Induction infliximab levels among patients with acute severe ulcerative colitis compared with patients with moderately severe ulcerative colitis

Therapeutic drug monitoring in inflammatory bowel diseases. Position statement of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis

The treatment of inflammatory bowel disease has undergone a significant transformation following the introduction of biologic drugs. Thanks to these drugs, treatment goals have evolved from clinical response and remission to more ambitious objectives, such as endoscopic or radiologic remission. However, even though biologics are highly effective, a significant percentage of patients will not achieve an initial response or may lose it over time. We know that there is a direct relationship between the trough concentrations of the biologic and its therapeutic efficacy, with more demanding therapeutic goals requiring higher drug levels, and inadequate exposure being common. Therapeutic drug monitoring of biologic medications, along with pharmacokinetic models, provides us with the possibility of offering a personalized approach to treatment for patients with IBD. Over the past few years, relevant information has accumulated regarding its utility during or after induction, as well as in the maintenance of biologic treatment, in reactive or proactive strategies, and prior to withdrawal or treatment de-escalation. The aim of this document is to establish recommendations regarding the utility of therapeutic drug monitoring of biologics in patients with inflammatory bowel disease, in different clinical practice scenarios, and to identify areas where its utility is evident, promising, or controversial.

Acute severe ulcerative colitis management: unanswered questions and latest insights

Acute severe ulcerative colitis (ASUC) is a distinctive ulcerative colitis flare presentation characterised by the presence of systemic inflammation as well as bloody diarrhoea, and occurs at least once in 25% of patients with ulcerative colitis during their disease course. Each episode carries a risk of complications, need for colectomy, and mortality. Little is known about ASUC pathogenesis, although impaired host-microbiota crosstalk involving pathobionts is suspected. In this Review, we discuss unanswered questions and results from the latest research on the medical-first-line, second-line, and potential third-line therapies-and surgical management of ASUC. We detail promising options for management, such as the use of enteral nutrition in combination with intravenous steroids, the ability to predict early failure of first-line or second-line therapies, and the emerging role of JAK inhibitors. An optimal framework to personalise therapy on the basis of multiomics tools is yet to be developed.

Modern practical management of acute severe colitis

Acute severe ulcerative colitis (ASUC) is one of life-threatening complications that occur in one-fifth of ulcerative colitis (UC) patients with significant morbidity and an estimated mortality rate up to 1%. There are no validated clinical scoring systems for ASUC. Intravenous corticosteroids remain the cornerstone for the management of ASUC patients However, one-third of patients are steroid refractory and require colectomy in the pre-biologic era or salvage therapy in the post-biologic era. The currently available predictors of non-response to steroids and salvages therapy are sub-optimal. Furthermore, there is a need for the development of clear outcome measures for ASUC patients. Although infliximab and cyclosporin are both effective as salvage therapy, they still carry a rate of treatment failure. Hence, there is an unmet need to explore alternative therapeutic options before colectomy particularly in prior infliximab-exposed patients. This may include the introduction of small molecules with rapid onset of action as a salvage or sequential therapy and the use of slow-onset other biological therapy after "bridging" with cyclosporine. In this article, we explore the current best evidence-based practice and detail the gaps in knowledge in the management of ASUC.

Infliximab Induction Strategies in Corticosteroid-Refractory Acute Severe Ulcerative Colitis: A Case Series and Literature Review

Acute severe ulcerative colitis (ASUC) is an emergent medical condition and particularly challenging to treat efficaciously. Infliximab is one of the medical salvage treatment options after corticosteroid refractoriness, but the best induction strategy is not yet defined. With this case series, the authors intend to describe three corticosteroid-refractory ASUC cases with different intensified/accelerated infliximab induction approaches and review the literature on this topic. The first case describes an 18-year-old girl with ASUC at disease onset with rapid progression to toxic megacolon, complicated also with anemia, hypoalbuminemia, and coagulopathy. After corticosteroid failure, both accelerated and intensified (10 mg/kg) infliximab regimen was completed within 11 days, with solid clinical response and colon imaging normalization. Second, we present a 26-year-old male with left-sided ulcerative colitis known for 2 years, under mesalazine, who developed a moderate flare and was started on infliximab after partial and inconsistent response to corticosteroids. During the induction period, he presented this time an ASUC episode, which motivated an early and intensified third dose with good clinical response. Finally, we describe the case of a 78-year-old man with ulcerative proctitis for 12 years presenting ASUC with proximal disease extension as well. After unsatisfactory response to corticosteroids, infliximab was initiated on an accelerated induction regimen, completed in 13 days, with the standard dose, achieving clinical remission. Accelerated or intensified infliximab induction plans are becoming current clinical practice in corticosteroid-refractory ASUC. Current guidelines refer to the possibility of this type of strategies, not determining the optimal regimen due to lack of solid evidence. Literature is mainly based on retrospective studies, not randomized, with heterogeneous groups according to disease severity, and the effect on colectomy rates, mainly on the long term, is not clear. Additional well-supported studies are needed on this subject in order to seek a more widely uniform approach.

Factors Associated With Response to Rescue Therapy in Acute Severe Ulcerative Colitis

BACKGROUND

Acute severe ulcerative colitis (ASUC) is a medical emergency for which colectomy is required in patients who do not respond to rescue therapy. While previous studies have predominantly focused on predicting outcome to first-line corticosteroid therapy, there is a need to understand the factors associated with response to rescue therapies in order to improve clinical outcomes. We reviewed the evidence regarding factors associated with response to rescue therapy in adults with ASUC and identified future directions for research.

METHODS

A systematic search of the literature was conducted, and 2 reviewers independently assessed studies for inclusion.

RESULTS

Of 3509 records screened, 101 completed studies were eligible for inclusion. We identified 42 clinical, hematological, biochemical, endoscopic, or pharmacological factors associated with response to rescue therapy. Older age (≥50 years), thiopurine experience, and cytomegalovirus or Clostridioides difficile infection were associated with a higher risk of nonresponse to rescue therapy. Biochemical factors associated with poorer response included an elevated C-reactive protein (CRP) ≥30mg/L on admission, hypoalbuminemia and an elevated ratio of CRP to albumin. Severe endoscopic findings, including a Mayo endoscopic score of 3 or Ulcerative Colitis Endoscopic Index of Severity ≥5, portended poorer outcomes. The role of fecal calprotectin and therapeutic value of measuring infliximab drug levels in ASUC remain to be defined.

CONCLUSIONS

Response to rescue therapy can be predicted by several specific factors, which would aid clinical decision-making. Existing and emerging factors should be integrated within predictive and prognostic models to help improve clinical outcomes.

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.

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.

