Proactive Therapeutic Drug Monitoring Is Associated With Increased Drug Persistence in Patients With Inflammatory Bowel Disease Treated With Intravenous Vedolizumab.

BACKGROUND: There are limited data regarding therapeutic drug monitoring (TDM) of non-anti-tumor necrosis factor therapy in inflammatory bowel disease (IBD). This study aimed to evaluate the efficacy of proactive TDM in IBD patients treated with intravenous (iv) vedolizumab (VDZ). METHODS: This single-center retrospective cohort study included consecutive IBD patients treated with maintenance iv VDZ therapy undergoing TDM from November 2016 to March 2023. Patients were followed through June 2023 and were divided in to 2 groups: those who had at least 1 proactive TDM vs those who underwent only reactive TDM. A survival analysis was performed to evaluate drug persistence, defined as no need for drug discontinuation due to loss of response, serious adverse event, or an IBD-related surgery. RESULTS: The study population consisted of 94 patients (proactive TDM, n = 72) with IBD (ulcerative colitis, n = 53). Patients undergoing at least 1 proactive TDM compared with patients having only reactive TDM demonstrated a higher cumulative probability of drug persistence (Log-rank P < .001). In multivariable Cox proportional hazard regression analysis, at least 1 proactive TDM was the only factor associated with drug persistence (hazard ratio, 14.3; 95% confidence interval [CI], 3.8-50; P < .001). A ROC analysis identified a VDZ concentration of 12.5 µg/mL as the optimal drug concentration threshold associated with drug persistence (area under the ROC curve: 0.691; 95% CI, 0.517-0.865; P = .049). CONCLUSION: In this single-center retrospective study reflecting real-life clinical practice, proactive TDM was associated with increased drug persistence in patients with IBD treated with iv VDZ.

There are limited data regarding therapeutic drug monitoring (TDM) of non-anti-tumor necrosis factor therapy in inflammatory bowel disease (IBD). We found that proactive TDM was associated with drug persistence in patients with IBD treated with vedolizumab. Moreover, a vedolizumab concentration of 12.5 µg/mL was identified as the optimal drug concentration threshold associated with drug persistence.

Reduction of product composition variability using pooled microbiome ecosystem therapy and consequence in two infectious murine models.

Growing evidence demonstrates the key role of the gut microbiota in human health and disease. The recent success of microbiotherapy products to treat recurrent Clostridioides difficile infection has shed light on its potential in conditions associated with gut dysbiosis, such as acute graft-versus-host disease, intestinal bowel diseases, neurodegenerative diseases, or even cancer. However, the difficulty in defining a "good" donor as well as the intrinsic variability of donor-derived products' taxonomic composition limits the translatability and reproducibility of these studies. Thus, the pooling of donors' feces has been proposed to homogenize product composition and achieve higher taxonomic richness and diversity. In this study, we compared the metagenomic profile of pooled products to corresponding single donor-derived products. We demonstrated that pooled products are more homogeneous, diverse, and enriched in beneficial bacteria known to produce anti-inflammatory short chain fatty acids compared to single donor-derived products. We then evaluated pooled products' efficacy compared to corresponding single donor-derived products in Salmonella and C. difficile infectious mouse models. We were able to demonstrate that pooled products decreased pathogenicity by inducing a structural change in the intestinal microbiota composition. Single donor-derived product efficacy was variable, with some products failing to control disease progression. We further performed in vitro growth inhibition assays of two extremely drug-resistant bacteria, Enterococcus faecium vanA and Klebsiella pneumoniae oxa48, supporting the use of pooled microbiotherapies. Altogether, these results demonstrate that the heterogeneity of donor-derived products is corrected by pooled fecal microbiotherapies in several infectious preclinical models.IMPORTANCEGrowing evidence demonstrates the key role of the gut microbiota in human health and disease. Recent Food and Drug Administration approval of fecal microbiotherapy products to treat recurrent Clostridioides difficile infection has shed light on their potential to treat pathological conditions associated with gut dysbiosis. In this study, we combined metagenomic analysis with in vitro and in vivo studies to compare the efficacy of pooled microbiotherapy products to corresponding single donor-derived products. We demonstrate that pooled products are more homogeneous, diverse, and enriched in beneficial bacteria compared to single donor-derived products. We further reveal that pooled products decreased Salmonella and Clostridioides difficile pathogenicity in mice, while single donor-derived product efficacy was variable, with some products failing to control disease progression. Altogether, these findings support the development of pooled microbiotherapies to overcome donor-dependent treatment efficacy.

