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Despite the therapeutic efficacy of Ustekinumab (UST) in Crohn's disease (CD), loss of response (LOR) is observed over time. This study aims to evaluate the impact of the UST pharmacokinetics (PK) at induction on clinical and endoscopic outcomes, as well as to find predictive markers of UST response.This retrospective study included 80 CD patients. Pharmacokinetics data (trough levels (TLs)) combined with clinical and biological parameters were fed into tailored logistic regression and tree-based ensemble techniques to predict clinical and endoscopic outcomes at one year of follow-up.TLs at week 16 were significantly lower among patients with moderate to severe endoscopic activity during the follow-up (p = 0.04). The best model to predict endoscopic outcome was obtained at week 16 by Random Forest with an area under the receiver operating characteristic curve of 0.92 ± 0.08, sensitivity 91% and specificity 75%, with key inputs such as lymphocyte and monocyte counts at week 8, and UST TLs and CRP at week 16.This real-world study confirms the relationship between early UST TLs and both clinical and endoscopic outcomes. Models were developed for the task of predicting clinical and endoscopic remission in CD patients treated with UST, highlighting the clinical relevance of UST TLs at week 16.

Real-world studies on the use of biologics in psoriasis (Pso) are increasing, but still scarce. Trough concentrations (CTo report on IL-17i effectiveness, treatment modifications, and CData was collected from IL-17i treated Pso patients followed up in the PsoPlus clinic at the Dermatology department, Ghent University Hospital, Belgium. Descriptive statistics and Kaplan-Meier analysis were performed.A total of 111 patients were included, counting for 134 IL-17i courses (secukinumab, ixekizumab, and brodalumab). Fifty-five percent of the patients were bio-naive prior to IL-17i initiation. During maintenance, merely 97.0% and 77% achieved near-complete and complete skin clearance, respectively. Major reasons for treatment modification were: suboptimal response (63.0%) and safety issues (9.3%). Reported modifications were: switch (25.4%), dose escalation (11.9%), dose de-escalation (6.7%), treatment association (6.0%), and IL-17i stop (3.0%). Overall drug survival was 69.0 months, without difference between the different IL-17i (p=0.078). Ixekizumab tended to have the highest survival. Drug survival was higher in bio-naive subjects compared to bio-experienced subjects (p=0.011). CThis real-world study showed that IL-17i are very effective drugs for Pso, with ixekizumab as leading biologic. Prior bio-experience seemed to impact IL-17i drug survival. Treatment modifications were mainly performed in case of insufficient response, primarily via switch and dose escalation, and least frequently in ixekizumab patients. C

Supplementary methods

Combination of the mTORC1/2 inhibitor TAK-228 and the PI3K-α inhibitor alpelisib inhibits EMC041 tumor growth to the same extent as BEZ235

Immunohistochemistry stainings of potential targets.

High-grade endometrial stromal sarcoma with YMHAE/NUTM2A/B fusion and cyclin D1 expression.

Purpose: Uterine sarcomas are rare and heterogeneous tumors characterized by an aggressive clinical behavior. Their high rates of recurrence and mortality point to the urgent need for novel targeted therapies and alternative treatment strategies. However, no molecular prognostic or predictive biomarkers are available so far to guide choice and modality of treatment.Experimental Design: We investigated the expression of several druggable targets (phospho-S6S240 ribosomal protein, PTEN, PDGFR-α, ERBB2, and EGFR) in a large cohort of human uterine sarcoma samples (288), including leiomyosarcomas, low-grade and high-grade endometrial stromal sarcomas, undifferentiated uterine sarcomas, and adenosarcomas, together with 15 smooth muscle tumors of uncertain malignant potential (STUMP), 52 benign uterine stromal tumors, and 41 normal uterine tissues. The potential therapeutic value of the most promising target, p-S6S240, was tested in patient-derived xenograft (PDX) leiomyosarcoma models.Results: In uterine sarcomas and STUMPs, S6S240 phosphorylation (reflecting mTOR pathway activation) was associated with higher grade (P = 0.001) and recurrence (P = 0.019), as shown by logistic regression. In addition, p-S6S240 correlated with shorter progression-free survival (P = 0.034). Treatment with a dual PI3K/mTOR inhibitor significantly reduced tumor growth in 4 of 5 leiomyosarcoma PDX models (with tumor shrinkage in 2 models). Remarkably, the 4 responding models showed basal p-S6S240 expression, whereas the nonresponding model was scored as negative, suggesting a role for p-S6S240 in response prediction to PI3K/mTOR inhibition.Conclusions: Dual PI3K/mTOR inhibition represents an effective therapeutic strategy in uterine leiomyosarcoma, and p-S6S240 expression is a potential predictive biomarker for response to treatment. Clin Cancer Res; 23(5); 1274–85. ©2017 AACR.

Supplementary tables and figure legends

Survival of uterine sarcoma patients according to tumor grade and histologic subtype.

Extracellular vesicles (EVs) have attracted great attention as potential biomarkers for cancer diagnostics. Although several technologies have been developed for EV detection, many of them are still not applicable to clinical settings as they rely on complex EV isolation processes, while lacking sensitivity, specificity or standardization. To solve this problem, we have developed a sensitive breast cancer-specific EV detection bioassay directly in blood plasma using a fiber-optic surface plasmon resonance (FO-SPR) biosensor, previously calibrated with recombinant EVs. First, we established a sandwich bioassay to detect SK-BR-3 EVs by functionalizing the FO-SPR probes with anti-HER2 antibodies. A calibration curve was built using an anti-HER2/Banti-CD9 combination, resulting in an LOD of 2.1 × 107 particles/mL in buffer and 7 × 108 particles/mL in blood plasma. Next, we investigated the potential of the bioassay to detect MCF7 EVs in blood plasma using an anti-EpCAM/Banti-mix combination, obtaining an LOD of 1.1 × 10 8 particles/mL. Finally, the specificity of the bioassay was proven by the absence of signal when testing plasma samples from 10 healthy people unknown to be diagnosed with breast cancer. The remarkable sensitivity and specificity of the developed sandwich bioassay together with the advantages of the standardized FO-SPR biosensor highlight outstanding potential for the future of EV analysis. ispartof: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES vol:24 issue:4 ispartof: location:Switzerland status: published

