Burden of Bowel Urgency in Patients With Ulcerative Colitis and Crohn's Disease: A Real-World Global Study.

Background: Bowel urgency is a highly disruptive and bothersome symptom experienced by patients with inflammatory bowel diseases (IBD), (ulcerative colitis [UC], and Crohn's disease [CD]). However, the burden of bowel urgency among patients with varying experiences in targeted treatment has not been consistently assessed. This real-world study explored the clinical and health-related quality of life burden of bowel urgency among patients with IBD with differing treatment experiences. Methods: This cross-sectional survey included gastroenterologists and their patients with IBD across France, Germany, Italy, Spain, the United Kingdom, and the United States treated for over 3 months. Physicians provided patient demographics, clinical characteristics, and treatment history. Patients reported their health-related quality of life and work productivity. Patients with UC and CD were analyzed separately and stratified into 3 groups: Targeted therapy naïve, those receiving their first-line targeted therapy, and targeted therapy experienced. Results: This study found that 17%-26% of UC and 13%-17% of CD patients experienced persistent bowel urgency, irrespective of receiving conventional or targeted therapy. Moreover, patients with bowel urgency experienced an increased clinical and health-related quality of life burden compared to patients without bowel urgency, which physicians most commonly regarded as one of the most difficult symptoms to treat, with the burden remaining substantial irrespective of their treatment experience. Conclusions: Despite several current treatment options, new therapeutic strategies are necessary to provide relief from bowel urgency, one of the most challenging symptoms for people living with IBD.

Integrin αVß6 - autoantigen and driver of epithelial remodeling in colon and bile ducts in primary sclerosing cholangitis and inflammatory bowel disease.

OBJECTIVE: Recently, autoantibodies directed against the epithelial adhesion protein integrin αVß6 have been identified which strongly associate with ulcerative colitis (UC). We aimed to elucidate whether anti-integrin αVß6 (anti- αVß6) is present in primary sclerosing cholangitis (PSC), its associated inflammatory bowel disease or other cholestatic liver diseases and their persistence after proctocolectomy. DESIGN: We detected anti- αVß6 by an enzyme-linked immunosorbent assay in sera collected at two German tertiary centers, including healthy controls (N=62), UC (N=36), Crohn's disease (CD, N=65), PSC-IBD (78 samples from N=41 patients), PSC without IBD (PSC, 41 samples from N=18 patients), primary biliary cholangitis (PBC, N=24), autoimmune hepatitis (AIH, N=32), secondary sclerosing cholangitis (SSC, N=12) and metabolic dysfunction-associated steatotic liver disease (MASLD, N=24). Additionally, sera after proctocolectomy were studied (44 samples / N= 10 patients). Immunofluorescent analyses were performed in tissue samples from liver, large bile duct from surgical resections and colon of PSC patients. RESULTS: Anti- αVß6 occurred in 91% of UC, 17% of CD, 73% of PSC-IBD, 39% of PSC, 4% of PBC, 14% of AIH, and 0% of healthy controls, SSC or MASLD. Integrin αVß6 is selectively expressed in disease-associated epithelia of both bile duct and colon. Anti- αVß6 levels correlate moderately with intestinal disease activity in PSC-IBD, but only weakly with biliary disease. CONCLUSION: Anti- αVß6 frequently occur in patients suffering from PSC, especially in PSC-IBD. Anti- αVß6 levels positively correlate to IBD activity in PSC-IBD, but may also occur in the absence of clinically manifest IBD in PSC.

Risankizumab for Ulcerative Colitis: Two Randomized Clinical Trials.

