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Monitoring of anti-drug antibodies in patients on ustekinumab is not routinely recommended in patients with inflammatory bowel disease (IBD) due to low rates of immunogenicity. Aim of study: The purpose of this study was to investigate the relationship between anti-drug antibodies detected by a drug-tolerant assay and loss of response (LOR) to therapy in a cohort of patients with IBD being treated with ustekinumab. Patients and Methods: This retrospective study consecutively enrolled all adult patients with moderate to severe active IBD who had at least 2 years of follow-up after ustekinumab was initiated. LOR was defined as CDAI > 220 or HBI > 4 for Crohn’s disease (CD) and partial Mayo subscore > 3 for ulcerative colitis (UC) and with a modification in disease management. Results: Ninety patients were included (78 CD and 12 UC; mean age 37 years). Median levels of anti-ustekinumab antibodies (ATU) were significantly higher in patients with LOR compared to those with ongoing clinical response (15.2 µg/mL-eq CI (7.9–21.5) and 4.7 µg/mL-eq CI (2.1–10.5), respectively; p = 0.04). The area under the ROC curve (AUROC) for ATU in predicting LOR was 0.76. The optimal cut-off point for identifying patients with LOR was 9.5 µg/mL-eq with a sensitivity of 80% and specificity of 85%. Uni- and multivariate analyses showed that serum ATU ≥ 9.5 µg/mL-eq (hazard ratio (HR) 2.54, 95%CI (1.80–5.93)), p = 0.022, prior vedolizumab (HR 2.78, 95%CI (1.09–3.34), p = 0.019) and prior azathioprine (HR 0.54, 95%CI (0.20–0.76), p = 0.014) exposures were the only factors independently associated with LOR to UST. Conclusion: In our real-life cohort, ATU was identified as an independent predictor of LOR to ustekinumab in patients with IBD.

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.

Severe COVID-19 is associated with a high circulating level of calprotectin, the S100A8/S100A9 alarmin heterodimer. Baseline calprotectin amount measured in peripheral blood at diagnosis correlates with disease severity. The optimal use of this biomarker along COVID-19 course remains to be delineated.We focused on patients with a WHO-defined moderate COVID-19 requiring hospitalization in a medical ward. We collected plasma and serum from three independent cohorts (N = 626 patients) and measured calprotectin amount at admission. We performed longitudinal measures of calprotectin in 457 of these patients (1461 samples) and used a joint latent class mixture model in which classes were defined by age, body mass index and comorbidities to identify calprotectin trajectories predicting the risk of transfer into an intensive care unit or death.After adjustment for age, sex, body mass index and comorbidities, the predictive value of baseline calprotectin in patients with moderate COVID19 could be refined by serial monitoring of the biomarker. We discriminated three calprotectin trajectories associated with low, moderate, and high risk of poor outcome, and we designed an algorithm available as online software (https://calpla.gustaveroussy.fr:8443/) to monitor the probability of a poor outcome in individual patients with moderate COVID-19.These results emphasize the clinical interest of serial monitoring of calprotectin amount in the peripheral blood to anticipate the risk of poor outcomes in patients with moderate COVID-19 hospitalized in a standard care unit.The study received support (research grants) from ThermoFisher immunodiagnostics (France) and Gustave Roussy Foundation.

The objective of the study was to evaluate whether Point-of-Care (POC) assays are equivalent to ELISAs for measuring residual trough levels of adalimumab (ADA) in a cohort of Inflammatory Bowel Disease (IBD) patients. ADA trough levels obtained by POC assays were used to optimize patients in daily clinical practice. Different assays (three ELISAs (Enzyme-Linked ImmunoSorbent Assay) from two different suppliers and two POC assays) were compared to measure ADA trough levels in a first cohort of 31 IBD patients. All assays revealed a high correlation within the assays, ranging from 0.86 to 0.99. Cut-off values were always higher with ELISAs than with POC assays. Then, a small prospective clinical study with a second cohort of 37 IBD patients was performed to compare POC assays and ELISAs for their ability to optimize patients on the basis of the measured ADA trough levels. The use of a POC assay to monitor ADA trough levels did not improve the follow-up of patients with loss of response, as they were always optimized whatever their ADA residual rate. For patients in clinical remission, a POC assay can be useful in some clinical situations to maintain or de-escalate ADA doses according to the measured trough levels. In conclusion, different assays for ADA monitoring are quite equivalent. A POC assay could be only useful for a proactive strategy for asymptomatic patients with a sub-therapeutic dose of ADA, but new therapeutic thresholds need to be identified.