Background and AimsAdequate infliximab concentrations during induction treatment are predictive for deep remission [corticosteroid-free clinical and endoscopic remission] at 6 months in children with inflammatory bowel diseases [IBD]. Under standard infliximab induction dosing, children often have low infliximab trough concentrations. Model-informed precision dosing [MIPD; i.e. model-based therapeutic drug monitoring] is advocated as a promising infliximab dosing strategy. We aimed to develop and validate an MIPD framework for guiding paediatric infliximab induction treatment.MethodsData from 31 children with IBD [4–18 years] receiving standard infliximab induction dosing (5 mg/kg at week [w]0, w2 and w6) were repurposed. Eight paediatric population pharmacokinetic models were evaluated. Modelling and simulation were used to identify exposure targets, identify an optimal sampling strategy, and develop a multi-model prediction algorithm for implementation into an MIPD software tool. A role for infliximab clearance monitoring was evaluated.ResultsA 7.5 mg/L infliximab concentration target at w12 was associated with 64% probability of deep remission at 6 months. With standard dosing, less than 80% of simulated children ConclusionsA freely available, multi-model MIPD tool facilitates infliximab induction dosing and improves deep remission rates in children with IBD.

Dried blood spot (DBS) sampling by finger-pricking has recently gained a lot of interest as an alternative sample collection method. The reduced invasiveness, requirement of lower sample volumes and suitability for long-term storage at room temperature make DBS ideal for use in home settings or low-resource environments. However, traditional protocols often suffer from biased analysis data due to variable and not exactly known blood volumes present in the samples. In this work, a novel device has been developed to split-off precisely metered volumes from a blood drop and load them on pre-cut filter paper. Hereto, hydrophobic burst valves (HBV) were developed to temporarily retain a fluid flow, configurable to burst at pressures within a range of 175-600 Pa. By combining HBVs with different burst pressures, a volume metering system was developed to allow parallel metering of multiple pre-defined sample volumes. The system was shown to be accurate and consistent for blood volumes between 5-15 μL and for hematocrit levels spanning the range of 25-70%. Finally, a point-of-care DBS sampling device was developed combining the self-powered microfluidic SIMPLE technology. To evaluate the system's practical applicability, a validation study in the context of therapeutic drug monitoring of biologicals was performed using adalimumab-spiked blood samples. Microfluidic DBS samples showed good performance compared to the traditional DBS method with improved recovery rates (86% over 62%). This innovative metering system, allowing for parallelization and integration with complex liquid manipulations, will greatly impact the field of robust sampling, sample preparation, storage and analysis at the point-of-care.

BACKGROUND: Despite the favourable efficacy profile of secukinumab, clinicians encounter varying clinical responses among patients potentially associated with under- and overdosing. As biologics are expensive, their rational use is crucial and evident. Therapeutic drug monitoring could guide clinicians in making decisions about treatment modifications. AIM: In this multicentre, prospective study, we aimed to develop and validate a secukinumab immunoassay and searched for the therapeutic window in patients with psoriasis. METHODS: We determined secukinumab concentrations at trough in sera from 78 patients with psoriasis at multiple timepoints (Weeks 12, 24, 36, 48 and 52; after Week 52, measurements could be taken at an additional three timepoints) during maintenance phase, using an in-house secukinumab immunoassay consisting of a combination of MA-SEC66A2 as capture antibody and MA-SEC67A9, conjugated to horseradish peroxidase, as detecting antibody. At each hospital visit, disease severity was assessed using the Psoriasis Area and Severity Index (PASI). RESULTS: After quantification, 121 serum samples were included for dose-response analysis. Based on a linear mixed-effects model, secukinumab trough concentrations were found to decrease with increasing body mass index (BMI). Based on receiver operating characteristic (ROC) analysis, we concluded that the minimal effective secukinumab threshold was 39.1 mg/L in steady state, and that this was associated with a 92.7% probability of having an optimal clinical response (PASI ≤ 2 or reduction in PASI of ≥ 90%). CONCLUSIONS: Monitoring and targeting a secukinumab trough concentration of 39.1 mg/L may be a viable treatment option in suboptimal responders. In patients with higher BMI, weight-based dosing may be needed in order to prevent underdosing. ispartof: CLINICAL AND EXPERIMENTAL DERMATOLOGY vol:47 issue:7 pages:1324-1336 ispartof: location:England status: published

Background Histo-endoscopic outcomes are being proposed as new treatment targets in ulcerative colitis [UC]. Little is known about the pharmacokinetic-pharmacodynnamic [PK-PD] relationship of ustekinumab [UST] in UC patients or whether serum UST concentrations reflect tissue drug exposure. We aimed to study UST serum concentrations and their relation to tissue exposure and drug effectiveness in a real-world setting. Methods A total of 42 UC patients starting UST were prospectively followed by clinical, endoscopic and histological assessments at Week 16. Histological remission was defined as Nancy Histology Index of 0. Analogous to the UNIFI programme, histo-endoscopic mucosal improvement was defined as a combination of histological improvement [Geboes ≤3.1] and endoscopic improvement [MES ≤1]. Paired trough serum samples and colonic mucosal biopsies were collected for UST levels measurement. Results After 16 weeks [IQR 15.8–16.4] of therapy, histological remission and histo-endoscopic mucosal improvement were observed in 19 [45%] and 18 [43%] patients, respectively. Patients who achieved these outcomes had higher serum UST levels than those who did not. Patients with shorter disease duration and clinical response at Week 8 had higher odds to achieve histological remission. UST concentrations from paired serum and biopsy samples revealed a strong positive correlation [r = 0.88, p < 0.001], in both inflamed and uninflamed tissue. Conclusions In this real-world cohort of refractory UC patients initiating UST, more than a third of the patients achieved histological remission. A drug exposure-response relationship was observed for histo-endoscopic outcomes, with no added value of measuring tissue exposure given the strong correlation with serum exposure.

