Α4β7 Integrin Research Articles

P019 GS-1069518 is a potent and selective small molecule α4β7 inhibitor

Abstract Background The interaction between the adhesion molecule MAdCAM-1 and the α4β7 integrin heterodimer enables the trafficking of gut-antigen specific lymphocytes to the small and large intestines and to gut-associated lymphoid tissues. The role of the α4β7 integrin in the pathophysiology of IBD has been clinically demonstrated, and targeted therapeutics have been shown to mitigate inflammation and mucosal damage mediated by α4β7+ lymphocytes. The purpose of this study was to determine the potency and selectivity of the small molecule α4β7 inhibitor GS-1069518. Methods The selectivity of GS-1069518 and relevant reference molecules was determined using in vitro cell capture assays with natural integrin ligands and by measuring receptor occupancy in human and cynomolgus monkey whole blood. The number of RPMI-8866 cells binding to MAdCAM-1-coated surfaces (a natural α4β7 ligand) and Jurkat cells binding to VCAM-1-coated surfaces (a natural α4β1 ligand) were quantified with high content imaging. Receptor occupancy on CD3+CD4+CD45RO+β7+ (human) or CD3+CD4+CD45RA-β7+ (cynomolgus monkey) and CD3+CD4+CD45RO+α4+β1+β7- (human) or CD3+CD4+CD45RA-α4+β1+β7- (cynomolgus monkey) memory T cells was measured by flow cytometry with fluorescent probes that detect occupancy in the ligand-binding sites. Results In a MAdCAM-1 cell capture assay, the EC50 of GS-1069518 was 0.034 nM, with 71-fold and >10,000-fold selectivity over α4β1 and αLβ2, respectively. In α4β7 receptor occupancy assays the EC50 of GS-1069518 was 0.36 nM in human whole blood and 0.4 nM in cynomolgus monkey whole blood. GS-1069518 was 482-fold selective for α4β7 over α4β1 in human whole blood and 119-fold selective for α4β7 in cynomolgus monkey blood. Conclusion GS-1069518 is a highly potent and selective small molecule inhibitor of the α4β7-MAdCAM-1 ligand binding interaction.

P003 Identification of an intestine-derived ex-Trm population in the blood of healthy individuals and patients with Inflammatory Bowel Disease

Abstract Background Tissue-resident memory T cells (Trm) persist in peripheral tissues and contribute to pathogen clearance and inflammation. Trm can re-enter the circulation (ex-Trm) and give rise to new effector and Trm populations. Skin-derived ex-Trm can be identified in human blood based on co-expression of the residency marker CD103 and cutaneous leukocyte antigen (CLA), a skin-tropism marker. The existence of ex-Trm derived from the gut would have implications for inflammatory bowel disease (IBD) and its treatment targeting the recruitment of circulating gut-homing cells. Methods Peripheral blood and colonic biopsies were taken from healthy volunteers and patients with IBD (Crohn’s disease or ulcerative colitis). PBMCs and cells isolated from biopsies by enzymatic digestion were analysed by multi-colour flow cytometry. Results More than 80% of colonic αβT cells were Trm, as defined by CD69 expression, in health and IBD; there was no significant increase in cells with a non-resident phenotype in inflamed tissue. Few CD4+ Trm co-expressed CD103. In contrast, CD8+ Trm comprised CD103+ and CD103- subsets, and CD69+CD103- cells were significantly reduced in IBD. Increased staining for KLRG1 and the cytotoxicity-associated protein perforin, indicated a more effector-like Trm phenotype in IBD. Putative gut-derived ex-Trm were identified amongst TCRαβ+CD45RA- blood cells as a β7++CD103+ population, indicative of cells expressing both α4β7 and CD103(α E)β7 integrin complexes. A separate CD103β7+α4β7 population defined by 1:1 expression of CD103 and β7 contained CLA+ skin ex-Trm. Gut ex-Trm comprised 0.3% of circulating CD8+ T cells (range 0.02–1.4%), and 1.2% of CD4+ T cells (range 0.3–3%). Gut and skin ex-Trm were phenotypically similar; both expressed the residency associated markers CD9 and CD101 but lacked CD69 expression. Gut ex-Trm were phenotypically distinct from both the traditional gut-trophic population (α4β7+CD103-CD45RA) and from naïve T cells. The proportion of gut ex-Trm did not differ between health and IBD. However, gut-derived ex-Trm were significantly reduced, relative to skin-derived ex-Trm, in Crohn’s disease, but not ulcerative colitis, when compared with health. Conclusion A putative gut-derived ex-Trm population can be identified in both healthy and IBD peripheral blood, with IBD-associated changes identified in this population and intestinal Trm. Circulating ex-Trm could link discreet areas of intestinal inflammation in Crohn’s disease and there is a selective loss of the gut ex-Trm population from the blood of these patients. The role of ex-Trm in IBD merits further study.

