Toward a personalized medicine approach to the management of inflammatory bowel disease

Oral administration of RDP58 ameliorated DSS-induced colitis in intestinal microbiota dependent manner

BACKGROUND

Although the pathogenesis of inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), has not been fully elucidated, accumulating researches suggest that intestinal microbiota imbalance contributes to the development of IBD in patients and animal models. RDP58, a peptide-based computer-assisted rational design, has been demonstrated to be effective in protecting against a wide range of autoimmune and inflammatory diseases. However, the underlying mechanism by which RDP58 protects against IBD mediated by intestinal microbiota has yet to be elucidated.

METHODS

The colitis model was induced by continuously administering 2.5 % (wt/vol) dextran sodium sulfate (DSS) solution for 7 days. The manifestations of colon inflammation were assessed via daily weight changes, colon length, tumor necrosis factor-alpha (TNF-α) level, disease activity index (DAI) score, pathology score, and intestinal barrier permeability. Intestinal microbiota analysis was carried out by 16S-rRNA sequencing. Colonic short chain fatty acids (SCFAs) and regulatory T cells (Tregs) were also detected. To further confirm the protective effect of RDP58 on intestinal microbiota, broad-spectrum antibiotic cocktail (ABX) treatment and fecal microbial transplantation (FMT) experiment were performed.

RESULTS

Oral administration of RDP58 ameliorated DSS-induced mice colitis by altering the diversity and composition of intestinal microbiota. Notably, RDP58 significantly upregulated SCFAs-producing microbiota, thereby promoting the generation of Tregs. ABX and FMT were performed to verify the above mechanism.

CONCLUSIONS

RDP58 ameliorated DSS-induced colitis through altering intestinal microbiota and enhancing SCFAs and Tregs production in intestinal microbiota dependent manner, potentially provide a novel therapy for IBD.

Current status of novel biologics and small molecule drugs in the individualized treatment of inflammatory bowel disease

Treatment strategies for inflammatory bowel disease (IBD) are rapidly evolving with the development of biologics and small molecule drugs (SMDs). However, these drugs are not guaranteed to be effective in all patients, and a “ceiling effect” of biologic monotherapy may occur. This issue highlights an unmet need for optimizing the use of biologics and predicting therapeutic responses. Thus, the development of new drugs with novel mechanisms of action is urgently needed for patients with primary nonresponse and secondary loss of response to conventional biologics and SMDs. In addition, combining different biologics or SMDs has been proposed as a novel strategy to enhance treatment efficacy in IBD, which theoretically has multidimensional anti-inflammatory potential. Based on the current evidence available for IBD, dual targeted therapy may be a promising strategy for refractory IBD patients who have failed in multiple biologic trea-tments or who have extraintestinal manifestation. Additionally, identifying the subgroup of IBD patients who are responding to biological combination therapies is also equally important in stable disease remission. In this review, we sum-marize the newly developed biologics and SMDs and the current status of bio-logics/SMDs to highlight the development of individualized treatment in IBD.

Orally Administered Platinum Nanomarkers for Urinary Monitoring of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic relapsing autoimmune disease with rising incidence worldwide. There is an increasing desire for non-invasive diagnostic tools to enable simple and sensitive IBD monitoring. Here, we report an orally administered nanosensor which will dissociate into ultrasmall platinum nanoclusters (PtNCs) in IBD-related inflammatory microenvironments. By exploiting the enzyme-mimicking activity of PtNCs and the precise bandpass filterability of kidney, the released-PtNCs can be detected in a scalable urinary readout, such as fluorescence and volumetric bar-chart chip (V-Chip), for point-of-care (POC) analysis. Our results demonstrate that the nanosensors exhibit significant signal differences between IBD-model mice and healthy mice, which is more sensitive than clinical ELISA assay based on fecal calprotectin. Such a non-invasive diagnostic modality significantly assists in the personalized assessment of pharmacological and follow-up efficacy. We envision that this modular conception will promote the rapid diagnosis of diverse diseases by changing specific responsive components.

The Development and Initial Findings of A Study of a Prospective Adult Research Cohort with Inflammatory Bowel Disease (SPARC IBD)

BACKGROUND

Clinical and molecular subcategories of inflammatory bowel disease (IBD) are needed to discover mechanisms of disease and predictors of response and disease relapse. We aimed to develop a study of a prospective adult research cohort with IBD (SPARC IBD) including longitudinal clinical and patient-reported data and biosamples.

METHODS

We established a cohort of adults with IBD from a geographically diverse sample of patients across the United States with standardized data and biosample collection methods and sample processing techniques. At enrollment and at time of lower endoscopy, patient-reported outcomes (PRO), clinical data, and endoscopy scoring indices are captured. Patient-reported outcomes are collected quarterly. The quality of clinical data entry after the first year of the study was assessed.

RESULTS

Through January 2020, 3029 patients were enrolled in SPARC, of whom 66.1% have Crohn's disease (CD), 32.2% have ulcerative colitis (UC), and 1.7% have IBD-unclassified. Among patients enrolled, 990 underwent colonoscopy. Remission rates were 63.9% in the CD group and 80.6% in the UC group. In the quality study of the cohort, there was 96% agreement on year of diagnosis and 97% agreement on IBD subtype. There was 91% overall agreement describing UC extent as left-sided vs extensive or pancolitis. The overall agreement for CD behavior was 83%.

CONCLUSION

The SPARC IBD is an ongoing large prospective cohort with longitudinal standardized collection of clinical data, biosamples, and PROs representing a unique resource aimed to drive discovery of clinical and molecular markers that will meet the needs of precision medicine in IBD.

Therapeutic drug monitoring in inflammatory bowel disease reduces unnecessary use of infliximab with substantial associated cost-savings

BACKGROUND

Therapeutic drug monitoring (TDM) of infliximab (IFX) levels in inflammatory bowel disease (IBD) patients can help to guide dose adjustments or changes to therapy for selected patients in remission or with secondary loss of response (LOR).

