Infliximab desensitization in patients with inflammatory bowel diseases: a safe therapeutic alternative.

BACKGROUND: Hypersensitivity reactions (HSR) to the administration of infliximab (IFX) in Inflammatory Bowel Diseases (IBD) patients are not rare and usually lead to drug discontinuation. We report data on safety and effectiveness of desensitization to IFX in patients with previous HSR. METHODS: We conducted a retrospective monocentric observational study. Patients for whom a desensitization protocol to IFX was realized after a previous HSR were included. Anti-drug antibodies (ADA) and IFX trough levels at both inclusion and six months after desensitization were collected. Clinical outcomes, including recurrence of HSR were evaluated. RESULTS: From 2005 to 2020, 27 patients (Crohn's Disease: 26 (96%) were included). Desensitization after HSR was performed after a median time of 10.4 months (2.9-33.1). Nineteen (70%) patients received immunosuppressants at time of desensitization. Eight (30%) patients presented HSR at first (n = 2), second (n = 4) or third (n = 2) IFX perfusion after desensitization. None led to intensive care unit transfer or death. Thirteen (48%) had clinical response at 6 months and 8 (29%) were still under IFX treatment two years after desensitization. IFX trough levels and ADA were available for 14 patients at time of desensitization. Most patients (12 out of 14) had ADA at a high level. At 6 months, among the 7 patients with long term response to IFX, 4 presented a decrease of ADA titers and 2 had a significant trough level of IFX. CONCLUSION: IFX desensitization in patients with IBD is a safe therapeutic alternative and represents a potential option for patients refractory to multiple biologics.What is already known? Hypersensitivity reactions to the administration of infliximab is frequent. Occurrence of hypersensitivity reaction, either immediate or delayed, usually leads to permanent drug discontinuation.What is new here? Infliximab desensitization is well tolerated with no hypersensitivity reaction recurrence in 70% of patients. Clinical success at 6 months was of 48% and around a third of patients remained under infliximab therapy two years after desensitization. Antidrug antibodies decreased and infliximab trough levels increased in these patients showing the impact of desensitization on immunogenicity.How can this study help patient care? Infliximab desensitization represents a potential option for patients refractory to multiple biologics who presented hypersensitivity reaction to the drug.

Anti-ß7 integrin treatment impedes the recruitment on non-classical monocytes to the gut and delays macrophage-mediated intestinal wound healing.

BACKGROUND: Closing mucosal defects to reach mucosal healing is an important goal of therapy in inflammatory bowel disease (IBD). Among other cells, monocyte-derived macrophages are centrally involved in such intestinal wound healing. We had previously demonstrated that the anti-α4ß7 integrin antibody vedolizumab blocks the recruitment of non-classical monocytes as biased progenitors of wound healing macrophages to the gut and delays wound healing. However, although important for the interpretation of disappointing results in recent phase III trials in IBD, the effects of the anti-ß7 antibody etrolizumab on wound healing are unclear so far. METHODS: We analyzed the expression of etrolizumab targets on human and mouse monocyte subsets by flow cytometry and assessed their function in adhesion and homing assays. We explored wound-associated monocyte recruitment dynamics with multi-photon microscopy and compared the effects of etrolizumab and vedolizumab surrogate (-s) antibodies on experimental wound healing and wound-associated macrophage abundance. Finally, we investigated wound healing macrophage signatures in the large intestinal transcriptome of patients with Crohn's disease treated with etrolizumab. RESULTS: Human and mouse non-classical monocytes expressed more αEß7 integrin than classical monocytes and were a target of etrolizumab-s, which blocked non-classical monocyte adhesion to MAdCAM-1 and E-Cadherin as well as gut homing in vivo. Intestinal wound healing was delayed on treatment with etrolizumab-s along with a reduction of peri-lesional wound healing macrophages. Wound healing macrophage signatures in the colon of patients with Crohn's disease were substantially down-regulated on treatment with etrolizumab, but not with placebo. CONCLUSIONS: Combined blockade of αEß7 and α4ß7 with etrolizumab seems to exceed the effect of anti-α4ß7 treatment on intestinal wound healing, which might help to inform further investigations to understand the recent observations in the etrolizumab phase III trial program.

