AGA Clinical Practice Update on the Role of Intestinal Ultrasound in Inflammatory Bowel Disease: Commentary.

DESCRIPTION: In the past 3 years, the use of intestinal ultrasound (IUS) for monitoring inflammatory bowel disease in clinical practice has grown substantially in the United States. This American Gastroenterological Association (AGA) Institute Clinical Practice Update (CPU) aims to review the available evidence and guidance regarding the role of intestinal ultrasound in inflammatory bowel disease care. METHODS: This CPU was commissioned and approved by the AGA Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPUC and external peer review through standard procedures of Clinical Gastroenterology and Hepatology. This expert commentary incorporates important and recently published studies in this field, and it reflects the experiences of the multidisciplinary group of authors composed of adult and pediatric gastroenterologists.

Postoperative Ustekinumab Drug Levels and Disease Activity in Patients with Crohn's Disease.

AIMS: This study investigated how post-operative ustekinumab levels relate to surgery type, endoscopic, biochemical, and clinical outcomes in patients with Crohn's Disease. METHODS: A retrospective study of patients with Crohn's Disease with a disease-related operation between 2016 and 2022 assessed outcomes based on ustekinumab levels. Patients were included if they had an ustekinumab trough level within two years post-operatively. Patients were separated into groups based on whether their ustekinumab trough levels were adequate, defined as ≥ 4 µg/mL, or suboptimal < 4 µg/mL. A subset of patients with ustekinumab levels taken within two years both before and after surgery was compared to non-surgical treatment-escalated controls outside the initial patient set. Harvey-Bradshaw index was used to evaluate clinical disease activity. Rutgeert's and Simple Endoscopic Score for Crohn's Disease was used to evaluate endoscopic disease activity. C-reactive protein and fecal calprotectin values were collected to evaluate the molecular inflammatory disease state. CBC data were used to evaluate anemia. RESULTS: Forty-four patients were identified, which had ustekinumab levels after Crohn's Disease-related surgery. Twelve of these patients had pre-operative levels and were compared to 26 non-surgical treatment-escalated controls. No relationship between ustekinumab levels and endoscopic or clinical disease activity post-operatively was found. This also held true when looking at different surgery types. Adequate levels of ustekinumab post-operatively yielded lower risk of anemia. Surgery itself did not have an impact on ustekinumab levels. CONCLUSIONS: This study provided new insights into how post-operative ustekinumab levels impact several factors in patients having undergone Crohn's disease-related surgery.

The Role of Fecal Microbiota Transplantation in the Induction of Remission in Ulcerative Colitis.

BACKGROUND: Considerable research supports an important role for the microbiome and/or microbiome-host immune system interactions in the pathogenesis of inflammatory bowel disease (IBD). Consequently, microbiota-modulating interventions, such as fecal microbiota transplantation (FMT), have attracted interest in the management of IBD, including ulcerative colitis (UC). SUMMARY: While the clinical response to FMT in UC has varied between different studies, results to date may offer guidance toward optimal use of FMT. Thus, increased microbiome biodiversity, the presence of short-chain fatty acid-producing bacteria, Clostridium clusters IV and XIVa, Odoribacter splanchnicus, and reduced levels of Caudovirales bacteriophages have been identified as characteristics of the donor microbiome that predict a positive response. However, inconsistency in FMT protocol between studies confounds their interpretation, so it is currently difficult to predict response and premature to recommend FMT, in general, as a treatment for UC. Additional randomized controlled trials designed based on previous findings and employing a standardized protocol are needed to define the role of FMT in the management of UC. KEY MESSAGES: There is a well-developed rationale for the use of microbiome-modulating interventions in UC. Despite variations in study protocol and limitations in study design that confound their interpretation, FMT seems to benefit patients with UC, overall. Available data identify factors predicting FMT response and should lead to the development of optimal FMT study protocols.

Day Care Attendance and Infectious Complications in Children Born to Mothers With Inflammatory Bowel Disease.

Active inflammation during pregnancy in women with inflammatory bowel disease (IBD) is a risk factor for clinical relapse.1,2 In utero exposure to biologics is not associated with adverse pregnancy outcomes3 or infections in infants born to mothers with IBD.1,2,4 However, prior studies did not account for day care exposure in the first year of life, which is an established risk factor for infection in the general population. We aimed to determine whether children born to mothers with IBD have an increased rate of infection when attending day care in the first year after exposure to biologic therapy in utero.

