Review article: applying pharmacokinetics to optimise dosing of anti-TNF biologics in acute severe ulcerative colitis

C-reactive Protein: An Inflammatory Biomarker and a Predictor of Neurodegenerative Disease in Patients With Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) refers to two chronic conditions of the digestive tract: ulcerative colitis (UC) and Crohn's disease (CD), representing a progressive inflammatory process that mainly occurs in the gut, with frequent extra-intestinal manifestations. Even if remission is periodically obtained for some patients, the histological activity and digestive symptoms may continue, maintaining a persistent systemic inflammation that could induce further extra-intestinal complications and contribute to the development of neurodegenerative disease. C-reactive protein (CRP) is an acute-phase reactant that is widely accepted as a dominant serum biomarker in IBD. CRP consequently activates the complement cascade, supports the release of pro-inflammatory cytokines, and the clearance of microbial pathogens. All these processes facilitate further processes, including atherosclerosis and hypercoagulability, alteration of the intestinal microbiota, and the increased permeability of the intestinal barrier for neurotoxic substances produced by gut microorganisms, due to the presence of a high level of lipopolysaccharides. For IBD, the connection between intestinal inflammation and central nervous system inflammation could be explained through the activity of the vagus nerve, a carrier of cytokines, CRP, and toxic materials to the brain, potentially inducing vascular lesions and damage of the glial vascular unit, with further risk for degeneration within the central nervous system. CRP is a key marker for IBD pathogenesis and is able to dissociate into its monomeric form, mCRP, on contact with activated cell and tissue components via the systemic circulation. We hypothesize that the chronic inflammatory process within IBD could initiate neuroinflammation and neurodegeneration, and therefore, further investigation of the significance of chronically raised plasma of CRP and mCRP in patients with IBD is warranted, as it may represent a critical predictive factor associated with a later neurodegenerative risk. Any future initiative aimed at pharmacologic modulation of CRP (e.g., blocking CRP-mCRP dissociation), could represent a new therapeutic approach protecting against intestinal inflammation and concomitantly reducing the risk of neuroinflammation, neurodegeneration, and cognitive decline.

Predictive biomarkers for anti-TNF alpha therapy in IBD patients

Inflammatory bowel disease (IBD) is a chronic gastrointestinal condition characterized by severe gut inflammation, commonly presenting as Crohn's disease, ulcerative colitis or categorized as IBD- unclassified. While various treatments have demonstrated efficacy in adult IBD patients, the advent of anti-TNF therapies has significantly revolutionized treatment outcomes and clinical management. These therapies have played a pivotal role in achieving clinical and endoscopic remission, promoting mucosal healing, averting disease progression, and diminishing the necessity for surgery. Nevertheless, not all patients exhibit positive responses to these therapies, and some may experience a loss of responsiveness over time. This review aims to present a comprehensive examination of predictive biomarkers for monitoring the therapeutic response to anti-TNF therapy in IBD patients. It will explore their limitations and clinical utilities, paving the way for a more personalized and effective therapeutic approach.

A personalized network framework reveals predictive axis of anti-TNF response across diseases

Personalized treatment of complex diseases has been mostly predicated on biomarker identification of one drug-disease combination at a time. Here, we use a computational approach termed Disruption Networks to generate a data type, contextualized by cell-centered individual-level networks, that captures biology otherwise overlooked when performing standard statistics. This data type extends beyond the "feature level space", to the "relations space", by quantifying individual-level breaking or rewiring of cross-feature relations. Applying Disruption Networks to dissect high-dimensional blood data, we discover and validate that the RAC1-PAK1 axis is predictive of anti-TNF response in inflammatory bowel disease. Intermediate monocytes, which correlate with the inflammatory state, play a key role in the RAC1-PAK1 responses, supporting their modulation as a therapeutic target. This axis also predicts response in rheumatoid arthritis, validated in three public cohorts. Our findings support blood-based drug response diagnostics across immune-mediated diseases, implicating common mechanisms of non-response.

In-hospital management of inflammatory bowel disease

PURPOSE OF REVIEW

The management of hospitalized patients with inflammatory bowel disease (IBD) is complex. Despite considerable therapeutic advancements in outpatient ulcerative colitis and Crohn's disease management, the in-hospital management continues to lag with suboptimal outcomes. The purpose of this review is to provide a brief overview of our approach to managing patients hospitalized with acute severe ulcerative colitis (ASUC) and Crohn's disease-related complications, followed by a summary of emerging evidence for new management approaches.

RECENT FINDINGS

ASUC has seen the emergence of well validated prognostic models for colectomy as well as the development of novel treatment strategies such as accelerated infliximab dosing, Janus kinase inhibitor therapy, and sequential therapy, yet the rate of colectomy for steroid-refractory ASUC has not meaningfully improved. Crohn's disease has seen the development of better diagnostic tools, early Crohn's disease-related complication stratification and identification, as well as better surgical techniques, yet the rates of hospitalization and development of Crohn's disease-related complications remain high.

SUMMARY

Significant progress has been made in the in-hospital IBD management; however, both the management of ASUC and hospitalized Crohn's disease remain a challenge with suboptimal outcomes. Critical knowledge gaps still exist, and dedicated studies in hospitalized patients with IBD are needed to address them.

Therapeutic Drug Monitoring of Infliximab in Acute Severe Ulcerative Colitis

Therapeutic drug monitoring (TDM) is a useful strategy in ulcerative colitis (UC). Nearly a quarter of UC patients will experience acute severe UC (ASUC) in their lifetime, including 30% who will fail first-line corticosteroid therapy. Steroid-refractory ASUC patients require salvage therapy with infliximab, cyclosporine, or colectomy. Fewer data are available for the use of TDM of infliximab in ASUC. The pharmacokinetics of ASUC make TDM in this population more complex. High inflammatory burden is associated with increased infliximab clearance, which is associated with lower infliximab drug concentrations. Observational data support the association between increased serum infliximab concentrations, lower clearance, and favorable clinical and endoscopic outcomes, as well as decreased rates of colectomy. Data regarding the benefit of accelerated or intensified dosing strategies of infliximab-as well as target drug concentration thresholds-in ASUC patients remain more equivocal, though limited by their observational nature. Studies are underway to further evaluate optimal dosing and TDM targets in this population. This review examines the evidence for TDM in patients with ASUC, with a focus on infliximab.

Multicenter Cohort Study of Infliximab Pharmacokinetics and Therapy Response in Pediatric Acute Severe Ulcerative Colitis

BACKGROUND & AIMS

We aimed to model infliximab (IFX) pharmacokinetics (PK) in pediatric acute severe ulcerative colitis (ASUC) and assess the association between PK parameters, including drug exposure, and clinical response.

METHODS

We studied a multicenter prospective cohort of hospitalized children initiating IFX for ASUC or IBD-unclassified. Serial IFX serum concentrations over 26 weeks were used to develop a PK model. We tested the association of PK parameter estimates with day 7 clinical response, week 8 clinical remission, week 26 corticosteroid-free clinical remission (CSF-CR) (using the Pediatric Ulcerative Colitis Activity Index), and colectomy-free survival.

RESULTS

Thirty-eight participants received IFX (median initial dose, 9.9 mg/kg). Day 7 clinical response, week 8 clinical remission, and week 26 CSF-CR occurred in 71%, 55%, and 43%, respectively. Albumin, C-reactive protein, white blood cell count, platelets, weight, and antibodies to IFX were significant covariates incorporated into a PK model. Week 26 non-remitters exhibited faster IFX clearance than remitters (P = .013). However, cumulative IFX exposure did not differ between clinical response groups. One (2.7%) and 4 (10.8%) participants underwent colectomy by week 26 and 2 years, respectively. Day 3 IFX clearance >0.02 L/h was associated with colectomy (hazard ratio, 58.2; 95% confidence interval, 6.0-568.6; P < .001).

CONCLUSIONS

At median higher-than-label IFX dosing for pediatric ASUC, baseline faster IFX CL was associated with colectomy and at week 26 with lack of CSF-CR. IFX exposure was not predictive of clinical outcomes. Higher IFX dosing may sufficiently optimize early outcomes in pediatric ASUC. Larger studies are warranted to determine whether sustained intensification can overcome rapid clearance and improve later outcomes.