Prospective Validation of CD-62L (L-Selectin) as Marker of Durable Response to Infliximab Treatment in Patients With Inflammatory Bowel Disease: A 5-Year Clinical Follow-up.

INTRODUCTION: The development of biomarkers to guide management of anti-tumor necrosis factor (TNF) agents in patients with inflammatory bowel disease (IBD) is an unmet need. We developed an in vitro blood assay to predict patient long-term outcome with the anti-TNFα agent infliximab (IFX). METHODS: Patients with IBD were classified according to the shedding of an L-selectin (CD62L) from the surface of their granulocytes in whole blood. CD62L shedding was quantified by flow cytometry before and after drug administration. A clinical data collection from June 2012 to August 2017 with blinded IFX management was aimed at validating the long-term predictive value of this test. RESULTS: Among 33 patients with IBD (17 Crohn's disease and 5 ulcerative colitis), 22 were predicted functional responders (PFR) and 11 were predicted as nonresponders (NR) according to the in vitro test. Five years after study initiation, 72% of PFR were still treated with IFX (vs 27% in the NR group; P < 0.05), with a median time spent under IFX of 45 vs 12 months (P = 0.019), respectively. Thirty-five medicosurgical events occurred with a median time to first event of 3 vs 30 months (P = 0.023), respectively. Our assay was the best independent predictor of staying long term on IFX (P = 0.056). DISCUSSION: An assay-based in vitro test for functional blockade of TNFα (CD62L shedding) provides an excellent long-term (at 3-5 years) independent predictor of durable use of IFX in patients with IBD. Testing patients could personalize decision making to significantly reduce costs and risk of adverse events and complications.

Optimization of infliximab therapy in inflammatory bowel disease using a dashboard approach-an Indian experience.

PURPOSE: Infliximab (IFX) therapy in inflammatory bowel disease (IBD) is associated with loss of response in half the patients, due to complex pharmacokinetic and immunological factors. Dashboard's Bayesian algorithms use information from model and individual multivariate determinants of IFX concentration and can predict dose and dosing interval. AIM: To compare measured IFX concentrations in our laboratory with values predicted by iDose dashboard system and report its efficacy in managing patients not responding to conventional dosing schedule. METHOD: Clinical history, demographic details, and laboratory findings such as albumin and C-reactive protein (CRP) data of IBD patients (n = 30; median age 23 years (IQR: 14.25 - 33.5)) referred for IFX drug monitoring in our laboratory from November 2017 to November 2019 were entered in iDose software. The IFX concentration predicted by iDose based on this information was compared with that measured in our laboratory. In addition, a prospective dashboard-guided dosing was prescribed in 11 of these 30 patients not responding to conventional dosing and was followed to assess their clinical outcome. RESULT: IFX monitoring in our 30 patients had shown therapeutic concentration in 12, supratherapeutic in 2 and subtherapeutic concentration in 16 patients. The iDose predicted concentration showed concordance in 21 of these 30 patients. Of 11 patients managed with iDose-assisted prospective dosing, 8 achieved clinical remission, 2 showed partial response, and one developed antibodies. CONCLUSION: Retrospective data analysis showed concordance between laboratory measured and iDose-predicted IFX level in 70% of patients. iDose-assisted management achieved clinical remission and cost reduction.

Infliximab levels and antibodies in IBD-related peripheral arthralgia.

BACKGROUND: Extra-intestinal manifestations (EIM) are common in inflammatory bowel diseases (IBD) and may affect up to 40% of the patients during the course of the disease. Peripheral arthralgia (PA) is by far the most common EIM. To date, TNFα inhibitors are the most established treatment for EIMs in IBD. Infliximab (IFX) trough levels (TL) and anti-IFX antibodies (ATI) are correlated with multiple outcomes in IBD such as clinical response and remission, mucosal healing, fistular healing, and more. So far, a correlation between PA and IFX TL\ATI has not been evaluated. METHODS: This retrospective study included IBD patients followed by the gastroenterology department of Sheba Medical Center. Patients with active PA at onset of IFX treatment were included. IFX TL and ATI were evaluated at week 6, 14, and 26 and correlated with PA persistence. RESULTS: Forty patients (37 Crohn's and 3 ulcerative colitis) with IBD-related PA were included. The overall prevalence of PA was 55% (22/40), 42.5% (17/40), and 55% (22/40) after 6, 14, and 26 weeks, respectively. IFX trough drug levels were not associated with reported PA at week 6 [median, 11.8 µg/ml (IQR 6.6-15.5) vs 10.05 µg/ml (IQR 7.35-12.87), p = 0.56], week 14 [median, 4.7 µg/ml (IQR 2.3-7) vs 3.1 µg/ml (IQR 1.35-7.35), p = 0.55], and week 26 [median, 3 µg/ml (IQR 1.15-5.17) vs 3.4 µg/ml (IQR 0.13-6.75), p = 0.94]. Detectable ATI were significantly more prevalent in patients with PA than in patients without PA at week 26 [11/22 (50%) vs 3/18 (16.7%), p = 0.028]. CONCLUSIONS: In patients with IBD-related PA, ATI are associated with an increased risk of persistence of PA. No direct correlation was demonstrated between IFX TL and persistence of PA.