P022 Transcriptional biomarkers for vedolizumab therapy response in patients with moderate to severe Ulcerative Colitis

Abstract Background Vedolizumab is one of the current treatments for patients with Inflammatory Bowel Disease (IBD). The efficacy and safety, together with its gut specificity, make this drug an appealing therapeutic option for IBD patients with moderate to severe disease. However, as observed for other biologic treatments, a significant proportion of patients do not have an initial response to vedolizumab treatment. Currently, there is a lack of reliable biomarkers for vedolizumab treatment response, although this would help to palliate the socioeconomic costs derived from this disease. For that reason, the primary aim of this study is to establish the basis for the search of transcriptional factors associated with vedolizumab treatment response. Methods For the realization of this study, we collected blood samples from responder and non-responder Ulcerative Colitis (UC) patients treated with vedolizumab. The clinical response was measured using the Partial Mayo Score. The frequencies of different immune system populations were analysed by flow cytometry. Moreover, we measured the transcriptional levels of several genes in peripheral blood mononuclear cells (PBMC) by RT-qPCR. These experimental procedures were performed at baseline (T0) and after 14 weeks of follow-up (T14). Results We enrolled nine patients with an average age of 46.25±11.71, of which seven were previously treated with anti-TNF therapy. Our results show a specific pattern in responder and non-responder patients in the percentages of different innate and adaptive immune cell populations at T0 versus T14. Similarly, we observed a significant reduction in the expression of some chemokines (i.e., CCL25) and pro-resolutive factors (i.e., ANNEXIN A1) at T14 versus T0 in PBMCs from vedolizumab responder patients, which was not observed in non-responder patients. Conclusion Our data suggest that the frequencies of certain immune populations are associated with the response to vedolizumab treatment. In the same way, we found that specific transcripts are modulated in response to this α4β7 integrin antibodies in PBMCs. Therefore, we found a solid system to search for vedolizumab therapy response markers using low invasive techniques.

P722 Compositional differences of gut microbiome using taxonomic profiling in patients with ulcerative colitis after treatment with vedolizumab

Abstract Background Gut microbial dysbiosis has been suggested to contribute to pathogenesis of inflammatory bowel disease (IBD). Vedolizumab (VDZ), an α4β7 integrin blocker, has been used as an effective agent for patients with IBD. However, effect of VDZ on gut microbiome and its relationship with efficacy outcomes are still unclear. We investigated gut microbial change in patients with ulcerative colitis (UC) during VDZ treatment. Methods Patients with UC were prospectively enrolled and were given a 300 mg infusion of VDZ at weeks 0, 2, and 6 as an induction therapy and then every 8 weeks as a maintenance therapy. In cases of insufficient response, the interval of maintenance therapy was shortened to every 4 week infusion. Faecal samples were collected at weeks 0, 14, and 54 and 16S rRNA gene microbiome profiling analysis was performed. Clinical remission (CREM), clinical response (CRES), endoscopic mucosal healing (MH) and biochemical response (BioRES) were evaluated. Compositional differences in microbiome were analysed according to CREM, CRES, MH, and BioRES at weeks 0, 14, and 54. Results Faecal samples were collected from 27 patients and patients were classified according to their outcomes (Table 1). In the analyses regarding species richness (ACE, Chao1, Jackknife, The number of OTUs) and diversity indices (NPShannon, Shannon, Simpson, Phylogenetic Diversity), no significant difference was observed among groups at weeks 0, 14, and 54. There were no significant changes in microbial composition at week 14 and 54, respectively compared to basal level. However, compared to baseline, relative abundance of genus Prevotella showed significant differences between groups which achieved normalsation of C-reactive protein or not (p=0.0394) (Figure 1). In the linear discriminant analysis effect size (LEfSe) analysis, the genus Actinomyces and the species Actinomyces odontolyticus group increased in patients who had no response at efficacy outcomes (achievement of clinical remission, achievement of clinical response, achievement of endoscopic mucosal healing, normalisation of C-reactive protein, and normalisation of faecal calprotectin) at week 14, compared to week 0 (Fig 2A). The genus Clostridium_g24, the species Paraprevotella_uc and PAC001224_s were also significantly increased in the same patient group at week 54 (Fig 2B). Conclusion In UC patients treated with VDZ, microbial composition showed differences depending on the achievement of efficacy outcomes. Further studies regarding the causal relationship between microbial composition and outcomes are warranted with a larger number of patients.