Effectiveness of golimumab intensification in ulcerative colitis: A multicentric prospective study.

INTRODUCTION: Loss of response to golimumab occurs in nearly 40% of patients with ulcerative colitis (UC). Unlike others anti-TNF, no study has reported a correlation between serum golimumab level and response to drug intensification. The objective of this study was to evaluate the effectiveness and safety of golimumab intensification and to identify the best threshold of serum golimumab before drug intensification predictive of response. PATIENTS AND METHODS: We included all consecutive patients with active UC with loss of response to golimumab in a prospective multicentric cohort study. Patients with loss of response at 50 mg q4 weeks (W) and 100 mg q4W underwent therapeutic intensification at 100 mg q4W and 100 mg q2W, respectively. Effectiveness and safety were assessed between Weeks 2 and 4 (visit 2) and between Weeks 4 and 8 (visit 3) after intensification. Serum level and anti-golimumab antibodies were evaluated at each medical visit (Lisa Tracker, Theradiag France). RESULTS: A total of 47 UC patients (Female, 50%; median age, 39 years (IQR, 27-52)) treated with golimumab for a median of 20.4 weeks (IQR, 10.7-38.3) were included. The median partial Mayo score was 6 (IQR, 5-7), and the median endoscopic Mayo score was 3 (IQR, 2-3). The median golimumab serum level before intensification was 2.23 µg/mL (IQR, 1.02-3.96) and only one patient (2.1%) had anti-drug antibodies. At Visit 2 (Week 2-4), 40% patients experienced clinical response, 10% clinical remission, 33% endoscopic response and 23% endoscopic remission. At Visit 3 (Week 4-8), 44% of patients had clinical response, 22% of patients had clinical remission, 45% of patients had endoscopic response, and 41% of patients had endoscopic remission. The median golimumab levels before intensification do not differ between responders and non-responders (2.13 µg/ml (0.76-2.76) and 3.37 µg/ml (IQR, 1.08-4.67), respectively; p = 0.14) assessed at Visit 3. Golimumab intensification to 100 mg q4W (vs q2W) (OR 1.98, 95% CI [1.06-3.70]; p = 0.032) was significantly associated with clinical remission at Visit 3. Serum drug level at baseline or the presence of antidrug antibodies were not associated with clinical or endoscopic remission/response. Two serious adverse events (one infection and one UC flare) were reported during the 24-week follow-up. CONCLUSION: In this prospective multicentric study, half of patients recaptured response following golimumab intensification in UC. Therapeutic drug monitoring did not predict response after optimisation of golimumab.

A Systematic Review on the Interest of Drug-tolerant Assay in the Monitoring of Inflammatory Bowel Disease.

Many patients with inflammatory bowel disease [IBD] are treated with anti-tumour necrosis factor [TNF] therapies, of which infliximab [IFX] is most commonly used. Loss of response [LOR] to anti-TNF therapy due to immunogenic failure accounts for 20% of subsequent medical intervention and is defined, using a drug-sensitive assay, as low or undetectable concentration of drug with high titres of anti-drug antibodies [ADAb]. We performed a systematic review to investigate the use of a drug-tolerant assay during both induction and maintenance, to monitor patients treated with anti-TNFs. After the search on PubMed, 90 publications were reviewed. Most ADAb detection methods are drug-sensitive, cannot detect ADAb in the presence of drug, and therefore cannot be used close to drug administration when the drug concentration is too high. To overcome this major limitation, several drug-tolerant techniques have been developed and will be discussed in this review. Using drug-tolerant assays, ADAb against IFX or adalimumab [ADM] can be detected during induction and predict primary non-response or LOR. Drug-sensitive assays do not allow detection of ADAb during the induction phase when IFX or ADM concentration is typically high.

Relationships of circulating CD4+ T cell subsets and cytokines with the risk of relapse in patients with Crohn's disease.