P013 Resolution of Infliximab Associated Infusion Hypersensitivity After Switching to Biosimilar Infliximab-dyyb.

CASE: Background: Administration of infliximab for the treatment of inflammatory bowel disease has a well-recognized risk of infusion-related (IR) adverse events. The recent introduction of the biosimilar infliximab-dyyb (Inflectra®) has been shown to have similar efficacy with comparable safety profile when compared to infliximab; however, although the active ingredients are similar, the inactive ingredients are different. We present a case of a 26-year-old female with ulcerative colitis who had resolution of her IR hypersensitivity when switched from infliximab to infliximab-dyyb. CASE DESCRIPTION: A 26-year-old female with a past medical history of ulcerative pancolitis presented to our clinic with the chief complaint of rash associated with her infliximab infusions. She described pruritic raised lesions which would occur on her upper and lower extremities during her infusions. She denied any shortness of breath or wheezing, and her symptoms were well controlled with methylprednisolone 40mg IV prior to her infusions. Previously, she had been treated for her UC with oral mesalamine, azathioprine and intermittent prednisone and did not have any adverse reactions to these medications. She has no known allergies to other medications and her peripheral eosinophil count was 1.6%. She was initially started on infliximab 5mg/kg every 8 weeks since 2013 and had achieved clinical as well as endoscopic remission with her most recent colonoscopy graded as Mayo 0. On account of her infusion reaction, drug antibodies were checked but were not detected. Infliximab level was 8.8 µg/ml. Due to insurance she was required to switch to infliximab-dyyb. After switching to the biosimilar, she has not had any infusion related reactions and no longer requires premedication with methylprednisolone with her infusions. DISCUSSION: Immediate IR reactions have been reported in 5-23% of IBD patients receiving infliximab and those who develop antibodies towards infliximab have a 2-fold risk of acute IR events. Side effects have been reported to be the primary reason for discontinuation of infliximab, and studies have shown that discontinuation can lead to an increased risk of relapse of inflammatory bowel disease. Although infliximab and infliximab-dyyb have analogous active ingredients, the inactive ingredients differ. Specifically, infliximab-dyyb lacks monobasic sodium phosphate and dibasic sodium phosphate, which acts as an emulsifier which we believe contributed to her IR with originator biologic infliximab. It is important to recognize these differences as IR hypersensitivities may be attributed to inactive ingredients; especially when antibodies are negative. Our case report suggests that a switch to biosimilar infliximab in patients may provide added benefit especially in those that have reactions occurring from inactive ingredients in the originator biologic.

Positioning biologics and small molecules in the management of moderate to severe ulcerative colitis.

PURPOSE OF REVIEW: This review addresses the selection of biologic and small molecule therapy for patients with moderate to severe ulcerative colitis (UC). With several new treatment options approved within the past few years, an update in positioning is timely and relevant. RECENT FINDINGS: Updates on the safety and comparative efficacy of approved therapeutic agents for UC are presented. Newly approved therapies including tofacitinib and ustekinumab, as well as where to position these treatments are discussed. Data on the first-ever head-to-head trial of biologic therapy in UC are examined. This review provides an evidence-based overview of the optimal management strategies of patients in both the inpatient and outpatient settings. SUMMARY: As we move closer towards the goal of personalized therapy for our patients with UC, we hope to better select appropriate and effective treatment options. Newly approved therapies provide us with additional options for management. Future advancements in predictive serologic, mucosal, genetic, and fecal markers can enable us to tailor therapy to an individual patient.

The microbiome and inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic immune-mediated disease affecting the gastrointestinal tract. IBD consists of 2 subtypes: ulcerative colitis and Crohn disease. IBD is thought to develop as a result of interactions between environmental, microbial, and immune-mediated factors in a genetically susceptible host. Of late, the potential role of the microbiome in the development, progression, and treatment of IBD has been a subject of considerable interest and enquiry. Indeed, studies in human subjects have shown that the gut microbiome is different in patients with IBD compared with that in healthy control subjects. Other evidence in support of a fundamental role for the microbiome in patients with IBD includes identification of mutations in genes involved in microbiome-immune interactions among patients with IBD and epidemiologic observations implicating such microbiota-modulating risk factors as antibiotic use, cigarette smoking, levels of sanitation, and diet in the pathogenesis of IBD. Consequently, there has been much interest in the possible benefits of microbiome-modulating interventions, such as probiotics, prebiotics, antibiotics, fecal microbiota transplantation, and gene manipulation in the treatment of IBD. In this review we will discuss the role of the gut microbiome in patients with IBD; our focus will be on human studies.