CLINICALTRIALS

gov identifier: NCT02799615.

Real world population pharmacokinetic study in children and young adults with inflammatory bowel disease discovers novel blood and stool microbial predictors of vedolizumab clearance

BACKGROUND

Vedolizumab for inflammatory bowel disease (IBD) is often intensified based on distinct pharmacokinetics in children. Prior adult-specific population pharmacokinetic models have identified limited covariates of drug clearance.

AIMS

To establish a population pharmacokinetic model for children and young adults to identify novel covariates of drug clearance to better account for paediatric-specific inter-patient variability in vedolizumab pharmacokinetics; a key secondary exploratory aim was to identify microbial signatures of pharmacokinetic outcomes in a subset of patients.

METHODS

The study included data from 463 observed vedolizumab concentrations (59 peaks and 404 troughs) from 74 patients with IBD (52 with Crohn's disease and 22 with ulcerative colitis or unclassified IBD, median age 16 years). Pharmacokinetic analysis was conducted with non-linear mixed effects modelling. For the evaluation of the exposure-response relationship, clinical outcomes were evaluated by trough levels, clearance and vedolizumab exposure. Whole-genome metagenomic sequencing was conducted at baseline and week 2.

RESULTS

A two-compartment population pharmacokinetic model was identified with a clear correlation between CL and weight, erythrocyte sedimentation rate, and hypoalbuminemia. Trough concentrations before infusion 3 (37 μg/ml) and before infusion 4 (20 μg/ml) best predicted steroid-free clinical remission at infusion 4. Using faecal metagenomics, we identified an early (baseline and week 2) abundance of butyrate-producing species and pathways that were associated with an infusion 4 trough concentration >20 μg/ml.

CONCLUSIONS

This novel paediatric vedolizumab pharmacokinetic model could inform precision dosing. While additional studies are needed, an abundance of faecal butyrate producers is associated with early response to vedolizumab, suggesting that microbial analysis may be beneficial to biological selection.

Inhibition of tumor necrosis factor receptor 1 and the risk of periodontitis

Aim

To investigate the effect of genetically proxied inhibition of tumor necrosis factor receptor 1 (TNFR1) on the risk of periodontitis.

Materials and methods

Genetic instruments were selected from the vicinity of TNFR superfamily member 1A (TNFRSF1A) gene (chromosome 12; base pairs 6,437,923-6,451,280 as per GRCh37 assembly) based on their association with C-reactive protein (N= 575,531). Summary statistics of these variants were obtained from a genome-wide association study (GWAS) of 17,353 periodontitis cases and 28,210 controls to estimate the effect of TNFR1 inhibition on periodontitis using a fixed-effects inverse method.

Results

Considering rs1800693 as an instrument, we found no effect of TNFR1 inhibition on periodontitis risk (Odds ratio (OR) scaled per standard deviation increment in CRP: 1.57, 95% confidence interval (CI): 0.38;6.46). Similar results were derived from a secondary analysis that used three variants (rs767455, rs4149570, and rs4149577) to index TNFR1 inhibition.

Conclusions

We found no evidence of a potential efficacy of TNFR1 inhibition on periodontitis risk.

Colonic Dilatation Complicating Acute Severe Ulcerative Colitis Managed Successfully with Accelerated Infliximab Dosing

Lately, emerging data suggest an association between the development of inflammatory bowel disease and anti-interleukin-17 therapy. Megacolon is a life-threatening complication of acute severe ulcerative colitis (ASUC), but its treatment has not yet been established in current practice guidelines. We report a rare case of known psoriasis treated by secukinumab in a patient who presented with ASUC and colonic dilatation. Neither steroids nor standard infliximab regimen was effective. Finally, rescue therapy with accelerated infliximab strategy resulted in excellent recovery. In certain cases of steroid-refractory ASUC complicated by megacolon, accelerated infliximab regimen can be an alternative to surgery.

Acute Severe Ulcerative Colitis: Optimal Strategies for Drug Therapy

Acute severe ulcerative colitis (ASUC) is a life-threatening medical emergency with considerable morbidity (30% to 40%). Patients with ASUC require hospitalization for prompt medical treatment, and colectomy is considered if medical therapy fails. Corticosteroids remain the primary initial therapy, although one-third of patients do not respond to treatment. Clinical data have indicated that cyclosporine, tacrolimus, and infliximab can be used to treat patients with ASUC who do not respond to intravenous corticosteroids. The effectiveness and safety of sequential therapy have recently been reported; however, the data are not convincing. Importantly, timely decision-making with rescue therapy or surgical treatment is critical to manage ASUC without compromising the health or safety of the patients. In addition, risk stratification and the use of predictive clinical parameters have improved the clinical outcome.of ASUC. Multidisciplinary teams that include inflammatory bowel disease experts, colorectal surgeons, and other medical staff contribute to the better management of patients with ASUC. In this review, we introduce current evidence and present a clinical approach to manage ASUC.

Precision medicine and drug optimization in adult inflammatory bowel disease patients

Inflammatory bowel diseases (IBD) encompass two main entities including ulcerative colitis and Crohn's disease. Although having a common global pathophysiological mechanism, IBD patients are characterized by a significant interindividual heterogeneity and may differ by their disease type, disease locations, disease behaviours, disease manifestations, disease course as well as treatment needs. Indeed, although the therapeutic armamentarium for these diseases has expanded rapidly in recent years, a proportion of patients remains with a suboptimal response to medical treatment due to primary non-response, secondary loss of response or intolerance to currently available drugs. Identifying, prior to treatment initiation, which patients are likely to respond to a specific drug would improve the disease management, avoid unnecessary side effects and reduce the healthcare expenses. Precision medicine classifies individuals into subpopulations according to clinical and molecular characteristics with the objective to tailor preventative and therapeutic interventions to the characteristics of each patient. Interventions would thus be performed only on those who will benefit, sparing side effects and expense for those who will not. This review aims to summarize clinical factors, biomarkers (genetic, transcriptomic, proteomic, metabolic, radiomic or from the microbiota) and tools that could predict disease progression to guide towards a step-up or top-down strategy. Predictive factors of response or non-response to treatment will then be reviewed, followed by a discussion about the optimal dose of drug required for patients. The time at which these treatments should be administered (or rather can be stopped in case of a deep remission or in the aftermath of a surgery) will also be addressed. IBD remain biologically complex, with multifactorial etiopathology, clinical heterogeneity as well as temporal and therapeutic variabilities, which makes precision medicine especially challenging in this area. Although applied for many years in oncology, it remains an unmet medical need in IBD.

Long-Term Outcomes of Early vs Delayed Responders to Vedolizumab and Adalimumab: A Post Hoc Analysis of the VARSITY Study

INTRODUCTION

It is uncertain whether patients with ulcerative colitis (UC) and delayed symptomatic response to therapy have as robust and durable a response as earlier responders to therapy. We compared clinical outcomes of early and delayed responders to vedolizumab and adalimumab for patients with moderate-severe UC.

METHODS

This was a post hoc analysis of the VARSITY study. Patients with early partial Mayo score (PMS) remission (PMS ≤1 at week 4/6 of therapy) were compared with those with delayed PMS remission (PMS ≤1 at week 14 and not week 4/6). Differences in proportions of patients achieving week 52 clinical remission (CR) (PMS = 0), endoscopic improvement (EI) (Mayo endoscopic subscore ≤1), and histoendoscopic mucosal improvement (HEMI) (Mayo endoscopic subscore ≤1 and Geboes score highest grade <3.2) were assessed. Confounders were adjusted for using multivariate logistic regression.

RESULTS

A total of 147 vedolizumab-treated and 110 adalimumab-treated patients attained early or late PMS remission. Those who attained early PMS remission with vedolizumab were more likely to attain week 52 CR than participants with delayed PMS remission with vedolizumab (69.1% [67/97] vs 50.0% [25/50], aOR 2.43 [95% CI 1.11-5.33], P = 0.027). Week 52 HEMI was more likely among early vedolizumab PMS remitters (63.9% [62/97] vs 40.0% [20/50], aOR 2.60 [95% CI 1.20-5.62], P = 0.015). Week 52 EI was similar between early and delayed PMS remitters to vedolizumab. No differences were observed in week 52 CR, EI, or HEMI between early and delayed PMS remitters to adalimumab.