Importance: The clinical effects of risankizumab (a monoclonal antibody that selectively targets the p19 subunit of IL-23) for the treatment of ulcerative colitis are unknown. Objective: To evaluate the efficacy and safety of risankizumab when administered as an induction and a maintenance therapy for patients with ulcerative colitis. Design, Setting, and Participants: Two phase 3 randomized clinical trials were conducted. The induction trial was conducted at 261 clinical centers (in 41 countries) and enrolled 977 patients from November 5, 2020, to August 4, 2022 (final follow-up on May 16, 2023). The maintenance trial was conducted at 238 clinical centers (in 37 countries) and enrolled 754 patients from August 28, 2018, to March 30, 2022 (final follow-up on April 11, 2023). Eligible patients had moderately to severely active ulcerative colitis; a history of intolerance or inadequate response to 1 or more conventional therapies, advanced therapies, or both types of therapies; and no prior exposure to risankizumab. Interventions: For the induction trial, patients were randomized 2:1 to receive 1200 mg of risankizumab or placebo administered intravenously at weeks 0, 4, and 8. For the maintenance trial, patients with a clinical response (determined using the adapted Mayo score) after intravenous treatment with risankizumab were randomized 1:1:1 to receive subcutaneous treatment with 180 mg or 360 mg of risankizumab or placebo (no longer receiving risankizumab) every 8 weeks for 52 weeks. Main Outcomes and Measures: The primary outcome was clinical remission (stool frequency score ≤1 and not greater than baseline, rectal bleeding score of 0, and endoscopic subscore ≤1 without friability) at week 12 for the induction trial and at week 52 for the maintenance trial. Results: Among the 975 patients analyzed in the induction trial (aged 42.1 [SD, 13.8] years; 586/973 [60.1%] were male; and 677 [69.6%] were White), the clinical remission rates at week 12 were 132/650 (20.3%) for 1200 mg of risankizumab and 20/325 (6.2%) for placebo (adjusted between-group difference, 14.0% [95% CI, 10.0%-18.0%], P < .001). Among the 548 patients analyzed in the maintenance trial (aged 40.9 [SD, 14.0] years; 313 [57.1%] were male; and 407 [74.3%] were White), the clinical remission rates at week 52 were 72/179 (40.2%) for 180 mg of risankizumab, 70/186 (37.6%) for 360 mg of risankizumab, and 46/183 (25.1%) for placebo (adjusted between-group difference for 180 mg of risankizumab vs placebo, 16.3% [97.5% CI, 6.1%-26.6%], P < .001; adjusted between-group difference for 360 mg of risankizumab vs placebo, 14.2% [97.5% CI, 4.0%-24.5%], P = .002). No new safety risks were detected in the treatment groups. Conclusion and Relevance: Compared with placebo, risankizumab improved clinical remission rates in an induction trial and in a maintenance trial for patients with moderately to severely active ulcerative colitis. Further study is needed to identify benefits beyond the 52-week follow-up. Trial Registration: ClinicalTrials.gov Identifiers: NCT03398148 and NCT03398135.

Gut Pathobiont-Derived Outer Membrane Vesicles Drive Liver Inflammation and Fibrosis in Primary Sclerosing Cholangitis-Associated Inflammatory Bowel Disease.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC), often associated with inflammatory bowel disease (IBD), presents a multifactorial etiology involving genetic, immunologic, and environmental factors. Gut dysbiosis and bacterial translocation have been implicated in PSC-IBD, yet the precise mechanisms underlying their pathogenesis remain elusive. Here, we describe the role of gut pathobionts in promoting liver inflammation and fibrosis due to the release of bacterial outer membrane vesicles (OMVs). METHODS: Preclinical mouse models in addition to ductal organoids were used to acquire mechanistic data. A proof-of-concept study including serum and liver biopsies of a patient cohort of PSC (n = 22), PSC-IBD (n = 45), and control individuals (n = 27) was performed to detect OMVs in the systemic circulation and liver. RESULTS: In both preclinical model systems and in patients with PSC-IBD, the translocation of OMVs to the liver correlated with enhanced bacterial sensing and accumulation of the NLRP3 inflammasome. Using ductal organoids, we were able to precisely attribute the pro-inflammatory and pro-fibrogenic properties of OMVs to signaling pathways dependent on Toll-like receptor 4 and NLRP3-gasdermin-D. The immunostimulatory potential of OMVs could be confirmed in macrophages and hepatic stellate cells. Furthermore, when we administered gut pathobiont-derived OMVs to Mdr2-/- mice, we observed a significant enhancement in liver inflammation and fibrosis. In a translational approach, we substantiated the presence of OMVs in the systemic circulation and hepatic regions of severe fibrosis using a PSC-IBD patient cohort. CONCLUSIONS: This study demonstrates the contribution of gut pathobionts in releasing OMVs that traverse the mucosal barrier and, thus, promote liver inflammation and fibrosis in PSC-IBD. OMVs might represent a critical new environmental factor that interacts with other disease factors to cause inflammation and thus define potential new targets for fibrosis therapy.

Methylation Analysis of Colitis-Associated Colorectal Carcinomas.