Multi-utility of therapeutic drug monitoring in inflammatory bowel diseases

Inflammatory bowel disease (IBD) treatment targets have progressed over time from clinical response to clinical and endoscopic remission. Several data have shown a positive correlation between serum biologic drug concentrations and favorable therapeutic outcomes. Therapeutic drug monitoring (TDM) has evolved as an important approach for optimizing the use of immunobiologics, especially antitumor necrosis factor therapy, in patients with IBD. The use of TDM is supported by medical societies and IBD experts in different contexts; however, challenges remain due to knowledge gaps that limit the widespread use of it. The aim of this review is to assess the role of TDM in IBD, focusing on the implementation of this strategy in different scenarios and demonstrating the multi-utility aspects of this approach in clinical practice.

Optimizing Therapies Using Therapeutic Drug Monitoring: Current Strategies and Future Perspectives

Therapeutic drug monitoring (TDM) has emerged as a strategy for treatment optimization in inflammatory bowel diseases to maximize benefit and to reach more stringent, objective end points. Optimal drug concentrations in inflammatory bowel disease vary according to treatment target, disease phenotype, inflammatory burden, and timing of sampling during the treatment cycle. This review provides an update on TDM with biologic and oral small molecules, evaluates the role of reactive vs proactive TDM, and identifies the gaps in current evidence. In the future, adaptations to how we use TDM may contribute further to the goal of personalized treatment in patients with IBD.

Therapeutic Drug Monitoring of Biologics in IBD: Essentials for the Surgical Patient

Despite significant development in the pharmacological treatment of inflammatory bowel diseases (IBD) along with the evolution of therapeutic targets and treatment strategies, a significant subset of patients still requires surgery during the course of the disease. As IBD patients are frequently exposed to biologics at the time of abdominal and perianal surgery, it is crucial to identify any potential impact of biological agents in the perioperative period. Even though detectable serum concentrations of biologics do not seem to increase postoperative complications after abdominal procedures in IBD, there is increasing evidence on the role of therapeutic drug monitoring (TDM) in the perioperative setting. This review aims to provide a comprehensive summary of published studies reporting the association of drug concentrations and postoperative outcomes, postoperative recurrence (POR) after an ileocolonic resection for Crohn’s disease (CD), colectomy rates in ulcerative colitis (UC), and perianal fistulizing CD outcomes in patients treated with biologics. Current data suggest that serum concentrations of biologics are not associated with an increased risk in postoperative complications following abdominal procedures in IBD. Moreover, higher concentrations of anti-TNF agents are associated with a reduction in colectomy rates in UC. Finally, higher serum drug concentrations are associated with reduced rates of POR after ileocolonic resections and increased rates of perianal fistula healing in CD. TDM is being increasingly used to guide clinical decision making with favorable outcomes in many clinical scenarios. However, given the lack of high quality data deriving mostly from retrospective studies, the evidence supporting the systematic application of TDM in the perioperative setting is still inconclusive.

Therapeutic drug monitoring in inflammatory bowel disease: The dawn of reactive monitoring

Inflammatory bowel disease (IBD) is a chronic condition that significantly affects the quality of life of its patients. Biologic drugs have been the mainstay treatment in the management of IBD patients but despite their significant contribution, there remains a proportion of patients that do not respond or lose response to treatment. Therapeutic drug monitoring (TDM) involves measuring levels of serum drug concentrations and anti-drug antibodies. TDM of biologic drugs initially emerged to understand treatment failure in other immune mediated inflammatory diseases. This was then introduced in IBD to rationalize primary non-response or secondary loss of response, given that low serum drug concentrations or the formation of anti-drug antibodies are variably associated with treatment failure. The aim of this narrative review is to provide an overview regarding the current use of TDM in clinical practice and to present the evidence available regarding its use in both proactive and reactive clinical settings in preventing and managing treatment failure. This review also presents the existing evidence regarding the association of various clinical outcomes with specific thresholds of drug concentrations, in everyday practice. A narrative review of published articles and conference abstracts regarding the use of TDM in IBD management, through an electronic search using PubMed and ScienceDirect. TDM has proven to be superior and more cost effective in guiding management of patients with treatment failure compared to empiric dose escalation or change in treatment. Despite a trend towards an association between clinical outcomes and drug concentrations, proactive TDM based strategies have not been shown to achieve clear benefit in long-term outcomes. In the clinical setting, TDM has proven to be useful in managing IBD patients, and its use in the reactive setting, as an additional tool to help manage patients with treatment failure, is being promoted as newer guidelines and consensus groups implement TDM as part of the management plan.

A Comprehensive Literature Review and Expert Consensus Statement on Therapeutic Drug Monitoring of Biologics in Inflammatory Bowel Disease

Therapeutic drug monitoring (TDM) of biologics is a rapidly evolving field. We aimed to provide a consensus statement regarding the clinical utility of TDM for biologics in inflammatory bowel disease (IBD). A modified Delphi method was applied to develop consensus statements. A comprehensive literature review was performed regarding TDM of biologic therapies in IBD, and 45 statements were subsequently formulated on the potential application of TDM in IBD. The statements, along with literature, were then presented to a panel of 10 gastroenterologists with expertise in IBD and TDM who anonymously rated them on a scale of 1-10 (1 = strongly disagree and 10 = strongly agree). An expert consensus development meeting was held virtually to review, discuss, refine, and reformulate statements that did not meet criteria for agreement or that were ambiguous. During the meeting, additional statements were proposed. Panelists then confidentially revoted, and statements rated ≥7 by 80% or more of the participants were accepted. During the virtual meeting, 8 statements were reworded, 7 new statements were proposed, and 19 statements were rerated. Consensus was finally reached in 48/49 statements. The panel agreed that reactive TDM should be used for all biologics for both primary nonresponse and secondary loss of response. It was recommended that treatment discontinuation should not be considered for infliximab or adalimumab until a drug concentration of at least 10-15 μg/mL was achieved. Consensus was also achieved regarding the utility of proactive TDM for anti-tumor necrosis factor therapy. It was recommended to perform proactive TDM after induction and at least once during maintenance. Consensus was achieved in most cases regarding the utility of TDM of biologics in IBD, specifically for reactive and proactive TDM of anti-tumor necrosis factors.

How to manage: acute severe colitis

Acute severe ulcerative colitis (ASUC) is a medical emergency which is associated with significant morbidity and a mortality rate of 1%. ASUC requires prompt recognition and treatment. Optimal management includes admission to a specialist gastrointestinal unit and joint management with colorectal surgeons. Patients need to be screened for concomitant infections and thromboprophylaxis should be administered to mitigate against the elevated risk of thromboembolism. Corticosteroids are still the preferred initial medical therapy but approximately 30%-40% of patients fail steroid therapy and require rescue medical therapy with either infliximab or cyclosporine. Emergency colectomy is required in a timely manner for patients who fail rescue medical therapy to minimise the risk of adverse post-operative outcomes. We discuss current and emerging evidence in the management of ASUC and outline management approaches for clinicians involved in managing ASUC.

