Outcome of Biological Therapies and Small Molecules in Ulcerative Proctitis: A Belgian Multicenter Cohort Study.

BACKGROUND & AIMS: Several advanced therapies (biologic therapies and small molecules) have been approved for the treatment of moderate-to-severe ulcerative colitis. The registration trials for these agents typically excluded patients with isolated proctitis, leaving an evidence gap. We evaluated efficacy and safety of advanced therapies in patients with ulcerative proctitis (UP). METHODS: This multicenter retrospective cohort study included consecutive patients with active UP (Mayo endoscopy subscore of ≥2, rectal inflammation up to 15 cm) initiating advanced therapy, after failing conventional therapy. The primary end point was short-term steroid-free clinical remission (total Mayo score ≤2 with no individual subscore >1). In addition, drug persistence and relapse-free and colectomy-free survival were assessed. Both binary logistic and Cox regression analyses were performed. RESULTS: In total, 167 consecutive patients (52.0% female; median age 41.0 years; 82.0% bionaive) underwent 223 courses of therapy for UP (38 adalimumab, 14 golimumab, 54 infliximab, 9 ustekinumab, 99 vedolizumab, 9 tofacitinib). The primary end point was achieved with 36.3% of the treatment courses, and based on multivariate analysis, more commonly attained in bionaive patients (P = .001), patients treated with vedolizumab (P = .001), patients with moderate endoscopic disease activity (P = .002), and a body mass index <25 kg/m2 (P = .018). Drug persistence was significantly higher in patients treated with vedolizumab (P < .001) and patients with a shorter disease duration (P = .006). No new safety signals were observed. CONCLUSIONS: Advanced therapies are also efficacious and safe in patients with ulcerative colitis limited to the rectum. Therefore, the inclusion of patients with UP in future randomized-controlled trials should be considered.

Early versus Late Use of Vedolizumab in Ulcerative Colitis: Clinical, Endoscopic, and Histological Outcomes.

BACKGROUND AND AIMS: We explored the potential for differential efficacy of vedolizumab between "early" and "late" ulcerative colitis (UC) with evaluation of clinical, endoscopic, and histological endpoints. METHODS: This was a multicentre, multinational open-label study in patients with moderately-to-severely active UC, defining "early" UC by a disease duration <4 years and bio-naïve and "late" UC by a disease duration >4 years and additional exposure to tumour necrosis factor antagonists. Patients received standard treatment with intravenous vedolizumab for 52 weeks (300 mg weeks 0-2-6, every 8 weeks thereafter without escalation). The primary endpoint was corticosteroid-free clinical remission with endoscopic improvement (total Mayo score ≤2 with no subscore >1) at both week 26 and 52. RESULTS: A total of 121 patients were included: in the "early" group 25/59 (42.4%) achieved the primary endpoint versus 19/62 (30.6%) in the "late" group (P = 0.18). There were no significant differences between the two groups in endoscopic improvement (week 26: "early" 32/59 [54.2%] vs. "late" 29/62 [46.8%]; P = 0.412; week 52: 27/59 [45.8%] vs. 25/62 [40.3%]; P = 0.546) or histological remission (Robarts Histopathology Index <3 without neutrophils in the epithelium and lamina propria) (week 26: 24/59 [40.7%] vs. 21/62 [33.9%]; P = 0.439; week 52: 22/59 [37.3%] vs. 22/62 [35.5%]; P = 0.837). CONCLUSIONS: No significant differences in clinical, endoscopic, and histological outcomes were observed between "early" and "late" disease.

Clinical significance and impact of gastric non-Helicobacter pylori Helicobacter species in gastric disease.

