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Background: The optimal dosing strategy for infliximab in steroid-refractory acute severe ulcerative colitis (ASUC) is unknown. We compared intensified and standard dose infliximab rescue strategies and explored maintenance therapies following infliximab induction in ASUC., Methods: In this open-label, multicentre, randomised controlled trial, patients aged 18 years or older from 13 Australian tertiary hospitals with intravenous steroid-refractory ASUC were randomly assigned (1:2) to receive a first dose of 10 mg/kg infliximab or 5 mg/kg infliximab (randomisation 1). Block randomisation was used and stratified by history of thiopurine exposure and study site, with allocation concealment maintained via computer-generated randomisation. Patients in the 10 mg/kg group (intensified induction strategy [IIS]) received a second dose at day 7 or earlier at the time of non-response; all patients in the 5 mg/kg group were re-randomised between day 3 and day 7 (1:1; randomisation 2) to a standard induction strategy (SIS) or accelerated induction strategy (AIS), resulting in three induction groups. Patients in the SIS group received 5 mg/kg infliximab at weeks 0, 2, and 6, with an extra 5 mg/kg dose between day 3 and day 7 if no response. Patients in the AIS group received 5 mg/kg infliximab at weeks 0, 1, and 3, with the week 1 dose increased to 10 mg/kg and given between day 3 and day 7 if no response. The primary outcome was clinical response by day 7 (reduction in Lichtiger score to <10 with a decrease of ≥3 points from baseline, improvement in rectal bleeding, and decreased stool frequency to ≤4 per day). Secondary endpoints assessed outcomes to day 7 and exploratory outcomes compared induction regimens until month 3. From month 3, maintenance therapy was selected based on treatment experience, with use of thiopurine monotherapy, combination infliximab and thiopurine, or infliximab monotherapy, with follow-up as a cohort study up to month 12. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, NCT02770040, and is completed., Findings: Between July 20, 2016, and Sept 24, 2021, 138 patients were randomly assigned (63 [46%] female and 75 [54%] male); 46 received a first dose of 10 mg/kg infliximab and 92 received 5 mg/kg infliximab. After randomisation 1, we observed no significant difference in the proportion of patients who had a clinical response by day 7 between the 10 mg/kg and 5 mg/kg groups (30 [65%] of 46 vs 56 [61%] of 92, p=0·62; risk ratio adjusted for thiopurine treatment history, 1·06 [95% CI 0·94-1·20], p=0·32). We found no significant differences in secondary endpoints including time to clinical response or change in Lichtiger score from baseline to day 7. Two patients who received 10 mg/kg infliximab underwent colectomy in the first 7 days compared with no patients in the 5 mg/kg group (p=0·21). Three serious adverse events occurred in three patients in both the 10 mg/kg group and 5 mg/kg group. After randomisation 2, the proportions of patients with clinical response at day 14 (34 [74%] of 46 in the IIS group, 35 [73%] of 48 in the AIS group, and 30 [68%] of 44 in the SIS group, p=0·81), clinical remission at month 3 (23 [50%], 25 [52%], 21 [48%], p=0·92), steroid-free remission at month 3 (19 [41%], 20 [42%], 18 [41%], p=1·0), endoscopic remission at month 3 (21 [46%], 22 [46%], 21 [48%], p=0·98), and colectomy at month 3 (three [7%] of 45, nine [19%] of 47, five [12%] of 43, p=0·20) were not significantly different between groups. Between day 8 and month 3, the proportion of patients with at least one infectious adverse event possibly related to infliximab was two (4%) of 46 in the IIS group, eight (17%) of 48 in the AIS group, and eight (18%) of 44 in the SIS group (p=0·082). No deaths occurred in the study., Interpretation: Infliximab is a safe and effective rescue therapy in ASUC. In steroid-refractory ASUC, a first dose of 10 mg/kg infliximab was not superior to 5 mg/kg infliximab in achieving clinical response by day 7. Intensified, accelerated, and standard induction regimens did not result in a significant difference in clinical response by day 14 or in remission or colectomy rates by month 3., Funding: Australian National Health and Medical Research Council, Gastroenterology Society of Australia, Gandel Philanthropy, Australian Postgraduate Award, Janssen-Cilag., Competing Interests: Declaration of interests MCC is supported by a