DISCUSSION

Patients with UC who achieve early PMS remission with vedolizumab have greater odds of week 52 remission compared with delayed responders.

Therapeutic Drug Monitoring in Practice for Inflammatory Bowel Disease

PURPOSE OF REVIEW

To outline the development, rationale, and practical use of therapeutic drug monitoring in patients with inflammatory bowel disease.

RECENT FINDINGS

Therapeutic drug monitoring is traditionally discussed in terms of a proactive or reactive approach. However, these terms are not always consistently defined and can be confusing when translating research to clinical practice. Personalized approaches incorporating clinical context and precision medicine are emerging. Personalized therapeutic drug monitoring combines a structured and proactive strategy for monitoring biologic concentrations as well as identification of antidrug antibody development or subtherapeutic dosing in the setting of loss of response. Optimizing biologic therapy can improve outcomes and avoid loss of response. Why, when, and how we measure drug troughs and anti-drug antibodies is a moving target, though what is known is that the appropriate and evidence-based use of this practice prevents adverse events and improves outcomes in patients with inflammatory bowel disease.

Efficacy of Infliximab Dose Escalation in Patients with Refractory Immunotherapy-Related Colitis: A Case Series

Immune checkpoint inhibitor-related colitis is a common complication of immunotherapy use in patients with cancer. Current guidelines recommend treatment with standard dose infliximab (IFX) for corticosteroid-refractory colitis; however, this case series suggests IFX dose escalation may be a viable treatment option for refractory cases.

Antibodies-to-infliximab accelerate clearance while dose intensification reverses immunogenicity and recaptures clinical response in paediatric Crohn's disease

BACKGROUND

Antibodies to infliximab (ATI) are associated with secondary loss of response and increased risk for drug reactions. Limited studies have associated ATI with increased infliximab clearance.

AIMS

We assessed the impact of ATI on infliximab clearance and loss of response in an inception paediatric Crohn's disease cohort with 1-year follow-up.

METHODS

This multi-centre prospective cohort study collected peak and trough serum infliximab/ATI concentrations from 660 infusions (78 patients) during the first year of therapy. Clinicians were blinded to these research labs. The primary outcome was the difference in infliximab clearance between ATI-positive (ATI) and ATI-negative (no-ATI) patients. Secondary outcomes included pre-treatment predictors of ATI (including HLA-DQA1 genotyping). Clinical remission, loss of response and infliximab clearance were compared between pre-ATI, during ATI and following ATI resolution with MANOVA. Time to ATI was calculated by Cox proportional Hazards model.

RESULTS

ATI were detected in 68% (53/78) patients with a median concentration of 76 ng/mL (range 23-1828). Maximum ATI concentration was <200 ng/mL in 73.6% (39/53). Median clearance in ATI patients was higher (with higher clearance if loss of response), compared to no-ATI patients (P < 0.001). Neutrophil CD64 ratio >6 and starting dose <7.5 mg/kg independently predicted ATI in multivariable regression, while HLA-DQA1*05 presence did not. Dose adjustment resolved ATI in 37.5% (12/32) patients with concomitant infliximab concentration and clearance recovery. A maximum ATI level of ≤99 ng/mL predicted ATI resolution (area under the receiver operating curve 0.80 [95% CI 0.64-0.96]).

CONCLUSIONS

In this real-world cohort, ATI as low as 23 ng/mL impacted drug clearance. Our data suggest that dose optimisation for low-level ATI can improve infliximab clearance and prevent loss of response.

Discontinuation of Azathioprine could be considered in pediatric patients with Crohn's disease who have sustained clinical and deep remission

Few studies have demonstrated treatment strategies about the duration and cessation of medications in patients with Crohn's disease (CD). We investigated factors affecting clinical relapse after infliximab (IFX) or azathioprine (AZA) withdrawal in pediatric patients with CD on combination therapy. Pediatric patients with moderate-to-severe CD receiving combination therapy were analyzed retrospectively and factors associated with clinical relapse were investigated. Discontinuation of IFX or AZA was performed in patients who sustained clinical remission (CR) for at least two years and achieved deep remission. A total of 75 patients were included. Forty-four patients (58.7%) continued with combination therapy and 31 patients (41.3%) discontinued AZA or IFX (AZA withdrawal 10, IFX withdrawal 15, both withdrawal 6). Cox proportional-hazards regression and statistical internal validation identified three factors associated with clinical relapse: IFX cessation (hazard ratio; HR 2.982, P = 0.0081), IFX TLs during maintenance therapy (HR 0.581, P = 0.003), 6-thioguanine nucleotide (6-TGN) level (HR 0.978, P < 0.001). However, AZA cessation was not associated with clinical relapse (P = 0.9021). Even when applied in pediatric patients who met stringent criteria, IFX cessation increased the relapse risk. However, withdrawal of AZA could be contemplated in pediatric patients with CD who have sustained CR for at least 2 years and achieved deep remission.

Nailfold Capillaroscopy as a Biomarker in the Evaluation of Pediatric Inflammatory Bowel Disease

BACKGROUND

Noninvasive screening and disease monitoring are an unmet need in pediatric inflammatory bowel disease (IBD). Nailfold capillaroscopy (NFC) is a validated technique for microvascular surveillance in rheumatologic diseases. NFC uses magnified photography to examine nail bed capillaries called end row loops (ERL). We aimed to identify variations in NFC in pediatric IBD patients and their associations with disease activity.

METHODS

Pediatric patients with Crohn's disease (CD) or ulcerative colitis (UC) and healthy controls were recruited. NFC was performed on patients with newly diagnosed IBD prior to initiating therapy, patients with established IBD, and controls. ERLs were quantified along with a 3mm distance on 8 nailfolds. Serum biomarker levels of disease activity and symptoms activity indexes were correlated with average ERL density digits on both hands. Statistics were performed using chi-squared, ANOVA, and linear regression.

RESULTS

Fifty-one IBD patients and 16 controls were recruited. ERL density was significantly decreased in IBD (Control: 19.2 ERL/3mm vs UC: 15.6 ERL/3mm vs CD: 15.4 ERL/3mm; P < .0001). ERL density was lower in UC patients with lower albumin levels (P = .02, r ² = 0.29).The change in ERL density over time predicted the change in pediatric CD activity index among CD patients (P = .048, r ² = 0.58) with treatment.

CONCLUSIONS

Our data demonstrate ERL density is reduced in IBD compared to controls. Lower albumin levels correlated with lower ERL density in UC. In newly diagnosed CD, ERL density increases over time as disease activity improves with therapy. NFC may be a feasible biomarker of disease activity and utilized for monitoring IBD.

Albumin-to-Globulin Ratio at 1 Year after Anti-Tumor Necrosis Factor α Therapy Can Serve as a Prognostic Biomarker in Pediatric Crohn's Disease Patients

Background/Aims

The efficacy of biologics for the treatment of Crohn's disease (CD) is affected by the drug concentrations. We aimed to evaluate the importance of albumin and globulin which are known to be associated with drug concentrations as prognostic biomarkers in CD.

Methods

In total, 121 pediatric patients with CD who had received anti-tumor necrosis factor (TNF)-α therapy were retrospectively examined between January 2010 and February 2019.

Results

Relapse was observed in 48.8% of patients (59/121). The level of calprotectin (odds ratio, 2.13; p=0.03) and the albumin-to-globulin ratio (AGR) at 1 year after anti-TNF-α therapy (odds ratio, 0.0002; p=0.003) were associated with relapse. The AGR at 1 year after anti-TNF-α therapy was the only factor associated with the time-to-relapse (hazard ratio, 0.02; p<0.001). The optimal AGR cutoff value for the prediction of relapse was 1.47 (area under the curve, 0.916; p<0.001). The median infliximab trough level (TL) was lower in patients with AGRs <1.47 than in those with AGRs ≥1.47. Anti-drug antibody (ADA) concentrations were negatively correlated with the AGR at 1 year of anti-TNF-α therapy (r=-0.413, p=0.032).