BACKGROUND: Gastric non-Helicobacter pylori Helicobacter (NHPH) species naturally associated with animals have been linked with gastric disease in human patients. AIM: The prevalence and clinical significance of zoonotic gastric NHPHs was determined in large and well-defined, H. pylori-negative, gastric patient populations. METHODS: Patients were retrospectively (n = 464) and prospectively (n = 65) included for gastric biopsy collection: chronic gastritis (CG), peptic ulcer disease and gastric MALT lymphoma, without identified aetiology. PCR and sequencing was performed for the detection of gastric Helicobacter species. Retrospectively, asymptomatic gastric bypass patients (n = 38) were included as controls. Prospectively, additional saliva samples and symptom and risk factor questionnaires were collected. In this group, patients with gastric NHPH infection were administered standard H. pylori eradication therapy and underwent follow-up gastroscopy post-therapy. RESULTS: In the retrospective samples, the prevalence of gastric NHPHs was 29.1%, while no gastric NHPHs were detected in control biopsies. In the prospective cohort, a similar proportion tested positive: 27.7% in gastric tissue and 20.6% in saliva. The sensitivity and accuracy for the detection of gastric NHPHs in saliva compared to gastric tissue was 27.8% and 69.8% respectively. Following eradication therapy, clinical remission was registered in 12 of 17 patients, histological remission in seven of nine and eradication in four of eight patients. CONCLUSION: These findings suggest a pathophysiological involvement of NHPHs in gastric disease. Patients presenting with gastric complaints may benefit from routine PCR testing for zoonotic gastric NHPHs.

Lymphoepithelial cysts of the pancreas: case report and review of the literature.

BACKGROUND: Lymphoepithelial cysts (LECs) of the pancreas are a rare type of true pancreatic cysts and represent an estimated 0.5% of all pancreatic cystic lesions. They are benign lesions and have no malignant potential. However, they are hard to differentiate from malignant lesions because their imaging and clinical presentation vary greatly. Seeing as these are benign lesions which are increasingly found incidentally during imaging for other indications, correct diagnosis is important to prevent unnecessary intervention and morbidity. CASE REPORT: We report the case of a 41-year-old female who presented with abdominal discomfort, bloating and dyspepsia. An abdominal computed tomography (CT) showed a large mass in the left fossa. We describe the diagnostic and therapeutic measures taken in this case. METHODS: We reviewed the literature for common features of the LEC. We grouped common imaging and histological features of the LEC of the pancreas to provide easily identifiable characteristics to facilitate diagnosis. For the review, we focused on papers, mostly case reports, presenting these common characteristics. We also reviewed the literature for key topics that should be taken into account when considering therapeutic interventions in a patient with a possible diagnosis of a LEC. CONCLUSION: Cysts of the pancreas are increasingly identified due to widespread use and improved resolution of cross-sectional imaging. To obtain the correct diagnosis, it is sometimes necessary to combine advanced imaging, i.e. CT and MRI-imaging, and endoscopic ultrasound with fine needle aspiration (EUS/FNA), while CA 19-9 also has diagnostic value. We summarize all diagnostic characteristics in a table for ease of use. Furthermore we summarized possible therapeutic interventions.

Uveitis as a window to diagnosis of sarcoidosis - case report and review of the literature.

Sarcoidosis is a multisystem disease of unclear etiology with a variable clinical profile characterized by the presence of non-caseating granuloma in involved organs. The diagnosis is often challenging and based on clinical, radiological and anatomopathological data. Sarcoidosis can be benign and self-limiting, but some cases may follow a chronic, progressive course and result in severe morbidity. The disease has a predilection for the lungs and thoracic lymph nodes but can involve nearly any part of the body, possible more commonly in areas with contact to the external environment, such as the eyes and the skin. This paper is based on a case in which a recurrent uveitis led to the diagnosis of an underlying sarcoidosis.

Standardized approach to idiopathic retroperitoneal fibrosis: a comprehensive review of the literature.

