of cancer are at high risk of cancer recurrence when receiving posttransplant immunosuppressive therapy, particularly within the first 2 years of treatment. Few data exist for patients with chronic inflammatory disease. In the CESAME cohort that included essentially patients receiving thiopurines, there was no excess incidence of recurrent or new cancer associated with exposure to immunosuppressive therapy in the patients with previous cancer at cohort entry. In clinical practice, the decision to start or resume immunosuppressive therapy in inflammatory bowel disease (IBD) patients with recent cancer should be discussed case by case with cancer specialists. However, taken into account the experience of transplant specialists, it could be suggested not to consider a waiting period for women with adequately treated uterine high-grade cervical dysplasia. For invasive cancers, a waiting period of 2 years should be considered if possible. During this period, treatment of IBD should be restricted to 5-aminosalicylic acid, steroids, nutritional therapy, or surgery, except in case of aggressive IBD that cannot be controlled by these methods. A longer waiting period of 5 years could be recommended for the most aggressive forms of cancers, such as melanomas, aggressive breast cancers, sarcomas, urinary tract cancers, and myelomas.

ACE2 - from the renin-angiotensin system to gut microbiota and malnutrition

The renin-angiotensin system (RAS) is a complex network that regulates blood pressure, electrolyte and fluid homeostasis, as well as the function of several organs. Angiotensin-converting enzyme 2 (ACE2) was identified as an enzyme that negatively regulates the RAS by converting Ang II, the main bioactive molecule of the RAS, to Ang 1-7. Thus, ACE2 counteracts the role of angiotensin-converting enzyme (ACE) which generates Ang II from Ang I. ACE and ACE2 have been implicated in several pathologies such as cardiovascular and renal disease or acute lung injury. In addition, ACE2 has functions independent of the RAS: ACE2 is the receptor for the SARS coronavirus and ACE2 is essential for expression of neutral amino acid transporters in the gut. In this context, ACE2 modulates innate immunity and influences the composition of the gut microbiota, which can explain diarrhea and intestinal inflammation observed in Hartnup disorder, Pellagra, or under conditions of severe malnutrition. Here we review and discuss the diverse functions of ACE2 and its relevance to human pathologies.

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.

Autophagy: a new target or an old strategy for the treatment of Crohn's disease?

In the past 5 years much progress has been made in understanding the molecular basis of Crohn's disease, a multifactorial chronic inflammatory disease of the gastrointestinal tract. Data suggest that hampered autophagy--the major lysosomal pathway for recycling of cytoplasmic material--might contribute to an increased susceptibility to Crohn's disease. Consequently, intense investigations have started to evaluate the potential value of autophagy as a therapeutic target and as a highly needed diagnostic tool. Interestingly, as well as the promising introduction of direct autophagic modulators, several drugs already used in the treatment of Crohn's disease might exert at least part of their effect through the regulation of autophagy. However, whether this phenomenon contributes to or rather counteracts their therapeutic use, remains to be determined and might prove to be highly compound-specific. Here we review the complex and emerging role of autophagy modulation in the battle against Crohn's disease. Moreover, we discuss the potential benefits and deleterious effects of autophagic regulation by both new and clinically used drugs.

Azathioprine or 6-mercaptopurine for induction of remission in Crohn's disease

BACKGROUND

The results from controlled clinical trials investigating the efficacy of azathioprine and 6-mercaptopurine for the treatment of active Crohn's disease have been conflicting and controversial. An updated meta-analysis was performed to assess the effectiveness of these drugs for the induction of remission in active Crohn's disease.

OBJECTIVES

The primary objective was to determine the efficacy and safety of azathioprine and 6-mercaptopurine for induction of remission in active Crohn's disease.

SEARCH METHODS

A literature search for relevant studies (inception to June 13, 2012) was performed using MEDLINE, EMBASE and the Cochrane Library. Review articles and conference proceedings were also searched to identify additional studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of oral azathioprine or 6-mercaptopurine compared to placebo or active therapy involving adult patients with active Crohn's disease were selected for inclusion.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent observers based on the intention-to-treat principle. Outcomes of interest included: clinical remission, clinical improvement, fistula improvement or healing, steroid sparing, adverse events, withdrawals due to adverse events and serious adverse events. We calculated the pooled relative risk (RR) and 95% confidence intervals (95% CI) for each outcome. The methodological quality of included studies was evaluated using the Cochrane risk of bias tool. The overall quality of the evidence supporting each outcome was assessed using the GRADE criteria.

