Association of trough serum infliximab to clinical outcome after scheduled maintenance treatment for Crohn's disease

A Novel Radiomics Nomogram for the Prediction of Secondary Loss of Response to Infliximab in Crohn's Disease

Purpose

The prediction of the loss of response (LOR) to infliximab (IFX) is crucial for optimizing treatment strategies and shifting biologics. However, a secondary LOR is difficult to predict by endoscopy due to the intestinal stricture, perforation, and fistulas. This study aimed to develop and validate a radiomic nomogram for the prediction of secondary LOR to IFX in patients with Crohn’s disease (CD).

Patients and Methods

A total of 186 biologic-naive patients diagnosed with CD between September 2016 and June 2019 were enrolled. Secondary LOR was determined during week 54. Computed tomography enterography (CTE) texture analysis (TA) features were extracted from lesions and analyzed using LIFEx software. Feature selection was performed by least absolute shrinkage and selection operator (LASSO) and ten-fold cross validation. A nomogram was constructed using multivariable logistic regression, and the internal validation was approached by ten-fold cross validation.

Results

Predictors contained in the radiomics nomogram included three first-order and five second-order signatures. The prediction model presented significant discrimination (AUC, 0.880; 95% CI, 0.816–0.944) and high calibration (mean absolute error of = 0.028). Decision curve analysis (DCA) indicated that the nomogram provided clinical net benefit. Ten-fold cross validation assessed the stability of the nomogram with an AUC of 0.817 and an accuracy of 0.819.

Conclusion

This novel radiomics nomogram provides a predictive tool to assess secondary LOR to IFX in patients with Crohn’s disease. This tool will help physicians decide when to switch therapy.

Immunogenicity of biologics used in the treatment of inflammatory bowel disease: A review

PURPOSE OF THE REVIEW

Here we critically evaluate the literature on immunotherapy failure in inflammatory bowel disease patients. In particular anti-drug antibody production, and subsequently loss of response as the primary cause of immunotherapy failure in IBD patients. The benefits of shifting from the "standard" empirical dose escalation approach to therapeutic drug monitoring with anti-TNFα therapy is explored.

RECENT FINDINGS

The American Gastroenterology Association and British Society of Gastroenterology both currently recommend the use of reactive therapeutic drug monitoring to guide treatment, following loss of response in inflammatory bowel disease patients with active disease. However, further research is required to prove the efficacy of a proactive therapeutic drug monitoring approach alone in remitted IBD patients.

SUMMARY

A combination of personalised monitoring approach for anti-drug antibodies and therapeutic drug monitoring could provide beneficial treatment outcome for people with inflammatory bowel disease by predicting drug failure prior to clinical symptoms and allowing timely switching to an alternative drug.

Anti-Drug Antibodies in Patients with Inflammatory Bowel Diseases Treated with Biosimilar Infliximab: A Prospective Cohort Study

Reports of the prevalence of antibodies to infliximab (anti-drug antibodies, ADA) are inconsistent due in part to the various assay formats used to monitor immunogenicity in the clinic and under clinical trial settings. This study aimed to determine the frequency of ADA in patients with inflammatory bowel disease (IBD) during induction and maintenance therapy with biosimilar infliximab (CT-P13) using the ELISA (enzyme-linked immunosorbent assay) method. In this prospective single-center study, we analyzed the incidence of ADA and the relationship between the presence of ADA and the following variables: gender, type of disease, immunosuppressive therapy used, and duration of treatment. A total of 84 patients with IBD received CT-P13 and were followed up for an average of 7 months. We found ADA in 50% of the patients with undetectable levels of the drug. The percentage of persons with antibodies detected during induction treatment was 11.3% compared to 9.6% during maintenance therapy. The analysis showed no relationship between response to treatment and antibody titers (p = 0.381). The study showed a statistically significant relationship between undetectable levels of CT-P13 and the presence of ADA at week 6 of therapy (i.e., ADA were detected in all the patients with undetectable levels of CT-P13). Patients with IBD and undetectable levels of CT-P13 before administration of the third induction dose were at high risk of the presence of anti-drug antibodies as well as primary non-response.

CORRELATION BETWEEN TROUGH LEVELS OF INFLIXIMAB AND POSTOPERATIVE ENDOSCOPIC RECURRENCE IN CROHN'S DISEASE PATIENTS SUBMITTED TO ILEOCOLONIC RESECTIONS: A SYSTEMATIC REVIEW

BACKGROUND

The rates of postoperative endoscopic recurrence (PER) in patients with Crohn's disease (CD) are consistent. Anti-TNF therapy has been increasingly used in the postoperative setting, despite the lack of robust data in the literature on the measurement of trough levels and consequences of their use.

OBJECTIVE

The aim of this review was to assess trough levels of infliximab (IFX) in CD patients after ileocolonic resections in correlation with the presence of PER.

METHODS

We searched for studies that evaluated trough levels of IFX in patients with CD, who underwent ileocaecal resections, and correlated them with the presence of PER. We used MEDLINE through PubMed and CENTRAL Cochrane library databases, and after matching the inclusion criteria, the studies were methodologically evaluated with qualitative analysis of the data.

RESULTS

A total of 155 studies were initially identified in the databases search and only four matched the inclusion criteria. They comprised one prospective cohort study, one randomized controlled trial and two retrospective cohort studies, the last one performed in pediatric patients. This evidence suggested the correlation of PER with low trough levels of IFX and the presence of antibodies to the drug. The quality of the evidence generated varied from very low to high, due to the heterogeneity found between the studies and the risks of bias that were identified.

CONCLUSION

Low levels of IFX and the presence of antibodies to the drug were directly associated with increased PER rates in patients with CD, who underwent ileocolonic resections. Controlled and randomized clinical trials with adequate methodological quality are warranted to confirm the conclusions from this systematic review.

Predictors of Infliximab Trough Concentrations in Inflammatory Bowel Disease Patients Using a Repeated-Measures Design

BACKGROUND AND AIMS

Treating patients based on a treat-to-trough approach has been shown to be a cost-effective strategy for inflammatory bowel disease (IBD) patients who have become unresponsive to infliximab (IFX). However, the documented evidence for this is limited, and some controversy remains regarding the use of routine proactive therapeutic drug monitoring (TDM). To support routine TDM of IFX and regimen optimization in IBD patients, more in-depth knowledge of the covariates that affect the pharmacokinetic (PK) variability of IFX is needed. The aim of this study was to identify the characteristics of the patient, disease, and treatments that influence IFX PK and exposure in our cohort of IBD patients using a repeated-measures design.

METHODS

We performed a prospective observational study of adult IBD patients who received IFX between July 2013 and March 2017. We obtained repeated IFX trough concentration (Cmin) measurements and implemented a previously described population pharmacokinetic model to estimate individual clearance (CL). From the individual primary parameters, the area under the curve (AUC), half-life (t1/2), and central elimination rate constant (K10) were estimated. We performed a repeated-measures analysis to evaluate whether patient characteristics, disease status, concomitant immunosuppressive therapy, and immunogenicity are associated with IFX Cmin and PK parameters.

RESULTS

We collected 429 Cmin measurements from 112 patients. The median of the Cmin values was 3.62 mg/L (1.47-6.02). Antibodies to IFX (ATI) were detected in 14 patients. The predicted median AUC was 28,421 mg/h/L (22,336-36,903). The median individual predicted CL, K10, and t1/2 values were 4.77 mL/kg/day (3.88-5.90), 0.09 days (0.08-0.12), and 12.22 days (9.49-14.87), respectively. IFX Cmin, AUC, CL, and K10 were significantly influenced by ATI and serum albumin concentrations. Moreover, body weight was significantly associated with AUC, CL, and K10. Patients receiving concurrent immunosuppressive therapy had higher Cmin and AUC values and lower CL and K10 values than those treated with IFX monotherapy. We also observed high intrapatient variability in Cmin values during the study period.