Efficacy of dashboard driven dosing of infliximab in inflammatory bowel disease patients; a randomized controlled trial

OBJECTIVES

Loss of response (LOR) to infliximab (IFX) remains a challenge in the management of inflammatory bowel diseases (IBD). Proactive dosing strategies to achieve and maintain predefined IFX trough levels (TL) may prevent LOR. We aimed to investigate the efficacy of dashboard driven IFX dosing compared to standard dosing in a prospective trial in IBD patients.

METHODS

In this multicentre 1:1 'PRECISION' trial, we randomized IBD patients in clinical remission (Harvey Bradshaw Index ≤4 for Crohn's disease (CD) or a partial Mayo score ≤2 for ulcerative colitis (UC)) receiving IFX maintenance treatment. The precision group (PG) received IFX dosing guided by a Bayesian pharmacokinetic model, aiming to achieve and maintain a TL of 3 µg/ml by treatment (de)escalation as indicated by the dashboard. Patients in the control group (CG) continued treatment without dose adaptations. The primary endpoint was the proportion of patients in sustained clinical remission after 1 year.

RESULTS

Eighty patients were enrolled (66 CD, 14 UC), and the median [interquartile range] age was 37 years [27-51]). After one year, 28/32 (88%) of patients in the PG were in sustained clinical remission versus 25/39 (64%) in the CG (p = .017). PG patients had lower median faecal calprotectin levels after 1 year (p = .031), whereas no significant differences in median CRP levels were found.

CONCLUSION

We demonstrated that the use of a Bayesian dashboard for IFX dosing in maintenance treatment for IBD reduced the incidence of LOR compared to standard dosing. Precision dosing also resulted in lower FCP levels.

CLINICALTRIALS.GOV NUMBER

NCT02453776.

Intestinal Microbiota and Perspectives of the Use of Meta-Analysis for Comparison of Ulcerative Colitis Studies

Meta-analysis is a statistical process summarizing comparable data from a number of scientific papers. The use of meta-analysis in microbiology allows decision-making that has an impact on public health policy. It can happen that the primary researches come to different conclusions, although these are targeted with the same research question. It is, therefore, inevitable to have the means to systematically evaluate information and compare research results. Ulcerative colitis together with Crohn's disease are among the two main inflammatory bowel diseases. This chronic disease of the gastrointestinal tract, with an as yet unclear etiology, is presented by an uncontrolled inflammatory immune response in genetically predisposed individuals to as yet undefined environmental factors in interaction with the intestinal microbiota itself. In patients with ulcerative colitis (UC), changes in the composition and relative abundance of microorganisms could be observed. Sulfate-reducing bacteria (SRB), which commonly occur in the large intestine as part of the commensal microbiota of animals and humans involved in the pathogenesis of the disease, have been shown to occur. SRB are anaerobic organisms affecting short-chain fatty acid metabolism. This work outlines the perspectives of the use of meta-analysis for UC and changes in the representation of intestinal organisms in these patients.

Early Serum Infliximab Levels in Pediatric Ulcerative Colitis

Background: Data on serum infliximab concentrations during induction in pediatric ulcerative colitis are limited. The study aim is to evaluate the relationship between serum infliximab concentrations during induction and short-term clinical remission in children with ulcerative colitis. Methods: We carried out a prospective, multi-center cohort study in pediatric patients with ulcerative colitis. Serum infliximab concentrations were collected at peak dose #1, week 1, trough pre-dose #2, and trough pre-dose #3. Infliximab dosing was left to investigator discretion. Clinical remission was defined by pediatric ulcerative colitis activity index <10 at week 8. Results: Twenty-four of thirty-four subjects (71%) achieved clinical remission at week 8. The median infliximab concentrations were 33.0 μg/mL (interquartile range: 26.5-52.1 μg/mL) pre-dose #2 and 22.5 μg/mL (interquartile range:15.9-32.3 μg/mL) pre-dose #3. Trough pre-dose #2 infliximab concentration yielded area under receiver operator characteristic curve 0.7, 95% CI: 0.5-0.9 in predicting week 8 clinical remission; a cut-off of 33.0 μg/mL yielded 62.5% sensitivity, 66.7% specificity. Trough pre-dose #3 infliximab concentrations were lower for subjects <10 years compared to ≥ 10 years [median 15.9 μg/mL, interquartile range (IQR) 8.5-21.8 μg/mL vs. 27.7 μg/mL, IQR 17.2-46.7 μg/mL, p = 0.01] and correlated with baseline weight (Spearman's rank correlation coefficient 0.45, p = 0.01). The median half-life following first IFX dose was 6.04 days (IQR 5.3-7.9 days). Conclusions: Infliximab concentrations ≥33 μg/mL prior to the second dose were associated with week 8 clinical remission. As young age and low body weight impact infliximab concentration, prospective studies with proactive adjustment in pediatric patients with ulcerative colitis should be carried out. Clinicians caring for children with UC should diligently adjust and monitor infliximab to optimize response.

Optimizing biologic therapy in IBD: how essential is therapeutic drug monitoring?

Proposed treatment targets for the management of inflammatory bowel disease (IBD) have moved beyond symptomatic improvement towards more objective end points, such as healing of the intestinal mucosa. This treat-to-target approach has been associated with improved disease outcomes such as diminished bowel damage, surgery and hospitalizations. Many patients with IBD require biologic therapy to achieve and maintain clinical and endoscopic remission, and antitumour necrosis factor antibodies remain the first-line biologic therapy in most areas of the world. Unfortunately, up to one-third of patients receiving this treatment are primary non-responders, and some patients that show an initial response can also lose response over time. Therapeutic drug monitoring (TDM) has been suggested as a useful tool to manage patients on antitumour necrosis factor treatment, including monitoring for dose escalation, de-escalation or to switch treatment. In this Perspective, we aim to summarize evidence and guidelines related to TDM in IBD management and also discuss potential strategies to optimize biologic treatment where TDM is not available.

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.

Usefulness of monitoring antitumor necrosis factor serum levels during the induction phase in patients with Crohn's disease

AIMS

The aims of this study were (a) to know the kinetics of antitumor necrosis factor (TNF) drug serum levels during the induction phase in patients with Crohn's disease; (b) to identify variables associated with these levels; and (c) to assess the relation between these levels and short-term effectiveness in Crohn's disease patients.

METHODS

Patients with Crohn's disease naïve to anti-TNF treatment were prospectively included. Remission was defined as a Crohn's disease activity index (CDAI) score <150 after 14 weeks of treatment. Blood samples were obtained at baseline and at weeks 4, 8, and 14. Adalimumab and infliximab levels were measured, receiver operating characteristic (ROC) curves were constructed, and the area under the ROC curve was calculated.

RESULTS

One-hundred fifty patients with Crohn's disease were included, 79 (53%) received infliximab and 71 (47%) had CDAI > 150 at study entry. At week 14, 52 out of 71 patients with CDAI > 150 at baseline (73%) had clinical remission. There were no differences in infliximab levels between patients with and without remission (8 vs. 9.1 μg/mL, P > 0.05) or with and without response (7 vs. 11 μg/mL, P > 0.05) at week 14. There was a trend to higher levels of adalimumab concentration in responders in comparison with nonresponders (13 vs. 6.7 μg/mL, P = 0.05) and in patients who achieved remission in comparison with nonremitters (13.5 vs. 8.4 μg/mL, P = 0.06). In the multivariate analysis, no variable was predictive of short-term remission, including infliximab and adalimumab serum levels.