ispartof: CLINICAL GASTROENTEROLOGY AND HEPATOLOGY vol:21 issue:3 pages:838-+ ispartof: location:United States status: published

Biologicals introduced a major shift in the treatment of patients suffering from inflammatory bowel diseases. Despite providing a tight disease control for many patients, a considerable proportion of patients will fail to respond favorably to treatment or will lose response over time. Therapeutic drug monitoring emerged as a valuable tool to guide clinical decision making as serum drug concentrations have been linked to outcomes. Focusing on mucosal healing as the ultimate treatment goal, different drug concentration thresholds to achieve this outcome have been identified in the literature and are summarized in this review. For therapeutic drug monitoring to be successful in guiding clinical decision making, the used assay, the sampling time point, and the outcome that is aimed for should be taken into account when interpreting drug concentration thresholds. Awareness of these essential aspects among clinicians will improve the implementation of therapeutic drug monitoring and aid in making an evidence-based decision. ispartof: Clinical Pharmacology & Therapeutics vol:106 issue:5 pages:945-954 ispartof: location:United States status: published

A multiplex assay for the quantitation of immunoglobulin G (IgG) serum antibodies directed against Clostridium tetani toxin (TT), Corynebacterium diphtheriae toxoid (DTxd), and the Bordetella pertussis antigens pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (Prn) was developed on an Evalution® platform to enhance the evaluation of the specific antibody response towards protein antigens in suspected humoral immunodeficiencies. Evalution® is a microfluidic and microparticle-based platform with the possibility to analyse single samples and to perform real-time kinetic measurements of antibody binding. All individual antigens were covalently linked to the carboxylated microparticles after which samples and fluorescently labelled detection antibodies were flowed over the microparticles in the microfluidic channels of the assay cartridges of the system. The developed assay showed very good sensitivity, specificity, and intra- and inter-assay coefficients of variation (CVs for the different antigens between 1.72-3.53% and 3.54‐5.79%, respectively). Furthermore, the correlation of the Evalution pentaplex with a Luminex pentaplex using a panel of 48 human serum samples was excellent, with Spearman correlation coefficients between 0.936 for PT and 0.982 for DTxd (p < 0.0001 for all). Finally, we showed in a proof-of-concept experiment the potential of the Evalution® platform to simultaneously measure concentrations and binding kinetics (as a surrogate for avidity) of the IgG antibodies to the selected protein antigens. Overall, these findings show that this new Evalution pentaplex can accurately measure the antibody response to TT, DTxd, PT, FHA and Prn. It also has the potential to measure antibody binding and dissociation kinetics. ispartof: Journal Of Immunological Methods vol:503 ispartof: location:Netherlands status: Published online

Disease treatment with advanced biological therapies such as adalimumab (ADM), although largely 16beneficial,is still costly and suffersfrom loss of response. To tackle these aspects, therapeutic drug 17monitoring (TDM) isproposed toimprove treatment dosing and efficacy, but is often associated 18with long sampling-to-result workflows. Here, we presentan in-house constructed ADM-sensor, 19allowing TDM of ADMat the doctor’s office. This biosensor brings fiber optic surface plasmon 20resonance (FO-SPR),combined with self-powered microfluidics,to a point of care (POC)settingfor 21the first time. AfterdevelopingarapidFO-SPR sandwich bioassayfor ADMdetection on a 22commercial FO-SPR device, this bioassay wasimplemented onthefully-integratedADM-sensor. For 23thelatter, wecombined (I) agold coated fiber optic (FO) probe for bioassay implementationand (II) 24an FO-SPR readout system with(III) the self-powered iSIMPLE microfluidic technologyempowering25plasma sample and reagent mixingon the-cartridge as well asconnectiontothe FO-SPR readout 26system. With a calculated limit of detection (LOD)of 0.35 μg/mL in undiluted plasma, and a total 27time-to-result (TTR)within12 min, this innovative biosensor demonstrated acomparable 28performance to existing POC biosensorsfor ADM quantification in patient plasma samples, while29requiringonly 1 μL of plasma. Whereas this study demonstratesgreat potential for FO-SPR 30biosensing at the POCusing ADM as a model case,italso showshugepotential for bedside TDM of 31other drugs(e.g.other immunosuppressants, anti-epileptics and antibiotics), as the bioassay is 32highly amenable to adaptation. ispartof: Biosensors & Bioelectronics vol:206 ispartof: location:England status: Published online

Background and Aims Some patients with ulcerative colitis [UC] do not respond to vedolizumab treatment despite adequate drug exposure in serum. This study aimed to investigate vedolizumab in tissue and questioned whether insufficient tissue exposure could explain non-response in UC patients with adequate serum vedolizumab concentrations. Methods A paired serum sample and colonic mucosal biopsy was collected from 40 UC patients [20 endoscopic responders, 20 non-responders] at week 14 of vedolizumab treatment. Vedolizumab, soluble [s]-mucosal addressin cell adhesion molecule-1 [MAdCAM-1], s-vascular cell adhesion molecule-1 [VCAM-1] and s-intercellular adhesion molecule-1 [ICAM-1] were measured in serum and/or tissue. Endoscopic response was defined as Mayo endoscopic sub-score ≤1. Results A significant positive correlation was observed between vedolizumab serum and colonic tissue concentrations [ρ = 0.84, p < 0.0001], regardless of the macroscopic inflammatory state of the tissue. Vedolizumab tissue concentrations were lower in non-responders than in responders [0.07 vs 0.11 µg/mg, p = 0.04]. In the subgroup of patients with adequate vedolizumab serum concentrations [>14.6 µg/mL], tissue vedolizumab was not significantly different between responders and non-responders [0.15 vs 0.13 µg/mg; p = 0.92]. Serum sMAdCAM-1 concentrations, but not serum sICAM-1 or sVCAM-1 concentrations, were significantly higher in responders than in non-responders with adequate vedolizumab serum concentrations [1.04 vs 0.83 ng/mL, p = 0.03]. Conclusions Vedolizumab concentrations in colonic mucosal tissue of UC patients reflect the concentration in serum regardless of the macroscopic inflammatory state of the tissue. Our data show that insufficient tissue exposure does not explain non-response in UC patients with adequate serum vedolizumab concentrations.