Conclusions

AGR can be used to predict relapse. Patients with AGRs <1.47 at 1 year after anti-TNF-α therapy are more likely to have low drug TLs and develop ADAs, which increase the possibility of relapse than those with AGRs ≥1.47. Therefore, if the AGR at 1 year after anti-TNF-α therapy is less than 1.47, clinicians should monitor disease activity, assess the TLs of the anti-TNF-α agents, test for ADAs and determine the appropriate therapeutic strategies.

Shifting Health Care Use from Hospitalisations and Surgeries to Outpatient Visits in Children with Inflammatory Bowel Disease: A Population-based Cohort Study from Ontario, Canada

BACKGROUND

Modern, specialised care for children with inflammatory bowel disease [IBD] may have resulted in changes in health services use. We report trends over time in health services utilisation and surgery for children with IBD and children without IBD.

METHODS

Children aged <18 years, diagnosed with IBD between 1994 and 2013 [n = 5518] and followed until 2015 in Ontario, Canada, were identified from health administrative data and matched to children without IBD on age, sex, rural/urban household, and income [n = 26,677]. We report the annual percentage change [APC] with 95% confidence intervals [CI] in the rate of outpatient visits, emergency department [ED] visits, and hospitalisations, using negative binomial regression for events within 5 years from the diagnosis/index date. We used Cox proportional hazards regression models to report APC in hazards of intestinal resection [Crohn's disease; CD] and colectomy [ulcerative colitis; UC].

RESULTS

IBD-specific hospitalisation rates decreased by 2.5% [95% CI 1.8-3.2%] annually, and all-cause hospitalisation rates in children without IBD decreased by 4.3% [95% CI 3.5-5.1%] annually. Intestinal resection risk in CD decreased by 6.0% [95% CI 4.6-7.3%] annually and colectomy risk in UC decreased by 3.0% [95% CI 0.7-5.2%] annually. In contrast, IBD-specific outpatient visit rates increased after 2005 by 4.0% [95% CI 3.1-4.9%] annually. Similar trends in outpatient visits were not observed in children without IBD.

CONCLUSIONS

Hospitalisations and surgeries decreased over time while outpatient visits increased after 2005. Decreasing hospitalisations were mirrored in children without IBD, likely resulting from a combination of changes in disease management and health system factors.

Treatment of acute severe ulcerative colitis using accelerated infliximab regimen based on infliximab trough level: A case report

BACKGROUND

Acute severe ulcerative colitis (ASUC) is a complication of ulcerative colitis associated with high levels of circulating tumor necrosis factor alpha, due to the intense inflammation and faster stool clearance of anti-tumor necrosis factor drugs. Dose-intensified infliximab treatment can be beneficial and is associated with lower rates of colectomy. The aim of the study was to present a case of a patient with ASUC and megacolon, treated with hydrocortisone and accelerated scheme of infliximab that was monitored by drug trough level.

CASE SUMMARY

A 22-year-old female patient diagnosed with ulcerative colitis, presented with diarrhea, rectal bleeding, abdominal pain, vomiting, and distended abdomen. During investigation, a positive toxin for Clostridium difficile and colonic dilatation of 7 cm consistent with megacolon were observed. She was treated with oral vancomycin for pseudomembranous colitis and intravenous hydrocortisone for severe colitis, which led to the resolution of megacolon. Due to the persistent severe colitis symptoms, infliximab 5 mg/kg was prescribed, monitored by drug trough level (8.8 μg/mL) and fecal calprotectin of 921 μg/g (< 30 μg/g). Based on the low infliximab trough level after one week from the first infliximab dose, the patient received a second infusion at week 1, consistent with the accelerated regimen (infusions at weeks 0, 1, 2 and 6). We achieved a positive clinical and endoscopic response after 6 mo of therapy, without the need for a colectomy.

CONCLUSION

Infliximab accelerated infusions can be beneficial in ASUC unresponsive to the treatment with intravenous corticosteroids. Longitudinal studies are necessary to define the best therapeutic drug monitoring and treatment regimen for these patients.

Immune Protection of a Helminth Protein in the DSS-Induced Colitis Model in Mice

Inflammatory bowel disease (IBD) increases the risk of colorectal cancer, and it has the potential to diminish the quality of life. Recent clinical and experimental evidence demonstrate protective aspects of parasitic helminth infection against IBD. Reports have highlighted the potential use of helminths and their byproducts as potential treatment for IBD. In the current study, we studied the effect of a newborn larvae-specific serine protease from Trichinella spiralis (TsSp) on the host immune and inflammatory responses. A 49-kDa recombinant TsSp (rTsSp) was expressed in Escherichia coli BL21 (DE3) and purified. The cytotoxicity of rTsSp was analyzed. The immune protective effect of rTsSp was studied by using dextran sodium sulfate (DSS)-induced mouse colitis model. The result illustrated that rTsSp has no toxic effects on cells. We further demonstrated that administration of the rTsSp without the additional adjuvant before the induction of DSS-induced colitis reduced the severity of intestinal inflammation and the disease index; it suppressed macrophage infiltration, reduced TNF-α secretion, and induced IL-10 expression. Our findings suggest therapeutic potential of rTsSp on colitis by altering the effect of macrophages. Data also suggest immunotherapy with rTsSp holds promise for use as an additional strategy to positively modulate inflammatory processes involved in IBD.

Soluble ligands as drug targets for treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is characterized by persistent inflammation in a hereditarily susceptible host. In addition to gastrointestinal symptoms, patients with IBD frequently suffer from extra-intestinal complications such as fibrosis, stenosis or cancer. Mounting evidence supports the targeting of cytokines for effective treatment of IBD. Cytokines can be included in a newly proposed classification "soluble ligands" that has become the third major target of human protein therapeutic drugs after enzymes and receptors. Soluble ligands have potential significance for research and development of anti-IBD drugs. Compared with traditional drug targets for IBD treatment, such as receptors, at least three factors contribute to the increasing importance of soluble ligands as drug targets. Firstly, cytokines are the main soluble ligands and targeting of them has demonstrated efficacy in patients with IBD. Secondly, soluble ligands are more accessible than receptors, which are embedded in the cell membrane and have complex tertiary membrane structures. Lastly, certain potential target proteins that are present in membrane-bound forms can become soluble following cleavage, providing further opportunities for intervention in the treatment of IBD. In this review, 49 drugs targeting 25 distinct ligands have been evaluated, including consideration of the characteristics of the ligands and drugs in respect of IBD treatment. In addition to approved drugs targeting soluble ligands, we have also assessed drugs that are in preclinical research and drugs inhibiting ligand-receptor binding. Some new types of targetable soluble ligands/proteins, such as epoxide hydrolase and p-selectin glycoprotein ligand-1, are also introduced. Targeting soluble ligands not only opens a new field of anti-IBD drug development, but the circulating soluble ligands also provide diagnostic insights for early prediction of treatment response. In conclusion, soluble ligands serve as the third-largest protein target class in medicine, with much potential for the drugs targeting them.

Optimal Management of Acute Severe Ulcerative Colitis (ASUC): Challenges and Solutions

Acute severe colitis is a severe complication of ulcerative colitis, affecting approximately 20% of patients. For physicians, it remains a challenging condition to treat. Current treatment algorithms have diminished the mortality associated with acute severe ulcerative colitis (ASUC), but colectomy rates remain high (approximately 30%) despite advances in therapy. Colectomy in ASUC is particularly associated with important postoperative complications and morbidity. In this review, reasons for the inability to improve care and avoid evolution to colectomy for ASUC are explored and solutions that might lead to a better management of the disease are investigated.

Treatment of acute severe ulcerative colitis

Acute severe ulcerative colitis (ASUC) is a potentially life-threatening medical emergency. Due to the increasing incidence of ulcerative colitis in recent years, ASUC has become increasingly common in clinical practice. Presently, corticosteroids remain the first choice, whose efficacy should be evaluated after 3 d. If unsatisfactory, it should be switched to infliximab or cyclosporine salvage treatment timely. Besides, colectomy may be an option when medical treatment is ineffective or serious complications occur. This review describes the current treatment regimens for ASUC, with an aim to help develop treatment plans and improve the prognosis and life quality of patients with ASUC .