Methotrexate Is Not Superior to Placebo in Maintaining Steroid-Free Response or Remission in Ulcerative Colitis.

BACKGROUND & AIMS: Parenteral methotrexate induces clinical remission but not endoscopic improvement of mucosal inflammation in patients with ulcerative colitis (UC). We performed a randomized, placebo-controlled trial to assess the efficacy of parenteral methotrexate in maintaining steroid-free response or remission in patients with UC after induction therapy with methotrexate and steroids. METHODS: We performed a 48-week trial, from February 2012 through May 2016, of 179 patients with active UC (Mayo score of 6-12 with endoscopy subscore ≥ 2) despite previous conventional or biological therapy. The study comprised a 16-week open label methotrexate induction period followed by a 32-week double-blind, placebo-controlled maintenance period. Patients were given subcutaneous methotrexate (25 mg/wk) and a 12-week steroid taper. At week 16, steroid-free responders were randomly assigned to groups that either continued methotrexate (25 mg/wk, n = 44) or were given placebo (n = 40) until week 48. We compared the efficacy of treatment by analyzing the proportion of patients who remained relapse free and were in remission at week 48 without use of steroids or other medications to control disease activity. RESULTS: Ninety-one patients (51%) achieved response at week 16, and 84 patients were included in the maintenance period study. During this period, 60% of patients in the placebo group (24/40) and 66% in the methotrexate group (29/44) had a relapse of UC (P = .75). At week 48, 30% of patients in the placebo group (12/40) and 27% of patients in the methotrexate group (12/44) were in steroid-free clinical remission without need for additional therapies (P = .86). No new safety signals for methotrexate were detected. CONCLUSIONS: Parenteral methotrexate (25 mg/wk) was not superior to placebo in preventing relapses of UC in patients who achieved steroid-free response during induction therapy. ClinicalTrials.gov, Number: NCT01393405.

Lack of placental transfer of certolizumab pegol during pregnancy: results from CRIB, a prospective, postmarketing, pharmacokinetic study.

OBJECTIVES: There is a need for effective and safe treatment during pregnancy in women with chronic inflammatory diseases. This study evaluated placental transfer of certolizumab pegol (CZP), an Fc-free anti-tumour necrosis factor drug, from CZP-treated pregnant women to their infants. METHODS: CRIB was a pharmacokinetic (PK) study of women ≥30 weeks pregnant receiving commercial CZP for a locally approved indication (last dose ≤35 days prior to delivery). Blood samples were collected from mothers, umbilical cords and infants at delivery, and infants again at weeks 4 and 8 post-delivery. CZP plasma concentrations were measured with a highly sensitive and CZP-specific electrochemiluminescence immunoassay (lower limit of quantification 0.032 µg/mL). RESULTS: Sixteen women entered and completed the study. Maternal CZP plasma levels at delivery were within the expected therapeutic range (median [range] 24.4 [5.0-49.4] µg/mL). Of the 16 infants, 2 were excluded from the per-protocol set: 1 due to missing data at birth and 1 due to implausible PK data. Of the remaining 14 infants, 13 had no quantifiable CZP levels at birth (<0.032 µg/mL), and 1 had a minimal CZP level of 0.042 µg/mL (infant/mother plasma ratio 0.0009); no infants had quantifiable CZP levels at weeks 4 and 8. Of 16 umbilical cord samples, 1 was excluded due to missing data; 3/15 had quantifiable CZP levels (maximum 0.048 µg/mL). CONCLUSIONS: There was no to minimal placental transfer of CZP from mothers to infants, suggesting lack of in utero foetal exposure during the third trimester. These results support continuation of CZP treatment during pregnancy, when considered necessary. TRIAL REGISTRATION NUMBER: NCT02019602; Results.

Polymorphisms of 5-HTT LPR and GNß3 825C>T and Response to Antidepressant Treatment in Functional Dyspepsia: A Study from The Functional Dyspepsia Treatment Trial.