Aims Controversies regarding infliximab treatment in elderly patients with inflammatory bowel diseases remain. We evaluated the effect of patient's age on infliximab exposure, efficacy and safety. Methods Retrospective case-control data of patients receiving infliximab induction treatment were analysed. A population pharmacokinetic model was developed to estimate individual pharmacokinetic parameters. A logistic regression model was used to investigate the effect of exposure on endoscopic remission. Repeated time-to-event models were developed to describe the hazard of safety events over time. Results A total of 104 patients (46 elderly, >= 65 years) were included. A two-compartment population pharmacokinetic model with linear elimination adequately described the data. Infliximab clearance decreased with older age, higher serum albumin, lower fat-free mass, lower C-reactive protein and absence of immunogenicity. Yet, infliximab exposure was not significantly different between elderly and nonelderly. Regardless of age, an infliximab trough concentration at week (w)14 of 15.6 mg/L was associated with a 50% probability of attaining endoscopic remission between w6 and w22. Infliximab exposure during induction treatment was not a risk factor of (severe) adverse events. The hazard of severe adverse events and malignancy increased by 2% and 7%, respectively, with increasing year of age. Concomitant immunomodulator use increased the hazard of infection by 958%, regardless of age. Conclusions Elderly patients attained infliximab exposure and endoscopic remission similarly to nonelderly patients. Therefore, the same infliximab trough concentration target can be used in therapeutic drug monitoring. The hazards of severe adverse events and malignancy increased with age, but not with infliximab exposure.

BACKGROUND & AIMS: Little is known about the relationship between ustekinumab exposure during the first 2 weeks of treatment and outcomes of patients with Crohn's disease (CD). We investigated the relationship between serum concentrations of ustekinumab during the first 2 weeks of treatment and endoscopic and biochemical remission in patients with CD. METHODS: In a prospective observational study, we measured concentrations of ustekinumab in serum samples from 41 consecutive patients who started treatment with ustekinumab (approximately 6 mg/kg, intravenously, then 90 mg every 8 weeks), due to endoscopic markers of active CD, at a single center from October 2017 through January 2019. We measured ustekinumab exposure parameters during the first 2 weeks (peak concentration measured immediately after intravenous infusion, week 2 concentration, and area under the curve through week 2). We investigated the correlation between these parameters and endoscopic remission (simple endoscopic score for CD scores of 3 or less without ulceration, assessed centrally) and biochemical remission (level of fecal calprotectin below 100 mg/kg) using the Mann-Whitney U test. RESULTS: Endoscopic remission was achieved in 10 patients (24.4%) at week 24; biochemical remission was achieved in 17 patients (41.5%) at week 8, 17 patients (41.5%) at week 16, and 21 patients (51.2%) at week 24. Peak concentrations associated with endoscopic remission (area under the receiver operating characteristic curve, 0.717; 95% CI, 0.517-0.916); 6 of 13 patients (46%) with peak concentrations above 105 μg/mL (upper tercile) achieved endoscopic remission, compared with only 1 of 14 patients (7%) with peak concentrations below 88 μg/mL (lower tercile). All exposure parameters during the first 2 weeks were associated with biochemical remission. There was no significant difference between the associations of peak concentrations, week-2 concentrations, area under the curve through week 2, or later exposure measures (at weeks 4 and 8) with biochemical or endoscopic remission. CONCLUSIONS: In a prospective study, we found that serum concentrations of ustekinumab as early as 1 hour after intravenous infusion might be used to identify patients with CD most likely to achieve endoscopic remission. This early measurement might be used to optimize treatment of CD. ispartof: CLINICAL GASTROENTEROLOGY AND HEPATOLOGY vol:19 issue:1 pages:111-+ ispartof: location:United States status: published

An association between vedolizumab (VDZ) trough concentrations and therapeutic outcome has been observed in patients with inflammatory bowel diseases. VDZ samples are typically collected via venous sampling for therapeutic drug monitoring (TDM), but can alternatively be collected via dried blood spot (DBS) samples, which can be used for intensive sampling to investigate pharmacokinetic profiles. Therefore, we have developed a DBS method for determining VDZ concentrations and validated this method by comparing VDZ measurements in paired DBS and venous patient samples. First, VDZ was spiked in citrated whole blood and spotted on filter paper. After drying, DBS were extracted and VDZ concentrations were determined in the extracts using ELISA. For clinical validation, 41 paired DBS and serum samples were collected from 19 VDZ-treated patients. VDZ concentrations measured in DBS extracts strongly correlated with serum concentrations (Pearson r = 0.978, p

As human Tau undergoes pathologically relevant post-translational modifications when expressed in yeast, the use of humanized yeast models for the generation of novel Tau monoclonal antibodies has previously been proven to be successful. In this study, human Tau2N4R-ΔK280 purified from yeast was used for the immunization of mice and subsequent selection of high affinity Tau-specific monoclonal antibodies. The characterization of four novel antibodies in different Tau model systems yielded a phosphorylation-dependent antibody (15A10), an antibody directed to the first microtubule-binding repeat domain (16B12), a carboxy-terminal antibody (20G10) and an antibody targeting an epitope on the hinge of the first and second amino-terminal insert (18F12). The latter was found to be conformation-dependent, suggesting structural differences between the Tau splicing isoforms and allowing insight in the roles played by the amino-terminal inserts. As this monoclonal antibody also has the capacity to detect tangle-like structures in different transgenic Tau mice and neurofibrillary tangles in brain sections of patients diagnosed with Alzheimer's disease, we also tested the diagnostic potential of 18F12 in a pilot study and found this monoclonal antibody to have the ability to discriminate Alzheimer's disease patients from control individuals based on increased Tau levels in the cerebrospinal fluid. ispartof: Frontiers In Molecular Biosciences vol:7 ispartof: location:Switzerland status: Published online