CONCLUSIONS

In this repeated-measures study in a population of IBD patients, we observed significant associations between ATI, serum albumin concentration, concomitant immunosuppressive therapy, body weight and gender, and IFX Cmin, and CL. The high PK variability observed in this study supports the need for proactive TDM to optimize the use of IFX as early as possible in IBD patients.

Is There a Role for Therapeutic Drug Monitoring in Patients with Hidradenitis Suppurativa on Tumor Necrosis Factor-α Inhibitors?

Tumor necrosis factor-α inhibitors, adalimumab and infliximab, are at the forefront of biologic therapy for the management of moderate-to-severe hidradenitis suppurativa, with adalimumab as currently the only approved medication for this condition. In treating patients, primary or secondary lack of response (also termed suboptimal response) is a major burden for both patients and healthcare systems and is a challenge with biologics in part owing to the development of anti-drug antibodies following treatment. To overcome this, therapeutic drug monitoring may be conducted proactively or reactively to a patient's suboptimal response guided by measurements of trough serum drug concentrations and levels of anti-drug antibodies. While strong evidence to support the utility of therapeutic drug monitoring exists in patients with inflammatory bowel disease, current information is limited in the context of hidradenitis suppurativa. We sought to summarize the available evidence and to present the role of therapeutic drug monitoring and other dose optimization strategies in improving clinical response in patients with hidradenitis suppurativa treated with tumor necrosis factor-α inhibitors.

Therapeutic Drug Monitoring for Current and Investigational Inflammatory Bowel Disease Treatments

This article reviews therapeutic drug monitoring (TDM) use for current inflammatory bowel disease (IBD) treatments. IBD comprises Crohn's disease and ulcerative colitis-chronic gastrointestinal inflammatory disorders. Treatment options for moderate to severe IBD include thiopurines; methotrexate; biologic agents targeting tumor necrosis factor, α4β7 integrin or interleukins 12 and 23; and Janus kinase inhibitors. TDM is recommended to guide treatment decisions for some of these agents. Published literature concerning TDM for IBD treatments was reviewed. S.D.L., R.S., and E.V.L. drew on their clinical experiences. Polymorphisms resulting in altered enzymatic activity inactivating thiopurine metabolites can lead to myelotoxicity and hepatotoxicity. Increased elimination of biologic agents can result from immunogenicity or higher disease activity, leading to low drug concentration and consequent nonresponse or loss of response. TDM may aid treatment and dose decisions for individual patients, based on monitoring metabolite levels for thiopurines, or serum drug trough concentration and antidrug antibody levels for biologic agents. Challenges remain around TDM implementation in IBD, including the lack of uniform assay methods and guidance for interpreting results. The Janus kinase inhibitor tofacitinib is not impacted by enzyme polymorphisms or disease activity, and is not expected to stimulate the formation of neutralizing antidrug antibodies. TDM is associated with implementation challenges, despite the recommendation of its use for guiding many IBD treatments. Newer small molecules with less susceptibility to patient variability factors may fulfill the unmet need of treatment options that do not require TDM, although further study is required to confirm this.

Infliximab therapy intensification based on endoscopic activity is related to suppress treatment discontinuation in patients with Crohn disease: A retrospective cohort study

ABSTRACT

Administering double doses of infliximab or shortening its dosing interval for patients with Crohn disease who experience a loss of response to treatment is an accepted treatment method; however, the effectiveness and appropriate timing of treatment intensification remain unclear. We examined the treatment outcomes of patients with Crohn disease receiving infliximab therapy intensification.Among 430 patients with Crohn disease who were seen at our related facilities from July 2002 to July 2018, 46 patients (30 men and 16 women) who were followed up for diminished infliximab effects for >1 year after therapy intensification were included in this study. The relationship between patient background and continuation of therapy intensification was retrospectively examined through a logistic regression analysis.Among the 46 patients, 67.4% (31 cases) continued therapy intensification for 12 months. The treatment discontinuation rate after 12 months (7.1% vs 43.8%, P = .015) and the C-reactive protein levels at the start of therapy intensification (P = .0050) were significantly lower in the group in which treatment was strengthened due to remaining endoscopic findings (n = 14) than that due to clinical symptoms (n = 32). There was no significant difference in the rates of treatment discontinuation after 12 months of treatment strengthening between patients receiving double doses (n = 34) and those with shortened dosing intervals (n = 12).Infliximab treatment discontinuation seems to be less likely to occur in patients with Crohn disease who are receiving infliximab treatment intensification based on endoscopic findings of exacerbations than in patients whose treatment is based on clinical symptoms.

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.

Systematic review and meta-analysis of drug induced liver injury secondary to biologic medications in inflammatory bowel disease

Introduction: Drug-induced Hepatotoxicity and biologic drugs have historically been challenging in IBD. We aim to study the prevalence of hepatotoxicity in adult patients using biologic medications. Methodology: With the guidelines described by PRISMA-P, a detailed search strategy for each electronic database was developed based on PubMed, Medline, and Embase. We include RCTs that assessed the efficacy and hepatotoxicity of biologics in IBD patients. Hepatotoxicity was defined as AST and/or ALT >2x upper limit of normal or cholestasis. The Odds ratio (OR) was calculated with a 95% confidence interval (CI). Heterogeneity was assessed using the Chi2 test and the I2 statistic. Results: 862 records identified in total. After removing the duplicates 564 records were left for review. Four studies did not report on how participants were randomized to treatment groups or how allocation concealment was achieved, we rated these studies at unclear risk of bias for these domains. There was no presence of any heterogeneity among studies by (Chi2= 2.21, df = 6, p = 0.90, and I2 = 0%). Our meta-analysis was conducted on the fixed effects model, with the (0.770, 95% CI [-0.630, 0.957], and p = 0.02). Hepatotoxicity was not related to any TNF-α antagonist. Thiopurine induced liver injury occurred more frequently within the first months of treatment, 50% of cases within the first 3 months (11.4% vs. 2.3%, p < 0.05). Conclusion: When hepatotoxicity occurred, the treatment was withdrawn in thirty one percent of patients. This group of patients had a dose-dependent hepatotoxicity rather than an immunologic hepatitis.

Second Mexican consensus on biologic therapy and small-molecule inhibitors in inflammatory bowel disease

INTRODUCTION

Inflammatory bowel disease (IBD) is a chronic and incurable entity. Therapy with anti-TNF-α agents was the first biologic therapy approved in Mexico for IBD. New biologic agents, such as vedolizumab and ustekinumab, have recently been added, as have small-molecule inhibitors.

AIM

To update the biologic therapeutic approach to IBD in Mexico with new anti-TNF-α agents and novel biologics whose mechanisms of action induce and maintain remission of Crohn's disease and ulcerative colitis (UC).

MATERIALS AND METHODS

Mexican specialists in the areas of gastroenterology and inflammatory bowel disease were summoned to participate. The consensus was divided into 3 modules, with 49 statements. The Delphi method was applied, sending the statements to all participants to be analyzed and edited, before the face-to-face meeting. During said meeting, the clinical studies were shown, emphasizing the level of clinical evidence, and the final discussion and voting round on the level of agreement of all the statements was conducted.