BACKGROUND: Idiopathic retroperitoneal fibrosis (iRPF) is a rare fibro-inflammatory disease, characterized by inflammation of the abdominal aorta and its surrounding structures. The exact pathophysiology remains unclear. Diagnosis is often troublesome due to the non-specific and highly variable clinical presentation. Standardized treatment protocols are lacking. OBJECTIVE: This article presents a review on iRPF, addressing clinical and diagnostic modalities as well as its pathophysiology and the possible inclusion within the IgG4-related disease (IgG4-RD) spectrum. Finally, a diagnostic-therapeutic algorithm for a standardized approach to iRPF is proposed. METHODS: The PubMed Internet database was searched. Articles were selected based on the relevance of abstract, article type and impact of the journal. RESULTS: iRPF and IgG4-RD share a common autoimmune aetiology. Diagnostics are multimodal and based on imaging. Ruling out malignancy should be of primary concern. Complications are mostly of renal or vascular origin due to compression of retroperitoneal structures. Corticosteroids remain the first-line treatment regimen and are mostly successful, but evidence supporting alternative immunosuppressive and anti-inflammatory treatments is growing. Long-term therapy, as well as follow-up, is paramount in this chronic and often relapsing disease.

Pregnancy outcomes in inflammatory bowel disease patients treated with vedolizumab, anti-TNF or conventional therapy: results of the European CONCEIVE study.

BACKGROUND: Women with inflammatory bowel diseases (IBD) often receive biologicals during pregnancy to maintain disease remission. Data on outcome of vedolizumab-exposed pregnancies (VDZE) are sparse. AIMS: To assess pregnancy and child outcomes of VDZE pregnancies and to compare these results to anti-TNF exposed (TNFE) or both immunomodulatory and biologic unexposed (CON IBD) pregnancies. METHODS: A retrospective multicentre case-control observational study was performed. RESULTS: VDZE group included 79 pregnancies in 73 IBD women. The TNFE and CON IBD group included 186 pregnancies (162 live births) in 164 IBD women and 184 pregnancies (163 live births) in 155 IBD women, respectively. At conception, cases more often had active disease ([VDZE: 36% vs TNFE: 17%, P = .002] and [VDZE: 36% vs CON IBD: 24%, P = .063]). No significant difference in miscarriage rates were found between groups (VDZE and TNFE: 16% vs 13%, P = .567; VDZE and CON IBD: 16% vs 10%, P = .216). In live-born infants, median gestational age and birthweight were similar between groups. Median Apgar score at birth was numerically equal. Prematurity was similar in the VDZE group compared to the control groups, even when correcting for disease activity during pregnancy. The frequency of congenital anomalies was comparable between groups as were the percentages of breastfed babies. During the first year of life, no malignancies were reported and infants' infection risk did not significantly differ between groups. CONCLUSION: No new safety signal was detected in VDZE pregnancies although larger, prospective studies are required for confirmation.

Ruminococcus gnavus bacteremia, an uncommon presentation of a common member of the human gut microbiota: case report and literature review.

Case report: We present a case of a 66-year-old female diagnosed with R. gnavus bacteremia associated with fecal peritonits secondary to small-bowel herniation and perforation. Identification  as R. gnavus was delayed because of absence of this species in the MALDI-TOF MS database (Vitek MS, bioMérieux). Identification was provided by 16S rRNA gene sequencing. Review: R. gnavus, a Gram-positive, strictly anaerobic bacterium, is a member of the human gut microbiota. Dysbiosis in the gut microbiota, with increased amounts of R. gnavus, has been described in inflammatory bowel disease. R. gnavus has only been reported occasionally as the cause of infections. Hence the potential pathogenicity is not yet fully recognized, and data regarding the antimicrobial susceptibility profile are rare. Identification of anaerobic bacteria such as R. gnavus is greatly accelerated  as a result of the introduction of MALDI-TOF MS. However, as illustrated in this case report, an extensive and up-to-date MALDI-TOF MS database is necessary for providing an accurate identification.

