The Influence of Subclinical Active Inflammation on IFX Pharmacokinetic Modeling and Disease Progression Assessment: Findings from a Prospective Real-World Study in Inflammatory Bowel Disease Patients.

BACKGROUND AND AIMS: Effective management of inflammatory bowel disease (IBD) relies on a comprehensive understanding of infliximab (IFX) pharmacokinetics (PK). This study's primary goal was to develop a robust PK model, identifying key covariates influencing IFX clearance (CL), while concurrently evaluating the risk of disease progression during the maintenance phase of IBD treatment. METHODS: The multicenter, prospective, real-world DIRECT study was conducted in several care centers, which included 369 IBD patients in the maintenance phase of IFX therapy. A two-compartment population PK model was used to determine IFX CL and covariates. Logistic and Cox regressions were applied to elucidate the associations between disease progression and covariates embedded in the PK model. RESULTS: The PK model included the contributions of weight, albumin, antidrug antibody (ADA), and fecal calprotectin (FC). On average, higher ADA, FC concentration and weight, and lower albumin concentration resulted in higher IFX CL. In the multivariate regression analyses, FC levels influenced the odds of disease progression in the majority of its definitions, when adjusted for several confounding factors. Additionally, alongside FC, both IFX and CL demonstrated a significant impact on the temporal aspect of disease progression. CONCLUSION: In this 2-year real-world study, readily available clinical covariates, notably FC, significantly impacted IFX availability in IBD patients. We demonstrated that subclinical active inflammation, as mirrored by FC or CRP, substantially influenced IFX clearance. Importantly, FC emerged as a pivotal determinant, not only of IFX pharmacokinetics but also of disease progression. These findings underscore the need to integrate FC into forthcoming IFX pharmacokinetic models, amplifying its clinical significance.

Accuracy of Gastrointestinal Ultrasound and Calprotectin in the Assessment of Inflammation and its Location in Patients with an Ileoanal Pouch.

BACKGROUND AND AIMS: In symptomatic patients with ileoanal pouches, pouchoscopy is needed for accurate diagnosis but is invasive. We aimed to assess the utility of non-invasive gastrointestinal ultrasound and faecal calprotectin in ileoanal pouch patients. METHODS: Patients with an ileoanal pouch were consecutively enrolled in this cross-sectional study from clinics in Victoria, Australia. The pouchitis disease activity index was used as a reference standard. Video-recorded pouchoscopies were reviewed by three gastroenterologists. Pouch, pre-pouch, and cuff biopsies were reviewed by a single pathologist. Ultrasound was performed by a single gastroenterologist transabdominally and transperineally. Faecal calprotectin was measured from morning stool samples. All examiners were blinded to patients' clinical history. RESULTS: A total of 44 participants had a pouchoscopy, of whom 43 had a faecal calprotectin test and 42 had an ultrasound; 17 had pouchitis, 15 had pre-pouch ileitis, and 16 had cuffitis. Pouch wall thickness of <3 mm was 88% sensitive in excluding pouchitis, and pouch wall thickness of ≥4 mm was 87% specific in diagnosing pouchitis. Transabdominal ultrasound had good utility [area under the curve: 0.78] in diagnosing moderate-severe pre-pouch ileitis. Transperineal ultrasound had good utility for the diagnosis of pouchitis [area under the curve: 0.79]. Faecal calprotectin differentiated inflammatory from non-inflammatory pouch disorders, such as irritable pouch syndrome, with an area under the curve of 0.90. Faecal calprotectin <100 µg/g ruled out inflammatory pouch disorders with a sensitivity of 94%. CONCLUSIONS: Faecal calprotectin and ultrasound are accurate and complementary tests to diagnose and localise inflammation of the ileoanal pouch. Prospective studies are needed to validate proposed sonographic indices and calprotectin levels.

The Reliability and Accuracy of Endoscopic Items and Scores Used in the Assessment of the Ileoanal Pouch and Cuff.