Background Two scores have shown their interest in evaluating the luminal activity of CD in magnetic resonance (MR), the MARIA and Clermont scores, but their calculation can be complicated in clinical practice. Recently, the Spanish authors validated a new simplified MARIA score (MARIAs) and retrospectively showed a very good correlation with the initial MARIA score (1). The purpose of this study was to validate this correlation in an independent cohort and to compare its feasibility with other scores. Methods This was a retrospective analysis of all MR performed in our department to evaluate the luminal activity of CD. Two independent radiologists each calculated the MARIA, Clermont and MARIAs scores (wall thickness > 3mm, oedema, comb sign, ulcerations), each blind to the other and blind to clinical activity. In case of disagreement between the two radiologists, a third reader analyzed MR activity. Correlations were calculated between these three tests for the entire cohort. In addition, concordance tests were performed for predetermined thresholds of 7 to 11 for the MARIA score, 8.5 to 12.5 for the Clermont score and 1 to 2 for the MARIAs score. The duration of the analysis was reported for each reading. Isolated colonic CD were excluded from the study. Results One hundred and twenty-one CD were included (65 in clinical and biological activity, 33% ileal phenotype, mean age: 38.5 years, sex ratio M/F = 54.5%). The agreement between the MARIA score between 7 and 11, the Clermont score between 8.5 and 12.5 and the MARIAs score between 1 and 2 was 0.92 (Fleiss kappa test). The correlation between the MARIA score and its simplified score was very strong (r = 0.93; 95% CI: 0.9–0.95) as well as between the Clermont score and the MARIAs score (r = 0.92 95% CI: 0.89–0.95). Inter-observer agreement was significantly higher in the calculation of the MARIAs score (96%) compared with 80% for the MARIA and Clermont scores (p = 0.04). Reading time was significantly faster for the MARIAs score (3.45 ± 0.4 min) compared with the MARIA (10.05 ± 1.2 min) and Clermont (13.5 ± −3.5 min) scores (p < 0.01). Positive predictive values for deep remission (clinical remission and calprotectin < 250 µg/g stool) were 95% at thresholds Conclusion In this independent cohort, we confirm the very strong correlation between the simplified MARIA score and the two reference scores (MARIA and Clermont) in the analysis of MC luminal activity as well as its rapid calculation and strong inter-observer agreement.

International audience; Background: Vedolizumab (VDZ), a humanized monoclonal antibody targeting α4β7 integrin, is effective in induction and maintenance therapy in patients with inflammatory bowel disease (IBD) who have not adequately responded to standard therapies, and high levels of vedolizumab trough levels (VTL) have been associated with clinical remission. The α4β7 integrin binds to endothelial MAdCAM-1 and is up-regulated by retinoic acid (RA). Aim: To determine the relations between soluble MAdCAM-1 (sMAdCAM-1) and RA concentrations with clinical remission during VDZ maintenance therapy. Methods: In a retrospective study performed in IBD patients treated with VDZ we measured VTL, sMAdCAM-1 and RA concentrations. Results: Among the 62 included patients (38 Crohn's disease) 24 relapsed and 38 stayed in remission between weeks 10 to 30 after VDZ initiation. During this maintenance therapy, median values of VTL and RA were 15.4 \textmug/mL and 0.97 ng/mL, whereas sMAdCAM-1 was undetectable (\textless 0.41 ng/mL) in 67.3% of samples. The positive predictive value (PPV) of undetectable sMAdCAM-1 for clinical remission was 80.0% with a corresponding sensitivity of 74.6%. On multivariate analysis undetectable sMAdCAM-1 and high VTL (\textgreater 19 \textmug/mL) were independently associated with clinical remission (OR=7.5, p=0.006 and OR=2.2, p=0.045, respectively). The combination of sMAdCAM-1 \textless 0.41 ng/mL and VTL \textgreater 19 \textmug/mL was the best pharmacokinetic profile with a PPV of 95.2%. Median values of sMAdCAM-1 and RA were significantly higher (p=0.0001) before VDZ therapy than during the follow-up (sMAdCAM-1: 40.5 vs \textless 0.41 ng/mL; RA: 1.7 vs 0.97 ng/mL). Only RA \textgreater 1.86 ng/mL before VDZ therapy was predictive of clinical remission during the follow-up (AUROC=80.7%). Conclusions: Undetectable sMAdCAM-1 appears strongly associated with clinical remission during VDZ maintenance therapy. Combination of undetectable sMAdCAM-1 with high VTL is also potentially interesting for therapeutic drug monitoring. Baseline RA concentrations are predictive of clinical remission. These findings need to be confirmed in further prospective studies.

