[Show abstract][Hide abstract] ABSTRACT: Performing well designed and ethical trials in pediatric inflammatory bowel diseases (IBD) is a priority to support optimal therapy and to reduce the unacceptable long lag between adult and pediatric drug approval. Recently, clinical trials in children have been incorporating placebo arms into their protocols under conditions that created controversy. Therefore, four organizations (ESPGHAN, ECCO, the Canadian Children IBD Network and the global pediatric IBD network (PIBDnet)) jointly provide a statement on the role of placebo in pediatric IBD trials. Consensus was achieved by 94/100 (94%) voting committees' members that placebo should only be used if there is genuine equipoise between the active treatment and placebo. For example, this may be considered in trials of drugs with new mechanisms of action without existing adult data, especially when proven effective alternatives do not exist outside the trial. Placebo may also be used in situations where it is an 'add-on" to an effective therapy or to evaluate exit-strategies of maintenance therapy after long-term deep remission. However, it has been agreed that no child enrolled in a trial should receive a known inferior treatment both within and outside the trial. This also includes withholding therapy in children who show clinical response after a short induction therapy. Given the similarity between pediatric and adult IBD in regards to pathophysiology and response to treatments, drugs generally cannot be considered being in genuine equipoise with placebo if it has proven efficacy in adults. Continued collaboration of all stakeholders is needed to facilitate drug development and evaluation in pediatric IBD.
Full-text · Article · Nov 2015 · Journal of pediatric gastroenterology and nutrition
[Show abstract][Hide abstract] ABSTRACT: Crohn's disease and ulcerative colitis are the two major forms of inflammatory bowel disease; treatment strategies have historically been determined by this binary categorisation. Genetic studies have identified 163 susceptibility loci for inflammatory bowel disease, mostly shared between Crohn's disease and ulcerative colitis. We undertook the largest genotype association study, to date, in widely used clinical subphenotypes of inflammatory bowel disease with the goal of further understanding the biological relations between diseases.
[Show abstract][Hide abstract] ABSTRACT: Genome-wide association studies of the related chronic inflammatory bowel diseases (IBD) known as Crohn's disease and ulcerative colitis have shown strong evidence of association to the major histocompatibility complex (MHC). This region encodes a large number of immunological candidates, including the antigen-presenting classical human leukocyte antigen (HLA) molecules. Studies in IBD have indicated that multiple independent associations exist at HLA and non-HLA genes, but they have lacked the statistical power to define the architecture of association and causal alleles. To address this, we performed high-density SNP typing of the MHC in >32,000 individuals with IBD, implicating multiple HLA alleles, with a primary role for HLA-DRB1∗01:03 in both Crohn's disease and ulcerative colitis. Noteworthy differences were observed between these diseases, including a predominant role for class II HLA variants and heterozygous advantage observed in ulcerative colitis, suggesting an important role of the adaptive immune response in the colonic environment in the pathogenesis of IBD.
[Show abstract][Hide abstract] ABSTRACT: The role of Aeromonas species as an enteropathogen in patients with and without inflammatory bowel disease (IBD) is still debated. The aim was to explore the significance of positive Aeromonas stool cultures in IBD and patients without IBD.
Observational retrospective study including all patients with a stool culture positive for Aeromonas between January 2011 and October 2013 at the Leuven University Hospitals. Demographics, clinical, and endoscopic outcomes and laboratory results were analyzed.
A total of 77 patients (11 IBD) were identified. In 37 cases, Aeromonas caused a mild self-limited gastrointestinal infection. Among the 40 patients needing antibiotics, 22 presented a mild-to-moderate gastrointestinal infection; 4 suffered from extraintestinal complications; and 4 were coinfected by Campylobacter spp. A. veronii caused more frequently severe infection than the other species (25% versus 5%; P = 0.046). In 2 patients with ulcerative colitis, Aeromonas triggered a moderate-to-severe flare and 2 cases appeared in the context of de novo Crohn's disease. In contrast, in 1 patient with ulcerative colitis and 2 patients with Crohn's disease, Aeromonas caused a mild gastrointestinal infection not worsening the disease activity and in 4 patients with Crohn's disease, it presented in the context of active disease with no clear pathogenic role. Patients with IBD were treated more often with antibiotics (82 versus 41%, P = 0.012) and had more complications (46 versus 14%, P = 0.024).
