Olivier Dewit

Genome-wide association defines more than 30 distinct susceptibility loci for Crohn's disease

Several risk factors for Crohns disease have been identified in recent genome-wide association studies. To advance gene discovery further, we combined data from three studies on Crohns disease (a total of 3,230 cases and 4,829 controls) and carried out replication in 3,664 independent cases with a mixture of population-based and family-based controls. The results strongly confirm 11 previously reported loci and provide genome-wide significant evidence for 21 additional loci, including the regions containing STAT3, JAK2, ICOSLG, CDKAL1 and ITLN1. The expanded molecular understanding of the basis of this disease offers promise for informed therapeutic development.

Novel Crohn disease locus identified by genome-wide association maps to a gene desert on 5p13.1 and modulates expression of PTGER4

To identify novel susceptibility loci for Crohn disease (CD), we undertook a genome-wide association study with more than 300,000 SNPs characterized in 547 patients and 928 controls. We found three chromosome regions that provided evidence of disease association with p-values between 10−6 and 10−9. Two of these (IL23R on Chromosome 1 and CARD15 on Chromosome 16) correspond to genes previously reported to be associated with CD. In addition, a 250-kb region of Chromosome 5p13.1 was found to contain multiple markers with strongly suggestive evidence of disease association (including four markers with p < 10−7). We replicated the results for 5p13.1 by studying 1,266 additional CD patients, 559 additional controls, and 428 trios. Significant evidence of association (p < 4 × 10−4) was found in case/control comparisons with the replication data, while associated alleles were over-transmitted to affected offspring (p < 0.05), thus confirming that the 5p13.1 locus contributes to CD susceptibility. The CD-associated 250-kb region was saturated with 111 SNP markers. Haplotype analysis supports a complex locus architecture with multiple variants contributing to disease susceptibility. The novel 5p13.1 CD locus is contained within a 1.25-Mb gene desert. We present evidence that disease-associated alleles correlate with quantitative expression levels of the prostaglandin receptor EP4, PTGER4, the gene that resides closest to the associated region. Our results identify a major new susceptibility locus for CD, and suggest that genetic variants associated with disease risk at this locus could modulate cis-acting regulatory elements of PTGER4.

Ciclosporin versus infliximab in patients with severe ulcerative colitis refractory to intravenous steroids: a parallel, open-label randomised controlled trial

BACKGROUND Ciclosporin and infliximab are potential rescue treatments to avoid colectomy in patients with acute severe ulcerative colitis refractory to intravenous corticosteroids. We compared the efficacy and safety of these drugs for this indication. METHODS In this parallel, open-label, randomised controlled trial, patients were aged at least 18 years, had an acute severe flare of ulcerative colitis defined by a Lichtiger score greater than 10 points, and had been given an unsuccessful course of high-dose intravenous steroids. None of the patients had previously received ciclosporin or infliximab. Between June 1, 2007, and Aug 31, 2010, patients at 27 European centres were randomly assigned (via computer-derived permutation tables; 1:1) to receive either intravenous ciclosporin (2 mg/kg per day for 1 week, followed by oral drug until day 98) or infliximab (5 mg/kg on days 0, 14, and 42). In both groups, azathioprine was started at day 7 in patients with a clinical response. Neither patients nor investigators were masked to study treatment. The primary efficacy outcome was treatment failure defined by absence of a clinical response at day 7, a relapse between day 7 and day 98, absence of steroid-free remission at day 98, a severe adverse event leading to treatment interruption, colectomy, or death. Analysis was by intention to treat. This trial is registered with EudraCT (2006-005299-42) and ClinicalTrials.gov (NCT00542152). FINDINGS 115 patients were randomly assigned; 58 patients were allocated to receive ciclosporin and 57 to receive infliximab. Treatment failure occurred in 35 (60%) patients given ciclosporin and 31 (54%) given infliximab (absolute risk difference 6%; 95% CI -7 to 19; p=0·52). Nine (16%) patients in the ciclosporin group and 14 (25%) in the infliximab group had severe adverse events. INTERPRETATION Ciclosporin was not more effective than infliximab in patients with acute severe ulcerative colitis refractory to intravenous steroids. In clinical practice, treatment choice should be guided by physician and centre experience. FUNDING Association François Aupetit, Société Nationale Française de Gastroentérologie, and the International Organization for the study of Inflammatory Bowel Disease.

