Concomitant Use of Immunomodulators Affects the Durability of Infliximab Therapy in Children With Crohn's Disease

Precise infliximab exposure and pharmacodynamic control to achieve deep remission in paediatric Crohn's disease (REMODEL-CD): study protocol for a multicentre, open-label, pragmatic clinical trial in the USA

INTRODUCTION

The only biologic therapy currently approved to treat moderate to severe Crohn's disease in children (<18 years old) are those that antagonise tumour necrosis factor-alpha (anti-TNF). Therefore, it is critically important to develop novel strategies that maximise treatment effectiveness in this population. There is growing evidence that rates of sustained corticosteroid-free clinical remission, endoscopic healing and drug durability considerably improve when patients receive early anti-TNF dose optimisations guided by reactive or proactive therapeutic drug monitoring and pharmacodynamic monitoring. In response, our team has developed a personalised and scalable infliximab dosing intervention that starts with dose selection and continues throughout maintenance to optimise drug exposure. We hypothesise that a precision dosing strategy starting from induction and targeting dose-specific pharmacokinetic and pharmacodynamic endpoints throughout therapy will significantly improve outcomes compared with a conventional dosing strategy.

METHODS AND ANALYSIS

Conduct a clinical trial to assess rates of deep remission between Crohn's disease patients receiving infliximab with precision dosing (n=90) versus conventional care (n=90). Patients (age 6-22 years) will be recruited from 10 medical centres in the USA. Each centre has been selected to provide either precision dosing or conventional care dosing. Precision dosing includes the use of a clinical decision support tool (RoadMAB) from the start of infliximab to achieve specific (personalised) trough concentrations and specific pharmacodynamic targets (at doses 3, 4 and 6). Conventional care includes the use of a modified infliximab starting dose (5 or 7.5 mg/kg based on the pretreatment serum albumin) with a goal to achieve maintenance trough concentrations of 5-10 µg/mL. The primary endpoint is year 1 deep remission defined as a combination of clinical remission (paediatric Crohn's disease activity index<10 (child) or a Crohn's disease activity index<150 (adults)), off prednisone>8 weeks and endoscopic remission (simple endoscopic severity-Crohn's disease≤2).

ETHICS AND DISSEMINATION

). The study protocol has been approved by the Cincinnati Children's Hospital Medical Centre Institutional Review Board. Study results will be disseminated in peer-reviewed journals and presented at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05660746.

Comparison of endoscopic healing and durability between infliximab originator and CT-P13 in pediatric patients with inflammatory bowel disease

Background and aims

Favourable clinical data were published on the efficacy of CT-P13, the first biosimilar of infliximab (IFX), in pediatric inflammatory bowel disease (IBD); however, few studies have compared the effect on endoscopic healing (EH) and drug retention rate between the IFX originator and CT-P13. Therefore, we aimed to compare EH and the drug retention rate between the IFX originator and CT-P13.

Methods

Children with Crohn's disease (CD) and ulcerative colitis (UC)/IBD-unclassified (IBD-U) at 22 medical centers were enrolled, with a retrospective review conducted at 1-year and last follow-up. Clinical remission, EH and drug retention rate were evaluated.

Results

We studied 416 pediatric patients with IBD: 77.4% had CD and 22.6% had UC/IBD-U. Among them, 255 (61.3%) received the IFX originator and 161 (38.7%) received CT-P13. No statistically significant differences were found between the IFX originator and CT-P13 in terms of corticosteroid-free remission and adverse events. At 1-year follow-up, EH rates were comparable between them (CD: P=0.902, UC: P=0.860). The estimated cumulative cessation rates were not significantly different between the two groups. In patients with CD, the drug retention rates were 66.1% in the IFX originator and 71.6% in the CT-P13 group at the maximum follow-up period (P >0.05). In patients with UC, the drug retention rates were 49.8% in the IFX originator and 56.3% in the CT-P13 group at the maximum follow-up period (P >0.05).

Conclusions

The IFX originator and CT-P13 demonstrated comparable therapeutic response including EH, clinical remission, drug retention rate and safety in pediatric IBD.

Factors that influence infliximab biosimilar trough levels in the pediatric inflammatory bowel disease population

BACKGROUND

The pharmacokinetics and pharmacodynamics of biosimilar infliximab (IFX-BioS) in pediatric inflammatory bowel disease (IBD) are poorly investigated. The aim of this study was to investigate factors predicting IFX-BioS trough levels (TLs).

RESEARCH DESIGN AND METHODS

IBD children with an indication to start IFX-BioS were included in this prospective observational study (January 2021-June 2022). TLs were measured at the 4th and 6th infusions and correlated with several covariates.

RESULTS

A total of 110 TLs in 55 children were included. The multivariate linear regression model at the 4th infusion found a positive correlation between TLs and age at diagnosis (B:1.950, 95% CI: [0.019, 3.882], p = 0.048) and IFX-BioS dose/kg (B:1.962, 95% CI: [0.238, 3.687], p = 0.029), and a negative correlation with clinical scores (B:-0.401, 95% CI: [-0.738, -0.064], p = 0.023). At the 6th infusion, female gender (B:6.887, 95% CI: [0.861, 12.913], p = 0.029), hemoglobin (B:1.853, 95% CI: [0.501, 3.204], p = 0.011), and IFX-BioS dose/kg (B:1.792, 95% CI: [0.979, 2.605], p < 0.001) were found to be positively correlated to TLs. No association between combined clinical and biochemical remission and TLs was found.

CONCLUSIONS

This study discovered some predictors for IFX-BioS TLs in IBD children. Knowledge of predictive factors could help physicians choose the best dosing regimen.

Anti-infliximab antibodies and low infliximab levels correlate with drug discontinuation in pediatric inflammatory bowel disease

BACKGROUND

Infliximab (IFX) use is limited by loss of response often due to the development of anti-IFX antibodies and low drug levels.

METHODS

We performed a single center prospective observational cohort study of pediatric and young adult subjects with inflammatory bowel disease (IBD) on IFX with over 3 years of follow-up. Infliximab levels (IFXL) and antibodies to infliximab (ATI) were measured throughout the study. Subjects were followed until IFX was discontinued.