BACKGROUND: Ulcerative colitis is a well-known inflammatory bowel disease. Patients have an increased risk of developing colitis associated carcinoma (CAC). It is important for patient management to be able to distinguish between ulcerative colitis associated carcinoma and sporadic carcinoma (sCRC). However, this distinction is frequently very challenging. It is not readily possible to differentiate this histologically. However, the diagnosis is crucial for the patient's further treatment and follow-up. An attempt was therefore made to develop a diagnostic regime that would enable a reliable distinction between sCRC and CAC. METHODS: We screened 96 patients analyzing more than 850,000 methylation hotspots, to detect distinct epigenetic patterns between both types of carcinomas. Patients with sporadic carcinoma and colitis-associated carcinoma as well as patients with normal colon and patients with confirmed ulcerative colitis without neoplasia were used for the analysis. By extensively filtering the results, methylation sites relevant to distinguish between CAC and sCRC were identified. RESULTS: After the results were filtered, three methylation sites relevant to distinguish between CAC and sCRC were identified. For this purpose, methylation limit values were defined, which favor the samples as CAC or sCRC up to a certain methylation value of the methylation sites. The combination of three methylation sites allows a correct assignment to CAC or sCRC in 94.5% of the cases. CONCLUSION: The results show that these three methylation sites are promising markers in the diagnosis of CAC vs sCRC. Nevertheless, the diagnosis should always be made in conjunction with histomorphological analyses.

Risankizumab versus Ustekinumab for Moderate-to-Severe Crohn's Disease.

BACKGROUND: The efficacy and safety of risankizumab as compared with ustekinumab in patients with Crohn's disease are unknown. METHODS: In this phase 3b, multicenter, open-label, randomized, controlled trial with blinded assessment of end points, patients with moderate-to-severe Crohn's disease who had had an inadequate response to anti-tumor necrosis factor (TNF) therapy or unacceptable side effects with such therapy were randomly assigned to receive risankizumab or ustekinumab at standard doses for 48 weeks. The two primary end points, which were tested sequentially, were clinical remission at week 24 (defined as a Crohn's Disease Activity Index score of <150 [range, 0 to 600, with higher scores indicating more severe disease activity]), which was analyzed in the first 50% of patients to complete the week 24 visit, with a noninferiority margin of 10 percentage points; and endoscopic remission at week 48 (defined as a score of ≤4, a decrease of ≥2 points from baseline, and no subscore >1 in any individual variable on the Simple Endoscopic Score for Crohn's Disease [range, 0 to 56, with higher scores indicating more severe disease]), which was analyzed for superiority in 100% of the patients. Safety was assessed in all patients who received at least one dose of risankizumab or ustekinumab. RESULTS: In the full intention-to-treat population for the efficacy analysis, 230 of 255 patients (90.2%) who received risankizumab and 193 of 265 patients (72.8%) who received ustekinumab completed all the assigned treatments. Both primary end points were met; risankizumab was noninferior to ustekinumab with respect to clinical remission at week 24 (58.6% vs. 39.5%; adjusted difference, 18.4 percentage points; 95% confidence interval [CI], 6.6 to 30.3) and superior to ustekinumab with respect to endoscopic remission at week 48 (31.8% vs. 16.2%; adjusted difference, 15.6 percentage points; 95% CI, 8.4 to 22.9; P<0.001). The incidence of adverse events appeared to be similar in the two groups. CONCLUSIONS: In this head-to-head clinical trial of risankizumab and ustekinumab involving patients with moderate-to-severe Crohn's disease who had had unacceptable side effects with anti-TNF therapy or an inadequate response to such therapy, risankizumab was noninferior to ustekinumab with respect to clinical remission at week 24 and superior with respect to endoscopic remission at week 48. (Funded by AbbVie; ClinicalTrials.gov number, NCT04524611.).

ECCO Guidelines on Therapeutics in Crohn's Disease: Surgical Treatment.

This article is the second in a series of two publications on the European Crohn's and Colitis Organisation [ECCO] evidence-based consensus on the management of Crohn's disease. The first article covers medical management; the present article addresses surgical management, including preoperative aspects and drug management before surgery. It also provides technical advice for a variety of common clinical situations. Both articles together represent the evidence-based recommendations of the ECCO for Crohn's disease and an update of prior ECCO guidelines.

Add-on multiple submucosal injections of the RNA oligonucleotide GUT-1 to anti-TNF antibody treatment in patients with moderate-to-severe ulcerative colitis: an open-label, proof-of concept study.