Predicting Therapeutic Response in Pediatric Ulcerative Colitis-A Journey Towards Precision Medicine

Ulcerative colitis (UC) is a disabling disease, characterized by chronic inflammation of the colon, with a rising prevalence worldwide in the pediatric age group. Although UC presents in children with varying severity, disease extent, and comorbidities, initial treatment is essentially uniform, consisting of 5-aminosalicylate drugs with corticosteroid induction for those with moderately to severely active disease. With the advent of anti-tumor necrosis factor (TNF) biologic therapy and several new biologics and small-molecule drugs for UC, precision medicine approaches to treatment are needed to more rapidly achieve sustained remission, restore quality of life, normalize development, and limit exposure to toxic corticosteroids in children with UC. Here, we review available data on clinical, biochemical, histopathologic, and molecular predictors of treatment response in UC. We also address known predictors and special treatment considerations in specific relevant scenarios such as very-early-onset UC, acute severe UC, ileal pouch anal anastomosis, and UC with concomitant primary sclerosing cholangitis. The review concludes with a prediction of how machine learning will integrate multimodal patient data to bring precision medicine to the bedside of children with UC in the future.

Therapeutic drug monitoring of anti-tumour necrosis factor-α agents in inflammatory bowel disease: Limits and improvements

AIMS

Since the publication of the American Gastroenterological Association's recommendations in 2017, there have been no significant changes in the biological monitoring recommendations in inflammatory bowel disease. Possible limitations are the lack of evidence to recommend proactive therapeutic drug monitoring (pTDM) over reactive TDM (rTDM), and the limited information about individualized dosing methods. This article aims to review the TDM strategy updates and the use of individualized dosing methods.

METHODS

For the analysis of the TDM strategies and individualized dosing method, a search was carried out in PubMed and Cochrane Central. In the TDM case, since August 2017.

RESULTS

A total of 263 publications were found, but only 7 related to proactive TDM. Five of these publications directly compared pTDM vs rTDM and 2 were randomized clinical trials. Six studies found benefits of pTDM and 1 found no differences. Regarding the individualized dosing method, 229 distinct results were found. Population pharmacokinetics was the most widely used method to develop individual dosage models and to analyse the influence of factors on drug concentrations (albumin concentration, weight, presence of anti-drug antibodies etc).

CONCLUSION

We have found no major changes in TDM strategies. There is a growing trend towards the use of pTDM because it has shown a longer duration of treatment response, lower rates of discontinuation and relapses. However, the available evidence is limited and of low quality. Despite the common use of population pharmacokinetic methods to analyse pharmacokinetic factors, they are not commonly used for personalized dosing.

Long-term effectiveness and pharmacokinetics of the infliximab biosimilar CT-P13 after switching from the originator during the treatment of inflammatory bowel disease

OBJECTIVE

Switching patients from the originator infliximab to a biosimilar is a measure to expand access to treatments and counteract its negative impact on healthcare budgets. However, industry-independent long-term studies on the effect of switching in real life to support the lack of switch-related problems in inflammatory bowel disease (IBD) patients are sparse, as are studies addressing infliximab pharmacokinetic behaviour. The objectives were to investigate the effectiveness and the pharmacokinetics of CT-P13 after switching from originator infliximab in a real-world population of IBD patients with a follow-up of 2 years.

METHOD

Prospective, single-centre, observational 2 year study conducted in IBD adult patients with stable disease treated with the originator infliximab who were switched to CT-P13. Four time points were defined for follow-up: prior to the switch, 4-8 weeks after the switch, 8 months later, and 2 years later. Outcome measures were the proportion of patients with clinical, endoscopic and biochemical remission, and changes in biochemical inflammation markers (albumin, C-reactive protein, faecal calprotectin) and infliximab clearance.

RESULTS

42 IBD patients were switched, of which 36 (85.7%) remained on CT-P13 throughout the 2 year study period. Only two patients discontinued CT-P13 due to loss of response. The proportion of patients who displayed clinical, endoscopic and biochemical remission were unchanged during the follow-up (p<0.05) and no statistically significant changes were observed in the biochemical markers of disease activity. The median (IQR) clearance estimated for the infliximab originator before the change was 0.364 (0.321-0.415) L/day, and for the CT-P13 biosimilar it was 0.361 (0.323-0.415) L/day 4-8 weeks after the change, and 0.370 (0.334-0.419) L/day 2 years after (p=0.395).

CONCLUSION

Switching from originator infliximab to biosimilar CT-P13 did not affect the long-term clinical outcomes or the pharmacokinetic behaviour. This information provides the clinician more evidence for the success of switching and supports non-medical switching in adult IBD patients.

Clinical efficacy of infliximab level and anti-infliximab antibody measurement in patients with inflammatory bowel disease: An audit

BACKGROUND AND AIMS

Infliximab (IFX) monitoring has been proposed for effective therapeutic management of inflammatory bowel disease (IBD). There is no data on infliximab levels and its antibody measurement in Indian patients. We assessed the clinical efficacy of IFX level and antibodies to infliximab (ATI) monitoring in IBD patients.

METHODS

Infliximab trough level and antibody testing was done in 50 and 30 IBD patients, respectively using commercially available enzyme-linked immunosorbent assay (ELISA) kits. The levels were correlated with the disease status, albumin, and C-reactive protein (CRP) levels. The clinical efficacy of level-based change in patient management was evaluated.

RESULTS

Of 50 patients, IFX levels were therapeutic in 8, sub-therapeutic in 40, and supra-therapeutic in 2. High ATI titer was present in 8/30 patients. The IFX level did not correlate with the dose of 5 or 10 mg/kg. Based on IFX level and ATI estimation, management was changed in 35 patients: increase in dose in 7, decrease in dosing interval in 17, increase in interval in 2, surgery in 2, change in biologic in 5, and cessation of IFX in 2 patients. Therapy modification based on IFX level improved the clinical response in 25 patients, of whom 5 are in remission at a median duration of 2 years.

CONCLUSION

Most (80%) of the IBD patients had subtherapeutic IFX levels while high ATI titers were found in 27% of the patients. There was no correlation between infliximab dose and drug levels. Therapy modification based on drug level benefitted the majority. Our results suggest that measurement of IFX level assists in attaining therapeutic levels and improves clinical response.

Personalizing Treatment in IBD: Hype or Reality in 2020? Can We Predict Response to Anti-TNF?

The advent of anti-TNF agents as the first approved targeted therapy in the treatment of inflammatory bowel disease (IBD) patients has made a major impact on our existing therapeutic algorithms. They have not only been approved for induction and maintenance treatment in IBD patients, but have also enabled us to define and achieve novel therapeutic outcomes, such as combination of clinical symptom control and endoscopic remission, as well as mucosal healing. Nevertheless, approximately one third of treated patients do not respond to initiated anti-TNF therapy and these treatments are associated with sometimes severe systemic side-effects. There is therefore the currently unmet clinical need do establish predictive markers of response to identify the subgroup of IBD patients, that have a heightened probability of response. There have so far been approaches from different fields of IBD research, to descry markers that would empower us to apply TNF-inhibitors in a more rational manner. These markers encompass findings from disease-related and clinical factors, pharmacokinetics, biochemical markers, blood and stool derived parameters, pharmacogenomics, microbial species, metabolic compounds, and mucosal factors. Furthermore, changes in the intestinal immune cell composition in response to therapeutic pressure of anti-TNF treatment have recently been implicated in the process of molecular resistance to these drugs. Insights into factors that determine resistance to anti-TNF therapy give reasonable hope, that a more targeted approach can then be utilized in these non-responders. Here, IL-23 could be identified as one of the key factors determining resistance to TNF-inhibitors. Growing insights into the molecular mechanism of action of TNF-inhibitors might also enable us to derive critical molecular markers that not only mediate the clinical effects of anti-TNF therapy, but which level of expression might also correlate with its therapeutic efficacy. In this narrative review, we present an overview of currently identified possible predictive markers for successful anti-TNF therapy and discuss identified molecular pathways that drive resistance to these substances. We will also point out the necessity and difficulty of developing and validating a diagnostic marker concerning clinically relevant outcome parameters, before they can finally enter daily clinical practice and enable a more personalized therapeutic approach.

