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

Optimising infliximab induction dosing to achieve clinical remission in Chinese patients with Crohn's disease

Aims

A strategy based on therapeutic drug monitoring and population pharmacokinetic (popPK) models would likely increase the rate of clinical remission (CR) after infliximab (IFX) induction in patients with Crohn's disease (CD). This study aimed to evaluate the relationship between early IFX levels and antibodies to infliximab (ATI) and CR at week 14 and simulate the probability of attaining the identified exposure target.

Methods

Patients with CD (n = 140) treated with IFX were enrolled to develop the popPK model. Of these, 43 moderate-to-severe patients with CD were followed up at week 14. Simulations were performed on patients with different dosage regimens and covariates.

Results

IFX levels >20.08 μg/mL at week 2, >18.44 μg/mL at week 6, and >3.08 μg/mL at week 14 were linked to CR. A one-compartment model fit the data best. The covariates influencing clearance were fat free mass, albumin and ATI levels. To achieve IFX levels >20.08 μg/mL at week 2, ≥400 mg IFX was predicted to be required in over 50% patients with 45-70 kg and 35-45 g/L albumin, except for patients with 70 kg and 30 g/L albumin.

Conclusion

IFX levels >20.08 μg/mL at week 2 and absence of ATI at week 14 are associated with CR. Optimising IFX induction dosing will be critical to achieve the target of early IFX levels associated with CR.

Reactive Immunomodulator Addition to Infliximab Monotherapy Restores Clinical Response in Inflammatory Bowel Disease: A Meta-Analysis

BACKGROUND AND AIMS

Patients with inflammatory bowel disease (IBD) receiving infliximab (IFX) commonly experience immunogenic loss of response (LOR) by formation of anti-drug antibodies (ADAs). An immunomodulator (IMM) used in combination with initial IFX induction is known to reduce ADA development and improve clinical outcomes. We aimed to assess the impact of reactively adding an IMM to patients on IFX monotherapy.

METHODS

We conducted a retrospective cohort study and systematic review with meta-analysis of patients with IBD demonstrating immunologic LOR, with or without clinical LOR, that had an IMM (azathioprine, 6-mercaptopurine, or methotrexate) reactively added (reactive combination therapy; rCT) to combat elevated ADAs and raise IFX level. Data were extracted for pooled effect size estimation using random-effects models, and ADA and IFX trough levels were compared pre- and post-IMM initiation.

RESULTS

We identified 6 patients who received rCT due to rising ADA titers and low IFX levels. Median ADA titer decreased from 506 ng/mL (interquartile range (IQR) [416-750]) to 76.5 ng/mL (IQR [25.8-232]), an 85% decrease (p = 0.031). Median IFX trough increased from 0.4 µg/mL (IQR [0.4-0.48]) to 8.25 µg/mL (IQR [3.7-9.6]), a 20.6-fold increase (p = 0.038). Meta-analysis pooled effect size of 7 studies with 89 patients showed an 87% ADA titer reduction [95% confidence interval (CI) = 72-94%], 6.7-fold increased IFX trough (95% CI = 2.4-18.7), and 76% clinical remission rescue rate (95% CI = 59-93%).

CONCLUSIONS

These results suggest rCT is a valid rescue strategy in patients with immunogenic LOR to IFX to reduce ADA titers, restore therapeutic IFX levels, and recapture clinical remission of IBD.

Development and validation of a novel therapeutic drug monitoring-based nomogram for prediction of primary endoscopic response to anti-TNF therapy in active Crohn's disease

Background

Anti-tumor necrosis factor (TNF) monoclonal antibodies, especially infliximab (IFX) and adalimumab (ADA), are considered the first-line treatment for active Crohn's disease (CD). However, the predictive role of therapeutic drug monitoring (TDM) of serum anti-TNF in monitoring the treatment of inflammatory bowel disease (IBD) remains controversial.

Objectives

To explore the correlation between serum anti-TNF levels and early endoscopic response in active CD using a TDM-based nomogram.

Design

Cross-sectional study.

Methods

The simplified endoscopic activity score for CD (SES-CD), Crohn's disease activity index (CDAI), laboratory parameters, and the serum trough levels of IFX and ADA were assessed.

Results

The trough levels of IFX or ADA were significantly higher in patients with endoscopic response compared to non-responders in the development cohort (p < 0.001). The IFX and ADA levels showed a weak but significantly negative correlation with SES-CD (p < 0.001), CDAI (p < 0.001), and C-reactive protein (CRP) (p < 0.001) at week 14 post-IFX therapy in the development cohort. Furthermore, the receiver operating characteristic curve revealed that an optimal level of IFX (4.80 μg/mL) and ADA (8.80 μg/mL) exhibited the best performance in predicting endoscopic response. Concomitantly, we developed a novel nomogram prediction model based on the results of multivariate logistic regression analysis, which consisted of CRP, albumin (Alb), and anti-TNF trough levels at week 14. The nomogram showed significant discrimination and calibration for both IFX and ADA in the development cohort and performed well in the external validation cohort.

Conclusion

This study demonstrates a robust association between serum concentrations of IFX, ADA, Alb, and CRP and primary endoscopic response in active CD patients. Importantly, the TDM- and laboratory marker-based nomogram may be used to evaluate the primary endoscopic response to anti-TNF therapy, especially for optimizing treatment strategies and switching therapy in CD patients.

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.

Absolute monocyte counts could predict disease activity and secondary loss of response of patients with Crohn's disease treated with anti-TNF-α drug

BACKGROUND

Assessing Crohn's disease (CD) activity is critical for monitoring disease progression. In CD, monocytes could release TNF-α. Thus, it is extremely important to study its role in the disease activity and loss of response to anti-TNF-α biologics.

METHODS

In this study, we collected CD patients treated with biologics from January 2017 to May 2022. Indicators associated with disease activity were evaluated by Spearman correlation analysis and Mann-Whitney U test. Specifically, logistic analyses were used to explore the predictors of primary nonresponse (PNR) and secondary loss of response (SLOR) within 1 year of anti-TNF-α agents. In addition, a nomogram was developed for therapeutic effect prediction.

RESULTS

283 patients with CD were identified. Disease activity group, defined as CDAI equal to or greater than 150, had significant elevated absolute monocyte counts than disease remission group based on CDAI score (p = 0.019, Z = -2.354). Logistic analyses showed that absolute monocyte counts could be an independent predictor of 1-year SLOR of anti-TNF-α agents in CD patients (p = 0.013). A nomogram established based on gender, absolute monocyte counts, and hemoglobin could predict SLOR within 1 year of anti-TNF-α agents reliably.

CONCLUSION

The results of this study support the utility of absolute monocyte counts detecting disease activity and anti-TNF-α therapy effect in patients with CD.

First Mexican Consensus on Crohn's disease

INTRODUCTION

Crohn's disease (CD) is a subtype of chronic and incurable inflammatory bowel disease. It can affect the entire gastrointestinal tract and its etiology is unknown.

OBJECTIVE

The aim of this consensus was to establish the most relevant aspects related to definitions, diagnosis, follow-up, medical treatment, and surgical treatment of Crohn's disease in Mexico.

MATERIAL AND METHODS

Mexican specialists in the areas of gastroenterology and inflammatory bowel disease were summoned. The consensus was divided into five modules, with 69 statements. Applying the Delphi panel method, the pre-meeting questions were sent to the participants, to be edited and weighted. At the face-to-face meeting, all the selected articles were shown, underlining their level of clinical evidence; all the statements were discussed, and a final vote was carried out, determining the percentage of agreement for each statement.

RESULTS

The first Mexican consensus on Crohn's disease was produced, in which recommendations for definitions, classifications, diagnostic aspects, follow-up, medical treatment, and surgical treatment were established.

CONCLUSIONS

Updated recommendations are provided that focus on definitions, classifications, diagnostic criteria, follow-up, and guidelines for conventional medical treatment, biologic therapy, and small molecule treatment, as well as surgical management.

An in vitro analysis of the interaction between infliximab and granulocyte-monocyte apheresis

OBJECTIVE

Primary non-response and secondary loss of response to anti-TNF agents are common in inflammatory bowel disease. Increasing drug concentrations are correlated to better clinical response and remission rates. Combination of granulocyte-monocyte apheresis (GMA) with anti-tumor necrosis factor (TNF) agents could be an option in these patients. The objective of our study was to perform an in vitro assay to determine if the GMA device can lead to infliximab (IFX) adsorption.