P033 Single-cell analysis of gut mucosal- and peripheral blood cells in ulcerative colitis patients undergoing vedolizumab treatment

Abstract Background Vedolizumab (VDZ), a monoclonal antibody that targets α4β7 integrin, was approved to treat moderate-to-severe ulcerative colitis (UC) based on the presumption that it blocks T cell recruitment to the inflamed intestinal mucosa. The clinical evidence suggests that up to 50% of UC patients do not achieve disease remission under VDZ treatment. This study aims to identify changes in cell abundances and molecular pathways associated with VDZ response in UC. To this end, we included anti-tumor necrosis factor (anti-TNF)-naïve and anti-TNF-exposed patients with active UC, and utilized single-cell RNA sequencing (scRNAseq) and high-dimensional flow cytometry (Cytek) to assess the peripheral blood and the gut mucosal compartments. Methods Gut mucosal biopsies from inflamed and non-inflamed regions, and peripheral blood mononuclear cells (PBMCs) were obtained from UC patients 2 wks before (t0) and 14 wks after (t4) the start of VDZ administration. Response to treatment was prospectively evaluated based on endoscopic assessment (defined as a decrease in total Mayo score between t0 and t4) and physician global assessment (PGA) that incorporates disease activity score and biochemical measurements. Results A total of 25 UC patients (pts) were included: 44% anti-TNF-naïve. Endoscopic response to VDZ was observed in 32% of UC pts, while 56% of pts showed response based on PGA. The VDZ response rate (by PGA) was higher in anti-TNF-naïve pts vs anti-TNF-exposed pts (82% vs 36% responders, respectively). A preliminary analysis was performed on samples from 8 (out of 25) UC pts, profiling >70,000 gut mucosal cells and >25,000 PBMCs. Within the mucosal compartment, at t0 we identified immune cells (50% of all captured cells), stromal cells (10%), and epithelial cells (40%). Upon inflammation, the proportion of immune cells increased to 70%, stromal cells to 20%, while epithelial cells depleted to 10%. Notably, all main identified immune cell lineages – T cells, B cells and myeloid cells – contributed to the expansion of the immune cell compartment in inflamed mucosa. In line with scRNAseq data, we identified all major immune cell populations and detected expression of both the classic gut-directed and the redundant trafficking integrins by Cytek. Conclusion The preliminary results substantiate our current understanding of VDZ biology in UC. We confirm that anti-TNF-naïve pts have a higher response rate to VDZ vs anti-TNF-exposed pts. With this unique cohort, our study has the power to further explore molecular mechanisms and pathways that underlie VDZ response at the single-cell level.

DOP15 Fluorescent labelled vedolizumab for real-time visualization and quantification of local drug distribution and pharmacodynamics in Inflammatory Bowel Diseases during endoscopy

Abstract Background Vedolizumab is a monoclonal antibody which blocks integrin α4β7 inhibiting trafficking of T-lymphocytes into the gut. Unfortunately, up to 60% of vedolizumab patients experience non-response. The mechanism of action of vedolizumab is not elucidated, predictors of response are unknown and data for local drug distribution in the gut are lacking. In this clinical trial, we investigated the feasibility of assessing local distribution of fluorescently labelled vedolizumab in the gut mucosa of inflammatory bowel diseases (IBD) patients to finally enable prediction of therapy response in individual patients. Methods Vedolizumab (Entyvio, Takeda Pharma) was labelled to IRDye 800CW under cGMP conditions to yield clinical grade vedolizumab-800CW. In this dose-escalation trial, vedolizumab naïve IBD patients and IBD patients treated with vedolizumab for at least 14 weeks were included. Patients received an intravenous dose of fluorescently labelled vedolizumab of either 0 mg, 4.5 mg, 15 mg or 15 mg + 75 mg unlabelled vedolizumab 3 days prior colonoscopy. In vivo fluorescence imaging was assessed by fibre-based wide-field fluorescence molecular endoscopy (FME) and quantified by spectroscopy in healthy, mildly inflamed and severely inflamed tissue. All assessed tissue was biopsied for ex vivo examination of the fluorescent signal, fluorescence microscopy and spectroscopy. Results Up to submission 34 patients completed tracer injection and FME. An interim analysis was performed after 20 patients (5 in each dose group), which showed in severely inflamed tissue an 8 fold higher fluorescent signal in the 15 mg dose group (0.049 Q*μfa,x [mm-1]) compared to the control group (0.006 μfa,x [mm-1]) (p<0.05). Furthermore, the fluorescent signal within the 15 mg dose group was also 2.5 fold higher compared to healthy tissue (0.019 Q*μfa,x [mm-1]) (p<0.05).The addition of unlabelled vedolizumab gave similar results to the 15 mg group (p>0.99), suggesting that the drug target was still not saturated. The optimal dosage group of 15 mg was expanded up to 18 IBD patients, amongst them 6 IBD patients after 14 weeks of treatment regimen. Fluorescence microscopy showed clustering of fluorescent signals especially in inflamed mucosa. Additional experiments to detect vedolizumab target cells are ongoing. Conclusion In vivo visualization of fluorescent vedolizumab revealed a clear dose-dependent correlation between mucosal drug concentrations and the severity of mucosal inflammation. Fluorescence molecular endoscopy is a promising novel tool to get insight in drug distribution in IBD, detect target cells, assess target engagement and possibly predict therapy response in individual patients.