CONCLUSION

Determining anti-TNF serum levels during the induction phase is not useful for predicting short-term remission in patients with Crohn's disease.

Infliximab in acute severe colitis: getting the right dose

Acute severe colitis is a medical emergency and requires prompt treatment with intravenous steroids. Infliximab is typically used as rescue therapy in those who fail to respond to corticosteroids. This article outlines the altered pharmacokinetics of infliximab in acute severe UC and summarised the latest published data surrounding accelerated infliximab dosing.

Post-induction infliximab trough levels and disease activity in the clinical evolution of pediatric ulcerative colitis

BACKGROUND AND AIMS

Recent adult evidence suggests that infliximab (IFX) trough levels (TL) in patients with severe ulcerative colitis (UC) may be decreased. The aims of our study were to compare post-induction IFX TL of children with severe versus moderate UC and to evaluate short- and long-term outcomes.

METHODS

In this single-center retrospective study, children with a diagnosis of UC starting IFX with a Pediatric Ulcerative Colitis Activity Index (PUCAI) ≥35 and with available post-induction TL were recruited. UC characteristics, IFX dosage and interval, primary non-response, IFX failure, and surgery after 24 months were collected. Post induction TL, anti-IFX antibodies, and laboratory evaluations at the time of starting IFX were also acquired.

RESULTS

A total of 90 children were enrolled, of whom 39 (43.3%) were classified as severe UC and 51 (56.6%) as moderate UC. Median post-induction IFX TL were lower in severe UC versus moderate group (5.5 vs 10.3; p = 0.03), despite a more frequently intensified IFX regimen. Children in the higher TL quartiles showed increased rates of clinical, biological, and combined remission (p = 0.04, p < 0.001, and p = 0.01, respectively). In a multivariate analysis, a PUCAI ≥65 and time interval from last IFX infusion were the only predictors associated with IFX TL. At 24 months, children in the higher TL quartiles had a decreased risk of IFX failure (p = 0.002). The severe UC group showed a higher risk of IFX failure at 24 months (16/23 (41%) vs. 11/40 (21.6%); p = 0.05). Kaplan-Meier methods demonstrated a trend toward statistical significance, with a two-year cumulative colectomy rate of 15.38% (95% confidence interval (CI) 8.1-15.6%) in children with severe UC and 3.92% (95% CI 2.9-10.8%) in patients with moderate UC (logrank test p = 0.06).

CONCLUSIONS

Children starting IFX with severe UC showed lower post-induction TL and poor disease outcomes. Achieving adequate TL was associated with better efficacy outcomes.

High Remission Rate with Infliximab and Plant-Based Diet as First-Line (IPF) Therapy for Severe Ulcerative Colitis: Single-Group Trial

INTRODUCTION

About one-third of patients with severe ulcerative colitis (UC) do not respond to corticosteroid therapy and receive rescue therapy with infliximab or cyclosporine. Up to 20% of such patients fail to respond to rescue therapy and undergo colectomy.

OBJECTIVE

We investigated the outcomes of infliximab and a plant-based diet (PBD) as first-line therapy for severe UC.

METHODS

Patients with severe UC defined by the Truelove and Witts criteria were admitted and given standard induction therapy with infliximab (5.0 mg/kg-7.5 mg/kg) at 0, 2, and 6 weeks. Additionally, they received a PBD. The primary endpoint was remission or colectomy in the induction phase and 1 year after discharge. Secondary endpoints were changes in inflammatory markers in the induction phase and the PBD score at baseline and follow-up. A higher PBD score indicates greater adherence to a PBD.

RESULTS

Infliximab and PBD as first-line therapy was administered in 17 cases. The remission rate was 76% (13/17), and the colectomy rate was 6% (1/17) in the induction phase. C-reactive protein values and the erythrocyte sedimentation rate significantly decreased at week 6 from 9.42 mg/dL to 0.33 mg/dL and from 59 to 17 mm/h, respectively (p < 0.0001). At 1-year follow-up, the cumulative relapse rate was 25%, and there were no additional colectomy cases. Mean PBD scores of 27.7 at 1 year and 23.8 at 4 years were significantly higher than baseline scores of 8.3 and 9.9, respectively (p < 0.0001 and p = 0.0391).

CONCLUSION

This new first-line therapy for severe UC demonstrated a higher remission rate and lower colectomy rate than with the current modality.

Special considerations for biologic medications in pediatric ulcerative colitis

Introduction: More extensive disease, high rates of corticosteroid refractory and dependent disease, and the potential impact of disease on growth and development differentiate inflammatory bowel disease in children from adults. This is particularly evident in ulcerative colitis where pancolitis predominates, success of mesalamine alone in achieving remission is less than 50%, and there is a high need for immunomodulator or biologic therapies.Areas Covered: This review describes the use of infliximab, adalimumab, golimumab, and vedolizumab in the treatment of children with ulcerative colitis but is limited in scope due to the paucity of controlled clinical trials. A search of existing literature with keywords of these specific biological therapies as well as 'pediatric', 'ulcerative colitis,' and 'inflammatory bowel disease' was used to complete this review.Expert Opinion: Therapeutic drug monitoring has become standard of care when assessing dosing and changes in therapy and will play a role in future treatment planning.

Intensified Infliximab Induction is Associated with Improved Response and Decreased Colectomy in Steroid-Refractory Paediatric Ulcerative Colitis

BACKGROUND

Infliximab pharmacokinetics in steroid-refractory [SR] ulcerative colitis [UC] suggest a need for higher dosing, but data concerning efficacy of intensification in this setting are lacking in children and inconsistent overall.

METHODS

Paediatric patients [N = 125] treated with infliximab for SR or steroid-dependent UC were retrospectively reviewed. Outcomes [clinical response and remission, colectomy, mucosal healing, safety] with standard vs intensified induction [mean induction dose ≥7 mg/kg or interval ≤5 weeks between doses 1 and 3] were compared.

RESULTS

Among 125 patients [median age 14 years, median UC duration 0.7 years, 74 SR], 73 [58%] received standard induction and 52 [42%] received intensified induction. Overall, 73 [58%] achieved remission (judged by physician global assessment [PGA] and paediatric UC activity index [PUCAI]≤10]. Among patients in remission, 7 [10%] experienced secondary loss of response by a median of 0.7 [IQR 0.4-1.0] years. Of the 74 SR patients, 17 [23%] underwent colectomy, and of the 51 steroid-dependent patients, 12 [24%] underwent colectomy. Intensified induction in SR patients was associated with a higher chance of remission (hazard ratio [HR] 3.2, p = 0.02) and a lower chance of colectomy [HR 0.4, p = 0.05], but did not improve outcomes in steroid-dependent patients. During follow-up, 46/73 [63%] patients in remission had regimen individualization, with similar rates of return to standard dosing after 1 year between those with initial intensified or standard induction. Follow-up endoscopy, performed in 35/73 patients in remission, demonstrated mucosal healing for 66%. Adverse events were rare, despite use of intensified regimens.