BACKGROUND AND AIMS: Currently used endoscopic items for the assessment of pouchitis and cuffitis have deficiencies in reliability and validation. We assessed the reliability and accuracy of new endoscopic items for pouchitis and of the Ulcerative Colitis Endoscopic Index of Severity [UCEIS] for cuffitis. METHODS: Three new endoscopic items were assessed and included in the Monash pouchitis endoscopic subscore: bleeding [absent/contact/spontaneous]; erosions [absent/<10/≥10]; and ulceration [absent/<10%/≥10%]. Three raters evaluated 44 pouchoscopy videos in duplicates, in random order. Intra- and inter-rater reliability of all endoscopic items and UCEIS were assessed. Clinical and histological pouchitis disease activity index [PDAI] subscores were also assessed and faecal calprotectin was measured. RESULTS: All three Monash endoscopic items had substantial intra-rater reliability with intraclass correlation coefficients [ICCs] >0.61 [95% CI >0.61], compared with only ulcers from the currently used PDAI endoscopic subscore, but inter-rater reliability was only substantial for ulceration and no better than those of the currently used endoscopic items. The Monash endoscopic subscore had a strong positive correlation with the reference standard global endoscopic lesion severity r = 0.80 [95% CI 0.80-0.80] and the reference standard PDAI endoscopic subscore r = 0.70 [95% CI 0.67-0.73], which was higher than the correlation observed for the currently used PDAI endoscopic subscore. The UCEIS had substantial intra-rater reliability, but only fair inter-rater reliability and poor diagnostic performance for cuffitis. CONCLUSIONS: The Monash endoscopic items, and endoscopic subscore they generate, have enhanced overall performance compared with the currently used PDAI items and subscore. Further validation and responsiveness to change in disease state are indicated.

A Microsimulation Model to Determine the Cost-Effectiveness of Treat-to-Target Strategies for Crohn's Disease.

INTRODUCTION: Cost-effectiveness of biomarker- vs endoscopy-based treat-to-target monitoring in Crohn's disease (CD) is unknown. METHODS: A microsimulation model for CD was built to simulate biomarker (fecal calprotectin) vs endoscopy-based monitoring in a treat-to-target fashion. Published literature in combination with patient-level data from phase 3 clinical trials and population estimates for therapeutic drug monitoring were used to generate transition probabilities, costs, and utilities. Tracker variables were used to modify downstream probabilities and outcomes based on previous exposures, response patterns, and disease-related complications or surgery history. The primary outcome was cost-effectiveness over a 5-year horizon at a willingness-to-pay threshold of $100,000/quality-adjusted life-year. Probabilistic sensitivity analyses in addition to multiple 1-, 2-, and 3-way microsimulation sensitivity analyses were performed. RESULTS: In the base-case model, the endoscopy-based monitoring strategy dominated the biomarker-based monitoring strategy over a 5-year horizon. Over shorter periods of observation, the biomarker-based monitoring strategy became progressively more cost-effective, with cost-effectiveness achieved for this strategy over a 1-year horizon. Therapeutic drug monitoring did not influence short-term cost-effectiveness of biomarker-based monitoring. Once in endoscopic remission, continued biomarker-based vs endoscopy-based monitoring was more cost-effective. A hybrid biomarker-endoscopy-based monitoring strategy dominated the endoscopy-based monitoring strategy over a 5-year horizon. The strongest determinants for cost-effectiveness were cost of colonoscopy and diagnostic performance of fecal calprotectin. DISCUSSION: The most cost-effective approach for treat-to-target monitoring in CD is up-front biomarker-based monitoring followed by endoscopy-based monitoring if not in endoscopic remission by 1 year and then returning to biomarker-based monitoring once in endoscopic remission.

Long-term Safety and Efficacy of the Anti-MAdCAM-1 Monoclonal Antibody Ontamalimab [SHP647] for the Treatment of Ulcerative Colitis: The Open-label Study TURANDOT II.

