Disease activity, ANCA, and IL23R genotype status determine early response to infliximab in patients with ulcerative colitis

Biomarkers for Personalizing IBD Therapy: The Quest Continues

Despite recent advances in the understanding of the pathogenesis of inflammatory bowel diseases (IBD) and advent of multiple targeted therapies, approximately one-third of patients are primary non-responders to initiated treatment, and half of patients lose response over time. There is currently a lack of available biomarkers that would prognosticate therapeutic effectiveness of these advanced therapies. This is partly explained by insufficient characterization of the functional roles assumed by the chosen molecular targets during disease treatment. There is a dire need for validated objective biomarkers, which could be indicators of a biological process, that can be applied in clinical practice to assist us in assigning therapies to patients with the highest probability of response. An appropriate molecular and cellular characterization that accounts for the interindividual differences in drug efficacy and potential side effects would help to guide clinicians in the management of patients with IBD and represent a major step to tailor a more personalized approach to treatment. An appropriate combination of complementing biomarkers should ideally incorporate a multimodal analysis in which genetic, microbial, transcriptional, proteomic, metabolic, and immunologic data are combined to enable a truly personalized approach. This would classify patients into disease subgroups according to molecular characteristics, which would enable us to initiate the most appropriate therapeutic substance. Emergence of single-cell technologies to map the intestinal cellular landscape and multiomic approaches have helped to further dissect the pathogenic mechanisms of mucosal inflammation, but the clinical translation of potential biomarkers remains cumbersome, and an ongoing concerted effort by the IBD community is required.

Therapeutic drug monitoring in inflammatory bowel diseases. Position statement of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis

The treatment of inflammatory bowel disease has undergone a significant transformation following the introduction of biologic drugs. Thanks to these drugs, treatment goals have evolved from clinical response and remission to more ambitious objectives, such as endoscopic or radiologic remission. However, even though biologics are highly effective, a significant percentage of patients will not achieve an initial response or may lose it over time. We know that there is a direct relationship between the trough concentrations of the biologic and its therapeutic efficacy, with more demanding therapeutic goals requiring higher drug levels, and inadequate exposure being common. Therapeutic drug monitoring of biologic medications, along with pharmacokinetic models, provides us with the possibility of offering a personalized approach to treatment for patients with IBD. Over the past few years, relevant information has accumulated regarding its utility during or after induction, as well as in the maintenance of biologic treatment, in reactive or proactive strategies, and prior to withdrawal or treatment de-escalation. The aim of this document is to establish recommendations regarding the utility of therapeutic drug monitoring of biologics in patients with inflammatory bowel disease, in different clinical practice scenarios, and to identify areas where its utility is evident, promising, or controversial.

Predictive biomarkers for anti-TNF alpha therapy in IBD patients

Inflammatory bowel disease (IBD) is a chronic gastrointestinal condition characterized by severe gut inflammation, commonly presenting as Crohn's disease, ulcerative colitis or categorized as IBD- unclassified. While various treatments have demonstrated efficacy in adult IBD patients, the advent of anti-TNF therapies has significantly revolutionized treatment outcomes and clinical management. These therapies have played a pivotal role in achieving clinical and endoscopic remission, promoting mucosal healing, averting disease progression, and diminishing the necessity for surgery. Nevertheless, not all patients exhibit positive responses to these therapies, and some may experience a loss of responsiveness over time. This review aims to present a comprehensive examination of predictive biomarkers for monitoring the therapeutic response to anti-TNF therapy in IBD patients. It will explore their limitations and clinical utilities, paving the way for a more personalized and effective therapeutic approach.

Cellular and Molecular Determinants of Biologic Drugs Resistance and Therapeutic Failure in Inflammatory Bowel Disease

The advent of biologic drugs has revolutionized the treatment of Inflammatory Bowel Disease, increasing rates of response and mucosal healing in comparison to conventional therapies by allowing the treatment of corticosteroid-refractory cases and reducing corticosteroid-related side effects. However, biologic therapies (anti-TNFα inhibitors, anti-α4β7 integrin and anti-IL12/23) are still burdened by rates of response that hover around 40% (in biologic-naïve patients) or lower (for biologic-experienced patients). Moreover, knowledge of the mechanisms underlying drug resistance or loss of response is still scarce. Several cellular and molecular determinants are implied in therapeutic failure; genetic predispositions, in the form of single nucleotide polymorphisms in the sequence of cytokines or Human Leukocyte Antigen, or an altered expression of cytokines and other molecules involved in the inflammation cascade, play the most important role. Accessory mechanisms include gut microbiota dysregulation. In this narrative review of the current and most recent literature, we shed light on the mentioned determinants of therapeutic failure in order to pave the way for a more personalized approach that could help avoid unnecessary treatments and toxicities.

Interleukin gene polymorphisms and alopecia areata: A systematic review and meta-analysis

BACKGROUND

Alopecia areata (AA) is an autoimmune disease which results in non-scarring hair loss on the scalp or any surface with hair. Several genetic polymorphisms of the interleukin genes have been linked with this disease but the results are inconsistent. This systematic review and meta-analysis were done to find the association between rs3118470, rs2275913, rs3212227, and rs10889677 of the IL2RA, IL17A, IL12B, and IL23R genes, respectively, of the interleukin family with alopecia areata.

METHODS

A comprehensive search for relevant research articles was conducted in Pubmed, Google Scholar, and Embase databases. Our search yielded 8 relevant articles with 1940 cases and 1788 controls. The odds ratio with 95% confidence intervals was calculated using fixed effect and random effect models. Heterogeneity was determined using the Q-test and I2 test. Publication bias was determined and funnel plots were used to adjust the odds ratio.

RESULTS

We found a significant risk effect for rs3118470 of the IL2RA gene with alopecia areata in the dominant model (CC + CT vs TT; OR = 1.54, 95% confidence interval = 1.05-2.26, P < .05, I2 = 69.03%) and homozygous model (CC vs TT; OR = 2.00, 95% confidence interval = 1.07-3.71, P < .05, I2 = 72.84%). For the other single nucleotide polymorphisms, we could not find any statistically significant association with the disease.

CONCLUSION

Our analysis showed that mutation of rs3118470 of IL2RA gene possesses a significant risk effect for alopecia areata. Future studies with larger sample sizes and ethnic backgrounds are warranted to confirm our findings.

Poor prognostic factors of pharmacokinetic origin predict outcomes in inflammatory bowel disease patients treated with anti-tumor necrosis factor-α

Introduction

We evaluated baseline Clearance of anti-tumor necrosis factors and human leukocyte antigen variant (HLA DQA1*05) in combination as poor prognostic factors (PPF) of pharmacokinetic (PK) origin impacting immune response (formation of antidrug antibodies) and disease control of inflammatory bowel disease (IBD) patients treated with infliximab or adalimumab.

Methods

Baseline Clearance was estimated in IBD patients before starting treatment using weight and serum albumin concentrations. HLA DQA1*05 carrier status (rs2097432 A/G or G/G variant) was measured using real time polymerase chain reaction. The outcomes consisted of immune response, clinical and biochemical remission (C-reactive protein<3 mg/L in the absence of symptoms), and endoscopic remission (SES-CD<3). Statistical analysis consisted of logistic regression and nonlinear mixed effect models.

Results and discussion

In 415 patients enrolled from 4 different cohorts (median age 27 [IQR: 15-43] years, 46% females), Clearance>0.326 L/day and HLA DQA1*05 carrier status were 2-fold more likely to have antidrug antibodies (OR=2.3, 95%CI: 1.7-3.4; p<0.001, and OR=1.9, 95%CI: 1.4-2.8; p<0.001, respectively). Overall, each incremental PPF of PK origin resulted in a 2-fold (OR=2.16, 95%CI: 1.7-2.7; p<0.11) [corrected] higher likelihood of antidrug antibody formation. The presence of both PPF of PK origin resulted in higher rates of antidrug antibodies (p<0.01) and lower clinical and biochemical remission (p<0.01). Each incremental increase in PPF of PK origin associated with lower likelihood of endoscopic remission (OR=0.4, 95%CI: 0.2-0.7; p<0.001). Prior biologic experience heightened the negative impact of PPF of PK origin on clinical and biochemical remission (p<0.01). Implementation of proactive therapeutic drug monitoring reduced it, particularly during maintenance and in the presence of higher drug concentrations (p<0.001). We conclude that PPF of PK origin, including both higher Clearance and carriage of HLA DQA1*05, impact outcomes in patients with IBD.