Immunological Variables Associated With Clinical and Endoscopic Response to Vedolizumab in Patients With Inflammatory Bowel Diseases.

BACKGROUND AND AIMS: Vedolizumab [VDZ] is a monoclonal antibody directed against the α4ß7 integrin heterodimer, approved for patients with inflammatory bowel diseases [IBD]. This study aimed at identifying immunological variables associated with response to vedolizumab in patients with ulcerative colitis [UC] and Crohn's disease [CD]. METHODS: This is a phase IV explorative prospective interventional trial. IBD patients received open-label VDZ at Weeks 0, 2, 6, and 14. Patients with a clinical response at Week 14 were maintained with VDZ up to Week 54. At Weeks 0 and 14, their peripheral blood was obtained and endoscopy with biopsies was performed. The Week 14 clinical response and remission, Week 54 clinical remission, and Week 14 endoscopic response were evaluated as endpoints of the study. The expression of surface markers, chemokine receptors, and α4ß7 heterodimer in peripheral blood and lamina propria lymphocytes was assessed by flow cytometry. A panel of soluble mediators was assessed in sera at baseline and at Week 14 by 45-plex. RESULTS: A total of 38 IBD patients [20 UC, 18 CD] were included in the study. At Week 14, the clinical response and remission rates were 87% and 66%, respectively. Higher baseline levels of circulating memory Th1 cells were strongly associated with clinical response at Week 14 [p = 0.0001], whereas reduced baseline levels of lamina propria memory Th17 and Th1/17 cells were associated with endoscopic response. Immunological clusters were found to be independently associated with vedolizumab outcomes at multivariable analysis. A panel of soluble markers, including IL17A, TNF, CXCL1, CCL19 for CD and G-CSF and IL7 for UC, associated with vedolizumab-induced Week 54 clinical remission. CONCLUSIONS: The results of this exploratory study uncovered a panel of circulating and mucosal immunological variables associated with response to treatment with vedolizumab.

Switching From Originator Adalimumab to the Biosimilar SB5 in Patients With Inflammatory Bowel Disease: Short-term Experience From a Single Tertiary Clinical Centre.

BACKGROUND AND AIMS: Patients' perspectives after switching from originator to biosimilar adalimumab have yet to be assessed. We evaluated the efficacy of switching from the originator adalimumab to a biosimilar compound [SB5] in patients with inflammatory bowel disease [IBD]. METHODS: Data on IBD patients who were switched from the originator to biosimilar adalimumab [SB5] at IBD Center ISCARE were analysed. Disease activity was assessed using standard clinical indices (Harvey-Bradshaw index [HBI] for Crohn's disease [CD] and partial Mayo score for ulcerative colitis [UC]), and laboratory parameters (C-reactive protein [CRP] and faecal calprotectin [FC]). Trough levels and anti-drug antibodies were measured. Patients were evaluated 10 weeks [W10] after the switch, and results were compared with the control group of patients on originator compound. RESULTS: A total of 93 patients switched to biosimilar adalimumab were included [CD 86%] and were matched to 93 controls for age, gender, diagnosis, and disease activity. There was no difference in the disease activity in either SWITCH or ORIGINATOR cohorts between Weeks 0 and 10. Similarly, no difference was found between cohorts at both prespecified time points. Moreover, no significant differences in CRP or FC concentrations were seen between W0 and W10 either in the SWITCH, or in the ORIGINATOR cohort [p >0.05]. Adalimumab serum trough levels remained stable after the switch. No new safety signals were detected. CONCLUSIONS: Our study confirmed that switching IBD patients from the originator adalimumab to a biosimilar compound [SB5] does not affect treatment efficacy.