RESULTS

We enrolled 219 subjects with IBD (184: Crohn's disease; 33: Ulcerative colitis; and 2 Indeterminant colitis; 84 female, median age 14.4 years, 37% on concomitant immunomodulator). Nine hundred and nineteen serum samples (mean 4.2 ± 2.1 per patient) were tested for IFXL and ATI. During the study, 31 (14%) subjects discontinued IFX. Sixty patients had ATI. Twenty-two of those 60 patients with ATI discontinued IFX; 14 of 31 patients who discontinued IFX had detectable ATI at study onset. The combination of ATI and IFXL < 5 µg/mL at study entry was associated with the highest risk of drug discontinuation (hazard ratios [HR] ATI 4.27 [p < 0.001] and IFXL < 5 µg/mL [HR]: 3.2 p = 0.001). Patients with IFXL 5-10 µg/mL had the lowest rate of discontinuation (6%). IFX dose escalation eliminated ATI in 21 of 60 subjects.

CONCLUSIONS

ATI is a strong predictor of needing to stop IFX use and inversely correlates with IFXL. Detection of ATI during therapeutic drug monitoring postinduction but also periodically during maintenance therapy identifies individuals who may benefit from IFX dose escalation and/or the addition of an immunomodulator, as these interventions may reduce or eliminate ATI.

Durability of Adalimumab and Infliximab in Children With Crohn's Disease: A Nationwide Comparison From the epi-IIRN Cohort

BACKGROUND

In a nationwide cohort, we aimed to compare the durability of infliximab and adalimumab as first biologic treatment in children with Crohn's disease (CD), stratified as combotherapy or monotherapy.

METHODS

We used data from the epi-IIRN cohort that includes all patients with inflammatory bowel diseases in Israel. Durability was defined as consistent treatment without surgery or treatment escalation. All comparisons followed stringent propensity-score matching in Cox proportional hazard models.

RESULTS

Of the 3487 children diagnosed with CD since 2005, 2157 (62%) received biologics (1127 [52%] infliximab, 964 [45%] adalimumab and 52 [2%] vedolizumab as first biologic), representing a higher proportion than that among adults diagnosed during the same time period (5295 of 15 776 [34%]; P < .001). Time from diagnosis to initiation of biologic was shorter in pediatric-onset compared with adult-onset disease (median time during the last 3 years was 2.7 months [interquartile range 1.2-5.4] vs 5.2 months [2.6-8.9]; P < .001). The durability of adalimumab monotherapy after 1 and 5 years from initiation of treatment was better than infliximab monotherapy (79%/54% vs 67%/37%, respectively; n = 452 matched children; hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.3-2.3; P < .001), while in those treated with combotherapy, durability was similar (94%/66% with infliximab vs 90%/54% with adalimumab; n = 100; HR, 1.7; 95% CI, 0.9-3.3; P = .1). Durability was higher in children treated with infliximab combotherapy vs infliximab monotherapy (87%/45% vs 75%/39%; n = 440; HR, 1.4; 95% CI, 1.1-1.8; P = .01). The durability of adalimumab monotherapy was similar to infliximab combotherapy (83%/53% vs 89%/56%, respectively; n = 238; HR, 0.9; 95% CI, 0.7-1.2; P = .4).

CONCLUSION

Our results support using adalimumab monotherapy as a first-line biologic in children with CD. When infliximab is used, combotherapy may be advantageous over monotherapy.

The Future of Advanced Therapies for Pediatric Crohn's Disease

Pediatric Crohn's disease commonly presents with moderate-to-severe intestinal inflammation with a greater risk of complications if remission is not achieved. Anti-tumor necrosis factor therapies have offered the possibility of deep and durable remission; however, many children do not respond or no longer respond over time. Further, some children do not require broader systemic immunosuppression to achieve remission and are better served by an alternative treatment strategy. Proper utilization of advanced biologic and small-molecule therapies, which have become available for adult patients since anti-tumor necrosis factor medications, is paramount for tighter disease control for a large proportion of children. Newer advanced therapies such as anti-integrin and anti-interleukin biologics, and several small-molecule agents capitalize on various mechanisms through narrower immunologic targets and reduced immunogenicity. Given limited regulatory approvals of these agents for use in children with Crohn's disease, clinicians continue to rely on data extrapolated from clinical trials in adult patients, sparse pediatric studies, and a growing real-world experience for treatment selection and optimization. In this article, we discuss currently available treatment options, pipeline drugs, and relevant data as they pertain to some of the most pressing clinical challenges faced in treating pediatric Crohn's disease.

Precision Dosing of Anti-TNF Therapy in Pediatric Inflammatory Bowel Disease

PURPOSE OF THE REVIEW

This review focuses on recent advancements in anti-TNF therapeutic drug monitoring (TDM), pharmacogenetics and personalized drug selection for children with inflammatory bowel disease (IBD).

RECENT FINDINGS

Several real-world studies and one clinical trial in children have demonstrated that proactive TDM, targeting higher exposure concentrations (> 5 µg/mL), can improve disease remission rates and enhance durability of the anti-TNF biologics. Recent data from both adult and pediatric IBD patients have revealed an association between a genetic polymorphism (HLA-DQA1*05) and the development of auto-drug antibodies. The impact of this association on clinical outcomes, considering more routine use proactive TDM and dose optimization in children, is still under investigation. Additionally, recent studies have identified potential inflammatory signatures and biomarkers that may serve as companion diagnostics for anti-TNF biologics. The effective management of anti-TNF therapies in children with IBD requires evidence-based precision dosing strategies, including routine TDM and proactive pharmacodynamic assessments.

Efficacy and Safety of Anti-Tumor Necrosis Factor Alpha in Very Early Onset Inflammatory Bowel Disease

BACKGROUND

Very early onset inflammatory bowel disease (VEOIBD) is defined as disease onset in patients younger than 6 years. Challenges in treatment of VEOIBD include lack of approved therapies and increased incidence of monogenic immunodeficiencies. We report on patterns of anti-TNF use, efficacy, and safety in a large cohort of patients with VEOIBD.