PATIENTS AND METHODS

A blood sample was obtained from a healthy control. It was incubated with three concentrations of IFX (3, 6, and 9μg/ml) at room temperature for 10min. At that time, 1ml was collected to determine the IFX concentration. Then, 10ml of each drug concentration was incubated with 5ml of cellulose acetate (CA) beads from the GMA device at 200rpm for 1h at 37°C to simulate physiological human conditions. A second sample of each concentration was collected and IFX levels were determined.

RESULTS

No statistically significant differences were observed in the IFX levels in the blood samples before and after incubation with the CA beads (p=0.41) and after repeated measurements (p=0.31). Mean change was 3.8μg/ml.

CONCLUSIONS

The in vitro combination of GMA and IFX did not change the circulating levels of IFX at the three concentrations tested, suggesting that there is no interaction between the drug and the apheresis device in vitro and that they might be safely combined with each other.

Is tumor necrosis factor-α monoclonal therapy with proactive therapeutic drug monitoring optimized for inflammatory bowel disease? Network meta-analysis

BACKGROUND

The efficacy and safety of anti-tumor necrosis factor-α (TNF-α) monoclonal antibody therapy [adalimumab (ADA) and infliximab (IFX)] with therapeutic drug monitoring (TDM), which has been proposed for inflammatory bowel disease (IBD) patients, are still controversial.

AIM

To determine the efficacy and safety of anti-TNF-α monoclonal antibody therapy with proactive TDM in patients with IBD and to determine which subtype of IBD patients is most suitable for proactive TDM interventions.

METHODS

As of July 2023, we searched for randomized controlled trials (RCTs) and observational studies in PubMed, Embase, and the Cochrane Library to compare anti-TNF-α monoclonal antibody therapy with proactive TDM with therapy with reactive TDM or empiric therapy. Pairwise and network meta-analyses were used to determine the IBD patient subtype that achieved clinical remission and to determine the need for surgery.

RESULTS

This systematic review and meta-analysis yielded 13 studies after exclusion, and the baseline indicators were balanced. We found a significant increase in the number of patients who achieved clinical remission in the ADA [odds ratio (OR) = 1.416, 95% confidence interval (CI): 1.196-1.676] and RCT (OR = 1.393, 95%CI: 1.182-1.641) subgroups and a significant decrease in the number of patients who needed surgery in the proactive vs reactive (OR = 0.237, 95%CI: 0.101-0.558) and IFX + ADA (OR = 0.137, 95%CI: 0.032-0.588) subgroups, and the overall risk of adverse events was reduced (OR = 0.579, 95%CI: 0.391-0.858) according to the pairwise meta-analysis. Moreover, the network meta-analysis results suggested that patients with IBD treated with ADA (OR = 1.39, 95%CI: 1.19-1.63) were more likely to undergo TDM, especially in comparison with patients with reactive TDM (OR = 1.38, 95%CI: 1.07-1.77).

CONCLUSION

Proactive TDM is more suitable for IBD patients treated with ADA and has obvious advantages over reactive TDM. We recommend proactive TDM in IBD patients who are treated with ADA.

Controversies in the management of anti-TNF therapy in patients with Crohn's disease: a Delphi consensus

BACKGROUND

Despite research, there are still controversial areas in the management of Crohn's disease (CD).

OBJECTIVE

To establish practical recommendations on using anti-tumour necrosis factor (TNF) drugs in patients with moderate-to-severe CD.

METHODS

Clinical controversies in the management of CD using anti-TNF therapies were identified. A comprehensive literature review was performed, and a national survey was launched to examine current clinical practices when using anti-TNF therapies. Their results were discussed by expert gastroenterologists within a nominal group meeting, and a set of statements was proposed and tested in a Delphi process.

RESULTS

Qualitative study. The survey and Delphi process were sent to 244 CD-treating physicians (response rate: 58%). A total of 14 statements were generated. All but two achieved agreement. These statements cover: (1) use of first-line non-anti-TNF biological therapy; (2) role of HLA-DQA1*05 in daily practice; (3) attitudes in primary non-response and loss of response to anti-TNF therapy due to immunogenicity; (4) use of ustekinumab or vedolizumab if a change in action mechanism is warranted; (5) anti-TNF drug level monitoring; (6) combined therapy with an immunomodulator.

CONCLUSION

This document sought to pull together the best evidence, experts' opinions, and treating physicians' attitudes when using anti-TNF therapies in patients with CD.

Impact of proactive therapeutic drug monitoring of infliximab during the induction phase in IBD patients. A Bayesian approach

BACKGROUND AND OBJECTIVES

there is increasing evidence that proactive therapeutic drug monitoring in induction is useful to improve the control of inflammatory bowel disease (IBD), although it remains controversial. The primary objective of the study was to assess the short-term outcomes of proactive Bayesian therapeutic drug monitoring (TDM) during induction, to optimize infliximab (IFX) maintenance dose.

METHODS

retrospective observational cohort of IBD patients > 18 years. They were divided into two cohorts, standard therapy group (ST-group), with clinically based dose adjustment, and monitoring group (iTDM-group), with pharmacokinetic parameters calculated by Bayesian prediction at week 6 and individualized dosage regimens thereafter. In patients with an infliximab trough level (ITL) at week 6 below the optimal therapeutic range, the dose adjustment was performed at the first maintenance dose.

RESULTS

a total of 153 patients were included, 40 in the iTDM-group. Median ITL at week 6 during the induction period was 12.8 µg/ml (IRQ: 12.7) in this group. Only 16 patients (40.0 %) had ITL ≥ 15 µg/ml. Half of the patients (50.3 %) received intensified maintenance therapy during the study period (57.5 % iTDM vs 47.8 % ST, p = 0.291). The proportion of patients achieving primary response at week 14 was 51.8 %. When comparing the two groups, this proportion was higher in the iTDM group (74.3 % vs 44.2 %, p = 0.002). With regards to the variable "poor clinical outcomes" at week 26, this proportion was lower in the iTDM group (3.3 % iTDM vs 21.1 % ST, p = 0.024).

CONCLUSIONS

proactive therapeutic drug monitoring using Bayesian approach is associated with higher primary response rates and fewer short-term complications.

Efficacy of Early Optimization of Infliximab Guided by Therapeutic Drug Monitoring during Induction-A Prospective Trial

Therapeutic drug monitoring (TDM) during induction therapy with anti-tumor necrosis factor drugs has emerged as a strategy to optimize response to these biologics and avoid undesired outcomes related to inadequate drug exposure. This study aimed to describe clinical, biological, and endoscopic remission rates at six months in Brazilian inflammatory bowel disease (IBD) patients following a proactive TDM algorithm guided by IFX trough levels (ITL) and antibodies to IFX (ATI) levels during induction, at week six. A total of 111 IBD patients were prospectively enrolled, excluding those previously exposed to the drug. ITL ≥ 10 μg/mL was considered optimal. Patients with suboptimal ITL (<10 µg/mL) were guided according to ATI levels. Those who presented ATI ≤ 200 ng/mL underwent dose intensification in the maintenance phase, and patients with ATI > 200 ng/mL discontinued IFX. In our study, proactive TDM was associated with persistence in the IFX rate at six months of 82.9%. At that time, rates of clinical, biological, and endoscopic remission in patients under IFX treatment were 80.2%, 73.9%, and 48.1%, respectively. Applying a simplified TDM-guided algorithm during induction seems feasible and can help improve patients' outcomes in clinical practice.

Recent Advances in the Optimization of Anti-TNF Treatment in Patients with Inflammatory Bowel Disease

Despite the evolution in inflammatory bowel disease (IBD) management during the last 20 years owing to the advent of new advanced therapies, anti-TNF agents still remain the cornerstone of therapy for both Crohn's disease and ulcerative colitis. However, this does not only secure favorable outcomes for patients considering the progressive disease character and the high likelihood of primary or secondary loss of response. Therefore, trying to reach a better treatment approach and maximize the benefits anti-TNF agents offer, optimization strategies should be examined. It has been indicated that optimizing treatment with anti-TNF enhances drug efficacy and has been associated with improved disease outcomes and a complication-free disease course. From this perspective, we aim to provide an overview of currently available data and recent advances in the practices of anti-TNF treatment optimization. Special focus has been given to the role of therapeutic drug monitoring (TDM), as well as the utility of combining anti-TNF with an immunomodulator and the treat-to-target approach.