BACKGROUND AND AIMS: Ontamalimab, a fully-human monoclonal antibody targeting MAdCAM-1, induced remission in patients with moderate-to-severe ulcerative colitis [UC] in the TURANDOT study. We aimed to assess long-term safety, tolerability, and efficacy of ontamalimab in TURANDOT II. METHODS: TURANDOT II was a phase 2, multicentre, open-label [OL] study in patients with moderate-to-severe UC who completed TURANDOT on placebo or ontamalimab (NCT01771809). Patients were randomised to 75 mg or 225 mg ontamalimab every 4 weeks for 72 weeks [OL1]. The dosage could be increased to 225 mg from Week 8 at the investigator's discretion. All patients then received 75 mg every 4 weeks for 72 weeks [OL2], followed by 6-month safety follow-up. The primary objective was safety, measured by adverse events [AEs], serious AEs [SAEs], and AEs leading to withdrawal. Mucosal healing [MH; centrally read endoscopy] was assessed. RESULTS: Of 330 patients, 180 completed OL1; 94 escalated to 225 mg; 127 completed OL2. Overall, 36.1% experienced drug-related AEs. The most common SAE [10.0%] was worsening/ongoing UC; 5.5% of patients had serious infections, the most common being gastroenteritis [0.9%]. One death and four cancers [all unrelated to ontamalimab] occurred. No PML [progressive multifocal leukoencephalopathy]/lymphoproliferative disorders occurred. Geometric mean high-sensitivity C-reactive protein [hsCRP] and faecal calprotectin decreased across OL1 in both dose groups. The proportion of patients assigned to placebo in TURANDOT achieving MH increased from 8.8% [6/68] at baseline to 35.3% at Week 16 [24/68; non-responder imputation]. The corresponding increase in the ontamalimab group was from 23.3% [61/262] to 26.7% [70/262]. CONCLUSIONS: Ontamalimab was well tolerated up to 144 weeks in patients with moderate-to-severe UC, with good safety and efficacy.

Non-invasive Ultrasonographic Score for Assessment of the Severity of Inflammatory Bowel Disease.

Intestinal ultrasound and shear wave elastography have gained increasing interest because of their promising results in the assessment of inflammatory bowel disease. The aim of this study was to find an ultrasonographic score to replace invasive endoscopic procedures for the management of these patients. The score includes ultrasound parameters that correlate well with clinical severity scales and inflammatory markers: bowel wall thickness, the Limberg score, disease extension and acoustic radiation force impulse measurements. The score proved to be well correlated with the Harvey Bradshaw Index, the Mayo score, C-reactive protein and fecal calprotectin. For Crohn's disease, a cutoff value of 8 points could identify active disease with 81.81% sensitivity and 83% specificity, while for ulcerative colitis, a cutoff value of 7 points could discriminate between remission and relapse with 86.85% sensitivity and 94% specificity. In conclusion, our ultrasonographic score can differentiate relapse from remission in inflammatory bowel disease.

Comparison of 18F-FDG PET-MR and fecal biomarkers in the assessment of disease activity in patients with ulcerative colitis.

OBJECTIVE: To compare the diagnostic performance of fecal biomarkers and 18F-fludeoxyglucose (18F-FDG) positron emmision tomography-MR (PET-MR) in the assessment of disease activity in patients with ulcerative colitis. METHODS: This study was conducted under the framework of a single-center clinical trial (clinicaltrials.gov [NCT03781284]). N = 50 participants were enrolled. Fecal samples were collected before bowel preparation. All patients underwent whole-body 18F-FDG PET-MR followed by ileocolonoscopy within 24 h. Diagnostic performance of five fecal biomarkers (calprotectin, lactoferrin, polymorphonuclear leukocyte elastase, S100A12 and eosinophil-derived neurotoxin), MR morphological parameters (MRmorph), diffusion-weighted imaging and PET in detecting active disease determined by Rachmilewitz endoscopic activity index (EAI) were evaluated and compared with each other. Correlations between fecal biomarkers, PET and endoscopy were calculated. RESULTS: According to EAI, n = 38 patients presented with endoscopically active disease (16 mild, 19 moderate and 3 severe). All five biomarkers, PET and MRmorph could differentiate endoscopically active disease from endoscopic remission without significant difference regarding their operating characteristics (accuracies between 0.673 for calprotectin and 0.898 for lactoferrin). In predicting endoscopically moderate to severe disease, PET showed the highest diagnostic performance (accuracy = 0.857) compared to calprotectin and lactoferrin (accuracy = 0.633 and 0.735). PET had also the strongest correlation with endoscopy (ρ = 0.685, p < 0.001), while within fecal biomarkers the levels of lactoferrin and eosinophil-derived neurotoxin correlated significantly with EAI (ρ = 0.423 and 0.528, both p < 0.05). CONCLUSION: Both fecal biomarkers and PET-MR were excellent non-invasive diagnostic tools in the assessment of disease activity in ulcerative colitis. ADVANCES IN KNOWLEDGE: Both fecal biomarkers and PET-MR parameters are able to predict endoscopically active disease with comparable diagnostic performance. PET had the highest correlation with endoscopy and outperformed fecal biomarkers in differentiating moderate to severe from mild disease.