Gandel Major Philanthropy Grant and an Australian Postgraduate Award, and has received research funding from Janssen-Cilag. CFDLWS has served as a speaker for DiaSorin, has received educational support from Pfizer, Shire, and Ferring, has received research funding from the Robert C Bulley Charitable Foundation and St Vincent's Hospital Melbourne Research Endowment Fund, and is supported by an Australian National Health and Medical Research Council (NHMRC) Postgraduate Scholarship. DC has received educational support from Viatris and is supported by an NHMRC Postgraduate Scholarship. EKW has served as a consultant, advisory board member, or speaker for AbbVie, Bristol Myers Squibb, Ferring, Janssen, Celltrion, Falk, and Takeda, is supported by an NHMRC Emerging Leadership Level 1 Fellowship, and has received research support from Ferring and Janssen. AP has served as an advisory board member or received speaker fees from AbbVie, Ferring, Janssen, Pfizer, Takeda, and Dr Falk Pharma. BC has served as a consultant, advisory board member, or speaker for AbbVie, Celltrion, Chiesi, Ferring, Janssen, Eli Lilly, MSD, Pfizer, Takeda, and Shire, and has received research support from AbbVie, Celltrion, The Gastroenterological Society of Australia, the Helmsley Charitable Trust, the NHMRC, and Takeda. WN has received educational and research support from Pfizer, AbbVie, Janssen, Shire and Ferring. JB has served as a consultant, advisory board member, or speaker for AbbVie, Ferring, Janssen, Celltrion, Chiesi, Janssen, Pfizer, Amgen, GlaxoSmithKline, Bristol Myers Squibb, Microba, Anatara, and Takeda, and has received research support from the NHMRC, United States Department of Defense, AbbVie, Janssen, Ferring, Pfizer, and Takeda. MG has served on the advisory board of Pfizer and AbbVie and has received speaker fees and research grants from Abbvie, Celltrion, Janssen, Pfizer and travel grants from Pfizer. NM has received speaker fees from Takeda and Baxter, and educational support from Baxter. DRVL has received consulting fees from AbbVie and speaker fees for Takeda. NSD reports serving as an advisory board member or speaker for AbbVie, Celltrion, Chiesi, Ferring, Janssen, Eli Lilly, MSD, Pfizer, Takeda, and Shire, and has received research support from AbbVie, Celltrion, The Gastroenterological Society of Australia, and the NHMRC. RWL reports advisory board membership for AbbVie, Aspen, Bristol Myers Squibb, Celgene, Celltrion, Chiesi, Ferring, Glutagen, Hospira, Janssen, Eli Lilly, MSD, Novartis, Pfizer, Prometheus Biosciences, and Takeda, and research grants from the University of Sydney, the McCusker Charitable Foundation, Celltrion, Shire, Janssen, Takeda, Joanna Tiddy grant, the Gastroenterological Society of Australia, the NHMRC, The Gutsy Group, and Pfizer. MPS has received educational grants or research support from Gilead and Celltrion, speaker fees from Janssen, AbbVie, Ferring, Takeda, Pfizer, Shire, Celltrion, Eli Lilly, and Dr Falk Pharma, and has served on advisory boards or received consultancy fees for Janssen, Takeda, Pfizer, Celgene, AbbVie, MSD, Emerge Health, Gilead, Bristol Myers Squibb, Celltrion, and Eli Lilly, and has received travel grants from Pfizer and Dr Falk Pharma. PDC has served as a consultant, advisory board member, or speaker for AbbVie, Baxter, Ferring, Janssen, Celltrion and Emerge Health, and is supported by a NHMRC Emerging Leadership Level 2 Fellowship, and has received research support from AbbVie, Ferring, Janssen and Pfizer. All other authors declare no competing interests., (Crown Copyright © 2024. Published by Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Background and Aims: Crohn's disease strictures are usually treated by a single endoscopic balloon dilation (EBD). We postulated repeat EBD and needle-knife stricturotomy (NKSt), together with inflammation controlled by intense drug therapy, may be more effective., Methods: Twenty-one patients with symptomatic strictures were randomized to a single EBD or intensive treatment with 3 balloon dilations 3 weeks apart and/or NKSt., Results: Of 21 patients, 2 of 5 (40%) undergoing a single EBD and 12 of 16 (72%) undergoing intensive treatment had symptom improvement (odds ratio, 4.49; 95% confidence interval, .54-37.4; P = .164). Eleven patients received >1 EBD without NKSt and 5 underwent ≥1 NKSt. NKSt-treated patients and those with concurrent intensified drug treatment had the best outcomes., Conclusions: Treatment for Crohn's disease strictures with repeat dilations or stricturotomy is feasible and safe and may improve stricture outcomes. Concurrent intensified drug treatment to eliminate inflammation is also associated with improved outcomes. (Clinical trial registration number: NCT03222011.)