3D Printed Personalized Colon-targeted Tablets: A Novel Approach in Ulcerative Colitis Management

Ulcerative colitis (UC) and Crohn's disease (CD) are two types of idiopathic inflammatory bowel disease (IBD) that are increasing in frequency and incidence worldwide, particularly in highly industrialized countries. Conventional tablets struggle to effectively deliver anti-inflammatory drugs since the inflammation is localized in different areas of the colon in each patient. The goal of 3D printing technology in pharmaceutics is to create personalized drug delivery systems (DDS) that are tailored to each individual's specific needs. This review provides an overview of existing 3D printing processes, with a focus on extrusion-based technologies, which have received the most attention. Personalized pharmaceutical products offer numerous benefits to patients worldwide, and 3D printing technology is becoming more affordable every day. Custom manufacturing of 3D printed tablets provides innovative ideas for developing a tailored colon DDS. In the future, 3D printing could be used to manufacture personalized tablets for UC patients based on the location of inflammation in the colon, resulting in improved therapeutic outcomes and a better quality of life.

Precision medicine in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an incurable disease characterized by remission-relapse cycles throughout its course. Both Crohn's disease (CD) and ulcerative colitis (UC), the two main forms of IBD, exhibit tendency to develop complications and substantial heterogeneity in terms of frequency and severity of relapse, thus posing great challenges to the clinical management for IBD. Current treatment strategies are effective in different ways in induction and maintenance therapies for IBD. Recent advances in studies of genetics, pharmacogenetics, proteomics and microbiome provide a strong driving force for identifying molecular markers of prognosis and treatment response, which should help clinicians manage IBD patients more effectively, and then, improve clinical outcomes and reduce treatment costs of patients. In this review, we summarize and discuss precision medicine in IBD, focusing on predictive markers of disease course and treatment response, and monitoring indices during therapeutic drug monitoring.

Precision Medicine in Inflammatory Bowel Disease

Ulcerative colitis and Crohn's disease are traditionally defined as the two main subtypes of inflammatory bowel disease. However, a more recent view considers IBD as a spectrum of heterogeneous phenotypes with consistent differences in clinical presentation and behaviors, likely explained by differences in underlying pathogenetic mechanisms. The etiology is still elusive, and the suggested pathogenesis is a complex interplay among genetic predisposition and abnormal immune response at the mucosal intestinal level, activated by only partially identified environmental triggers leading to altered intestinal permeability and impaired handling of gut microbiota. The undeniable continuous progress of medical therapy with more frequent shifts from traditional to more advanced modalities also underlines the actual unmet needs. We are using medications with completely different mechanisms of action, with a lack of predictive factors of outcomes and response and still an unsatisfactory rate of success. In addition, we are missing still valuable and accurate markers to predict disease progression and severity in order to avoid under- or over-treatment. In such a complex scenario, it is undoubtful that the application of artificial intelligence and machine learning algorithms may improve the management and pave the way for precision and eventually personalized medicine in these patients; however, there are still several challenges that will be the focus of this review.

Predictors and optimal management of tumor necrosis factor antagonist nonresponse in inflammatory bowel disease: A literature review

Tumor necrosis factor-α (TNF-α) antagonists, the first biologics approved for treating patients with inflammatory bowel disease (IBD), are effective for the induction and maintenance of remission and significantly improving prognosis. However, up to one-third of treated patients show primary nonresponse (PNR) to anti-TNF-α therapies, and 23%-50% of IBD patients experience loss of response (LOR) to these biologics during subsequent treatment. There is still no recognized predictor for evaluating the efficacy of anti-TNF drugs. This review summarizes the existing predictors of PNR and LOR to anti-TNF in IBD patients. Most predictors remain controversial, and only previous surgical history, disease manifestations, drug concentrations, antidrug antibodies, serum albumin, some biologic markers, and some genetic markers may be potentially predictive. In addition, we also discuss the next steps of treatment for patients with PNR or LOR to TNF antagonists. Therapeutic drug monitoring plays an important role in treatment selection. Dose escalation, combination therapy, switching to a different anti-TNF drug, or switching to a biologic with a different mechanism of action can be selected based on the concentration of the drug and/or antidrug antibodies.

Spondyloarthritis with inflammatory bowel disease: the latest on biologic and targeted therapies

Spondyloarthritis (SpA) encompasses a heterogeneous group of chronic inflammatory diseases that can affect both axial and peripheral joints, tendons and entheses. Among the extra-articular manifestations, inflammatory bowel disease (IBD) is associated with considerable morbidity and effects on quality of life. In everyday clinical practice, treatment of these conditions requires a close collaboration between gastroenterologists and rheumatologists to enable early detection of joint and intestinal manifestations during follow-up and to choose the most effective therapeutic regimen, implementing precision medicine for each patient's subtype of SpA and IBD. The biggest issue in this field is the dearth of drugs that are approved for both diseases, as only TNF inhibitors are currently approved for the treatment of full-spectrum SpA-IBD. Janus tyrosine kinase inhibitors are among the most promising drugs for the treatment of peripheral and axial SpA, as well as for intestinal manifestations. Other therapies such as inhibitors of IL-23 and IL-17, phosphodiesterase 4 inhibitor, α4β7 integrin blockers and faecal microbiota transplantation seem to only be able to control some disease domains, or require further studies. Given the growing interest in the development of novel drugs to treat both conditions, it is important to understand the current state of the art and the unmet needs in the management of SpA-IBD.

The Role of IL-23 in the Pathogenesis and Therapy of Inflammatory Bowel Disease

Interleukin-23 (IL-23) is a proinflammatory cytokine produced mainly by macrophages and antigen-presenting cells (APCs) after antigenic stimulation. IL-23 plays a significant role as a mediator of tissue damage. Indeed, the irregularities in IL-23 and its receptor signaling have been implicated in inflammatory bowel disease. IL-23 interacts with both the innate and adaptive immune systems, and IL-23/Th17 appears to be involved in the development of chronic intestinal inflammation. The IL-23/Th17 axis may be a critical driver of this chronic inflammation. This review summarizes the main aspects of IL-23's biological function, cytokines that control cytokine production, effectors of the IL-23 response, and the molecular mechanisms associated with IBD pathogenesis. Although IL-23 modulates and impacts the development, course, and recurrence of the inflammatory response, the etiology and pathophysiology of IBD are not completely understood, but mechanism research shows huge potential for clinical applications as therapeutic targets in IBD treatment.

MIF Variant rs755622 Is Associated with Severe Crohn's Disease and Better Response to Anti-TNF Adalimumab Therapy

Crohn's disease (CD), rheumatoid arthritis, psoriatic arthritis and other inflammatory diseases comprise a group of chronic diseases with immune-mediated pathogenesis which share common pathological pathways, as well as treatment strategies including anti-TNF biologic therapy. However, the response rate to anti-TNF therapy among those diseases varies, and approximately one third of patients do not respond. Since pharmacogenetic studies for anti-TNF therapy have been more frequent for other related diseases and are rare in CD, the aim of our study was to further explore markers associated with anti-TNF response in other inflammatory diseases in Slovenian CD patients treated with the anti-TNF drug adalimumab (ADA). We enrolled 102 CD patients on ADA, for which the response was defined after 4, 12, 20 and 30 weeks of treatment, using an IBDQ questionnaire and blood CRP value. We genotyped 41 SNPs significantly associated with response to anti-TNF treatment in other diseases. We found novel pharmacogenetic association between SNP rs755622 in the gene MIF (macrophage migration inhibitory factor) and SNP rs3740691 in the gene ARFGAP2 in CD patients treated with ADA. The strongest and most consistent association with treatment response was found for the variant rs2275913 in gene IL17A (p = 9.73 × 10-3).