METHODS

Very early onset inflammatory bowel disease patients receiving care at a single center were prospectively enrolled in a data registry and biorepository starting in 2012. Whole exome sequencing was available to all patients. Clinical data including IBD medication use and response were extracted from the medical record. We examined antitumor necrosis factor (anti-TNF) cumulative exposure and time to failure and evaluated the effect of covariates on anti-TNF failure using Cox proportional hazard regression.

RESULTS

In this cohort of 216 VEOIBD patients with median 5.8-year follow-up, 116 (53.7%) were TNF-exposed. Sixty-two TNF-exposed patients (53.4%) received their first dose at younger than 6 years. Cumulative exposure to anti-TNF was 23.6% at 1 year, 38.4% at 3 years, and 43.4% at 5 years after diagnosis. Cumulative exposure was greater in patients with Crohn's disease (P = .0004) and in those diagnosed in 2012 or later (P < .0001). Tumor necrosis factor failure occurred in 50.9% of those exposed. Features predictive of anti-TNF failure included ulcerative colitis/IBD-unclassified (hazard ratio, 1.94; P = .03), stricturing (hazard ratio, 2.20; P = .04), and younger age at diagnosis (hazard ratio, 1.25; P = .01). Adverse events occurred in 22.6% of infliximab-exposed and 14.3% of adalimumab-exposed.

CONCLUSIONS

Efficacy and safety of anti-TNFs in VEOIBD is comparable to what has previously been reported in older patients.

Dose escalation of adalimumab as a strategy to overcome anti-drug antibodies: A case report of infantile-onset inflammatory bowel disease

BACKGROUND

Treatment of infantile-onset inflammatory bowel disease (IO-IBD) is often challenging due to its aggressive disease course and failure of standard therapies with a need for biologics. Secondary loss of response is frequently caused by the production of anti-drug antibodies, a well-known problem in IBD patients on biologic treatment. We present a case of IO-IBD treated with therapeutic drug monitoring (TDM)-guided high-dose anti-tumor necrosis factor therapy, in which dose escalation monitoring was used as a strategy to overcome anti-drug antibodies.

CASE SUMMARY

A 5-mo-old boy presented with a history of persistent hematochezia from the 10th d of life, as well as relapsing perianal abscess and growth failure. Hypoalbuminemia, anemia, and elevated inflammatory markers were also present. Endoscopic assessment revealed skip lesions with deep colic ulcerations, inflammatory anal sub-stenosis, and deep fissures with persistent abscess. A diagnosis of IO-IBD Crohn-like was made. The patient was initially treated with oral steroids and fistulotomy. After the perianal abscess healed, adalimumab (ADA) was administered with concomitant gradual tapering of steroids. Clinical and biochemical steroid-free remission was achieved with good trough levels. After 3 mo, antibodies to ADA (ATA) were found with undetectable trough levels; therefore, we optimized the therapy schedule, first administering 10 mg weekly and subsequently up to 20 mg weekly (2.8 mg/kg/dose). After 2 mo of high-dose treatment, ATA disappeared, with concomitant high trough levels and stable clinical and biochemical remission of the disease.

CONCLUSION

TDM-guided high-dose ADA treatment as a monotherapy overcame ATA production. This strategy could be a good alternative to combination therapy, especially in very young patients.

Managing pediatric Crohn's disease: recent insights

INTRODUCTION

Children and adolescents with Crohn's disease present unique challenges due to extensive disease at diagnosis and the effect of bowel inflammation on growth. Historical approaches with corticosteroids and immunomodulators are far less effective than early treatment with anti-TNF biologics.

AREAS COVERED

This review covers recent literature delineating the crucial role of early anti-TNF therapy in the treatment of moderate- to- severe Crohn's disease in children and adolescents. The potential risks and benefits of concomitant immunomodulators are discussed, along with therapeutic anti-TNF drug monitoring, and reassessment by endoscopy and cross-sectional imaging to evaluate success beyond symptom control.

EXPERT OPINION

Standard of care therapy for moderate-to-severe pediatric Crohn's disease now entails precision dosing of anti-TNF therapy with periodic reassessment of bowel inflammation. The role of dietary modification continues to evolve. Current and future efforts need to be directed to elucidating ways to predict response to anti-TNF therapy and quickly changing to agents with other mechanisms of action when needed. Inordinate regulatory delays in approval of new therapies approved for adults continue to handicap pediatric clinicians and frequently limits their treatment choices, or forces them to give medications "off label." Only a concerted effort by clinicians, pharma, and regulators will improve this situation.

Infliximab vs adalimumab: Points to consider when selecting anti-tumor necrosis factor agents in pediatric patients with Crohn’s disease

Biologic agents with various mechanisms against Crohn’s disease (CD) have been released and are widely used in clinical practice. However, two anti-tumor necrosis factor (TNF) agents, infliximab (IFX) and adalimumab (ADL), are the only biologic agents approved by the Food and Drug Administration for pediatric CD currently. Therefore, in pediatric CD, the choice of biologic agents should be made more carefully to achieve the therapeutic goal. There are currently no head-to-head trials of biologic agents in pediatric or adult CD. There is a lack of accumulated data for pediatric CD, which requires the extrapolation of adult data for the positioning of biologics in pediatric CD. From a pharmacokinetic point of view, IFX is more advantageous than ADL when the inflammatory burden is high, and ADL is expected to be advantageous over IFX in sustaining remission in the maintenance phase. Additionally, we reviewed the safety profile, immunogenicity, preference, and compliance between IFX and ADL and provide practical insights into the choice of anti-TNF therapy in pediatric CD. Careful evaluation of clinical indications and disease behavior is essential when prescribing anti-TNF agents. In addition, factors such as the efficacy of induction and maintenance of remission, safety profile, immunogenicity, patient preference, and compliance play an important role in evaluating and selecting treatment options.