., Competing Interests: Disclosure The following author disclosed financial relationships: J. D. Schulberg: Speaker for Falk; advisory board for Abbvie. All other authors disclosed no financial relationships. Research support for this study was provided by the Australian National Health and Medical Research Council, Gastroenterological Society of Australia, Ferring IBD Clinician Establishment Award, Australasian Gastro Intestinal Research Foundation, and the Spotlight Foundation., (Copyright © 2024 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Purpose: To compare short-term patient-reported outcomes (PRO) of two contemporary matrix-associated autologous chondrocyte implantation (M-ACI) products for the treatment of large articular cartilage defects of the knee., Methods: A retrospective, registry-based, matched-pair analysis was performed, comparing PRO of patients undergoing isolated M-ACI with either Spherox™, a spheroid-based ACI (Sb-ACI), or NOVOCART™ Inject, a hydrogel-based ACI product (Hb-ACI), for a focal full-thickness cartilage defect of the knee ≥4 cm 2 . Matching parameters included age, sex, body mass index, defect size, defect localization, symptom duration and previous surgeries. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC) score were obtained up to the 24-month follow-up. The total KOOS response rate and percentage of patients attaining a substantial clinical benefit (SCB) in KOOS subscores were calculated., Results: A total of 45 patients per group were matched. The response rate after 24 months was not significantly different between the groups (Sb-ACI 64.4% vs. Hb-ACI 82.2%, p = 0.057). The number of patients with a SCB at 24 months was not significantly different in any KOOS subscore, despite significantly higher improvement of the total KOOS (14.8 ± 16.2 vs. 21.5 ± 15.4, p = 0.047) and KOOS pain in the Hb-ACI group (12.2 ± 18.6 vs. 20.6 ± 19.1, p = 0.037). The IKDC score in the Hb-ACI group was significantly higher at the 12- and 24-month follow-up (60.7 ± 20.2 vs. 70.9 ± 18.0, p = 0.013)., Conclusion: The response rate and number of patients achieving an SCB were not significantly different between patients treated with Sb-ACI or Hb-ACI. Both procedures can achieve favourable 2-year PRO. Hb-ACI was associated with better PRO between 1 and 2 years postoperatively; however, the clinical relevance of this benefit is yet to be proven., Level of Evidence: III, Retrospective comparative study., (© 2024 The Authors. Knee Surgery, Sports Traumatology, Arthroscopy published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Background & Aims: Intestinal ultrasound (IUS) is increasingly used to assess Crohn's disease (CD) activity in clinical practice. However, application in clinical trials has been limited by heterogeneous scoring methods and concerns about reliability. We aimed to determine the inter- and intra-rater reliability of locally and centrally read IUS parameters for evaluating CD using prospectively performed scans., Methods: Twenty-four participants with CD and 6 gastroenterologists participated in a 2-day workshop where each participant underwent 6 IUS scans in total. Eight IUS parameters (bowel wall thickness [BWT], bowel wall stratification [BWS], color Doppler signal [CDS], inflammatory mesenteric fat [i-fat], submucosal prominence, submucosal layer thickness, haustra coli/peristalsis, and affected segment length) and an overall measure of sonographic disease activity were blindly assessed by the 6 local readers and 4 central gastroenterologist-sonographers. Reliability was quantified using intraclass correlation coefficients (ICCs). Institutional review board approval was granted for this study (12938)., Results: Five IUS parameters demonstrated at least moderate (ICC ≥0.41) inter- and intra-rater reliability when local and central reading was performed (BWT, CDS, i-fat, submucosal prominence, and affected segment length). Reliability was generally better with central, in distinction to local, reading. ICCs for BWS and i-fat were highest when evaluated as binary outcomes. Sensitivity analyses demonstrated that IUS parameters are most reliable when evaluated in the worst