AIMS

To determine how IFX TDM is utilised in a real-life clinical setting and to quantify the potential for TDM to reduce the unnecessary use of IFX.

METHODS

Data from all public IBD IFX level testing performed across Australia were prospectively collected from June 2016 to July 2017 to assess physician-reported for testing indications (induction, in remission or LOR) and associated results. The hypothetical influence of IFX TDM was based on an optimal therapeutic range of 6-10 mg/L for mucosal healing.

RESULTS

Secondary LOR (reactive TDM) was the most common indication for TDM. These patients have consistently lower median IFX levels: 3.02 mg/L (IQR 1.14-6.67 mg/L) versus 5.22 mg/L (IQR 2.70-8.12 mg/L), P = 0.0001 compared with patients in remission (proactive TDM). TDM helped to identify unnecessary use of IFX in 30.6% of the TDM tests performed in luminal Crohn disease and ulcerative colitis patients, with an associated drug cost saving of $531.38 per IFX TDM test episode. Unnecessary IFX use was identified in 38.9% (96/247) of reactive IFX TDM tests performed and in 19.3% (35/181) of proactive testing.

CONCLUSION

Use of both reactive and proactive IFX TDM is cost-effective for IBD management as it informs the clinician where unnecessary use of IFX can be stopped.

Clinical and Genetic Factors Associated With Complications After Crohn's Ileocolectomy

BACKGROUND

Ileocolectomy is the most common surgery performed for Crohn's disease, and postoperative complications occur frequently. There has been minimal evaluation of complications after ileocolectomy as a function of both clinical and genetic factors.

OBJECTIVE

The purpose of this study was to evaluate both genetic and clinical factors associated with complications after Crohn's ileocolectomy.

DESIGN

This was a retrospective clinical and genetic cohort study.

SETTINGS

This study was conducted at a high-volume tertiary care center.

PATIENTS

We identified 269 patients with Crohn's disease who had undergone 287 ileocolectomies at our institution between July 2008 and October 2018.

MAIN OUTCOME MEASURES

We measured the association of complications with a combination of clinical factors and 6 Crohn's-associated single nucleotide polymorphisms in NOD2 (rs2076756, rs2066844, and rs2066845), IRGM (rs4958847 and rs13361189), and ATG16L1 (rs2241880).

RESULTS

There were 86 ileocolectomies of 287 (30%) with complications requiring intervention. The single nucleotide polymorphism rs13361189 in the gene IRGM was significantly associated with complications on univariate and multivariate analysis. There were 61 patients with a variant at the rs13361189 single nucleotide polymorphism and 26 of them had complications, although only 55 of the 208 wild-type patients had complications (43% vs 26%; OR = 2.1; p = 0.02). Other significant factors associated with complication after ileocolectomy were open surgery, placement of a proximal ileostomy, and a greater perioperative decrease in hematocrit.

LIMITATIONS

This study was limited by its retrospective design and inherent selection bias.

CONCLUSIONS

In addition to clinical risk factors, the rs13361189 single nucleotide polymorphism in the IRGM gene was independently associated with complications after ileocolectomy for Crohn's disease. The use of such genetic determinants may identify patients at increased risk for surgical complications after ileocolectomy. See Video Abstract at http://links.lww.com/DCR/B124. FACTORES CLÍNICOS Y GENÉTICOS ASOCIADOS CON COMPLICACIONES DESPUÉS DE LA ILEOCOLECTOMÍA DE CROHN: La ileocolectomía es la cirugía más común realizada para la enfermedad de Crohn y con frecuencia ocurren complicaciones postoperatorias. Ha habido una evaluación mínima de complicaciones después de la ileocolectomía, en función de factores clínicos y genéticos.Evaluar factores genéticos y clínicos asociados con complicaciones, después de la ileocolectomía por Crohn.Estudio retrospectivo de cohorte clínico y genético.Este estudio se realizó en un centro de atención terciaria de alto volumen.Identificamos a 269 pacientes con enfermedad de Crohn, sometidos a 287 ileocolectomías en nuestra institución, entre julio de 2008 y octubre de 2018.La asociación de complicaciones con una combinación de factores clínicos y seis polimorfismos de un solo nucleótido asociados a Crohn en NOD2 (rs2076756, rs2066844 y rs2066845), IRGM (rs4958847 y rs13361189) y ATG16L1 (rs2241880).Hubieron 86 ileocolectomías en 287 (30%) pacientes con complicaciones que requirieron intervención. El polimorfismo de un solo nucleótido rs13361189 en el gen IRGM se asoció significativamente con complicaciones en el análisis univariado y multivariado. Hubieron 61 pacientes con una variante en el polimorfismo de un solo nucleótido rs13361189 y 26 de ellos tuvieron complicaciones, mientras que solo 55 de los 208 pacientes de tipo salvaje (WT) tuvieron complicaciones (43% vs 26%, OR 2.1, p = 0.02). Otros factores significativos asociados con las complicaciones después de la ileocolectomía fueron, la cirugía abierta, la colocación de una ileostomía proximal y una mayor disminución perioperatoria del hematocrito.Este estudio estuvo limitado por su diseño retrospectivo y sesgo de selección inherente.Además de los factores de riesgo clínicos, el polimorfismo de un solo nucleótido rs13361189 en el gen IRGM se asoció independientemente con complicaciones después de la ileocolectomía, para la enfermedad de Crohn. El uso de tales determinantes genéticos puede identificar a los pacientes con mayor riesgo de complicaciones quirúrgicas, después de la ileocolectomía. Consulte Video Resumen en http://links.lww.com/DCR/B124.