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

PURPOSE

Infliximab (IFX) therapy in inflammatory bowel disease (IBD) is associated with loss of response in half the patients, due to complex pharmacokinetic and immunological factors. Dashboard's Bayesian algorithms use information from model and individual multivariate determinants of IFX concentration and can predict dose and dosing interval.

AIM

To compare measured IFX concentrations in our laboratory with values predicted by iDose dashboard system and report its efficacy in managing patients not responding to conventional dosing schedule.

METHOD

Clinical history, demographic details, and laboratory findings such as albumin and C-reactive protein (CRP) data of IBD patients (n = 30; median age 23 years (IQR: 14.25 - 33.5)) referred for IFX drug monitoring in our laboratory from November 2017 to November 2019 were entered in iDose software. The IFX concentration predicted by iDose based on this information was compared with that measured in our laboratory. In addition, a prospective dashboard-guided dosing was prescribed in 11 of these 30 patients not responding to conventional dosing and was followed to assess their clinical outcome.

RESULT

IFX monitoring in our 30 patients had shown therapeutic concentration in 12, supratherapeutic in 2 and subtherapeutic concentration in 16 patients. The iDose predicted concentration showed concordance in 21 of these 30 patients. Of 11 patients managed with iDose-assisted prospective dosing, 8 achieved clinical remission, 2 showed partial response, and one developed antibodies.

CONCLUSION

Retrospective data analysis showed concordance between laboratory measured and iDose-predicted IFX level in 70% of patients. iDose-assisted management achieved clinical remission and cost reduction.

Biological therapy in pediatric age

Biological therapies, especially blocking tumor necrosis factor-α (TNFα) agents have radically changed the therapeutic approach and disease course of pediatric inflammatory bowel disease (IBD). In particular, drugs such as infliximab (IFX) and adalimumab (ADA) have been demonstrated to be effective in inducing and maintaining corticosteroid-free remission in both adult and pediatric patients with Crohns Disease (CD) and Ulcerative colitis (UC). Biosimilar biological (BioS) therapy is increasingly being used in pediatric age even though most knowledge on the safety and efficacy of these agents is based on IFX in adult IBD data. Studies show high rates of clinical response and remission in both IFX naïve patients and in patients switched from originator to BioS with similar risks of adverse events (AEs) as those reported with IFX originator. In the present review indications, efficacy and AEs of biological therapy in pediatric IBD will be discussed, as well as the role of other biological agents such as Golimumab, Vedolizumab and Ustekinumab, the role of BioS biological therapy and utility of therapeutic drug monitoring in clinical practice.

The effect of early trough level of infliximab on subsequent disease course in patients with Crohn disease: A prospective cohort study

Decreased trough level of infliximab (TLI) is associated with diminished efficacy in patients with Crohn disease (CD). We examined whether TLI at 14 weeks subsequent to the start of infliximab (IFX) treatment would impact long-term clinical course.Serum IFX levels and antibodies to IFX (ATI) at 14 and 54 weeks after IFX administration were measured in 12 patients with mild to moderate CD. We examined patient background, clinical severity, blood test values, and the relationship between ATI and TLI up to 108 weeks.We compared the group with TLI < 3 μg/mL at 14 weeks (TLI(14) < 3 group) the group with TLI > 3 μg/mL (TLI(14) ≥ 3 group). Patients in the TLI(14) ≥ 3 group were significantly more likely to use immunomodulators before IFX treatment induction (P = .01). At 54 weeks, 2 cases of ATI production were observed in the TLI(14) < 3 group, but no ATI production was observed in the TLI(14) ≥ 3 group. TLI in the TLI(14) ≥ 3 group at 54 weeks was significantly higher than in the TLI(14) < 3 group (6.5 μg/mL vs 1.0 μg/mL; P < .01). Although CD activity index and serum albumin values in the TLI(14) ≥ 3 group at 14, 54, and 108 weeks significantly improved compared to baseline, these improvements were not observed in the TLI(14) < 3 group. The remission maintenance rate at 108 weeks evaluated with the Kaplan-Meier method was significantly higher in the TLI(14) ≥ 3 group than the TLI(14) < 3 group (100% vs 33.3%; P = .02).The TLI 14 weeks after IFX treatment in patients with CD affects long-term outcome.

Bayes-based dosing of infliximab in inflammatory bowel diseases: Short-term efficacy

AIMS

Therapeutic drug monitoring of infliximab can guide clinical decisions in patients with loss of response and in those who can benefit from a de-intensification. The aim of this study was to determine the impact of therapeutic drug monitoring combined with Bayesian forecasting methodology on clinical response in a real-world dataset of patients suffering from inflammatory bowel disease.

METHODS

We performed a single-centre prospective study with one-group pre-test/post-test design in 108 adult inflammatory bowel disease patients treated with model-based dosing of infliximab maintenance treatment. We recorded clinical activity scores (Harvey-Bradshaw index and partial Mayo) and inflammatory biomarkers per patient.

RESULTS

The initial infliximab regimen was maintained in 49 (45.4%) patients and was adjusted in 59 (54.6%) patients (34 treatment intensifications, 9 de-intensifications and 16 treatment discontinuations or therapy replacements). The median time from intervention to index measurement was 126 (103-160) days. The overall proportion of patients in clinical remission increased from 65.7% to 80.4% (P < .0001) and the median infliximab trough concentrations increased from 3.21 (0.99-5.45) to 5.13 mg/L (3.57-6.53) (P < .0001). In the intensified group, the remission rate increased from 35.3% to 61.8% (P = .001) and the percentage of patients in clinical remission or with mild symptoms increased from 76.5% to 94.1%. In the de-intensification cohort, no patients experienced an increase in the Harvey-Bradshaw index or partial Mayo scores, and all patients maintained an infliximab trough concentration of >5 mg/L.

CONCLUSION

In our cohort of inflammatory bowel disease patients, Bayes-based optimized dosing improved the short-term efficacy of infliximab treatment.

The Treatment of Pediatric Inflammatory Bowel Disease with Biologic Therapies

PURPOSE OF REVIEW

Biologics for the treatment of inflammatory bowel disease (IBD) have been transformative to the therapeutic goals in the pediatric population. We review the biologics used to treat IBD, highlighting the importance of patient selection, dosing considerations, and therapeutic drug monitoring in children.

RECENT FINDINGS

Infliximab is well-established as a safe and efficacious therapy for Crohn's disease and ulcerative colitis. Both dose escalation strategies and therapeutic drug monitoring increase the likelihood of response to anti-TNFα therapies. Early real-world experience of vedolizumab and ustekinumab in pediatric IBD shows promising results, including clinical response rates comparable to what is seen in adults, but there are limited data using them as first-line therapies. Biologic therapies have improved outcomes in pediatric IBD, including achieving mucosal healing as well as improved growth and pubertal development. Therapeutic drug monitoring improves likelihood of response to anti-TNFα therapies, but further studies for vedolizumab and ustekinumab are necessary.

A 3-year prospective study of a multidisciplinary early proactive therapeutic drug monitoring programme of infliximab treatments in inflammatory bowel disease

AIMS

Therapeutic drug monitoring (TDM) of trough serum infliximab concentrations has been mainly used in case of loss of response in patients with inflammatory bowel disease (IBD). The aim of this study was to evaluate the effectiveness and safety of a multidisciplinary early proactive TDM (mep-TDM) programme for dose adjustment.

METHODS

A 3-year prospective study was conducted based on a sample of 81 patients who started treatment and were subsequently subjected to mep-TDM with the first control at week 14. Data of a historical control group of 72 patients treated with infliximab and managed with empirical dosing were included. Effectiveness variables were treatment failure, IBD-related surgery and IBD-related hospitalization. Safety variables were serious infusion reactions (SIRs) and adverse reactions. Cox regression was used for survival analysis.