Efficacy and Safety of Vedolizumab Subcutaneous Formulation in a Randomized Trial of Patients With Ulcerative Colitis.

BACKGROUND & AIMS: Maintenance treatment with vedolizumab, a monoclonal antibody that inhibits the gut-selective α4ß7 integrin, is administered intravenously. Some patients might prefer a subcutaneous formulation of vedolizumab for maintenance treatment. Subcutaneous vedolizumab was investigated as maintenance treatment in patients with moderately to severely active ulcerative colitis. METHODS: We performed a phase 3, double-blind, double-dummy trial at 141 sites in 29 countries from December 18, 2015 through August 21, 2018. Patients with moderately to severely active ulcerative colitis received open-label treatment with intravenous vedolizumab 300 mg at weeks 0 and 2. At week 6, patients with clinical response were randomly assigned maintenance treatment with subcutaneous vedolizumab 108 mg every 2 weeks, intravenous vedolizumab 300 mg every 8 weeks, or placebo. The primary end point was clinical remission at week 52, which was defined as a total Mayo score of ≤2 and no subscore >1. RESULTS: Among the randomized 216 patients, clinical remission at week 52 was achieved by 46.2%, 42.6%, and 14.3% of patients in the subcutaneous vedolizumab, intravenous vedolizumab, and placebo groups, respectively (subcutaneous vedolizumab vs placebo: Δ32.3%; 95% confidence interval, 19.7%-45.0%; P < .001). The subcutaneous vedolizumab group also had greater endoscopic improvement and durable clinical response at week 52 compared with placebo (both P < .001). The incidence of injection-site reactions was more frequent in patients given subcutaneous vedolizumab (10.4%) than intravenous vedolizumab (1.9%) or placebo (0%); these were not treatment limiting, most were mild, and none resulted in discontinuation. Subcutaneous and intravenous vedolizumab safety profiles were otherwise similar. CONCLUSIONS: Subcutaneous vedolizumab is effective as maintenance therapy in patients with moderately to severely active ulcerative colitis who had a clinical response to intravenous vedolizumab induction therapy. It has a favorable safety and tolerability profile. ClinicalTrials.gov ID: NCT02611830; EudraCT 2015-000480-14.

Influence of Drug Exposure on Vedolizumab-Induced Endoscopic Remission in Anti-Tumour Necrosis Factor [TNF] Naïve and Anti-TNF Exposed IBD Patients.

BACKGROUND AND OBJECTIVES: Vedolizumab has demonstrated efficacy and safety in patients with Crohn's disease [CD] and ulcerative colitis [UC]. Endoscopic outcome data are limited, especially in anti-tumour necrosis factor [TNF] naïve patients. The present study compared endoscopic outcome in anti-TNF naïve and exposed patients, and explored if this was affected by drug exposure. METHODS: We retrospectively analysed all patients initiating vedolizumab at our tertiary referral centre since 2015. For UC, endoscopic improvement was defined as a Mayo endoscopic subscore ≤1 at week 14. For CD, endoscopic remission was defined as absence of ulcerations at week 22. Vedolizumab trough concentrations were measured at week 6, week 14 and during maintenance. RESULTS: A total of 336 patients were identified [53.3% CD], 20% of them being anti-TNF naïve. Endoscopic improvement was achieved by 56.1% of UC patients and endoscopic remission by 39.1% of CD patients. Endoscopic outcomes were significantly better in anti-TNF naïve vs exposed patients [all: 67.2% vs 42.0%, p = 0.0002; UC: 74.4% vs 50.0%, p = 0.02; CD: 57.1% vs 35.8%, p = 0.03]. Achievement of endoscopic end points significantly impacted long-term treatment continuation [p = 9.7 × 10-13]. A better endoscopic outcome was associated with significantly higher drug exposure in both CD and UC. CONCLUSIONS: The results of this observational, single-centre real-life study suggest that vedolizumab may induce endoscopic remission in both CD and UC. Although anti-TNF naïve patients had a significantly better outcome, 42% of anti-TNF exposed patients still benefited endoscopically. A clear exposure-endoscopic response relationship exists, but not all patients will benefit from treatment intensification. Hence, predictive biomarkers remain necessary. PODCAST: This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast.