Resequencing of positional candidates identifies low frequency IL23R coding variants protecting against inflammatory bowel disease

Genome-wide association studies (GWAS) have identified dozens of risk loci for many complex disorders, including Crohns disease. However, common disease-associated SNPs explain at most ∼20% of the genetic variance for Crohns disease. Several factors may account for this unexplained heritability, including rare risk variants not adequately tagged thus far in GWAS. That rare susceptibility variants indeed contribute to variation in multifactorial phenotypes has been demonstrated for colorectal cancer, plasma high-density lipoprotein cholesterol levels, blood pressure, type 1 diabetes, hypertriglyceridemia and, in the case of Crohns disease, for NOD2 (refs. 14,15). Here we describe the use of high-throughput resequencing of DNA pools to search for rare coding variants influencing susceptibility to Crohns disease in 63 GWAS-identified positional candidate genes. We identify low frequency coding variants conferring protection against inflammatory bowel disease in IL23R, but we conclude that rare coding variants in positional candidates do not make a large contribution to inherited predisposition to Crohns disease.

Effect of a retrograde-viewing device on adenoma detection rate during colonoscopy: the TERRACE study

BACKGROUND Although colonoscopy is currently the optimal method for detecting colorectal polyps, some are missed. The Third Eye Retroscope provides an additional retrograde view that may detect polyps behind folds. OBJECTIVE To determine whether the addition of the Third Eye Retroscope to colonoscopy improves the adenoma detection rate. DESIGN Prospective, multicenter, randomized, controlled trial. SETTING Nine European and U.S. centers. PATIENTS Of 448 enrolled subjects, 395 had data for 2 procedures. INTERVENTIONS Subjects underwent same-day tandem examinations with standard colonoscopy (SC) and Third Eye colonoscopy (TEC). Subjects were randomized to SC followed by TEC or TEC followed by SC. MAIN OUTCOME MEASUREMENTS Detection rates for all polyps and adenomas with each method. RESULTS In the per-protocol population, 173 subjects underwent SC and then TEC, and TEC yielded 78 additional polyps (48.8%), including 49 adenomas (45.8%). In 176 subjects undergoing TEC and then SC, SC yielded 31 additional polyps (19.0%), including 26 adenomas (22.6%). Net additional detection rates with TEC were 29.8% for polyps and 23.2% for adenomas. The relative risk of missing with SC compared with TEC was 2.56 for polyps (P < .001) and 1.92 for adenomas (P = .029). Mean withdrawal times for SC and TEC were 7.58 and 9.52 minutes, respectively (P < .001). The median difference in withdrawal times was 1 minute (P < .001). The mean total procedure times for SC and TEC were 16.97 and 20.87 minutes, respectively (P < .001). LIMITATIONS Despite randomization and a large cohort, there was disparity in polyp prevalence between the 2 groups of subjects. CONCLUSION The Third Eye Retroscope increases adenoma detection rate by visualizing areas behind folds. ( CLINICAL TRIAL REGISTRATION NUMBER NCT01044732.).

Endoscopic improvement of mucosal lesions in patients with moderate to severe ileocolonic Crohn's disease following treatment with certolizumab pegol

Objective To evaluate the efficacy of certolizumab pegol (CZP) in improving endoscopic lesions in patients with active ileocolonic Crohns disease (CD). Methods This phase IIIB multicentre open-label clinical trial enrolled 89 adult patients with active endoscopic disease (ulceration in ≥2 intestinal segments with a Crohns Disease Endoscopic Index of Severity (CDEIS) score ≥8 points). Patients received subcutaneous CZP 400 mg at weeks 0, 2 and 4 and every 4 weeks up to week 52. Endoscopic evaluations were performed at weeks 0, 10 and 54. The primary outcome was mean change in CDEIS score at week 10; secondary outcome measures included endoscopic response (decrease in CDEIS score >5 points), remission (CDEIS score <6), complete remission (CDEIS score <3) and mucosal healing (no ulcer) at weeks 10 and 54. Results In the intention-to-treat population (n=89) the mean±SD CDEIS score was 14.5±5.3 at baseline; the mean decrease in CDEIS score at week 10 was 5.7 (95% CI 4.6 to 6.8, p<0.0001). Rates of endoscopic response, endoscopic remission, complete endoscopic remission and mucosal healing at week 10 were 54%, 37%, 10% and 4%, respectively. At week 54 the corresponding rates were 49%, 27%, 14% and 8%, respectively. The safety profile was consistent with that of previous CZP trials. Conclusions Following CZP treatment in patients with active CD, endoscopic lesions were improved as shown by the decrease in mean CDEIS score and by endoscopic response and remission rates. These benefits were achieved as early as week 10 and were generally maintained through week 54. Clinical Trial Registration Number NCT00297648.