Precision medicine and drug optimization in adult inflammatory bowel disease patients

Inflammatory bowel diseases (IBD) encompass two main entities including ulcerative colitis and Crohn's disease. Although having a common global pathophysiological mechanism, IBD patients are characterized by a significant interindividual heterogeneity and may differ by their disease type, disease locations, disease behaviours, disease manifestations, disease course as well as treatment needs. Indeed, although the therapeutic armamentarium for these diseases has expanded rapidly in recent years, a proportion of patients remains with a suboptimal response to medical treatment due to primary non-response, secondary loss of response or intolerance to currently available drugs. Identifying, prior to treatment initiation, which patients are likely to respond to a specific drug would improve the disease management, avoid unnecessary side effects and reduce the healthcare expenses. Precision medicine classifies individuals into subpopulations according to clinical and molecular characteristics with the objective to tailor preventative and therapeutic interventions to the characteristics of each patient. Interventions would thus be performed only on those who will benefit, sparing side effects and expense for those who will not. This review aims to summarize clinical factors, biomarkers (genetic, transcriptomic, proteomic, metabolic, radiomic or from the microbiota) and tools that could predict disease progression to guide towards a step-up or top-down strategy. Predictive factors of response or non-response to treatment will then be reviewed, followed by a discussion about the optimal dose of drug required for patients. The time at which these treatments should be administered (or rather can be stopped in case of a deep remission or in the aftermath of a surgery) will also be addressed. IBD remain biologically complex, with multifactorial etiopathology, clinical heterogeneity as well as temporal and therapeutic variabilities, which makes precision medicine especially challenging in this area. Although applied for many years in oncology, it remains an unmet medical need in IBD.

Genetic association of IL2RA, IL17RA, IL23R, and IL31RA single nucleotide polymorphisms with alopecia areata

The signalling of cytokine receptors plays a crucial role in regulating tolerance and immunity. Impaired immunological processes result in autoimmune inflammation that target the hair follicles, causing many hair disorders, mainly alopecia areata (AA). Therefore, polymorphisms in cytokine receptor genes are suggested to have a significant impact on the pathogenesis of AA, a disease with a multifactorial basis and uncertain etiology. In the present study, 152 AA patients of the Jordanian population were investigated for their genetic susceptibility to develop AA compared to 150 control subjects. Genomic DNA extraction and genotyping had conducted for IL17RA (rs879575, rs2229151, and rs4819554), IL2RA (rs3118470), IL23R (rs10889677), and IL31RA (rs161704) using the Sequenom MassARRAY® system. The allele frequency of IL17RA rs879575 is significantly higher in patients, while no statistical differences were found for IL2RA, IL23R, and IL31RA SNPs. Also, the recessive model of IL31RA rs161704 showing that AA genotype is significantly associated with AA development. To date, there is no published data regarding the association between AA and the selected genetic variants in our population. However, this study's findings assert that SNPs of IL17RA and IL31RA are linked to AA susceptibility in Jordanian patients.

Development of a Machine Learning Model to Predict Non-Durable Response to Anti-TNF Therapy in Crohn’s Disease Using Transcriptome Imputed from Genotypes

Almost half of patients show no primary or secondary response to monoclonal anti-tumor necrosis factor α (anti-TNF) antibody treatment for inflammatory bowel disease (IBD). Thus, the exact mechanisms of a non-durable response (NDR) remain inadequately defined. We used our genome-wide genotype data to impute expression values as features in training machine learning models to predict a NDR. Blood samples from various IBD cohorts were used for genotyping with the Korea Biobank Array. A total of 234 patients with Crohn’s disease (CD) who received their first anti-TNF therapy were enrolled. The expression profiles of 6294 genes in whole-blood tissue imputed from the genotype data were combined with clinical parameters to train a logistic model to predict the NDR. The top two and three most significant features were genetic features (DPY19L3, GSTT1, and NUCB1), not clinical features. The logistic regression of the NDR vs. DR status in our cohort by the imputed expression levels showed that the β coefficients were positive for DPY19L3 and GSTT1, and negative for NUCB1, concordant with the known eQTL information. Machine learning models using imputed gene expression features effectively predicted NDR to anti-TNF agents in patients with CD.

Genetic association of primary nonresponse to anti-TNFα therapy in patients with inflammatory bowel disease

OBJECTIVES

Primary nonresponse (PNR) to antitumor necrosis factor-α (TNFα) biologics is a serious concern in patients with inflammatory bowel disease (IBD). We aimed to identify the genetic variants associated with PNR.

PATIENTS AND METHODS

Patients were recruited from outpatient GI clinics and PNR was determined using both clinical and endoscopic findings. A case-control genome-wide association study was performed in 589 IBD patients and associations were replicated in an independent cohort of 293 patients. Effect of the associated variant on gene expression and TNFα secretion was assessed by cell-based assays. Pleiotropic effects were investigated by Phenome-wide association study (PheWAS).

RESULTS

We identified rs34767465 as associated with PNR to anti-TNFα therapy (odds ratio: 2.07, 95% CI, 1.46-2.94, P = 2.43 × 10-7, [replication odds ratio: 1.8, 95% CI, 1.04-3.16, P = 0.03]). rs34767465 is a multiple-tissue expression quantitative trait loci for FAM114A2. Using RNA-sequencing and protein quantification from HapMap lymphoblastoid cell lines (LCLs), we found a significant decrease in FAM114A2 mRNA and protein expression in both heterozygous and homozygous genotypes when compared to wild type LCLs. TNFα secretion was significantly higher in THP-1 cells [differentiated into macrophages] with FAM114A2 knockdown versus controls. Immunoblotting experiments showed that depletion of FAM114A2 impaired autophagy-related pathway genes suggesting autophagy-mediated TNFα secretion as a potential mechanism. PheWAS showed rs34767465 was associated with comorbid conditions found in IBD patients (derangement of joints [P = 3.7 × 10-4], pigmentary iris degeneration [P = 5.9 × 10-4], diverticulum of esophagus [P = 7 × 10-4]).

CONCLUSIONS

We identified a variant rs34767465 associated with PNR to anti-TNFα biologics, which increases TNFα secretion through mechanism related to autophagy. rs34767465 may also explain the comorbidities associated with IBD.

Results of the Seventh Scientific Workshop of ECCO: Precision Medicine in IBD-What, Why, and How

Many diseases that affect modern humans fall in the category of complex diseases, thus called because they result from a combination of multiple aetiological and pathogenic factors. Regardless of the organ or system affected, complex diseases present major challenges in diagnosis, classification, and management. Current forms of therapy are usually applied in an indiscriminate fashion based on clinical information, but even the most advanced drugs only benefit a limited number of patients and to a variable and unpredictable degree. This 'one measure does not fit all' situation has spurred the notion that therapy for complex disease should be tailored to individual patients or groups of patients, giving rise to the notion of 'precision medicine' [PM]. Inflammatory bowel disease [IBD] is a prototypical complex disease where the need for PM has become increasingly clear. This prompted the European Crohn's and Colitis Organisation to focus the Seventh Scientific Workshop on this emerging theme. The articles in this special issue of the Journal address the various complementary aspects of PM in IBD, including what PM is; why it is needed and how it can be used; how PM can contribute to prediction and prevention of IBD; how IBD PM can aid in prognosis and improve response to therapy; and the challenges and future directions of PM in IBD. This first article of this series is structured on three simple concepts [what, why, and how] and addresses the definition of PM, discusses the rationale for the need of PM in IBD, and outlines the methodology required to implement PM in IBD in a correct and clinically meaningful way.