Development and Validation of the Mucosal Inflammation Noninvasive Index For Pediatric Crohn's Disease.

BACKGROUND & AIMS: Mucosal healing (MH) has become a goal of therapy for Crohn's disease (CD), but frequent endoscopies are not feasible. We aimed to develop and validate a non-invasive index to assess mucosal inflammation in children with CD. METHODS: We collected data from the multi-center prospective ImageKids study, in which children with CD underwent ileocolonoscopy with magnetic resonance enterography. We investigated the association of pediatric CD activity index (PCDAI) items and laboratory test results with the simple endoscopic score for CD (SESCD). We used these data in a blended mathematical judgmental clinimetric approach to develop a weighted categorized index to identify children with CD who have MH, which we called the MINI index. We validated the index using data from 3 independent patient cohorts. The derivation and validation cohorts included 154 and 168 children, respectively (age 14.1 ± 2.5 years and 14.2 ± 3.9 years), of whom 16% and 36% had MH (defined as SESCD<3). RESULTS: In multivariable models, the stooling item of the PCDAI, erythrocyte sedimentation rate, and level of fecal calprotectin were associated with SESCD (all P < .05). We added data on level of C-reactive protein to develop the MINI index. MINI scores below 8 identified children with MH with 88% sensitivity and 85% specificity in the derivation cohort and with 84% sensitivity and 87% specificity in the validation cohorts. Ninety percent of the patients in the validation cohort with scores of 8 or more had active mucosal inflammation, yet 78% of patients with scores below 8 had MH. Scores below 6 increase the positive predictive value to 86%. CONCLUSIONS: We developed an index to non-invasively assess mucosal inflammation in children with CD. This index, identifies children with MH with high sensitivity and specificity. The added benefit of MINI over measurement of fecal calprotectin was small but significant, especially for patients with concentrations of fecal calprotectin from 100 to 599 µg/g. ClinicalTrials.gov no: NCT01881490.

Disease monitoring strategies in inflammatory bowel diseases: What do we mean by "tight control"?

In recent years, there has been a critical change in treatment paradigms in inflammatory bowel diseases (IBD) triggered by the arrival of new effective treatments aiming to prevent disease progression, bowel damage and disability. The insufficiency of symptomatic disease control and the well-known discordance between symptoms and objective measures of disease activity lead to the need of reviewing conventional treatment algorithms and developing new concepts of optimal therapeutic strategy. The treat-to-target strategies, defined by the selecting therapeutic targets in inflammatory bowel disease consensus recommendation, move away from only symptomatic disease control and support targeting composite therapeutic endpoints (clinical and endoscopical remission) and timely assessment. Emerging data suggest that early therapy using a treat-to-target approach and an algorithmic therapy escalation using regular disease monitoring by clinical and biochemical markers (fecal calprotectin and C-reactive protein) leads to improved outcomes. This review aims to present the emerging strategies and supporting evidence in the current therapeutic paradigm of IBD including the concepts of "early intervention", "treat-to-target" and "tight control" strategies. We also discuss the real-word experience and applicability of these new strategies and give an overview on the future perspectives and areas in need of further research and potential improvement regarding treatment targets and ("tight") disease monitoring strategies.

Cost-effectiveness of faecal calprotectin used in primary care in the diagnosis of inflammatory bowel disease.

OBJECTIVE: Inflammatory bowel disease (IBD) is a chronic, autoimmune, gastrointestinal disorder. Canada has one of the highest prevalence and incidence rates of IBD in the world. Diagnosis is challenging due to the similarity of symptoms to functional gastrointestinal disorders. Faecalcalprotectin (FC) is a biomarker for active mucosal inflammation and has proven effective in the diagnosis of IBD. Our study objective was to assess the cost-effectiveness of adding an FC test compared with standard practice (blood test) in primary care among adult patients presenting with gastrointestinal symptoms. DESIGN: We constructed a decision analytic tree with a 1-year time horizon. The cut-off level of 100 µg/g was used for FC testing. Probabilistic analyses were conducted for the base case and all scenarios. SETTING: Canadian health sector perspective. POPULATION: A hypothetical cohort of adult patients presenting with gastrointestinal symptoms in the primary care setting. INTERVENTIONS: FC test compared with blood test. MAIN OUTCOME MEASURES: Costs, quality-adjusted life years (QALYs), incremental cost-effectiveness ratio (ICER) of FC test expressed as cost per QALY gained compared with blood test and time to IBD diagnosis. RESULTS: FC testing is expected to cost more ($C295.1 vs $C273.9) than standard practice but yield little higher QALY (0.751vs0.750). The ICER of FC test was $C20 323 per QALY. Probabilistic analysis demonstrated that at a willingness-to-pay threshold of $C50 000 per QALY, there was 81.3% probability of FC test being cost-effective. The use of FC test in primary care reduced the time to IBD diagnosis by 40.0 days (95% CI 16.3 to 65.3 days), compared with blood testing alone. CONCLUSIONS: Based on this analysis of short-term outcomes, screening adult patients in primary care using FC test at a cut-off level of 100 µg/g is expected to be cost-effective in Canada.

