Vedolizumab and Ustekinumab Levels in Pregnant Women With Inflammatory Bowel Disease and Infants Exposed In Utero.

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.

Reliability of intestinal ultrasound for evaluating Crohn's disease activity using point-of-care and central reading.

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.

Probiotics: are they beneficial?

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.

Hydrogel-based and spheroid-based autologous chondrocyte implantation of the knee show similar 2-year functional outcomes: An analysis based on the German Cartilage Registry (KnorpelRegister DGOU).

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 cm2. 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.

Fecal microbiota transplantation therapy in Crohn's disease: Systematic review.

BACKGROUND: The gastrointestinal microbiota is the key antigenic drive in the inflammatory bowel diseases. Randomized controlled trials (RCTs) in ulcerative colitis have established fecal microbiota transplantation (FMT) as an effective therapy. We have conducted a systematic review to evaluate the efficacy of FMT in Crohn's disease. METHODS: A systematic literature search was performed through to August 2020 (MEDLINE; Embase). Studies were included if they reported FMT administration in patients with Crohn's disease, and reported on clinical outcomes. RESULTS: Fifteen studies published between 2014 and 2020, comprising 13 cohort studies and two RCTs, were included in the analysis. The majority of trials evaluated FMT for induction of remission, with follow-up duration varying from 4 to 52 weeks. One RCT in 21 patients, of single-dose FMT versus placebo, following steroid-induced remission, showed a higher rate of steroid-free clinical remission in the FMT group compared to the control group: 87.5% vs 44.4% at week 10 (P = 0.23). Another RCT, two-dose FMT in 31 patients, showed an overall clinical remission rate of 36% at week 8, however, with no difference in clinical or endoscopic endpoints between FMT administered by gastroscopy and colonoscopy. Considering all studies, the clinical response rates in early follow up were higher following multiple FMT than with single FMT. FMT dose did not appear to influence clinical outcomes, nor did whether FMT was fresh or frozen. FMT delivered via upper gastrointestinal route demonstrated higher early efficacy rates of 75 to 100% compared with lower delivery route rates of 30% to 58%, but on follow up beyond 8 weeks, this difference was not maintained. Whether pre-FMT antibiotic administration was beneficial was not able to be determined due to the limited number of patients receiving antibiotics and varying antibiotic regimens. No serious adverse events were reported. CONCLUSIONS: Preliminary studies suggest that FMT may be an effective therapy in Crohn's disease. However large controlled trials are needed. No serious safety concerns have been identified.

Efficacy of drug and endoscopic treatment of Crohn's disease strictures: A systematic review.

BACKGROUND AND AIMS: Strictures are the commonest complication in Crohn's disease. Surgery and endoscopic dilation are the mainstays of treatment, while drug therapy has often been considered contraindicated. The benefit of nonsurgical treatments, particularly drug and endoscopic therapy, need to be defined. METHODS: Ovid MEDLINE, Embase, Emcare, PsycINFO, CINAHL and the Cochrane Library (inception until August 30, 2019) were searched. Studies with ≥ 10 patients with Crohn's disease strictures, reporting on outcomes following medication or endoscopic treatment, were included. RESULTS: Of 3480 records, 85 studies met inclusion criteria and formed the basis of this analysis. Twenty-five studies assessed drug therapy; none were randomized trials. Despite study heterogeneity anti-tumor necrosis factor (TNF) therapy appeared effective, with 50% of patients avoiding surgery after 4 years of follow up. No other drug therapy was of demonstrable benefit. Sixty studies assessed endoscopic therapy including 56 on endoscopic balloon dilation, two assessed needle knife stricturotomy, and two stent insertion. Dilation was equally effective for de novo and anastomotic strictures ≤ 5 cm in length, with most studies reporting a subsequent surgical rate of 30% to 50%. Repeat dilation was required in approximately half of all patients. CONCLUSIONS: Anti-TNF drug therapy and endoscopic balloon dilation are effective strategies for avoiding surgery in patients with stricturing Crohn's disease. Additional endoscopic therapies require further evaluation. Early data suggest that combining these therapies may provide greater benefit than individual therapies. Optimization of current drug and endoscopic therapy, and the incorporation of newer therapies, are needed for stricturing Crohn's disease.