The Role of Biomarkers in Surgery for Ulcerative Colitis: A Review

Ulcerative colitis (UC) is an inflammatory condition that generally affects the rectum and extends proximally into the colon in a continuous, distal-to-proximal pattern. Surgical resection (total proctocolectomy) is the only cure for UC and is often necessary in managing complicated or refractory disease. However, recent advances in biologically targeted therapies have resulted in improved disease control, and surgery is required in only a fraction of cases. This ever-increasing array of options for medical management has added complexity to surgical decision-making. In some circumstances, the added time required to ensure failure of medical therapy can delay colectomy in patients who will ultimately need it. Indeed, many patients with severe disease undergo trials of multiple medical therapies prior to considering surgery. In severe cases of UC, continued medical management has been associated with a delay to surgical intervention and higher rates of morbidity and mortality. Biomarkers represent a burgeoning field of research, particularly in inflammatory bowel disease and cancer. This review seeks to highlight the different possible settings for surgery in UC and the role various biomarkers might play in each.

Serum PR3-ANCA Is a Predictor of Primary Nonresponse to Anti-TNF-α Agents in Patients with Ulcerative Colitis

Background

Anti-tumor necrosis factor-α (TNF-α) agents are effective for moderately to severely active ulcerative colitis (UC). Nonetheless, a proportion of patients fail to respond to these agents as therapy for induction of remission. Recent studies indicated that perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA) may predict response to anti-TNF-α agents in UC patients. However, whether PR3-ANCA can predict primary nonresponse (PNR) to anti-TNF-α agents has not yet been evaluated. The aim of this study was to examine whether PR3-ANCA can predict PNR to anti-TNF-α in UC patients.

Methods

This was a single-center retrospective study. Data were extracted from 50 patients with UC who had measurements of PR3-ANCA and received anti-TNF-α agents for the first time as induction therapy. The primary endpoint of this study was a proportion of patients with PNR stratified by PR3-ANCA positivity. PNR to anti-TNF-α agents was defined as failure to achieve reduction in partial Mayo score by 2 or more points and change to other therapeutics within 6 weeks.

Results

Fourteen (28%) of the 50 patients were PR3-ANCA positive. Seventeen (34%) of the 50 patients demonstrated PNR. Eleven (78.6%) of the 14 PR3-ANCA-positive patients demonstrated PNR, while 6 (16.7%) of the 36 PR3-ANCA-negative patients demonstrated PNR. Multivariate analysis demonstrated that PR3-ANCA positivity was associated with PNR to anti-TNF-α agents (odds ratio 19.29, 95% CI: 3.30-172.67; p = 0.002).

Conclusion

PR3-ANCA positivity can predict PNR to anti-TNF-α agents in UC patients.

Precision Medicine in Inflammatory Bowel Diseases

During the last decades, a better understanding of the mechanisms sustaining the pathogenic process in inflammatory bowel diseases (IBD) has contributed to expand the therapeutic armamentarium for patients with these disorders. Alongside with traditional therapies, monoclonal antibodies against tumor necrosis factor-α, the interleukin (IL)-12/IL-23 p40 subunit and the α4β7 integrin, and tofacitinib, a small molecule inhibiting intracellular pathways downstream to cytokine receptors, have entered into the clinic. However, these drugs are not effective in all patients and some responders can lose response over time. Such a therapeutic failure is, at least in part, dependent on the fact that, in IBD, the tissue damage is driven by simultaneous activation of multiple and distinct immune-inflammatory signals and the detrimental mucosal immune response changes over time even in the same patient. Therefore, personalized approaches aimed at identifying which patient should be treated with a specific drug at a precise time point are worth pursuing. A such approach has the advantage to improve efficacy of the drug and limit adverse reactions, thereby improving quality of the life of the patients and reducing costs. In this review, we summarize all the available evidence about the possible role of precision medicine in IBD.

Role of the IL23/IL17 Pathway in Crohn's Disease

Crohn's disease (CD) is a chronic relapsing disorder of the gastrointestinal tract and represents one of the main entities of inflammatory bowel disease (IBD). CD affects genetically susceptible patients that are influenced by environmental factors and the intestinal microbiome, which results in excessive activation of the mucosal immune system and aberrant cytokine responses. Various studies have implicated the pro-inflammatory cytokines IL17 and IL23 in the pathogenesis of CD. IL23 is a member of the IL12 family of cytokines and is able to enhance and affect the expansion of pathogenic T helper type 17 (Th17) cells through various mechanisms, including maintenance of Th17 signature genes, upregulation of effector genes or suppression of repressive factors. Moreover, IL17 and IL23 signaling is able to induce a cascade of pro-inflammatory molecules like TNF, IFNγ, IL22, lymphotoxin, IL1β and lipopolysaccharide (LPS). Here, IL17A and TNF are known to mediate signaling synergistically to drive expression of inflammatory genes. Recent advances in understanding the immunopathogenetic mechanisms underlying CD have led to the development of new biological therapies that selectively intervene and inhibit inflammatory processes caused by pro-inflammatory mediators like IL17 and IL23. Recently published data demonstrate that treatment with selective IL23 inhibitors lead to markedly high response rates in the cohort of CD patients that failed previous anti-TNF therapy. Macrophages are considered as a main source of IL23 in the intestine and are supposed to play a key role in the molecular crosstalk with T cell subsets and innate lymphoid cells in the gut. The following review focuses on mechanisms, pathways and specific therapies in Crohn's disease underlying the IL23/IL17 pathway.

Predictors and Early Markers of Response to Biological Therapies in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are chronic conditions that primarily affect the gastrointestinal tract, with a complex pathogenesis; they are characterized by a significant heterogeneity of clinical presentations and of inflammatory pathways that sustain intestinal damage. After the introduction of the first biological therapies, the pipeline of therapies for IBD has been constantly expanding, and a significant number of new molecules is expected in the next few years. Evidence from clinical trials and real-life experiences has taught us that up to 40% of patients do not respond to a specific drug. Unfortunately, to date, clinicians lack a valid tool that can predict each patient’s response to therapies and that could help them in choosing what drug to administer. Several candidate biomarkers have been investigated so far, with conflicting results: clinical, genetic, immunological, pharmacokinetic and microbial markers have been tested, but no ideal marker has been identified so far. Based on recent evidence, multiparametric models seemingly hold the greatest potential for predicting response to therapy. In this narrative review, we aim to summarize the current knowledge on predictors and early markers of response to biological therapies in IBD.

Targeting B cells for inflammatory bowel disease treatment: back to the future

B cells are critical to immune homeostasis at mucosal surfaces including those of the gastrointestinal tract. B cell-related abnormalities, comprising of a lympho-plasmacytic infiltrate, as well as anti-microbial antibodies, are well reported in patients with inflammatory bowel disease (IBD). However, B cell-targeting is not part of the therapeutic armamentarium in IBD. Recently, driven by the identification of genetic associations between IgG Fc receptors and IBD susceptibility, there has been renewed interest in defining the immunobiology of B cells during mucosal inflammation. Functional studies have demonstrated mechanisms of IgG-mediated disease pathogenesis and deep mucosal immunophenotyping using single cell RNA sequencing has elaborated a significant remodelling of the B cell compartment in IBD. In light of these novel data, here we discuss potential strategies to target B cell immunity in IBD. Finally, we discuss potential risks and pitfalls of these approaches and emphasize on distinguishing between homeostatic and pathological B cell signatures, allowing for a data-based, prudent therapeutic approach.

Endoscopic Activity and Serum TNF-α Level at Baseline Are Associated With Clinical Response to Ustekinumab in Crohn's Disease Patients

BACKGROUND AND AIMS

The therapeutic efficacy and safety of ustekinumab for Crohn's disease (CD) have been reported from randomized controlled trials and real-world data. However, there are few studies describing the identification of patients most suitable for ustekinumab therapy. The aim of this study was to prospectively evaluate the patients receiving ustekinumab and identify predictors of the treatment efficacy.