BACKGROUND: Carbohydrate sulfotransferase 15 (CHST15) is an enzyme biosynthesizing matrix glycosaminoglycan that modulates tissue remodeling. We evaluated the efficacy of add-on submucosal injections of GUT-1, the RNA oligonucleotide inhibitor of CHST15, to ongoing anti-tumor necrosis factor (TNF) antibody treatment in patients with moderate-to-severe ulcerative colitis (UC). METHODS: This was an open-label study of 250 nM of GUT-1 by endoscopic submucosal injections at weeks 0, 2, 4 in five UC patients who lost response during maintenance treatment to anti-TNF antibodies. The primary endpoint was the rate of endoscopic improvement at week 6 and secondary endpoints included the rates of clinical remission by modified Mayo Score (mMS). Patients received follow-up observation with continuous maintenance treatment by the same anti-TNF antibody till the time of clinical recurrence or for overall 52 weeks. RESULTS: At week 6, rates of endoscopic improvement and clinical remission were 80% (n = 4/5) and 60% (n = 3/5), respectively. The mean Endoscopy Subscore was reduced from 2.4 (95%CI: 1.7 to 3.1) at baseline, to 1.0 (95%CI: 0.1 to 1.9) at week 6. The mean mMS was reduced from 7.8 (95%CI: 6.2 to 9.4) to 1.3 (95%CI: 2.9 to 4.3). GUT-1 was well tolerated. Three patients did not show clinical recurrence for 52 weeks. All three corticosteroid-dependent patients showed no corticosteroid exposure for at least 24 weeks after achieving clinical remission. Multiple dosing was also well tolerated. CONCLUSIONS: Add-on multiple injections of GUT-1 to ongoing anti-TNF antibody was able to induce rapid and durable clinical responses in UC patients who lost response to anti-TNF therapy. TRIAL REGISTRATION: Clinical trial Registration Number (Japan): UMIN000020900.

Upadacitinib Achieves Clinical and Endoscopic Outcomes in Crohn's Disease Regardless of Prior Biologic Exposure.

BACKGROUND & AIMS: Upadacitinib, an oral Janus kinase inhibitor, achieved significantly higher rates of clinical remission and endoscopic response vs placebo during induction (U-EXCEL [NCT03345849], U-EXCEED [NCT03345836]) and maintenance (U-ENDURE [NCT03345823]) treatment in patients with moderate-to-severe Crohn's disease. Prior biologic failure is often associated with reduced responses to subsequent therapies. This post hoc analysis assessed upadacitinib efficacy by prior biologic failure status. METHODS: Patients were randomized to placebo or upadacitinib 45 mg (UPA45) for 12 weeks (induction). UPA45 clinical responders were enrolled in U-ENDURE and rerandomized to placebo, upadacitinib 15 mg, or upadacitinib 30 mg (UPA30) for 52 weeks. Assessments were by prior biologic failure. RESULTS: Of 1021 patients, 733 (71.8%) had prior biologic failure. Across outcomes and subgroups, upadacitinib-treated patients achieved higher rates vs placebo. During induction, upadacitinib had higher rates vs placebo for clinical remission based on stool frequency/abdominal pain score (without failure: 54.0% vs 28.3%; with failure: 42.2% vs 14.1%) and endoscopic response (without failure: 52.0% vs 16.2%; with failure: 35.7% vs 5.3%). In maintenance, the greatest treatment effect (upadacitinib vs placebo) was among patients with prior biologic failure treated with UPA30 (clinical remission without failure: 58.5% vs 32.7%; with failure: 42.5% vs 8.7%; endoscopic response without failure: 43.9% vs 17.9%; with failure: 38.9% vs 4.0%). Patients without vs with prior biologic failure had fewer adverse events. CONCLUSIONS: Upadacitinib led to higher absolutes rates of clinical and endoscopic outcomes in patients without vs with prior biologic failure. Patients treated with upadacitinib achieved greater rates of clinical and endoscopic improvements vs placebo, regardless of prior biologic exposure. CLINICALTRIALS: gov: NCT03345849, NCT03345836, NCT03345823.

Upadacitinib Reduces Crohn's Disease Symptoms Within the First Week of Induction Therapy.