Biomarkers Predictive of Response to Thiopurine Therapy in Inflammatory Bowel Disease

The complex nature of inflammatory bowel disease (IBD) often results in treatment failure for many patients. With some patients cycling through multiple therapies before achieving a sustained period of remission, the ability to predict a patient's response to therapeutics could decrease the time from active disease to clinical remission and mucosal healing. The prospect of such individualized treatment of IBD would be aided by accurate biomarkers, both fecal and serological, which have to date shown value as indicators of IBD activity. Here we review the utility of generic biomarkers for inflammation or mucosal healing, such as calprotectin, C-reactive protein (CRP), and fecal hemoglobin (fHb) as predictors of response to treatment of IBD. We further provide a deeper insight into the utility of monitoring the thiopurine treatment by thiopurine metabolites or alternative hematologic parameters. In light of multiple recent publications of biomarkers and biological therapy, our focus in this review is predicting response to thiopurine treatment only, that is, Azathioprine and 6-Mercaptopurine.

Introducing Patterns of Variability for Overcoming Compensatory Adaptation of the Immune System to Immunomodulatory Agents: A Novel Method for Improving Clinical Response to Anti-TNF Therapies

Primary lack of response and secondary loss of response (LOR) are major obstacles to the use of anti–tumor necrosis factor (TNF)-based therapies in patients with rheumatoid arthritis or inflammatory bowel disease. Here, we review the mechanisms and methods for predicting LOR and the currently used methods for overcoming the ineffectiveness of anti-TNFs. The complex functions of TNF and anti-TNF antibodies, which can promote both pro- or anti-inflammatory actions, and the factors that affect the induction of immune tolerance to their effects are presented. The lack of rules and the continuous dynamics of the immune processes partly underlie the unpredictability of the response to anti-TNFs. Variability is inherent to biological systems, including immune processes, and intra/inter-patient variability has been described in the response to drugs. This variability is viewed as a compensatory adaptation mechanism of the immune system in response to drugs and may contribute to treatment LOR. Dose reductions and drug holidays have been tested in patients treated with anti-TNFs. Regular dose-based regimens may be incompatible with physiological variability, further contributing to treatment inefficacy. We present the concept of overcoming immune system adaptation to anti-TNFs by introducing patient-tailored patterns of variability to treatment regimens.

Genetic predictors of long-term response and trough levels of infliximab in crohn's disease

INTRODUCTION

Several factors, such as trough serum anti-TNF levels, have been associated with response to therapy in Crohn's disease. However, this association is observed after initiation of treatment. Identifying DNA variants may prove useful for predicting long-term response or failure to these drugs before initiation of treatment.

OBJECTIVE

To identify genetic variants associated with long-term response to infliximab and trough levels in Crohn's disease.

PATIENTS AND METHODS

An observational, longitudinal study was conducted. We analyzed blood samples from 132 infliximab-treated patients diagnosed with Crohn's disease from 2 hospitals. We genotyped 21 polymorphisms previously related to anti-TNF response in genes involved in the NFkB-mediated inflammatory response, TNFα-signaling and cytokines regulated by NFkB, using real-time PCR. Trough infliximab levels were measured using ELISA. The association between SNPs and time-to-failure (defined as the time from the initiation of induction therapy to the date of treatment withdrawal due to a primary or secondary failure) was analyzed using log-rank test. The association between SNPs and supra-(>7 μg/mL) or infratherapeutic (<3 μg/mL) infliximab trough levels was analyzed using a linear-by-linear association chi-squared test.

RESULTS

Two SNPs in TLR2, rs1816702 and rs3804099, and 1 SNP in TNFRSF1B, rs1061624, were associated with long-term response (up to ten years follow-up) to infliximab (HR, 0.13 [95%CI, 0.02-1.00], p < 0.05; HR, 0.39 [95%CI, 0.18-0.88], p < 0.05; and HR, 0.04 [95%CI, 0.18-0.92] p > 0.05, respectively). In addition, IL6 rs10499563 C and IL10 rs1800872 A were associated with supratherapeutic trough infliximab levels; IL10 rs3024505 T was associated with infratherapeutic levels (p < 0.05).

CONCLUSION

Genotyping of the variants identified in the genes encoding TLR2, TNFRSF1B, IL6 and IL10 reported herein represent a promising tool for the identification and selection of those patients who will benefit most from infliximab.

Accuracy of the new rapid test for monitoring adalimumab levels

BACKGROUND

The loss of response to adalimumab (ADL) has been related to low serum concentrations at trough. Currently, most methods commercially available for the quantification of ADL are enzyme-linked immunosorbent assay (ELISA) based, with a turnaround time of approximately 8 h, delaying the target dosage adjustment to the subsequent infusion. In this study, we aimed to evaluate the performance of the newly available rapid-test ADL quantification assay by comparing it with three established ELISA methods, using spiked samples and a set of clinical samples.

METHODS

Spiked samples from control donors and 120 serum samples from inflammatory bowel disease (IBD) patients undergoing ADL therapy were quantified using lateral flow Quantum Blue^® Adalimumab and, the ELISA formats from Immundiagnostik, R-Biopharm and an in-house assay.

RESULTS

The rapid-test assay had intraclass correlation coefficients of 0.590, 0.864 and 0.761 when comparing with the Immundiagnostik, R-Biopharm and in-house assays, respectively. For the five therapeutic windows, the accuracy was high: ADL rapid test compared with the Immundiagnostik (58-88%); R-Biopharm, 68-89%; and in house, 60-88%; and kappa statistics revealed 0.492-0.602, 0.531-0.659 and 0.545-0.682, respectively.

CONCLUSIONS

The Quantum Blue^® Adalimumab assay can replace the commonly used ELISA-based ADL quantification kits and it is a reliable alternative to these methods. This rapid-test assay enables the quantitative determination of ADL serum trough level in only 15 min. The developed assay allows measurement of ADL over a wide range. Hence, it represents a valuable tool for the clinician to assess the ADL trough level.

Vedolizumab exposure levels and clinical outcomes in ulcerative colitis: determining the potential for dose optimisation

BACKGROUND

Prospectively designed studies assessing the exposure-response profile of vedolizumab are lacking. Observational exposure-response data for vedolizumab are limited and have not been adjusted for potential confounding factors, particularly those that may affect vedolizumab clearance.