Background Nearly 40% of patients who failed on ADA have therapeutic residual trough levels (pharmacodynamic failure). It is then recommended to change the therapeutic class to a non-anti-TNF biological. In this situation, however, a quarter of patients respond to an ADA dose optimisation. The purpose of this work was to compare these two strategies and identify predictors of response for each strategy. Methods This is a bi-centre, retrospective study based on a clinical and biological database that included patients followed from 2015 to 2016 with an IBD in maintenance treatment with ADA as monotherapy (40 mg/sc/14 days) and in loss of response (CDAI > 220 with faecal calprotectin > 250 µg/g stool for CD and Mayo score > 6 with endoscopic sub-score > 1 for UC). All patients included had residual trough ADA levels > 5 µg/ml. Relapsed patients were treated either with dose optimisation (ADA: 40 mg/sc/7 days) or other biotherapy (ustekinumab or vedolizumab, according to classic regimens and dosages). The primary endpoint was the relapse-free survival rate (defined as clinical and biological or endoscopic activity requiring therapeutic change). The survival curve analysis was performed using the Kaplan–Meier method and the log-rank test. Results In total, 125 patients (mean age: 38 years, 75% CD, sex ratio M/F = 57%, previous infliximab = 42%) were included and 50 were treated with another biological (Vedolizumab: 30 patients, Ustekinumab: 20 patients). The characteristics of the two groups were comparable except for significantly higher levels of CRP and faecal calprotectin at inclusion in the biological change arm. The duration without relapse was significantly longer after the class change (p = 0.0005; HR = 0.39[0.23–0.68]). The relapse-free survival rates at 54 weeks were 35% for the optimised arm and 66% for a class change (p = 0.04). In multivariate analysis, the only long-term response predictor was biotherapy class change vs. ADA dose optimisation (p = 0.042; HR = 0.3[0.02–0.95]). Previous use of IFX or type of IBD were not associated with relapse. For the dose optimisation strategy, in multivariate analysis, only age < 40 years was associated with a progression without relapse (p = 0.007; HR = 0.09[0.01–0.52]). Residual ADA levels were not predictive of response to optimisation (p = 0.73) and no ADA quartile was significantly associated with a more favourable clinical response. For the class change strategy, no relapse predictors were isolated in univariate analysis. Conclusion In patients on ADA who are losing response despite therapeutic rates, the change of class to non-anti-TNF biotherapy allows a significantly greater lasting response than a dose optimisation strategy for ADA.