BACKGROUND & AIMS: Upadacitinib (UPA), an oral Janus kinase inhibitor, is approved to treat moderately to severely active Crohn's disease (CD). Because symptomatic response is an important initial treatment goal for patients, we evaluated the rapidity of symptomatic improvement in patients with CD receiving UPA 45 mg once daily (UPA45) induction therapy. METHODS: This post hoc analysis included pooled data from 2 phase 3, multicenter, double-blind, 12-week induction trials (U-EXCEL and U-EXCEED) and 1 maintenance trial (U-ENDURE). Daily diary data for the first 15 days of UPA45 or placebo (PBO) treatment were used to analyze improvement in very soft/liquid stool frequency (SF) and abdominal pain score (APS). Clinical outcomes were evaluated at every study visit. RESULTS: Overall, 1021 patients (n = 674 UPA45; n = 347 PBO) were analyzed. UPA45 demonstrated greater efficacy vs PBO for SF <3 and APS ≤1, providing rapid relief by day 5 or 6, regardless of prior biologic exposure. Mean changes in SF and APS were greater with UPA45 beginning at week 2 (-2.0 and -0.5, respectively; P < .001) and were maintained through week 12 (-3.0 and -1.0, respectively; P < .001) vs PBO. The first achievement of daily SF/APS clinical remission occurred earlier with UPA45 (median, 13 d) vs PBO (median, 32 d), and patients treated with UPA45 showed improved rates of SF/APS clinical remission (21.1% UPA45 vs 8.9% PBO) and clinical response (58.8% UPA45 vs 37.9% PBO) starting at week 2 (both P ≤ .01). CONCLUSIONS: UPA45 provided rapid relief of clinical symptoms within the first week of treatment in patients with CD. CLINICALTRIALS: gov numbers: NCT03345849, NCT03345836, and NCT03345823.

Comparative efficacy and safety of subcutaneous infliximab and vedolizumab in patients with Crohn's disease and ulcerative colitis included in randomised controlled trials.

BACKGROUND: While indirect comparison of infliximab (IFX) and vedolizumab (VDZ) in adults with Crohn's disease (CD) or ulcerative colitis (UC) shows that IFX has better effectiveness during induction, and comparable efficacy during maintenance treatment, comparative data specific to subcutaneous (SC) IFX (i.e., CT-P13 SC) versus VDZ are limited. AIM: Pooled analysis of randomised studies to compare efficacy and safety with IFX SC and VDZ in moderate-to-severe inflammatory bowel disease. METHODS: Parallel-group, randomised studies evaluating IFX SC and VDZ in patients with moderate-to-severe CD or UC were identified. Eligible studies reported ≥ 1 prespecified outcome of interest at Week 6 (reflecting treatment during the induction phase) and/or at 1 year (Weeks 50-54; reflecting treatment during the maintenance phase). Prespecified efficacy and safety outcomes considered in this pooled analysis included the proportions of patients achieving disease-specific clinical responses, clinical remission, or discontinuing due to lack of efficacy, and the proportions of patients experiencing adverse events (AEs), serious AEs, infections, serious infections, or discontinuing due to AEs. Data from multiple studies or study arms were extracted and pooled using a random-effect model; comparative analyses were performed separately for patients with CD and UC. RESULTS: We identified three eligible CD trials and four eligible UC trials that assigned over 1200 participants per disease cohort to either IFX SC or VDZ. In patients with CD, intravenous induction therapy with IFX demonstrated better efficacy (non-overlapping 95% confidence intervals [CIs]) compared with VDZ; during the maintenance phase, IFX SC showed numerically better efficacy (overlapping 95% CIs) than VDZ. A lower proportion of IFX SC-treated patients discontinued therapy due to lack of efficacy over 1 year. In patients with UC, efficacy profiles were similar with IFX SC and VDZ during the induction and maintenance phases, and a lower proportion of IFX SC-treated patients discontinued therapy due to lack of efficacy over 1 year. In both cohorts, safety profiles for IFX SC and VDZ were generally comparable during 1 year. CONCLUSION: IFX SC demonstrated better efficacy than VDZ in patients with CD, and similar efficacy to VDZ in patients with UC; 1-year safety was comparable with IFX SC and VDZ.

Clinical Pharmacist Counselling Improves Long-term Medication Safety and Patient-reported Outcomes in Anti-TNF-treated Patients With Inflammatory Bowel Diseases: The Prospective, Randomized AdPhaNCED Trial.