RESULTS

In this second Mexican consensus, recommendations are made for new anti-TNF-α agents, such as golimumab, new biologics with other mechanisms of action, such as vedolizumab and ustekinumab, as well as for the small-molecule inhibitor, tofacitinib.

CONCLUSIONS

The updated recommendations focus on patient-reported outcomes, biologic therapy, small-molecule inhibitors, and the safety aspects of each of the drugs.

Does Perianal Disease Influence the Efficacy of Combination Therapy in Crohn's Disease?

BACKGROUND

Perianal disease is associated with a disabling course of Crohn's disease (CD). We aim to study the impact of perianal disease on CD remission rates, after a 1-year course of infliximab in combination therapy with azathioprine.

METHODS

This was a retrospective, single-center cohort study, including consecutive CD patients on combination therapy, followed for 1 year since induction. The outcome variable was split into clinical and endoscopic remissions. The correlation toward the outcome variable was assessed with univariate and multivariate analysis and a survival assessment, using SPSS software.

RESULTS

We assessed 74 CD patients, of whom 41 (55.4%) were female, with a mean age of 36 years. Thirty-nine percent of the patients presented perianal disease at diagnosis (n = 29). We documented 70.3% clinical and 47.2% endoscopic remissions. Several variables had statistical significance toward the outcomes (endoscopic and clinical remissions) in the univariate analysis. After adjusting for confoundment, patients with perianal disease presented an odds ratio (OR) of 0.201 for achieving endoscopic remission (CI: 0.054-0.75, p value 0.017) and an OR of 0.203 for achieving clinical remission (CI: 0.048-0.862, p value 0.031). Sixty-six patients (89.2%) presented an initial response to treatment, from whom, 20 (30.3%) exhibited at least 1 disease relapse (clinical and/or endoscopic). Patients with perianal disease presented higher probability of disease relapse, displaying statistically significant difference on Kaplan-Meier curves (Breslow p value 0.043).

CONCLUSION

In the first year of combination therapy, perianal disease is associated with an 80% decrease in endoscopic and clinical remission rates and higher ratio of disease relapse.

Optimization of azathioprine dose in combined treatment with anti-TNF-alpha in inflammatory bowel disease

INTRODUCTION

The dose of thiopurine drugs in combined treatments with anti-TNF in inflammatory bowel disease (IBD) has not been clearly established. The purpose of this study is to assess whether the dose of azathioprine influences clinical and biochemical response/remission rates, and anti-TNF drug levels/antibody formation.

MATERIAL AND METHODS

Patients with IBD on combined maintenance treatment with azathioprine and infliximab or adalimumab were selected. Based on the dose of azathioprine, two groups were defined (standard: 2-2.5mg/kg/day; and decreased: less than 2mg/kg/day).

RESULTS

In the IFX group, there were no statistically significant differences (p=0.204) in the rates of remission (39% vs 41.3%), response (10% vs 21.7%) or failure (51.5% vs 37%) depending on the dose of thiopurine drugs. No differences were found between AZA-dose dependent IFX levels (2.46 vs 3.21μg/mL; p=0.211). In the adalimumab group, there were no statistically significant differences (p=0.83) in the rates of remission (66% vs 56%), response without remission (15.38% vs 25%) or failure (18% vs 18%) depending on the dose of thiopurines. With respect to ADA-levels, no differences were found in both groups (7.69 vs 8.23μg/mL; p=0.37).

CONCLUSION

In our experience, no statistically significant differences were found in either anti-TNF levels or clinical-biological response/remission rates based on doses of azathioprine.

Correlation of serum levels of anti-tumor necrosis factor agents with perianal fistula healing in Crohn's disease: a narrative review

With the overspread use of measurement of serum levels of anti-tumor necrosis factor (TNF) agents (therapeutic drug monitoring, TDM), new therapeutic strategies have been used in the management of Crohn’s disease (CD). Different targets are correlated with increased levels of circulating drugs. Recent evidence demonstrated that higher serum levels of anti-TNF agents may be associated to better outcomes in perianal fistulizing CD (PFCD). Overall, patients with healed fistulas had higher serum levels of infliximab and adalimumab as compared to those with active drainage. This was demonstrated in some cohort studies, in induction and maintenance, in adults and children with PFCD. In this narrative review, authors summarize current evidence on the use of serum level measurement of anti-TNF agents and its correlation with perianal fistula healing in CD patients. Data on the use of TDM in PFCD is discussed in detail. The retrospective design of the studies and the lack of objective parameters to measure fistula healing are the main limitations of published data. Prospective studies, with central reading of objective radiological parameters, such as pelvic magnetic resonance imaging scores, can improve the level of evidence on the possible advantages of TDM in perianal fistula in CD and are warranted.

Enhancing treatment success in inflammatory bowel disease: Optimising the use of anti-TNF agents and utilising their biosimilars in clinical practice

Anti-tumour necrosis factor (TNF) agents such as infliximab and adalimumab have greatly altered the treatment landscape in inflammatory bowel disease (IBD). However, there are remaining unmet needs and opportunities to optimise their use. Recent data suggest that proactive therapeutic drug monitoring may lead to more efficient usage of these agents, with potential for higher rates of corticosteroid-free clinical remission than with reactive monitoring. Expanded application of faecal calprotectin measurements may also be valuable, given the ease of use of the assay and its proven effectiveness as a diagnostic tool and predictor of relapse risk. From a practical viewpoint, improved multidisciplinary working may be essential to optimise patient care, with IBD nurse specialists playing an increasingly central role within this model. Finally, the availability of biosimilars of the anti-TNF agents allow drug costs to be reduced without compromising safety or efficacy - thereby providing opportunities to improve accessibility. Alongside extensive data on originator to biosimilar infliximab switch, new studies are beginning to demonstrate the safety of biosimilar to biosimilar switch, as well as adalimumab biosimilar transitions. The risk of a nocebo effect when switching to a biosimilar can be reduced through improved patient education and preparation.

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.

Evaluation of two point of care technologies for measuring monoclonal antibody therapeutic-A concentrations in blood

Aim: Current blood monitoring methods require sample collection and testing at a central lab, which can take days. Point of care (POC) devices with quick turnaround time can provide an alternative with faster results, allowing for real-time data leading to better treatment decisions for patients. Results/Methodology: An assay to measure monoclonal antibody therapeutic-A was developed on two POC devices. Data generated using 75 serum samples (65 clinical & ten spiked samples) show correlative results to the data generated using Gyrolab technology. Conclusion: This case study uses a monoclonal antibody therapeutic-A concentration assay as an example to demonstrate the potential of POC technologies as a viable alternative to central lab testing with quick results allowing for real-time decision-making.

Is Therapeutic Drug Monitoring for Anti-tumour Necrosis Factor Agents in Adults With Inflammatory Bowel Disease Ready for Standard of Care? A Systematic Review and Meta-analysis

INTRODUCTION

Using therapeutic drug monitoring [TDM] in adult patients with inflammatory bowel disease [IBD] remains controversial. We conducted a systematic review and meta-analysis to answer four clinical PICO [Population, Intervention, Comparator, Outcome] questions.

METHODS

We searched MEDLINE, Embase, Web of Science, and Cochrane Central from inception to June 30, 2019. Remission was defined by the manuscripts' definitions of clinical remission. Data were analysed using RevMan 5.3. Quality of evidence was assessed with GRADE methodology.