GADECCU 2022 Guideline for the treatment of Ulcerative Colitis. Adaptation and updating of the GETECCU 2020 Guideline

INTRODUCTION

Ulcerative colitis (UC) is a chronic inflammatory disease that compromises the colon, affecting the quality of life of individuals of any age. In practice, there is a wide spectrum of clinical situations. The advances made in the physio pathogenesis of UC have allowed the development of new, more effective and safer therapeutic agents.

OBJECTIVES

To update and expand the evaluation of the efficacy and safety of relevant treatments for remission induction and maintenance after a mild, moderate or severe flare of UC.

RECIPIENTS

Gastroenterologists, coloproctologists, general practitioners, family physicians and others health professionals, interested in the treatment of UC.

METHODOLOGY

GADECCU authorities obtained authorization from GETECCU to adapt and update the GETECCU 2020 Guide for the treatment of UC. Prepared with GRADE methodology. A team was formed that included authors, a panel of experts, a nurse and a patient, methodological experts, and external reviewers. GRADE methodology was used with the new information.

RESULTS

A 118-page document was prepared with the 44 GADECCU 2022 recommendations, for different clinical situations and therapeutic options, according to levels of evidence. A section was added with the new molecules that are about to be available.

CONCLUSIONS

This guideline has been made in order to facilitate decision-making regarding the treatment of UC, adapting and updating the guide prepared by GETECCU in the year 2020.

90K/Mac-2 BP Is a New Predictive Biomarker of Response to Infliximab Therapy in IBD Patients

Inflammatory bowel diseases (IBD), comprising Crohn's disease (CD) and Ulcerative Colitis (UC), are multifactorial disorders characterized by a chronic inflammatory status with the secretion of cytokines and immune mediators. Biologic drugs targeting pro-inflammatory cytokines, such as infliximab, are broadly used in the treatment of IBD patients, but some patients lose responsiveness after an initial success. The research into new biomarkers is crucial for advancing personalized therapies and monitoring the response to biologics. The aim of this single center, observational study is to analyze the relationship between serum levels of 90K/Mac-2 BP and the response to infliximab, in a cohort of 48 IBD patients (30 CD and 18 UC), enrolled from February 2017 to December 2018. In our IBD cohort, high 90K serum levels were found at baseline in patients who then developed anti-infliximab antibodies at the fifth infusion (22 weeks after the first), becoming non-responders (9.76 ± 4.65 µg/mL compared to 6.53 ± 3.29 µg/mL in responder patients, p = 0.005). This difference was significant in the total cohort and in CD, but not significant in UC. We then analyzed the relationship between serum levels of 90K, C-reactive protein (CRP), and Fecal calprotectin. A significant positive correlation was found at baseline between 90K and CRP, the most common serum inflammation marker (R = 0.42, p = 0.0032). We concluded that circulating 90K could be considered a new non-invasive biomarker for monitoring the response to infliximab. Furthermore, 90K serum level determination, before the first infliximab infusion, in association with other inflammatory markers such as CRP, could assist in the choice of biologics for the treatment of IBD patients, thereby obviating the need for a drug switch due to loss of response, and so improving clinical practice and patient care.

Definition of a therapeutic range for predicting long-term infliximab response in patients with inflammatory bowel disease

INTRODUCTION

Monitoring plasma levels of Infliximab plays an important role in optimising treatment in patients with inflammatory bowel disease (IBD). The aim of the following study has been to determine the predictive potential of monitoring infliximab plasma levels for sustained clinical response and evaluate its usefulness to improve treatment efficacy and symptom control, in patients with IBD.

METHODS

This single-centre retrospective study (2017-2019) included patients diagnosed with IBD treated with infliximab. Serum levels and the occurrence of drug-associated immunogenicity were analysed at Week 8 post-induction and 6, 12 and 24 months. Clinical parameters and inflammatory markers were recorded such as subjective global assessment (SGA), C-reactive protein (CRP) and faecal calprotectin (FC). Factors associated with early discontinuation and dose intensification of infliximab were determined.

RESULTS

Multivariate analysis determined that IFX concentrations>7μg/mL at week 8, and at 6 months, are associated with inflammatory remission (p=0.046, 0.045). IFX>7μg/mL at 12 months predicted remission at 18 months of treatment (p=0.006). IFX values>3μg/mL at 12 months are associated with stable SGA at 18 months (p=0.001). Such values at 18 months are associated with stable SGA at 24 months (p=0.044).

CONCLUSIONS AND RELEVANCE

The predictive potential of monitoring IFX plasma levels as a strategy to evaluate sustained long-term clinical response was confirmed. Our results highlight the importance of its introduction into routine clinical practice to enable early identification of non-responders, treatment optimisation, relapse prevention and improve long-term therapy maintenance.

Dose intensification strategy influences infliximab pharmacokinetics but not clinical response after the same number of doses

BACKGROUND

The optimal infliximab dose intensification strategy to address secondary loss of response (LOR) remains unclear. This study aimed to compare clinical and pharmacokinetic outcomes following (i) upfront infliximab re-induction with (ii) ongoing 6-weekly dose interval shortening (DIS), after the same number of doses.

METHODS

A prospective parallel cohort study of inflammatory bowel disease patients who required infliximab dose intensification for secondary LOR using (i) re-induction (i.e., repeat 5 mg/kg 0, 2, 6-week dosing) followed by 8-weekly maintenance or (ii) 6-weekly 5 mg/kg DIS was undertaken. Week 32 clinical response was the primary outcome, with secondary evaluation of infliximab pharmacokinetics and predictors of response.

RESULTS

Of 104 patients, 54 underwent re-induction, and 50 underwent 6-weekly DIS; 43 per cohort had clinically active disease, with comparable baseline infliximab levels (2.03 vs 2.02 ug/mL, P = 0.83). Clinical response was similar across re-induction and DIS cohorts at weeks 12 (69.8 vs 65.1%) and 32 (53.5 vs 62.8%, each P > 0.50); however, both strategies demonstrated distinct pharmacokinetic profiles at weeks 6 (18.45 vs 5.36 ug/mL, P < 0.01), 12 (8.94 vs 5.96 ug/mL, P = 0.02) and 30 (3.89 vs 6.35 ug/mL, P = .0.02). In multivariable analyses, objectively verified active disease at baseline (OR 12.92, 95% CI [1.84-90.84], P = 0.01), subtherapeutic week 6 infliximab levels (OR 0.12, 95% CI [0.01, 0.99], P = 0.049) and week 12 clinical response (OR 5.44, 95% CI [1.20-19.97], P = 0.04) were associated with week 32 response, as were week 2 infliximab levels (OR 1.34, 95% CI [1.02-1.47], P = 0.04) following re-induction. Following re-induction, week 2 infliximab levels <15.6 ug/mL (AUROC 0.76, 95% CI [0.54-0.99], P < 0.05) predicted nonresponse at week 32.

CONCLUSION

Dose intensification strategy impacted immediate and sustained infliximab levels but not clinical response. Upfront intensification was associated with short-term pharmacokinetic advantages, including predictors of response, that diminished with time. Hence, when applying upfront dose intensification, clinicians should consider continuing intensified dosing to sustain early pharmacokinetic advantages based on predictors of (non)response.

A Systematic Review on the interest of Drug Tolerant assay in the monitoring of Inflammatory Bowel Disease

Many patients with inflammatory bowel disease (IBD) are treated with anti-tumor necrosis factor (TNF) therapies, of which infliximab (IFX) is most commonly used. Loss of response (LOR) to anti-TNF therapy due to immunogenic failure accounts for 20% of subsequent medical intervention and is defined, using a drug sensitive assay, as low or undetectable concentration of drug with high titers of anti-drug antibodies (ADAb). We performed a systematic review to investigate the use of a drug tolerant assay during both induction and maintenance to monitor patients treated with anti-TNFs. After the search on PubMed, 90 publications were reviewed. Most ADAb detection methods are drug sensitive, cannot detect ADAb in the presence of drug, and therefore cannot be used close to drug administration, when the drug concentration is too high. To overcome this major limitation, several drug-tolerant techniques have been developed and will be discussed in this review. Using drug-tolerant assays ADAb against infliximab (IFX) or adalimumab (ADM) can be detected during induction and predict primary non-response or LOR. Drug sensitive assays do not allow detection of ADAb during the induction phase as IFX or ADM concentration is typically high.