P039 The role of α4β7+CLA+ ‘dual tropic’ T cells in inflammatory bowel disease

Abstract Background Upon activation, T cells upregulate cell-surface molecules that enable entry into peripheral tissues. Retinoic acid (RA) produced by gut DC induces integrin α4β7 required for gut homing and represses CLA which facilitates skin entry; hence, these markers are usually reciprocally expressed. We aimed to identify the mechanisms enabling dual tropism, define the properties of α4β7+CLA+ T cells and compare blood and intestinal α4β7+CLA+ T cells in health and IBD. Methods Using flow cytometry, expression of α4β7 and CLA was assessed on (i) ex vivo human T cells from blood and intestinal tissue and; (ii) naïve CD4 T cells stimulated in vitro with antibodies (anti-CD3/28/2), or allogeneic DCs. The role of RA signalling and p38MAPK in CLA expression were investigated with respective antagonists Ro41-5253 and SB203580. Transwell studies were used to investigate whether DC-T cell direct contact was required for CLA expression. Single cell RNA sequencing (scRNAseq) of in vitro activated T cells was undertaken, with feature barcode antibody labelling of β7 and CLA. Differential gene expression and pathway analysis was undertaken. Results DC-activated T cells contained both α4β7+ and CLA+ cells and included a dual tropic population co-expressing both markers. In contrast, antibody-activated T cells expressed α4β7 but did not express CLA unless RA receptor alpha (RARa) signalling was also inhibited. The DC-derived signals that allowed CLA expression were partially dependent on p38MAPK and required DC-T cell contact for optimal activity. A high frequency of dual tropic T cells produced IFNg or TNFa. ScRNAseq identified 270 genes differentially expressed (fold change <-2 or >+2, FDR<0.01) between α4β7+CLA+ and α4β7+CLA- T populations generated by DC stimulation. Expression of FUT7, a fucosyltransferase implicated in generation of the CLA moiety, was increased in the α4β7+CLA+ population and overall 27 pathways were significantly enriched (p<0.05) in this population, including intestinal immune networks and IBD. Ex vivo, CD4+ and CD8+ dual tropic T cells were found in peripheral blood and intestinal tissue. CD4+ dual tropic T cells were significantly increased in the colon of patients with IBD (p=0.03). Conclusion DC-derived signals acting via p38MAPK generate pro-inflammatory dual tropic T cells even in the presence of active RA signalling. CLA expression may act as an additional ligand in gut trafficking by binding to selectins on the inflamed vascular endothelium and has a potential role in both gut and skin inflammation in IBD.

Comparative effectiveness of a second-line biologic in patients with ulcerative colitis: vedolizumab followed by an anti-TNF versus anti-TNF followed by vedolizumab

BackgroundSequential drug treatment with biological agents in ulcerative colitis (UC) is becoming increasingly complex. There are few studies comparing head-to-head outcomes in second-line treatments. The study assesses whether using anti-tumour...

Vedolizumab blocks α4β7 integrin-mediated T cell adhesion to MAdCAM-1 in microscopic colitis.

Background:In Crohn’s disease and ulcerative colitis, the anti-α4β7 integrin antibody vedolizumab has demonstrated efficacy in phase III trials and has been successfully used under real-world conditions. Occasionally, it has also been used in other forms of inflammatory bowel disease (IBD) such as microscopic colitis (MC). However, the mechanisms of vedolizumab in MC have not been studied to date. Therefore, we aimed to investigate the expression and functional role of gut-homing integrins and in particular α4β7 integrin in a cohort study in MC.Methods:We studied the expression of gut homing integrins on T cells from patients with MC and healthy controls by flow cytometry. To investigate the function of α4β7 integrin in MC and the potential of vedolizumab to block it, we used dynamic adhesion assays and transmigrations assays. Moreover, we describe two clinical cases of MC patients treated with vedolizumab.Results:A specific profile of gut homing markers can be found on T cells from patients with MC. α4β7 integrin functionally leads to firm adhesion to MAdCAM-1 and supports transmigration. Vedolizumab is able to block both processes. In two cases of MC, we observed reduced clinical symptoms and histologic improvement upon therapy with vedolizumab.Conclusion:Our data suggest that α4β7 mediates gut homing of T cells also in MC and that, on single cell level, vedolizumab blocks the function of α4β7 in MC. Thus, we provide mechanistic evidence supporting vedolizumab as promising therapeutic option for MC.