Background Therapeutic drug monitoring (TDM) is a diagnostic tool in the monitoring of anti-TNF therapies. Yet, the benefit for TDM of new biologics such as ustekinumab (USK) is still controversial in real-world experiences. Methods This monocentric retrospective study aims to correlate USK trough levels (TLs) with clinical and endoscopic data. All patients have given written consent to the Biobank (B2011/005). Endoscopic disease was defined as quiescent in absence of endoscopic lesions, mild disease in presence of few superficial ulcerations, moderate in presence of several ulcers and severe in presence of numerous deep ulcers and/or inflammatory stenosis. 313 serum USK samples from 67 Crohn’s disease patients were used to measure USK TL (USK ELISA, apDia) while 88 samples (at week 16, and before and after optimisation) were used to measure anti-drug antibody (ADA), using a drug-tolerant affinity capture elution anti-ustekinumab assay Results Demographic and baseline data of our population are presented in Table 1. The median follow-up was 73 weeks (IQR 39–92). An optimisation due to loss of response was required in 44.8% of patients (n = 30) after a median time of 38 weeks (IQR 24–55). To evaluate the drug efficacy, an endoscopy was performed in 61% of cases at a median time of 35 weeks (IQR 27–47). TLs were 5.2 µg/ml (IQR 2.1–8.8), 1.7 µg/ml (IQR 0.3–4.3) and 2.6 µg/ml (IQR 0.6–4.1) at week 8, 16 and 24, respectively. TLs at week 8 were correlated to the induction IV dose administrated (r = 0.3, p = 0.03). At week 16, low TLs were associated with higher endoscopic activity in the follow-up (p = 0.02), although this was not the case at week 8 (p = 0.5) (Figure 1). Patients not requiring an optimisation had higher TLs in maintenance than patients requiring optimisation (2.45 µg/ml (IQR 1.3–4.4) vs. 1.15 µg/ml (IQR 0.1–2.24), p = 0.008). Obviously, optimisation significantly increased TLs (1.15 µg/ml (IQR 0.1–2.24) vs. 6.6 µg/ml (IQR 2.3–11.3), p < 0.001). ADA were undetectable in all the measured samples in maintenance. Conclusion This real-world experience confirms a drug exposure-endoscopic response relationship. Week 16 seems to be an appropriate time point to monitor drug exposure. Earlier USK TLs, at week 8, appear less valuable to be monitored due to the influence of initial IV dose. The absence of immunogenicity suggests that it is not a key driver in the loss of response.

Background Adequate infliximab (IFX) trough concentrations (TCs) during induction treatment are predictive for long-term clinical and endoscopic remission in paediatric patients with inflammatory bowel diseases (IBD). However, under the approved weight-based dosing (5 mg/kg), children often have low IFX TCs, since the relationship between bodyweight and the IFX pharmacokinetic (PK) parameters is nonlinear. Therefore, there is a need to optimise paediatric dosing to engage optimal IFX TCs during induction treatment. Methods Fifty-two paediatric patients with IBD (34 Crohn’s disease (CD), 18 ulcerative colitis (UC)) contributed IFX samples (246 intermediate and 150 trough samples) during either induction treatment (n=32) or maintenance treatment (n=20). A population PK (popPK) model was developed to describe the relationship between IFX dose and exposure. The previously published IFX popPK model based on data of 112 children with CD in the Phase 3 REACH trial was used as a frequentist prior to inform parameter estimation using NONMEM. Our popPK model was used to simulate IFX TCs during induction treatment under different induction dosing regimens (5 mg/kg, 7.5 mg/kg, and 10 mg/kg IFX at weeks 0, 2, and 6). Probabilities of TC target attainment (PTA) were compared. The TC target, associated with a 75% probability of achieving deep remission (DR) at six months after initiating IFX treatment, was identified using a logistic regression model and a ROC analysis. DR was defined as combined endoscopic remission (Simple Endoscopic Score for CD Results The median boyweight was 44 kg (range 15-92 kg). A 2-compartment popPK model with first-order elimination described IFX concentrations well (Table 1). The IFX clearance by weight increased with decreasing bodyweight, decreasing serum albumin and absence of immunomodulator combo-therapy. Also, the IFX volume of distribution in the central and peripheral compartment by weight increased with decreasing bodyweight. A total of 18/32 (56%) patients in the induction treatment achieved DR at six months. An IFX TC of 23.0 mg/L at week 6 was identified as the TC target (100% sen, 33% spe, 100% npv, and 50% ppv). Children with a bodyweight less than 30 kg could only reach a 50% PTA when receiving 10 mg/kg IFX combo-therapy during induction (Figure 1). While children with a bodyweight above 30 kg had more than 50% PTA when receiving either 10 mg/kg IFX monotherapy or 7.5 mg/kg IFX combo-therapy (Table 2). Conclusion IFX doses higher than 5 mg/kg are needed during induction in children with IBD to facilitate the attainment of the TC target, thereby increasing the chance of long-term DR.