Aeromonas caused mostly mild infections but also moderate and severe infections. A. veronii was more prevalent in patients with IBD and was associated with worse clinical outcomes. Aeromonas caused milder infections in patients without IBD. Other risk factors for severe infection were not found.
No preview · Article · Jan 2015 · Inflammatory Bowel Diseases
[Show abstract][Hide abstract] ABSTRACT: Determination of infliximab (IFX) serum concentrations has been used for treatment optimization of patients with inflammatory bowel disease (IBD). A wide range of ELISA assays exists to quantitate IFX. Most of these assays lack specificity and cross-react with other anti-tumor necrosis factor (TNF) agents. The ability of these IFX assays to detect IFX in complex with anti-drug antibodies is not known. The objective of our study was to develop an IFX-specific immunoassay to monitor IFX serum concentrations and to evaluate the impact of anti-drug antibodies on the assay performance.
A panel of monoclonal antibodies towards IFX (MA-IFX) was generated by hybridoma technology and evaluated to replace the polyclonal antibody in a TNF-coated IFX assay. The selected monoclonal antibody-based (MA-based) IFX ELISA was benchmarked to a clinically validated, reference polyclonal antibody-based (pAb-based) IFX ELISA using 209 IBD serum samples.
Fifty-five MA-IFX were generated and grouped into nine clusters. Out of 22 monoclonal antibodies tested, MA-IFX6B7 was selected in the IFX ELISA and the assay was further optimized. MA-IFX6B7 is a high affinity (KD= 1.40E-09 mol/L), non-inhibitory IgG1 antibody, that binds to the Fab fragment of IFX and exhibits no cross-reactivity with other anti-TNF drugs. The linearity of an IFX dose-response curve was demonstrated in the range of 1.2 ng/mL - 37.5 ng/mL (R= 0.988). The MA-based assay showed a good Pearson correlation (R = 0.986) and intraclass correlation coefficient (ICC = 0.985) with the pAb-based assay. The MA-based assay detects IFX in complex with non-neutralizing anti-IFX antibodies but not when complexed with neutralizing anti-IFX antibodies.
In this study, a highly specific MA-IFX was developed as detection antibody in an ELISA to quantify IFX serum concentrations. The assay was benchmarked to the clinically validated reference pAb-based IFX ELISA.
No preview · Article · Dec 2014 · Therapeutic Drug Monitoring
[Show abstract][Hide abstract] ABSTRACT: Background:
Crohn's disease (CD) is associated with an increased risk of small bowel adenocarcinoma (SBA). However, there are no guidelines for the screening and early diagnosis of SBA. Colorectal cancer associated with chronic colitis arises from dysplasia. High-risk patients benefit from surveillance colonoscopies aimed to detect dysplasia. The dysplasia-carcinoma sequence remains poorly documented in CD-associated SBA. Moreover, molecular data about SBA complicating CD and associated dysplasia are very limited. We therefore assessed dysplasia and several key molecular markers of carcinogenesis in SBA and dysplasia developed in patients with CD.
Forty-five SBA complicating CD and 4 specimens with dysplasia without SBA were screened. In SBA, we looked for dysplasia and determined their pathological characteristics (type, grade, distribution). We also stained for mismatch repair proteins (MLH1, MSH2, MSH6, PMS2), p53, β-catenin, and p16 and looked for KRAS, BRAF and PIK3CA mutations.
All neoplastic lesions, except 1 lesion, were found in inflamed mucosal areas. Dysplasia was found in 20 of 41 patients with SBA (49%). Dysplasia was flat or raised, low grade or high grade, and adjacent or distant to concomitant SBA. Molecular markers of SBA carcinogenesis complicating CD were similar to those observed in chronic colitis-related colorectal cancer (KRAS, BRAF, p53, MSI), although differences were observed for β-catenin and p16. No PIK3CA mutations were observed.