RESULTS

We identified and screened 3365 abstracts and 11 articles. PICO 1 Reactive vs No TDM: six studies pooled showed 57.1% [257/450] failed to achieve remission following reactive TDM vs 44.7% [268/600] in the no TDM group (risk ratio [RR]: 1.14; 95% confidence interval [CI] 0.88-1.47). PICO 2 Proactive vs no TDM: five studies pooled showed 19.5% [75/384] failed to maintain remission in the proactive TDM group vs 33.4% [248/742] in the no TDM group [RR: 0.60; 95% CI 0.35-1.04]. PICO 3 Proactive vs Reactive TDM: two retrospective studies pooled showed 14.2% [26/183] failure to maintain remission in the proactive TDM group and 64.7% [119/184] in the reactive TDM group [RR: 0.22; 95% CI 0.15-0.32]. PICO 4 TDM [proactive/reactive] vs No TDM: we pooled 10 studies showing 39.7% [332/837] failed to achieve remission in the TDM [proactive/reactive] cohort vs 40.3% [428/1063] in the no TDM cohort [RR: 0.94; 95% CI 0.77-1.14]. Overall, the quality of evidence in each PICO was very low when using GRADE.

CONCLUSIONS

This meta-analysis shows that data supporting use of TDM in adults are limited and of very low quality. Further well-designed randomized controlled trials are needed to determine the place of TDM in clinical practice.

Infliximab trough levels: A comparison between the Quantum Blue Infliximab assay and the established ELISA

BACKGROUND AND AIM

Therapeutic drug monitoring of infliximab (IFX) using the established laboratory-based enzyme-linked immunosorbent assay (ELISA) cannot produce results fast enough to allow IFX dose adjustments prior to each IFX infusion. We investigate the validity of IFX trough levels obtained through the Quantum Blue IFX (QB-IFX) rapid assay compared with the established ELISA.

METHODS

Adult inflammatory bowel disease patients receiving maintenance IFX infusions at Middlemore Hospital and Dunedin Public Hospital were prospectively recruited from July to October 2016. Serum samples were stored at -40 °C until processed using QB-IFX by a clinician at Middlemore Hospital and a research staff at Dunedin Public Hospital strictly following the manufacturers' instructions in an open label fashion.

RESULTS

Forty four inflammatory bowel disease patients were recruited. Median duration of IFX therapy was 21 months (interquartile range: 12-44). Overall, the correlation between ELISA and QB-IFX trough levels was 0.73 (95% confidence interval [CI]: 0.53-0.85). The sensitivity and specificity of a QB-IFX level < 7 in detecting an ELISA level < 7 were 0.79 (95% CI: 0.59-0.92) and 0.75 (95% CI: 0.48-0.93), respectively. Conversely, the sensitivity and specificity of a QB-IFX level < 2 detecting an ELISA level < 2 were 1.00 (95% CI: 0.52, 1.00) and 0.97 (95% CI: 0.85, 1.00), respectively.

CONCLUSION

The QB-IFX had excellent sensitivity and specificity for IFX levels < 2 obtained with the established ELISA. Therefore, QB-IFX could be used for real time dosing decisions when the IFX level is low and dose escalation is required.

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

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

A portable optical-fibre-based surface plasmon resonance biosensor for the detection of therapeutic antibodies in human serum

Different lines of evidence indicate that monitoring the blood levels of therapeutic antibodies, characterized by high inter-individual variability, can help to optimize clinical decision making, improving patient outcomes and reducing costs with these expensive treatments. A surface plasmon resonance (SPR)-based immunoassay has recently been shown to allow highly reliable and robust monitoring of serum concentrations of infliximab, with significant advantages over classical ELISA. The next level of advancement would be the availability of compact and transportable SPR devices suitable for easy, fast and cheap point-of-care analysis. Here we report the data obtained with recently developed, cost-effective, optical-fibre-based SPR sensors (SPR-POF), which allow the construction of a compact miniaturized system for remote sensing. We carried out an extensive characterization of infliximab binding to an anti-infliximab antibody immobilized on the SPR-POF sensor surface. The present proof-of-principle studies demonstrate the feasibility of the proposed SPR-POF platform for the specific detection of infliximab, in both buffer and human serum, and pave the way for further technological improvements.

Serum oncostatin M at baseline predicts mucosal healing in Crohn's disease patients treated with infliximab

BACKGROUND

Oncostatin M is upregulated in Crohn's disease inflamed intestinal mucosa, and has been suggested as a promising biomarker to predict responsiveness to anti-TNF therapy in patients with inflammatory bowel diseases.

AIM

To evaluate the suitability of serum oncostatin M as a predictive marker of response to infliximab in Crohn's disease.

METHODS

We included patients treated with infliximab monotherapy. All patients underwent colonoscopy at week 54 to evaluate mucosal healing. Serum oncostatin M and faecal calprotectin were measured at baseline and after 14 weeks of treatment. Mann-Whitney test was used to evaluate correlation of oncostatin M and faecal calprotectin at baseline and week 14 with mucosal healing at week 54. Their accuracy in predicting mucosal healing was assessed by area under the curve (AUC).

RESULTS

In a cohort of 45 included patients, 27 displayed mucosal healing. At both baseline and week 14, oncostatin M levels were significantly lower in patients with mucosal healing than in patients not achieving this endpoint (P < 0.001). Faecal calprotectin levels at week 14 were lower also in responders than nonresponders (P < 0.001). Oncostatin M values at baseline and week 14 were significantly associated (Spearman correlation = 0.92, P < 0.001). The diagnostic accuracy of oncostatin M at baseline in predicting mucosal healing (AUC = 0.91) was greater than faecal calprotectin (AUC = 0.51, P < 0.001).

CONCLUSION

These results suggest that oncostatin M can predict the outcome of infliximab treatment. Compared with faecal calprotectin, the predictive capability of oncostatin M was appreciable at baseline, thus indicating oncostatin M as a promising biomarker for driving therapeutic choices in Crohn's disease.

Prediction of treatment failure during infliximab induction therapy in inflammatory bowel disease patients based on pharmacokinetic and pharmacodynamic modeling

BACKGROUND

In infliximab (IFX) treatment for Crohn's disease (CD) and ulcerative colitis (UC), it is difficult to predict treatment failure during the induction phase. In the present study for optimal IFX treatment, we attempted to estimate serum IFX concentration and clinical response in individual patients during the induction phase to predict the indication of therapeutic effect and the possibility of treatment failure in the maintenance phase.

METHODS

We estimated pharmacokinetic and pharmacodynamic (PK/PD) parameters and predicted the serum IFX concentration and clinical response using a PK/PD model and Markov chain Monte Carlo Bayesian analysis method during the induction phase. Then, we determined whether the indication of therapeutic effect between predicted and observed clinical response were matched during the maintenance phase.

RESULTS

Data obtained from 15 patients were analyzed. The correlation between predicted and observed values of serum IFX concentration (Pearson product-moment correlation coefficient, 0.700; P < 0.0001, n = 68) and clinical response of CD patients (0.790; P < 0.0001, n = 25) and UC patients (0.702; P = 0.0004, n = 21) were significantly high. The indication of therapeutic effect at the final time point of each patient (from day 115 to day 203) were successfully predicted in 14 of 15 patients (93.3%).

CONCLUSIONS

This study presents prediction of serum IFX concentration and clinical response in individual patients during induction therapy, with presumption of the indication of therapeutic effect and the treatment failure in the maintenance phase. Our results show the possibility of optimizing IFX therapy during the induction phase.