Background and goals Active inflammatory bowel diseases (IBD) represent an independent risk factor for venous thromboembolism. The authors investigated the hemostatic profile of IBD patients before and after induction treatment with infliximab, vedolizumab, and methylprednisolone. Study This prospective study included 62 patients with active IBD starting infliximab, vedolizumab, and/or methylprednisolone, and 22 healthy controls (HC). Plasma was collected before (w0) and after induction therapy (w14). Using a clot lysis assay, amplitude (marker for clot intensity), time to peak (Tmax; marker for clot formation rate), area under the curve (AUC; global marker for coagulation/fibrinolysis), and 50% clot lysis time (50%CLT; marker for fibrinolytic capacity) were determined. Plasminogen activator inhibitor-1 (PAI-1) and fibronectin were measured by ELISA. Clinical remission was evaluated at w14. Results At baseline, AUC, amplitude, and 50%CLT were significantly higher in IBD patients as compared with HC. In 34 remitters, AUC [165 (103-229)% vs. 97 (78-147)%, P=0.001], amplitude [119 (99-163)% vs. 95 (82-117)%, P=0.002], and 50%CLT [122 (94-146)% vs. 100 (87-129)%, P=0.001] decreased significantly and even normalized to the HC level. Vedolizumab trough concentration correlated inversely to fibronectin concentration (r, -0.732; P=0.002). The increase in Tmax for infliximab-treated remitters was significantly different from the decrease in Tmax for vedolizumab-treated remitters (P=0.028). The 50%CLT increased (P=0.038) when remitters were concomitantly treated with methylprednisolone. Conclusions Control of inflammation using infliximab most strongly reduced those parameters that are associated with a higher risk of venous thromboembolism.

Background Several studies have reported an association between ustekinumab serum concentrations and clinical outcomes, suggesting a potential role of therapeutic drug monitoring (TDM) for guiding clinical decision-making and treatment optimisation in ustekinumab-treated patients with inflammatory bowel diseases. Usually, ustekinumab concentrations are measured with an enzyme-linked immunosorbent assay (ELISA). Disadvantages of using ELISA for TDM are the rather long time-to-result and the necessity of collecting multiple samples in order to reduce the price per determination. The performance of TDM could be further enhanced by using a rapid point-of-care assay, which would allow immediate and individualised dose optimisation based on real-time pharmacokinetic information instead of awaiting dose adjustments at the subsequent administration. Methods A fiber-optic surface plasmon resonance (FO-SPR) assay was developed on a White FOx 1.0 device (FOx Biosystems), using a monoclonal antibody (MA)/MA sandwich approach. MA-UST56A2D11 was covalently immobilised to a gold-sputtered fiber surface to capture ustekinumab. After incubation with the serum sample, biotinylated MA-UST56C1H12 was used for detection of bound ustekinumab, and the signal was amplified using a polyclonal anti-biotin antibody conjugated to gold nanoparticles. A calibration curve was constructed by spiking ustekinumab in 1/1000 diluted human serum. Recovery and imprecision were assessed, and the performance of the FO-SPR assay was compared with that of our previously developed in-house ELISA using twelve serum samples of ustekinumab-treated patients. Results A dose-response curve ranging from 1.25 – 40 ng/mL was obtained, allowing quantification of ustekinumab concentrations from 0.31 µg/mL (using a 1/250 dilution) up to 80 µg/mL (using a 1/2000 dilution) in serum samples. Measurement of ustekinumab-spiked samples (1 – 25 µg/mL) showed an average intra-assay recovery of 111% (range: 95-124%) and imprecision of 10% (range: 8-15%), and an average inter-assay recovery of 109% (range: 100-122%) and imprecision of 5% (range: 1-8%). Comparison of measurements between FO-SPR and ELISA revealed a very good correlation (Pearson r coefficient of 0.980, 95% CI 0.928-0.995, p Conclusion A rapid FO-SPR assay for quantification of ustekinumab concentrations in serum samples was established and showed a very good correlation with ELISA. The reduced assay time and the possibility of measuring a single sample are advantages compared to ELISA, and may allow implementation of FO-SPR as a point-of-care diagnostic tool.

About 40 - 50% of cutaneous melanomas have activating BRAF mutations that are reachable with targeted therapy and combined BRAF-MEK inhibition improves clinical outcomes in advanced BRAF V600E/K-mutant melanoma. Three combinations are FDA-approved for this indication: dabrafenib-trametinib, vemurafenib-cobimetinib and encorafenib-binimetinib. The K601E mutation comprises approximately 3% of BRAF mutations in patients with melanoma. This article is protected by copyright. All rights reserved. ispartof: BRITISH JOURNAL OF DERMATOLOGY vol:180 issue:2 pages:421-422 ispartof: location:England status: published

Background Data remain scarce in terms of efficacy and safety of infliximab (IFX) treatment in elderly patients with inflammatory bowel disease.1 Our aim was to employ a population pharmacokinetic (popPK) model to improve our understanding of factors impacting variability in IFX exposure in elderly patients with ulcerative colitis (UC) and Crohn’s disease (CD). Methods IFX concentration–time data during induction therapy (week 2, 6 and 14) of 104 patients were obtained from a retrospective case–control study2 (n = 79) and a single centre database search (n = 25) at our institution. Patients ≥65 years old were categorised as elderly. A popPK model was developed using NONMEM 7.4. Relationships between IFX exposure and the first endoscopic remission (ER) assessment after the start of IFX therapy (absence of ulceration [CD] and Mayo endoscopic sub-score ≤0 [UC]) were evaluated. Results Median age was 62 years (IQR 38–68). A total of 46 of 104 patients (44%) were elderly. A one-compartment model with linear clearance showed adequate descriptive and predictive ability. The estimated popPK parameters (typical value [%RSE]) were clearance CL (0.346 l/day [4%]) and volume of distribution V (6.42 l [5%]). The elimination half-life of IFX in the elderly was not significantly different from the non-elderly (12.6 days vs. 11.4 days, p = 0.356). IFX clearance was higher with the presence of antibodies to IFX (ATI; drug-tolerant assay; 32% higher), higher fat-free mass (FFM; 1.4% per kg), lower serum albumin (4.5% per g/l), and younger age (0.6% per year). These covariates explained 10% of interindividual variability (IIV) in IFX CL. However, 33% of the variability remained unexplained. Contrary to Paul et al.3, proportions of patients with ATI were not significantly different between elderly and non-elderly (13% [6/46] vs. 14% [8/58], p = 1.000). FFM and serum albumin were significantly lower in elderly patients (p = 0.007 and p = 0.0004, respectively). Due to the large remaining IIV, IFX exposures (trough concentrations and estimated area under the PK curve) were not significantly different between elderly and non-elderly (Figure 1). A total of 19/72 patients (26%, 32/104 had no endoscopy data) achieved ER. There was no significant difference between the proportion of elderly and non-elderly with ER (p = 1.000). IFX trough concentrations at w6 were significantly higher in patients achieving ER (p = 0.016). Conclusion Older age is an independent predictor of lower clearance. However, the effect of age did not pronounce on infliximab exposure in our elderly patient cohort as a result of confounding effects of fat-free mass and serum albumin. References