METHODS

Patients with moderate to severe active CD scheduled to receive ustekinumab were enrolled. The responders and nonresponders were compared at weeks 0, 8, 24, and 48 by evaluating patient demographics, simple endoscopic scores (SES-CD), ustekinumab and cytokine concentrations, and cellular fractions.

RESULTS

The clinical response and clinical remission rates in the 22 enrolled patients were 59.1% and 31. 8% at week 8, 68.2% and 45.5% at week 24, and 54.4% and 40.9% at week 48, respectively. There were no significant differences in patients' demographic and disease characteristics at baseline between responders and nonresponders. A combination of low SES-CD and high serum TNF-α concentration at baseline showed a good correlation with the clinical response. Serum TNF-α concentration was decreased because of the therapy. The ratio of CD4+TNF-α cells at baseline was significantly higher in responders than in nonresponders; however, the ratios of CD45+CD11b+TNF-α and CD45+CD11c+TNF-α cells were not different. The ratio of CD4+ TNF-α cells decreased with the treatment in the responders but not in the nonresponders.

CONCLUSIONS

The combination of 2 factors, namely higher serum TNF-α concentration and lower SES-CD at baseline, may assist clinicians in selecting the appropriate therapy for patients with moderate to severe CD.

Personalizing Treatment in IBD: Hype or Reality in 2020? Can We Predict Response to Anti-TNF?

The advent of anti-TNF agents as the first approved targeted therapy in the treatment of inflammatory bowel disease (IBD) patients has made a major impact on our existing therapeutic algorithms. They have not only been approved for induction and maintenance treatment in IBD patients, but have also enabled us to define and achieve novel therapeutic outcomes, such as combination of clinical symptom control and endoscopic remission, as well as mucosal healing. Nevertheless, approximately one third of treated patients do not respond to initiated anti-TNF therapy and these treatments are associated with sometimes severe systemic side-effects. There is therefore the currently unmet clinical need do establish predictive markers of response to identify the subgroup of IBD patients, that have a heightened probability of response. There have so far been approaches from different fields of IBD research, to descry markers that would empower us to apply TNF-inhibitors in a more rational manner. These markers encompass findings from disease-related and clinical factors, pharmacokinetics, biochemical markers, blood and stool derived parameters, pharmacogenomics, microbial species, metabolic compounds, and mucosal factors. Furthermore, changes in the intestinal immune cell composition in response to therapeutic pressure of anti-TNF treatment have recently been implicated in the process of molecular resistance to these drugs. Insights into factors that determine resistance to anti-TNF therapy give reasonable hope, that a more targeted approach can then be utilized in these non-responders. Here, IL-23 could be identified as one of the key factors determining resistance to TNF-inhibitors. Growing insights into the molecular mechanism of action of TNF-inhibitors might also enable us to derive critical molecular markers that not only mediate the clinical effects of anti-TNF therapy, but which level of expression might also correlate with its therapeutic efficacy. In this narrative review, we present an overview of currently identified possible predictive markers for successful anti-TNF therapy and discuss identified molecular pathways that drive resistance to these substances. We will also point out the necessity and difficulty of developing and validating a diagnostic marker concerning clinically relevant outcome parameters, before they can finally enter daily clinical practice and enable a more personalized therapeutic approach.

2020 international consensus on ANCA testing beyond systemic vasculitis

This document follows up on a 2017 revised international consensus on anti-neutrophil cytoplasm antibodies (ANCA) testing in granulomatosis with polyangiitis and microscopic polyangiitis and focuses on the clinical and diagnostic value of ANCA detection in patients with connective tissue diseases, idiopathic interstitial pneumonia, autoimmune liver diseases, inflammatory bowel diseases, anti-glomerular basement membrane (GBM) disease, infections, malignancy, and during drug treatment. Current evidence suggests that in certain settings beyond systemic vasculitis, ANCA may have clinical, pathogenic and/or diagnostic relevance. Antigen-specific ANCA targeting proteinase-3 and myeloperoxidase should be tested by solid phase immunoassays in any patient with clinical features suggesting ANCA-associated vasculitis and in all patients with anti-GBM disease, idiopathic interstitial pneumonia, and infective endocarditis associated with nephritis, whereas in patients with other aforementioned disorders routine ANCA testing is not recommended. Among patients with autoimmune liver diseases or inflammatory bowel diseases, ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1 who do not have conventional autoantibodies or in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn's disease. In these cases, ANCA should be tested by indirect immunofluorescence as the target antigens are not yet well characterized. Many questions concerning the optimal use of ANCA testing in patients without ANCA-associated vasculitis remain to be answered.

Predictors of Primary Response to Biologic Treatment [Anti-TNF, Vedolizumab, and Ustekinumab] in Patients With Inflammatory Bowel Disease: From Basic Science to Clinical Practice

BACKGROUND

Inflammatory bowel diseases [IBD]-ulcerative colitis and Crohn's disease-are commonly treated with biologic drugs. However, only approximately two-thirds of patients have an initial response to these therapies. Personalised medicine has the potential to optimise efficacy, decrease the risk of adverse drug events, and reduce costs by establishing the most suitable therapy for a selected patient.

AIM

The present study reviews the potential predictors of short-term primary response to biologic treatment, including not only anti-tumour necrosis factor [TNF] agents [such as infliximab, adalimumab, certolizumab, and golimumab] but also vedolizumab and ustekinumab.

METHODS

We performed a systematic bibliographical search to identify studies investigating predictive factors of response to biologic therapy.

RESULTS

For anti-TNF agents, most of the evaluated factors have not demonstrated usefulness, and many others are still controversial. Thus, only a few factors may have a potential role in the prediction of the response, including disease behaviour/phenotype, disease severity, C-reactive protein, albumin, cytokine expression in serum, previous anti-TNF therapy, some proteomic markers, and some colorectal mucosa markers. For vedolizumab, the availability of useful predictive markers seems to be even lower, with only some factors showing a limited value, such as the expression of α4β7 integrin in blood, the faecal microbiota, some proteomic markers, and some colorectal mucosa markers. Finally, in the case of ustekinumab, no predictive factor has been reported yet to be helpful in clinical practice.

CONCLUSION

In summary, currently no single marker fulfils all criteria for being an appropriate prognostic indicator of response to any biologic treatment in IBD.

Prognostic value of peri-nuclear Anti Neutrophil Cytoplasmic Antibodies in subjects with primary sclerosing cholangitis

OBJECTIVE

To evaluate the prognostic value of peri-nuclear Anti- Neutrophil Cytoplasmic Antibodies (p-ANCA) in subjects with primary sclerosing cholangitis (PSC) and in particular whether it is associated with inflammatory bowel disease (IBD).

PATIENTS AND METHODS

In the last 9 years,64 patientswere admitted to our Hospital with PSC: 34 males, mean age 53 years, range 17-90. All the patients had a cholestatic pattern of elevated serum enzymes. The diagnosis was made in most cases with magnetic resonance and in small percentages with endoscopic retrograde cholangiopancreatography (ERCP) or liver biopsy. In 33 patients with PSC, colonoscopy and p-ANCA assays were possible.

RESULTS

Thirteen patients showed p-ANCA positivity: 8 had ulcerative colitis (UC), with associated colon cancer (CC) in 3 cases, 3 had Crohn's disease (CD), 2 had no inflammatory bowel disease (IBD). Twenty patients were p-ANCA negative: only 1 with indeterminate IBD, while 19 had no IBD.

CONCLUSIONS

IBD, or especially UC, is present in85% of patients with CSP and p-ANCA positivity, whereas 95% of patients with PSC who test negative for p- ANCA do not have IBD.

Serum Biomarkers for Inflammatory Bowel Disease

Background: Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic, inflammatory disorder of the gastrointestinal tract. As the novel therapeutic goal and biologicals are widely recognized, accurate assessment of disease and prediction of therapeutic response have become a crucial challenge in clinical practice. Also, because of the continuously rising incidence, convenient and economical methods of diagnosis and clinical assessment are urgently needed. Recently, serum biomarkers have made a great progress and become a focus in IBD study because they are non-invasive, convenient, and relatively inexpensive than are markers in biopsy tissue, stool, breath, and other body fluids.