Medical Management of Pediatric Inflammatory Bowel Disease (PIBD) in the Asia Pacific Region: A Position Paper by the Asian Pan-Pacific Society for Pediatric Gastroenterology, Hepatology, and Nutrition (APPSPGHAN) PIBD Working Group

Pediatric inflammatory bowel disease (PIBD) is rising rapidly in many industrialised and affluent areas in the Asia Pacific region. Current available guidelines, mainly from Europe and North America, may not be completely applicable to clinicians caring for children with PIBD in this region due to differences in disease characteristics and regional resources constraints. This position paper is an initiative from the Asian Pan-Pacific Society for Pediatric Gastroenterology, Hepatology and Nutrition (APPSPGHAN) with the aim of providing an up-to-date, evidence-based approach to PIBD in the Asia Pacific region, taking into consideration the unique disease characteristics and financial resources available in this region. A group of pediatric gastroenterologists with special interest in PIBD performed an extensive literature search covering epidemiology, disease characteristics and natural history, management and monitoring. Gastrointestinal infections, including tuberculosis, need to be excluded before diagnosing IBD. In some populations in Asia, the Nudix Hydrolase 15 (NUD15) gene is a better predictor of leukopenia induced by azathioprine than thiopurine-S-methyltransferase (TPMT). The main considerations in the use of biologics in the Asia Pacific region are high cost, ease of access, and potential infectious risk, especially tuberculosis. Conclusion: This position paper provides a useful guide to clinicians in the medical management of children with PIBD in the Asia Pacific region.

Early Infliximab Clearance Predicts Remission in Children with Crohn's Disease

BACKGROUND AND AIMS

Children with Crohn's disease have lower response rates to infliximab, lower infliximab levels, and higher infliximab clearance on weight-based dosing than adults. We hypothesize infliximab clearance is a predictive of later outcomes on infliximab in children with Crohn's disease.

METHODS

In this single-center retrospective study, data were collected from charts on diagnosis, anthropometry, routine labs, infliximab therapeutic drug monitoring, infliximab dosing, disease activity, and other treatments. With these data we generated a population pharmacokinetic model using non-linear mixed effects modeling and calculated infliximab clearance for each patient over time. Patients were classified as in remission, responder-only or non-responder at 5, 10 and 16 months. Regression and ROC analyses were used to assess for early predictors of remission and response to infliximab.

RESULTS

Eighty-five subjects were included, with a median follow-up of 22.3 months (IQR 10.1-36.8). Our pharmacokinetic model showed infliximab clearance was positively associated with CRP and weight, while negatively associated with albumin. In regression analyses, early infliximab clearance was the only significant, consistent predictor of remission. A 0.1 L/day increase in infliximab clearance predicted remission with an OR between 0.179 and 0.426. Differences in dosing did not account for differences in outcome. Infliximab clearance alone had moderate predictive accuracy of remission, with an AUC between 0.682 and 0.738.

CONCLUSIONS

Early infliximab clearance is strongly associated with remission in children with Crohn's disease. It may be useful as a marker of response in proactive therapeutic drug monitoring to guide early dose optimization and/or changes in treatment for betterment of long-term outcomes.

Drug-Related Adverse Events Necessitating Treatment Discontinuation in Pediatric Inflammatory Bowel Disease Patients

OBJECTIVES

Inflammatory bowel disease (IBD) requires long-term drug therapy in most patients, posing a risk for adverse drug events with the need for discontinuation. In this study, we investigated adverse events (AE) necessitating drug discontinuation in pediatric and adolescent IBD patients.

METHODS

We used data prospectively collected from IBD patients below the age of 18 enrolled in the Swiss Inflammatory Bowel Disease Cohort Study (SIBDCS), namely demographic variables, medical characteristics, drug treatments, and related AE. We analyzed the frequency, type, and risk factors for AE necessitating drug discontinuation.

RESULTS

A total of 509 pediatric IBD patients fulfilled the inclusion criteria of which 262 (51.5%) were diagnosed with Crohn disease (CD), 206 (40.5%) with ulcerative colitis (UC), and 41 (8%) with IBD-unclassified (IBD-U). In total, 132 (25.9%) presented with at least 1 drug-related AE that required drug cessation. Immunomodulators [methotrexate 29/120 (24.2%), azathioprine 57/372 (15.3%)] followed by tumor necrosis factor (TNF)-alpha antagonists [adalimumab 8/72 (11.1%), infliximab 22/227 (9.7%)] accounted for the highest proportions of AE necessitating treatment discontinuation. Treatment schemes with at least 3 concomitant drugs significantly amplified the risk for development of drug-related AE [odds ratio = 2.50, 95% confidence interval (1.50-4.17)] in all pediatric IBD patients.

CONCLUSIONS

Drug-related AE necessitating discontinuation are common in pediatric and adolescent IBD patients. Caution needs to be taken in the case of concomitant drug use.

Long-Term Outcomes With Adalimumab Therapy in Pediatric Crohn Disease: Associations With Adalimumab Exposure

BACKGROUND/AIMS

Pediatric Crohn disease (CD) treatment goals have evolved. Among children receiving adalimumab (ADA) we examined long-term durability of clinical remission, linear growth, and associations of trough concentration (TC) with biomarker, endoscopic and imaging outcomes.

METHODS

Single-center retrospective study. Pediatric CD activity index, C-reactive protein, fecal calprotectin, and height measured longitudinally. Discontinuation due to secondary loss of response (LOR) was assessed using Cox proportional hazards model. Associations between TC and clinical and biomarker remission, endoscopic and magnetic resonance imaging (MRI) improvements were assessed using Cox regression with time-dependent covariates.