AIMS

To (a) investigate the vedolizumab exposure-response relationship after adjusting for potential confounding variables; (b) propose potential target serum vedolizumab concentrations for future study; (c) ascertain whether early vedolizumab serum concentrations were associated with short- and long-term clinical outcomes in adults with ulcerative colitis in GEMINI 1.

METHODS

Propensity-score-based case-matching analysis was performed using data from GEMINI 1 and an earlier large population pharmacokinetic study, with vedolizumab clearance or concentration as predictors of clinical remission and response, adjusted for age, weight, anti-tumour necrosis factor alpha therapy history, serum albumin and faecal calprotectin concentrations. Potential vedolizumab concentration targets at weeks 6, 14 and steady state were proposed. Association between early vedolizumab concentrations at weeks 2, 4 and 6 and clinical remission at weeks 14 and 52 was evaluated.

RESULTS

Among 693 patients with pharmacokinetic data at week 6, potential target vedolizumab concentrations at weeks 6, 14 and steady state were 37.1, 18.4 and 12.7 µg/mL respectively. Week 6 was identified as the earliest time at which vedolizumab concentrations were consistently associated with clinical remission at weeks 14 and 52.

CONCLUSIONS

In this comprehensively adjusted analysis, vedolizumab concentrations at week 6 were associated with short- and long-term remission. Potential induction and maintenance target concentrations were proposed for further study.

Use of Precision Medicine in Clinical Trials in Inflammatory Bowel Disease

The conventional drug development paradigm consists of a rigorous step-wise process that takes place over many years. Although this approach results in access to safe and effective new products, it is both costly and inefficient. Therefore, interest has emerged in clinical pharmacology, specifically an understanding of the inter- and intra-individual variability in pharmacokinetics and pharmacodynamics, to increase the efficiency of drug development in inflammatory bowel disease. A firm understanding of clinical pharmacology would benefit both drug development and clinical practice by allowing stratification of patients at baseline who would respond favorably to drugs with a certain mechanism of action and by identifying patients who may benefit from an accelerated dosing regimen or combination therapy. These principles are reviewed below.

Engineering Precision Medicine

Advances in genomic sequencing and bioinformatics have led to the prospect of precision medicine where therapeutics can be advised by the genetic background of individuals. For example, mapping cancer genomics has revealed numerous genes that affect the therapeutic outcome of a drug. Through materials and cell engineering, many opportunities exist for engineers to contribute to precision medicine, such as engineering biosensors for diagnosis and health status monitoring, developing smart formulations for the controlled release of drugs, programming immune cells for targeted cancer therapy, differentiating pluripotent stem cells into desired lineages, fabricating bioscaffolds that support cell growth, or constructing "organs-on-chips" that can screen the effects of drugs. Collective engineering efforts will help transform precision medicine into a more personalized and effective healthcare approach. As continuous progress is made in engineering techniques, more tools will be available to fully realize precision medicine's potential.

Advanced endoscopic imaging for diagnosis of inflammatory bowel diseases: Present and future perspectives

Crohn's disease and ulcerative colitis are chronic inflammatory bowel diseases (IBD) causing severe damage of the luminal gastrointestinal tract. Differential diagnosis between both disease entities is sometimes awkward requiring a multifactorial pathway, including clinical and laboratory data, radiological findings, histopathology and endoscopy. Apart from disease diagnosis, endoscopy in IBD plays a major role in prediction of disease severity and extent (i.e. mucosal healing) for tailored patient management and for screening of colitis-associated cancer and its precursor lesions. In this state-of-the-art review, we focus on current applications of endoscopy for diagnosis and surveillance of IBD. Moreover, we will discuss the latest guidelines on surveillance and provide an overview of the most recent developments in the field of endoscopic imaging and IBD.

Interactions Between Thiopurine Metabolites, Adalimumab, and Antibodies Against Adalimumab in Previously Infliximab-Treated Patients with Inflammatory Bowel Disease

BACKGROUND

Interactions between thiopurines and infliximab presumably contribute to superior effect of infliximab-thiopurine combination therapy in patients with inflammatory bowel disease (IBD). We examined whether principal cytotoxic thiopurine metabolites influence adalimumab (ADL) and anti-ADL antibodies (Abs).

METHODS

Ninety-eight IBD patients previously treated with infliximab (96%) in whom trough ADL and anti-ADL Abs had been assessed as part of their clinical care were included. Thiopurine metabolites [6-thioguanine nucleotides (6-TGN) and methylated mercaptopurine metabolites (6-MeMP)] were determined at similar time points.

RESULTS

ADL-thiopurine combination therapy was not associated with reduced anti-ADL Ab positivity compared to ADL monotherapy: 8/31 (26%) versus 19/67 (28%), p = 1.00. Concentrations of thiopurine metabolites were similar in anti-ADL Ab-positive and negative patients (6-TGN median 109 pmol/8 × 10⁸ RBC vs. 112, p = 0.80; 6-MeMP 448 RBC vs. 720, p = 0.94). ADL trough levels did not differ between anti-ADL Ab-negative patients on ADL-thiopurine combination therapy and those on monotherapy (9.5 μg/mL vs. 7.6, p = 0.31). ADL levels were also comparable between patients on ADL mono- and combination therapy after stratification for 6-TGN/6-MeMP quartiles. There were no correlations between levels of 6-TGN and ADL (r_P = - 0.17, p = 0.45; r_S = - 0.38, p = 0.08), or 6-MeMP and ADL (r_P = - 0.23, p = 0.31; r_S = - 0.35, p = 0.11). Anti-ADL Ab positivity was associated with ADL treatment failure (OR 6 [2-20], p < 0.01). Higher trough ADL (9.6 μg/mL vs. 7.3, p < 0.05), but not concomitant thiopurine treatment, metabolite levels, or dosage, was associated with clinical remission.

CONCLUSION

Effectiveness of ADL therapy associated with circulating ADL levels and anti-ADL Ab formation. In this study, there appeared no direct interactions between thiopurine metabolites and ADL or anti-ADL Abs.