The Omentum in Obesity-Associated Cancer: A Hindrance to Effective Natural Killer Cell Migration towards Tumour Which Can Be Overcome by CX3CR1 Antagonism.

Simple SummaryOesophagogastric adenocarcinomas (OAC) are cancers of the food pipe and stomach which have a strong link with obesity. Natural killer (NK) cells are assassins of the immune system and are crucial for eliminating cancer. We have shown previously that NK cells are pulled into fat in OAC patients by a signalling protein called fractalkine (CX3CL1). Once in fat, NK cells die or are profoundly altered. This diminishes their ability to kill the tumour. We report that exposure to fat can reduce movement of NK cells towards the tumour. However, if a drug called a CX3CR1 antagonist is used to antagonise the receptor for fractalkine, we can restore NK cell movement towards the tumour. When we activate NK cells with a protein called IL-15, fractalkine can reduce its effect on NK cells. This provides further evidence for using CX3CR1 antagonists to reduce NK cell migration to fat and boost NK cell movement to the tumour.Oesophagogastric adenocarcinomas (OAC) are obesity-associated malignancies, underpinned by severe immune dysregulation. We have previously shown that natural killer (NK) cells preferentially migrate to OAC omentum, where they undergo phenotypic and functional alterations and apoptosis. Furthermore, we have identified the CX3CR1:fractalkine (CX3CL1) pathway as pivotal in their recruitment to omentum. Here, we elucidate whether exposure to the soluble microenvironment of OAC omentum, and in particular fractalkine and IL-15 affects NK cell homing capacity towards oesophageal tumour. Our data uncover diminished NK cell migration towards OAC tumour tissue conditioned media (TCM) following exposure to omental adipose tissue conditioned media (ACM) and reveal that this migration can be rescued with CX3CR1 antagonist E6130. Furthermore, we show that fractalkine has opposing effects on NK cell migration towards TCM, when used alone or in combination with IL-15 and uncover its inhibitory effects on IL-15-mediated stimulation of death receptor ligand expression. Interestingly, treatment with fractalkine and/or IL-15 do not significantly affect NK cell adhesion to MAdCAM-1, despite changes they elicit to the expression of integrin α4β7. This study provides further evidence that CX3CR1 antagonism has therapeutic utility in rescuing NK cells from the deleterious effects of the omentum and fractalkine in OAC, thus limiting their dysfunction.

Human influenza virus challenge identifies cellular correlates of protection for oral vaccination

Developing new influenza vaccines with improved performance and easier administration routes hinges on defining correlates of protection. Vaccine-elicited cellular correlates of protection for influenza in humans have not yet been demonstrated. A phase-2 double-blind randomized placebo and active (inactivated influenza vaccine) controlled study provides evidence that a human-adenovirus-5-based oral influenza vaccine tablet (VXA-A1.1) can protect from H1N1 virus challenge in humans. Mass cytometry characterization of vaccine-elicited cellular immune responses identified shared and vaccine-type-specific responses across B and Tcells. For VXA-A1.1, the abundance of hemagglutinin-specific plasmablasts and plasmablasts positive for integrin α4β7, phosphorylated STAT5, or lacking expression of CD62L at day 8 were significantly correlated with protection from developing viral shedding following virus challenge at day 90 and contributed to an effective machine learning model of protection. These findings reveal the characteristics of vaccine-elicited cellular correlates of protection for an oral influenza vaccine.

Circulating MAdCAM-1 and ITGB7 in Patients with Plaque Psoriasis and Eruptive Lichen Planus-Preliminary Data.