The gut microbiota and gut disease.

The gut microbiota has a key role in the maintenance of good health, and in the pathogenesis of gastrointestinal diseases. These conditions include the inflammatory bowel diseases, colorectal cancer, coeliac disease and metabolic liver disease. Although the nature of the microbial disturbance in these conditions has not been fully characterised, this has not prevented the development of microbially based therapies. Microbial-changing therapies may address newly recognised pathophysiological contributors of disease and have the potential to replace or supplement standard therapies. Antibiotics play a role in initial Clostridiodes difficile disease and some specific inflammatory disorders. Probiotics have a more limited proven role. Faecal microbiota transplantation is of proven therapeutic benefit in recurrent C. difficile disease and ulcerative colitis. We review the current literature for microbiota-targeted therapies in gut disorders.

Magnetic resonance enterography for predicting the clinical course of Crohn's disease strictures.

BACKGROUND AND AIMS: Strictures are the most common Crohn's disease complication, but their natural history is unknown. This study aimed to characterize inflammation, predict prognosis, and understand the impact of drug therapy using magnetic resonance enterography (MRE). METHODS: Patients with a stricture diagnosed on MRE over a 5-year period were reviewed for MRE disease extent and inflammation, clinical course, C-reactive protein, response to anti-TNF therapy, endoscopic dilatation, hospitalization, and surgery. RESULTS: 136 patients had 235 strictures (77, one and 59, ≥ 2 strictures). TREATMENT: 46% of patients underwent surgery after a median 6 months; median follow-up for those not requiring surgery was 41 months. Predictors of surgery: Hospitalization because of obstruction predicted subsequent surgery (OR 2.50; 95% CI 1.06-5.90) while anti-TNF therapy commenced at stricture diagnosis was associated with a reduced risk (OR 0.23; 95% CI 0.05-0.99). MRE characteristics associated with surgery were proximal bowel dilatation ≥ 30-mm diameter (OR 2.98; 95% CI 1.36-6.55), stricture bowel wall thickness ≥ 10-mm (OR 2.42; 95% CI 1.11-5.27), and stricture length > 5-cm (OR 2.56; 95% CI 1.21-5.43). 81% of patients with these three adverse MRE features required surgery versus 17% if none were present (P < 0.001). Accuracy for these three MRE variables predicting surgery was high (AUC 0.76). CONCLUSION: Magnetic resonance enterography findings in Crohn's disease strictures are highly predictive of the disease course and the need for future surgery. MRE may also identify who would benefit from treatment intensification. Anti-TNF therapy is associated with reduced risk of surgery and appears to alter the natural history of this complication.

Management of inflammatory bowel disease.

Australia has one of the highest incidence rates of inflammatory bowel disease (IBD) in the world. Early diagnosis and treatment for IBD is critical. For Crohn disease, in particular, this may change the natural history of disease and reduce disability. Faecal calprotectin is a sensitive test that can be used by primary care physicians to assist in determining which patients with gastrointestinal symptoms may have IBD. This allows for prompt identification of patients who may benefit from endoscopy. Regular re-evaluation of disease status with strategies that can safely, readily and reliably detect the presence of inflammation with faecal biomarkers and imaging is important. To avoid the risks of cumulative radiation exposure, magnetic resonance imaging and/or intestinal ultrasound, rather than computed tomography scanning, should be performed when possible. Drug treatments for IBD now include five biological drugs listed by the Pharmaceutical Benefits Scheme: adalimumab, infliximab, golimumab, vedolizumab and ustekinumab. Such developments offer the possibility for improved disease control in selected patients.

Serologic antibodies in relation to outcome in postoperative Crohn's disease.