RESULTS

Between January 2007 and June 2018, 213 children (median age 14.1 years (interquartile range [IQR] 12.5-15.7) 65% males) initiated ADA. One hundred and seventy-four (82%) achieved clinical remission (PCDAI < 10). During 24.8 (IQR 15.6-38.4) months follow-up, 26 (15%) discontinued ADA due to LOR, and 10 (6%) due to adverse events. Being anti-tumor necrosis factor (TNF) naïve and inflammatory behavior associated with increased likelihood of clinical remission (odds ratio [OR] 2.39, P = 0.033, and 3.13, P = 0.013, respectively) and with decreased LOR (hazard ratio [HR] 0.3, P = 0.002, and HR 0.35, P = 0.01, respectively). Cumulative LOR among 135 anti-TNF naïve patients: 0%, 8%, 15% within 1, 2, 3 years, similarly durable with mono- and immunomodulator combination therapy. Among pre-/early pubertal children mean height (-0.82) normalized to -0.07. TC consistently >7.5 ug/mL was associated with durable clinical remission (HR = 17.24, P < 0.001); TC >10 ug/mL with durable biomarker remission (HR = 6.56, P < 0.001) and endoscopic (OR 10.4, P = 0.002) and MRI (OR 7.6, P = 0.001) improvements.

CONCLUSION

ADA monotherapy maintains durable clinical remission. Biomarker remission, mucosal and transmural improvements were associated with greater ADA exposure.

Risk of consecutive immunogenic failure in switchers of anti-tumor necrosis factor alpha among patients with inflammatory bowel diseases

BACKGROUND

Evidence regarding the risk of immunogenicity in patients with inflammatory bowel disease (IBD) who switched anti-tumor necrosis factor alpha (anti-TNFα) therapies to a subsequent anti-TNFα (either infliximab or adalimumab) is conflicting. We aimed to assess the risk of consecutive immunogenicity to anti-TNFα in a large cohort of patients.

METHODS

This was a multicenter retrospective study. Medical records of adult and pediatric IBD switchers who had pharmacokinetic data for both agents between 2014 and 2020 were retrieved. Data including age, sex, disease type, duration of therapies, and concomitant use of immunomodulators (IMMs) were recorded.

RESULTS

Overall, 164 patients were included [52% female; 88% Crohn's disease; mean age = 24.4 ± 14.6 years; 108 (66%) switched from infliximab to adalimumab and 56 (34%) vice versa]; 120 (73.1%) patients switched due to an immunogenic failure. Among patients switching therapy from infliximab to adalimumab due to an immunogenic failure immunogenicity to infliximab was significantly associated with consecutive immunogenicity to adalimumab (p = 0.026). Forthy four out of 120 patients (36.6%) with an immunogenic failure to the first anti-TNFα started an IMM with the second anti-TNFα. This combination with IMM was not associated with reduction of consecutive immunogenicity (p = 0.31), but it was associated with longer drug retention (p = 0.007). Multivariate analysis demonstrated that older age at second anti-TNFα, adjusted to the chronology of therapy and sex, was associated with increased immunogenicity to the second anti-TNFα.

CONCLUSION

Patients with IBD who switch from infliximab to adalimumab following an immunogenic failure are at increased risk for consecutive immunogenicity to adalimumab. IMM use after a switch prolongs drug retention.

Proactive therapeutic drug monitoring of adalimumab for pediatric Crohn's disease patients: A cost-effectiveness analysis

BACKGROUND AND AIM

Recent clinical findings showed proactive therapeutic drug monitoring (TDM) of adalimumab (ADL) to improve sustained remission rate in pediatric patients with Crohn's disease (CD). The present study aimed to evaluate the potential cost-effectiveness of proactive versus reactive TDM of ADL in pediatric patients with CD from the perspective of the US health-care provider.

METHODS

A Markov model was constructed to estimate outcomes of proactive versus reactive TDM of ADL in a hypothetical cohort of pediatric CD patients who were in remission on ADL maintenance treatment. Model inputs were derived from published literature and public data. Model outcomes included CD-related direct medical cost and quality-adjusted life-years (QALYs). Sensitivity analyses were performed to examine the robustness of base-case results.

RESULTS

When compared with the reactive TDM group, the proactive TDM group saved 0.1960 QALYs at lower cost by USD2021 over a 3-year time frame in base-case analysis. One-way sensitivity analysis showed the ADL drug cost to be the most influential factor. Probabilistic sensitivity analysis of 10 000 Monte-Carlo simulations found the proactive TDM group to gain 0.1958 QALYs (95% confidence interval [CI] 0.1950-0.1966; P < 0.001) and save USD2037 (95%CI USD1943-2131; P < 0.001).

CONCLUSIONS

Proactive TDM for ADL seems to gain higher QALYs at lower cost in pediatric CD patients.

Infliximab, Immunomodulators and Treatment Failures in Paediatric and Adolescent Patients with Crohn's Disease: a Nationwide Cohort Study

BACKGROUND AND AIMS

In paediatric patients with Crohn's disease, the role of combination therapy, infliximab plus immunomodulators [thiopurine or methotrexate], is debated and data are sparse. We examined whether infliximab plus immunomodulators, compared to infliximab therapy alone, reduces the risk of treatment failure measured by intestinal surgery or switching type of anti-tumour necrosis factor [TNF] α agent within 24 months.

DESIGN

Using Danish registries, we identified patients with Crohn's disease, aged ≤ 20 years at the time of the first infliximab treatment, and retrieved data on their co-medications. We used Cox regression models to examine surgery or switching type of anti-TNFα agent from January 1, 2003 to December 31, 2015.

RESULTS

We included 581 patients. The 2-year cumulative percentage of surgery was 8.5% among patients receiving combination therapy and 14.5% in those receiving infliximab alone. The adjusted 2-year hazard ratio [HR] of surgeries was 0.53 (95% confidence interval [CI] 0.32-0.88) in patients receiving combination therapy, compared to patients receiving infliximab alone. When examining a switch of anti-TNFα we included 536 patients. Within 2 years, 18.3% experienced a switch among patients receiving combination therapy and 24.8% in patients treated with infliximab alone, corresponding to an adjusted HR of 0.66 [95% CI 0.45-0.97] in patients receiving combination therapy.

CONCLUSIONS

The HR of intestinal surgeries and the risk of a switch to another anti-TNFα was reduced in paediatric and adolescent patients receiving combination therapy, compared to patients receiving only infliximab. These results suggest a benefit for infliximab therapy combined with immunomodulators, but these need to be confirmed in data with additional clinical information.

Is It Useful to Monitor Thiopurine Metabolites in Pediatric Patients with Crohn's Disease on Combination Therapy? A Multicenter Prospective Observational Study

BACKGROUND

The additional value of azathioprine concomitant treatment on infliximab pharmacokinetics in children is not well described yet.