Simple SummaryPsoriasis and lichen planus are common skin diseases which have similar clinical presentation and pathogenesis. Considering these dermatoses are frequent and decrease patients’ life quality, it is important to look for different markers indicating patients’ condition which can possibly affect the choice of the treatment. MAdCAM-1 and ITGB7 molecules and their serum levels in patients with psoriasis and lichen planus have never been studied before; therefore, we are the first trying to analyze it in order to develop the current state of knowledge on psoriasis and lichen planus to better help patients.Plaque psoriasis (PSO) and lichen planus (LP) are skin diseases with some similarities in pathogenesis, comorbidities, and clinical presentation. Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) and its ligand, α4β7 integrin, are involved in inflammatory bowel diseases and liver dysfunctions, which occur more frequently in PSO and LP. Serum MAdCAM-1 and ITGB7 levels in patients with plaque PSO and eruptive LP have never been studied before. The study included 42 patients with PSO, 13 with LP, and 23 controls. Serum molecules levels were evaluated using the immune–enzymatic method. ITGB7 concentration was not statistically different, both in patients with PSO and LP, compared to controls (both p > 0.05). MAdCAM-1 level was significantly lower in PSO subjects than in controls (p = 0.041), whereas in the LP group, a downward trend was observed (p = 0.088) with p = 0.0455 in ANOVA. Multiple linear regression revealed independent associations between ITGB7 and HDL and BMI and RBC in the LP group. In psoriatic patients with elevated CRP, there was an upward trend for MAdCAM-1, and also a positive correlation between MAdCAM-1 and WBC. ITGB7 and MAdCAM-1 cannot serve as markers of disease activity or liver pathology neither in patients with PSO nor LP. MAdCAM-1 might play a role as an inflammation indicator in PSO and a beneficial influence on the lipid profile in LP.

Endoscopy as a Diagnostic Tool for Personalized Therapy in IBD: Prediction of Response to Biological Therapy.

Both Crohnʼs disease [1] and ulcerative colitis [2] are chronic relapsing disorders of the gastrointestinal tract that are characterized pathologically by intestinal inflammation. Both inflammatory bowel disease (IBD) entities are progressive conditions that can lead to bowel damage and disability, having a major impact on an individualʼs quality of life. Furthermore, ongoing inflammatory activity is causative for occurrence of strictures, fistula, abscesses, as well as heightened incidence of colitis-associated neoplasia. Optimized anti-inflammatory therapy is therefore essential in the management of IBD patients [1], [2]. Advances in understanding the underlying immunopathogenesis in ulcerative colitis have led to the development of biological therapies, which selectively inhibit crucial pathways of involved inflammatory processes. Blockade of the pro-inflammatory cytokine tumor necrosis factor (TNF) by neutralizing antibodies was the first approved treatment modality, which was complemented by the anti-adhesion antibody vedolizumab directed against the α4β7 integrin. Subsequently, the anti-IL-12/IL-23p40 antibody ustekinumab and the JAK-inhibitor tofacitinib have broadened our therapeutic armamentarium. In spite of their effectiveness, it was found that only subgroups of IBD patients benefit from these therapies. Depending on the duration and the clinical endpoints chosen, only 30 – 60% of patients will show an improvement of active disease. There is therefore the currently unmet clinical need to predict therapeutic responses prior to the initiation of therapy. Reliable prediction would enable the treating physician to directly introduce the patient to the most efficient therapy, which would enable time-efficient control of the disease and prevent the onset of irreversible structural damage. This would also be essential to avoid exposure of patients to associated potential side effects of an inefficient therapy and reduce the substantial costs of an inappropriate therapy for the health care systems [3].

Regulation and Role of αE Integrin and Gut Homing Integrins in Migration and Retention of Intestinal Lymphocytes during Inflammatory Bowel Disease.

Targeting interactions between α4β7 integrin and endothelial adhesion molecule MAdCAM-1 to inhibit lymphocyte migration to the gastrointestinal tract is an effective therapy in inflammatory bowel disease (IBD). Following lymphocyte entry into the mucosa, a subset of these cells expresses αEβ7 integrin, which is expressed on proinflammatory lymphocytes, to increase cell retention. The factors governing lymphocyte migration into the intestinal mucosa and αE integrin expression in healthy subjects and IBD patients remain incompletely understood. We evaluated changes in factors involved in lymphocyte migration and differentiation within tissues. Both ileal and colonic tissue from active IBD patients showed upregulation of ICAM-1, VCAM-1, and MAdCAM-1 at the gene and protein levels compared with healthy subjects and/or inactive IBD patients. β1 and β7 integrin expression on circulating lymphocytes was similar across groups. TGF-β1 treatment induced expression of αE on both β7+ and β7- T cells, suggesting that cells entering the mucosa independently of MAdCAM-1/α4β7 can become αEβ7+ ITGAE gene polymorphisms did not alter protein induction following TGF-β1 stimulation. Increased phospho-SMAD3, which is directly downstream of TGF-β, and increased TGF-β-responsive gene expression were observed in the colonic mucosa of IBD patients. Finally, in vitro stimulation experiments showed that baseline β7 expression had little effect on cytokine, chemokine, transcription factor, and effector molecule gene expression in αE+ and αE- T cells. These findings suggest cell migration to the gut mucosa may be altered in IBD and α4β7-, and α4β7+ T cells may upregulate αEβ7 in response to TGF-β once within the gut mucosa.