Aims: To review the available data on serological biomarkers for IBD.

Methods: We searched PubMed using predefined key words on relevant literatures of serum biomarkers regarding diagnosis, evaluation of therapeutic efficacy, surveillance of disease activity, and assessment of prognosis for IBD.

Results: We reviewed serological biomarkers that are well-established and widely used (e.g., C-reactive protein), newly discovered biomarkers (e.g., cytokines, antibodies, and non-coding RNAs), and also recently advancements in serological biomarkers (e.g., metabolomics and proteomics) that are used in different aspects of IBD management.

Conclusions: With such a wealth of researches, to date, there are still no ideal serum biomarkers for IBD. Serum profiling and non-coding RNAs are just starting to blossom but reveal great promise for future clinical practice. Combining different biomarkers can be valuable in improving performance of disease evaluation.

Interrogating host immunity to predict treatment response in inflammatory bowel disease

IBD treatment is undergoing a transformation with an expanding repertoire of drugs targeting different aspects of the immune response. Three novel classes of drugs have emerged in the past decade that target leukocyte trafficking to the gut (vedolizumab), neutralize key cytokines with antibodies (ustekinumab) and inhibit cytokine signalling pathways (tofacitinib). In advanced development are other drugs for IBD, including therapies targeting other cytokines such as IL-23 and IL-6. However, all agents tested so far are hampered by primary and secondary loss of response, so it is desirable to develop personalized strategies to identify which patients should be treated with which drugs. Stratification of patients with IBD by clinical parameters alone lacks sensitivity, and alternative modalities are now needed to deliver precision medicine in IBD. High-resolution profiling of immune response networks in individual patients is a promising approach and different technical platforms, including in vivo real-time molecular endoscopy, tissue transcriptomics and germline genetics, are promising tools to help predict responses to specific therapies. However, important challenges remain regarding the clinical utility of these technologies, including their scalability and accessibility. This Review focuses on unravelling some of the complexity of mucosal immune responses in IBD pathogenesis and how current and emerging analytical platforms might be harnessed to effectively stratify and individualise IBD therapy.

History of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the intestinal mucosa and unknown etiology. In this review, we identified three main eras in the IBD history. Between the 19th and the 20th century, the primary task had been the definition of the diagnostic criteria in order to differentiate the new entity from intestinal tuberculosis. In the 20th century, an intense and prolific therapeutic research prevailed, culminating in the introduction of biological drugs in the clinical setting. Since the beginning of the 21st century, traditional definition criteria have been challenged by holistic criteria in an effort to seek a still unattained cure. Centuries of worldwide efforts on IBD etiology and therapy search have culminated in this novel strategy.

Predictors of Flares in Infliximab-treated Children With Inflammatory Bowel Disease

One third of pediatric IBD patients who initially respond to infliximab (IFX) lose that response over time. This retrospective study, including 62 children treated with IFX from 2004 to 2017, aimed to identify factors associated with clinical flare. Ulcerative colitis, extreme body mass index, and lowest IFX trough levels were associated with clinical flare in the whole population. In Crohn disease patients, perianal disease was pejorative, while location proximal to ligament of Treitz was protective. Underweight patients probably correspond to the most severe cases who are more likely to relapse, with hypoalbuminemia responsible for lower systemic IFX availability. Obesity probably induces higher IFX clearance.

Pharmacogenetics: A strategy for personalized medicine for autoimmune diseases

For many years, a considerable number of patients with autoimmune diseases (ADs) have suffered from a lack of drug response and drug-related toxicity. Despite the emergence of new therapeutic options such as biological agents, patients continue to struggle with these problems. Unfortunately, new challenges, including the paradoxical effects of biological drugs, have complicated the situation. In recent decades, efforts have been made to predict drug response as well as drug-related side effects. Thanks to the many advances in genetics, evaluation of markers to predict drug response/toxicity before the initiation of treatment may be an avenue toward personalizing treatments. Implementing pharmacogenetics and pharmacogenomics in the clinic could improve clinical care; however, obstacles remain to effective personalized medicine for ADs. The present study attempted to clarify the concept of pharmacogenetics/pharmacogenomics for ADs. After an overview on the pathogenesis of the most common types of treatments, this paper focuses on pharmacogenetic studies related to the selected ADs. Bridging the gap between pharmacogenetics and personalized medicine is also discussed. Moreover, the advantages, disadvantages and recommendations related to making personalized medicine practical for ADs have been addressed.

Novel Genetic Risk Variants Can Predict Anti-TNF Agent Response in Patients With Inflammatory Bowel Disease

BACKGROUND

It is important to identify patients with inflammatory bowel disease [IBD] refractory to anti-tumour necrosis factor [TNF] therapy, to avoid potential adverse effects and to adopt different treatment strategies. We aimed to identify and validate clinical and genetic factors to predict anti-TNF response in patients with IBD.

MATERIALS AND METHODS

Mayo Clinic and Washington University IBD genetic association study cohorts were used as discovery and replicate datasets, respectively. Clinical factors included sex, age at diagnosis, disease duration and phenotype, disease location, bowel resection, tobacco use, family history of IBD, extraintestinal manifestations, and response to anti-TNF therapy.

RESULTS

Of 474 patients with IBD treated with anti-TNF therapy, 41 [8.7%] were refractory to therapy and 433 [91.3%] had response. Multivariate analysis showed history of immunomodulator use (odds ratio 10.2, p = 8.73E-4) and bowel resection (odds ratio 3.24, p = 4.38E-4) were associated with refractory response to anti-TNF agents. Among genetic loci, two [rs116724455 in TNFSF4/18, rs2228416 in PLIN2] were successfully replicated and another four [rs762787, rs9572250, rs144256942, rs523781] with suggestive evidence were found. An exploratory risk model predictability [area under the curve] increased from 0.72 [clinical predictors] to 0.89 after adding genetic predictors. Through identified clinical and genetic predictors, we constructed a preliminary anti-TNF refractory score to differentiate anti-TNF non-responders (mean [standard deviation] score, 5.49 [0.99]) from responders (2.65 [0.39]; p = 4.33E-23).

CONCLUSIONS

Novel and validated genetic loci, including variants in TNFSF, were found associated with anti-TNF response in patients with IBD. Future validation of the exploratory risk model in a large prospective cohort is warranted.

Impact of Genes and the Environment on the Pathogenesis and Disease Course of Inflammatory Bowel Disease

Crohn's disease and ulcerative colitis constitute two major subgroups of inflammatory bowel diseases (IBD), a group of complex polygenic diseases characterized by chronic and progressive inflammation in the gastrointestinal tract. In recent years, methodological advances in genetic analysis have greatly expanded our understanding of the genetic background of IBD. So far, more than 240 genetic risk loci have been identified for IBD. However, these risk alleles explain less than 30% of the susceptibility to disease development, suggesting that environmental factors contribute considerably. The increasing occurrence of IBD in Eastern countries following their 'westernization', as well as the increased risk of disease among those who migrate to high-incidence regions, also suggest that the environment is key in the pathogenesis of IBD. In this review, we summarize the current evidence on the role of genetic and environmental factors in the susceptibility to, and disease course of, IBD, and we suggest how these findings might be applied to clinical practice.

Comparative effectiveness of antitumour necrosis factor agents and vedolizumab in ulcerative colitis

INTRODUCTION

Antitumour necrosis factor (TNF) agents and vedolizumab are used to treat ulcerative colitis (UC) but the response is variable and there is little data on comparative effectiveness. Apart from previous exposure to anti-TNF agents, predictors of response have not been identified. We aimed to (i) compare the efficacy of anti-TNF agents and vedolizumab in UC and (ii) investigate the utility of clinical and biochemical parameters in predicting response.