AIMS

In the present study, we aimed to describe the relationship between thiopurine metabolite levels, infliximab trough levels, anti-IFX antibody formation, and clinical and laboratory markers of disease activity in pediatric patients with Crohn's disease, and to assess non-adherence.

METHODS

Data were collected prospectively during repeated visits from pediatric patients followed for Crohn's disease in two Czech pediatric inflammatory bowel disease centers between January 2016 and June 2017. Thiopurine metabolites (6-thioguanine and 6-methylmercaptopurine) were measured by high-performance liquid chromatography. Infliximab trough levels and anti-IFX antibody serum levels were measured routinely by ELISA. The risk of loss of response to infliximab therapy was also assessed.

RESULTS

A significant association between infliximab serum levels and 6-thioguanine erythrocyte levels was observed when tested as categorical variables (63 patients, 321 observations). To predict infliximab levels > 5 µg/mL, we propose a 6-thioguanine cutoff of 278 pmol/8 × 10⁸ erythrocytes (sensitivity, 0.799; specificity, 0.347). A higher loss-of-response-to-infliximab rate (tested in a subgroup of 51 patients) was observed in patients with undetectable 6-thioguanine levels than in those with detectable levels (p = 0.026). Non-adherence to azathioprine therapy was suspected in 20% of patients.

CONCLUSION

Thiopurine metabolite monitoring in pediatric patients with Crohn's disease is useful when optimizing combination therapy. Pediatric patients with undetectable 6-thioguanine levels are more likely to lose response to infliximab therapy. When targeting optimal infliximab levels, the 6-thioguanine cutoff levels in children appear to be higher than in adults.

Real-World Infliximab Pharmacokinetic Study Informs an Electronic Health Record-Embedded Dashboard to Guide Precision Dosing in Children with Crohn's Disease

Standard-of-care infliximab dosing regimens were developed prior to the routine use of therapeutic drug monitoring and identification of target concentrations. Not surprisingly, subtherapeutic infliximab concentrations in pediatric Crohn's disease (CD) are common. The primary aim was to conduct a real-world pharmacokinetic (PK) evaluation to discover blood biomarkers of rapid clearance, identify exposure targets, and a secondary aim to translate PK modeling to the clinic. In a multicenter observational study, 671 peak and trough infliximab concentrations from 78 patients with CD were analyzed with a drug-tolerant assay (Esoterix; LabCorp, Calabasas, CA). Individual area under the curve (AUC) estimates were generated as a measure of drug exposure over time. Population PK modeling (nonlinear mixed-effect modeling) identified serum albumin, antibody to infliximab, erythrocyte sedimentation rate (ESR), and neutrophil CD64 as biomarkers for drug clearance. Week 14 and week 52 biochemical remitters (fecal calprotectin < 250 µg/g) had higher infliximab exposure (AUC) throughout induction. The optimal infliximab AUC target during induction for week 14 biochemical remission was 79,348 µg*h/mL (area under the receiver operating characteristic curve (AUROC) 0.77, [0.63-0.90], 85.7% sensitive, and 64.3% specific) with those exceeding the AUC target more likely to achieve a surgery-free week 52 biochemical remission (OR 4.3, [1.2-14.6]). Pretreatment predictors for subtherapeutic week 14 AUC included neutrophil CD64 > 6 (OR 4.5, [1.4-17.8]), ESR > 30 mm/h (OR 3.8, [1.4-11]), age < 10 years old (OR 4.2, [1.2-20]), and weight < 30 kg (OR 6.6, [2.1-25]). We created a decision-support PK dashboard with an iterative process and embedded the modeling program within the electronic health record. Model-informed precision dosing guided by real-world PKs is now available at the bedside in real-time.

Combination Immunotherapy Use and Withdrawal in Pediatric Inflammatory Bowel Disease-A Review of the Evidence

Evidence-based guidelines have been developed outlining the concomitant use of anti-tumor necrosis factor alpha (anti-TNF) agents and immunomodulators including azathioprine (AZA) and methotrexate (MTX) in both adult and pediatric populations. However, there exists a paucity of data guiding evidence-based strategies for their withdrawal in pediatric patients in sustained remission. This narrative review focuses on the available pediatric evidence on this question in the context of what is known from the larger body of evidence available from adult studies. The objective is to provide clarity and practical guidance around who, what, when, and how to step down pediatric patients with inflammatory bowel disease (IBD) from combination immunotherapy. Outcomes following withdrawal of either of the two most commonly used anti-TNF therapies [infliximab (IFX) or adalimumab (ADA)], or immunomodulator therapies, from a combination regimen are examined. Essentially, a judicious approach must be taken to identify a significant minority of patients who would benefit from treatment rationalization. We conclude that step-down to anti-TNF (rather than immunomodulator) monotherapy after at least 6 months of sustained clinical remission is a viable option for a select group of pediatric patients. This group includes those with good indicators of mucosal healing, low or undetectable anti-TNF trough levels, lack of predictors for severe disease, and no prior escalation of anti-TNF therapy. Transmural healing and specific human leukocyte antigen (HLA) typing are some of the emerging targets and tools that may help facilitate improved outcomes in this process. We also propose a simplified evidence-based schema that may assist in this decision-making process. Further pediatric clinical studies are required to develop the evidence base for decision-making in this area.

Discontinuation of Immunosuppressive Medications in Children With Inflammatory Bowel Disease on Combination Therapy

We determined the frequency and factors associated with the first clinical relapse after immunomodulator (IM) withdrawal in a cohort of children with inflammatory bowel disease on combination therapy. A total of 105 patients (89 with Crohn disease [CD]) in clinical remission were included (91 [86.7%] were on infliximab, 53 [50.5%] with methotrexate, and 52 on azathioprine). The median duration of combination therapy was 2.1 years (interquartile range [IQR] 1.3-2.8). Only 11 (10.5%) patients experienced a clinical relapse over a median duration of follow-up of 12.0 months (IQR 5.0-19.0) after IM discontinuation. The median baseline pediatric CD activity index in those with CD who relapsed after IM discontinuation was 47.5 (IQR: 35.0-55.0) versus those who did not relapse (median 35.0, IQR: 20.0-52.5; P = 0.04). In the patients who did not relapse, the median IFX trough level at IM discontinuation was 6.2 and 3.8 μg/mL in those who relapsed.