OBJECTIVES: The Functional Dyspepsia Treatment Trial reported that amitriptyline (AMI) was associated with adequate relief of functional dyspepsia (FD) symptoms, but the pharmacogenetics of antidepressant response in FD are not known. GNß3 825C>T CC genotype has been previously linked to FD and TT genotype to antidepressant response in depression. The ss genotype of the 5-HTT LPR variant of the serotonin transporter gene (SLC6A4) has been linked to selective serotonin reuptake inhibitor (SSRI) response. We aimed to examine whether GNß3 825C>T and 5-HTT LPR polymorphisms result in differential treatment effects in FD patients receiving antidepressant therapy. METHODS: Participants were randomized to receive placebo, 50 mg AMI, or 10 mg escitalopram (ESC). The primary end point was adequate relief for ≥5 weeks of the last 10 weeks. Genotyping of GNß3 825C>T and 5-HTT LPR was performed utilizing PCR-based methods. RESULTS: GNß3 825C>T and 5-HTT LPR genotype data were available for 256 (88%) and 246 (84%) patients, respectively. Both polymorphisms were in Hardy-Weinberg equilibrium. In tests for differential treatment, neither 5-HTT LPR nor GNß3 825C>T genotype influenced response to therapy (P=0.89 and P=0.54, respectively). Although there was a tendency for a more favorable response to ESC in the SS/LS genotype compared to the LL genotype groups (40% vs. 31% reporting adequate relief of FD symptoms) among those in the ESC treatment arm, this was not significant (P=0.43). CONCLUSIONS: GNß3 825C>T and 5-HTT LPR genetic variants do not alter treatment response to tricyclic and SSRI antidepressants in FD.

Inflammatory Bowel Disease: Pathophysiology and Current Therapeutic Approaches.

Inflammatory bowel diseases, most commonly categorized as Crohn's disease and ulcerative colitis, are immune mediated chronic inflammatory disorders of the gastrointestinal tract. The etiopathogenesis is multifactorial with different environmental, genetic, immune mediated, and gut microbial factors playing important role. The current goals of therapy are to improve clinical symptoms, control inflammation, prevent complications, and improve quality of life. Different therapeutic agents, with their indications, mechanisms of action, and side effects are discussed in this chapter. Anti-integrin therapy, a newer therapeutic class, with its potential beneficial role in both Crohn's disease and ulcerative colitis is also mentioned. In the end, therapeutic algorithms for both diseases are reviewed.

Effect of Amitriptyline and Escitalopram on Functional Dyspepsia: A Multicenter, Randomized Controlled Study.

BACKGROUND & AIMS: Antidepressants are frequently prescribed to treat functional dyspepsia (FD), a common disorder characterized by upper abdominal symptoms, including discomfort or postprandial fullness. However, there is little evidence of the efficacy of these drugs in patients with FD. We performed a randomized, double-blind, placebo-controlled trial to evaluate the effects of antidepressant therapy on symptoms, gastric emptying (GE), and meal-induced satiety in patients with FD. METHODS: We performed a study at 8 North American sites of patients who met the Rome II criteria for FD and did not have depression or use antidepressants. Patients (n = 292; 44 ± 15 years old, 75% were female, 70% with dysmotility-like FD, and 30% with ulcer-like FD) were randomly assigned to groups given placebo, 50 mg amitriptyline, or 10 mg escitalopram for 10 weeks. The primary end point was adequate relief of FD symptoms for ≥5 weeks of the last 10 weeks (of 12). Secondary end points included GE time, maximum tolerated volume in Nutrient Drink Test, and FD-related quality of life. RESULTS: An adequate relief response was reported by 39 subjects given placebo (40%), 51 given amitriptyline (53%), and 37 given escitalopram (38%) (P = .05, after treatment, adjusted for baseline balancing factors including all subjects). Subjects with ulcer-like FD given amitriptyline were >3-fold more likely to report adequate relief than those given placebo (odds ratio = 3.1; 95% confidence interval: 1.1-9.0). Neither amitriptyline nor escitalopram appeared to affect GE or meal-induced satiety after the 10-week period in any group. Subjects with delayed GE were less likely to report adequate relief than subjects with normal GE (odds ratio = 0.4; 95% confidence interval: 0.2-0.8). Both antidepressants improved overall quality of life. CONCLUSIONS: Amitriptyline, but not escitalopram, appears to benefit some patients with FD, particularly those with ulcer-like (painful) FD. Patients with delayed GE do not respond to these drugs. ClinicalTrials.gov ID: NCT00248651.