Proactive infliximab is more effective than vedolizumab in inducing fecal calprotectin remission in inflammatory bowel disease

BACKGROUND

Current evidence suggests vedolizumab (VDZ) may be as effective as Infliximab (IFX) in inflammatory bowel disease. It is unknown if proactive therapeutic drug monitoring (PTDM) of IFX may improve these results.

METHODS

Case-control study including consecutive patients with primary response to conventional IFX (n = 70), proactive IFX (n = 148), and VDZ (n = 95). PTDM was performed at week 14 and every other infusion, aiming at a trough level between 5 and 10 µg/ml. The primary outcome was fecal calprotectin (Fc) remission (<250 µg/g) at 1 year of treatment. Secondary outcomes included Fc remission at week 14 (proactive IFX/VDZ), clinical remission, treatment discontinuation, hospitalization, and surgery at 1-year of follow-up.

RESULTS

Proactive IFX was superior to conventional IFX and VDZ in inducing Fc remission at 1-year (69.4% vs 47.1% vs 37.9%, p = .003 and p < .001). Results remained significant in biologic naïve patients (70.8% vs 44.4% vs 51.4%, p = .001 and p = .043) but comparisons between conventional IFX and VDZ were not significant (p = .265 and p = .664). In multivariate analysis correcting for prior biologic exposure, proactive IFX was more effective than conventional IFX (OR 2.480 95%CI [1.367-4.499], p = .003) and VDZ (OR 3.467 95%CI [1.578-7.617], p = .002) in inducing Fc remission. Amongst secondary outcomes, only clinical remission was significant between proactive IFX and VDZ in the overall cohort (80.4% vs 55.8%, p < .001) and in biologic naïve patients (80.2% vs 62.9%, p = .043). Fc remission at 1-year was associated with better results in most secondary outcomes.

CONCLUSION

Proactive IFX was superior to VDZ in inducing Fc remission at 1-year, which was associated with improved clinical outcomes.SUMMARYCurrent evidence suggests that vedolizumab may be as effective as Infliximab in the treatment of patients with inflammatory bowel disease.There have been no studies comparing vedolizumab with proactively optimized Infliximab based on trough levels.We confirm that conventional IFX is as effective as vedolizumab but proactive IFX appears superior to vedolizumab in inducing fecal calprotectin remission.Fecal calprotectin remission associates with better clinical outcomes.

Anti-infliximab antibodies and clinical response in noninfectious uveitis and scleritis patients treated with infliximab: A retrospective review

Purpose

To investigate the clinical response to infliximab in ocular inflammation patients who develop anti-infliximab antibodies (AIA) vs. those patients who do not develop AIA.

Observations

A retrospective review was performed of patients treated with infliximab for noninfectious uveitis (NIU) or scleritis. Clinical response was determined as a composite clinical endpoint and classified as complete, partial, or absent. Nine of 32 infliximab-treated patients (28%) were found to develop AIA. Among the AIA-positive patients, clinical response was complete in 7 patients (78%) and partial in 2 patients (22%). Among the AIA-negative patients, clinical response was complete in 15 patients (65%), partial in 6 patients (26%) and absent in 2 patients (9%). Serum infliximab levels tended to decrease with appearance of AIA but rarely became undetectable.

Conclusions and Importance

In this pilot study, AIA-positive patients did not have diminished clinical response to infliximab when compared with AIA-negative patients. There was a high rate of complete clinical response to infliximab in this group of NIU and scleritis patients. Approximately a quarter of patients developed AIA. AIA-positive patients did not have diminished rates of clinical response when compared with AIA-negative patients. This suggests that routine AIA monitoring may not be clinically useful, although validation of this finding in larger cohorts is necessary.

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.

Lymphocyte-to-monocyte ratio is a short-term predictive marker of ulcerative colitis after induction of advanced therapy

Advanced therapies for patients with mild-to-severe ulcerative colitis (UC) may result in treatment failure. We examined whether the lymphocyte-to-monocyte ratio (L/M ratio) could predict the failure of advanced therapies. This retrospective, observational, cohort study included 73 patients who were treated with advanced therapies at the Hamamatsu University School of Medicine (Shizuoka, Japan) between February 2011 and November 2020. The patients were divided into the non-failure and failure groups, and their leukocyte counts and ratios before induction were examined. Univariate and multivariate analyses were performed to identify the prognostic factors. Advanced therapies failed within 3 months in 15 (20.5%) patients. Only the L/M ratio was significantly lower in the failure group than in the non-failure group (P = 0.004). Receiver-operating characteristic (ROC) curve analysis revealed that an L/M ratio of ≤3.417 was predictive of treatment failure; the area under the curve (AUC) was 0.747 (95% CI, 0.620–0.874). Kaplan–Meier analysis revealed that the failure-free rate was significantly lower in the group with an L/M ratio of ≤3.417 than in the group with an L/M ratio of >3.417 (log-rank test P = 0.002). Cox proportional hazard regression analysis identified an L/M ratio of ≤3.417 as an independent risk factor for failure within 3 months after the induction of advanced therapies. Furthermore, ROC analysis of patients who did not receive immunomodulators also revealed that the cut-off L/M ratio was 3.417 and the AUC was 0.796 (95% CI, 0.666–0.925). In patients receiving advanced therapies for active UC, the L/M ratio can predict treatment failure within 3 months. L/M ratios could facilitate the transition from advanced therapies to subsequent treatments.

Alterations and Potential Applications of Gut Microbiota in Biological Therapy for Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is a chronic immune-mediated inflammatory disorder of the gastrointestinal tract that is closely associated with dysbiosis of the intestinal microbiota. Currently, biologic agents are the mainstream therapies for IBD. With the increasing incidence of IBD, limitations of biologic agents have gradually emerged during treatment. Recent studies have indicated that gut microbiota is highly correlated with the efficacy of biologic agents. This review focuses on alterations in both the components and metabolites of gut microbiota during biological therapy for IBD, systematically summarises the specific gut microbiota closely related to the clinical efficacy, and compares current predictive models for the efficacy of biologics, further highlighting the predictive value of intestinal microbiota. Based on the mechanistic analysis of faecal microbiota transplantation (FMT) and biologic agents, a new therapeutic strategy, comprising a combination of FMT and biologics, has been proposed as a promising treatment for IBD with improved efficacy.

Therapeutic drug monitoring in inflammatory bowel disease treatments

Recently, biological drugs have played a leading role in the treatment of inflammatory bowel disease, and therapeutic drug monitoring (TDM) may be useful in maximizing their effectiveness. TDM involves the measurement of serum drug and anti-drug antibodies concentrations as the basis for dosage adjustments or drug conversions to achieve a higher response rate. We believe that concentration thresholds should be individualized based on patients’ disease severity, extent and phenotype, and therapeutic purposes should also be considered, with higher cut-offs mainly needed for endoscopic and fistula healing than for symptomatic remission. Proactive and reactive TDM can help optimize treatment, especially in patients receiving anti-tumour necrosis factor, and guide dose adjustment or drug conversion with lower cost. TDM is a promising approach to achieve precision medicine and targeted medicine in the future.

Antibiotic use differentially affects the risk of anti-drug antibody formation during anti-TNFα therapy in inflammatory bowel disease patients: a report from the epi-IIRN

OBJECTIVE

Anti-drug antibodies (ADA) to anti-tumour necrosis factor (anti-TNF) therapy drive treatment loss of response. An association between intestinal microbial composition and response to anti-TNF therapy was noted. We therefore aimed to assess the implications of antibiotic treatments on ADA formation in patients with inflammatory bowel disease (IBD).

DESIGN

We analysed data from the epi-IIRN (epidemiology group of the Israeli IBD research nucleus), a nationwide registry of all patients with IBD in Israel. We included all patients treated with anti-TNF who had available ADA levels. Survival analysis with drug use as time varying covariates were used to assess the association between antibiotic use and ADA development. Next, specific pathogen and germ-free C57BL mice were treated with respective antibiotics and challenged with infliximab. ADA were assessed after 14 days.