MAIN RESULTS

Thirteen RCTs (n = 1211 patients) of azathioprine and 6-mercaptopurine therapy in adult patients were identified: nine included placebo comparators and six included active comparators. The majority of included studies were rated as low risk of bias. There was no statistically significant difference in clinical remission rates between azathioprine or 6-mercaptopurine and placebo. Forty-eight per cent (95/197) of patients receiving antimetabolites achieved remission compared to 37% (68/183) of placebo patients (5 studies, 380 patients; RR 1.23, 95% CI 0.97 to 1.55). There was no statistically significant difference in clinical improvement rates between azathioprine or 6-mercaptopurine and placebo. Forty-eight per cent (107/225) of patients receiving antimetabolites achieved clinical improvement or remission compared to 36% (75/209) of placebo patients (8 studies, 434 patients; RR 1.26, 95% CI 0.98 to 1.62). There was a statistically significant difference in steroid sparing (defined as prednisone dose < 10 mg/day while maintaining remission) between azathioprine and placebo. Sixty-four per cent (47/163) of azathioprine patients were able to reduce their prednisone dose to < 10 mg/day compared to 46% (32/70) of placebo patients (RR 1.34, 95% CI 1.02 to 1.77). GRADE analyses rated the overall quality of the evidence for the outcomes clinical remission, clinical improvement and steroid sparing as moderate due to sparse data. There was no statistically significant difference in withdrawals due to adverse events or serious adverse events between antimetabolites and placebo. Ten percent of patients in the antimetabolite group withdrew due to adverse events compared to 5% of placebo patients (8 studies, 510 patients; RR 1.70, 95% CI 0.94 to 3.08). Serious adverse events were reported in 14% of patients receiving azathioprine compared to 4% of placebo patients (2 studies, 216 patients; RR 2.57, 95% CI 0.92 to 7.13). Common adverse events reported in the placebo controlled studies included: allergic reactions. leukopenia, pancreatitis and nausea. Azathioprine was significantly inferior to infliximab for induction of steroid-free clinical remission. Thirty per cent (51/170) of azathioprine patients achieved steroid-free remission compared to 44% (75/169) of infliximab patients (1 study, 339 patients; RR 0.68, 95% CI 0.51 to 0.90). The combination of azathioprine and infliximab was significantly superior to infliximab alone for induction of steroid-free clinical remission. Sixty per cent (116/194) of patients in the combined azathioprine and infliximab group achieved steroid-free remission compared to 48% (91/189) of infliximab patients (2 studies, 383 patients; RR 1.23, 95% CI 1.02 to 1.47). Azathioprine or 6-mercaptopurine therapy was found to be no better at inducing steroid free clinical remission compared to methotrexate (RR 1.13, 95% CI 0.85 to 1.49) and 5-aminosalicylate or sulfasalazine (RR 1.24, 95% CI 0.80 to 1.91). There were no statistically significant differences in withdrawals due to adverse events between azathioprine or 6-mercaptopurine and methotrexate (RR 0.78, 95% CI 0.23 to 2.71); between azathioprine or 6-mercaptopurine and 5-aminosalicylate or sulfasalazine (RR 0.98, 95% CI 0.38 to 2.54); between azathioprine and infliximab (RR 1.47, 95% CI 0.96 to 2.23); or between the combination of azathioprine and infliximab and infliximab (RR 1.16, 95% CI 0.75 to 1.80). Common adverse events in the active comparator trials included nausea, abdominal pain, pyrexia and headache.

AUTHORS' CONCLUSIONS

Azathioprine and 6-mercaptopurine offer no advantage over placebo for induction of remission or clinical improvement in active Crohn's disease. Antimetaboilte therapy may allow patients to reduce steroid consumption. Adverse events were more common in patients receiving antimetabolites although differences with placebo were not statistically significant. Azathioprine therapy is inferior to infliximab for induction of steroid-free remission. However, the combination of azathioprine and infliximab was superior to infliximab alone for induction of steroid-free remission.