Exposure-Response Relationship of Certolizumab Pegol and Achievement of Low Disease Activity and Remission in Patients With Rheumatoid Arthritis

Anti-tumor necrosis factor (anti-TNF) drugs are often prescribed for the treatment of rheumatoid arthritis (RA) and other immune-mediated inflammatory diseases. Although this treatment has been shown to be effective in many patients, up to 40% of patients do not achieve disease control. Drug concentration in plasma may be a factor affecting the observed variability in therapeutic response. In this study, we aimed to identify the plasma concentrations of the anti-TNF certolizumab pegol (CZP), associated with improvement in disease activity in patients with RA. Data were pooled from three randomized, controlled clinical trials with a combined total of 1,935 patients analyzed. Clinical outcomes of low disease activity (LDA) and remission were defined as Disease Activity Score in 28 joints with C-reactive protein (DAS28(CRP)) ≤ 2.7 and < 2.3, respectively. Quartile analysis results indicated that there may be an exposure-response relationship between CZP concentration and LDA/remission outcomes at weeks 12 and 24; the association was strongest for LDA (P < 0.05). Receiver operating characteristic (ROC) analysis showed that CZP concentrations ≥ 28.0 μg/ml at week 12, and ≥ 17.6 μg/ml at week 24, were associated with a greater likelihood of achieving LDA/remission outcomes. Although confirmatory studies are warranted to define the optimal CZP therapeutic range at weeks 12 and 24, these data indicate that CZP concentrations may be associated with improvement of disease activity.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Treatment of Pediatric Inflammatory Bowel Disease with Biologic Therapies

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Modelling of the relationship between infliximab exposure, faecal calprotectin and endoscopic remission in patients with Crohn's disease

AIMS

Evidence for the benefits of pharmacokinetic (PK) and pharmacodynamic (PD) monitoring of infliximab in patients with Crohn's disease (CD) remains scarce. We aimed to develop a population (pop)PK/PD model to characterise the infliximab dose-exposure-biomarker-response (faecal calprotectin [fCal] and endoscopic remission [ER]) relationship.

METHODS

Data were obtained from 116 patients with CD in a phase 4 dose-escalation study. Three sequential models were developed: a 2-compartment popPK model linking infliximab dose to exposure; an indirect response popPK/PD model describing the inhibitory effect of infliximab exposure on fCal; and a first-order Markov popPD model linking fCal to transitions between states of ER, no ER and dropout.

RESULTS

Infliximab clearance increased with increasing fCal, decreasing albumin, increasing CD activity index and presence of anti-drug antibodies. Baseline fCal increased with increasing C-reactive protein and decreasing platelet count. Lower fCal increased the probability of attaining ER and decreased the probability of losing ER. Probability of dropping out given an earlier state of absence of ER increased with time. Large interpatient PK and PD variability resulted in a flat dose-response curve. Predicted fraction of patients achieving ER was 45% [30-61] (median [interquartile range], n = 50 000) when on 5 mg/kg infliximab (~46% observed in data). Simulations with 10 mg/kg induction doses predicted an increase to 48% [32-63]. This minor benefit at the population level argues against systematic 10 mg/kg induction dosing in all patients.

CONCLUSION

Model-informed infliximab dose optimisation towards a predefined fCal concentration (while accounting for PK and PD variability) may improve effectiveness of infliximab therapy.

Pharmacokinetics, Pharmacodynamics, and Immunogenicity of Infliximab in Pediatric Inflammatory Bowel Disease: A Systematic Review and Revised Dosing Considerations

OBJECTIVES

Infliximab (IFX), a monoclonal antibody directed against tumor necrosis factor alpha is a potent treatment option for inflammatory bowel disease (IBD). Dosing regimens in children are extrapolated from adult data using a fixed, weight-based dose, which is often not adequate. While clinical trials have focused on safety and efficacy, there is limited data on pharmacokinetic characteristics and immunogenicity of IFX in children. The objective was to provide a systematic overview of current literature on pharmacokinetic and immunogenicity of IFX in children with IBD, to assess the validity of current adult to pediatric dosing extrapolation.

METHODS

A literature search identified publications up to October 2018. Eligibility criteria were study population consisting of children and/or adolescents with IBD, report of IFX trough levels and/or antibodies-to IFX, full text article or abstract, article in English, and original data.

RESULTS

Initial electronic search yielded 2360 potentially relevant articles, with 1831 remaining after removal of duplicates. An additional search yielded another 202 potentially relevant articles. Of the 2033 retrieved articles, 2000 articles were excluded based on title, abstract, or eligibility criteria. Clearance of IFX was increased in young children and children with extensive disease, leading to lower trough levels after extrapolated dosing of 5 mg/kg, antibodies-to IFX emergence, and subsequent reduced efficacy.

CONCLUSIONS

Adult to pediatric weight-based dosing extrapolation is often inadequate. We provide several considerations for optimal dosing of IFX in children and adolescents with IBD.

A virtual clinic increases anti-TNF dose intensification success via a treat-to-target approach compared with standard outpatient care in Crohn's disease

BACKGROUND

Virtual clinics represent a novel model of care in inflammatory bowel disease. Their effectiveness in promoting high quality use of biologic therapy and facilitating a treat-to-target approach is unknown.

AIM

To evaluate clinical and process-driven outcomes in a virtual clinic compared to standard outpatient care amongst patients receiving intensified anti-TNF therapy for secondary loss of response.

METHODS

We performed a retrospective multi-centre, parallel, observational cohort study of Crohn's disease patients receiving intensified anti-TNF therapy for secondary loss of response. Objective assessments of disease activity and anti-TNF trough levels at secondary loss of response and during subsequent 6-month semesters, were compared longitudinally between virtual clinic and standard outpatient care cohorts. The primary endpoint was treatment success, with appropriateness of dose intensification, tight disease monitoring and treatment de-escalation representing secondary outcomes.

RESULTS

Of 149 patients with similar baseline characteristics, 69 were managed via a virtual clinic and 80 via standard outpatient care. There were higher rates of treatment success in the virtual clinic cohort (60.9 vs 35.0%, P < 0.002). Rates of appropriate dose intensification (82.6% vs 40.0%, P < 0.001), biomarker remission (faecal calprotectin P = 0.002), tight-disease monitoring (84.1% vs 28.8%, P < 0.001) and treatment de-escalation (21.3% vs 10.0%, P = 0.027) also favoured the virtual clinic cohort.

CONCLUSION

This study favoured a virtual clinic-led model-of-care over standard outpatient care in facilitating treatment success as part of an effective treat-to-target approach in Crohn's disease. A virtual clinic model-of-care also improved treatment outcomes and quality of use of intensified anti-TNF therapy through processes that promoted appropriate dose intensification and tight-disease monitoring, while encouraging more frequent dose de-escalation.

Infliximab levels and antibodies in IBD-related peripheral arthralgia

BACKGROUND

Extra-intestinal manifestations (EIM) are common in inflammatory bowel diseases (IBD) and may affect up to 40% of the patients during the course of the disease. Peripheral arthralgia (PA) is by far the most common EIM. To date, TNFα inhibitors are the most established treatment for EIMs in IBD. Infliximab (IFX) trough levels (TL) and anti-IFX antibodies (ATI) are correlated with multiple outcomes in IBD such as clinical response and remission, mucosal healing, fistular healing, and more. So far, a correlation between PA and IFX TL\ATI has not been evaluated.

METHODS

This retrospective study included IBD patients followed by the gastroenterology department of Sheba Medical Center. Patients with active PA at onset of IFX treatment were included. IFX TL and ATI were evaluated at week 6, 14, and 26 and correlated with PA persistence.