PATIENTS AND METHODS

Patients commencing any biological therapy for ambulant UC were included. Disease activity was monitored serially with the Simple Clinical Colitis Activity Index for up to 12 months. We compared the efficacy of anti-TNF agents and vedolizumab for induction and maintenance of response and remission on an intention-to-treat basis. We examined the utility of faecal calprotectin (FC) and early normalization of FC to predict response.

RESULTS

Ninety-seven patients commencing anti-TNF and 42 commencing vedolizumab therapy were included. Vedolizumab-treated patients had significantly greater previous anti-TNF therapy exposure and a lower baseline FC. Response, remission and steroid-free remission rates were comparable between both groups at 6 weeks, 6 and 12 months. Clinical remission but not steroid-free remission at 12 months was higher in the vedolizumab group. There was a significant reduction in the Simple Clinical Colitis Activity Index and FC at 6 weeks, 6 and 12 months compared with baseline in both groups. Baseline FC and early normalization did not predict response at 6 and 12 months.

CONCLUSION

The efficacy of anti-TNF and vedolizumab in UC appear comparable. We could not identify any predictors of response and remission.

Expansion of IL-23 receptor bearing TNFR2+ T cells is associated with molecular resistance to anti-TNF therapy in Crohn's disease

OBJECTIVE

Anti-tumour necrosis factor (TNF) antibodies are successfully used for treatment of Crohn's disease. Nevertheless, approximately 40% of patients display failure to anti-TNF therapy. Here, we characterised molecular mechanisms that are associated with endoscopic resistance to anti-TNF therapy.

DESIGN

Mucosal and blood cells were isolated from patients with Crohn's disease prior and during anti-TNF therapy. Cytokine profiles, cell surface markers, signalling proteins and cell apoptosis were assessed by microarray, immunohistochemistry, qPCR, ELISA, whole organ cultures and FACS.

RESULTS

Responders to anti-TNF therapy displayed a significantly higher expression of TNF receptor 2 (TNFR2) but not IL23R on T cells than non-responders prior to anti-TNF therapy. During anti-TNF therapy, there was a significant upregulation of mucosal IL-23p19, IL23R and IL-17A in anti-TNF non-responders but not in responders. Apoptosis-resistant TNFR2+IL23R+ T cells were significantly expanded in anti-TNF non-responders compared with responders, expressed the gut tropic integrins α4β7, and exhibited increased expression of IFN-γ, T-bet, IL-17A and RORγt compared with TNFR2+IL23R- cells, indicating a mixed Th1/Th17-like phenotype. Intestinal TNFR2+IL23R+ T cells were activated by IL-23 derived from CD14+ macrophages, which were significantly more present in non-responders prior to anti-TNF treatment. Administration of IL-23 to anti-TNF-treated mucosal organ cultures led to the expansion of CD4+IL23R+TNFR2+ lymphocytes. Functional studies demonstrated that anti-TNF-induced apoptosis in mucosal T cells is abrogated by IL-23.

CONCLUSIONS

Expansion of apoptosis-resistant intestinal TNFR2+IL23R+ T cells is associated with resistance to anti-TNF therapy in Crohn's disease. These findings identify IL-23 as a suitable molecular target in patients with Crohn's disease refractory to anti-TNF therapy.

Genetic Studies of Inflammatory Bowel Disease-Focusing on Asian Patients

The pathogenesis of inflammatory bowel disease (IBD) is not well-understood; however, increased and persistent intestinal inflammation, due to inappropriate immune responses that are caused by interactions between genetic factors, gut microbiota, and environmental factors, are thought to lead to IBD. Various studies have identified more than 240 genetic variants related to IBD. These genetic variants are involved in innate and adaptive immunity, autophagy, defective bacterial handing, interleukin-23 and 10 signaling, and so on. According to several epidemiological and clinical studies, the phenotypes and clinical course of IBD differ between Asians and Europeans. Although the risk loci for IBD typically overlap between Asians and Westerners, genetic heterogeneity has been detected in many loci/genes, such as NOD2/CARD15, TNFSF15 and human leukocyte antigen, contributing to the risk of IBD. Thus, although common pathways exist between Westerners and Asians in the development of IBD, their significance may differ for individual pathways. Although genetic studies are not universally applicable in the clinical field, they may be useful for diagnosing and categorizing IBD, predicting therapeutic responses and toxicity to drugs, and assessing prognosis by risk modeling, thereby enabling precision medicine for individual patients.

Mechanisms of molecular resistance and predictors of response to biological therapy in inflammatory bowel disease

Biological therapy has led to marked improvements in treatment of patients with inflammatory bowel disease, and an increasing number of drugs has been approved for treatment. However, only a subgroup of patients responds to therapy, highlighting the need to identify biomarkers for therapeutic response to allow personalised medicine in inflammatory bowel disease. Potential markers of response to biological therapy have been identified; however, studies also suggest that changes in the composition of immune cell infiltrates in response to therapeutic pressure lead to molecular resistance to these drugs. For instance, the cytokine interleukin 23 has been identified as a driver of evasion of apoptosis in response to anti-tumour necrosis factor drugs in patients with Crohn's disease, leading to expansion of apoptosis-resistant T cells and drug resistance. In this Review, we examine the concept of molecular resistance to biological therapy and discuss implications for future therapy.

Multiple Cytokine Profiling: A New Model to Predict Response to Tumor Necrosis Factor Antagonists in Ulcerative Colitis Patients

BACKGROUND AND AIMS

Ulcerative colitis (UC) is a form of inflammatory bowel disease, and antibodies against tumor necrosis factor (anti-TNF) are used for treatment. Many patients are refractory or lose response to anti-TNF, and predicting response would be an extremely valuable clinical tool. Unlike most biomarkers, cytokines directly mediate inflammation, and their measurement may predict the likelihood of response or no response.

METHODS

Serum samples were obtained from 49 UC patients before infliximab infusions, and levels of 17 cytokines were measured using a multiplex assay. The Fisher linear discriminant analysis (FLDA) was applied to the cytokine values to predict which patients would respond to infliximab. "Response" was defined as clinical remission after the third infusion, and "no response" was defined as lack of remission after the third infusion.

RESULTS

The Fisher linear discriminant analysis model identified a subset of seven predictor cytokines: TNF-α, IL-12, IL-8, IL-2, IL-5, IL1-β, and IFN-γ. The obtained canonical coefficients enabled to calculate discriminant scores as linear combinations of the cytokines; model classified thepatients as responders and nonresponders with a sensitivity of 84.2% and a specificity of 93.3%. Overall, the yield of the FLDA model was 89.8% of the total 49 patients.

CONCLUSIONS

An unbiased, statistically derived, predictive model based on measurement of serum cytokines before therapy may predict a positive or negative outcome from the administration of anti-TNF to UC patients. Because accurately measuring cytokines is simple and inexpensive, the model may be a valuable new tool to complement other laboratory parameters used in the management of IBD patients.

Pharmacogenetics of treatments for inflammatory bowel disease

INTRODUCTION

Inflammatory bowel disease is a chronic inflammation of the gut whose pathogenesis is still unclear. Although no curative therapy is currently available, a number of drugs are used in induction and maintenance therapy; however, for most of these drugs, a high inter-individual variability in response is observed. Among the factors of this variability, genetics plays an important role. Areas covered: This review summarizes the results of pharmacogenetic studies, considering the most important drugs used and in particular aminosalycilates, glucocorticoids, thiopurines, monoclonal antibodies and thalidomide. Most studies used a candidate gene approach, even if significant breakthroughs have been obtained recently from applying genome-wide studies. When available, also investigations considering epigenetics and pharmacogenetic dosing guidelines have been included. Expert opinion: Only for thiopurines, genetic markers identified as predictors of efficacy or adverse events have allowed the development of dosing guidelines. For the other drugs, encouraging results are available and great expectations rely on the study of epigenetics and integration with pharmacokinetic information, especially useful for biologics. However, to improve therapy of IBD patients with these drugs, for implementation in the clinics of pharmacogenetics, informatic clinical decision support systems and training about pharmacogenetics of health providers are needed.