A Systematic Review and Meta-Analysis of 6-Thioguanine Nucleotide Levels and Clinical Remission in Inflammatory Bowel Disease

BACKGROUND AND AIMS

Thiopurines are widely used in the management of inflammatory bowel diseases. However, their minimum effective dose and dose-response relationship remain undefined, and evidence about their use in clinical practice is mostly heterogeneous. This systematic review and meta-analysis aimed: i] to assess the clinical value of 6-thioguanine nucleotide thresholds; and ii] to compare mean 6-thioguanine nucleotide concentrations between patients in clinical remission vs. those with active disease.

METHODS

A systematic literature search was carried out using four databases. Statistical heterogeneity was assessed with the I2 statistic followed by subgroup and sensitivity analyses. Odds ratios were computed using the random-effects model.

RESULTS

A total of 1384 records were identified in the systematic search, of which 25 were retained for further analysis: 22 were used in the cut-off comparisons and 12 were used in the 6-thioguanine nucleotide mean differences analysis. The global odds ratio for remission in patients with 6-thioguanine nucleotide levels above the predefined thresholds was 3.95 (95% confidence interval [CI], 2.63-5.94; p < 0.001]. When considering the different thresholds individually, the odd ratios were significant for values above 235 pmol/8 × 108 and 250 pmol/8 × 108 red blood cells [2.25 and 4.71, respectively]. Mean 6-thioguanine nucleotide levels were higher among patients in clinical remission, with a pooled difference of 63.37 pmol/8 × 108 red blood cells [95% CI, 31.81-94.93; p < 0.001].

CONCLUSIONS

This study reinforces the link between 6-thioguanine nucleotide levels and clinical remission in inflammatory bowel diseases, also exploring the validity of specific 6-thioguanine nucleotide thresholds to predict clinical outcomes.

Medical versus surgical management of penetrating Crohn's disease: the current situation and future perspectives

The development of penetrating Crohn's disease (CD) occurs in up to 50% of patients over the course of their lifetime. While the presentation of these complications, including free perforation, intra-abdominal abscess, and enteric fistula, are usually obvious, the management can require a nuanced approach, with distinct short and long-term approaches. Areas covered: This review discusses medical and surgical methods of treating these complications, including the role of percutaneous drainage of abscesses, the implications of a stricture associated with a fistula, and the efficacy of postoperative anti-TNF therapy in preventing recurrence after surgical treatment. Expert commentary: An approach to the management of these complications that begins with control of sepsis, including broad-spectrum antibiotics, bowel rest, and nutritional support is proposed. The next appropriate step is a diagnostic evaluation to determine the utility of medical versus surgical therapy, considering the presence of a stricture and prior immunosuppressive therapy. Postoperative anti-TNF therapy, a highly effective method to prevent recurrence, should be considered in many cases.

Strategies for overcoming anti-tumor necrosis factor drug antibodies in inflammatory bowel disease: Case series and review of literature

Anti-tumor necrosis factor (TNF) biologics are currently amongst the most widely used and efficacious therapies for inflammatory bowel disease (IBD). The development of therapeutic drug monitoring for infliximab and adalimumab has allowed for measurement of drug levels and antidrug antibodies. This information can allow for manipulation of drug therapy and prediction of response. It has been shown that therapeutic anti-TNF drug levels are associated with maintenance of remission, and development of antidrug antibodies is predictive of loss of response. Studies suggest that a low level of drug antibodies, however, can at times be overcome by dose escalation of anti-TNF therapy or addition of an immunomodulator. We describe a retrospective case series of twelve IBD patients treated at the University of California-Irvine, who were on infliximab or adalimumab therapy and were found to have detectable but low-level antidrug antibodies. These patients underwent dose escalation of the drug or addition of an immunomodulator, with subsequent follow-up drug levels obtained. Eight of the twelve patients (75%) demonstrated resolution of antidrug antibodies, and were noted to have improvement in disease activity. Though data regarding overcoming low-level anti-TNF drug antibodies remains somewhat limited, cases described in the literature as well as our own experience suggest that this may be a viable strategy for preserving the use of an anti-TNF drug. Low-level anti-TNF drug antibodies may be overcome by dose escalation and/or addition of an immunomodulator, and can allow for clinical improvement in disease status. Therapeutic drug monitoring is an important tool to guide this strategy.

Crohn's disease

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract, with increasing incidence worldwide. Crohn's disease might result from a complex interplay between genetic susceptibility, environmental factors, and altered gut microbiota, leading to dysregulated innate and adaptive immune responses. The typical clinical scenario is a young patient presenting with abdominal pain, chronic diarrhoea, weight loss, and fatigue. Assessment of disease extent and of prognostic factors for complications is paramount to guide therapeutic decisions. Current strategies aim for deep and long-lasting remission, with the goal of preventing complications, such as surgery, and blocking disease progression. Central to these strategies is the introduction of early immunosuppression or combination therapy with biologicals in high-risk patients, combined with a tight and frequent control of inflammation, and adjustment of therapy on the basis of that assessment (treat to target strategy). The therapeutic armamentarium for Crohn's disease is expanding, and therefore the need to develop biomarkers that can predict response to therapies will become increasingly important for personalised medicine decisions in the near future. In this Seminar, we provide a physician-oriented overview of Crohn's disease in adults, ranging from epidemiology and cause to clinical diagnosis, natural history, patient stratification and clinical management, and ending with an overview of emerging therapies and future directions for research.

Novel Targeted Therapies for Inflammatory Bowel Disease

Our growing understanding of the immunopathogenesis of inflammatory bowel disease (IBD) has opened new avenues for developing targeted therapies. These advances in treatment options targeting different mechanisms of action offer new hope for personalized management. In this review we highlight emerging novel and easily administered therapeutics that may be viable candidates for the management of IBD, such as antibodies against interleukin 6 (IL-6) and IL-12/23, small molecules including Janus kinase inhibitors, antisense oligonucleotide against SMAD7 mRNA, and inhibitors of leukocyte trafficking to intestinal sites of inflammation (e.g., sphingosine 1-phosphate receptor modulators). We also provide an update on the current status in clinical development of these new classes of therapeutics.