affected segment. Fair reliability was observed when local readers identified the worst affected segment., Conclusions: Local and central reading of IUS demonstrated at least moderate inter- and intra-rater reliability for several parameters. This study supports refining existing activity indices and incorporating IUS central reading into clinical trials., (Copyright © 2024 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Introduction: A substantial proportion of patients with inflammatory bowel disease (IBD) on intravenous infliximab require dose intensification. Accessing additional intravenous infliximab is labour-intensive and expensive, depending on insurance and pharmaceutical reimbursement. Observational data suggest that subcutaneous infliximab may offer a convenient and safe alternative to maintain disease remission in patients requiring dose-intensified infliximab. A prospective, controlled trial is required to confirm that subcutaneous infliximab is as effective as dose-intensified intravenous infliximab, to identify predictors of disease flare and to establish the role of subcutaneous infliximab therapeutic drug monitoring., Methods and Analysis: The DISCUS-IBD trial is an investigator-initiated, prospective, multicentre, randomised, open-label non-inferiority study comparing the rate of disease flares in participants randomised to continue dose-intensified intravenous infliximab to those switched to subcutaneous infliximab after 48 weeks. Participants are adult patients with IBD in sustained corticosteroid-free remission on any regimen of dose-intensified infliximab up to a maximum of 10 mg/kg 4-weekly intravenously. Participants allocated to intravenous infliximab will continue infliximab at the same dose-intensified regimen they were receiving at study enrolment. Subcutaneous infliximab dosing will be stratified by prior intravenous infliximab dosing. Clinical (Harvey-Bradshaw Index, partial Mayo score), biochemical (C reactive protein, faecal calprotectin), pharmacokinetic (drug-level±antidrug antibodies) and qualitative data are collected 12-weekly until study conclusion at week 48. 13 sites across Australia will participate in recruitment to reach a calculated sample size of 120 participants., Ethics and Dissemination: Multisite ethics approval was obtained from the Health District Human Research Ethics Committee (HREC) at The Alfred Hospital under a National Mutual Acceptance (NMA) agreement (HREC/90559/Alfred-2022; Local Reference: Project 618/22, version 1.6, 2 March 2023). Findings will be reported at national and international gastroenterology meetings and published in peer-reviewed journals. DISCUS-IBD was prospectively registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR) prior to commencing recruitment., Trial Registration Number: ACTRN12622001458729., Competing Interests: Competing interests: RDL has received conference fees from Janssen and Celltrion Healthcare. AS has received speaker fees from Sandoz and received research support and advisory fees from AbbVie, Pfizer, and Arrow Pharmaceuticals. GJW has served as a speaker, a consultant or an advisory board member for Janssen, Galapagos, AbbVie, Ferring, Dr Falk Pharma, Nova Labs and Sandoz. GTM has received educational grants or research support from GESA, The Gutsy Group, NHMRC, MRFF, AbbVie, Janssen, Pfizer, Shire and Takeda; speaker fees from AbbVie, Ferring, Janssen, Orphan, Pfizer, Roche, Sandoz, Shire and Takeda and has serve on advisory boards for AbbVie, Emerge, Eli-Lilly, Gilead, Hospira, Janssen, Orphan, MSD, Pfizer, Shire and Takeda. KL declares speaker fees, advisory Board fees and/or conference travel/registration support from AbbVie, Bristol Myers Squibb, Chiesi, Dr Falk, Ferring, Gilead, Guidepoint, Intercept Pharmaceuticals, Janssen-Cilag, MSD, Norgine, Pfizer, Sandoz, Takeda and the RAH Research Fund. JA has served as a speaker, a consultant and an advisory board member for, and has received research funding from, Abbott, AbbVie, Allergan, Anatara, AstraZeneca, Bayer, Celgene, Falk, Ferring, Gilead, Hospira, Immunic, ImmunsanT, Janssen, MSD, Nestle, Progenity, Pfizer, Sandoz, Shire, Takeda, Vifor, RAH Research Fund, The Hospital Research Fund with all monies received by her department for research support. YKA reports grants from Janssen, during the conduct of the study; has received speaking and consulting fees from AbbVie, Bristol Myers Squibb, Celltrion, Chiesi, Dr Falk, Ferring, Janssen, Pfizer, Sandoz, Shire