RESULTS

Among 1946 eligible patients, with a median follow-up of 651 days from initiation of therapy, 363 had positive ADA. Cox proportional hazard model demonstrated an increased risk of ADA development in patients who used cephalosporins (HR=1.97, 95% CI 1.58 to 2.44), or penicillins with β-lactamase inhibitors (penicillin-BLI, HR=1.4, 95% CI 1.13 to 1.74), whereas a reduced risk was noted in patients treated with macrolides (HR=0.38, 95% CI 0.16 to 0.86) or fluoroquinolones (HR=0.20, 95% CI 0.12 to 0.35). In mice exposed to infliximab, significantly increased ADA production was observed in cephalosporin as compared with macrolide pretreated mice. Germ-free mice produced no ADA.

CONCLUSION

ADA production is associated with the microbial composition. The risk of ADA development during anti-TNF therapy can possibly be reduced by avoidance of cephalosporins and penicillin-BLIs, or by treatment with fluoroquinolones or macrolides.

Collecting New Peak and Intermediate Infliximab Levels to Predict Remission in Inflammatory Bowel Diseases

BACKGROUND

The loss of response to infliximab is a challenge for clinicians in the management of inflammatory bowel disease (IBD). Mounting evidence suggests that therapeutic drug monitoring at induction may predict remission during maintenance. The aim of the study was to improve predictive models of remission by exploring new peak and intermediate infliximab measurements during induction.

METHODS

This was a prospective multicenter study evaluating the pharmacokinetics of infliximab during induction in a pioneer cohort of 63 patients with IBD. Pharmacokinetics data including peak, intermediate, and trough levels were combined with clinical and biological parameters and were subsequently fed into tailored logistic regression and tree-based techniques to predict remission at week 30.

RESULTS

Infliximab peak levels at week 2, intermediate levels at week 3, and trough levels at week 6 were correlated with remission at week 30. Predictive models exhibited an increased accuracy over the successive timepoints of the induction with key inputs such as albumin, C-reactive protein, eosinophils, neutrophils, lymphocytes, intermediate level at week 3, trough level at week 6, and age at diagnosis. Our predictive model of remission at week 30 was obtained with an area under the receiver operating characteristic curve of 0.9 ± 0.12, a sensitivity of 89%, and a specificity of 75%.

CONCLUSIONS

This study showed the clinical relevance of measuring new infliximab levels to predict remission in patients with IBD. These findings lay the foundation for a personalized medicine in which biotherapies could be monitored at an early stage, thereby improving patients' clinical management.

Comparison of Timing to Develop Anti-Drug Antibodies to Infliximab and Adalimumab Between Adult and Pediatric Age Groups, Males and Females

OBJECTIVE

To compare the timing of serum anti-drug antibodies in adult and pediatric age groups, males and females, treated for inflammatory bowel disease or arthritis with adalimumab or infliximab by retrospectively combining data collected during a 2-year therapeutic drug monitoring period.

METHODS

Four hundred thirty sera were divided in groups collected at 0, 3, 6, 12, and 24 months (T0, T3, T6, T12, and T24) after initiation of therapy and assayed for drug and relative anti-drug antibodies levels. At each time point, the percentage of sera presenting anti-drug antibodies, as well as the drug concentrations, were calculated and correlated with patient age and sex.

RESULTS

Anti-drug antibodies were present in 31.5% of sera and were significantly higher in the pediatric age group than in the adult age group, through all time points. The percentages of sera showing anti-drug antibodies were significantly different as early as 3 months and were sera from pediatric female group. The percentages of sera showing anti-drug antibodies reached the highest value at 6 months in the pediatric age group and at 12 months in the adult age group.

CONCLUSIONS

Sera from pediatric had an earlier presence of anti-drug antibodies than adults. In particular, pediatric females sera showed the fastest anti-drug antibodies development.

Genetic association of primary nonresponse to anti-TNFα therapy in patients with inflammatory bowel disease

OBJECTIVES

Primary nonresponse (PNR) to antitumor necrosis factor-α (TNFα) biologics is a serious concern in patients with inflammatory bowel disease (IBD). We aimed to identify the genetic variants associated with PNR.

PATIENTS AND METHODS

Patients were recruited from outpatient GI clinics and PNR was determined using both clinical and endoscopic findings. A case-control genome-wide association study was performed in 589 IBD patients and associations were replicated in an independent cohort of 293 patients. Effect of the associated variant on gene expression and TNFα secretion was assessed by cell-based assays. Pleiotropic effects were investigated by Phenome-wide association study (PheWAS).

RESULTS

We identified rs34767465 as associated with PNR to anti-TNFα therapy (odds ratio: 2.07, 95% CI, 1.46-2.94, P = 2.43 × 10-7, [replication odds ratio: 1.8, 95% CI, 1.04-3.16, P = 0.03]). rs34767465 is a multiple-tissue expression quantitative trait loci for FAM114A2. Using RNA-sequencing and protein quantification from HapMap lymphoblastoid cell lines (LCLs), we found a significant decrease in FAM114A2 mRNA and protein expression in both heterozygous and homozygous genotypes when compared to wild type LCLs. TNFα secretion was significantly higher in THP-1 cells [differentiated into macrophages] with FAM114A2 knockdown versus controls. Immunoblotting experiments showed that depletion of FAM114A2 impaired autophagy-related pathway genes suggesting autophagy-mediated TNFα secretion as a potential mechanism. PheWAS showed rs34767465 was associated with comorbid conditions found in IBD patients (derangement of joints [P = 3.7 × 10-4], pigmentary iris degeneration [P = 5.9 × 10-4], diverticulum of esophagus [P = 7 × 10-4]).

CONCLUSIONS

We identified a variant rs34767465 associated with PNR to anti-TNFα biologics, which increases TNFα secretion through mechanism related to autophagy. rs34767465 may also explain the comorbidities associated with IBD.

Novel Gene Signatures Predicting Primary Non-response to Infliximab in Ulcerative Colitis: Development and Validation Combining Random Forest With Artificial Neural Network

Background: While infliximab has revolutionized the treatment of ulcerative colitis, primary non-response is difficult to predict, which limits effective disease management. The study aimed to establish a novel genetic model to predict primary non-response to infliximab in patients with ulcerative colitis.

Methods: Publicly available mucosal expression profiles of infliximab-treated ulcerative colitis patients (GSE16879, GSE12251) were utilized to identify potential predictive gene panels. The random forest algorithm and artificial neural network were applied to further screen for predictive signatures and establish a model to predict primary non-response to infliximab.

Results: A total of 28 downregulated and 2 upregulated differentially expressed genes were identified as predictors. The novel model was successfully established on the basis of the molecular prognostic score system, with a significantly predictive value (AUC = 0.93), and was validated with an independent dataset GSE23597 (AUC = 0.81).

Conclusion: Machine learning was used to construct a predictive model based on the molecular prognostic score system. The novel model can predict primary non-response to infliximab in patients with ulcerative colitis, which aids in clinical-decision making.

A random forest model predicts responses to infliximab in Crohn's disease based on clinical and serological parameters

BACKGROUND

Infliximab (IFX) has revolutionised the treatment for Crohn's disease (CD) recently, while a part of patients show no response to it at the end of the induction period. We developed a random forest-based prediction tool to predict the response to IFX in CD patients.

METHODS

This observational study retrospectively enrolled the patients diagnosed with active CD and received IFX treatment at the Gastroenterology Department in Xiangya Hospital of Central South University between January 2017 and December 2019. The baseline data were recorded in the beginning and were used as predictor variables to construct models to forecast the outcome of the response to IFX.

RESULTS

Our cohort identified a total of 174 patients finally with a response rate of 29.3% (51/174). The area under the receiver operating characteristic curve (AUC) for the model, based on the random forest was 0.90 (95%CI: 0.82-0.98), compared to the logistic regression model with AUC of 0.68 (95%CI: 0.52-0.85). The optimal cut-off value of the random forest model was 0.34 with the specificity of 0.94, the sensitivity of 0.81 and the accuracy of 0.85. We demonstrated a strong association of IFX response with the levels of complement C3 (C3), high density lipoprotein, serum albumin, Controlling Nutritional Status (CONUT) score and visceral fat area/subcutaneous fat area ratio (VSR).