Biomarkers in Search of Precision Medicine in IBD

The completion of the human genome project in 2003 represented a major scientific landmark, ushering in a new era with hopes and expectations of fresh insights into disease mechanisms and treatments. In inflammatory bowel disease (IBD), many important discoveries soon followed, notably the identification of >200 genetic susceptibility loci and characterization of the gut microbiome. As "big data", driven by advances in technology, becomes increasingly available and affordable, individuals with IBD and clinicians alike yearn for tangible outcomes from the promise of "precision medicine"-precise diagnosis, monitoring, and treatment. Here, we provide a commentary on the prospects and challenges of precision medicine and biomarkers in IBD. We focus on the three key areas where precision IBD will have the most impact: (1) disease susceptibility, activity, and behavior; (2) prediction of drug response and adverse effects; and (3) identification of subphenotypic mechanisms to facilitate drug discovery and selection of new treatments in IBD.

Pharmacology and Optimization of Thiopurines and Methotrexate in Inflammatory Bowel Disease

Improving the efficacy and reducing the toxicity of thiopurines and methotrexate (MTX) have been areas of intense basic and clinical research. An increased knowledge on pharmacodynamics and pharmacokinetics of these immunomodulators has optimized treatment strategies in inflammatory bowel disease (IBD). This review focuses on the metabolism and mode of action of thiopurines and MTX, and provides an updated overview of individualized treatment strategies in which efficacy in IBD can be increased without compromising safety. The patient-based monitoring instruments adapted into clinical practice include pretreatment thiopurine S-methyltransferase testing, thiopurine metabolite monitoring, and blood count measurements that may help guiding the dosage to improve clinical outcome. Other approaches for optimizing thiopurine therapy in IBD include combination therapy with allopurinol, 5-aminosalicylates, and/or biologics. Similar strategies are yet to be proven effective in improving the outcome of MTX therapy. Important challenges for the management of IBD in the future relate to individualized dosing of immunomodulators for maximal efficacy with minimal risk of side effects. As low-cost conventional immunomodulators still remain a mainstay in pharmacotherapy of IBD, more research remains warranted, especially to substantiate these tailored management strategies in controlled clinical trials.

Crohn's Disease: Evolution, Epigenetics, and the Emerging Role of Microbiome-Targeted Therapies

Crohn's disease (CD) is a chronic, systemic, immune-mediated inflammation of the gastrointestinal tract. Originally described in 1932 as non-caseating granulomatous inflammation limited to the terminal ileum, it is now recognized as an expanding group of heterogeneous diseases defined by intestinal location, extent, behavior, and systemic extraintestinal manifestations. Joint diseases, including inflammatory spondyloarthritis and ankylosing spondylitis, are the most common extraintestinal manifestations of CD and share more genetic susceptibility loci than any other inflammatory bowel disease (IBD) trait. The high frequency and overlap with genes associated with infectious diseases, specifically Mendelian susceptibility to mycobacterial diseases (MSMD), suggest that CD may represent an evolutionary adaptation to environmental microbes. Elucidating the diversity of the enteric microbiota and the protean mucosal immune responses in individuals may personalize microbiome-targeted therapies and molecular classifications of CD. This review will focus on CD's natural history and therapies in the context of epigenetics, immunogenetics, and the microbiome.

Molecular Imaging in Preclinical Models of IBD with Nuclear Imaging Techniques: State-of-the-Art and Perspectives

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, is characterized by chronic unregulated inflammation of the intestinal mucosa of the gastrointestinal tract. To date, this pathology has no cure. Colonoscopy and biopsies are the current gold standard diagnostic tools. However, being a chronic disease, IBD requires continuous follow-up to check for disease progress, treatment response, and remission. Unfortunately, these 2 diagnostic procedures are invasive and generally unable to show the cellular and molecular changes that take place in vivo. In this context, it is clear that there is a strong need for optimized noninvasive imaging techniques able to overcome the aforementioned limitations. This review aims to bring to light the scientific advancements that have been achieved so far in nuclear medicine in relation to tracking of immune cells involved in the preclinical models of IBD. In particular, this review will explore the advantages and limitations of the radiopharmaceuticals that aim to track whole cells like neutrophils, those that involve the radiolabeling of immune cell substrates or available human IBD medical therapies, and those that aim to track cell signaling molecules (e.g., cytokines and cell adhesion molecules). After a detailed critical summary of the state-of-the art, the challenges and perspectives of molecular imaging applied to IBD studies will be analyzed. Special attention will be paid to the translational potential of the described techniques and on the potential impact of these innovative approaches on the drug discovery pipelines and their contribution to the evolution of personalized medicine.

Impact of Specialized Inpatient IBD Care on Outcomes of IBD Hospitalizations: A Cohort Study

BACKGROUND

The management of inflammatory bowel diseases (IBDs; Crohn's disease, ulcerative colitis) is increasingly complex. Specialized care has been associated with improved ambulatory IBD outcomes.

AIMS

To examine if the implementation of specialized inpatient IBD care modified short-term and long-term clinical outcomes in IBD-related hospitalizations.

METHODS

This retrospective cohort study included IBD patients hospitalized between July 2013 and April 2015 at a single tertiary referral center where a specialized inpatient IBD care model was implemented in July 2014. In-hospital medical and surgical outcomes as well as postdischarge outcomes at 30 and 90 days were analyzed along with measures of quality of in-hospital care. Effect of specialist IBD care was examined on multivariate analysis.

RESULTS

A total of 408 IBD-related admissions were included. With implementation of specialized IBD inpatient care, we observed increased frequency of use of high-dose biologic therapy for induction (26% versus 9%, odds ratio 5.50, 95% confidence interval 1.30-23.17) and higher proportion of patients in remission at 90 days after discharge (multivariate odds ratio 1.60, 95% confidence interval 0.99-2.69). Although there was no difference in surgery by 90 days, among those who underwent surgery, early surgery defined as in-hospital or within 30 days of discharge, was more common in the study period (71%) compared with the control period (46%, multivariate odds ratio 2.73, 95% confidence interval 1.22-6.12). There was no difference in length of stay between the 2 years.