Consecutive fecal calprotectin measurements to predict relapse in patients with ulcerative colitis receiving infliximab maintenance therapy

Background: This study examined whether fecal calprotectin can be used in daily practice as a marker to monitor patients with ulcerative colitis (UC) receiving infliximab maintenance therapy. Methods: This prospective multicenter study enrolled adult patients with UC in clinical remission under infliximab maintenance therapy. Fecal calprotectin levels were measured every 4 weeks. Sigmoidoscopies were performed at inclusion and at study end. Relapse was defined as a clinical need for change in treatment or an endoscopic Mayo subscore of ≥2 at week 52. Sustained deep remission was defined as a partial Mayo score <3 at all points and an endoscopic Mayo score 0 at week 52. Results: Full analysis was possible for 87 of 113 included patients with UC (77%). Of these patients, 30 (34.4%) were considered to be in sustained deep remission and 13 (14.9%) to have relapsed. Calprotectin levels in patients with sustained deep remission remained very low (median < 40 mg/kg at all time points). Patients who flared had significantly higher calprotectin levels (median > 300 mg/kg) already 3 months before the flare. Further receiver operator curve analysis suggested that a calprotectin level >300 mg/kg had a reasonable sensitivity (58.3%) and specificity (93.3%) to model flare. Two consecutive calprotectin measurements of >300 mg/kg with 1-month interval were identified as the best predictor of flare (61.5% sensitivity and 100% specificity). Conclusions: Fecal calprotectin can be used in daily practice to monitor patients with UC receiving infliximab maintenance therapy. Two consecutive measurements >300 mg/kg is more specific than a single measurement for predicting relapse.

Association between plasma concentrations of certolizumab pegol and endoscopic outcomes of patients with Crohn's disease

BACKGROUND & AIMS Monitoring plasma concentrations of anti-tumor necrosis factor agents could optimize treatment of patients with Crohns Disease (CD). In a post hoc analysis of data from a clinical trial, we compared the relationship between plasma concentrations of certolizumab pegol (CZP) and endoscopic and clinical responses and remission with CZP therapy in patients with moderate to severe ileocolonic CD. METHODS We analyzed data from the Endoscopic Mucosal Improvement in Patients with Active CD Treated with CZP trial, from 89 adult patients with active endoscopic CD (ulceration in ≥ 2 intestinal segments and CD Endoscopic Index of Severity [CDEIS] scores of ≥ 8 points). Patients received subcutaneous CZP (400 mg) at weeks 0, 2, and 4 and then every 4 weeks until week 52. Endoscopic evaluations were performed at weeks 0, 10, and 54. Blood samples were collected to measure CZP plasma concentrations at weeks 8 and 54. CZP quartiles at weeks 8 (n = 80) and 54 (n = 45) were correlated with endoscopic response (>5-point decrease in CDEIS from baseline) and remission (CDEIS, <6) at weeks 10 and 54, respectively. RESULTS Higher concentrations of CZP at week 8 were associated with endoscopic response (P = .0016) and remission (P = .0302) at week 10 (n = 45). At week 54, the rates of endoscopic remission correlated with plasma concentrations of CZP (P = .0206). There was a significant inverse relationship between plasma concentrations of CZP and baseline levels of C-reactive protein and body weight (P = .0014 and P = .0373, respectively). CONCLUSIONS Endoscopic response and remission are associated with higher plasma concentrations of CZP in patients with moderate to severe ileocolonic CD. These results support the need to consider the pharmacokinetics of anti-tumor necrosis factor agents and therapeutic drug monitoring to optimize treatment. Clinicaltrials.gov Number, NCT00297648.

Fast and sharp decrease in calprotectin predicts remission by infliximab in anti-TNF naïve patients with ulcerative colitis.