Background and aims: We aimed to analyze circulating CD4+ T cell subsets and cytokines during the course of Crohn's disease (CD). Methods and results: CD4+ T cell subsets, ultrasensitive C-reactive protein (usCRP), and various serum cytokines (IL-6, IL-8, IL-10, IL-13, IL-17A, IL-23, TNFα, IFNγ, and TGFß) were prospectively monitored every 3 months for 1 year, using multicolor flow cytometry and an ultrasensitive Erenna method in CD patients in remission at inclusion. Relapse occurred in 35 out of the 113 consecutive patients (31%). For patients in remission within 4 months prior to relapse and at the time of relapse, there was no significant difference in Th1, Th17, Treg, and double-positive CD4+ T cell subsets co-expressing either IFNγ and FOXP3, IL-17A and FOXP3, or IFNγ and IL-17A. On the contrary, in patients who remained in remission, the mean frequency and number of double-positive IL-17A+FOXP3+ CD4+ T cells and the level of usCRP were significantly higher (p ≤ 0.01) 1 to 4 months prior to relapse. At the time of relapse, only the IL-6 and usCRP levels were significantly higher (p ≤ 0.001) compared with those patients in remission. On multivariate analysis, a high number of double-positive IL-17A+FOXP3+ CD4+ T cells (≥1.4 cells/mm3) and elevated serum usCRP (≥3.44 mg/L) were two independent factors associated with risk of relapse. Conclusions: Detection of circulating double-positive FOXP3+IL-17A+ CD4+ T cell subsets supports that T cell plasticity may reflect the inflammatory context of Crohn's disease. Whether this subset contributes to the pathogenesis of CD relapse needs further studies.

Validation Study of a New Random-Access Chemiluminescence Immunoassay Analyzer i-TRACK10® to Monitor Infliximab and Adalimumab Serum trough Levels and Anti-Drug Antibodies.

Background. Monitoring of biological TNF inhibitors is a very important tool to guide clinical decisions using specialized algorithms, especially in gastroenterology. A new chemiluminescent instrument (i-TRACK10® from Theradiag) could replace ELISA techniques to calculate the dosage of drugs and anti-drug antibodies. In this bi-centric study, we explored the analytical performances of i-TRACK10® using manual or automated (DS2®) ELISA Lisa-Tracker® assays, and compared the results. Patients and methods. Intra- and inter-run performances were evaluated with i-TRACK10® in two different laboratories and for two different ranges of values for infliximab, adalimumab, and their respective antibodies. Patients' samples were used in the labs to compare the results obtained between the new instrument and either the manual Lisa-Tracker® or the automated DS2. Results. Intra- and inter-run performances were satisfactory, with values between 1.8% and 16.1% (for inter-run imprecision at low/medium values of infliximab). Results were generally comparable between assays. with the lowest value of correlation at 0.59 (anti-adalimumab dosage between i-TRACK10® and manual ELISA). Most often, values of drugs and anti-drug antibodies were higher with i-TRACK10® than with manual ELISA assay, and correlation values were better with automated ELISA. Agreements were globally acceptable, and the lowest coefficients of 0.7 was obtained for adalimumab values between i-TRACK10® and the two ELISA methods, and for anti-adalimumab values between i-TRACK10® and manual ELISA. The type of assay can potentially induce a change in the class of patients and lead to divergent therapeutic decisions. Conclusions. The new random-access instrument i-TRACK10® presents many advantages in a routine laboratory: rapidity, the possibility of standardization, usability, and expansion of the measurement range. Despite the relatively good agreement of results, it is preferable to use the same assay in longitudinal follow-up of a patient, because quantitative results were not completely equivalent especially for anti-drug antibodies.

Efficacy and Safety of Infliximab Retreatment in Crohn's Disease: A Multicentre, Prospective, Observational Cohort (REGAIN) Study from the GETAID.