CONCLUSIONS

Implementation of specialized inpatient IBD care beneficially impacted remission and facilitated early surgical treatment.

Optimizing Treatment with TNF Inhibitors in Inflammatory Bowel Disease by Monitoring Drug Levels and Antidrug Antibodies

BACKGROUND

Biological tumor necrosis factor (TNF) inhibitors have revolutionized the treatment of inflammatory bowel disease and redefined treatment goals to include mucosal healing. Clinicians are faced with challenges such as inadequate responses, treatment failures, side effects, and high drug costs. The objective is to review optimization of anti-TNF therapy by use of personalized treatment strategies based on circulating drug levels and antidrug antibodies (Abs), i.e. therapeutic drug monitoring (TDM). Furthermore, to outline TDM-related pitfalls and their prevention.

METHODS

Literature review.

RESULTS

Circulating anti-TNF drug trough level is a marker for the pharmacokinetics (PK) of TNF inhibitors. Because of a number of factors, including antidrug antibodies, PK varies between and within patients across time leading to variable clinical outcomes. Differences in intestinal inflammatory phenotype influencing the pharmacodynamic (PD) responses to TNF inhibitors also affect treatment outcomes. As an alternative to handling anti-TNF-treated patients by empiric strategies, TDM identifies underlying PK and PD-related reasons for treatment failure and aids decision making to secure optimal clinical and economic outcomes. Although promising, evidence does not the support use of TDM to counteract treatment failure in quiescent disease. Use of TDM is challenged by methodological biases, difficulties related to differentiation between PK and PD problems, and temporal biases due to lack of chronology between changes in PK versus symptomatic and objective disease activity manifestations. Biases can be accommodated by knowledgeable interpretation of results obtained by validated assays with clinically established thresholds, and by repeated assessments over time using complimentary techniques.

CONCLUSIONS

TDM-guided anti-TNF therapy at treatment failure has been brought from bench to bedside.

Endoscopy and cross-sectional imaging for assessing Crohn׳s disease activity

Crohn's disease (CD) is principally characterized by chronic and recurrent inflammation of the gastrointestinal tract, most commonly found in the ileo-colonic region. The chronicity and severity of intestinal inflammation together contribute to progressive, cumulative, deep, transmural intestinal damage, including stricturing, obstruction, abscesses, and fistulae. Both intestinal inflammation and its chronic complications result in a range of symptoms subsequently leading to patient presentations with diarrhea, abdominal pain, and anemia related to intestinal blood loss. Measuring disease activity and severity are essential for decision of treatment intensity early in the disease course and longitudinal monitoring of therapeutic efficacy. This review will summarize the transition from subjective symptoms driving disease activity indices, into increasingly objective and quantitative measures of intestinal injury by direct mucosal assessment (endoscopy), cross-sectional imaging, and surrogate biomarkers. Specific commentary on intestinal stricture and perianal fistula assessment and management are presented in accompanying sections of this series.

Fecal transplantation: any real hope for inflammatory bowel disease?

PURPOSE OF REVIEW

Fecal microbiota transplant (FMT) has emerged as an important treatment for antibiotic resistant or recurrent Clostridium difficile infection. There has been a great deal of media coverage of the efficacy of FMT, and patients with inflammatory bowel disease (IBD) understandably wonder if this approach would also work for them. There are also instructions on 'do it yourself' FMT therapy on the web. It is important to understand whether there is evidence that this approach is effective in IBD so that we can advise our patients appropriately.

RECENT FINDINGS

Systematic reviews have identified four case series involving 27 ulcerative colitis patients with a pooled remission rate of 24% (95% confidence interval (CI) = 11-45%). Two randomized controlled trials evaluating a total of 123 active ulcerative colitis patients have given conflicting results but the pooled data do suggest benefit with a number needed to treat of 6 (95% CI = 3-33). There are four case series involving 38 patients with Crohn's disease with a clinical response in 60.5% (95% CI = 28-86%). There are no randomized trials in Crohn's disease.

SUMMARY

At present there are insufficient data to recommend FMT in IBD, and patients certainly should not be administering this themselves. This remains an interesting approach to treating IBD and more studies are needed to establish the optimal method of delivery as well as randomized, placebo controlled trials to establish the efficacy of FMT.

Validation and Optimization of an Ex Vivo Assay of Intestinal Mucosal Biopsies in Crohn's Disease: Reflects Inflammation and Drug Effects

Crohn’s disease (CD) is a chronic illness demanding better therapeutics. The marketed biologics only benefit some patients or elicit diminishing effect over time. To complement the known methods in drug development and to obtain patient specific drug responses, we optimized and validated a known human explant method to test drug candidates and pathophysiological conditions in CD intestinal biopsies. Mucosal biopsies from 27 CD patients and 6 healthy individuals were collected to validate an explant assay test where the polarized tissue was cultured on a novel metal mesh disk, slightly immersed in medium imitating an air-liquid interphase. After culture in high oxygen for 24 hours with or without biological treatment in the medium, biopsy integrity and penetration of antibodies was measured by immunohistochemistry (IHC). Nine cytokines were quantified in the conditioned medium as a read-out for degree of inflammation in individual biopsies and used to evaluate treatment efficacy. The biopsies were well-preserved, showing few structural changes. IHC revealed tissue penetration of antibodies demonstrating ability to test therapeutic antibodies. The cytokine release to the medium showed that the assay can distinguish between inflammation states and then validate the known effect of two treatment biologics confirmed by a detection panel of five specific cytokines. Our data also suggest that the assay would be able to indicate which patients are responders to anti-TNF-α therapeutics, and which are non-responders. This study demonstrates this version of an ex vivo culture as a valid and robust assay to assess inflammation in mucosal biopsies and test of the efficacy of novel drug candidates and current treatments on individual patients–potentially for a personalized medicine approach.