Proactive Monitoring of Adalimumab Trough Concentration Associated With Increased Clinical Remission in Children With Crohn's Disease Compared With Reactive Monitoring.

BACKGROUND & AIMS: Proactive monitoring of drug trough concentrations and antibodies against drugs might help determine whether patients are likely to respond to treatment and increase efficacy. We investigated whether proactive drug monitoring is associated with higher rates of clinical remission in pediatric patients with Crohn's disease (CD). METHODS: We performed a nonblinded, randomized controlled trial of 78 children with CD (6-18 years old; 29% female; mean age, 14.3 ± 2.6 years) who had not received prior treatment with a biologic agent but had responded to adalimumab induction therapy, under scheduled monitoring of clinical and biologic measures (based on clinical factors and levels of C-reactive protein and fecal calprotectin), at pediatric gastroenterology units in Israel from July 2015 through December 2018. The patients were randomly assigned to groups that received proactive monitoring (trough concentrations measured at weeks 4 and 8 and then every 8 weeks until week 72, n = 38) or reactive monitoring (physicians were informed of trough concentrations after loss of response, n = 40). In both groups, doses and intervals of adalimumab were adjusted to achieve trough concentrations of 5 µg/mL. The primary endpoint was sustained corticosteroid-free clinical remission at all visits (week 8 through week 72). RESULTS: The primary endpoint was achieved by 31 children (82%) in the proactive group and 19 children (48%) in the reactive group (P = .002). Sixteen patients in the proactive monitoring group (42%) achieved a composite outcome of sustained corticosteroid-free remission, C-reactive protein ≤0.5 mg/dL, and level of fecal calprotectin ≤150 µg/g compared with 5 patients in the reactive monitoring group (12%) (P = .003). By week 72 of treatment, 33 patients in the proactive monitoring group had received adalimumab intensification (87%) compared with 24 patients in the reactive monitoring group (60%) (P = .001). CONCLUSIONS: In a randomized controlled trial of pediatric patients with CD, we found that proactive monitoring of adalimumab trough concentrations and adjustment of doses and intervals resulted in significantly higher rates corticosteroid-free clinical remission than reactive monitoring (measuring trough concentration after loss of response). Clinicaltrials.gov no.: NCT02256462.

Infliximab Induced Cardiac Tamponade

Aim To report the first case of cardiac tamponade related to Infliximab induction therapy in an Ulcerative Colitis patient. Methods Review of published case reports. Results This complication was likely due to a type 3 hypersensitivity immune-complex reaction resulting in a reactive pericardial effusion Discussion Though rare, this case demonstrates how autoimmune reaction to anti-TNF𝛼 therapy can initially mimic infection, as our patient presented with tachycardia, hypotension, raised inflammatory and infective markers and fever.

Real World Experience With Ustekinumab in Children and Young Adults at a Tertiary Care Pediatric Inflammatory Bowel Disease Center.

BACKGROUND: Ustekinumab is an effective therapy for Crohn disease currently approved for adults. Off-label use in the pediatric population is increasing, but its effectiveness in this age group has not been reported. AIMS: The aim of the study was to describe real-world experience with ustekinumab at a tertiary care pediatric inflammatory bowel disease (IBD) center. METHODS: As part of an ongoing observational cohort study of biologic-treated pediatric IBD patients initiated in October 2014, data on demographics, disease behavior, location and activity, treatment, and surgical history were collected for all patients receiving ustekinumab. Disease activity was assessed using the Harvey Bradshaw index or partial Mayo score. Primary outcome was steroid-free remission at 52 weeks. Descriptive statistics summarized the safety and efficacy outcomes, and univariate analyses were performed to examine associations of clinical characteristics with efficacy. RESULTS: Fifty-two children and young adults initiating ustekinumab were analyzed; 81% Crohn Disease, 8% ulcerative colitis, and 11% IBD-unspecified. Median [IQR] age at induction was 16.8 [14-18] years. Patients were followed for a minimum of 12 months. Most patients (81%) failed >1 anti-TNF, and 37% failed anti-TNF and vedolizumab; 10 patients were biologic-naïve. At week 52, 75% were still on ustekinumab, and 50% (bio-exposed) and 90% (bio-naïve) were in steroid-free remission. Two infusion reactions and neither serious adverse events nor serious infections were observed. CONCLUSIONS: Our results suggest that ustekinumab is efficacious and safe in pediatric patients with IBD. Controlled clinical trial data are needed to confirm these observations.