Use of thiopurines in inflammatory bowel disease

The use of thiopurines as immunosuppression for the treatment of refractory or chronic active inflammatory bowel disease is established for both Crohn's disease and ulcerative colitis. Nevertheless, many questions remain concerning the optimal treatment regimens of azathioprine, 6-mercaptopurine and thioguanine. We will briefly summarize dose recommendations, indications for thiopurine therapy and side effects which are relevant in clinical practice. We discuss some currently debated topics, including the combination of azathioprine and allopurinol, switching of thiopurine therapy in case of side effects, the use of azathioprine in pregnancy, the infection risk using thiopurines and the evidence when to stop thiopurines. Excellent reviews have been published on the thiopurine metabolic pathway which will not be discussed here in detail.

Nutrient modulation of autophagy: implications for inflammatory bowel diseases

During nutrient deprivation, autophagy provides the constituents required to maintain the metabolism essential for survival. Recently, genome-wide association studies have identified genetic determinants for susceptibility to Crohn's disease (CD) such as ATG16L1 and IRGM that are involved in the autophagy pathway. Both disease-carrying NOD2 mutations and ATG16L1 mutations may result in impairment of autophagy. Impairment in autophagy results in impaired clearance of microbes. Ileal CD is associated with Paneth cell loss of function such as decreased production of α-defensins, which may arise from mutations in NOD2 or autophagy genes. Nutrients are able to modify several cellular pathways and in particular autophagy. We summarize the contribution of a variety of dietary components to activate autophagy. Understanding the crosstalk between nutrients and autophagy in the intestine may provide novel targets that have therapeutics potential in intestinal inflammation. Nutrient activation of autophagy may contribute to restoring the Paneth cell loss of function in ileal CD.

Cellular and molecular mechanisms of intestinal fibrosis

Fibrosis is a chronic and progressive process characterized by an excessive accumulation of extracellular matrix (ECM) leading to stiffening and/or scarring of the involved tissue. Intestinal fibrosis may develop in several different enteropathies, including inflammatory bowel disease. It develops through complex cell, extracellular matrix, cytokine and growth factor interactions. Distinct cell types are involved in intestinal fibrosis, such as resident mesenchymal cells (fibroblasts, myofibroblasts and smooth muscle cells) but also ECM-producing cells derived from epithelial and endothelial cells (through a process termed epithelial- and endothelial-mesenchymal transition), stellate cells, pericytes, local or bone marrow-derived stem cells. The most important soluble factors that regulate the activation of these cells include cytokines, chemokines, growth factors, components of the renin-angiotensin system, angiogenic factors, peroxisome proliferator-activated receptors, mammalian target of rapamycin, and products of oxidative stress. It soon becomes clear that although inflammation is responsible for triggering the onset of the fibrotic process, it only plays a minor role in the progression of this condition, as fibrosis may advance in a self-perpetuating fashion. Definition of the cellular and molecular mechanisms involved in intestinal fibrosis may provide the key to developing new therapeutic approaches.

ACE2 links amino acid malnutrition to microbial ecology and intestinal inflammation

Malnutrition affects up to one billion people in the world and is a major cause of mortality. In many cases, malnutrition is associated with diarrhoea and intestinal inflammation, further contributing to morbidity and death. The mechanisms by which unbalanced dietary nutrients affect intestinal homeostasis are largely unknown. Here we report that deficiency in murine angiotensin I converting enzyme (peptidyl-dipeptidase A) 2 (Ace2), which encodes a key regulatory enzyme of the renin-angiotensin system (RAS), results in highly increased susceptibility to intestinal inflammation induced by epithelial damage. The RAS is known to be involved in acute lung failure, cardiovascular functions and SARS infections. Mechanistically, ACE2 has a RAS-independent function, regulating intestinal amino acid homeostasis, expression of antimicrobial peptides, and the ecology of the gut microbiome. Transplantation of the altered microbiota from Ace2 mutant mice into germ-free wild-type hosts was able to transmit the increased propensity to develop severe colitis. ACE2-dependent changes in epithelial immunity and the gut microbiota can be directly regulated by the dietary amino acid tryptophan. Our results identify ACE2 as a key regulator of dietary amino acid homeostasis, innate immunity, gut microbial ecology, and transmissible susceptibility to colitis. These results provide a molecular explanation for how amino acid malnutrition can cause intestinal inflammation and diarrhoea.