Impact of first-line infliximab on the pharmacokinetics of second-line vedolizumab in inflammatory bowel diseases.

Background: Very little is known about the impact of the wash-out period on the pharmacokinetics of a second-line biologic. Objective: The objective of this article is to explore the impact of two different wash-out periods on the pharmacokinetics of vedolizumab and infliximab. Methods: Patients switching from infliximab to vedolizumab were retrospectively identified. The population was divided into two groups according to wash-out period: <6 weeks or >6 weeks. Vedolizumab and infliximab trough levels (TLs) were determined and correlated with clinical and biological outcomes. Results: A total of 71 inflammatory bowel disease patients were included. At week 6, in patients previously treated with infliximab, median vedolizumab TLs were 21.9 µg/ml and 24.9 µg/ml for the <6 weeks and >6 weeks wash-out period, respectively (p = 0.31), whereas median residual infliximab TLs were 0.5 µg/ml and 0 µg/ml (p = 0.034). The rate of treatment discontinuation was similar (p = 0.64), and the infectious events were six and two for the <6 weeks and >6 weeks wash-out period, respectively (p = 0.12) by week 30. Conclusions: This study suggests clinicians may not need to be concerned about the impact of wash-out period on the pharmacokinetics of the second-line biologic when switching infliximab to vedolizumab. More data are required on the impact of wash-out period on safety.

Long-term Clinical Effectiveness of Ustekinumab in Patients with Crohn's Disease Who Failed Biologic Therapies: A National Cohort Study.

BACKGROUND: Ustekinumab [UST] was recently approved in Europe for the treatment of moderate to severe Crohn's disease [CD]. Long-term real-world data are currently scarce for CD patients previously exposed to several biologics. METHODS: This is an observational, national, retrospective multicentre study. Patients received intravenous UST ~6 mg/kg at baseline, with 90 mg subcutaneously thereafter every 8 weeks. Response and remission rates were assessed at Weeks 8, 16, and 52. RESULTS: Data from 152 patients were analysed. All patients were exposed to at least one anti-TNFα agent, with 69.7% were exposed to even two anti-TNFα and vedolizumab. After 1 year, 42.1% and 25.7% of patients had experienced clinical response and clinical remission, respectively, and 38.8% and 24.3% had achieved steroid-free clinical response and remission, respectively; 38.8% of patients discontinued therapy during the 12 months of follow-up. Colonic location was predictive of clinical response at 1 year, and low body mass index [BMI] at baseline was a negative predictor of clinical remission. Resolution of arthralgia was associated with clinical response over time. De novo arthralgia was reported by 17.9% of patients at Week 8 and 13.5% of patients at Week 52. No impact of UST on arthralgia was observed in patients with concomitant ankylosing spondylitis [n = 17]. Others adverse events were reported in 7.2% of patients. CONCLUSIONS: This real-world cohort study confirms the effectiveness of UST in CD patients previously exposed to several biologics. Ustekinumab was well tolerated with respect to adverse events. PODCAST: This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast.

Outcome of Pregnancies in Female Patients With Inflammatory Bowel Diseases Treated With Vedolizumab.