Appropriate Therapeutic Drug Monitoring of Biologic Agents for Patients With Inflammatory Bowel Diseases.

BACKGROUND & AIMS: Therapeutic drug monitoring (TDM) is widely available for biologic therapies in patients with inflammatory bowel disease (IBD). We reviewed current data and provided expert opinion regarding the clinical utility of TDM for biologic therapies in IBD. METHODS: We used a modified Delphi method to establish consensus. A comprehensive literature review was performed regarding the use of TDM of biologic therapy in IBD and presented to international IBD specialists. Subsequently, 28 statements on the application of TDM in clinical practice were rated on a scale of 1 to 10 (1 = strongly disagree and 10 = strongly agree) by each of the panellists. Statements were accepted if 80% or more of the participants agreed with a score ≥7. The remaining statements were discussed and revised based on the available evidence followed by a second round of voting. RESULTS: The panel agreed on 24 (86%) statements. For anti-tumor necrosis factor (anti-TNF) therapies, proactive TDM was found to be appropriate after induction and at least once during maintenance therapy, but this was not the case for the other biologics. Reactive TDM was appropriate for all agents both for primary non-response and secondary loss of response. The panellists also agreed on several statements regarding TDM and appropriate drug and anti-drug antibody (ADA) concentration thresholds for biologics in specific clinical scenarios. CONCLUSION: Consensus was achieved towards the utility of TDM of biologics in IBD, particularly anti-TNF therapies. More data are needed especially on non-anti-TNF biologics to further define optimal drug concentration and ADA thresholds as these can vary depending on the therapeutic outcomes assessed.

Vedolizumab Concentrations Are Associated with Long-Term Endoscopic Remission in Patients with Inflammatory Bowel Diseases.

BACKGROUND: The aim of this study was to assess the relationship of serum vedolizumab concentrations (SVC) during induction and endoscopic remission in patients with inflammatory bowel diseases (IBD) after 52 weeks of therapy with vedolizumab. We also sought to assess the incidence of antibody to vedolizumab (ATV) formation, the effect of ATV on drug pharmacokinetics and efficacy, and identify variables associated with SVC through the first 30 weeks of treatment. METHODS: This is a prospective cohort study of patients with active IBD initiating standard therapy with vedolizumab. Collected variables included demographics, clinical disease activity, biomarkers, pre-infusion SVC, and ATV measured at weeks 2, 6, 14, 22, and 30. Primary outcome was steroid-free endoscopic remission at week 52. RESULTS: Fifty-five patients were included. Patients that achieved steroid-free endoscopic remission by week 52 had higher SVC at weeks 2, 6, 14, 22, and 30, but only achieved statistical significance at weeks 2 and 6. Only 3 out of the 55 study subjects (5.5%) had detectable ATV through the follow-up. Overall, there were a positive correlation between SVC and serum albumin and a negative correlation with C-reactive protein, fecal calprotectin, and body mass. Vedolizumab concentrations ≥ 23.2 mcg/ml at week 2 were associated with endoscopic remission at week 52 (OR 8.8 [95% CI 2.6-29.7], p < 0.001). CONCLUSIONS: Vedolizumab concentrations during induction were associated with endoscopic remission at week 52. Interventional studies looking into improved efficacy with higher drug exposure are warranted.

Causes of Treatment Failure in Children With Inflammatory Bowel Disease Treated With Infliximab: A Pharmacokinetic Study.