Digesting the genetics of inflammatory bowel disease: insights from studies of autophagy risk genes

The success of genetic analyses identifying multiple loci associated with inflammatory bowel disease (IBD) susceptibility has resulted in the identification of several risk genes linked to a common cellular process called autophagy. Autophagy is a process involving the encapsulation of cytosolic cellular components in double-membrane vesicles, their subsequent lysosomal degradation, and recycling of the degraded components for use by the cell. It plays an important part in the innate immune response to a variety of intracellular pathogens, and it is this component of autophagy that appears to be defective in IBD. This has lead to the hypothesis that Crohn's disease may result from an impaired antibacterial response, which leads to ineffective control of bacterial infection, dysbiosis of the intestinal microbiota, and chronic inflammation. Several recurrent themes have surfaced from studies examining the function of autophagy-related genes in the context of IBD, with cellular context, disease status, risk variant effect, and risk gene interplay all affecting the interpretation of these studies. The identification of autophagy as a major risk pathway in IBD is a significant step forward and may lead to pathway-focused therapy in the future; however, there is more to understand in order to unravel the complexity of this disease.

Medical management of Crohn's disease

INTRODUCTION

The medical approach to Crohn's disease has been modified in recent years thanks to the introduction of new therapies, like biologics. Also, well-designed studies and systematic reviews have allowed better evaluation of the role of old drugs like steroids and immunosuppressors. This review aims to evaluate the recent evidence on the medical approach to Crohn's disease in the different settings of the disease.

AREAS COVERED

Randomized controlled trials and meta-analyses were included in the review. The research on all the studies discussed was based on the Cochrane Library, Medline and Embase, using the following medical subject headings: Crohn's disease, clinical trial, therapy, 5-aminosalicylic acid, steroid, budesonide, immunosuppressant, anti-meta-analysis TNF and biologics.

EXPERT OPINION

In a mild active inflammatory ileocecal disease, budesonide is considered the best approach. The efficacy of aminosalicylates is limited, but a trial that has recently compared aminosalicylates and budesonide has shown that the two drugs are comparable. In a mild colonic disease, sulfasalazine, antibiotics and steroids are effective but the evidence for antibiotics is less clear. The maintenance of remission in this setting is debatable, but sulfasalazine seems the better choice. In a moderate severe ileal and colonic disease, steroids are the best therapy to induce remission. Once remission is reached, immunosuppressors remain today the better choice to maintain the remission. Anti-TNF therapy is indicated in patients intolerant or not responding to steroids and immunosuppressors and in fistulizing Crohn's disease. Early therapy with biologics may be considered in patients with severe disease.

Practical application of anti-TNF therapy for luminal Crohn's disease

Anti-tumor necrosis factor (TNF) therapy to treat inflammatory bowel disease has been available for more than a decade. Although extensive data on the outcome of anti-TNF therapy from individual clinical trials and patient cohorts are available, integrated guidance on the best use of such therapy to achieve optimal clinical outcomes when managing patients with luminal Crohn's disease is lacking. This review combines published data to establish practical strategies for anti-TNF therapy with respect to effective and safe timing of introduction, use of concurrent immunosuppressive therapy, dose escalation, managing relapse, changing drugs, pregnancy and breast feeding, and stopping drug treatment.

Tolerance and efficacy of azathioprine in pediatric Crohn's disease

BACKGROUND

Thiopurines are considered first-line immunomodulators for the prevention of relapse in moderate to severe pediatric Crohn's disease (CD). Early introduction of thiopurines was shown in a pediatric trial to maintain steroid-free remission in 90% of patients for 18 months. In the present study we analyzed the tolerance and efficacy of azathioprine (AZA) to maintain remission in a homogenous single-center observational cohort of children with CD.

METHODS

In all, 105 pediatric CD patients (male/female 68/37) were retrospectively evaluated for the efficacy of AZA (doses 1.4-4 mg/kg) to maintain remission at 6, 12, 18, and 24 months of follow-up. Overall, 93 children were included with active disease (pediatric Crohn's disease activity index [PCDAI] >30), steroid/enteral-nutrition dependency, or postileocecal resection. Remission was defined as PCDAI ≤10 without steroids. Patients requiring antitumor necrosis factor (TNF) medication, other immunomodulators, or surgery were considered to experience a relapse.