These results suggest that there is an inflammation-dysplasia-adenocarcinoma sequence in at least half of CD-related SBA, similar to what is observed in chronic colitis-related colorectal cancer and may have implications for the prevention and treatment of this cancer.
[Show abstract][Hide abstract] ABSTRACT: Inflammatory bowel diseases (IBD) are chronic, relapsing to continuously active inflammatory disorders of the gastrointestinal tract, of potentially destructive nature. So far, the excessive and/or unbalanced immune response has been the target of the majority of the IBD treatments. Despite the increasing use of immunosuppressants and anti-TNF-α inhibitors, about 30% of patients with Crohn's disease and about one-tenth of patients with ulcerative colitis still require major abdominal surgery at 5-10 years. As a result, new therapeutic approaches are urgently needed. The endothelium has a key role in the development of the inflammation, as it selectively governs the leukocyte trafficking and the influx of leukocytes into the intestinal mucosa. Drugs blocking such crossing, specifically at intestinal level, are going to be a new therapeutic option in IBD.
No preview · Article · May 2014 · Expert Review of Clinical Immunology
[Show abstract][Hide abstract] ABSTRACT: Although paediatric-onset IBD is becoming more common, few medications have a registered paediatric indication. There are multiple hurdles to performing clinical trials in children, emphasising the importance of choosing an appropriate outcome measure, which can facilitate enrolment, and thereby also drug approval. The aim of this consensus statement is to highlight paediatric specific issues and key factors critical for the optimal conduct of paediatric IBD trials.
The Paediatric European Crohn's and Colitis Organisation (ECCO) committee has established an international expert panel to determine the best outcome measures in paediatric IBD, following a literature search and a modified Delphi process. All recommendations were endorsed by at least 80% agreement.
Recognising the importance of mucosal healing (MH), the panel defined steroid-free MH as primary outcome measure for all drugs of new category with one or two postintervention endoscopies per trial (at 8-12 weeks and/or 54 weeks). Since endoscopic evaluation is a barrier for recruitment in children, trials with medications already shown to induce MH in children or adults, could use paediatric-specific disease activity scores as primary outcome, including a modified Paediatric Crohn's Disease Activity Index in Crohn's disease and the Paediatric Ulcerative Colitis Activity Index in UC. Secondary outcomes should include safety issues, MR enterography-based damage and inflammatory scores (in Crohn's disease), faecal calprotectin, quality of life scales, and a patient-reported outcome.
It is crucial to perform paediatric trials early in the development of new drugs in order to reduce off-label use of IBD medication in children. The thoughtful choice of feasible and standardised outcome measures can help move us towards this goal.
[Show abstract][Hide abstract] ABSTRACT: Although inflammatory bowel diseases (IBD) significantly impact the patient's quality of life, no European-level data exists on patients' perspectives. The primary objective of this survey was to obtain an international perspective of the impact of IBD on patients' lives. Secondary objectives included obtaining a better understanding of the quality of care, access to care, and differences between countries, age groups, and sub-groups of IBD.
The survey questionnaire consisted of 52 questions in six categories. The survey was translated into ten languages, tested on volunteers, and promoted across 25 national IBD associations. Data was collected anonymously online, and participation was optional.
4670 patients completed the survey. Most respondents received a final diagnosis within a year from noticing first symptoms, but 67% had to visit emergency clinic at least once before diagnosis. 85% had been hospitalized in the last five years. 64% felt that gastroenterologists should ask more probing questions and 54% that they did not get to tell something potentially important to their physician. Most respondents experienced symptoms weekly also in remission. Most had been absent from work due to IBD and 24% had received unfair comments about their work performance. 45% felt that IBD had negatively affected their performance in educational settings.
The results of this survey can be used in defining strategic priorities and planning projects and awareness raising activities. The unmet needs of IBD patients can be better demonstrated and communicated to the public, health service managers and politicians.
No preview · Article · Mar 2014 · Journal of Crohn s and Colitis
[Show abstract][Hide abstract] ABSTRACT: Serum infliximab trough levels correlate with efficacy; dose escalation is often beneficial in patients with Crohn's disease who stop responding to infliximab treatment.