CONCLUSION

A novel random forest model using the clinical and serological parameters of baseline data was established to identify CD patients with baseline inflammation to achieve IFX response. This model could be valuable for physicians, patients and insurers, which allows individualised therapy.

A Novel Model Based on Serum Biomarkers to Predict Primary Non-Response to Infliximab in Crohn's Disease

Background

Infliximab is effective in inducing and maintaining remission in patients with Crohn's disease (CD), but primary non-response (PNR) occurs in 10-30% of cases. We investigated whether serum biomarkers are effective in predicting PNR in patients with CD.

Methods

From January 2016 to April 2020, a total of 260 patients were recruited to this prospective and retrospective cohort study. Serum samples were collected at baseline and week 2 of infliximab treatment. Serum levels of 35 cytokines were assessed in 18 patients from the discovery cohort and were further evaluated in the 60-patient cohort 1. Then, candidate cytokines and other serological biomarkers were used to construct a predictive model by logistic regression in a 182-patient cohort 2. PNR was defined based on the change of CD activity index or clinical symptoms.

Results

Among the 35 cytokines, matrix metalloproteinase 3(MMP3) and C-C motif ligand 2 (CCL2) were two effective serum biomarkers associated with PNR in both the discovery cohort and cohort 1. In cohort 2, serum level of MMP3, CCL2 and C-reactive protein (CRP) at 2 weeks after infliximab injection were independent predictors of PNR, with odds ratios (95% confidence interval) of 1.108(1.059-1.159), 0.940(0.920-0.965) and 1.102(1.031-1.117), respectively. A PNR classifier combining these three indicators had a large area under the curve [0.896(95% CI:0.895-0.897)] and negative predictive value [0.918(95%CI:0.917-0.919)] to predict PNR to infliximab.

Conclusions

MMP3, CCL2, and CRP are promising biomarkers in prediction of PNR to infliximab, and PNR classifier could accurately predict PNR and may be useful in clinical practice for therapy selection.

GETECCU 2020 guidelines for the treatment of ulcerative colitis. Developed using the GRADE approach

INTRODUCTION

Since the first edition of the Guidelines was published in 2013, much information has been generated around the treatment of ulcerative colitis, and new drugs and action protocols have been introduced. Clinical practice has changed substantially, warranting new approaches and a comprehensive review and update of the evidence.

MATERIAL AND METHODS

Once again, we used the GRADE approach, supported by an electronic tool (https://gradepro.org). The clinical scenarios are the same as in the previous version (induction and maintenance in severe and mild-moderate flare-ups), as are the variables and their evaluation. However, in the updated guidelines, three questions have been deleted, 14 added and 30 maintained, making a total of 44 clinical questions. After an exhaustive review of the evidence, the recommendations are now updated.

RESULTS

Of the 44 questions analysed, no recommendation could be established in two due to the very low quality of the evidence, while in the other 42, based on different degrees of quality of evidence, recommendations were made according to the GRADE system. In 25 of these questions the final recommendation is strongly in favour, in six strongly against, in seven weakly in favour and in four weakly against. According to the scenarios and recommendations, six algorithms are proposed as a simple guide for practical decision-making.

CONCLUSIONS

The aim of this update of the 2013 guidelines is to provide answers, based on the GRADE approach, to the different questions we ask ourselves daily when deciding the most appropriate treatment for our patients with ulcerative colitis in the different clinical scenarios.

Development and Validation of an Interleukin-6 Nomogram to Predict Primary Non-response to Infliximab in Crohn's Disease Patients

Background: The primary non-response (PNR) rate of infliximab (IFX) varies from 20 to 46% for the treatment of Crohn’s disease (CD). Detected PNR reduces the improper use of specific treatments. To date, there is hardly any knowledge regarding early markers of PNR. The aim of this study was to evaluate the role of Interleukin-6 (IL-6) as an early predictor of PNR of IFX for the treatment of CD.

Methods: We enrolled 322 bio-naïve patients diagnosed with CD from January 2016 to May 2020. Primary response was determined at week 14. Multivariable logistic regression was used to construct prediction models. Area under the curve (AUC), calibration and decision curve analyses (DCA) were assessed in the validation cohort. GEO data were analyzed to identify potential mechanisms of IL-6 in IFX therapy for CD.

Results: PNR occurred in 31.06% (100 of 322) patients who were assessable at week 14. IL-6 levels significantly decreased after IFX therapy (p < 0.001). The validation model containing IL-6 presented enhanced discrimination with an AUC of 0.908 and high calibration. Decision curve analysis (DCA) indicated that the model added extra predictive value. GEO data confirmed the IL-6 levels were increased in the PNR group and IL-6-related differentially expressed genes (DEGs) were enriched in the inflammatory response.

Conclusions: We concluded that IL-6 may be used as a predictive factor to assess the risk of PNR to IFX therapy.

Association between ustekinumab trough concentrations and biochemical outcomes in patients with Crohn's disease. A real life study

INTRODUCTION

numerous studies have shown a positive correlation between serum biologic drug concentrations and favorable therapeutic outcomes during the induction and maintenance period in patients with Crohn's disease (CD). To our knowledge, only a few and contradictory studies have determined the association between ustekinumab (UST) trough concentrations and biological outcomes. This study aimed to investigate the relationship between ustekinumab trough concentrations and biological outcomes in a real-world setting.

METHODS

a cross-sectional cohort study was performed. All adult patients with CD who received maintenance therapy (≥ 24 weeks) with ustekinumab were included in the study. Clinical response was determined using the Harvey-Bradshaw Index. Biochemical remission was defined as a fecal calprotectin level < 150 µg/g in feces and a biochemical response as > 50 % reduction of fecal calprotectin.

RESULTS

a total of 58 CD patients were included in the study and the median UST trough concentration was 1.78 µg/ml (IQR: 2.56). Differences in ustekinumab trough concentrations were observed for clinical (2.25 µg/ml vs 0.65 µg/ml; p = 0.006) and biochemical remission (2.33 µg/ml vs 1.03 µg/ml; p = 0.047). According to ROC analysis, a cut-off of 1.4 µg/ml (AUC: 077) and 2.0 µg/ml (AUC: 0.65) were identified for predicting clinical and biochemical remission, respectively. Likewise, ustekinumab trough levels were also higher in "composite clinical/biochemical remission" (2.38 µg/ml vs 1.08 µg/ml; p = 0.042). The trough level that was best associated with composite clinical/biochemical remission was 2.2 µg/ml (AUC: 0.69).

CONCLUSION

this real-life study shows the association between ustekinumab trough concentration and clinical and biochemical remission and we suggest an optimal cut-off point higher than 2.2 µg/ml. Further studies are needed to confirm the findings and to identify the optimal cut-off in different disease outcomes and disease phenotypes.

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.

Infliximab concentrations in two non-switching cohorts of patients with inflammatory bowel disease: originator vs. biosimilar

Biosimilars are replacing originator compounds due to their similar effectiveness, safety and pharmacokinetics. Our objective was to compare the differences in pharmacokinetics and clinical outcomes between the originator infliximab (Ifx) and the biosimilar CT-P13 in a patient cohort with inflammatory bowel disease (IBD). Our cohort study included 86 patients from a historical and a prospective cohort from the start of infliximab treatment to 22 weeks later. Serum infliximab, antidrug antibody levels and other serum biomarkers were measured at weeks 0, 2, 6, 14 and 22. Remission outcomes were evaluated at weeks 14 and 22. Drug levels were measured prospectively and analysed using MANOVA. Of the 86 patients, 44 (51%) and 42 (49%) were administered the originator and CT-P13, respectively. Originator trough levels were higher than the biosimilar trough levels (35 vs. 21, 20.1 vs. 11, 6.6 vs. 2.9 and 4.3 vs. 1.7 μg/mL at weeks 2, 6, 14 and 22, respectively). A post-hoc analysis demonstrated changes in mean serum drug levels over time (p < 0.001) and according to the drug employed (p = 0.001). At week 22, 13 (81%) patients administered the originator achieved clinical remission compared with 5 (19%) patients with the biosimilar (p = 0.02). None of the patients administered the originator withdrew from the treatment compared with 7 for the biosimilar. During the study, there were significant differences in serum infliximab levels between the originator and the CT-P13 in the patients with IBD. The clinical outcomes were influenced by the type of compound administered.