Faecal Calprotectin Is a Very Reliable Tool to Predict and Monitor the Risk of Relapse After Therapeutic De-escalation in Patients With Inflammatory Bowel Diseases.

AIMS: To assess faecal calprotectin [Fcal] levels before and after therapeutic de-escalation, to predict clinical relapse in patients with inflammatory bowel disease [IBD]. METHODS: From a prospectively maintained database, we enrolled 160 IBD patients [112 Crohn's disease/48 ulcerative colitis] in clinical remission, with Fcal measured within 8 weeks before therapeutic de-escalation. Clinical relapse was defined using the Harvey-Bradshaw index or Simple Clinical Colitis Activity Index. RESULTS: Using a receiver operating characteristic [ROC] curve, Fcal >100 µg/g was the best threshold to predict clinical relapse after therapeutic de-escalation (area under the curve [AUC] = 0.84). In multivariate analysis, clinical remission >6 months before therapeutic de-escalation (hazard ratio [HR] = 0.57 [0.33-0.99]; p = 0.044) was associated with decreased risk of relapse, whereas current steroid medication ( = 1.67[1.00-2.79]; p <0.0001) was a risk factor. Fcal >100 µg/g was predictive of clinical relapse (HR = 3.96 [2.47-6.35]; p < 0.0001) in the whole cohort but also in patients receiving anti-tumour necrosis factor [TNF] agents [n = 85 patients; p <0.0001], anti-integrins [n = 32; p = 0.003], or no biologics [n = 43; p = 0.049], or attempting to discontinue steroids [n = 37; p = 0.001]. One patient [1/98] and seven patients [7/88, 8.0%] with baseline Fcal <100 µg/g relapsed within 3 months and 6 months after therapeutic de-escalation, respectively. A total of 74 Fcal measurements were performed in 52 patients after therapeutic de-escalation. Monitoring Fcal >200 µg/g [ROC curve with AUC = 0.96] was highly predictive of clinical relapse in multivariate analysis ([HR = 31.8 [3.5-289.4], p = 0.002). Only two relapses [2/45, 4.4%] occurred within 6 months while Fcal <200 µg/g. CONCLUSIONS: Fcal level is highly accurate to predict and monitor the risk of relapse after therapeutic de-escalation in IBD patients and could be used in daily practice.

Comparison of different histological indexes in the assessment of UC activity and their accuracy regarding endoscopic outcomes and faecal calprotectin levels.

OBJECTIVE: Histological remission is being increasingly acknowledged as a therapeutic endpoint in patients with UC. The work hereafter described aimed to evaluate the concordance between three histological classification systems-Geboes Score (GS), Nancy Index (NI) and RobartsHistopathologyIndex (RHI), as well as to evaluate their association with the endoscopic outcomes and the faecal calprotectin (FC) levels. DESIGN: Biopsy samples from 377 patients with UC were blindly evaluated using GS, NI and RHI. The results were compared with the patients' Mayo Endoscopic Score and FC levels. RESULT: GS, NI and RHI have a good concordance concerning the distinction between patients in histological remission or activity. RHI was particularly close to NI, with 100% of all patients classified as being in remission with NI being identified as such with RHI and 100% of all patients classified as having activity with RHI being identified as such with NI. These scores could also predict the Mayo Endoscopic Score and the FC levels, with their sensitivity and specificity levels depending on the chosen cut-offs. Moreover, higher FC levels were statistically associated with the presence of neutrophils in the epithelium, as well as with ulceration or erosion of the intestinal mucosa. CONCLUSIONS: GS, NI and RHI histopathological scoring systems are comparable in what concerns patients' stratification into histological remission/activity. Additionally, FC levels are increased when neutrophils are present in the epithelium and the intestinal mucosa has erosions or ulcers. The presence of neutrophils in the epithelium is, indeed, the main marker of histological activity.