CONCLUSIONS

These data suggest a benefit from intensified infliximab induction specifically among children with steroid-refractory UC. Prospective studies comparing dosing regimens and incorporating therapeutic drug monitoring should be undertaken.

Systematic Review and Meta-analysis: Optimal Salvage Therapy in Acute Severe Ulcerative Colitis

BACKGROUND

Infliximab is an effective salvage therapy in acute severe ulcerative colitis; however, the optimal dosing strategy is unknown. We performed a systematic review and meta-analysis to examine the impact of infliximab dosage and intensification on colectomy-free survival in acute severe ulcerative colitis.

METHODS

Studies reporting outcomes of hospitalized steroid-refractory acute severe ulcerative colitis treated with infliximab salvage were identified. Infliximab use was categorized by dose, dose number, and schedule. The primary outcome was colectomy-free survival at 3 months. Pooled proportions and odds ratios with 95% confidence intervals were reported.

RESULTS

Forty-one cohorts (n = 2158 cases) were included. Overall colectomy-free survival with infliximab salvage was 79.7% (95% confidence interval [CI], 75.48% to 83.6%) at 3 months and 69.8% (95% CI, 65.7% to 73.7%) at 12 months. Colectomy-free survival at 3 months was superior with 5-mg/kg multiple (≥2) doses compared with single-dose induction (odds ratio [OR], 4.24; 95% CI, 2.44 to 7.36; P < 0.001). However, dose intensification with either high-dose or accelerated strategies was not significantly different to 5-mg/kg standard induction at 3 months (OR, 0.70; 95% CI, 0.39 to 1.27; P = 0.24) despite being utilized in patients with a significantly higher mean C-reactive protein and lower albumin levels.

CONCLUSIONS

In acute severe ulcerative colitis, multiple 5-mg/kg infliximab doses are superior to single-dose salvage. Dose-intensified induction outcomes were not significantly different compared to standard induction and were more often used in patients with increased disease severity, which may have confounded the results. This meta-analysis highlights the marked variability in the management of infliximab salvage therapy and the need for further studies to determine the optimal dose strategy.

Pharmacokinetics of golimumab in moderate to severe ulcerative colitis: the GO-KINETIC study

Background: Golimumab (GLM) is approved for the treatment of moderate to severe ulcerative colitis (UC). Higher serum concentrations of anti-tumor necrosis factor (TNF) agents are associated with improved clinical and endoscopic outcomes. Correlations between GLM serum concentrations and clinical and endoscopic outcomes were investigated during induction and maintenance treatment. In addition, a population pharmacokinetic model was developed to identify factors associated with the pharmacokinetics of GLM in UC. Methods: A prospective observational trial (GO-KINETIC) was conducted in patients with moderate to severe UC receiving induction and maintenance treatment with GLM. Clinical and endoscopic outcomes were evaluated, fecal GLM concentrations were measured and pharmacokinetic data were analyzed. Results: A total of 20 patients were enrolled. At week 8 (after induction treatment), 12 out of 20 patients (60%) showed an endoscopic response (≥1 point reduction in endoscopic Mayo score). Patients with endoscopic response at week 8 had numerically higher median GLM serum concentrations at week 2 compared to endoscopic non-responders: 9.1 µg/ml [5.9-12.3] vs. 7.1 µg/mL [5.2-9.0]; p = .384, respectively. At week 52, 3/20 patients (15%) achieved endoscopic remission (endoscopic Mayo score ≤1) and continued GLM treatment. Population pharmacokinetic analysis showed an inverse association between albumin concentrations and GLM clearance. GLM concentrations were undetectable in fecal samples. Conclusions: After induction therapy, 60% of the patients showed endoscopic response. During maintenance therapy, about one third of patients discontinued GLM treatment because of loss of response. These patients might benefit from dose optimization.

A Review on the Use of Anti-TNF in Children and Adolescents with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) presents with disabling symptoms and may lead to insufficient growth and late pubertal development in cases of disease onset during childhood or adolescence. During the last decade, the role of anti-tumor necrosis factor (TNF) in the treatment of paediatric-onset IBD has gained more ground. The number of biologicals presently available for children and adolescents with IBD has increased, biosimilars have become available, and practices in adult gastroenterology with regards to anti-TNF have changed. The aim of this study is to review the current evidence on the indications, judicious use, effectiveness and safety of anti-TNF agents in paediatric IBD. A PubMed literature search was performed and included articles published after 2000 using the following terms: child or paediatric, Crohn, ulcerative colitis, inflammatory bowel disease, anti-TNF, TNF alpha inhibitor, infliximab, adalimumab, golimumab and biological. Anti-TNF agents, specifically infliximab and adalimumab, have proven to be effective in moderate and severe paediatric IBD. Therapeutic drug monitoring increases therapy effectiveness and safety. Clinical predictors for anti-TNF response are currently of limited value because of the variation in outcome definitions and follow-ups. Future research should comprise large cohorts and clinical trials comparing groups according to their risk profile in order to provide personalized therapeutic strategies.

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.

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.

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.

Contemporary Medical Management of Acute Severe Ulcerative Colitis

Acute severe ulcerative colitis is a medical emergency that requires prompt recognition, evaluation, and intervention. Patients require hospital admission with laboratory, radiographic, and endoscopic evaluation with initiation of corticosteroid treatment. Despite early intervention, many patients require salvage medical therapy, with some progressing to colectomy. Here we review important concepts and recent advances in the evaluation and medical management of adult and pediatric patients with acute severe ulcerative colitis.

Wide variation in the use and understanding of therapeutic drug monitoring for anti-TNF agents in inflammatory bowel disease: an inexact science?

BACKGROUND

We aimed to understand the way in which therapeutic drug monitoring (TDM) is used, understood and interpreted for anti-TNF agents in IBD.

RESEARCH DESIGN AND METHODS

We designed an 18-question survey that included 5 TDM-based clinical scenarios, for which the 'most appropriate' responses were based on the BRIDGe groups 'Anti-TNF Optimizer'. This resource combines TDM evidence with expert consensus.

RESULTS

We received 110 complete responses: 50 (45%) consultants, 30 (27%) trainees, 25 (23%) IBD nurse specialists and 5 (5%) gastroenterology pharmacists. Over half (61, 55%) only carry out TDM in non-response. The remainder use TDM routinely, including during stable maintenance therapy for patients in remission. Lower therapeutic thresholds used were variable. Most (82, 75%) were unsure whether their laboratory uses a drug-tolerant or drug-sensitive antidrug antibody assay and few (15, 14%) understand the difference. Consultants, high-frequency users (> 3requests/month) and clinicians with larger anti-TNF cohorts (> 100) were significantly more likely to select the 'most appropriate' answer to at least 1 of the 5 TDM-based clinical scenarios.