INTRODUCTION: The objective of this study was to describe the efficacy and safety of infliximab (IFX) reintroduction in Crohn's disease (CD) after stopping for loss of response or intolerance. METHODS: We conducted a prospective multicenter observational cohort study including adult patients with clinically (CD Activity Index >150) and objectively active luminal CD in whom IFX was reintroduced after at least 6 months of discontinuation. The reasons for the initial discontinuation could be a secondary loss of response or IFX intolerance. The reintroduction schedule included 3 IFX infusions at weeks 0, 4, and 8, after a systematic premedication. The primary end point was the efficacy of IFX retreatment at week 26 defined by a CD Activity Index of <150 in the absence of IFX discontinuation or use of corticosteroids, surgery, or other biologic. RESULTS: At week 26, 24 patients (35%) among the 69 analyzed reached the primary end point. No significant difference was observed between rates of clinical remission at week 26 in patients with prior LOR (n = 48) and those with IFX intolerance (n = 21) (35% and 33%, P = 0.87, respectively). Thirty-two acute infusion reactions were recorded in 27 patients, leading to withdrawal of IFX in 20 patients. No pharmacokinetic characteristic at baseline but detection of positive anti-drug antibodies at week 4 was predictive of IFX failure or infusion reaction at week 26. DISCUSSION: In this first prospective cohort study, IFX retreatment was safe and effective in one-third of the patients with CD, regardless the reason of prior discontinuation. Early detection of anti-drug antibodies can predict subsequent IFX reintroduction failure and infusion reactions.

TAFRO syndrome: A severe manifestation of Sjogren's syndrome? A systematic review.

BACKGROUND: Sjögren's syndrome (SjS) is a systemic autoimmune disease characterized by lymphocytic infiltration of the salivary and lacrimal glands associated with sicca syndrome. TAFRO syndrome is a systemic inflammatory disease of unknown cause, characterized by Thrombocytopenia, Anasarca, Fever, Reticulin fibrosis, Renal dysfunction and Organomegaly, first reported in 2010 in Japanese patients. Despite their rarity, both conditions have been concurrently reported in several patients during the recent years, hence questioning the existence of shared or related features. METHODS: A systematic review of the literature regarding SjS associated with TAFRO syndrome (SjS-TAFRO) was performed. The 2019 updated Masaki diagnostic criteria were used for TAFRO syndrome and SjS was considered when the diagnosis was mentioned by the authors, necessarily with either anti-Sjogren's Syndrome A (SSA) ± anti-Sjogren's Syndrome B (SSB) antibodies and/or histological evidence of focal lymphocytic sialadenitis. RESULTS: Ten cases of SjS-TAFRO have been reported in the literature to date. Compared to SjS patients without TAFRO syndrome, these 10 SjS-TAFRO had a lower female predominance (2.3:1 vs 9:1 women to man ratio) and a higher frequency of anti-SSA antibodies (90% vs 70%). All fulfilled the three major Masaki criteria i.e., anasarca, thrombocytopenia, and systemic inflammation. Seven of them (70%) had megakaryocyte hyperplasia or reticulin fibrosis in the bone marrow. Lymph node biopsy was performed in 8 out of 10 cases (80%) and results were consistent with Castleman disease in 6 (75%). Eight of them had developed renal failure (80%) within six months. Nine of them (90%) had organomegaly, with hepatosplenomegaly in 8 cases and splenomegaly alone in 1. CONCLUSION: This review brings new insights regarding TAFRO syndrome and suggests it could be a severe manifestation of SjS. The identification of shared abnormal signaling pathways could help in the therapeutic management of both diseases, which face an unmet therapeutic need.

Alteration of microbiota antibody-mediated immune selection contributes to dysbiosis in inflammatory bowel diseases.

Human secretory immunoglobulins (SIg) A1 and SIgA2 guide mucosal responses toward tolerance or inflammation, notably through reverse-transcytosis, the apical-to-basal transport of IgA2 immune complexes via M cells of gut Peyer's patches. As such, the maintenance of a diverse gut microbiota requires broad affinity IgA and glycan-glycan interaction. Here, we asked whether IgA1 and IgA2-microbiota interactions might be involved in dysbiosis induction during inflammatory bowel diseases. Using stool HPLC-purified IgA, we show that reverse-transcytosis is abrogated in ulcerative colitis (UC) while it is extended to IgA1 in Crohn's disease (CD). 16S RNA sequencing of IgA-bound microbiota in CD and UC showed distinct IgA1- and IgA2-associated microbiota; the IgA1+ fraction of CD microbiota was notably enriched in beneficial commensals. These features were associated with increased IgA anti-glycan reactivity in CD and an opposite loss of reactivity in UC. Our results highlight previously unknown pathogenic properties of IgA in IBD that could support dysbiosis.