BACKGROUND AND AIMS: Vedolizumab is an IgG1 anti-α4ß7 integrin antibody approved for the treatment of inflammatory bowel diseases [IBD], but without clear safety data during conception, pregnancy and nursing. Animal studies showed that mucosal vascular addressin cell adhesion molecule 1 [MAdCAM-1] is expressed by maternal vessels in the placenta and recruits α4ß7-expressing cells that are considered important for maternal/fetal tolerance. Blocking this interaction by vedolizumab might affect this process. We aimed to evaluate pregnancy outcomes in vedolizumab-treated female IBD patients. METHODS: We conducted a retrospective, multicentre Belgian observational study. Details on disease activity, prenatal complications, delivery and neonatal outcome were collected through a case report form. RESULTS: Twenty-four pregnancies were reported. Five women had active disease at conception and one patient flared during pregnancy. There were 23 live births. Complications were observed in 25% of pregnancies [premature rupture of membranes, pre-eclampsia, miscarriage, elective termination and stillbirth] and in 35% of infants [prematurity, intra-uterine growth retardation, small for gestational age and congenital malformations including hip dysplasia, pulmonary valve stenosis and Hirschprung's disease]. Vedolizumab was continued throughout pregnancy in two females and stopped in the 1st and 2nd trimester in five and 16 patients, respectively. For live born children, the median [interquartile range] gestational age, weight and Apgar score 5 min after birth were 39 [37-39.6] weeks, 3270 [3080-3585] grams and 10 [9-10], respectively. CONCLUSIONS: Although several complications were observed, both in mothers and in newborns, no firm conclusions can be drawn. Awaiting prospective and controlled registries, vigilance and strict follow-up of pregnant patients treated with vedolizumab seems mandatory.

Golimumab Dried Blood Spot Analysis (GOUDA): a Prospective Trial Showing Excellent Correlation with Venepuncture Samples and More Detailed Pharmacokinetic Information.

Development of a dried blood spot (DBS) method for golimumab will facilitate sample collection in a study setting and will give a more complete insight in the total drug exposure (area under the curve, AUC). We established a DBS method and assessed its robustness, user-friendliness and clinical usefulness in 10 patients with ulcerative colitis during golimumab induction and maintenance regimens. DBS was obtained through spotting of golimumab spiked in whole citrated blood to a filter paper. Several extraction conditions were evaluated and the selected extraction condition analytically validated. In a clinical setting, DBS and serum samples were taken simultaneously through intensive sampling regimens and a conversion factor was determined. Golimumab concentrations were measured using an in-house-developed ELISA and a CE-marked ELISA kit. User-friendliness was evaluated using a questionnaire. Mucosal healing was evaluated at week 14. A total of 79 matched pairs of serum and DBS sample golimumab concentrations revealed an overall conversion factor of 3.9. DBS golimumab concentrations after conversion correlated strongly with serum golimumab concentrations (ICC = 0.984). During induction, no linear correlation was found between golimumab trough concentration (TC) and AUC (R2 = 0.29). Multiple peaks emerged during drug absorption. Patients who achieved mucosal healing appeared to have less fluctuating TC and a constant AUC over time. Nine out of 10 patients reported DBS sampling as user-friendly. The GOUDA study showed that DBS sampling is a robust and patient-friendly alternative to venous blood collection. DBS sampling may provide better insights into golimumab absorption and exposure. ( ClinicalTrials.gov NCT02910375).

Incidence and Predictors of Success of Adalimumab Dose Escalation and De-escalation in Ulcerative Colitis: a Real-World Belgian Cohort Study.

Background: Adalimumab (ADM) has been shown efficacious in ulcerative colitis (UC). In randomized controlled trials, dose escalation from 40 mg ADM every other week to 40 mg every week was required in 20%-25% of patients within 1 year. Real-life data suggest higher escalation rates. Attempts for dose de-escalation have not been studied yet. We assessed the need for, outcome of, and predictors of dose escalation and de-escalation in a large retrospective cohort of UC patients treated with ADM. Methods: We included 231 consecutive patients from 10 Belgian centers initiating ADM treatment for active UC before September 1, 2015 (follow-up ≥1 year in each patient). We performed detailed chart review to identify variables associated with short-term clinical benefit (based on physician global assessment and absence of rectal bleeding at week 10), success of dose escalation, and dose de-escalation. Backward Cox regression and Wald Logistic regression were used to identify predictive variables. Results: Short-term clinical benefit was achieved in 101 patients (44%) and was less frequent in infliximab failures [37% vs 50%, Odds ratio 0.57 (95% CI 0.34-0.97), P = 0.038]. After a median of 2.8 (1.7-5.1) months, 164 patients (71%) needed ADM discontinuation (n = 35, 15%) or dose escalation (n = 129, 56%). Dose escalation was successful in 77/129 (60%). Dose de-escalation was attempted in 71% (55/77) after a median of 4.3 (2.9-7.2) months and was successful in 80% (43/54). Conclusions: In this cohort, 56% of patients with UC required ADM dose escalation with a 60% success rate. Of note, most patients could be successfully de-escalated later on.