RESULTS

Forty patients (37 Crohn's and 3 ulcerative colitis) with IBD-related PA were included. The overall prevalence of PA was 55% (22/40), 42.5% (17/40), and 55% (22/40) after 6, 14, and 26 weeks, respectively. IFX trough drug levels were not associated with reported PA at week 6 [median, 11.8 μg/ml (IQR 6.6-15.5) vs 10.05 μg/ml (IQR 7.35-12.87), p = 0.56], week 14 [median, 4.7 μg/ml (IQR 2.3-7) vs 3.1 μg/ml (IQR 1.35-7.35), p = 0.55], and week 26 [median, 3 μg/ml (IQR 1.15-5.17) vs 3.4 μg/ml (IQR 0.13-6.75), p = 0.94]. Detectable ATI were significantly more prevalent in patients with PA than in patients without PA at week 26 [11/22 (50%) vs 3/18 (16.7%), p = 0.028].

CONCLUSIONS

In patients with IBD-related PA, ATI are associated with an increased risk of persistence of PA. No direct correlation was demonstrated between IFX TL and persistence of PA.

A User's Guide to De-escalating Immunomodulator and Biologic Therapy in Inflammatory Bowel Disease

De-escalation of immunomodulators and biologic agents in inflammatory bowel disease is frequently discussed with patients and must weigh the risk of continued medical therapy with the risk of disease recurrence. Risk factors for disease flare after withdrawal of inflammatory bowel disease medications such as disease activity at de-escalation, disease prognostic features, and prior course of disease have been identified predominately in retrospective studies, allowing for risk stratification of patients. This review evaluates the published literature regarding therapeutic de-escalation and provides a framework for physicians to apply this to clinical practice. Prospective trials are underway and planned, which should provide further insight into this treatment paradigm and better inform patient selection for this strategy.

Potential Utility of Therapeutic Drug Monitoring of Adalimumab in Predicting Short-Term Mucosal Healing and Histologic Remission in Pediatric Crohn's Disease Patients

BACKGROUND

Limited data exist regarding mucosal healing (MH) and therapeutic drug monitoring (TDM) in pediatric Crohn's disease (CD) patients treated with adalimumab (ADL). We aimed to investigate the associations between ADL trough levels (TLs) and MH, and between ADL TLs and histologic remission (HR) at 16 weeks from ADL treatment in pediatric CD patients.

METHODS

This was a prospective study on moderate-to-severe luminal pediatric CD patients receiving ADL. Ileocolonoscopies and biopsies, as well as clinical activity assessments, laboratory examinations, including tests for ADL TLs and antibody to ADL, were performed 16 weeks after ADL initiation. MH was defined as a Simple Endoscopic Score for CD of 0. HR was defined as the complete absence of microscopic inflammation.

RESULTS

Seventeen subjects (13 males, 4 females) were included. At 16 weeks from ADL initiation, 14 (82.4%), 8 (47.1%), and 4 (23.5%) patients achieved clinical remission, MH, and HR, respectively. ADL TLs were significantly higher in patients who achieved MH compared to those who did not (13.0 ± 6.5 vs. 6.2 ± 2.6 μ/mL, respectively; P = 0.023) and also significantly higher in patients who achieved HR compared to those who did not (17.9 ± 5.3 vs. 6.8 ± 2.5 μ/mL, respectively; P = 0.02). The optimal TL for predicting MH was 8.76 μ/mL.

CONCLUSION

Serum ADL TLs at 16 weeks were significantly higher in pediatric patients with CD who achieved MH and HR, respectively. TDM may guide in optimizing treatment efficacy and better target MH in the era of treat-to-target.

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.

Clinical Immunogenicity Risk Assessment Strategy for a Low Risk Monoclonal Antibody

This article provides a theoretical case-study risk assessment report for a low-risk monoclonal antibody (mAb) therapeutic. In terms of risk, there are considerations around risks to safety, but also risks regarding effects on pharmacokinetics (PK), pharmacodynamics (PD), and efficacy. Much of the discussion in this document is around the risk of immunogenicity incidence. A higher incidence of immunogenicity would necessitate a detailed review of the PK, efficacy and safety in anti-drug antibody (ADA) positive and ADA negative subjects, in order to evaluate potential effects. The publication is intended to provide a framework of some the current thought processes around assessing immunogenicity risk and for building strategies to mitigate those risks. For this example, we have created a hypothetical antibody, ABC-123, targeting a membrane protein on antigen presenting cells, for the treatment of rheumatoid arthritis (RA). This hypothetical antibody therapeutic is provided as an example for the purposes of risk assessment for a low risk molecule, although any application of similar approach would be case by case.

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.

Monitoring a Combination of Calprotectin and Infliximab Identifies Patients With Mucosal Healing of Crohn's Disease

BACKGROUND & AIMS

In the TAILORIX trial, no benefit could be shown by infliximab dose escalation based on pharmacokinetic (infliximab serum concentrations) and pharmacodynamic (biomarkers and symptoms) monitoring compared with dose escalation based on symptoms alone in patients with Crohn's disease (CD). We investigated whether integration of pharmacokinetic and pharmacodynamic monitoring can be used to evaluate responses to infliximab induction and maintenance therapy, based on findings from endoscopy.

METHODS

We performed a post hoc analysis of patients with CD included in a trial to test the effects of infliximab dose escalation, based on biomarkers and serum concentrations of infliximab, on symptoms (the Study Investigating Tailored Treatment With Infliximab for Active Crohn's Disease trial; n = 122). We analyzed data from this study to determine whether concentrations of biomarkers and serum concentrations of infliximab were associated with endoscopic outcomes (n = 116). The primary end points were endoscopic response (CD endoscopic index of severity decrease ≥50% from baseline), endoscopic remission (CD endoscopic index of severity, <3), and absence of ulcers at weeks 12 and 54 of infliximab treatment.

RESULTS

Infliximab trough concentrations greater than 23.1 mg/L at week 2 and greater than 10.0 mg/L at week 6 were associated with endoscopic remission at week 12 (positive predictive values, 72% and 76%; negative predictive values, 65% and 59%, respectively). During maintenance therapy, we found evidence for an exposure-response relationship only after dose escalation; trough concentrations greater than 10.6 mg/L were associated with the absence of ulcers at week 54 (positive predictive value, 49%; negative predictive value, 92%). Low fecal concentrations of calprotectin during therapy were associated with endoscopic response and remission (P < .05). Dose escalations increased trough concentrations of infliximab; persistent increase in fecal concentration of calprotectin, despite dose escalation, was associated with a lack of endoscopic response and remission. A significantly higher proportion of patients with antibodies to infliximab, identified by a drug-tolerant assay, dropped out of the study compared with patients without antibodies (P < .0001).

CONCLUSIONS

In a post hoc analysis of data from a trial to test the effects of infliximab dose escalation on symptoms, we found that during maintenance therapy, the combination of fecal concentration of calprotectin and trough concentration of infliximab can guide dose adjustment and increase the chances for endoscopic response and remission. ClinicalTrialsRegister.eu EudraCT no: 2011-003038-14.

Review article: determination of the therapeutic range for therapeutic drug monitoring of adalimumab and infliximab in patients with inflammatory bowel disease

BACKGROUND

Clinical application of therapeutic drug monitoring (TDM) to optimise anti-TNF therapies in patients with IBD depends upon target ranges.

AIMS

To review methodology used to determine therapeutic ranges and critically compare and contrast its application to infliximab and adalimumab.

METHODS

A systematic review was performed, and relevant literature was summarised and critically examined.