Subcutaneous injection of infliximab CT-P13 results in stable drug levels within 14-day treatment cycle in Crohn's disease.

The new subcutaneous (sc) formulation of the infliximab (IFX) biosimilar CT-P13 results in homogeneous serum trough concentrations of IFX at steady state. The present study aimed to investigate in Crohn's disease (CD) patients the intra-individual variations of IFX drug levels at multiple time-points during 2 consecutive cycles of maintenance therapy with CT-P13 sc. PATIENTS AND METHODS: CD patients in clinico-biological remission under maintenance therapy with intravenous (iv) IFX/CT-P13 were switched to CT-P13 sc 8 weeks (W) after the last infusion. They were treated with CT-P13 sc, 120 mg every 2 W. Assessments were performed from 8 W after starting CT-P13 sc and patients had to attend 6 visits on 2 consecutive cycles of treatment (cycles A and B). Visits were scheduled on days 4-6 (visit 1), days 7-9 (visit 2) and day 14 (visit 3) of each cycle, where days 1 and 14 were the days of sc injection of CT-P13. At each visit, peripheral blood was collected to measure serum IFX levels and anti-drug antibodies. RESULTS: Twenty patients underwent 120 evaluations. Large intra-individual variations of serum drug levels of IFX were observed. When pooling the 120 evaluations, the mean drug level was 11.3 ± 4.9 µg/ml, and the median drug level was 10.9 µg/ml (IQR 7.5-15.5). During each cycle, the median drug levels were similar between visits 1 and 2 as well as between visits 1 and 3 and between visits 2 and 3. In cycle A, median drug levels were 11.1 µg/ml (7.8-14.5), 12.0 µg/ml (7.2-16.1) and 11.0 µg/ml (7.5-15.1) at V1, V2 and V3, respectively. Similar results were obtained in cycle B, where median drug levels were 11.6 µg/ml (7.9-14.9), 11.4 µg/ml (8.1-15.2) and 10.9 µg/ml (7.9-15.6) at V1, V2 and V3, respectively. In univariate analysis, we failed to identify factors predictive of low drug levels. CONCLUSIONS: IFX drug levels are quite stable within 14-day treatment cycle, without trough levels in CD patients in remission during the maintenance therapy with CT-P13 sc. In patients with inactive CD under maintenance therapy with CT-P13 sc, therapeutic drug monitoring of IFX can be performed at any time between two CT-P13 sc injections.

Therapeutic drug monitoring of biologics in inflammatory bowel disease: unmet needs and future perspectives.

Therapeutic drug monitoring (TDM) has emerged as a useful tool for optimising the use of biologics, and in particular anti-tumour necrosis factor (anti-TNF) therapy, in inflammatory bowel disease (IBD). However, challenges remain and are hindering the widespread implementation of TDM in clinical practice. These barriers include identification of the optimal drug concentration to target, the lag time between sampling and results, and the proper interpretation of anti-drug antibody titres among different assays. Solutions to overcome these barriers include the harmonisation of TDM assays and the use of point-of-care testing. Other unmet needs include well designed prospective studies and randomised controlled trials focusing on proactive TDM, particularly during induction therapy. Future studies should also investigate the utility of TDM for biologics other than anti-TNF therapies in both IBD and other immune-mediated inflammatory diseases such as rheumatoid arthritis and psoriasis, and the use of pharmacokinetic modelling dashboards and pharmacogenetics towards individual personalised medicine.

Swapping Versus Dose Optimization in Patients Losing Response to Adalimumab With Adequate Drug Levels.