RESULTS

In the mep-TDM study group, compared to the control group, there was a significant reduction in the risk of treatment failure (hazard ratio [HR]: 0.51; 95% confidence interval [CI]: 0.27-0.92; P = .037), IBD-related surgery (HR: 0.14; 95% CI: 0.03-0.65; P = .012) and hospitalization (HR: 0.38; 95% CI: 0.17-0.87; P = .022). SIRs were lower in the mep-TDM group (2.5% vs 10.4%; P < .050); the incidence of adverse reactions was similar (3.7% vs 3.9%; p > .999).

CONCLUSION

This study found that compared to empirical dosing, mep-TDM is associated with improved efficacy and safety of infliximab therapy, reduced IBD-related hospitalization and surgery and incidence of SIRs, and increasing long-term durability of treatment effects.

Proactive Infliximab Drug Monitoring Is Superior to Conventional Management in Inflammatory Bowel Disease

BACKGROUND

Increasing evidence supports the use of reactive therapeutic drug monitoring (TDM) in Crohn's disease (CD) and ulcerative colitis (UC) following secondary loss of response. It is still unknown if proactive TDM can improve clinical outcomes.

METHODS

Consecutive patients completing infliximab (IFX) induction therapy were prospectively allocated into a proactive TDM protocol (pTDM). Before the fourth infusion and every 2 infusions, IFX trough levels and antidrug antibodies were measured using a drug-sensitive assay (Theradiag, Lisa Tracker). Treatment was proactively escalated aiming at an IFX trough level between 3 and 7 ug/mL (CD) and 5 and 10 ug/mL (UC). A retrospective cohort treated with IFX but without TDM served as the reference group. End points included the need for surgery, hospitalization, treatment discontinuation, and mucosal healing at 2 years of follow-up.

RESULTS

Two hundred five patients were included, 56 in the proactive regimen. Treatment escalation was more common in pTDM patients (76.8% vs 25.5%; P < 0.001), who also required less surgery (8.9% vs 20.8%; P = 0.032) and presented higher rates of mucosal healing (73.2% vs 38.9%; P < 0.0001). Proactive TDM significantly decreased the odds of reaching any unfavorable outcome (odds ratio, 0.358; 95% confidence interval, 0.188-0.683; P = 0.002).

CONCLUSIONS

Proactive TDM is associated with fewer surgeries and higher rates of mucosal healing than conventional non-TDM-based management.

Therapeutic drug monitoring with vedolizumab in inflammatory bowel disease

Therapeutic drug monitoring (TDM) is a useful tool for decision-making process in patients with inflammatory bowel disease (IBD) treated with anti TNF-α drugs, especially when experiencing loss of response. Growing evidences support the existence of exposure-response relationship with vedolizumab, but the utility and the appropriate use of TDM in clinical practice is still under debate. In this review, we summarize all evidences supporting a TDM-guided approach for patients treated with vedolizumab, suggesting three potential scenarios: 1) early prediction of long-term outcomes; 2) verifying the best strategy in case of loss of response; 3) maximizing therapeutic efficacy during maintenance treatment. Vedolizumab through concentrations <20 µg/mL at week 6 and >12 µg/mL seem to be associated with more favorable outcomes. No comparative studies have been conducted so far to demonstrate the advantage of adopting a TDM-guided versus an empirical approach for managing primary or secondary nonresponses. The frequency of antibodies to vedolizumab detection is quite low (up to 4% in pivotal trials), suggesting, unlike of anti TNF-α agents, a low probability of experiencing an immune-mediated pharmacokinetic failure in clinical practice. Future prospective and controlled studies are warranted to establish the guidance on the use of a TDM-guided approach with vedolizumab in clinical practice.

Early Dose Optimisation of Golimumab in Nonresponders to Induction Treatment for Ulcerative Colitis Is Effective and Supported by Pharmacokinetic Data

BACKGROUND AND AIMS

In nonresponders to golimumab induction for ulcerative colitis, we assessed clinical response rates and golimumab serum concentrations when the 100-mg dose was used early in the course of maintenance.

METHODS

This post-hoc analysis of golimumab maintenance dosing [in the PURSUIT-M study] examined clinical outcomes and golimumab concentrations in early [Week 6] responders and nonresponders to induction, including subgroups based on body weight.

RESULTS

In nonresponders to golimumab induction [assessed at Week 6], the 100-mg maintenance dose [starting at Week 6] resulted in a meaningful proportion [28.1%] of patients achieving a partial Mayo response at Week 14. After 1 year of maintenance, clinical outcome [response, remission, mucosal healing, corticosteroid-free state] rates in these "late" [Week 14] responders were similar to those in early [Week 6] responders. Golimumab concentrations in early nonresponders were approximately half those of early responders, suggesting that early nonresponders had more rapid golimumab clearance. Examined by body weight, the early nonresponders weighing <80 kg and receiving 100 mg had golimumab concentrations similar to the early responders [weighing <80 kg or ≥80 kg and receiving 50 mg or 100 mg, respectively].

CONCLUSIONS

Early use of the 100-mg maintenance dose leads to positive clinical outcomes in a meaningful proportion of patients who did not respond to golimumab at Week 6. Early nonresponders <80 kg who received the 100-mg maintenance dose achieved adequate golimumab concentrations and a clinically meaningful proportion of these patients had a late clinical response.PURSUIT-M protocol number C0524T18; ClinicalTrials.gov, NCT00488631; EudraCT, 2006-003399-37.

Infliximab induction regimens in steroid-refractory acute severe colitis: a multicentre retrospective cohort study with propensity score analysis

BACKGROUND

Accelerated induction regimens of infliximab have been proposed to improve response rates in patients with steroid-refractory acute severe colitis.

AIM

To determine the differences in outcome for acute severe ulcerative colitis between accelerated and standard-dose infliximab METHODS: We collected data on hospitalised patients receiving differing regimens of rescue therapy for steroid-refractory acute severe ulcerative colitis. Our primary outcome was 30-day colectomy rate. Secondary outcomes were colectomy within index admission, and at 90 days and 12 months. We used propensity score analysis with optimal calliper matching using high risk covariates defined a priori to reduce potential provider selection bias.

RESULTS

We included 131 patients receiving infliximab rescue therapy; 102 received standard induction and 29 received accelerated induction. In the unmatched cohort, there was no difference by type of induction in the 30-day colectomy rates (18% vs 20%, P = .45), colectomy during index admission (13% vs 20%, P = .26) or overall colectomy (20% vs 24%, P = .38). In the propensity score-matched cohort of 52 patients, 30-day colectomy (57% vs 27%, P = .048) and index admission colectomy (53% vs 23%, P = .045) rates were higher in those receiving standard induction compared to accelerated induction but there was no difference in overall colectomy rates (57% vs 31%, P = .09). There was no significant difference in length of stay or in complication and infection rates.

CONCLUSION

In a propensity score-matched cohort, steroid-refractory acute severe ulcerative colitis patients, short-term, but not long-term, colectomy rates appear to be lower in those receiving an accelerated induction regimen.

Practice pattern variability in the management of acute severe colitis: a UK provider survey

INTRODUCTION

Lack of comparative trial data on dosing regimens of infliximab in patients with acute severe ulcerative colitis (ASUC) failing intravenous corticosteroids has resulted in variability of rescue regimes in ASUC with potential impact on clinical outcomes. We aimed to evaluate practice variability and physician perspectives in decision-making with rescue therapy.

METHODOLOGY

An internet-based survey of members of the inflammatory bowel disease (IBD) section of the British Society of Gastroenterology was conducted. The survey evaluated provider characteristics and general practice in the setting of ASUC, followed by a vignette with linked questions.

RESULTS

The response rate of the survey was 31% (209/682 IBD section members). 134 (78%) reported they would use standard infliximab dose (5 mg/kg) while 37 (22%) favoured a higher front-loading dose of 10 mg/kg citing low albumin, high C-reactive protein as their reason for their preference. IBD specialists chose the higher front-loading dose more often compared with other gastroenterologists (p=0.01) In the specific case vignette, accelerated induction (AI) was favoured by 51% of the respondents while 25% used the standard induction regime and 19% favoured colectomy. IBD specialists more often favoured AI compared with other gastroenterologists (p=0.03) with the main reason being presence of predictors of low infliximab levels (74%). The reasons cited for favouring standard induction (n=57) included lack of evidence for AI (18), their usual practice (11), unlicensed regime (7), and safety concerns (4).