OBJECTIVES: Anti-tumor necrosis factor antibodies have led to a revolution in the treatment of inflammatory bowel diseases (IBD); however, a sizable proportion of patients does not respond to therapy. There is increasing evidence suggesting that treatment failure may be classified as mechanistic (pharmacodynamic), pharmacokinetic, or immune-mediated. Data regarding the contribution of these factors in children with IBD treated with infliximab (IFX) are still incomplete. The aim was to assess the causes of treatment failure in a prospective cohort of pediatric patients treated with IFX. METHODS: This observational study considered 49 pediatric (median age 14.4) IBD patients (34 Crohn disease, 15 ulcerative colitis) treated with IFX. Serum samples were collected at 6, 14, 22 and 54 weeks, before IFX infusions. IFX and anti-infliximab antibodies (AIA) were measured using enzyme linked immunosorbent assays. Disease activity was determined by Pediatric Crohn's Disease Activity Index or Pediatric Ulcerative Colitis Activity Index. RESULTS: Clinical remission, defined as a clinical score <10, was obtained by 76.3% of patients at week 14 and by 73.9% at week 54. Median trough IFX concentration was higher at all time points in patients achieving sustained clinical remission. IFX levels during maintenance correlated also with C-reactive protein, albumin, and fecal calprotectin. After multivariate analysis, IFX concentration at week 14 >3.11 µg/mL emerged as the strongest predictor of sustained clinical remission. AIA concentrations were correlated inversely with IFX concentrations and directly with adverse reactions. CONCLUSIONS: Most cases of therapeutic failure were associated with low serum drug levels. IFX trough levels at the end of induction are associated with sustained long-term response.

Utility of proactive infliximab levels in paediatric Crohn's disease.

OBJECTIVE: Infliximab (IFX) has an established role in Crohn's disease (CD), with serum trough levels of IFX (TLI) increasingly used to optimise dosing. We report the utility of routine, proactive TLI in children on combination therapy with immunosuppression (IS) from a single paediatric centre. METHODS: This is a retrospective chart review of all children with CD receiving IFX therapy conducted betweenJanuary 2014-May 2017. Clinical phenotype, duration of therapy, TLI (µg/mL), drug antibodies, type of IS, biomarkers and changes in management were recorded. RESULTS: 60 children (8-17 years; median 14.1 years) had 206 TLIs recorded. 56/60 (93%) were on IS, with 5/60 (8%) developing antidrug antibodies (ADAs). 63/206 TLIs were recorded duringan episode of relapse (median 3.0 µg/mL) vs 143/206 TLIs recorded in remission (median 5.2 µg/mL). For children with TLI <3 µg/mL, 31/63 (49%) were in relapse vs 30/143 (21%) in remission. For children with TLI >7 µg/mL, 7/63 (11%) were in relapse vs 46/143 (32%) in remission. Change in management resulted from 43/206 (21%) TLIs in 31/60 (52%) children: 21 dose escalations, 12 de-escalations and 10 changed to adalimumab. Of 31 postinduction TLIs, 15/17 (88%) children with TLI >7 µg/mL achieved clinical and biochemical remission for the duration of therapy (median 14 months), while 4/5 (80%) children with TLI <3 µg/mL required early dose escalation. Combination therapy with thiopurines (TP) (median TLI 4.9 µg/mL) versus methotrexate (MTX) (median TLI 5.2 µg/mL) achieved comparable levels with no difference in relapse frequency. CONCLUSIONS: Routine, proactive TLIs guide optimal management in children with CD. Postinduction and during maintenance, levels <3 µg/mL were associated with relapse and levels >7 µg/mL with sustained remission. Combination IS with TP and MTX appears to offer comparable TLI and ADA rates.

Immunogenicity is not the driving force of treatment failure in vedolizumab-treated inflammatory bowel disease patients.

BACKGROUND AND AIM: The pivotal GEMINI trials reported low immunogenicity of vedolizumab. However, anti-vedolizumab antibodies (AVA) are frequently underestimated because most assays are not drug-tolerant and unable to detect antidrug antibodies while there is drug in the circulation. This study aimed to explore which antidrug antibody assay is best suited to detect AVA and investigated immunogenicity of vedolizumab in inflammatory bowel disease (IBD) patients discontinuing vedolizumab therapy. METHODS: A drug-tolerant affinity capture elution (ACE) assay was developed for the measurement of AVA in the presence of vedolizumab and compared with the previously established drug-resistant and drug-sensitive assays. Vedolizumab and AVA were measured at week 6, at the last infusion, and 12-20 weeks after treatment discontinuation in a cohort of 40 vedolizumab-treated IBD patients who stopped treatment due to primary non-response, loss of response, or adverse events. RESULTS: The drug-tolerant ACE assay could detect AVA in samples that the drug-resistant and drug-sensitive assays were unable to. Using the drug-tolerant ACE assay, 3 (8%) out of 40 vedolizumab-treated IBD patients who discontinued therapy were AVA positive at week 6, whereas no AVA were detected at the last infusion nor after treatment discontinuation. Primary non-responders had numerically lower median vedolizumab concentrations at week 6 compared with patients with loss of response (20.3 vs 30.7 µg/mL, respectively, P = 0.0570). CONCLUSIONS: Immunogenicity of vedolizumab is not the driving force of treatment failure, and AVA do not increase upon treatment discontinuation in vedolizumab-treated IBD patients. Underexposure during induction might partially be responsible for primary non-response.