RESULTS

Based on PCDAI, steroid-free remission was achieved in 56/93 (60.2%), 37/93 (39.8%), 31/93 (33.3%), and 29/93 (31.2%) at visits month (M)6, M12, M18, and M24, respectively. Within the first 4 weeks, AZA was stopped in 10/93 patients due to adverse reactions (pancreatitis, nausea, vomiting, skin reactions, general weakness), or not introduced due to low thiopurine methyl transferase (TPMT) activity (n = 3). No neutropenia occurred in patients with normal TPMT activity. Three infectious episodes were documented requiring temporary AZA suspension.

CONCLUSIONS

AZA is efficacious in maintaining remission in pediatric CD patients, but to a lesser extent than previously suggested. The majority of patients who are in steroid-free remission at 12 months remained in prolonged remission. Overall tolerance of AZA was excellent.

Autophagy, microbial sensing, endoplasmic reticulum stress, and epithelial function in inflammatory bowel disease

Increasing evidence has emerged that supports an important intersection between 3 fundamental cell biologic pathways in the pathogenesis of inflammatory bowel disease. These include the intersection between autophagy, as revealed by the original identification of ATG16L1 and IRGM as major genetic risk factors for Crohn's disease, and intracellular bacterial sensing, as shown by the importance of NOD2 in autophagy induction upon bacterial entry into the cell. A pathway closely linked to autophagy and innate immunity is the unfolded protein response, initiated by endoplasmic reticulum stress due to the accumulation of misfolded proteins, which is genetically related to ulcerative colitis and Crohn's disease (XBP1 and ORMDL3). Hypomorphic ATG16L1, NOD2, and X box binding protein-1 possess the common attribute of profoundly affecting Paneth cells, specialized epithelial cells at the bottom of intestinal crypts involved in antimicrobial function. Together with their functional juxtaposition in the environmentally exposed intestinal epithelial cell, their remarkable functional convergence on Paneth cells and their behavior in response to environmental factors, including microbes, these 3 pathways are of increasing importance to understanding the pathogenesis of inflammatory bowel disease. Moreover, in conjunction with studies that model deficient nuclear factor-κB function, these studies suggest a central role for altered intestinal epithelial cell function as one of the earliest events in the development of inflammatory bowel disease.

Efficacy of immunosuppressive therapy for inflammatory bowel disease: a systematic review and meta-analysis

OBJECTIVES

There remains controversy regarding the efficacy of thiopurine analogs (azathioprine (AZA) and 6-mercaptopurine (6-MP)), methotrexate (MTX), and cyclosporine for the treatment of inflammatory bowel disease (IBD). We performed an updated systematic review of the literature to clarify the efficacy of immunosuppressive therapy at inducing remission and preventing relapse in ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

Only parallel group randomized controlled trials (RCTs) were considered eligible. Studies with adult IBD patients receiving immunosuppressive therapy compared with placebo for at least 14 days and up to 17 weeks for active disease, or at least 6 months in quiescent disease were analyzed. Two reviewers independently assessed eligibility and extracted data. The primary outcome was remission or relapse using an intention-to-treat analysis. The data were summarized using relative risk (RR) and pooled using a random effects model.

RESULTS

Data on MTX and cyclosporine in IBD were limited although there were some data to support the use of intramuscular MTX in CD but not UC. There were five trials of AZA/6-MP in 380 active CD patients and there was no significant effect of therapy inducing remission (RR=0.87; 95% confidence interval (CI)=0.71-1.06). In quiescent CD, there were two trials involving 198 patients with no significant benefit of active therapy preventing relapse compared with placebo (RR=0.64; 95% CI=0.34-1.23). There were, however, three additional AZA withdrawal trials in 163 patients that indicated continuing medication did prevent relapse (RR=0.39; 95% CI=0.21-0.74). There were two AZA RCTs in 130 active UC patients that suggested a trend for benefit of therapy, but this did not reach statistical significance (RR=0.85; 95% CI=0.71-1.01). In quiescent UC, there were three trials involving 127 patients and there was a statistically significant benefit of AZA preventing relapse (RR=0.60; 95% CI=0.37-0.95).