CONCLUSIONS

There are significant variations in practice in the use of infliximab rescue therapies with an urgent need for development of care pathways to standardise practice.

Effectiveness of vedolizumab dose intensification to achieve inflammatory bowel disease control in cases of suboptimal response

BACKGROUND

Despite the proven efficacy of vedolizumab (VDZ) for ulcerative colitis (UC) and Crohn's disease (CD), suboptimal response is commonly encountered. However, data regarding the effectiveness of dose intensification (by interval shortening) to achieve response are limited.

OBJECTIVES

We evaluated the effectiveness of dose intensification at achieving response in patients with a previously suboptimal response to VDZ. Additionally, we aimed to identify predictors of response to this strategy.

METHODS

We performed a retrospective cohort study of patients who underwent VDZ dose intensification for suboptimal response. Clinical disease activity was evaluated at the point of dose intensification (baseline) and at weeks 12 and 24. Response was defined as Harvey-Bradshaw Index (HBI) or Simple Clinical Colitis Activity Index (SCCAI) reduction of ≥3, and remission as HBI <5 or SCCAI <3.

RESULTS

A total of 36 patients received dose intensification to 4-weekly infusions: 18 CD, 14 UC and 4 inflammatory bowel disease-unclassified (analysed in the UC group). Median SCCAI scores fell from 6 (range 0-11) at baseline to 4 (0-6, p=0.008) at week 24, while HBI scores did not change significantly (4 (0-27) and 3 (0-8), p=0.092). Overall median C reactive protein (CRP) fell from 6 mg/L (1-23) to 2 mg/L (1-17, p=0.011). Of 20 patients with clinically active disease at baseline, 10 (50%) responded, of whom 4 (20%) achieved remission at week 24. Univariate analysis demonstrated low baseline CRP (p=0.045) and response at week 12 (0.020) were associated with week 24 response.

CONCLUSIONS

Our findings demonstrate VDZ dose intensification to be effective at achieving clinical response in half of patients. Low baseline CRP and response at week 12 are potential predictors of week 24 response.

Systematic Review: Efficacy and Safety of Accelerated Induction Regimes in Infliximab Rescue Therapy for Hospitalized Patients with Acute Severe Colitis

BACKGROUND

Pharmacokinetic data suggest that standard induction dosing schedules may not be sufficient in patients with acute severe colitis (ASUC). Hence, intensified induction regimes are increasingly used in the rescue treatment of hospitalized patients with ASUC to avoid the need for colectomy although the evidence for this is uncertain.

AIM

To conduct a systematic review of short- and long-term efficacy outcomes from accelerated infliximab induction studies.

METHODS

Systematic search of relevant databases (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews) and relevant conference proceedings (Digestive Diseases Week, European Colitis and Crohn's Organisation Congress, United European Gastroenterology Week) was done.

RESULTS

We identified ten relevant studies with a total of 705 patients, of whom 308 received an intensified infliximab regime. Pooled analysis showed no difference in short-term or long-term colectomy rates in those receiving accelerated induction regimes when compared to standard induction. No significant differences in complication rates were identified.

CONCLUSIONS

The available uncontrolled studies so far do not suggest short-term or long-term benefit in using accelerated induction in hospitalized ASUC. The overall poor quality of available studies with confounding variables indicates the need for a randomized controlled trial with personalized risk stratification.

Mechanisms of molecular resistance and predictors of response to biological therapy in inflammatory bowel disease

Biological therapy has led to marked improvements in treatment of patients with inflammatory bowel disease, and an increasing number of drugs has been approved for treatment. However, only a subgroup of patients responds to therapy, highlighting the need to identify biomarkers for therapeutic response to allow personalised medicine in inflammatory bowel disease. Potential markers of response to biological therapy have been identified; however, studies also suggest that changes in the composition of immune cell infiltrates in response to therapeutic pressure lead to molecular resistance to these drugs. For instance, the cytokine interleukin 23 has been identified as a driver of evasion of apoptosis in response to anti-tumour necrosis factor drugs in patients with Crohn's disease, leading to expansion of apoptosis-resistant T cells and drug resistance. In this Review, we examine the concept of molecular resistance to biological therapy and discuss implications for future therapy.

Has infliximab influenced the course and prognosis of acute severe ulcerative colitis?

Ulcerative colitis (UC) still has no definitive cure since its etiology remains unclear. In recent years, considerable progress has been made with regard to our knowledge of the pathogenesis of UC. Advances in biotechnology have led to the development of biologic therapies which selectively target single key mediators or receptors involved in the pathogenesis of the disease - ie, tumor necrosis factor (TNF)-α, integrin, interleukins 12/23. Biologic therapies caused a revolution in the treatment of UC, providing specific options for patients refractory to conventional treatment. In recent years, antibodies anti-TNFα and anti-integrin have shown efficacy in improving the course and prognosis of ambulatory patients with moderate-to-severe UC. Nevertheless, whether biologics have brought so many benefits also for hospitalized patients with acute severe UC is still debated. Acute severe UC is a potentially life-threatening condition that affects up to 25% of patients during the course of their disease. It requires hospital admission due to the risk of complications and death, and it can necessitate urgent colectomy. Major adverse outcomes of acute severe UC are mortality and colectomy. The aim of this systematic review of the literature was to analyze the impact of biologics, in particular infliximab, on the course and prognosis of acute severe UC. Mortality and colectomy rates were considered as outcome measures.

High-Dose Infliximab Rescue Therapy for Hospitalized Acute Severe Ulcerative Colitis Does Not Improve Colectomy-Free Survival

BACKGROUND AND OBJECTIVE

Optimization strategies with infliximab (IFX) are increasingly used as rescue therapy for steroid refractory acute severe ulcerative colitis (ASUC). We aim to determine if intensified IFX induction improves colectomy rate and identifies outcome predictors.

METHODS

Hospitalized adult patients who received IFX for ASUC between 2010 and 2016 were identified. We compared standard inductions (5 mg/kg) vs high-dose induction (10 mg/kg) with 3-month colectomy rate as primary outcome.

RESULTS

Seventy-two patients (62.5% male, median age 38.5) were identified. Thirty-seven patients (51.3%) received 5 mg/kg IFX and 35 received 10 mg/kg. Baseline clinical, biochemical and endoscopic parameters were well matched between these two groups. 10 mg/kg was more likely to be used by clinicians from 2014 onwards (p < 0.001). Three-month colectomy rate was 9.7%; which was not significantly different between the standard (5.4%) and high-dose (14.3%) IFX induction (p = 0.205). CRP ≥ 60 (OR 10.9 [95% CI 1.23-96.50], p = 0.032), hemoglobin ≤ 90 g/L (OR 15.6 [95% CI 2.61-92.66], p = 0.036) and albumin < 30 g/L (OR 9.4 [95% CI 1.06-83.13], p = 0.044) were associated with increased risk of colectomy at 3 months in univariate regression analysis.

CONCLUSION

Use of high-dose infliximab rescue therapy did not improve 3-month colectomy-free survival in this cohort. Tailored use in high-risk patients may be beneficial although further validation is required.

Optimal management of acute severe ulcerative colitis

Acute severe ulcerative colitis is a life-threatening medical emergency, which can be associated with significant morbidity and is preventable through prompt and effective management. Corticosteroids remain the cornerstone of initial therapy, although a third of patients will not respond. Further management hinges on timely decisions with use of rescue therapy with ciclosporin or infliximab, without compromising the health or safety of the patient, or timely surgery. Although such patients need specialist care, it is imperative that emergency care physicians are aware of the important principles of management of this condition to achieve successful outcomes. Risk stratification and the use of predictive models using clinical parameters have reduced the morbidity associated with this condition.We discuss current evidence and present a clinical approach to clinicians involved in the emergency care of patients with acute severe ulcerative colitis in this review.