Low immunogenicity of vedolizumab determined by a simple drug-tolerant assay in patients with ulcerative colitis.

Vedolizumab is a humanized monoclonal antibody against the α4β7 integrin and is approved for treatment of inflammatory bowel diseases. In this study, we evaluated the immunogenicity of vedolizumab using a simple drug-tolerant assay developed in our laboratory. Serum vedolizumab trough levels and anti-vedolizumab antibody (AVA) levels were measured using new immunoassays in 37 patients with ulcerative colitis (UC) under vedolizumab maintenance therapy. The median vedolizumab trough level at week 30 was 16.0 μg/ml (interquartile range, 7.3–24.4). The vedolizumab trough level of the patients with clinical remission (partial Mayo score ≤1) was significantly higher than that of clinically active patients (16.7 μg/ml vs 6.8). The cut-off value of vedolizumab level predicting clinical remission at week 30 was 7.34 μg/ml. The median AVA level of patients under vedolizumab maintenance therapy was similar to that of healthy controls (n = 20) (0.032 μg/ml-c vs 0.022). One of 37 patients (2.7%) was judged to be AVA positive. There was no significant difference in serum AVA and vedolizumab trough levels between biologics-naïve (n = 19) and biologics-switched (prior anti-TNFα-exposed) patients (n = 18). In conclusion, the simple drug-tolerant assay developed in our laboratory demonstrated low immuno­genicity of vedolizumab. Prior use of anti-TNFα drugs did not affect the immunogenicity of vedolizumab.

Treatment of inflammatory bowel diseases: focusing on biologic agents and new therapies

Background: The treatment of inflammatory bowel diseases has evolved with the development of anti-tumor necrosis factor agents. Despite the long-term effectiveness, many patients experience primary non-response, secondary loss of response, or intolerance. Therefore, the development of new drugs that act on different inflammatory pathways has become necessary. This review focuses on biologic agents and new therapies for the treatment of inflammatory bowel diseases.Current Concepts: Vedolizumab, a gut-selective agent that targets α4β7 integrin is effective in both ulcerative colitis and Crohn’s disease. Ustekinumab is a monoclonal antibody that binds to p40 subunit of interleukin-12/interleukin-23. Ustekinumab is available for the treatment of Crohn’s disease and ulcerative colitis. Tofacitinib is the first Janus kinase inhibitor approved for the treatment of ulcerative colitis. The advantage of tofacitinib is an oral prescription medicine and has rapid action.Discussion and Conclusion: Since vedolizumab, ustekinumab and tofacitinib are effective agents for the treatment of inflammatory bowel diseases, positioning of old and new biologic agents and small molecules should be determined. The safety and efficacy of novel and emerging drugs needs to be evaluated in patients with inflammatory bowel disease.

Pathogenic T Cells in Celiac Disease Change Phenotype on Gluten Challenge: Implications for T-Cell-Directed Therapies.

Gluten‐specific CD4+ T cells being drivers of celiac disease (CeD) are obvious targets for immunotherapy. Little is known about how cell markers harnessed for T‐cell‐directed therapy can change with time and upon activation in CeD and other autoimmune conditions. In‐depth characterization of gluten‐specific CD4+ T cells and CeD‐associated (CD38+ and CD103+) CD8+ and γδ + T cells in blood of treated CeD patients undergoing a 3 day gluten challenge is reported. The phenotypic profile of gluten‐specific cells changes profoundly with gluten exposure and the cells adopt the profile of gluten‐specific cells in untreated disease (CD147+, CD70+, programmed cell death protein 1 (PD‐1)+, inducible T‐cell costimulator (ICOS)+, CD28+, CD95+, CD38+, and CD161+), yet with some markers being unique for day 6 cells (C‐X‐C chemokine receptor type 6 (CXCR6), CD132, and CD147) and with integrin α4β7, C‐C motif chemokine receptor 9 (CCR9), and CXCR3 being expressed stably at baseline and day 6. Among gluten‐specific CD4+ T cells, 52% are CXCR5+ at baseline, perhaps indicative of germinal‐center reactions, while on day 6 all are CXCR5−. Strikingly, the phenotypic profile of gluten‐specific CD4+ T cells on day 6 largely overlaps with that of CeD‐associated (CD38+ and CD103+) CD8+ and γδ + T cells. The antigen‐induced shift in phenotype of CD4+ T cells being shared with other disease‐associated T cells is relevant for development of T‐cell‐directed therapies.