CONCLUSIONS

There exists marked heterogeneity in the practical use, understanding and interpretation of biologic TDM. Biologic decision-making, informed by TDM, should involve consultation with experienced clinicians who are frequent TDM users, ideally, as part of a multidisciplinary, biologics-focused IBD meeting.

ABBREVIATIONS

TDM: therapeutic drug monitoring; CNS: clinical nurse specialist; ELISA: enzyme-linked immunosorbent assay; RIA: radioimmunoassays; HMSA: homogenous mobility shift assays; BSG: British Society of Gastroenterology.

Severe endoscopic lesions are not associated with more infliximab fecal loss in acute severe ulcerative colitis

BACKGROUND

It has been observed that early infliximab (IFX) fecal excretion in patients with acute severe ulcerative colitis (ASUC) was associated with low treatment response.

AIM

The objective was to assess if severe endoscopic lesions (SEL) were associated with IFX loss in the stool as well as low IFX concentrations in plasma at day 1 and 2 in a cohort of patients admitted for ASUC.

METHODS

Consecutive patients admitted for a steroid-refractory ASUC requiring IFX and who underwent flexible sigmoidoscopy before starting the drug were included in a case-control, prospective, two-center study. Cases were patients with SEL and controls those without SEL. Plasmatic and fecal IFX concentrations were measured at day 1 and 2.

RESULTS

Among the 15 patients analyzed (10 men; median age: 49 years), 6 were cases harboring SEL at baseline. IFX was detected in the stool in 2/6 (33%) of cases and 4/9 (44%) of controls (p = 1) and no difference was observed between the two groups regarding plasmatic concentrations at day 1 or 2 (p = 1).

CONCLUSION

In ASUC, SEL were not associated with more loss of IFX in the stool or lower plasmatic levels. Early IFX pharmacokinetics in this setting does not seem related to endoscopic severity.

Individualized Dosing of Therapeutic Monoclonal Antibodies-a Changing Treatment Paradigm?

The introduction of monoclonal antibodies (mAbs) to the treatment of inflammatory bowel disease (IBD) was an important medical milestone. MAbs have been demonstrated as safe and efficacious treatments of IBD. However, a large percentage of patients either fail to respond initially or lose response to therapy after a period of treatment. Although there are factors associated with poor treatment outcomes in IBD, one cause for treatment failure may be low mAb exposure. Consequently, gastroenterologists have begun using therapeutic drug monitoring (TDM) to guide dose adjustment. However, while beneficial, TDM does not provide sufficient information to effectively adjust doses. The pharmacokinetics (PK) and pharmacodynamics (PD) of mAbs are complex, with numerous factors impacting on mAb PK and PD. The concept of dashboard-guided dosing based on Bayesian PK models allows physicians to combine TDM with factors influencing mAb PK to individualize therapy more effectively. One issue with TDM has been the slow turnaround of assay results, either necessitating an additional clinic visit for a sample or reacting to TDM results at a subsequent, rather than the current, dose. New point-of-care (POC) assays for mAbs are being developed that would potentially allow physicians to determine drug concentration quickly. However, work remains to understand how to determine what target exposure is needed for an individual patient, and whether the combination of POC assays and dashboards presents a safe approach with substantial outcome benefit over the current standard of care.

Proactive Therapeutic Drug Monitoring of TNF Antagonists in Inflammatory Bowel Disease

BACKGROUND

Proactive therapeutic drug monitoring (TDM) to titrate tumor necrosis factor (TNF) antagonists has emerged recently as a tool to routinely monitor drug concentration to achieve target levels in patients with quiescent inflammatory bowel disease (IBD).

METHODS

The purpose of the present review article was to present available data exploring the concept of proactive TDM.

RESULTS

While several observational studies have identified an association between proactive TDM and better IBD outcomes, 2 randomized controlled studies did not confirm this advantage.

CONCLUSIONS

Based on the evidence to date, proactive TDM cannot be recommended in daily practice. However, analysis is hampered by the low level of evidence for the cutoffs used and the need for point-of-care assays. Regarding economic issues and de-escalating strategies, proactive TDM may have several future indications in IBD. Exploratory studies on proactive TDM with newly available biologic agents in IBD are also awaited.

How to predict response to anti-tumour necrosis factor agents in inflammatory bowel disease

Anti-tumor necrosis factor (TNF) agents have changed the therapeutic approach to inflammatory bowel disease (IBD). However, a considerable proportion of patients either do not primarily respond or lose response to treatment. Despite the long-standing experience in the use of these drugs, still there is the need of identifying the possible predictors of efficacy. Areas covered: We critically review the current knowledge on predictors of response to anti-TNF therapy - both those available in clinical practice and those still under investigation. Multiple factors are involved in treatment success, including disease phenotype and severity, adherence to medications, and pharmacogenomic, pharmacokinetic, and immunologic factors. Literature search was conducted in PubMed using keywords 'inflammatory bowel disease,' 'Crohn's disease,' and 'ulcerative colitis,' matched with 'antitumor necrosis factor,' 'biologic therapy,' 'clinical response,' 'predictors,' and 'efficacy,' Relevant articles were selected for review. Expert commentary: While the role of several factors in clinical practice is clearly established, other investigational markers have been proposed, mostly in small studies, yet for many of them little external validation exists. Therapeutic drug monitoring is emerging as a pivotal strategy to guide decisions in clinical practice. In the near future, novel markers could improve our ability to direct treatment and personalize therapy.

Management of Paediatric Ulcerative Colitis, Part 2: Acute Severe Colitis-An Evidence-based Consensus Guideline From the European Crohn's and Colitis Organization and the European Society of Paediatric Gastroenterology, Hepatology and Nutrition

BACKGROUND AND AIM

Acute severe colitis (ASC) is one of the few emergencies in pediatric gastroenterology. Tight monitoring and timely medical and surgical interventions may improve outcomes and minimize morbidity and mortality. We aimed to standardize daily treatment of ASC in children through detailed recommendations and practice points which are based on a systematic review of the literature and consensus of experts.

METHODS

These guidelines are a joint effort of the European Crohn's and Colitis Organization (ECCO) and the European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN). Fifteen predefined questions were addressed by working subgroups. An iterative consensus process, including 2 face-to-face meetings, was followed by voting of the national representatives of ECCO and all members of the Paediatric Inflammatory Bowel Disease (IBD) Porto group of ESPGHAN (43 voting experts).

RESULTS

A total of 24 recommendations and 43 practice points were endorsed with a consensus rate of at least 91% regarding diagnosis, monitoring, and management of ASC in children. A summary flowchart is presented based on daily scoring of the Paediatric Ulcerative Colitis Activity Index. Several topics have been altered since the previous 2011 guidelines and from those published in adults.