Characteristics of Skin Lesions Associated With Anti-Tumor Necrosis Factor Therapy in Patients With Inflammatory Bowel Disease: A Cohort Study.

BACKGROUND: A subgroup of patients with inflammatory bowel disease (IBD) treated with anti-tumor necrosis factor (TNF) antibodies develop skin lesions, but the lesions and their clinical course are not well-characterized. OBJECTIVE: To describe patients treated with anti-TNF antibodies who did and did not develop skin lesions. DESIGN: Retrospective cohort. SETTING: Single IBD tertiary referral center. PATIENTS: 917 consecutive patients with IBD who initiated anti-TNF therapy. MEASUREMENTS: Skin lesions, patient demographic characteristics, treatments, clinical course, and serologic and genetic markers. RESULTS: During a median follow-up of 3.5 years (interquartile range [IQR], 0.5 to 7.4 years), skin lesions associated with the use of anti-TNF therapy developed in 264 of 917 (29%) patients (psoriasiform eczema, 30.6%; eczema, 23.5%; xerosis cutis, 10.6%; palmoplantar pustulosis, 5.3%; psoriasis, 3.8%; other, 26.1%). Lesions typically developed at flexural regions, genitalia, and the scalp, especially the psoriasiform lesions. Thirty-one percent of women and 26% of men developed lesions. Median cumulative doses (2864 mg/y [IQR, 2203 to 3819 mg/y] and 2927 mg/y [IQR, 2377 to 3667 mg/y]) and trough levels (4.2 µg/mL [IQR, 2.6 to 5.8 µg/mL] and 4.0 µg/mL [IQR, 1.6 to 5.9 µg/mL]) of infliximab were similar in patients with and without lesions. All but 28 patients (11%) were successfully managed without needing to stop therapy because of lesions. LIMITATION: Retrospective nature and no matched control group of patients not receiving anti-TNF therapy. CONCLUSION: Skin lesions occur frequently in association with anti-TNF therapy but rarely require discontinuation of therapy. Close surveillance and early referral to a dedicated dermatologist are recommended. PRIMARY FUNDING SOURCE: Research Foundation Flanders (FWO), Belgium; Geconcerteerde Onderzoekacties of KU Leuven; and Janssen Biologics.

The Occurrence of Thrombosis in Inflammatory Bowel Disease Is Reflected in the Clot Lysis Profile.

BACKGROUND: The occurrence of thromboembolic events (TE) is an important extraintestinal manifestation in patients with inflammatory bowel disease (IBD). The aim of this study was to compare fibrinolysis and clot lysis parameters between (1) patients with IBD and healthy controls and (2) patients with IBD with TE (IBD + TE) and without TE (IBD - TE). METHODS: One hundred thirteen healthy controls and 202 patients with IBD, of which 84 patients with IBD + TE and 118 patients with IBD - TE, were included in this case-control study. Three clot lysis parameters (area under the curve, 50% clot lysis time, and amplitude) were determined using a clot lysis assay. Plasminogen activator inhibitor 1 (PAI-1) and thrombin activatable fibrinolysis inhibitor concentrations were determined by enzyme-linked immunosorbent assay. RESULTS: PAI-1 antigen, active PAI-1, and intact thrombin activatable fibrinolysis inhibitor concentrations, as well as 50% clot lysis time and area under the curve, were significantly associated with the presence of IBD (all P < 0.05). The median time between TE and plasma collection was 5.0 (1.8-11.0) years. Comparing IBD + TE versus IBD - TE, active to total PAI-1 ratio (0.36 [0.24-0.61] versus 0.24 [0.13-0.40]), area under the curve (31 [24-49] versus 22 [13-31]), 50% clot lysis time (110 [64-132] versus 95 [70-126] minutes), and amplitude (0.295 [0.222-0.436] versus 0.241 [0.168-0.308]) were significantly higher in IBD + TE (all P <0.05) and remained higher after adjustment for age, gender, C-reactive protein, type of disease, presence of comorbidities, and disease activity. CONCLUSIONS: Patients with IBD have an altered clot lysis profile compared with healthy controls. Clot lysis parameters differ significantly between patients with IBD with and without a history of TE and should be included in the risk assessment.