To carry out a post hoc analysis of A Crohn's Disease Clinical Trial Evaluating Infliximab in a New Long-term Treatment Regimen I (ACCENT I) to evaluate the association between serum infliximab trough levels and C-reactive protein (CRP) after 14 weeks of induction treatment with durable sustained long-term response (Crohn's Disease Activity Index decrease ≥70 points and reduction ≥25% from baseline).
ACCENT I was a multicentre, randomised, placebo-controlled study. Week 14 trough levels and CRP percentage decrease from baseline to week 14 were compared between patients with and without durable sustained response through week 54. Sensitivity and specificity were determined to predict durable sustained response. Receiver operating characteristic (ROC) curves identified optimal cut-off points; logistic regression determined ORs.
After induction with 5 mg/kg infliximab, 25% (37/147) and 33% (47/144) of patients sustained week 14 response to infliximab 5 or 10 mg/kg, respectively, administered every 8 weeks without dose escalation, through week 54. Median week 14 trough levels of patients with and without durable sustained response to infliximab 5 mg/kg were 4.0 and 1.9 μg/mL, respectively (p=0.0331). Optimal predictors of durable sustained response to maintenance infliximab 5 mg/kg were week 14 trough level ≥3.5 µg/mL and ≥60% CRP decrease (ORs (95% CI), 3.5 (1.1 to 11.4) and 7.3 (1.4 to 36.7)), respectively, in patients with raised baseline CRP (>8.0 mg/L); area under the ROC curve was 0.75 for both predictors. A ≥3.5 µg/mL week 14 infliximab serum level did not predict durable sustained response to 10 mg/kg maintenance infliximab.
Patients with durable sustained response to maintenance infliximab 5 mg/kg had higher postinduction trough levels than patients without durable sustained response. Serum infliximab trough levels ≥3.5 µg/mL and ≥60% CRP decrease were significantly associated with durable sustained response.
[Show abstract][Hide abstract] ABSTRACT: Crohn's disease (CD) and ulcerative colitis (UC), collectively called inflammatory bowel disease (IBD), are immune-mediated conditions characterized by a chronic inflammation of the gut. Their precise etiology is unknown, although an increased intestinal permeability has been shown to play a central role in the pathogenesis of IBD. The intestinal epithelium provides the largest interface between the external environment and the host, and is thus a crucial regulation site of innate and adaptive immunity. Zonulin is one of the few known physiological mediators of paracellular intestinal permeability. It was found upregulated in different immune diseases like Celiac disease and Type 1 Diabetes (T1D). Recently, human zonulin was identified as prehaptoglobin-2 (pre-HP2) which before only had been regarded as the inactive precursor for HP2. Haptoglobin (HP) is a hemoglobin-binding protein with immunomodulatory properties. Its gene harbors a common polymorphism with 2 different alleles: HP1 and HP2. Allele HP2 and genotype HP22 has been shown to be overrepresented in different immune diseases like Rheumatoid Arthritis (RA), Systemic Lupus Erythematosus (SLE) and T1D, and has also been found to be more frequent in patients with IBD (UC and CD) than in healthy controls. In order to get some clues about the mechanism of action of HP(2) in IBD pathogenesis, we here review the current state of knowledge about zonulin and haptoglobin structure and function, and their plausible role in immune mediated diseases with an emphasis on IBD.
[Show abstract][Hide abstract] ABSTRACT: We present two patients with inflammatory bowel disease who, despite negative tuberculosis screening, developed a de novo tuberculosis infection after the start of anti tumor necrosis factor alpha treatment. We discuss current screening methods and their limitations, the approach after positive screening and the timing to resume anti-TNFα treatment after TB infection. We shortly mention the immune reconstitution inflammatory syndrome (IRIS), described in a few cases after the stop of anti-TNFalpha while treating the tuberculosis infection. We conclude with some remaining questions concerning tuberculosis in IBD patients.
No preview · Article · Nov 2013 · Journal of Crohn s and Colitis