BACKGROUND: In cases of loss of response due to mechanistic failure under antitumor necrosis factor agents, it is recommended to switch to another class of biologics. Two different strategies were compared in patients with inflammatory bowel disease (IBD) who were treated with nonoptimized adalimumab (ADA) and experienced a loss of response despite therapeutic trough levels of adalimuma-either ADA dose optimization or switching to vedolizumab or ustekinumab. METHODS: Patients under maintenance therapy with ADA monotherapy (40 mg every 14 days) and who experienced a secondary loss of response with trough levels > 4.9 µg/mL were included prospectively in this nonrandomized study. The primary end point was the survival rate without therapeutic discontinuation after ADA dose optimization or switching to another class of biologics. RESULTS: Adalimumab was optimized (n = 61 patients, 42 Crohn's disease, 19 ulcerative colitis) or swapped for vedolizumab (n = 40, 20 ulcerative colitis) or ustekinumab (n = 30, 30 Crohn's disease). At 24 months, 11 out of 70 patients (14.8%) in the swap group discontinued treatment compared with 36 out of 61 (59.6%) patients in the optimization group (P < 0.001). The median time without therapeutic discontinuation was significantly longer in the swap group (>24 months) than in the optimization group (13.3 months, P < 0.001). In the optimization group, treatment discontinuation was positively associated with baseline fecal calprotectin >500 µg/g (HR, 3.53; 95% CI, 1.16-10.72; P = 0.026) and inversely associated with variation of trough levels of adalimumab (>2 µg/mL from baseline to week 8 after optimization; HR, 0.51; 95% CI, 0.13-0.82; P = 0.03). In the swap group, no factor was associated with treatment discontinuation. CONCLUSION: In IBD patients under ADA maintenance therapy who experience a secondary loss of response and in whom trough levels are >4.9µg/mL, swapping to another class is better than optimizing ADA, which is, however, appropriate in a subgroup of patients.

YAP/TAZ: Key Players for Rheumatoid Arthritis Severity by Driving Fibroblast Like Synoviocytes Phenotype and Fibro-Inflammatory Response.

Objective: The role of YAP/TAZ, two transcriptional co-activators involved in several cancers, was investigated in rheumatoid arthritis (RA). Methods: Fibroblast like synoviocytes (FLS) from patients with RA or osteoarthritis were cultured in 2D or into 3D synovial organoids. Arthritis rat model (n=28) and colitis mouse model (n=21) were used. YAP/TAZ transcriptional activity was inhibited by verteporfin (VP). Multiple techniques were used to assess gene and/or protein expression and/or localization, cell phenotype (invasion, proliferation, apoptosis), bone erosion, and synovial stiffness. Results: YAP/TAZ were transcriptionally active in arthritis (19-fold increase for CTGF expression, a YAP target gene, in RA vs. OA organoids; p<0.05). Stiff support of culture or pro-inflammatory cytokines further enhanced YAP/TAZ transcriptional activity in RA FLS. Inhibiting YAP/TAZ transcriptional activity with VP restored a common phenotype in RA FLS with a decrease in apoptosis resistance, proliferation, invasion, and inflammatory response. Consequently, VP blunted hyperplasic lining layer formation in RA synovial organoids. In vivo, VP treatment strongly reduced arthritis severity (mean arthritic index at 3.1 in arthritic group vs. 2.0 in VP treated group; p<0.01) by restoring synovial homeostasis and decreasing systemic inflammation. YAP/TAZ transcriptional activity also enhanced synovial membrane stiffening in vivo, thus creating a vicious loop with the maintenance of YAP/TAZ activation over time in FLS. YAP/TAZ inhibition was also effective in another inflammatory model of mouse colitis. Conclusion: Our work reveals that YAP/TAZ were critical factors during arthritis. Thus, their transcriptional inhibition could be relevant to treat inflammatory related diseases.

Dose optimisation for Loss of Response to Vedolizumab- Pharmacokinetics and Immune Mechanisms.