BACKGROUND AND AIM: Disease recurs frequently after Crohn's disease resection. The role of serological antimicrobial antibodies in predicting recurrence or as a marker of recurrence has not been well defined. METHODS: A total of 169 patients (523 samples) were prospectively studied, with testing peri-operatively, and 6, 12 and 18 months postoperatively. Colonoscopy was performed at 18 months postoperatively. Serologic antibody presence (perinuclear anti-neutrophil cytoplasmic antibody [pANCA], anti-Saccharomyces cerevisiae antibodies [ASCA] IgA/IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2, anti-Fla-X) and titer were tested. Quartile sum score (range 6-24), logistic regression analysis, and correlation with phenotype, smoking status, and endoscopic outcome were assessed. RESULTS: Patients with ≥ 2 previous resections were more likely to be anti-OmpC positive (94% vs 55%, ≥ 2 vs < 2, P = 0.001). Recurrence at 18 months was associated with anti-Fla-X positivity at baseline (49% vs 29%; positive vs negative, P = 0.033) and 12 months (52% vs 31%, P = 0.04). Patients positive (n = 28) for all four antibacterial antibodies (anti-CBir1, anti-OmpC, anti-A4-Fla2, and anti-Fla-X) at baseline were more likely to experience recurrence at 18 months than patients negative (n = 32) for all four antibodies (82% vs 18%, P = 0.034; odds ratio 6.4, 95% confidence interval 1.16-34.9). The baseline quartile sum score for all six antimicrobial antibodies was higher in patients with severe recurrence (Rutgeert's i3-i4) at 18 months, adjusted for clinical risk factors (odds ratio 1.16, 95% confidence interval 1.01-1.34, P = 0.039). Smoking affected antibody status. CONCLUSIONS: Anti-Fla-X and presence of all anti-bacterial antibodies identifies patients at higher risk of early postoperative Crohn's disease recurrence. Serologic screening pre-operatively may help identify patients at increased risk of recurrence.

Measurement of fecal calprotectin improves monitoring and detection of recurrence of Crohn's disease after surgery.

BACKGROUND & AIMS: Crohn's disease (CD) usually recurs after intestinal resection; postoperative endoscopic monitoring and tailored treatment can reduce the chance of recurrence. We investigated whether monitoring levels of fecal calprotectin (FC) can substitute for endoscopic analysis of the mucosa. METHODS: We analyzed data collected from 135 participants in a prospective, randomized, controlled trial, performed at 17 hospitals in Australia and 1 hospital in New Zealand, that assessed the ability of endoscopic evaluations and step-up treatment to prevent CD recurrence after surgery. Levels of FC, serum levels of C-reactive protein (CRP), and Crohn's disease activity index (CDAI) scores were measured before surgery and then at 6, 12, and 18 months after resection of all macroscopic Crohn's disease. Ileocolonoscopies were performed at 6 months after surgery in 90 patients and at 18 months after surgery in all patients. RESULTS: Levels of FC were measured in 319 samples from 135 patients. The median FC level decreased from 1347 µg/g before surgery to 166 µg/g at 6 months after surgery, but was higher in patients with disease recurrence (based on endoscopic analysis; Rutgeerts score, ≥i2) than in patients in remission (275 vs 72 µg/g, respectively; P < .001). Combined 6- and 18-month levels of FC correlated with the presence (r = 0.42; P < .001) and severity (r = 0.44; P < .001) of CD recurrence, but the CRP level and CDAI score did not. Levels of FC greater than 100 µg/g indicated endoscopic recurrence with 89% sensitivity and 58% specificity, and a negative predictive value (NPV) of 91%; this means that colonoscopy could have been avoided in 47% of patients. Six months after surgery, FC levels less than 51 µg/g in patients in endoscopic remission predicted maintenance of remission (NPV, 79%). In patients with endoscopic recurrence at 6 months who stepped-up treatment, FC levels decreased from 324 µg/g at 6 months to 180 µg/g at 12 months and 109 µg/g at 18 months. CONCLUSIONS: In this analysis of data from a prospective clinical trial, FC measurement has sufficient sensitivity and NPV values to monitor for CD recurrence after intestinal resection. Its predictive value might be used to identify patients most likely to relapse. After treatment for recurrence, the FC level can be used to monitor response to treatment. It predicts which patients will have disease recurrence with greater accuracy than CRP level or CDAI score.