First United Arab Emirates consensus on diagnosis and management of inflammatory bowel diseases: A 2020 Delphi consensus

Ulcerative colitis and Crohn’s disease are the main entities of inflammatory bowel disease characterized by chronic remittent inflammation of the gastrointestinal tract. The incidence and prevalence are on the rise worldwide, and the heterogeneity between patients and within individuals over time is striking. The progressive advance in our understanding of the etiopathogenesis coupled with an unprecedented increase in therapeutic options have changed the management towards evidence-based interventions by clinicians with patients. This guideline was stimulated and supported by the Emirates Gastroenterology and Hepatology Society following a systematic review and a Delphi consensus process that provided evidence- and expert opinion-based recommendations. Comprehensive up-to-date guidance is provided regarding diagnosis, evaluation of disease severity, appropriate and timely use of different investigations, choice of appropriate therapy for induction and remission phase according to disease severity, and management of main complications.

Multiomic features associated with mucosal healing and inflammation in paediatric Crohn's disease

BACKGROUND

The gastrointestinal microbiota has an important role in mucosal immune homoeostasis and may contribute to maintaining mucosal healing in Crohn's disease (CD).

AIM

To identify changes in the microbiota, metabolome and protease activity associated with mucosal healing in established paediatric CD METHODS: Twenty-five participants aged 3-18 years with CD, disease duration of over 6 months, and maintenance treatment with biological therapy were recruited. They were divided into a low calprotectin group (faecal calprotectin <100 μg/g, "mucosal healing," n = 11), and a high calprotectin group (faecal calprotectin >100 μg/g, "mucosal inflammation," n = 11). 16S gene-based metataxonomics, ¹ H-NMR spectroscopy-based metabolic profiling and protease activity assays were performed on stool samples.

RESULTS

Relative abundance of Dialister species was six-times greater in the low calprotectin group (q = 0.00999). Alpha and beta diversity, total protease activity and inferred metagenomic profiles did not differ between groups. Pentanoate (valerate) and lysine were principal discriminators in a machine-learning model which differentiated high and low calprotectin samples using NMR spectra (R² 0.87, Q² 0.41). Mean relative concentration of pentanoate was 1.35-times greater in the low calprotectin group (95% CI 1.03-1.68, P = 0.036) and was positively correlated with Dialister. Mean relative concentration of lysine was 1.54-times greater in the high calprotectin group (95% CI 1.05-2.03, P = 0.028).

CONCLUSIONS

This multiomic study identified an increase in Dialister species and pentanoate, and a decrease in lysine, in patients with "mucosal healing." It supports further investigation of these as potential novel therapeutic targets in CD.

Combination Therapy of Adalimumab With an Immunomodulator Is Not More Effective Than Adalimumab Monotherapy in Children With Crohn's Disease: A Post Hoc Analysis of the PAILOT Randomized Controlled Trial

BACKGROUND

The PAILOT trial was a randomized controlled trial aimed to evaluate proactive vs reactive therapeutic drug monitoring in children with Crohn's disease (CD) treated with adalimumab. Our aim in this post hoc analysis of the PAILOT trial was to assess the efficacy and safety of adalimumab combination treatment in comparison with monotherapy at week 72 after adalimumab induction.

METHODS

Participants were children 6-17 years old, biologic naïve, with moderate to severe CD, who responded to adalimumab induction at week 4. Patients receiving immunomodulators at baseline maintained a stable dose until week 24; patients could then discontinue immunomodulators. At each visit, patients were assessed for disease index, serum biomarkers, fecal calprotectin, adalimumab trough concentration, and anti-adalimumab antibodies.

RESULTS

Out of the 78 patients (29% female; mean age, 14.3 ± 2.6 years), 34 patients (44%) received combination therapy. During the study period, there was no significant difference in the rates of sustained corticosteroid-free clinical remission (25/34, 73%, vs 28/44, 63%; P = 0.35) or sustained composite outcome of clinical remission, C-reactive protein ≤0.5 mg/dL, and calprotectin ≤150 µg/g (10/34, 29%, vs 14/44, 32%; P = 0.77) between the combination group and the monotherapy group, respectively. Clinical and biological outcomes did not differ between the proactive and reactive subgroups within the combination and monotherapy groups. Adalimumab trough concentrations and immunogenicity were not significantly different between groups. The rate of serious adverse events was not significantly different between groups but was numerically higher in the monotherapy group.

CONCLUSIONS

Combination therapy of adalimumab and an immunomodulator was not more effective than adalimumab monotherapy in children with CD (ClinicalTrials.gov No. NCT02256462).

The Medical Management of Paediatric Crohn's Disease: an ECCO-ESPGHAN Guideline Update

OBJECTIVE

We aimed to provide an evidence-supported update of the ECCO-ESPGHAN guideline on the medical management of paediatric Crohn's disease [CD].

METHODS

We formed 10 working groups and formulated 17 PICO-structured clinical questions [Patients, Intervention, Comparator, and Outcome]. A systematic literature search from January 1, 1991 to March 19, 2019 was conducted by a medical librarian using MEDLINE, EMBASE, and Cochrane Central databases. A shortlist of 30 provisional statements were further refined during a consensus meeting in Barcelona in October 2019 and subjected to a vote. In total 22 statements reached ≥ 80% agreement and were retained.

RESULTS

We established that it was key to identify patients at high risk of a complicated disease course at the earliest opportunity, to reduce bowel damage. Patients with perianal disease, stricturing or penetrating behaviour, or severe growth retardation should be considered for up-front anti-tumour necrosis factor [TNF] agents in combination with an immunomodulator. Therapeutic drug monitoring to guide treatment changes is recommended over empirically escalating anti-TNF dose or switching therapies. Patients with low-risk luminal CD should be induced with exclusive enteral nutrition [EEN], or with corticosteroids when EEN is not an option, and require immunomodulator-based maintenance therapy. Favourable outcomes rely on close monitoring of treatment response, with timely adjustments in therapy when treatment targets are not met. Serial faecal calprotectin measurements or small bowel imaging [ultrasound or magnetic resonance enterography] are more reliable markers of treatment response than clinical scores alone.