Cancer surveillance in ulcerative colitis and Crohn's disease: new strategies.

PURPOSE OF REVIEW: Inflammatory bowel disease (IBD) patients have a higher incidence of colon cancer than the general population. Colon cancer surveillance has traditionally involved taking numerous random biopsies to provide sufficient yield to detect dysplasia. Recently, consensus guidelines have been published which promote the use of chromoendoscopy for IBD colon cancer surveillance. This presents a new set of opportunities and challenges in the evaluation and management of dysplasia in IBD. RECENT FINDINGS: Dysplasia, previously thought to be 'invisible' to the endoscopist, is now considered to be 'visible' in the majority of cases with the advent of the use of high-definition endoscopy and chromoendoscopy. This changes how we manage dysplastic lesions, providing the patient options for endoscopic resection rather than promoting total proctocolectomy. SUMMARY: Implemention of chromoendoscopy may require additional training for endoscopists unfamiliar with the technique. However, if this proves to be cost-effective and provides a higher sensitivity in dysplasia detection, then widespread education and implementation will be well worth the efforts. To do so, future studies will need to prove its benefits in preventing or reducing colon cancer morbidity and mortality in this high-risk patient population.

MicroRNA signatures differentiate Crohn's disease from ulcerative colitis.

BACKGROUND: Excessive and inappropriate immune responses are the hallmark of several autoimmune disorders, including the inflammatory bowel diseases (IBD): Crohn's disease (CD) and ulcerative colitis (UC). A complex etiology involving both environmental and genetic factors influences IBD pathogenesis. The role of microRNAs (miRNAs), noncoding RNAs involved in regulating numerous biological processes, to IBD pathology, in terms of initiation and progression, remains ill-defined. In the present study, we evaluated the relationship between colon, peripheral blood, and saliva whole miRNome expression in IBD patients and non-inflammatory bowel disease (non-IBD) controls to identify miRNAs that could discriminate CD from UC. Quantitative real-time PCR (qRT-PCR) was used to validate and assess miRNA expression. RESULTS: Microarray analysis demonstrated that upwards of twenty six miRNAs were changed in CD and UC colon biopsies relative to the non-IBD controls. CD was associated with the differential expression of 10 miRNAs while UC was associated with 6 miRNAs in matched colon tissues. CD was associated with altered expression of 6 miRNAs while UC was associated with 9 miRNAs in whole blood. Expression of miR-101 in CD patients and miR-21, miR-31, miR-142-3p, and miR-142-5p in UC patients were altered in saliva. CONCLUSIONS: Our results suggest that there is specific miRNA expression patterns associated with UC versus CD in three separate tissue/body fluids (colon, blood, and saliva). Further, the aberrant miRNA expression profiles indicate that miRNAs may be contributory to IBD pathogenesis, or at least reflect the underlying inflammation. Scrutinizing miRNA expression in saliva and blood samples may be beneficial in monitoring or diagnosing disease in IBD patients. A panel of miRNAs (miR-19a, miR-21, miR-31, miR-101, miR-146a, and miR-375) may be used as markers to identify and discriminate between CD and UC.

Medical and surgical complications of inflammatory bowel disease in the elderly: a systematic review.

BACKGROUND/AIMS: The complications of therapy, hospitalization, and surgery related to inflammatory bowel disease (IBD) in the elderly are not well described. While multiple reviews have described the management and complications of elderly patients with IBD, none have been performed in a systematic fashion. METHODS: We performed a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to evaluate the association between elderly patients with IBD and complications from therapy, hospitalizations, and surgery. Eligible studies were identified via structured keyword searches in PubMed and manual literature searches. RESULTS: A total of 5,644 publications were identified. Of these, fourteen studies met inclusion criteria, encompassing 963 elderly IBD patients (113 Crohn's disease and 850 ulcerative colitis patients), over 37,000 hospitalizations of elderly IBD patients and over 4,500 controls. Consistent associations were observed between increased age and higher nocturnal stool frequency post-ileal pouch anal anastomosis. Only two studies met inclusion criteria for medication-related complications, one observed an increased mortality and infection risk among elderly patients treated with tumor necrosis factor antagonists and the other observed increased hospital-related complications among elderly patients treated with steroids. CONCLUSIONS: Elderly patients with IBD are at an increased risk of hospital- and therapy-related complications. We found a paucity of high-quality studies evaluating outcomes in elderly patients with IBD. Further studies of elderly patients with IBD are needed to further evaluate the effect of age on medical and surgical complications.