RESULTS

Upper limits of the therapeutic range are determined by toxicity, a plateau response and cost. Lower limits are determined by optimal concentration on the target of action in vitro and/or in vivo, or by correlation of drug levels with clinical efficacy using area-under-receiver-operator-curve (AUROC) analysis. In 43 studies, there were huge variations in time at which infliximab and adalimumab levels were measured, the end-points used (clinical remission to mucosal healing), the clinical setting (active disease vs maintenance phase) and the reason for TDM (proactive vs reactive). In the maintenance phase for infliximab, lower trough limits 2.8-5.7 µg/mL are reported depending upon end-points used, with consistent AUROC 0.68-0.77. Adalimumab TDM targets are even less consistent with a lower limit 5.9-11.8 µg/mL (AUROC 0.66-0.83) in some studies, but no cut-off can be identified that is significantly associated with outcome in others, related to inherent pharmacokinetic and pharmacodynamic differences, and heterogeneity of study design.

CONCLUSIONS

Evidence for exposure-response relationship is stronger for infliximab than adalimumab. Due to heterogeneity in settings for drug level measurements, therapeutic ranges vary. These factors need to be taken into account when interpreting the evidence and extending this to therapeutic strategies for IBD patients.

Serum Infliximab Cutoff trough Level Values for Maintaining Hematological Remission in Pediatric Inflammatory Bowel Disease

Background/Aims

Infliximab (IFX) often loses its therapeutic effect in initial responders with inflammatory bowel disease (IBD) over time. Low serum IFX trough levels (TLs) are linked to poor clinical response and outcomes. Maintenance of optimal therapeutic IFX concentrations is important for sustaining response and achieving good clinical outcomes. Measurement of serum IFX TLs is helpful for determining a further proper therapeutic plan. However, adequate therapeutic IFX TLs in pediatric IBD is uncertain. We aimed to identify the cutoff values for IFX TLs associated with laboratory response to IFX maintenance therapy.

Methods

Patients with pediatric IBD who had received IFX infusions between December 2008 and March 2015 at Samsung Medical Center were retrospectively investigated. We analyzed 239 blood samples that were collected from 103 pediatric patients. We measured IFX TLs at induction (6 and 14 weeks) and during maintenance therapy (>22 weeks, 8 weeks interval) by fluid-phase radioimmunoassays.

Results

A significant association was found between the erythrocyte sedimentation rate (ESR) and IFX TLs during maintenance (correlation coefficient, -0.11; p=0.0005). A cutoff value of 18 mm/hr for ESR was used to define higher levels. Receiver operating characteristic analysis identified optimal cutoff values: IFX TL >1.58 µg/mL (sensitivity 82% and specificity 73%).

Conclusions

Cutoff values are considered a prerequisite for further investigating the clinical usefulness of measurements of IFX in patients maintained with IFX treatment.

Factors Influencing Drug Disposition of Monoclonal Antibodies in Inflammatory Bowel Disease: Implications for Personalized Medicine

Monoclonal antibody (mAb) therapies have revolutionized the treatment of several chronic inflammatory diseases, including the inflammatory bowel diseases (IBD), Crohn's disease, and ulcerative colitis. While efficacious, responses to these therapies vary considerably from patient to patient, due in part to inter- and intra-individual variability in pharmacokinetics (PK) and drug exposure. The concept of personalized medicine to monitor drug exposure and to adjust dosing in individual patients is consequently gaining acceptance as a powerful tool to optimize mAb therapy for improved outcomes in IBD. This review provides a brief overview of the different mAbs currently approved or in development for the treatment of IBD, including their presumed mechanisms of action and PK properties. Specifically described are (1) the factors known to affect mAb PK and drug exposure in patients with IBD, (2) the value of population PK/pharmacodynamic (PD) modeling to identify and understand the influence of these factors on drug exposure and effect, and (3) the clinical evidence for the potential of therapeutic drug monitoring (TDM) to improve IBD outcomes in response to mAb-based therapy. Incorporation of PK/PD parameters into clinical decision support tools has the potential to guide therapeutic decision making and aid implementation of personalized medicine strategies in patients with IBD.

Immunomodulator use does not prevent first loss of response to anti-tumour necrosis factor alpha therapy in inflammatory bowel disease: long-term outcomes in a real-world cohort

BACKGROUND

Recent prospective studies suggest combination therapy with immunomodulators improves efficacy, but long-term data is limited.

AIM

To assess whether anti-tumour necrosis factor alpha (anti-TNF) monotherapy was associated with earlier loss of response (LOR) than combination therapy in a real-world cohort with long-term follow up.

METHODS

A retrospective audit was conducted of inflammatory bowel disease patients receiving anti-TNF therapy in a tertiary centre and specialist private practices. All patients with accurate data for anti-TNF commencement and adequate correspondence to determine end-points were included. Outcomes measured included time to first LOR, causes and biochemical parameters.

RESULTS

Two hundred and twenty-four patients were identified; 139 (62.1%) on combination therapy and 85 (37.9%) on monotherapy. Forty-five percent of patients had LOR during follow up until a maximum of 8.5 years; 59.4% on combination therapy and 40.6% on monotherapy (P = 0.533). The median time to LOR was not different between groups; 1069 days for combination therapy and 1489 days for monotherapy (P = 0.533). There was no difference in time to LOR between patients treated with different combination regimens or different anti-TNF agents.

CONCLUSION

In this large cohort of patients in a real-world setting, patients treated with anti-TNF monotherapy had similar rates of LOR as patients on anti-TNF combination therapy, at both short- and long-term follow up.

The potential value of blood monitoring of biologic drugs used in the treatment of rheumatoid arthritis

The advent of biological therapies has been a major therapeutic advance in rheumatology. Many patients now enjoy improved quality of life through better disease control. The number of therapies continues to grow both within drug class (including biosimilar drugs) and via new mechanisms. For the first time, nonbiological drugs such as small-molecule inhibitors (Janus kinase inhibitors) have shown clinical equivalence. However, clinical unmet need remains with up to a third of patients commenced on a biologic therapy having minimal or no response: (a) Generally, the first biologic used secures the best response, with likelihood of remission falling thereafter with successive therapies; (b) the success of strategy trials using biological therapies can be difficult to replicate in clinical practice due to a combination of patient factors and service limitations. Accordingly, ensuring optimization of initial treatment is an important consideration before switching to alternatives. Therapeutic drug monitoring (TDM) is the measurement of serum levels of a biologic drug with the aim of improving patient care. It is usually combined with detection of any antidrug antibodies that could neutralize the effect of the therapy. This technology has the potential to be a form of 'personalized medicine' by individualizing therapy, in particular, dosing and likelihood of sustained treatment response. It requires a clear relationship between drug dose, blood concentration and therapeutic effect. This paper will outline the technology behind TDM and unpack what we can learn from our colleagues in gastroenterology, where the adoption of TDM is at a more advanced stage than in rheumatology. It will explore and set out a number of clinical scenarios where rheumatologists might find TDM helpful in day-to-day practice. Finally, an outline is given of international developments, including regulatory body appraisals and guideline development.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Proactive Vs Reactive Therapeutic Drug Monitoring of Infliximab in Crohn's Disease: A Cost-Effectiveness Analysis in a Simulated Cohort

BACKGROUND

Therapeutic drug monitoring (TDM) is increasingly performed for Infliximab (IFX) in patients with Crohn's disease (CD). Reactive TDM is a cost-effective strategy to empiric IFX dose escalation. The cost-effectiveness of proactive TDM is unknown. The aim of this study is to assess the cost-effectiveness of proactive vs reactive TDM in a simulated population of CD patients on IFX.

METHODS

We developed a stochastic simulation model of CD patients on IFX and evaluated the expected health costs and outcomes of a proactive TDM strategy compared with a reactive strategy. The proactive strategy measured IFX concentration and antibody status every 6 months, or at the time of a flare, and dosed IFX to a therapeutic window. The reactive strategy only did so at the time of a flare.