AIM To evaluate the effect of infliximab induction therapy on calprotectin levels in patients with ulcerative colitis (UC). PATIENTS AND METHODS In this prospective study 53 patients with active UC from 17 centers were treated with infliximab therapy (5 mg/kg) at baseline, week 2, and week 6. Faecal calprotectin was measured every week. Sigmoidoscopies were performed at baseline, week 6 and week 10. RESULTS Median calprotectin levels decreased from 1260 (IQR 278.5- 3418) at baseline to 72.5 (IQR 18.5 - 463) at week 10 (p<0.001). After 10 weeks, infliximab therapy induced endoscopic remission and a decrease in calprotectin to<50 mg/kg or at least a 80% decrease from baseline level in 58% of patients. A significant and steep decrease of calprotectin levels was seen at week 2 for patients with an endoscopic remission at week 10 as compared to patients who did not show a remission. (p<0.001). At week 10 an excellent correlation was found between endoscopic remission and clinical Mayo score reflected by an AUC of ROC analyses of 0.94 (0.87-1) and with calprotectin measurements (AUC 0.91 (0.81-1)) : all patients with calprotectin levels <50 mg/kg, and a normal clinical Mayo score (=0) were in endoscopic remission. CONCLUSIONS Infliximab induces a fast and significant decrease of faecal calprotectin levels in anti-TNF naïve patients with ulcerative colitis predictive for remission of disease.

Induction therapy with the selective interleukin-23 inhibitor risankizumab in patients with moderate-to-severe Crohn's disease: a randomised, double-blind, placebo-controlled phase 2 study.

BACKGROUND The interleukin-23 pathway is implicated genetically and biologically in the pathogenesis of Crohns disease. We aimed to assess the efficacy and safety of risankizumab (BI 655066, Boehringer Ingelheim, Ingelheim, Germany), a humanised monoclonal antibody targeting the p19 subunit of interleukin-23, in patients with moderately-to-severely active Crohns disease. METHODS In this randomised, double-blind, placebo-controlled phase 2 study, we enrolled patients at 36 referral sites in North America, Europe, and southeast Asia. Eligible patients were aged 18-75 years, with a diagnosis of Crohns disease for at least 3 months, assessed as moderate-to-severe Crohns disease at screening, defined as a Crohns Disease Activity Index (CDAI) of 220-450, with mucosal ulcers in the ileum or colon, or both, and a Crohns Disease Endoscopic Index of Severity (CDEIS) of at least 7 (≥4 for patients with isolated ileitis) on ileocolonoscopy scored by a masked central reader. Patients were randomised 1:1:1 using an interactive response system to a double-blind investigational product, and stratified by previous exposure to TNF antagonists (yes vs no). Patients received intravenous 200 mg risankizumab, 600 mg risankizumab, or placebo, at weeks 0, 4, and 8. The primary outcome was clinical remission (CDAI <150) at week 12 (intention-to-treat population). Safety was assessed in patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT02031276. FINDINGS Between March, 2014, and September, 2015, 213 patients were screened, and 121 patients randomised. At baseline, 113 patients (93%) had been previously treated with at least one tumour necrosis factor (TNF) antagonist (which had failed in 96 [79%]). At week 12, 25 (31%) of 82 risankizumab patients (pooled 41 patients in 200 mg and 41 patients in 600 mg arms) had clinical remission versus six (15%) of 39 placebo patients (difference vs placebo 15·0%, 95% CI 0·1 to 30·1; p=0·0489). Ten (24%) of 41 patients who received 200 mg risankizumab had clinical remission (9·0%, -8·3 to 26·2; p=0·31) and 15 (37%) of 41 who received the 600 mg dose (20·9%, 2·6 to 39·2; p=0·0252). 95 (79%) patients had adverse events (32 in the placebo group, 32 randomised to 200 mg risankizumab, 31 randomised to 600 mg risankizumab); 18 had severe adverse events (nine, six, three); 12 discontinued (six, five, one); 24 had serious adverse events (12, nine, three). The most common adverse event was nausea and most common serious adverse event was worsening of underlying Crohns disease. No deaths occurred. INTERPRETATION In this short-term study, risankizumab was more effective than placebo for inducing clinical remission in patients with active Crohns disease. Therefore, selective blockade of interleukin-23 via inhibition of p19 might be a viable therapeutic approach in Crohns disease. FUNDING Boehringer Ingelheim.