CONCLUSIONS

Most evidence relates to AZA/6-MP where there is no statistically significant benefit at inducing remission in active CD and UC. Thiopurine analogs may prevent relapse in quiescent UC and CD. However, there is a paucity of data for immunosuppressive therapy in IBD and more research is needed.

Investigational agents for Crohn's disease

IMPORTANCE OF THE FIELD

Increased understanding of the biological mechanisms of Crohn's disease has opened the door to a large number of new molecules; some of these are approved for clinical use, while others remain under evaluation. In this review, we examine the clinical efficacy of all the new drugs that have been evaluated in controlled trials in the last 12 years.

AREAS COVERED IN THIS REVIEW

Anti-TNF therapy has been reviewed briefly, given the many comprehensive reviews on this topic; attention is focused mainly on the other biological therapies. In assessing the clinical efficacy of these molecules, we consider only the remission rate, as this is considered the most meaningful end point in clinical practice.

WHAT THE READER WILL GAIN

We analyzed the main biological mechanisms of Crohn's disease and the new drugs whose use is based on insights into these mechanisms. We reviewed the following new drugs: probiotics, GM-CSF, IL-10, IL-11, anti-IL-6, anti-IL-12/-23, everolimus, anti-IFN-γ, IFN-β-I, co-stimulators, anti-integrins, anti-intercellular adhesion molecule 1, small molecules and mitogen-activated protein kinase inhibitors.

TAKE HOME MESSAGE

Anti-TNF therapies remain the best options, followed by anti-integrin drugs. The most promising new therapies are anti-IL-23, but further data are necessary. The disappointing results with other molecules may depend on the quality of trials and possibly on inadequate dosage of the drug.

Infliximab, azathioprine or combination therapy in the treatment of active Crohn's disease

The treatment of moderate-to-severe steroid-dependent Crohn's disease has been a challenging issue for the gastroenterologist. Until to 10 years ago, immunosuppressors, mainly azathioprine or 6-mercaptopurine, were the best possible treatments available, and remission rates ranged from 30 to 60% according to the results of open studies and controlled trials. Recently, infliximab has been shown to be effective in steroid-dependent patients and, combined with azathioprine, it has been shown to increase 1-year remission rates. A recent large randomized controlled trial comparing infliximab, azathioprine and infliximab plus azathioprine demonstrated that the combination of infliximab plus azathioprine is the most suitable treatment for obtaining steroid-free remission after 26 weeks: steriod-free remission was obtained in 56% of the patients in the infliximab plus azathioprine group versus 44% of patients receiving infliximab alone and 30% of patients receiving azathioprine alone. No relevant differences were observed in the rate of side effects in the three groups of treatments. In this article, the results of this trial are discussed.

Autophagy and Crohn's disease: at the crossroads of infection, inflammation, immunity, and cancer

Inflammatory bowel diseases (IBD) are common inflammatory disorders of the gastrointestinal tract that include ulcerative colitis (UC) and Crohn's disease (CD). The incidences of IBD are high in North America and Europe, affecting as many as one in 500 people. These diseases are associated with high morbidity and mortality. Colorectal cancer risk is also increased in IBD, correlating with inflammation severity and duration. IBD are now recognized as complex multigenetic disorders involving at least 32 different risk loci. In 2007, two different autophagy-related genes, ATG16L1 (autophagy-related gene 16-like 1) and IRGM (immunity-related GTPase M) were shown to be specifically involved in CD susceptibility by three independent genome-wide association studies. Soon afterwards, more than forty studies confirmed the involvement of ATG16L1 and IRGM variants in CD susceptibility and gave new information on the importance of macroautophagy (hereafter referred to as autophagy) in the control of infection, inflammation, immunity and cancer. In this review, we discuss how such findings have undoubtedly changed our understanding of CD pathogenesis. A unifying autophagy model then emerges that may help in understanding the development of CD from bacterial infection, to inflammation and finally cancer. The Pandora's box is now open, releasing a wave of hope for new therapeutic strategies in treating Crohn's disease.

Infliximab, azathioprine, or combination therapy for Crohn's disease

BACKGROUND

The comparative efficacy and safety of infliximab and azathioprine therapy alone or in combination for Crohn's disease are unknown.