Faecal calprotectin delivers on convenience, cost reduction and clinical decision-making in inflammatory bowel disease: a real-world cohort study.

BACKGROUND: Faecal calprotectin (FC) is an accurate biomarker of disease activity in inflammatory bowel disease (IBD), yet the cost/resource implications of incorporating FC into 'real-world' practice remain uncertain. AIM: To evaluate the utility of FC in clinical decision-making and on healthcare costs in IBD. METHODS: Retrospective data, including colonoscopy/other investigations, medication, admission and surgical data, were collected from hospital records and compared between two groups: pre-FC historical cohort (2005-2009) where colonoscopy was used to assess IBD activity versus the cohort where FC was used first instead (2010-2014). Post-test costs were also compared. RESULTS: A total of 357 FC tests (246 patients, 2010-2014) and 450 colonoscopies (268 patients, 2005-2009) were performed. On subsequent review, both FC and colonoscopy (in their respective cohorts) were associated with changes in management in 50.7 versus 56.2% (P = 0.14), respectively, with similar proportions of subsequent IBD-related investigations within 6 months (21.8 vs 21.9%, P = 1.0). Prior to FC availability (2005-2009), a colonoscopy for disease reassessment cost AU$606 578 (cost per patient-year $1887.34) versus AU$282 048 (cost per patient-year $968.60) when FC ± colonoscopy was used (2010-2014). Within the FC cohort, 73.6% did not proceed to colonoscopy within 6 months post-FC, and 60.6% had not undergone colonoscopy post-FC by the end of follow up (median 1.8 years (0.1, 4.6) post-FC). Those with FC ≥ 250 were scoped earlier than those with FC < 100 µg/mL (median 0.49 vs 1.0 years, P = 0.03). CONCLUSION: Introduction of FC into routine IBD care aided changes in clinical management in a similar proportion, yet at potentially half the total cost, compared to a historical colonoscopy-only cohort at the same centre.

Role of fecal calprotectin in the assessment of intestinal inflammation in children with familial Mediterranean fever.

AIM: Familial Mediterranean fever (FMF) is the most common auto-inflammatory disease with recurrent fever and serositis episodes. In recent years, some cases with FMF were reported with gastrointestinal involvement without amyloidosis, vasculitis and inflammatory bowel disease (IBD). It is not yet known whether gastrointestinal involvement is a part of the disease or not. The aim of this study is to investigate the frequency of intestinal inflammation by using a noninvasive method, fecal calprotectin measurement, in pediatric FMF patients. METHOD: Sixty-five FMF patients, 30 healthy controls and 11 patients with acute ulcerative colitis were included in the study. A standard survey inquiring gastrointestinal and other clinical symptoms was completed. The medications, MEFV mutations, whole blood count and C-reactive protein levels were recorded. Fecal calprotectin was studied with the enzyme-linked immunosorbent assay method from the feces samples of the all subjects. RESULTS: None of the FMF patients had clinical signs of IBD. Fecal calprotectin levels of the FMF patients were found to be significantly higher than the healthy controls (174.8 ± 150.8 vs 52.9 ± 36.5, p < 0.001). Fecal calprotectin levels of the ulcerative colitis patients were significantly higher than the FMF patients (523.5 ± 183 vs 174.8 ± 150.8, p = 0.001). There was a correlation between fecal calprotectin levels and neutrophil/lymphocyte ratio (r = 0.324, p = 0.009). CONCLUSION: Our results supported subclinical intestinal inflammation in pediatric FMF patients. Further studies are needed to clarify the reason for intestinal inflammation in FMF patients.

Success and safety of high infliximab trough levels in inflammatory bowel disease.