INDUCTION THERAPEUTIC DRUG MONITORING REGIMEN WITH INFLIXIMAB: A SIMPLIFIED EVIDENCE-BASED ALGORITHM FOR INFLAMMATORY BOWEL DISEASE

Therapeutic drug monitoring (TDM) of infliximab (IFX) has been recognized as an important strategy in the management of secondary loss of response to this agent, guiding clinical decision-making in the management of inflammatory bowel diseases (IBD). Although most of the data on the application of TDM for IFX refer to the maintenance phase of treatment, many studies have associated higher drug concentrations, specially in the induction phase, with achievement of important treatment targets, such as clinical remission and mucosal healing. This brief communication aims to summarize the literature on the use of TDM during induction phase of IFX and propose application of a simplified approach which can be useful into clinical practice, aiming better outcomes to IBD patients.

Optimization of biologics to reduce treatment failure in inflammatory bowel diseases

Moderate to severe inflammatory bowel disease patients can fail to respond to conventional therapy and/or to biologic treatment. In the era of TNFα antagonists and other non-anti-TNF biologic drugs, it is important to review the literature on biologic treatment failure, which could be defined as primary non-response, secondary loss of response and intolerance. Therapeutic drug monitoring (TDM), that is, drug trough level and antidrug antibodies, should enable to determine the mechanisms of treatment failure and to optimize drug efficacy. There is a consensus on reactive TDM at the time of loss of response. Proactive TDM could be of interest during induction and/or maintenance, but randomized controlled trials are required.

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.

Therapeutic thresholds and mechanisms for primary non-response to infliximab in inflammatory bowel disease

BACKGROUND

Primary non-response to infliximab (IFX) inherits a poor prognosis in inflammatory bowel disease (IBD). We explored underlying mechanisms and therapeutic thresholds in an effort to provide basis for optimizing therapy.

METHODS

A prospectively followed cohort of 166 IBD patients having received standard IFX induction therapy (5 mg/kg at weeks 2, 6, and 14) had trough IFX and anti-IFX antibodies (Abs) retrospectively assessed at weeks 2 (n = 148) and 6 (n = 108). Circulating TNFα was measured in matched primary non-responders (n = 29) and responders (n = 21) at baseline and weeks 6 and 14. Clinical outcome at week 14 was supported by disease activity scores in half of patients.

RESULTS

In all, 18 patients (11%) had primary non-response. Infliximab was consistently lower throughout the induction phase in non-responders as compared to responders (Week 2: IFX median 18.9 μg/mL vs. 23.3, p < .05. Week 6: 8.4 vs. 17.0, p < .05). Optimal IFX thresholds associated with response was 22.9 μg/mL at week 2 (sensitivity 51%, specificity 80%, AUC_ROC 0.67, p < .05) and 11.8 at week 6 (72%, 77%, 0.71, p < .05). Anti-IFX Abs occurred in 28% of primary non-responders and associated with low IFX and treatment failure (OR 13.7 [2.8-67.5], p < .01). Markers of disease activity (disease activity scores, albumin, CRP) also associated with low IFX. Circulating TNFα was higher throughout induction in non-responders with ulcerative colitis but not Crohn's disease.

CONCLUSION

IBD patients with primary IFX failure generally have lower IFX trough than responders during early induction phase. Pharmacokinetic failure seems common in ulcerative colits, whereas pharmacodynamic failure appears common in Crohn's disease.

Optimizing Antitumor Necrosis Factor Treatment in Pediatric Inflammatory Bowel Disease With Therapeutic Drug Monitoring

Biological agents have revolutionized inflammatory bowel disease treatment but primary nonresponse and secondary loss of response are common with resulting adverse outcomes. Clinical trials demonstrated an association between serum drug concentrations, as well as the presence of antidrug antibodies, and loss-of-response. Therapeutic drug monitoring (TDM), defined as the evaluation of drug concentrations and antidrug antibodies, is appearing as a strategy to optimize treatment and take full advantage from these drugs. TDM appears to be a promising tool in clinical practice, especially in pediatric patients, who have pronounced fluctuations in the pharmacokinetics of the drugs.The authors present a literature review about antitumor necrosis factor therapy optimization based on personalized treatment strategies according to TDM and possible strategies to recapture loss of response, including an algorithm for practical management.

Therapeutic drug monitoring in patients on biologics: lessons from gastroenterology

PURPOSE OF REVIEW

To give an overview on the role of therapeutic drug monitoring (TDM) of biologics in patients with inflammatory bowel disease (IBD).

RECENT FINDINGS

Numerous prospective exposure-response relationship studies and post-hoc analyses of randomized controlled trials (RCTs) show a positive correlation between biologic drug concentrations and favorable clinical outcomes in IBD. These studies also demonstrate that higher drug concentrations appear to be needed to achieve more stringent objective therapeutic outcomes. Reactive TDM rationalizes the management of primary nonresponse and secondary loss of response to antitumor necrosis factor (anti-TNF) therapy and is more cost-effective when compared with empiric dose optimization. Furthermore, recent data suggest that proactive TDM, with the goal of targeting a threshold drug concentration, is associated with better therapeutic outcomes when compared with empiric dose escalation and/or reactive TDM of infliximab or adalimumab. Finally, proactive TDM can also efficiently guide infliximab de-escalation or discontinuation in patients with IBD in remission.

SUMMARY

Reactive TDM is currently considered as standard of care, whereas proactive TDM is emerging as a new therapeutic strategy for better optimizing anti-TNF therapy in IBD. However, more data from prospective studies are needed before a wide implementation of TDM-based algorithms in real life clinical practice for newer biologics.

Therapeutic Drug Monitoring of Biologics During Induction to Prevent Primary Non-Response

Biologic therapies have revolutionized the management of inflammatory bowel disease [IBD], but primary and secondary non-responses occur in a significant proportion of patients. Therapeutic drug monitoring [TDM] now has an established role in the treatment algorithm for managing secondary loss of response to anti-tumour necrosis factor [anti-TNF] agents during maintenance therapy. Data to support the use of TDM in the management of secondary loss of response to vedolizumab and ustekinumab are emerging. The potential to prevent primary non-response to biologic agents during induction is of equal, and potentially greater, clinical importance. Again, most data supporting the use of 'proactive' TDM during induction pertains to the use of anti-TNF agents, but signals of efficacy for the use of TDM during induction with other biologic classes are now appearing. This review aims to summarize data on the use of TDM during induction to prevent pharmacokinetic primary non-response to all three classes of biologic therapy currently available for the treatment of IBD.

How, When, and for Whom Should We Perform Therapeutic Drug Monitoring?

The implementation of therapeutic drug monitoring (TDM) in the inflammatory bowel disease practice has evolved over the years. In the early days, the focus was merely on measuring and reporting drug concentrations. Later, these concentrations were considered in light of target concentrations that are related to clinical response. This not only allowed passively predicting a patient's future response, but it also triggered physicians and pharmacists to actively use the information to optimize the drug dosage to induce and maintain a clinical response in the future. Although reactive TDM, testing at time of loss of response, is widely accepted in practice, especially for anti-tumor necrosis factor antibodies, there are less data for the other monoclonal antibodies belonging to other classes. Besides reactive testing, there is a movement toward proactively adjusting biologic dosing to prevent loss of response, in keeping with the tight control philosophy of inflammatory bowel disease care. This review highlights the various assays available to measure drug concentrations and antidrug antibodies, as well as algorithmic approaches to TDM, the unmet needs and required studies to enable pharmacokinetics principles to be applied in the future.

Usefulness of therapeutic drug monitoring of infliximab during the induction period in patients with inflammatory bowel disease

INTRODUCTION

previous studies have shown that higher infliximab trough levels are associated with favorable short-term and long-term therapeutic outcomes in inflammatory bowel disease. There is a need to determine which patients could benefit from proactive therapeutic drug monitoring in the induction phase. The aim of this study was to evaluate the pharmacokinetic variability of infliximab, determine the factors associated with achieving target infliximab trough levels in the induction phase and analyze the clinical and biochemical response at week 26 of treatment.

PATIENTS AND METHODS

a retrospective observational study was performed of patients with inflammatory bowel disease and data available on serum levels of infliximab during the induction period. The percentage of patients that achieved target infliximab trough levels at week 6 was determined. Clinical remission and response and biochemical remission were evaluated at week 26.