Background Several studies have shown a link between circulating anti-TNF levels during induction and clinical progression during IBD. There are less data on the detection of anti-drug antibodies at induction because it requires the use of so-called ‘drug-tolerant’ techniques. The purpose of our study was to investigate in two distinct cohorts (IBD patients on IFX or ADA) whether the early appearance of anti-drug antibodies measured using a drug-tolerant test was associated with clinical progression. Methods In a retrospective study, we included all patients followed in our department for at least 3 months and having had an anti-TNF dosage from W2 of induction under ADA or IFX. At follow-up, therapeutic failure was defined by the obligation to optimise, a change in biotherapy, the use of corticosteroids or surgery. IFX and ADA levels were measured routinely (Lisa-Tracker; Theradiag) and anti-medicine antibodies were detected by ‘drug-sensitive’ ELISA technique (Lisa-Tracker; Theradiag) or ‘drug-tolerant’ as previously described [1]. Patients with a positive rheumatoid factor were excluded. Results 54 patients were included in ADA (mean age: 36 years, sex ratio M/F = 54%, CD: 65%, combotherapy: 10%) and 54 treated with IFX (mean age: 35 years, sex ratio M/F: 46%, CD: 62%, combotherapy: 65%). The search for anti-drug antibodies to W2 using a ‘drug-sensitive’ technique did not reveal any antibodies, whereas 74% of patients on ADA (AAA > or = 2.5 µg/ml eq) and 55% of patients on IFX (ATI > or = 4µg/ml eq). Under ADA, the duration of treatment until loss of response was significantly shorter in the presence of AAA at W2: 6 months vs. 24 months (HR = 18.51; 95CI = 4.35–78.11; p < 0.001). In multivariate analysis, the only independent factor associated with failure was the rate of ADA antibodies to W2 (HR = 18.17; 95CI: 4.27–77.45; p < 0.001). Under IFX, the treatment time to loss of response was significantly shorter in the presence of ATI to W2 (ATI > or = 4µg/ml eq): 5.5 months vs. >24 months (HR = 13.89; 95CI = 4.08–47.31; p < 0.001). In multivariate analysis, the only independent factor associated with failure was the level of anti-IFX antibodies to W2 (> or = 4 µg/ml eq) (HR = 8.07; 95CI: 3.13–20.82; p < 0.001). The higher quartiles of ATI and AAA were significantly associated with poor outcomes (p < 0.001 for each anti-TNF). Conclusion The early onset of anti-drug antibodies in the induction phase as early as W2 is the only isolated independent factor associated with loss of response. Anti-drug antibody frequencies are very high when measured with a drug-tolerant test and these Abs may be more neutralising with ADA than with IFX.

Background In a recent prospective, randomised trial, we showed that the rates of clinical failure and occurrence of unfavourable pharmacokinetics using a drug-sensitive assay after a switch of anti-TNF were significantly higher in monotherapy compared with combination therapy (Log-rank test p < 0.0001), whatever the anti-TNF used in IBD patients. We aimed in a post hoc analysis to assess the time-course of antidrug antibodies in the two groups of patients using a drug-tolerant assay previously described (1). Methods After switching of anti-TNF under mono or combotherapy, blood samples were uptake at various time-points (6, 12, 18 and 24 months). Using a drug-tolerant assay, we defined pharmacokinetic failure when antidrug antibodies were detected (> 2.5 μg/ml Eq). Transient anti-drug antibodies were defined as antibodies that appeared during the course of anti-TNF therapy with no clinical worsening, and finally that disappeared after 2 consecutive measurements. Results Ninety patients were analysed. According to a drug-tolerant assay, the occurrence of antibodies against anti-TNF was significantly higher in patients under monotherapy (log-rank test p < 0.0001 (HR = 3.36 [1.94–5.86]) than under combination therapy. The rates of anti-drug antibody were significantly lower under IFX-AZA combotherapy compared with ADA-AZA combotherapy or under monotherapy. Monotherapy ADA (HR = 5.55[2.46–12.34]) or IFX (HR = 6.05[2.67–13.70]) and combination therapy ADA-AZA (HR = 3.34 [1.407.98]) increased significantly the rates of pharmacokinetic failure using a drug-tolerant assay compared with IFX-AZA combotherapy. The time-course without pharmacokinetic failure was significantly different between the 4 groups of patients from 15 months (p = 0.04) but was not significantly different at 6 months (p = 0.12). Overall, 9% of patients developed transient antibodies. Detection of antibodies against anti-TNF at 6 months using a drug-tolerant assay predicted significantly an immunogenic failure assessed previously by a drug-sensitive assay with a sensitivity of 57.1%, a specificity of 92.7%, a positive predictive value of 90.3%. In contrary to the association between clinical failure and immunogenic failure using drug-sensitive assay, the association of detectable drug and positive antibodies using a drug-tolerant assay was not significantly associated with clinical failure (HR = 1.3[0.3–6.8], p = 0.51). Conclusion Pharmacokinetic failure using a drug-tolerant assay was significantly lower under combotherapy, especially for IFX-AZA. Detection of anti-drug antibodies could predict pharmacokinetic failure. Reference