Vitamin D deficiency and corticosteroid use are risk factors for low bone mineral density in inflammatory bowel disease patients.

BACKGROUND: As several factors can contribute to low bone mineral density (BMD), we investigated the role of vitamin D in low BMD while controlling for other risk factors in inflammatory bowel diseases (IBD) patients. METHODS: We conducted a prospective cross-sectional study between 2008 and 2012 in adult IBD patients. Demographic data including age, gender, ethnicity, BMI, along with disease type and location, vitamin D levels, prior corticosteroid use, and anti-TNF use were recorded and evaluated with DEXA results. RESULTS: A total of 166 patients [105 Crohn's disease (CD), 61 ulcerative colitis (UC)] qualified for the study. Low BMD was found in 40%, twice as frequently in CD than in UC (p = 0.048). Higher prevalence of low BMD was associated with those of male gender (p = 0.05), Asian ethnicity (p = 0.02), and history of corticosteroid use (p = 0.001). Age, body mass index, or disease location did not increase the risk of low BMD. The overall prevalence of low vitamin D was 60%, with insufficiency (25-hydroxy levels between 20 and 30 ng/mL) found in 37% and deficiency (levels <20 ng/mL) found in 23% of the patients. Vitamin D insufficient and deficient patients were two times (p = 0.049) and almost 3 times (p = 0.02) as likely to have low BMD, respectively. CONCLUSIONS: Low vitamin D, male gender, Asian ethnicity, CD, and corticosteroid use significantly increased the risk of having low BMD, while age and disease location did not affect BMD in our IBD population. It remains important to evaluate for vitamin D nutritional deficiency and limit corticosteroid use to help prevent low BMD in IBD patients.

Choosing Therapy for Moderate to Severe Crohn's Disease.

The availability of approved therapies for Crohn's disease has significantly increased over the past decade. To choose the appropriate therapy for the patient, ideally head to head studies, and data on positioning could help the provider individualize the decision. Due to the paucity of head-to-head trial data, we turn to network meta-analysis and real-world studies to help guide our treatment choices. Ultimately, the best approach is to consider each patient on an individual basis, taking into consideration the characteristics of their disease, individual risk factors, extra-intestinal manifestations, co-morbid conditions, patient age, cost, and personal preferences. In this review, we summarize the evidence comparing biologic as well as small molecule therapies for the treatment of moderate-to-severe Crohn's disease. We have summarized the evidence in relation to factors such as efficacy, fistulizing disease, pregnancy, infection risk, and co-existing conditions.

Therapeutic drug monitoring in patients with inflammatory bowel disease on ustekinumab.

OBJECTIVE: Therapeutic drug monitoring is used clinically to guide anti-tumor necrosis factor (TNF) therapy for inflammatory bowel disease (IBD), but its use for ustekinumab (UST) remains unclear. This study aimed to determine predictive variables of UST levels. METHODS: In this retrospective cohort of patients with IBD, UST trough levels were drawn at maintenance dosing. Relationships between UST trough levels and demographics, therapy, and outcomes were analyzed. Machine-learning models were used to infer combinatorial traits predictive of UST levels. RESULTS: Altogether 177 patients with IBD on UST had a mean UST trough level of 4.742 µg/mL. The injection schedule correlated significantly (P < 0.001) with UST levels. Naiveté to anti-TNFs correlated with higher UST levels (P = 0.048). Univariate analysis revealed that higher inflammatory biomarkers significantly correlated to lower UST levels and a lower Simple Endoscopic Score to Crohn's Disease to adequate UST levels (P = 0.018). Multivariate analysis identified body mass index (BMI), previous anti-TNF failure, and laboratory flare as predictors of UST levels with an area under the receiver operating characteristic curve (AUROC) of 0.72. The UST cut-off level of 5.77 µg/mL yielded a 0.79 AUROC, 80% sensitivity, and 81% specificity for predicting endoscopic remission of Crohn's disease. For the clinical remission end-point in ulcerative colitis, UST level of 4.73 µg/mL yielded a 0.69 AUROC, 53% sensitivity, and 86% specificity. CONCLUSIONS: Higher UST levels correlated with less disease activity. BMI was an important consideration for UST response as well. Therefore, UST dose adjustments to reach target levels may optimize response.