DISCUSSION

These guidelines standardize the management of ASC in children in an attempt to optimize outcomes of this intensive clinical scenario.

Management of Paediatric Ulcerative Colitis, Part 1: Ambulatory Care-An Evidence-based Guideline From European Crohn's and Colitis Organization and European Society of Paediatric Gastroenterology, Hepatology and Nutrition

BACKGROUND

The contemporary management of ambulatory ulcerative colitis (UC) continues to be challenging with ∼20% of children needing a colectomy within childhood years. We thus aimed to standardize daily treatment of pediatric UC and inflammatory bowel diseases (IBD)-unclassified through detailed recommendations and practice points.

METHODS

These guidelines are a joint effort of the European Crohn's and Colitis Organization (ECCO) and the Paediatric IBD Porto group of European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN). An extensive literature search with subsequent evidence appraisal using robust methodology was performed before 2 face-to-face meetings. All 40 included recommendations and 86 practice points were endorsed by 43 experts in Paediatric IBD with at least an 88% consensus rate.

RESULTS

These guidelines discuss how to optimize the use of mesalamine (including topical), systemic and locally active steroids, thiopurines and, for more severe disease, biologics. The use of other emerging therapies and the role of surgery are also covered. Algorithms are provided to aid therapeutic decision-making based on clinical assessment and the Paediatric UC Activity Index (PUCAI). Advice on contemporary therapeutic targets incorporating the use of calprotectin and the role of therapeutic drug monitoring are presented, as well as other management considerations around pouchitis, extraintestinal manifestations, nutrition, growth, psychology, and transition. A brief section on disease classification using the PIBD-classes criteria and IBD-unclassified is also part of these guidelines.

CONCLUSIONS

These guidelines provide a guide to clinicians managing children with UC and IBD-unclassified management to provide modern management strategies while maintaining vigilance around appropriate outcomes and safety issues.

Therapeutic drug monitoring of tumour necrosis factor inhibitors in the management of chronic inflammatory diseases

Tumour necrosis factor inhibitor therapy has drastically changed the management of chronic inflammatory diseases. Some important drawbacks that can cause loss of response during treatment with these drugs are related to their large individual variability, the disease burden and the formation of antidrug antibodies that increase its clearance. Therapeutic drug monitoring of these drugs is not yet recommended by all scientific societies, and if so, only in patients with inflammatory symptoms. Proactive therapeutic drug monitoring represents a new strategy with many potential clinical benefits, including the prevention of immunogenicity, a reduction in the need for rescue therapy and greater durability of tumour necrosis factor inhibitor treatment. The review is based on a systematic search of the literature for controlled trials, systematic reviews, experimental studies, guideline papers and cohort studies addressing the best practice in tumour necrosis factor inhibitor therapeutic drug monitoring. Although there is ample evidence supporting the use of therapeutic drug monitoring in clinical practice to achieve better outcomes, some challenges have been detected. Many studies are focused on finding solutions for the lack of standardization of analytical methods to measure tumour necrosis factor inhibitor and antidrug antibodies concentrations. Other challenges are development of effective cost-saving proactive algorithms to identify optimal drug concentrations and the research on the role of antidrug antibodies, especially in the management and prevention of loss of response. Therapeutic drug monitoring of tumour necrosis factor inhibitor offers a rational approach to the optimization of the treatment of chronic inflammatory disease. Although prospective controlled trials yield little conclusive evidence of its benefits, there is growing acceptance of its value in clinical practice.

Prospective Observational Evaluation of Time-Dependency of Adalimumab Immunogenicity and Drug Concentrations: The POETIC Study

OBJECTIVES

Adalimumab is usually self-injected at home, making prospective serial-sampling studies challenging and scarce. This has led to a gap in knowledge about evolution of anti-adalimumab antibodies (AAAs) over time and its correlation with clinical and inflammatory outcomes.

METHODS

A program for home visits by physicians at induction, every 3 months and at event of relapse, was established prospectively for Crohn's disease (CD) patients. At each visit, patients' clinical scores were determined and sera were obtained for C-reactive protein, drug, and AAA levels. This cohort was compared to a parallel prospective cohort of infliximab-treated CD patients. In a subgroup of 29 patients, trough and in-between-trough levels were compared, to elucidate the importance of timing of sampling during the injection cycle.

RESULTS

Ninety-eight CD patients starting adalimumab were prospectively followed (median follow-up 44 weeks) and 621 serum samples were analyzed. Thirty-three patients (32%) developed AAA; 18/33 (55%) of them as early as week 2, and 26/33 (79%) by week 14. Induction period AAAs were strongly associated with primary non-response (odds ratio (OR) = 5.4, 95% confidence interval (CI): 1.6-17.8, p = 0.005). As compared to antibodies-to-infliximab (ATI), AAA formation rate over time was significantly lower (p = 0.01) and AAA were much more specific-85% of AAA events were associated with loss-of-response compared with 58% rate for ATI (p = 0.01). In 29 patients sampled serially during an injection cycle, levels of drug and AAA seemed comparable between four time-points during a single cycle both in patients with or without AAA (n = 8, n = 21, respectively).

CONCLUSIONS

When followed prospectively and serially, AAAs are found to arise earlier than previously appreciated and their impact may be more pronounced for primary rather than secondary, non-response. Drug and AAA levels were similar both at trough and in-between injections, enabling to simplify therapeutic drug monitoring of adalimumab.

Accelerated Clearance of Infliximab is Associated With Treatment Failure in Patients With Corticosteroid-Refractory Acute Ulcerative Colitis

BACKGROUND AND AIMS

A significant proportion of patients with corticosteroid-refractory acute ulcerative colitis [UC] fail therapy. We aimed to assess the pharmacokinetics [PK] of infliximab [IFX] in patients with corticosteroid-refractory acute UC and determine the association between induction IFX PK and short- and long-term therapy outcome.

METHODS

A population PK model was developed using data from 51 patients with UC [n = 42] and Crohn's disease [n = 9]. A subset of patients [n = 36] with acute corticosteroid-refractory UC (median Mayo score 11 [range 8-12]; 33 of 36 hospitalized; median corticosteroid dose at study entry 50mg prednisolone equivalent IV/oral) commencing IFX were studied to assess further correlations between PK from the first induction dose and therapy outcomes. Serial induction drug levels from the 36 UC patients were collected, facilitating population-based PK analysis. IFX and antibodies-to-infliximab [ATIs] concentrations were determined using AnsrTM IFX assay [Prometheus Inc.].

RESULTS

The Week 14 clinical response and Week 54 corticosteroid-free remission rates were 78% [28/36] and 53% [19/36], respectively. The estimated effective IFX half-life [T1/2] (median [range]) and clearance (median [range]) were 8.42 [3.94-22.03] days and 0.50 [0.19-1.41] L/day respectively. Longer induction IFX T1/2 and lower clearance were associated with the Week 14 clinical response [p = 0.005] and the Week 54 corticosteroid-free remission rates [p = 0.007].