Levels of C-reactive protein are associated with response to infliximab therapy in patients with Crohn's disease.

BACKGROUND & AIMS: Infliximab is an antibody against tumor necrosis factor-α that is used to treat patients with moderate to severe Crohn's disease (CD). C-reactive protein (CRP) is a marker used to identify and follow individuals with CD. We analyzed changes in levels of CRP in a large cohort of patients with CD undergoing treatment with infliximab. METHODS: Serial levels of CRP were analyzed in 718 CD patients. Blood was collected before each infusion; a total of 8845 CRP levels were available for analysis. The correlations between CRP levels and need for dose adjustment, outcomes, and mucosal healing (based on endoscopic analysis of 253 patients) were evaluated. Therapy adjustment was considered successful if therapy continued without need for change. Subgroup analysis was performed by using data from 268 patients who received 8 weeks of maintenance therapy. RESULTS: More patients with high baseline levels of CRP responded to infliximab than patients with normal levels (90.8% vs 82.6%; P = .014). Early normalization of CRP levels correlated with sustained long-term response (P < .001). CRP levels remained significantly higher among patients who lost their response to infliximab, compared with those with a sustained response (P = .001). At time of loss of response, CRP levels were significantly increased (median, 11.2 mg/L) and did not return to baseline levels (median, 18.2 mg/L; P = .039). CRP correlated with mucosal healing (P = .033). CONCLUSIONS: CRP is a good marker of disease activity in patients treated with infliximab. Increased levels of CRP indicate mucosal inflammation and a likelihood of clinical relapse.

Molecular reclassification of Crohn's disease by cluster analysis of genetic variants.

BACKGROUND: Crohn's Disease (CD) has a heterogeneous presentation, and is typically classified according to extent and location of disease. The genetic susceptibility to CD is well known and genome-wide association scans (GWAS) and meta-analysis thereof have identified over 30 susceptibility loci. Except for the association between ileal CD and NOD2 mutations, efforts in trying to link CD genetics to clinical subphenotypes have not been very successful. We hypothesized that the large number of confirmed genetic variants enables (better) classification of CD patients. METHODOLOGY/PRINCIPAL FINDINGS: To look for genetic-based subgroups, genotyping results of 46 SNPs identified from CD GWAS were analyzed by Latent Class Analysis (LCA) in CD patients and in healthy controls. Six genetic-based subgroups were identified in CD patients, which were significantly different from the five subgroups found in healthy controls. The identified CD-specific clusters are therefore likely to contribute to disease behavior. We then looked at whether we could relate the genetic-based subgroups to the currently used clinical parameters. Although modest differences in prevalence of disease location and behavior could be observed among the CD clusters, Random Forest analysis showed that patients could not be allocated to one of the 6 genetic-based subgroups based on the typically used clinical parameters alone. This points to a poor relationship between the genetic-based subgroups and the used clinical subphenotypes. CONCLUSIONS/SIGNIFICANCE: This approach serves as a first step to reclassify Crohn's disease. The used technique can be applied to other common complex diseases as well, and will help to complete patient characterization, in order to evolve towards personalized medicine.