Calprotectin or Lactoferrin: Do They Help.

BACKGROUND: The diagnosis and monitoring of inflammatory bowel disease (IBD) has traditionally relied on clinical assessment, serum markers of inflammation and endoscopic examination. Fecal biomarkers such as calprotectin (FC) and lactoferrin (FL) are predominantly derived from neutrophils, are easily detectable in the feces and are now established as valuable markers of intestinal inflammation. In recent years, a 'treat to target' concept has emerged for the management of IBD. Adequate control of inflammation in IBD at a biochemical level is quickly becoming an important target in IBD management. KEY MESSAGES: Fecal biomarkers have been shown to be significantly and consistently increased in both adult and pediatric patients with IBD versus those without IBD. Fecal biomarkers are therefore useful in determining those patients with gastrointestinal symptoms who are likely to benefit from colonoscopy versus those in whom colonoscopy is likely to be normal. Fecal biomarkers correlate significantly with endoscopic disease in both Crohn's disease and ulcerative colitis. Suggested cutoffs for FC for endoscopically active disease in IBD range from 50 to 280 µg/g. Fecal biomarkers reflect the success of treatment intensification and can help predict clinical relapse. Both FC and FL are accurate in the detection of postoperative endoscopic recurrence of Crohn's disease, and FC may be clinically useful in predicting those patients with acute severe ulcerative colitis who may progress to colectomy. There are limitations to these fecal tests including a false positive rate and intra-individual variability. CONCLUSIONS: This review focuses on the role of fecal biomarkers in the diagnosis, monitoring and management of IBD and how best to interpret results. We will discuss the emerging role of these biomarkers in the IBD management landscape including FC-guided drug dosing and the development of home-based testing and e-health applications. Fecal biomarker results must always be interpreted in a clinical context. Endoscopic assessment remains the gold standard for diagnosis and monitoring of IBD.

Vancomycin and Ustekinumab Combination Therapy in Acute Ulcerative Colitis.

The role of antibiotics in the treatment of ulcerative colitis is limited. We present a case of a 25-year-old woman who presented with a flare of ulcerative colitis after an episode of infectious gastroenteritis on a background of known primary sclerosing cholangitis. After the flare, she experienced persistent abdominal pain and diarrhea associated with elevated fecal calprotectin and deep rectosigmoid ulcerations on endoscopy. After unsuccessful trials of vedolizumab, infliximab, and tofacitinib, the patient was commenced on ustekinumab, tacrolimus, and oral vancomycin. Tacrolimus was ceased successfully, but while on maintenance ustekinumab therapy, 2 attempts to cease vancomycin resulted in symptom recurrence and rising fecal calprotectin that improved with vancomycin recommencement. To date, the patient has been on vancomycin continuously for 18 months and remains clinically well with colonoscopy demonstrating inactive colitis. This case highlights how vancomycin may be beneficial in the management of treatment-refractory ulcerative colitis as an adjunct to biologic therapy.

Intestinal Ultrasound and MRI for Monitoring Therapeutic Response in Luminal Crohn's Disease: A Systematic Review.

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.

Adalimumab Clearance, Rather Than Trough Level, May Have Greatest Relevance to Crohn's Disease Therapeutic Outcomes Assessed Clinically and Endoscopically.

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.

Corrigendum: Poor prognostic factors of pharmacokinetic origin predict outcomes in inflammatory bowel disease patients treated with anti-tumor necrosis factor-α.

[This corrects the article DOI: 10.3389/fimmu.2024.1342477.].

Poor prognostic factors of pharmacokinetic origin predict outcomes in inflammatory bowel disease patients treated with anti-tumor necrosis factor-α.

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.

Switching from Dose-Intensified intravenous to SubCutaneoUS infliximab in Inflammatory Bowel Disease (DISCUS-IBD): protocol for a multicentre randomised controlled trial.

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.

Intensified versus standard dose infliximab induction therapy for steroid-refractory acute severe ulcerative colitis (PREDICT-UC): an open-label, multicentre, randomised controlled trial.

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.