RESULTS

The proactive strategy led to fewer flares than the reactive strategy. More patients stayed on IFX in the proactive vs reactive strategy (63.4% vs 58.8% at year 5). From a health sector perspective, a proactive strategy was marginally cost-effective compared with a reactive strategy (incremental cost-effectiveness ratio of $146,494 per quality-adjusted life year), assuming a 40% of the wholesale price of IFX. The results were most sensitive to risk of flaring with a low IFX concentration and the cost of IFX.

CONCLUSIONS

Assuming 40% of the average wholesale acquisition cost of biologic therapies, proactive TDM for IFX is marginally cost-effective compared with a reactive TDM strategy. As the cost of infliximab decreases, a proactive monitoring strategy is more cost-effective.

Higher anti-tumor necrosis factor levels are associated with perianal fistula healing and fistula closure in Crohn's disease

OBJECTIVE

Limited data are available regarding the relationship between anti-tumor necrosis factor (TNF) drug/antibody levels and perianal fistula outcomes in Crohn's disease. The aims of this study were to assess the relationship between maintenance anti-TNF levels and perianal fistula outcomes.

METHODS

This was a retrospective cross-sectional study of patients receiving maintenance adalimumab or infliximab therapy (minimum 24 weeks) for the treatment of Crohn's disease with associated perianal fistulas, who had anti-TNF drug/antibody levels (trough for infliximab) measured within 4 weeks of clinical assessment. The primary outcome was the association of anti-TNF levels with perianal fistula healing defined as the absence of drainage. The secondary outcome was the association of anti-TNF levels with complete perianal fistula closure.

RESULTS

A total of 64 patients (adalimumab, n = 35; infliximab, n = 29) were included. Patients with fistula healing had higher levels of anti-TNF vs. those without fistula healing (adalimumab: 12.6 vs. 2.7 μg/mL, P < 0.01; infliximab: 8.1 vs. 3.2 μg/mL, P < 0.01). Patients with fistula closure also had significantly higher anti-TNF levels vs. those without fistula closure (adalimumab: 14.8 vs. 5.7 μg/mL, P < 0.01; infliximab: 8.2 vs. 3.2 μg/mL, P < 0.01). For adalimumab, receiver operator characteristic analysis identified an optimum level of >6.8 μg/mL and >9.8 μg/mL for fistula healing and closure, respectively. For infliximab, receiver operator characteristic analysis identified an optimum trough level of >7.1 μg/mL for both fistula healing and closure.

CONCLUSION

Higher maintenance anti-TNF levels are associated with perianal fistula healing and closure in Crohn's disease.

Gender Differences and Other Factors Associated with Weight Gain Following Initiation of Infliximab: A Post Hoc Analysis of Clinical Trials

BACKGROUND

In our clinical practice, women often report excess weight gain with infliximab (IFX) use. There are currently no studies investigating weight gain after antitumor necrosis factor therapy in patients with inflammatory bowel disease. The objective of this study was to evaluate the association of clinical factors, with a particular focus on sex and weight gain in patients with moderate to severe Crohn's disease (CD) or ulcerative colitis (UC) initiating IFX.

METHODS

Data was extracted from ACCENT I, ACCENT II, ACT 1, and SONIC; included patients received IFX for induction or maintenance of remission of CD or UC. Patients treated with azathioprine (IFX 0 mg/kg) were included as controls. Baseline demographics, clinical characteristics, and weight at each follow-up for the study duration were collected. In addition to descriptive statistics, adjusted mixed effects models were used to test the association between clinical variables and weight gain.

RESULTS

There were 1273 patients included for analysis; the majority was white (91%), with CD (81%), and half of patients (50%) were women. Upon univariate analysis, IFX dose, African American race, diagnosis of CD, elevated C-reactive protein, and low hematocrit and albumin were associated with weight gain (P < 0.001). Upon adjusted analysis, sex was significantly associated with weight gain (P = 0.009), with women experiencing a lower percentage increase from baseline weight than men (3.9% increase vs 4.3% increase).

CONCLUSIONS

When starting IFX, those with markers of severe disease and with a diagnosis of CD are likely to gain more weight. Adjusting for confounding variables, women actually gain less weight than men after IFX treatment, although this difference is not clinically relevant.

Improving Post-induction Antitumor Necrosis Factor Therapeutic Drug Monitoring in Pediatric Inflammatory Bowel Disease

OBJECTIVES

Adequate serum drug levels of tumor necrosis factor-alpha inhibitors (anti-TNF) have been shown to improve outcomes in patients with inflammatory bowel disease. We aim to describe the quality improvement (QI) methods used at our institution to improve post-induction therapeutic drug monitoring (TDM) in children initiating anti-TNF therapy (infliximab and adalimumab) and describe the frequency of subtherapeutic anti-TNF levels.

METHODS

Beginning in February 2016, all patients initiating anti-TNF therapy were identified and tracked. Interventions to improve TDM, including the initiation of therapy plans for infliximab, real-time reminders for practitioners, and scheduling modifications for those initiating anti-TNF therapies were implemented using the Institute for Healthcare Improvement Plan-Do-Study-Act cycle approach. Statistical process control charts were used to demonstrate improvement over time. Anti-TNF levels and presence of antidrug antibodies were also recorded.

RESULTS

Using QI methodology, we improved post-induction anti-TNF TDM from a baseline of 43% in 2015 to >80% by the end of 2017, with sustained improvement. Infliximab post-induction TDM improved from a baseline of 59% to 82%, whereas adalimumab post-induction TDM improved from baseline of 14% to 79%. In total, 36% of all anti-TNF post-induction levels were <5 μg/mL, with nearly 60% of post-induction infliximab levels being <5 μg/mL.

CONCLUSIONS

Through incremental QI approaches, we improved the utilization of anti-TNF post-induction TDM with sustained improvement, approaching our goal of 90%. Subtherapeutic post-induction infliximab levels were common, indicating a strong need for anti-TNF TDM and an opportunity for dose optimization.

Model-Based Therapeutic Drug Monitoring of Infliximab Using a Single Serum Trough Concentration

BACKGROUND AND OBJECTIVES

The pharmacokinetics of infliximab are highly variable and influence clinical response in chronic inflammatory diseases. The goal of this study was to build a Bayesian model allowing predictions of upcoming infliximab concentrations and dosing regimen adjustment, using only one concentration measurement and information regarding the last infliximab infusion.

METHODS

This retrospective study was based on data from 218 patients treated with infliximab in Tours University Hospital who were randomly assigned to learning (two-thirds) or validation (one-third) data subsets. One-compartment pharmacokinetic and time since last dose (TLD) models were built and compared using learning and validation subsets. From these models, Bayesian pharmacokinetic and TLD models using one concentration measurement (1C-PK and 1C-TLD) were designed. The predictive performances of the 1C-TLD model were tested on two external validation cohorts.

RESULTS

Pharmacokinetic and TLD models described the data satisfactorily and provided accurate parameter estimations. Comparable predictions of infliximab concentrations were obtained from pharmacokinetic versus TLD models, as well as from Bayesian 1C-PK versus 1C-TLD models. The 1C-TLD model showed satisfactory prediction of future infliximab concentrations and provided satisfactory predictions of infliximab steady-state concentration for up to three upcoming visits after a blood sample.

CONCLUSIONS

Accurate individual concentration predictions can be obtained using a single infliximab concentration measurement and information regarding only the last infusion. The 1C-TLD model may help to optimize the dosing regimen of infliximab in routine therapeutic drug monitoring.