Background Multiple studies have reported the association between vedolizumab serum concentrations and endoscopic outcomes in patients with ulcerative colitis (UC). However, little is known about drug consumption in tissue and the relationship with mucosal inflammation. This study aimed to investigate vedolizumab concentrations in the tissue of UC patients and the correlation with their inflammatory state and serum levels. Methods A paired serum sample and colonic mucosal biopsy were collected in 36 UC patients at week 14 of vedolizumab treatment. In non-responders, defined as a Mayo endoscopic subscore of ≥2, inflamed colonic biopsies were taken in the sigmoid around 20–30 cm from the anal verge. In responders, defined as a Mayo endoscopic subscore ≤ 1, a biopsy was taken in a macroscopically uninflamed area at the same location. Biopsies were lysed by the addition of 10 μl lysis buffer (50 mM Tris, 0.1% Triton X-100 and 100 mM NaCl) per mg tissue and vortexed every 5 min during 1 h. Total protein content was measured and normalised to 3 mg/ml before analysis of the vedolizumab concentration using an in-house developed ELISA. Results are expressed as µg vedolizumab/mg total protein content. Results A positive correlation was observed between vedolizumab concentrations in tissue and serum (Spearman r = 0.8447, p < 0.0001), both in inflamed (r = 0.8609, p Conclusion Vedolizumab concentrations in colonic mucosal tissue of UC patients inversely correlate with the severity of inflammation. As the serum-to-tissue ratio of vedolizumab is numerically higher in non-responders compared with responders, the relative distribution of vedolizumab in serum and tissue might be more important than the drug concentration alone.

Background Loss of response (LOR) to infliximab (IFX) remains a challenge in routine management of IBD patients. We evaluated IFX high-resolution pharmacokinetics (PK) during induction with intermediate and peak PK levels. Methods This is a prospective, multicentre (n = 9), interventional study approved by EC (P2017/484). Fourteen blood samples were collected per patient from baseline to week 30. All patients were IFX naïve with active disease according to clinical, biological and endoscopy criteria. The primary outcome evaluated the inter-individual variability of IFX PK during induction and correlation with remission at week 30. In addition to trough levels (TLs), intermediate (ILs) and peak levels (PLs) were also measured and defined as drug level between two infusions and drug level early on after infusion (+2h), respectively. Remission was defined as having a Harvey Bradshaw Index (HBI) ≤ 4 and C-Reactive Protein (CRP) ≤5 for Crohn’s disease (CD), and as a clinical Mayo score ≤2 and faecal calprotectin Results Demographic and baseline data of the study population are presented in Table 1. Among the 62 patients enrolled, 33.9% of patients (n = 21/62) were in remission at week 30. Eight patients dropped out due to disease worsening. Median TLs at week 6 were higher among patients in clinical remission at week 30 (p = 0.02) confirming previous observations. However, ILs at day 3 as well as PLs after the third infusion were also significantly higher in patients in clinical remission at week 30 (Figure 1a–c). ATI were detected as soon as week 6. At week 2, infliximab levels were significantly lower among patients in which ATI developed at a later time point (p = 0.006) and this observation was confirmed when measuring ILs at day 17 (p = 0.002), TLs at week 6 (p = 0.002) and ILs at week 10 (p = 0.001). Conclusion This multicentre prospective study demonstrates that intermediate levels as early as day 3 predict remission at week 30 in IBD patients. Low IFX levels during induction were correlated to future ATI development. PK modelling may allow to better select patients early on for sustained remission with infliximab.

Objective. Endometrial carcinoma (EC) is the sixth most common cancer in women and therapies are limited for advanced and recurrent disease. Patient-derived tumor xenograft (PDTX) models are becoming popular tools in translational research because of their histological and genetic similarity to the original tumors and the ability to predict therapeutic response to treatments. Here, we established and characterized a panel of 24 EC PDTX models which includes the major histological and genetic subtypes observed in patients. Methods. Fresh tumor tissues collected from primary, metastatic and recurrent type I and type II EC patients were engrafted in immunocompromised mice. Histology, vimentin, and cytokeratin expression were evaluated, together with Microsatellite instability (MSI), mutation profiling by Whole Exome Sequencing and copy number profiling by Whole Genome Low Coverage Sequencing. The efficacy of both PI3K and MEK inhibitors was evaluated in a model of endometrioid carcinoma harboring PTEN, PIK3CA and KRAS mutations. Results. We observed good similarity between primary tumors and the corresponding xenografts, at histological and genetic level. Among the engrafted endometrioid models, we found a significant enrichment of MSI and POLE mutated tumors, compared to non-engrafted samples. Combination treatment with NVP-EZ235 and AZD6244 showed the possibility to stabilize the tumor growth in one model originated from a patient who already received several lines of chemotherapy. Conclusion. The established EC PDTX models, resembling the original human tumors, promise to be useful for preclinical evaluation of novel combination and targeted therapies in specific EC subgroups. (C) 2015 Elsevier Inc. All rights reserved