and Takeda; served on advisory boards for AbbVie, Bristol Myers Squibb, Chiesi, Janssen, NPS Medicine wise, Microba and received research and educational funding from Abbvie, Celltrion, Dr Falk, Janssen, Pfizer, Sandoz and Takeda. RVB has received grant/research support/speaker fees from AbbVie, Ferring, Janssen, Shire, Takeda, Bristol Myer Squibb and Emerge Health; and is a shareholder in Biomebank. SC declares advisory board participation, speaker fees, educational support and/or research support for Liverpool Hospital, South Western Sydney Local Health District (SWSLHD) Academic Unit or Crohn’s Colitis Cure from: AbbVie, Amgen, BMS, Celltrion, Chiesi, Eli-Lilly, Dr Falk, Ferring, Fresenius Kabi, Gilead, GSK, Janssen, MSD, Novartis, Organon, Pfizer, Sandoz, Takeda and non-pharmacological research support from Agency for Clinical Innovation, Gastroenterological Society of Australia, The Leona M and Harry B Helmsley Charitable Trust, Medical Research Future Fund, SWSLHD, Sydney Partnership for Health, Research and Enterprise (SPHERE). MG has served on the advisory board of Pfizer and has received speaker fees, research or travel grants from AbbVie, Celltrion, Dr Falk, Janssen, Pfizer, Pharmacosmos, Takeda. EKW declares speaker and consulting fees from AbbVie, BMS, Celltrion, Falk, Ferring, Janssen, Pfizer and research funding/support from AbbVie, Ferring, Janssen. JPS has received conference fees from Janssen, BMS, Takeda, educational grants from Pfizer, speaker fees from AbbVie, Takeda and Pfizer and an unrestricted grant from Tillots. PDC has served as a consultant, an advisory board member or a speaker for AbbVie, Baxter, Ferring, Janssen, Celltrion, Emerge Health, Shire and Takeda and received research support from Ferring, Shire, Janssen, AbbVie, and Takeda. MGW has received educational grants and speakers fees from AbbVie, Takeda and Ferring; travel grants from Pfizer; and has served on advisory boards for AbbVie. MPS has received educational grants or research support from Ferring, Orphan and Gilead; speakers fees from Janssen, AbbVie, Ferring, Takeda, Pfizer and Shire; and has served on advisory boards for Janssen, Takeda, Pfizer, Celgene, AbbVie, MSD, Emerge Health, Gilead and BMS. JM, PH, RBG, DC, MS, EC, LT, GH and AB declare no relevant competing interests., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

There are wide-ranging probiotic choices in Australasia. We reviewed the efficacy of probiotics for the management of gastrointestinal (GI) conditions in adults and assessed relevance to clinical practice. The benefits of probiotics were inconsistent, with a strong consensus reached for only a few of the indications. As different species/strains and combinations differ in efficacy, results cannot be extrapolated from one to another. This review endorses specific probiotics for limited indications. Efficacy of most marketed probiotic formulations remains unstudied and unproven, warranting further research., (© 2024 Royal Australasian College of Physicians.)

Plant pollen is rich in protein, sterols and lipids, providing crucial nutrition for many pollinators. However, we know very little about the quantity, quality and timing of pollen availability in real landscapes, limiting our ability to improve food supply for pollinators. We quantify the floral longevity and pollen production of a whole plant community for the first time, enabling us to calculate daily pollen availability. We combine these data with floral abundance and nectar measures from UK farmland to quantify pollen and nectar production at the landscape scale throughout the year. Pollen and nectar production were significantly correlated at the floral unit, and landscape level. The species providing the highest quantity of pollen on farmland were Salix spp. (38%), Filipendula ulmaria (14%), Rubus fruticosus (10%) and Taraxacum officinale (9%). Hedgerows were the most pollen-rich habitats, but permanent pasture provided the majority of pollen at the landscape scale, because of its large area. Pollen and nectar were closely associated in their phenology, with both peaking in late April, before declining steeply in June and remaining low throughout the year. Our data provide a starting point for including pollen in floral resource assessments and ensuring the nutritional requirements of pollinators are met in farmland landscapes., (© 2024 The Authors New Phytologist © 2024 New Phytologist Foundation.)