BACKGROUND: Antitumor necrosis factor (anti-TNF) antibody treatment has led to marked improvements in the management of patients with inflammatory bowel diseases (IBDs). Nevertheless, anti-TNF therapy is associated with potential adverse drug reactions (ADRs). Our prospective, randomized trial investigated the effect of intensified clinical pharmacist counselling in a multidisciplinary team on medication safety in anti-TNF-treated IBD patients. METHODS: Patients with IBD with ongoing anti-TNF treatment were enrolled in our tertiary center AdPhaNCED trial and randomized to either receive conventional standard of care (control group) or additional clinical pharmacist counselling (intervention group) over 12 months. The primary end point consisted of the number and severity of ADRs associated with anti-TNF therapy. Secondary end points included patient satisfaction with medication information and medication safety. RESULTS: One hundred twenty-seven IBD patients were included in this study. Anti-TNF-related ADRs were significantly lower in the intervention compared with the control group (0.20 vs 0.32 [mean] ADR/patient/month, P = .006) after 12 months. The risk of more severe ADRs (Common Terminology Criteria for Adverse Events [CTCAE] grade ≥2) was significantly higher in the control compared with the intervention group (hazard ratio, 0.34; P = .001). The probability of ADR resolution (hazard ratio, 2.02; P < .001) and patient satisfaction with medication information (14.82 vs 11.60; P < .001) were significantly higher in the intervention group compared with the control group. CONCLUSIONS: Our study results demonstrate that intensified pharmacist counselling significantly reduces the occurrence and severity of therapy-related ADRs and improves patient satisfaction. Clinical pharmacists should therefore be part of a holistic approach to IBD care delivered by a multidisciplinary team.

The prospective, randomized AdPhaNCED trial demonstrated that anti-TNF-treated IBD patients had diminished and less severe drug-related adverse reactions and higher patient satisfaction when they received intensified pharmacist counselling in comparison with conventional standard of care over 12 months.

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.

Etrolizumab-s fails to control E-Cadherin-dependent co-stimulation of highly activated cytotoxic T cells.

Despite promising preclinical and earlier clinical data, a recent phase III trial on the anti-ß7 integrin antibody etrolizumab in Crohn's disease (CD) did not reach its primary endpoint. The mechanisms leading to this outcome are not well understood. Here we characterize the ß7+ T cell compartment from patients with CD in comparison to cells from individuals without inflammatory bowel disease. By flow cytometric, transcriptomic and functional profiling of circulating T cells, we find that triple-integrin-expressing (α4+ß7+ß1hi) T cells have the potential to home to the gut despite α4ß7 blockade and have a specific cytotoxic signature. A subset of triple-integrin-expressing cells readily acquires αE expression and could be co-stimulated via E-Cadherin-αEß7 interactions in vitro. Etrolizumab-s fails to block such αEß7 signalling at high levels of T cell stimulation. Consistently, in CD patients treated with etrolizumab, T cell activation correlates with cytotoxic signatures. Collectively, our findings might add one important piece to the puzzle to explain phase III trial results with etrolizumab, while they also highlight that αEß7 remains an interesting target for future therapeutic approaches in inflammatory bowel disease.

Blocking GPR15 Counteracts Integrin-dependent T Cell Gut Homing in Vivo.

BACKGROUND AND AIMS: The G protein coupled receptor GPR15 is expressed on and functionally important for T cells homing to the large intestine. However, the precise mechanisms by which GPR15 controls gut homing have been unclear. Thus, we aimed to elucidate these mechanisms as well as to explore the potential of targeting GPR15 for interfering with T cell recruitment to the colon in inflammatory bowel disease [IBD]. METHODS: We used dynamic adhesion and transmigration assays, as well as a humanised in vivo model of intestinal cell trafficking, to study GPR15-dependent effects on gut homing. Moreover, we analysed GPR15 and integrin expression in patients with and without IBD, cross-sectionally and longitudinally. RESULTS: GPR15 controlled T cell adhesion to MAdCAM-1 and VCAM-1 upstream of α4ß7 and α4ß1 integrin, respectively. Consistently, high co-expression of these integrins with GPR15 was found on T cells from patients with IBD, and GPR15 also promoted T cell recruitment to the colon in humanised mice. Anti-GPR15 antibodies effectively blocked T cell gut homing in vitro and in vivo. In vitro data, as well as observations in a cohort of patients treated with vedolizumab, suggest that this might be more effective than inhibiting α4ß7. CONCLUSIONS: GPR15 seems to have a broad, but organ-selective, impact on T cell trafficking and is therefore a promising target for future therapy of IBD. Further studies are needed.