OBJECTIVE: A prospective trial suggests target infliximab trough levels of 3-7 µg/mL, yet data on additional therapeutic benefits and safety of higher trough levels are scarce. AIM: To explore whether high infliximab trough levels (≥7 µg/mL) are more effective and still safe. MATERIAL AND METHODS: In this cohort study of 183 patients (109 Crohn's disease and 74 ulcerative colitis) on infliximab maintenance treatment at a tertiary referral center we correlated fecal calprotectin and C-reactive protein to trough levels (426 samples) at different time points during treatment. Rates of infections were compared in quadrimesters (four-month periods) with high trough levels to quadrimesters with trough levels <7 µg/mL during 420 patient-years. RESULTS: Fecal calprotectin and C-reactive protein (median [interquartile range]) were lower in patients with high trough levels (fecal calprotectin 66 mg/kg [30-257]; C-reactive protein 3 mg/L [3-3]) compared to trough levels below 7 µg/mL (fecal calprotectin 155 mg/kg [72-474]; C-reactive protein 3 mg/L [3-14.5]) (p < .001). High trough levels were superior also after excluding samples with trough levels <3 µg/mL from analysis. No differences in rates of infections were observed in quadrimesters with high trough levels (16/129 [12.4%]) compared to quadrimesters with trough levels <7 µg/mL (32/344 [9.3%]) (p = .32). Maintaining high trough levels resulted in 32% (interquartile range: 2-54%) increase of infliximab consumption. CONCLUSION: High infliximab trough levels provide better control of inflammation in inflammatory bowel disease without increasing the risk of infection.

Fecal Immunochemical Test and Fecal Calprotectin Results Show Different Profiles in Disease Monitoring for Ulcerative Colitis.

BACKGROUND/AIMS: Both fecal immunochemical test (FIT) and fecal calprotectin (Fcal) results are useful biomarkers for ulcerative colitis (UC). However, the situations in which each marker should be used are largely unknown. METHODS: A total of 110 colonoscopy intervals of UC patients were assessed, and correlations between changes in colonoscopic findings and changes in the two aforementioned fecal markers were examined. RESULTS: Among patients with mucosal healing (MH) and negative FIT or Fcal results at the initial colonoscopy, FIT and Fcal findings exhibited accuracies of 93% (38/41) and 79% (26/33), respectively, for predicting the results of the subsequent examination. Among the 24 patients who showed endoscopic activity at the precedent colonoscopy and MH at the subsequent examination, positive-to-negative conversion of FIT and Fcal findings at the subsequent examination was observed in 92% (12/13) and 62% (8/13) of patients, respectively. Among the 43 patients who showed endoscopic activity at both the precedent and subsequent examinations, Fcal findings reflected the change in endoscopic activity better than FIT results (r=0.59, p＜0.0001 vs r=0.30, p=0.054). CONCLUSIONS: The FIT is useful for confirming MH and the occurrence of relapse. In contrast, Fcal is useful for monitoring the mucosal status of patients with active inflammation.

Validity of Contrast-enhanced Ultrasonography and Dynamic Contrast-enhanced MR Enterography in the Assessment of Transmural Activity and Fibrosis in Crohn's Disease.

BACKGROUND AND AIMS: Increased small intestinal wall thickness correlates with both inflammatory activity and fibrosis in Crohn's disease [CD]. Assessment of perfusion holds promise as an objective marker distinguishing between the two conditions. Our primary aim was to determine if relative bowel wall perfusion measurements correlate with histopathological scores for inflammation or fibrosis in CD. METHODS: A total of 25 patients were investigated before elective surgery for small intestinal CD. Unenhanced ultrasonography [US] and magnetic resonance enterography [MRE] were applied to describe bowel wall thickness. Perfusion was assessed with contrast-enhanced US [CEUS] and dynamic contrast-enhanced MRE [DCE-MRE]. Histopathology was used as gold standard. RESULTS: Compared with histopathology, the mean wall thickness was 0.4 mm greater on US [range -0.3 to 1.0, p = 0.24] and 1.4 mm greater on MR [0.4 to 2.3, p = 0.006]. No correlation was found between the severity of inflammation or fibrosis on histopathology, and either DCE-MRE [r = -0.13, p = 0.54 for inflammation and r = 0.41, p = 0.05 for fibrosis] or CEUS [r = 0.16, p = 0.45 for inflammation and r = -0.28, p = 0.19 for fibrosis]. Wall thickness assessed with US was correlated with both histological inflammation [r = 0.611, p = 0.0012] and fibrosis [r = 0.399, p = 0.048]. The same was not true for MR [r = 0.41, p = 0.047 for inflammation and r = 0.29, p = 0.16 for fibrosis]. CONCLUSIONS: Bowel wall thickness assessed with US is a valid marker of inflammation in small intestinal CD. However, relative contrast enhancement of US or of MRE cannot distinguish between inflammatory activity and fibrosis.