BACKGROUND: Real life data regarding pharmacokinetics of vedolizumab in patients needing dose optimisation are scarce. We set to examine whether pre-optimisation vedolizumab levels associate with therapy outcomes and which mechanisms explain the associations. METHODS: A multicentre observational study assessed the outcome of dose increase in association with pre-escalation levels in vedolizumab-treated patients. SubsequentIy, α4ß7 occupancy on peripheral blood [PB] and intestinal lamina propria [LP] tissues was investigated on various cellular subsets in patients undergoing lower endoscopy on infusion day. Cellular localisation of vedolizumab-bound α4ß7 and effects on M1 and M2 macrophages were also explored. RESULTS: A total of 161 inflammatory bowel disease [IBD] patients were included. Among 129/161 patients intensified during maintenance [Week 14 onward], pre-intensification trough levels were comparable or higher among those subsequently attaining post-optimisation clinical, biomarker, and endoscopic remission, compared with non-remitting patients [p = 0.09, 0.25, 0.04, respectively]. Similar results were demonstrated for those dose-optimised during induction [Week 6, n = 32]. In the immune sub-study [n = 43], free α4ß7 receptors at trough were similarly low among patients with/without mucosal healing, on PB T cells [p = 0.15], LP T cells [p = 0.88], and on PB eosinophils [p = 0.08]. Integrin receptors on M1 and M2 macrophages were also saturated by low levels of vedolizumab and anti-inflammatory cytokine secretion was not increased. Co-localisation and dissociation experiments demonstrated membranal α4ß7 receptors of two origins: non-internalised and newly generated α4ß7, but re-binding was still complete at very low concentrations. CONCLUSIONS: These results do not support pharmacokinetics as the mechanism responsible for loss of response to vedolizumab, nor do they support a need for higher drug concentration to enhance vedolizumab's immune effects. Higher pre-escalation levels may indicate less clearance [less severe disease] and higher likelihood of subsequent re-gained response, regardless of therapy escalation.

Early detection of anti-drug antibodies during initiation of anti-tumour necrosis factor therapy predicts treatment discontinuation in inflammatory bowel disease.

BACKGROUND: Anti-drug antibodies develop mostly during the induction therapy with anti-tumour necrosis factor (TNF) drugs and can be revealed by means of a drug-tolerant assay. AIM: To investigate whether the early detection of anti-drug antibodies during the induction therapy was predictive of treatment discontinuation. METHODS: In a prospective study, consecutive patients with inflammatory bowel disease (IBD), who should start an anti-TNF, were enrolled and followed regularly during 24 months or less in case of non- or loss of response (LOR) or adverse events requiring treatment discontinuation. Anti-TNF levels and anti-drug antibodies were measured at week 2 for adalimumab (ADA) and weeks 2 and 6 for infliximab (IFX) using a drug-tolerant assay. RESULTS: One hundred and eight patients were enrolled (54 under ADA). At week 2, antibodies to ADA and to IFX were detected in 76% and 67% of patients. Time to treatment discontinuation was significantly shorter (P < 0.001) in patients with antibodies to ADA ≥2.0 µg/mL-eq (6.0 vs 24 months, HR = 18.51, 95% CI [4.35-78.71]) or with antibodies to IFX ≥4.0 µg/mL-eq (5.5 vs >24 months, HR = 13.89, 95% CI [4.08-47.31]) at week 2 compared to patients without positive antibodies. Antibodies to ADA and to IFX were predictive of treatment failure within 24 months with a sensitivity of 79% and 62%, and specificities and positive predictive values of 100%. In multivariate analysis, antibodies to ADA or to IFX at week 2 were the only factors associated with treatment discontinuation. CONCLUSIONS: The prevalence of antibodies to anti-TNF is high when detected early using a drug-tolerant assay, and their appearance predicts further treatment discontinuation.

NOD2 deficiency increases retrograde transport of secretory IgA complexes in Crohn's disease.

Intestinal microfold cells are the primary pathway for translocation of secretory IgA (SIgA)-pathogen complexes to gut-associated lymphoid tissue. Uptake of SIgA/commensals complexes is important for priming adaptive immunity in the mucosa. This study aims to explore the effect of SIgA retrograde transport of immune complexes in Crohn's disease (CD). Here we report a significant increase of SIgA transport in CD patients with NOD2-mutation compared to CD patients without NOD2 mutation and/or healthy individuals. NOD2 has an effect in the IgA transport through human and mouse M cells by downregulating Dectin-1 and Siglec-5 expression, two receptors involved in retrograde transport. These findings define a mechanism of NOD2-mediated regulation of mucosal responses to intestinal microbiota, which is involved in CD intestinal inflammation and dysbiosis.