Review article: recent advances in pharmacogenetics and pharmacokinetics for safe and effective thiopurine therapy in inflammatory bowel disease

BACKGROUND

Azathioprine and mercaptopurine have a pivotal role in the treatment of inflammatory bowel disease (IBD). However, because of their complex metabolism and potential toxicities, optimal use of biomarkers to predict adverse effects and therapeutic response is paramount.

AIM

To provide a comprehensive review focused on pharmacogenetics and pharmacokinetics for safe and effective thiopurine therapy in IBD.

METHODS

A literature search up to July 2015 was performed in PubMed using a combination of relevant MeSH terms.

RESULTS

Pre-treatment thiopurine S-methyltransferase typing plus measurement of 6-tioguanine nucleotides and 6-methylmercaptopurine ribonucleotides levels during treatment have emerged with key roles in facilitating safe and effective thiopurine therapy. Optimal use of these tools has been shown to reduce the risk of adverse effects by 3-7%, and to improve efficacy by 15-30%. For the introduction of aldehyde oxidase (AOX) into clinical practice, the association between AOX activity and AZA dose requirements should be positively confirmed. Inosine triphosphatase assessment associated with adverse effects also shows promise. Nucleoside diphosphate-linked moiety X-type motif 15 variants have been shown to predict myelotoxicity on thiopurines in East Asian patients. However, the impact of assessments of xanthine oxidase, glutathione S-transferase, hypoxanthine guanine phosphoribosyltransferase and inosine monophosphate dehydrogenase appears too low to favour incorporation into clinical practice.

CONCLUSIONS

Measurement of thiopurine-related enzymes and metabolites reduces the risk of adverse effects and improves efficacy, and should be considered part of standard management. However, this approach will not predict or avoid all adverse effects, and careful clinical and laboratory monitoring of patients receiving thiopurines remains essential.

A Saudi Gastroenterology association position statement on the use of tumor necrosis factor-alfa antagonists for the treatment of inflammatory bowel disease

The objective of this position statement from the Saudi Gastroenterology Association is to guide gastroenterologists on the use of tumor necrosis factor-alfa (TNF-α) antagonists for the treatment of the idiopathic inflammatory bowel diseases, Crohn's disease, and ulcerative colitis. In this article, we summarize the relevant literature regarding the safety and efficacy of TNF-α antagonists, highlight relevant safety concerns specific to the environment in Saudi Arabia, and provide specific recommendations for the use of these agents.

Failure of gastroenterologists to apply intestinal ultrasound in inflammatory bowel disease in the Asia-Pacific: a need for action

Intestinal ultrasound (IUS) is a cheap, noninvasive, risk-free procedure that is significantly underutilized in the diagnosis and management of patients with inflammatory bowel disease (IBD) in the Asia-Pacific region. More cost-effective methods of monitoring disease activity are required in light of the increasing global burden of IBD (especially in Asia), the advent of personalized medicine, and the rising cost of healthcare. IUS is a prime example of a technique that meets these needs. Its common clinical applications include assessing the activity and complications of IBD. In continental Europe, countries such as Germany and Italy use this imaging tool as the standard of care and have integrated it into management protocols. There are formal training programs in these countries to train gastroenterologists in IUS, and it is used in an outpatient setting during patient consultations. Barriers to its use in the Asia-Pacific region include lack of experience and research data, and there are few established centers with active training programs. These concerns can be addressed by investing more in IUS service provision and by increasing allocation of resources toward local research and training. Increased uptake of IUS will ultimately benefit patients with IBD.

[Reccomendations of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis (GETECCU) on the use of methotrexate in inflammatory bowel disease]

Methotrexate is an immunosuppressant that may be useful in several clinical scenarios in inflammatory bowel disease. In this article, we review the available evidence in Crohn's disease and ulcerative colitis and establish general recommendations for its use in clinical practice. Although the available data are limited, it is very likely that methotrexate is underused because its effectiveness is underestimated and its toxicity is overestimated. Both in induction therapy and in maintenance of remission, methotrexate is useful in Crohn's disease. When prescribed in combination with biologic agents, immunogenicity is less frequent and consequently long-term response could potentially be improved. There are few published studies, but several data suggest that methotrexate could also be useful in ulcerative colitis. Although myelotoxicity and liver toxicity are well known risks, methotrexate is a drug that is well tolerated in many patients, even in the long term.

Clinical phenotype network: the underlying mechanism for personalized diagnosis and treatment of traditional Chinese medicine

Traditional Chinese medicine (TCM) investigates the clinical diagnosis and treatment regularities in a typical schema of personalized medicine, which means that individualized patients with same diseases would obtain distinct diagnosis and optimal treatment from different TCM physicians. This principle has been recognized and adhered by TCM clinical practitioners for thousands of years. However, the underlying mechanisms of TCM personalized medicine are not fully investigated so far and remained unknown. This paper discusses framework of TCM personalized medicine in classic literatures and in real-world clinical settings, and investigates the underlying mechanisms of TCM personalized medicine from the perspectives of network medicine. Based on 246 well-designed outpatient records on insomnia, by evaluating the personal biases of manifestation observation and preferences of herb prescriptions, we noted significant similarities between each herb prescriptions and symptom similarities between each encounters. To investigate the underlying mechanisms of TCM personalized medicine, we constructed a clinical phenotype network (CPN), in which the clinical phenotype entities like symptoms and diagnoses are presented as nodes and the correlation between these entities as links. This CPN is used to investigate the promiscuous boundary of syndromes and the co-occurrence of symptoms. The small-world topological characteristics are noted in the CPN with high clustering structures, which provide insight on the rationality of TCM personalized diagnosis and treatment. The investigation on this network would help us to gain understanding on the underlying mechanism of TCM personalized medicine and would propose a new perspective for the refinement of the TCM individualized clinical skills.