METHODS

In this randomized, double-blind trial, we evaluated the efficacy of infliximab monotherapy, azathioprine monotherapy, and the two drugs combined in 508 adults with moderate-to-severe Crohn's disease who had not undergone previous immunosuppressive or biologic therapy. Patients were randomly assigned to receive an intravenous infusion of 5 mg of infliximab per kilogram of body weight at weeks 0, 2, and 6 and then every 8 weeks plus daily oral placebo capsules; 2.5 mg of oral azathioprine per kilogram daily plus a placebo infusion on the standard schedule; or combination therapy with the two drugs. Patients received study medication through week 30 and could continue in a blinded study extension through week 50.

RESULTS

Of the 169 patients receiving combination therapy, 96 (56.8%) were in corticosteroid-free clinical remission at week 26 (the primary end point), as compared with 75 of 169 patients (44.4%) receiving infliximab alone (P=0.02) and 51 of 170 patients (30.0%) receiving azathioprine alone (P<0.001 for the comparison with combination therapy and P=0.006 for the comparison with infliximab). Similar numerical trends were found at week 50. At week 26, mucosal healing had occurred in 47 of 107 patients (43.9%) receiving combination therapy, as compared with 28 of 93 patients (30.1%) receiving infliximab (P=0.06) and 18 of 109 patients (16.5%) receiving azathioprine (P<0.001 for the comparison with combination therapy and P=0.02 for the comparison with infliximab). Serious infections developed in 3.9% of patients in the combination-therapy group, 4.9% of those in the infliximab group, and 5.6% of those in the azathioprine group.

CONCLUSIONS

Patients with moderate-to-severe Crohn's disease who were treated with infliximab plus azathioprine or infliximab monotherapy were more likely to have a corticosteroid-free clinical remission than those receiving azathioprine monotherapy. (ClinicalTrials.gov number, NCT00094458.)

Incidence of delayed graft function and wound healing complications after deceased-donor kidney transplantation is not affected by de novo everolimus

BACKGROUND

Concerns about delayed graft function (DGF) and wound healing complications with sirolimus has led to suggestions that everolimus introduction could be delayed after transplantation.

METHODS

In a prospective, multicenter, open-label study, deceased-donor kidney transplant recipients at protocol-specified risk of DGF (defined as > or =1 dialysis session during the first week posttransplant excluding day 1) were randomized to start everolimus therapy on day 1 posttransplant (immediate everolimus [IE]), or from week 5 (delayed everolimus [DE]) with mycophenolic acid until everolimus was initiated. All patients received anti-interleukin-2 receptor antibodies, cyclosporine A, and corticosteroids. A planned 3-month analysis from this 12-month study is presented here.

RESULTS

One hundred and thirty-nine patients were randomized (IE 65, DE 74). The primary composite endpoint: biopsy-proven acute rejection, graft loss, death, DGF, wound healing events, or lost to follow-up at month 3, occurred in 36 IE patients (55.4%) and 47 DE patients (63.5%, P=0.387). The incidence of DGF was similar between groups (IE 24.6%, DE 24.3%; n.s.). Wound healing events of any type occurred in 40.0% and 41.9% of IE and DE patients (n.s.); events relating to initial transplant surgery occurred in 36.9% IE patients and 37.8% DE patients (n.s.), most of which were fluid collections. Study drug was discontinued due to adverse events or graft loss in 13 IE (20.0%) and 17 DE patients (23.0%).

CONCLUSIONS

Findings from this randomized, multicenter trial indicate that kidney function recovery, wound healing, efficacy, and tolerance are similar at 3 months posttransplant with immediate or DE in patients at protocol-specified risk of DGF.

Positive reasons for publishing negative findings

Scientific and medical authors tend to be biased toward submitting "statistically significant" findings for publication. Journals show a similar bias in publishing such "positive" studies. The large number of publications in medical research means that, in a field obsessed with controlling Type I error rates, we have journals with an abundance of Type I errors. Failing to publish studies that do not show a treatment or exposure effect creates a literature conspicuously absent of trials necessary for unbiased meta-analyses and systematic reviews. Furthermore, by shelving or rejecting studies with nonstatistically significant outcomes, authors and editors censor the most important contributors to medical research: our consenting volunteers.