Comparison of Point-of-Care and Classical Immunoassays for the Monitoring Infliximab and Antibodies Against Infliximab in IBD.

OBJECTIVE: The primary objective is to assess whether the POC assays to measure infliximab residual trough level in the serum of IBD patients were non-inferior to the ELISA techniques available on the market, and to determine which of them was the most robust. The second is to compare three different ELISA kits for monitoring anti-infliximab antibodies (ATI). METHODS: The assays were carried out on patients' sera using four ELISA kits from four different suppliers (three with a monoclonal antibody and one polyclonal) and two rapid techniques provided by BÜHLMANN (Quantum Blue®) and R-Biopharm (Ridaquick) for monitoring infliximab levels. ATI were measured by three ELISA sets (Grifols, Theradiag, and R-Biopharm) which have different positivity limits and different units. RESULTS: We measured infliximab residual level and ATI in the serum of 90 IBD patients (85 treated with infliximab and five with adalimumab). All of the infliximab assays were very well correlated when analyzed with Spearman nonparametric correlation (0.93 ≤ r ≤ 0.99), and the two POC assays were also excellently correlated (r = 0.98). The ATI monitoring kits revealed a correlation ranging from 0.73 to 0.96 when comparing positive and negative patients. When normalizing the quantitative values between the different ELISA tests (expressed arbitrarily by using multiples of the positivity limits defined by each supplier), the Spearman r coefficient ranged from 0.81 to 0.93. CONCLUSION: The available evidence allows us to conclude that all of the infliximab monitoring assays correlate well and may be used for IFX monitoring; albeit variations in measured IFX concentration among different assays remain present, these assays could be interchangeable. The ATI monitoring techniques are all capable of detecting ATI-positive patients, but because of the difference in the positivity limits and the measurement units, it is better to follow a patient rate with one definite kit.

Association Between Infliximab Drug and Antibody Levels and Therapy Outcome in Pediatric Inflammatory Bowel Diseases.

OBJECTIVES: While infliximab pharmacokinetics are associated with therapy outcome in adult inflammatory bowel disease (IBD) population, limited data are available in pediatric patients. We aimed to define the relationship between infliximab trough and antibodies' levels (IFX-TL, ATI) and clinical, biomarker remission. METHODS: IFX-TL and ATI were routinely obtained between 2011 and 2017. Associations with clinical and inflammatory (C-reactive protein, CRP) end-points were studied throughout the first year of infliximab therapy. RESULTS: A total of 63 patients (50 Crohn disease, 13 ulcerative colitis, median follow-up 16 months, median 8 samples/patient) were included, and 773 sera-samples were analyzed. Sera of patients in clinical remission had higher median IFX-TLs than sera of those with active disease (4 vs 2.25 µg/mL, P < 0.0001). In addition, patients with normal CRP had a higher median IFX-TL than those with elevated CRP (P = 0.02). Moreover, IFX-TL > 9.2 µg/mL at week 2 predicted clinical remission by week 14 (sensitivity 71.4%, specificity 81.2%, area under curve (AUC) = 0.73, P = 0.02) and IFX-TL > 2.2 µg/mL at week 6 predicted infliximab retention beyond 1 year of treatment (sensitivity 88.9%, specificity 100.0%, AUC = 0.974, P < 0.0001). CONCLUSIONS: A significant association between IFX-TL and ATI and clinical and biomarker remission status in pediatric IBD patients was demonstrated, including a temporal association between week 2, 6 levels and outcome of induction and between week 6 and 14 levels and remission at 1 year of therapy. These findings suggest that therapeutic drug monitoring may be considered for management guidance among pediatric IBD patients.