CONCLUSIONS

Accelerated IFX clearance occurs in corticosteroid-refractory acute UC and is associated with therapy failure. These data support the use of accelerated IFX induction regimens in patients with corticosteroid-refractory acute UC failing conventional dosing regimens.

Acute severe ulcerative colitis: State of the art treatment

Acute severe ulcerative colitis (ASUC) is a potentially life-threatening condition. In the present review, we give a broad overview of the state of the art in the management of this condition. A systematic bibliographic search was performed in PubMed. Patient with ASUC should be hospitalized and managed by a multidisciplinary team (gastroenterologist plus surgeon). Intravenous corticosteroids remain the cornerstone of medical therapy. However, about 30% of patients do not respond. After failing 3-5 days of corticosteroids, patients should be considered for either rescue medical therapy or for colectomy. Cyclosporin and infliximab are similarly effective and safe. Cyclosporin should be mainly used as a "bridge" in thiopurine-naïve patients. More recently, infliximab has become the most widely used salvage therapy. Third-line salvage therapy with either cyclosporin or infliximab is efficacious in some patients but carries a significant risk of complications. Colectomy is appropriate in case of complications or medical rescue therapy failure.

Infliximab trough concentrations during maintenance therapy are associated with endoscopic and histologic healing in ulcerative colitis

BACKGROUND

Endoscopic and histologic healing are emerging as new therapeutic goals in ulcerative colitis (UC), as these endpoints are associated with less relapse, hospitalization and colectomy.

AIM

To investigate the association of serum infliximab trough concentrations during maintenance therapy with endoscopic or histologic healing in UC.

METHODS

In this multi-center retrospective cohort study, we included consecutive patients with moderate-to-severe UC on infliximab maintenance therapy who had an endoscopic evaluation and underwent therapeutic drug monitoring within three months of the colonoscopy, between February 2008 and March 2016. Per event analysis was performed. Endoscopic healing was defined as Mayo endoscopic sub-score of ≤1. Histologic healing was defined as no or only focal mild active inflammation.

RESULTS

Seventy colonoscopies from 56 patients were evaluated. Infliximab trough concentrations (median [interquartile range]) were significantly higher in patients with endoscopic (11.3 [7.6-14.5] vs 6.3 [0-9.8] μg/mL, P < .001) or histologic (11.1 [6.7-14.5] vs 6.7 [0-9.9] μg/mL, P = .002) healing, respectively, compared to patients without healing. Receiver-operating characteristic analyses identified infliximab trough concentration thresholds of 7.5 (area under the curve [AUC]: 0.758) and 10.5 (AUC: 0.721) μg/mL to be associated with endoscopic and histologic healing, respectively. Multiple logistic regression analysis identified infliximab trough concentration ≥7.5 (P = .013; odds ratio [OR]: 4.3; 95% confidence intervals [CI]: 1.4-13.3) and ≥10.5 μg/mL (P = .013; OR: 3.8; 95% CI: 1.3-11) as independent factors associated with endoscopic and histologic healing, respectively.

CONCLUSIONS

This study demonstrated that infliximab trough concentrations during maintenance therapy are associated with endoscopic and histologic healing in patients with UC.

Early drug and anti-infliximab antibody levels for prediction of primary nonresponse to infliximab therapy

BACKGROUND

Primary nonresponse, defined as lack of clinical benefit during the induction phase, occurs in up to 30% of IBD patients treated with infliximab. The mechanisms underlying primary nonresponse have not yet been clearly defined.

AIM

To evaluate the association of early (week 2 and week 6) induction infliximab and anti-infliximab antibody levels with primary nonresponse.

METHODS

A retrospective observational case-control study of inflammatory bowel disease patients treated with infliximab and followed at Sheba Medical Center between 2009 and 2016 was performed. Pre-infusion infliximab and antibodies to infliximab (ATI) levels were measured by our previously described drug-tolerant ELISA assay.

RESULTS

Thirty-five primary nonresponders have been identified and matched with 105 primary responders (1:3 ratios). Both week 2 and week 6 infliximab levels were significantly lower among primary nonresponders compared to responders (week 2, 6: median level 7.2, 2.2 μg/mL vs 13.5, 9.5 μg/mL, P = .0019, P < .0001 respectively). Antibodies to infliximab appeared more frequently (either week 2 or 6, 68% vs 28% prevalence, P = .0004) and at higher levels in nonresponders compared to responders (week 2, 6: median ATI 7.3, 10.8 μg/mL-eq vs 3.8, 4.4 μg/mL-eq, P = .005, P = .008 respectively). Moreover, week 2 infliximab levels <6.8 μg/mL (AUC = 0.68, P = .002, sensitivity 50%, specificity 86%) and antibodies to infliximab levels >4.3 μg/mL-eq (AUC = 0.78, P = .0004, sensitivity 77%, specificity 71%) were predictive of primary nonresponse. Among the other clinical and demographic variables, higher baseline ulcerative colitis clinical score, infliximab monotherapy, prior adalimumab therapy and previous Crohn's disease-related surgeries were also associated with an increased risk of primary nonresponse.

CONCLUSIONS

Infliximab levels below 6.8 μg/mL and antibodies to infliximab levels above 4.3 μg/mL-eq before the second infusion are associated with primary nonresponse, especially among Crohn's disease patients.

Review article: consensus statements on therapeutic drug monitoring of anti-tumour necrosis factor therapy in inflammatory bowel diseases

BACKGROUND

Therapeutic drug monitoring (TDM) in inflammatory bowel disease (IBD) patients receiving anti-tumour necrosis factor (TNF) agents can help optimise outcomes. Consensus statements based on current evidence will help the development of treatment guidelines.

AIM

To develop evidence-based consensus statements for TDM-guided anti-TNF therapy in IBD.

METHODS

A committee of 25 Australian and international experts was assembled. The initial draft statements were produced following a systematic literature search. A modified Delphi technique was used with 3 iterations. Statements were modified according to anonymous voting and feedback at each iteration. Statements with 80% agreement without or with minor reservation were accepted.

RESULTS

22/24 statements met criteria for consensus. For anti-TNF agents, TDM should be performed upon treatment failure, following successful induction, when contemplating a drug holiday and periodically in clinical remission only when results would change management. To achieve clinical remission in luminal IBD, infliximab and adalimumab trough concentrations in the range of 3-8 and 5-12 μg/mL, respectively, were deemed appropriate. The range may differ for different disease phenotypes or treatment endpoints-such as fistulising disease or to achieve mucosal healing. In treatment failure, TDM may identify mechanisms to guide subsequent decision-making. In stable clinical response, TDM-guided dosing may avoid future relapse. Data indicate drug-tolerant anti-drug antibody assays do not offer an advantage over drug-sensitive assays. Further data are required prior to recommending TDM for non-anti-TNF biological agents.

CONCLUSION

Consensus statements support the role of TDM in optimising anti-TNF agents to treat IBD, especially in situations of treatment failure.