Background & Aims: Vedolizumab and ustekinumab pharmacokinetics in pregnancy and the infant after in utero exposure remain incompletely defined. We aim to define the antenatal stability of ustekinumab and vedolizumab levels and the time at which infant drug levels become undetectable., Methods: This multicenter prospective observational cohort study recruited pregnant or preconception women with inflammatory bowel disease receiving vedolizumab or ustekinumab. Trough drug levels, clinical data, and biochemical data were documented preconception, during each trimester of pregnancy, and postpartum. Maternal and cord blood drug levels were measured at delivery and in infants until undetectable. Infant outcomes were assessed until 2 years of age., Results: A total of 102 participants (vedolizumab, n = 58) were included. The majority of mothers were, and remained, in clinical and biochemical remission. Maternal vedolizumab levels decreased over the course of pregnancy in association with increasing weight, rather than increasing gestation. Maternal ustekinumab levels remained stable. The median time to drug becoming undetectable in the infant was shorter for vedolizumab (11 wk; range, 5-19 wk; n = 32) than ustekinumab (14 wk; range, 9-36 wk; n = 17) and correlated positively with infant delivery level. Thirty-two of 41 (88%) and 17 of 30 (67%) vedolizumab- and ustekinumab-exposed infants had undetectable drug levels by 15 weeks of age, respectively. Pregnancy and infant outcomes were favorable. Twenty infants with undetectable drug levels received the rotavirus vaccine, with no adverse reactions reported., Conclusions: Maternal vedolizumab levels decreased, whereas ustekinumab levels remained stable over the course of pregnancy. Most vedolizumab- and approximately half of ustekinumab-exposed infants had undetectable drug levels by 15 weeks of age. No concerning maternal or infant safety signals were identified., (Copyright © 2024 AGA Institute. All rights reserved.)

Purpose: Cross-sectional imaging facilitates the assessment of transmural healing in patients with Crohn's disease. This systematic review addresses the utility of MRI and intestinal ultrasound (IUS) in the assessment of disease activity in response to drug therapy compared with endoscopy in patients with luminal Crohn's disease., Methods: Database searches were undertaken using predefined terms. Studies with ≥10 patients with luminal Crohn's disease with paired endoscopy and imaging (MRI or IUS) after treatment initiation were included. Publications were identified through searches of six bibliographic databases, all run on June 24, 2022. Records were screened on title and abstract, then full text, by two independent reviewers., Results: In total, 5,760 records were identified, with 24 studies meeting the inclusion criteria. Ten studies examined IUS and found good correlation between IUS and endoscopic remission (κ = 0.63-0.73). Early reduction in bowel wall thickness at 4 to 8 weeks predicted endoscopic response at 12 to 38 weeks (area under the receiver operating characteristic curve [AUROC], 0.77; odds ratio, 10.8; P = .01). Twelve studies examined MRI, with the Magnetic Resonance Index of Activity score having high accuracy for predicting endoscopic remission (AUROC, 0.97; sensitivity, 93%; specificity, 77%). A Simplified Magnetic Resonance Index of Activity score cutoff of ≥1 identifies active endoscopic disease (AUROC, 0.92; 95% confidence interval, 0.88-0.95; P < .0001)., Conclusions: IUS and MRI are both reliable, noninvasive modalities for assessing transmural healing in patients with Crohn's disease and are accurate in monitoring the response to drug therapy. These modalities can be used to monitor response to biologic induction therapy, with early changes predictive of response to treatment., (Copyright © 2023 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Objective: We postulated that adalimumab [ADA] drug clearance [CL] may be a more critical determinant of therapeutic outcome than ADA concentration. This was tested in Crohn's disease [CD] patients undergoing ADA maintenance treatment., Methods: CD patients from four cohorts received ADA induction and started maintenance therapy. Therapeutic outcomes consisted of endoscopic remission [ER], sustained C-reactive protein [CRP] based clinical remission [defined as CRP levels below 3 mg/L in the absence of symptoms], and faecal calprotectin [FC] level below 100 µg/g. Serum albumin, ADA concentration, and anti-drug antibody status were determined using immunochemistry and homogeneous mobility shift assay, respectively. CL was determined using a nonlinear mixed effect model with Bayesian priors. Statistical analysis consisted of Mann-Whitney test and logistic regression with calculation of odds ratio. Repeated event analysis was conducted using a nonlinear mixed effect model., Results: In 237 enrolled patients [median age 40 years, 45% females], median CL was lower in patients achieving ER as compared with those with persistent active endoscopic disease [median 0.247 L/day vs 0.326 L/day, respectively] [p <0.01]. There was no significant difference in ADA concentration between patients in endoscopic remission compared with those with recurrence [median 9.3 µg/mL vs 11.7 µg/mL, respectively]. Sustained CRP-based clinical remission and FC levels below 100 µg/g were generally associated with lower CL and higher ADA concentration. Repeated event analysis confirmed those findings with better performances of CL than concentration in associating with ER and other outcomes., Conclusion: Lower ADA clearance is associated with an improved clinical outcome for patients with Crohn's disease and may be a superior pharmacokinetic measure than concentration., (© The Author(s) 2023. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Introduction: We evaluated baseline Clearance of anti-tumor necrosis factors and human leukocyte antigen variant (HLA DQA1*05) in combination as poor prognostic factors (PPF) of pharmacokinetic (PK) origin impacting immune response (formation of antidrug antibodies) and disease control of inflammatory bowel disease (IBD) patients treated with infliximab or adalimumab., Methods: Baseline Clearance was estimated in IBD patients before starting treatment using weight and serum albumin concentrations. HLA DQA1*05 carrier status (rs2097432 A/G or G/G variant) was measured using real time polymerase chain reaction. The outcomes consisted of immune response, clinical and biochemical remission (C-reactive protein<3 mg/L in the absence of symptoms), and endoscopic remission (SES-CD<3). Statistical analysis consisted of logistic regression and nonlinear mixed effect models., Results and Discussion: In 415 patients enrolled from 4 different cohorts (median age 27 [IQR: 15-43] years, 46% females), Clearance>0.326 L/day and HLA DQA1*05 carrier status were 2-fold more likely to have antidrug antibodies (OR=2.3, 95%CI: 1.7-3.4; p<0.001, and OR=1.9, 95%CI: 1.4-2.8; p<0.001, respectively). Overall, each incremental PPF of PK origin resulted in a 2-fold (OR=2.16, 95%CI: 1.7-2.7; p<0.11) [corrected] higher likelihood of antidrug antibody formation. The presence of both PPF of PK origin resulted in higher rates of antidrug antibodies (p<0.01) and lower clinical and biochemical remission (p<0.01). Each incremental increase in PPF of PK origin associated with lower likelihood of endoscopic remission (OR=0.4, 95%CI: 0.2-0.7; p<0.001). Prior biologic experience heightened the negative impact of PPF of PK origin on clinical and biochemical remission (p<0.01). Implementation of proactive therapeutic drug monitoring reduced it, particularly during maintenance and in the presence of higher drug concentrations (p<0.001). We conclude that PPF of PK origin, including both higher Clearance and carriage of HLA DQA1*05, impact outcomes in patients with IBD., Competing Interests: JG has served as speaker, consultant, and advisory member for or has received research funding from MSD, Abbvie, Pfizer, Kern Pharma, Biogen, Mylan, Takeda, Janssen, Roche, Sandoz, Celgene/Bristol Myers, Gilead/Galapagos, Lilly, Ferring, Faes Farma, Shire Pharmaceuticals, Dr. Falk Pharma, Tillotts Pharma, Chiesi, Casen Fleet, Gebro Pharma, Otsuka Pharmaceutical, Norgine and Vifor Pharma. MD is a consultant for Prometheus Laboratories, Janssen, Abbvie, Takeda, Celgene, Gilead, U.C.B., Pfizer, Arena, and Eli Lilly as well as co-Founder of Mi Test Health and Trellus Health. TD is employee of Prometheus Laboratories; MK, AH, and EW: research grants from Prometheus Laboratories; DM: consultant Prometheus Laboratories, Merck; Palatin Bio; Takeda; Prometheus Biosciences; Palisade Bio.s. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Spencer, Dubinsky, Kamm, Chaparro, Gionchetti, Rizzello, Gisbert, Wright, Schulberg, Hamilton, McGovern and Dervieux.)