RESULTS

thirty patients were included and only 13 (43.3 %) had infliximab trough levels > 15 µg/mL at week 6. A clinical response was observed during the maintenance period in 71.4 % of patients, their infliximab levels were significantly higher than in non-responders (6.3 µg/mL [IQR: 6.7] vs 1.0 µg/mL [IQR: 5.0], respectively; p = 0.016). Likewise, 53.6 % of patients achieved biochemical remission (responders 6.2 µg/mL [IQR: 5.2] vs non-responders 3.2 µg/mL [IQR: 5.0]; p = 0.031).

CONCLUSION

less than half of patients had target infliximab levels during the induction period. Therapeutic drug monitoring during this period is related to the achievement of therapeutic levels of infliximab and may lead to a better clinical response in these patients.

Prediction of response to biological treatment with monoclonal antibodies in severe asthma

In recent years, major developments have occurred in severe asthma management. Different asthma phenotypes and subgroups have been identified and new treatment options have become available. A total of five monoclonal antibodies are currently approved in severe asthma treatment: omalizumab, mepolizumab, reslizumab, benralizumab and dupilumab. These drugs have been shown to reduce exacerbations and to have an oral corticosteroid-sparing effect in many severe asthma patients. However, biological treatment is not successful in all patients and should be discontinued in non-responsive patients. Treating the right patient with the right biologic, and therefore biologic response prediction, has become a major point of interest in severe asthma management. A variety of response outcomes is utilized in the different clinical trials, as well as a huge range of potential predicting factors. Also, regarding the timing of the response evaluation, there are considerable differences between studies. This review summarizes the results from studies on predicting responses and responders to biological treatment in severe asthma, taking into account clinical, functional and inflammatory parameters assessed prior to the start of treatment as well as following a few months of therapy. In addition, future perspectives are discussed, highlighting the need for more research to improve patient identification and treatment responses in the field of biological treatment in severe asthma.

Trough Levels of Infliximab at Week 6 Are Predictive of Remission at Week 14 in Pediatric Crohn's Disease

OBJECTIVE

Infliximab (IFX) is a frequent therapeutic option for Crohn disease (CD) patients. Early detection of responders to IFX is critical for the management of CD in order to avoid long-term exposure to the drug without benefit. This retrospective study aimed at analysing which early parameters recorded during the induction period are able to predict response to IFX during the maintenance period in pediatric CD.

PATIENTS AND METHODS

Medical records of all CD patients ages from 2 to 18 years who received IFX at a tertiary IBD center were retrospectively analyzed. Children were classified in 3 groups according to their response at week 14 (W14) remission, clinical response or , no response. The factors recorded at W0, W2, and W6, which were associated with remission at W14 were analyzed using a logistic regression.

RESULTS

Among the 111 patients included, 74.8% patients were responders to IFX at W14, including 38.7% in clinical remission and 36% with partial clinical response. Clinical remission at W14 was associated with normal growth (P < 0.01), and normal albuminemia (P = 0.01) at baseline, It was also associated with trough levels to IFX >8.3 μg/ml at week 6 (P < 0.01).

CONCLUSION

Trough levels to IFX >8.3 μg/ml at week 6 are predictive of remission at W14 for luminal disease.

Efficacy of Anti-TNF Therapy for the Treatment of Patients with Moderate-to-Severe Inflammatory Bowel Disease; a First Iranian Report

BACKGROUND The anti-TNF drugs are shown to be highly effective in treatment of patients with moderate-tosevere inflammatory bowel disease (IBD). Here, we aimed to assess the efficacy and safety of antiTNF therapy at the national level. METHODS IBD patients aged 15 > years who received Infliximab and/or CinnoRA® between 2013 to July 2018 were identified. The data extracted from medical dossier and telephonic interview. The efficacy of therapy was defined as time to drug discontinuation or need for IBD-related surgery. The safety was assessed based on patient's reported adverse events. RESULTS We included 315 patients. The mean age of patients was 37.2 years and 62.2% of them developed the disease before age 30 years. Involvement of masculoskeletal system was reported in 7.3% of patients. Partial and complete response to Anti-TNF therapy was seen in 67% of patients. About 16% of patients did not respond to induction therapy and 16.9% of patients lost their response to Anti-TNF during one year. No serious adverse events, serious opportunistic infection, tuberculosis and malignancies reported by patients. Two patients reported pneumonia. CONCLUSION This study for the first time in our country, provides the evidences for efficacy of anti-TNF therapy in moderate to severe IBD patients.

Therapeutic Drug Monitoring and Outcome of Infliximab Therapy in Pediatric Onset Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) with pediatric onset has become more prevalent during past decades. Thus, the number of patients with moderate to severe disease subtype treated with antagonists to tumor necrosis factor alpha (TNFα) has concurrently risen. Most pediatric patients initially respond to these drugs but will need dose escalation during the first year of therapy. As pediatric data regarding therapeutic drug monitoring during therapy with TNFα-blocker adalimumab are sparse, this review focuses on the literature on therapeutic drug monitoring of infliximab and how it may guide management.

Azathioprine Is Useful for Maintaining Long-term Remission Induced by Tacrolimus for the Treatment of Ulcerative Colitis: An Inverse Probability of a Treatment Weighing Analysis

Objective The need for and efficacy of immunomodulators for maintaining remission after tacrolimus therapy have not been sufficiently defined. This study evaluated the efficacy of immunomodulators for maintaining remission in patients with ulcerative colitis after tacrolimus therapy. Methods Patients with active ulcerative colitis who started oral tacrolimus between January 2009 and September 2017 and were responsive were retrospectively evaluated. Long-term outcomes were compared using Cox proportional hazard regression with inverse probability of treatment weighting. Results Among the 63 patients in the study, 45 received immunomodulators. During the follow-up, 30 patients (47.6%) experienced a relapse. The relapse-free survival rate was significantly worse in the group that did not receive immunomodulators than in those that did (p=0.01, log-rank test); the 2-year relapse-free rates were 22.5% and 63.6% in the non-immunomodulator and immunomodulator groups, respectively. A multivariate analysis showed immunomodulator treatment to be an independent protective factor for clinical relapse (adjusted hazard ratio: 0.35, 95% confidence interval: 0.16-0.78, p=0.01). A Cox regression analysis using inverse probability of treatment weighting also showed that immunomodulator maintenance therapy was correlated with a longer relapse-free survival (hazard ratio: 0.31, 95% confidence interval: 0.15-0.64, p<0.01), A similar response was also observed in non-steroid-dependent patients (hazard ratio: 0.36, 95% confidence interval: 0.14-0.99, p=0.047). No serious adverse events occurred due to tacrolimus or immunomodulator, and immunomodulator use did not increase the incidence of adverse events caused by tacrolimus. Conclusion Our data suggest that the use of immunomodulators to maintain remission after tacrolimus therapy is beneficial for patients with ulcerative colitis.

Therapeutic drug monitoring of infliximab in spondyloarthritis. A review of the literature

Available evidence indicates that a therapeutic drug monitoring strategy leads to major cost savings related to the anti-tumour necrosis factor-α therapy in both inflammatory bowel disease and rheumatoid arthritis (RA) patients, with no negative impact on efficacy. However, although the systematic use of therapeutic drug monitoring could potentially be beneficial and economically acceptable to drug dose optimization, it is not justifiable for all drugs. Infliximab (IFX) is a chimeric monoclonal immunoglobulin G1 targeting tumour necrosis factor. It has been approved for the treatment of immuno-inflammatory diseases, including RA, ankylosing spondylitis, psoriatic arthritis, Crohn's disease and ulcerative colitis. IFX's pharmacokinetics is highly variable and influences clinical response in chronic inflammatory diseases. Clinical response increases with IFX trough concentrations in RA, ankylosing spondylitis, inflammatory bowel disease and psoriatic patients. Target concentrations predictive of good clinical response were proposed in RA, Crohn's disease and ulcerative colitis. The purpose of this article is to review the current literature surrounding IFX serum concentrations and their related parameters with disease activity in patients with spondyloarthritis. Gathering information about the efficacy of IFX in patients with spondyloarthritis and relating IFX serum concentrations to disease activity were the main goals of this study.