Systematic review: predictive biomarkers of therapeutic response in inflammatory bowel disease-personalised medicine in its infancy

BACKGROUND

Inflammatory bowel disease (IBD) is characterised by substantial heterogeneity in treatment response. With an expanding number of therapeutic agents, identifying optimal treatment at the patient level remains a major challenge.

AIM

To systematically review the available literature on predictive biomarkers of therapeutic response in IBD.

METHODS

An electronic literature search was performed on 30 January 2018 using MEDLINE, EMBASE and the Cochrane Library. Retrospective, prospective, uncontrolled and controlled studies reporting on biomarkers predicting therapeutic response in paediatric and adult IBD populations were eligible for inclusion. The methodological quality of the included studies was assessed using the QUIPS tool. Due to anticipated heterogeneity and limited data, a qualitative, rather than quantitative, assessment was planned.

RESULTS

Of the 10 638 citations identified, 92 articles met the inclusion criteria. Several potential DNA, mRNA and protein markers were evaluated as predictive biomarkers. Most studies focused on predicting response to anti-TNF agents. Substantial between-study heterogeneity was identified with respect to both the biomarkers studied and the definition of response. None of the included studies received a low risk of bias rating for all six domains. Currently, none of the biomarkers is sufficiently predictive for clinical use.

CONCLUSIONS

The search for predictive biomarkers is still in its infancy and current evidence is limited. Future research efforts should take into account the high patient heterogeneity within prospective trials with objective response assessment. Predictive models will most likely comprise a combination of several molecular markers from integrated omics-levels and clinical characteristics.

Use of biomarkers in inflammatory bowel disease

There are many useful biomarkers for initial diagnosis and the management of inflammatory bowel disease. Serologic biomarkers have been traditionally used because they are widely disposable, but recently faecal biomarkers, especially faecal calprotectin, have acquired great importance as they have shown to be more precise when establishing suspicion of the disease and also as predictors of mucosal healing or persistence of inflammatory activity. Faecal calprotectin is a good tool for predicting abnormal endoscopic studies, but has limited specificity because its levels can be altered in many digestive diseases presenting with similar symptoms. The precision of faecal calprotectin is higher when associated with other altered parameters, especially with C-reactive protein, or with clinical scores of inflammatory activity. Finally, there are many new generation serologic and faecal biomarkers. Despite there not being much evidence about these yet, some of them have shown promising results in different studies.

Molecular diagnosis and classification of inflammatory bowel disease

INTRODUCTION

Traditional diagnosis and classification of inflammatory bowel diseases (IBDs) have been based on clinical evaluation, laboratory testing, endoscopy, imaging, and histological examinations. With the advancement of medical technology, an increasing number of molecular surrogates are playing a key role in diagnosis, differential diagnosis, assessment of disease activity, prediction of clinical course, and therapeutic response of IBD. Areas covered: The authors review roles of both existing and emerging surrogates including genetic, serological, histologic, and fecal markers in diagnosis and classification of IBD. Comparisons in advantages and disadvantages of different markers have also been discussed. In addition, this review underscores controversial and unclear aspects which need further study. Expert commentary: IBD is characteristic of chronicity, relapse-remission and destructiveness. It is of great importance for clinicians to make an accurate diagnosis and classification. Current and new molecular markers perform well with acceptable sensitivity and specificity. The use of molecular markers in clinical practice needs to be further explored and then generalized. More work is warranted to identify novel useful markers and elucidate how to apply them together with current markers in clinical settings.

Genetic Markers Predict Primary Nonresponse and Durable Response to Anti-Tumor Necrosis Factor Therapy in Ulcerative Colitis

BACKGROUND

Despite a high nonresponse rate, predictors of response to anti-tumor necrosis factor (anti-TNF) therapy in ulcerative colitis (UC) remain limited. We aim to determine clinical and genetic predictors of primary nonresponse (PNR) and durable response (DR) to anti-TNF therapy in a large prospective UC cohort.

METHODS

Using the Illumina Immunochip, candidate polymorphisms associated with clinical outcomes of PNR and DR were separately evaluated and combined into weighted genetic risk scores. Combined genetic and clinical multivariable models for PNR and DR were compared with clinical predictive models using area under the receiver operating characteristic (AUROC) curves. Models were internally (DR) or externally (PNR) validated. Multivariable logistic regression was utilized to assess the association of genetic risk scores with infliximab levels and antibodies.

RESULTS

Of 231 patients, 28 (12%) experienced PNR and 120 (52%) experienced DR. There was no significant difference in clinical features between primary nonresponders and responders. Eight alleles were associated with PNR. A combined clinical-genetic model (AUROC, 0.87) more accurately predicted PNR compared with a clinical-only model (AUROC, 0.57; P < 0.0001). In an external cohort of 131 patients, increasing tertiles of PNR genetic risk score correlated with increased risk of PNR (P = 0.052). Twelve candidate loci were associated with DR. Genetic risk score quartiles for DR demonstrated a strong dose-response relationship in predicting treatment duration. Genetic risk scores for PNR and DR were not associated with infliximab levels or antibody formation.

CONCLUSION

Genetic polymorphisms enhance prediction of PNR and DR to anti-TNF therapy in patients with UC.

Serum interleukin-6 level is associated with response to infliximab in ulcerative colitis

OBJECTIVES

Infliximab is effective in patients with ulcerative colitis (UC); however, one-third of patients do not respond and require additional therapies such as other biologic agents. Therefore, the aim of this study was to analyze the association between pro-inflammatory molecules and clinical efficacy to elucidate possible mechanisms for the non-response to infliximab to aid in treatment selection.

MATERIALS AND METHOD

Patients with moderate-to-severe active UC receiving infliximab in our hospital between 2010 and 2016 for whom pre-treatment serum samples were available were retrospectively evaluated. We analyzed the association between serum interleukin (IL)-6, tumor necrosis factor-α (TNF-α) and soluble mucosal vascular addressin cell adhesion molecule-1 (sMAdCAM-1) and the clinical efficacy of infliximab. The primary endpoint was clinical response at the end of the induction period.

RESULTS

Forty-one patients were included in this study. After induction therapy, 27 patients (65.9%) showed a clinical response. Serum IL-6 levels were significantly lower in responders than in non-responders (p = .012), whereas no significant differences were noted in other factors including sMAdCAM-1 and TNF-α. Multivariate analysis identified that serum IL-6 level (odds ratio = 0.72; 95% confidence interval, 0.54-0.96; p = .027) was independently associated with response to infliximab.

CONCLUSIONS

Serum IL-6 level is associated with response to infliximab in UC. Elevated concentrations of IL-6 may provide insight to the mechanism of non-response to infliximab.

Indicators of suboptimal tumor necrosis factor antagonist therapy in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is refractory to treatment in one-half of patients.

AIMS

To evaluate the occurrence of suboptimal therapy among patients with IBD treated with tumor necrosis factor antagonists (anti-TNFs).

METHODS

A multinational chart review in Europe and Canada was conducted among IBD patients diagnosed with ulcerative colitis (UC) or Crohn's disease (CD) who initiated anti-TNF therapy between 2009 and 2013. The primary endpoint was the cumulative incidence of suboptimal therapy during a two-year follow-up period, defined by the presence of the following indicators: dose escalation, discontinuation, switching, non-biologic therapy escalation, or surgery.

RESULTS

The study included 1195 anti-TNF initiators (538 UC and 657 CD). The majority of patients (64% of UC and 58% of CD) had at least one indicator of suboptimal therapy. The median time to suboptimal therapy indicator was 12.5 and 17.5 months for UC and CD patients, respectively. Among the 111 UC and 174 CD anti-TNF switchers, 51% and 56% had an indicator of suboptimal therapy, respectively. The median time to suboptimal therapy indicator with the second anti-TNF was 14.3 and 13.0 months for UC and CD patients, respectively.

CONCLUSION

The majority of IBD patients showed suboptimal therapy with current anti-TNFs.