Efficacy and Safety of Vedolizumab in Management of Moderate to Severe Ulcerative Colitis: A Systematic Review.

Ulcerative colitis (UC) is an inflammatory bowel disease and causes inflammation and ulcer of the colon. Vedolizumab is a newer biological agent with an inhibitory effect on α4β7 integrin approved for moderate to severe UC patients. Our study reviewed the clinical response, clinical remission, and mucosal healing of vedolizumab in moderate to severe UC management. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a literature search in PubMed, Google Scholar, and Science Direct, and nine studies were included in the systematic review. At week six, vedolizumab showed a significant clinical response. At week 52, vedolizumab showed significant mucosal healing and clinical remission. The most commonly associated adverse effects are nasopharyngitis, oropharyngeal infection, and gastrointestinal infection. However, additional clinical trials and observational studies with longer follow-ups are required to study the efficacy and safety of the drug.

PTG-100, an Oral α4β7 Antagonist Peptide: Preclinical Development and Phase 1 and 2a Studies in Ulcerative Colitis

Oral therapies targeting the integrin α4β7 may offer unique advantages for the treatment of inflammatory bowel disease. We characterized the oral α4β7 antagonist peptide PTG-100 in preclinical models and established safety, pharmacokinetic/pharmacodynamic relationships, and efficacy in a phase 2a trial in patients with ulcerative colitis (UC). Invitro studies measured binding properties of PTG-100. Mouse studies measured biomarkers and drug concentrations in blood and tissues. The phase 1 study involved healthy volunteers. In phase 2a, patients with moderate to severe active UC were randomized to receive PTG-100 (150, 300, or 900 mg) or placebo once daily for 12-weeks. PTG-100 potently and selectively blocks α4β7. Oral dosing of PTG-100 in mice showed high levels of target engagement and exposure in gut-associated lymphoid tissues. In healthy volunteers, PTG-100 showed dose-dependent increases in plasma exposure and blood target engagement. Although this phase 2a study initially did not meet the primary endpoint, a blinded reread of the endoscopy videos by a third party indicated clinical efficacy in conjunction with histologic remission at doses correlating with less than 100% receptor occupancy in peripheral blood. PTG-100 showed local gastrointestinal tissue target engagement and inhibition of memory T-cell trafficking in mice. It was safe and well tolerated in phase 1 and 2 studies. Phase 2a data are consistent with biological and clinical response and showed a dose response reflecting similar activities in preclinical models and healthy individuals. These data suggest that local gut activity of an oral α4β7 integrin antagonist, distinct from full target engagement in blood, are important for efficacy and the treatment of UC. (ClinicalTrials.gov, Number NCT02895100; EudraCT, Number 2016-003452-75).

Clinical response of vedolizumab at week 6 predicted endoscopic remission at week 24 in ulcerative colitis.

Background and AimVedolizumab is a humanized monoclonal antibody that selectively inhibits the migration of gut‐homing memory T cells into the intestinal submucosa by antagonizing the interaction of α4β7 integrin with MAdCAM‐1. Vedolizumab is employed for ulcerative colitis with moderate to severe activity; however, predictors of its clinical efficacy have not been established in real‐world clinical practice. We investigated the clinical characteristics predicting vedolizumab efficacy.MethodsThis was a single‐center, retrospective, observational study that enrolled patients with ulcerative colitis at Kyorin University Hospital. Fifty‐two consecutive patients who started vedolizumab induction therapy and were tracked for minimum 14 weeks between August 2018 and February 2021 were included. Clinical and endoscopic disease activities were scored at baseline and at weeks 2, 6, and 14 with the Lichtiger index and at baseline and week 24 with the Mayo endoscopic subscore, respectively. Clinical remission, clinical response, and endoscopic remission were defined as Lichtiger index of ≤3, Lichtiger index of ≤10 with a reduction of minimum 3 points from baseline, and Mayo endoscopic subscore of ≤1, respectively.ResultsIn these cases, clinical response/remission rates at weeks 2, 6, and 14 were 26.9%/15.3%, 50.0%/46.3%, and 57.6%/50.0%, respectively. The endoscopic remission rate at week 24 was 60%. The clinical response at week 6 was significantly associated with endoscopic remission at week 24 after starting vedolizumab.ConclusionsIn vedolizumab treatment for ulcerative colitis, the clinical response at week 6 can be a predictor for endoscopic remission at week 24.