Purpose: Uterine sarcomas are rare and heterogeneous tumors characterized by an aggressive clinical behavior. Their high rates of recurrence and mortality point to the urgent need for novel targeted therapies and alternative treatment strategies. However, no molecular prognostic or predictive biomarkers are available so far to guide choice and modality of treatment. Experimental Design: We investigated the expression of several druggable targets (phospho-S6S240 ribosomal protein, PTEN, PDGFR-α, ERBB2, and EGFR) in a large cohort of human uterine sarcoma samples (288), including leiomyosarcomas, low-grade and high-grade endometrial stromal sarcomas, undifferentiated uterine sarcomas, and adenosarcomas, together with 15 smooth muscle tumors of uncertain malignant potential (STUMP), 52 benign uterine stromal tumors, and 41 normal uterine tissues. The potential therapeutic value of the most promising target, p-S6S240, was tested in patient-derived xenograft (PDX) leiomyosarcoma models. Results: In uterine sarcomas and STUMPs, S6S240 phosphorylation (reflecting mTOR pathway activation) was associated with higher grade (P = 0.001) and recurrence (P = 0.019), as shown by logistic regression. In addition, p-S6S240 correlated with shorter progression-free survival (P = 0.034). Treatment with a dual PI3K/mTOR inhibitor significantly reduced tumor growth in 4 of 5 leiomyosarcoma PDX models (with tumor shrinkage in 2 models). Remarkably, the 4 responding models showed basal p-S6S240 expression, whereas the nonresponding model was scored as negative, suggesting a role for p-S6S240 in response prediction to PI3K/mTOR inhibition. Conclusions: Dual PI3K/mTOR inhibition represents an effective therapeutic strategy in uterine leiomyosarcoma, and p-S6S240 expression is a potential predictive biomarker for response to treatment. Clin Cancer Res; 23(5); 1274–85. ©2017 AACR.

Background Therapeutic drug monitoring of ustekinumab (UST), a monoclonal antibody directed against the p40 subunit of IL12/23, can serve as a tool to identify underexposed Crohn’s disease (CD) patients, as UST concentrations have been linked to treatment response. Drug concentrations are most often measured when a patient is losing response. To reduce the risk of loss of response, drug concentrations could be measured upfront to predict the chance of achieving response later on and optimising treatment if necessary. Identification of the optimal time point to measure UST levels that have a predictive value for long-term outcome requires studies with multiple sampling. Dried blood spot (DBS) sampling allows convenient and remote collection of a blood drop through a small finger prick. The current study aimed to develop and validate the DBS method in order to identify the best time point to measure UST concentrations to predict long-term outcome in CD patients and explore the pharmacokinetic profile. Methods UST concentrations (0.2–80 μg/ml) were spiked in citrated whole blood and 40 μl was spotted onto protein saver cards. After punching a 6mm disc, DBS was extracted and the UST concentration was measured with an in-house developed MA-UST56A2D11/MA-UST56C1H12 ELISA. The extraction efficiency, accuracy, precision and the effect of anti-UST antibodies on UST detection were evaluated. Additionally, the effect of the spotted blood volume, the stability of the DBS card at room temperature (RT) and DBS extract at -20°C was examined. To evaluate the correlation between UST in DBS extracts and serum, DBS and serum were simultaneously collected from 8 UST-treated CD patients at two different time points. Results Spiking UST to citrated whole blood and subsequent spotting and extraction revealed an average extraction efficiency of 65 ± 9% (n = 11). The accuracy and imprecision of all concentrations tested were 92–109% and 11–18%, respectively. Addition of anti-UST antibodies to spiked UST samples caused a similar decrease in UST concentration in DBS extracts as in serum. Spotted blood volumes between 15 and 50 μl demonstrated similar recoveries. Storing the DBS card at RT for up to 2 weeks and DBS extract at -20°C for 2 months did not impair recovery. UST concentrations in DBS extracts (range: 0.55–12.1 μg/ml) from CD patients correlated strongly with those in serum (Pearson r = 0.982, p < 0.0001). Conclusion DBS is a robust method that facilitates multiple sampling for the determination of UST concentrations in CD patients. To explore the pharmacokinetic profile of UST and identify the best time point during induction to predict the long-term outcome, a prospective study in which multiple DBS are collected in active CD patients initiating UST is warranted.

Diaphragm dysfunction develops during severe sepsis as a consequence of hemodynamic, metabolic, and intrinsic abnormalities. Similarly, 12 hours of controlled mechanical ventilation also promotes diaphragm dysfunction. Importantly, patients with sepsis are often treated with mechanical ventilation for several days. It is unknown if controlled mechanical ventilation exacerbates sepsis-induced diaphragm dysfunction, and this forms the basis for these experiments. We investigate the effects of 12-hour controlled mechanical ventilation on contractile function, fiber dimension, cytokine production, proteolysis, autophagy, and oxidative stress in the diaphragm of septic rats.Randomized controlled experiment.Animal research laboratory.Adult male Wistar rats.Treatment with a single intraperitoneal injection of either saline or Escherichia coli lipopolysaccharide (5 mg/kg). After 12 hours, the saline-treated animals (controlled mechanical ventilation) and half of the septic animals (lipopolysaccharide + controlled mechanical ventilation) were submitted to 12 hours of controlled mechanical ventilation while the remaining septic animals (lipopolysaccharide) were breathing spontaneously for 12 hours. They were compared to a control group. All animals were studied 24 hours after saline or lipopolysaccharide administration.Twenty-four hours after saline or lipopolysaccharide administration, diaphragm contractility was measured in vitro. We also measured diaphragm muscle fiber dimensions from stained cross sections, and inflammatory cytokines were determined by proteome array. Activities of calpain, caspase-3, and proteasome, expression of 20S-proteasome α subunits, E2 conjugases, E3 ligases, and autophagy were measured with immunoblotting and quantitative polymerase chain reaction. Lipopolysaccharide and/or controlled mechanical ventilation independently decreased diaphragm contractility and fiber dimensions and increased diaphragm interleukin-6 production, protein ubiquitination, expression of Atrogin-1 and Murf-1, calpain and caspase-3 activities, autophagy, and protein oxidation. Compared with lipopolysaccharide alone, lipopolysaccharide + controlled mechanical ventilation worsened diaphragm contractile dysfunction, augmented diaphragm interleukin-6 levels, autophagy, and protein oxidation, but exerted no exacerbating effects on diaphragm fiber dimensions, calpain, caspase-3, or proteasome activation.Twelve hours of controlled mechanical ventilation potentiates sepsis-induced diaphragm dysfunction, possibly due to increased proinflammatory cytokine production and autophagy and worsening of oxidative stress.