CONCLUSIONS

We present state-of-the-art guidance on the medical treatment and long-term management of children and adolescents with CD.

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.

Effect of a Practice-wide Anti-TNF Proactive Therapeutic Drug Monitoring Program on Outcomes in Pediatric Patients with Inflammatory Bowel Disease

BACKGROUND

Reports on the feasibility and effectiveness of translating proactive, antitumor necrosis factor (TNF) therapeutic drug monitoring (TDM) for inflammatory bowel disease into practice-wide quality improvement (QI) are lacking. We aimed to determine whether a TDM QI program improved outcomes at a large academic pediatric gastroenterology practice.

METHODS

We instituted local anti-TNF TDM practice guidelines to proactively monitor and optimize drug levels (goal >5 μg/mL). We conducted a retrospective single-center cohort analysis of patient outcomes before (pre-TDM) and after (post-TDM) guideline institution and assessed the independent effect by multivariable regression. Primary outcome was sustained clinical remission (SCR22-52), defined as physician global assessment (PGA) of inactive from 22 to 52 weeks and off corticosteroids at 52 weeks.

RESULTS

We identified 108 pre-TDM and 206 post-TDM patients. The SCR22-52 was achieved in 42% of pre-TDM and 59% of post-TDM patients (risk difference, 17.6%; 95% CI, 5.4-29%; P = 0.004). The post-TDM group had an increased adjusted odds of achieving SCR22-52 (odds ratio, 2.03; 95% CI, 1.27-3.26; P = 0.003). The adjusted risk of developing high titer antidrug antibodies (ADAs) was lower in the post-TDM group (hazard ratio, 0.18; 95% CI, 0.09-0.35; P < 0.001). Although the risk of anti-TNF cessation for any reason was not significantly different, there was a lower adjusted risk of cessation related to any detectable ADA in the post-TDM group (hazard ratio, 0.45; 95% CI, 0.26-0.77; P = 0.003).

CONCLUSIONS

A practice-wide proactive anti-TNF TDM QI program improved key clinical outcomes at our institution, including sustained clinical remission, incidence of high titer ADA, and anti-TNF cessation related to ADA.

Favorable Outcomes and Anti-TNF Durability After Addition of an Immunomodulator for Anti-Drug Antibodies in Pediatric IBD Patients

BACKGROUND

Anti-drug antibodies (ADAs) to anti-tumor necrosis factor alpha (anti-TNF) drugs are associated with increased drug clearance and loss of response. We aimed to assess the effectiveness of starting an immunomodulator (IM) drug in patients with newly detected ADAs on anti-TNF monotherapy.

METHODS

We reviewed the medical records of pediatric patients with inflammatory bowel disease on infliximab or adalimumab monotherapy with first-time detection of significant ADAs between 2014 and 2018. Patients who started an IM within 3 months of ADA detection were compared with those who did not (No-IM). Outcomes included steroid-free clinical and biochemical remission on the same anti-TNF , anti-TNF durability, and ADA reversal.

RESULTS

We identified 89 patients with ADAs: 30 IM patients and 59 No-IM patients. The initial anti-TNF was stopped shortly after ADA detection in 36% of the No-IM patients vs none of the IM patients, driving longer survival on the initial anti-TNF in the IM group (P = 0.005). At 12 months, steroid-free clinical and biochemical remission on the same anti-TNF occurred in 53.9% of the IM group vs 26.8% in the No-IM group (P = 0.025). Drug levels rose higher (P = 0.003) and ADA levels fell farther (P = 0.037) in the IM group than in the No-IM group. Baseline ADA level predicted ADA reversal in the No-IM patients with an area under the receiver operating characteristic of 0.79 (P = 0.006). An ADA level <329 ng/mL had a 76.2% sensitivity and an 83.3% specificity for ADA reversal without IM.

CONCLUSIONS

Pediatric patients with inflammatory bowel disease on anti-TNF monotherapy who started an IM for significant ADA levels exhibited longer anti-TNF durability and a higher likelihood of steroid-free clinical and biochemical remission on the same anti-TNF. Patients not treated with an IM were unlikely to reverse ADAs >329 ng/mL.

Augmented ustekinumab dosing is needed to achieve clinical response in patients with anti-TNF refractory pediatric Crohn's disease: a retrospective chart review

Background: Ustekinumab is a monoclonal antibody that inhibits interleukins 12 and 23. It is approved for treatment of Crohn's disease (CD) in adults; however, there is a paucity of data regarding its use in pediatric CD. We describe our experience using ustekinumab in anti-TNF refractory CD pediatric patients. Methods: We performed a retrospective chart review on pediatric patients with CD who were started on ustekinumab from January 2016 to November 2018. We collected patient's clinical history, previous treatment history, surgeries related to CD, disease severity, as measured by abbrPCDAI, and endoscopic severity as recorded by SES-CD before and after ustekinumab. Results: We identified 10 patients with CD who were started on ustekinumab due to non-response to currently approved agents. Seven patients needed augmented maintenance dosing every 4-6 weeks to achieve clinical response or remission. Six of these seven patients had therapeutic drug monitoring during the course of treatment, with five patients showing subtherapeutic drug levels of <4.5 μg/mL while on standard maintenance dosing every 8 weeks, and four patients showing therapeutic drug levels of >4.5 μg/mL on augmented dosing interval. The remaining three patients were on standard maintenance dosing for the duration of treatment. Conclusion: In this retrospective chart review, 7 out of 10 patients with anti-TNF refractory pediatric-onset CD required augmented maintenance doses of ustekinumab to achieve clinical response or remission. A prospective study is needed to define appropriate ustekinumab dosing and interval in management of pediatric CD.

Augmented ustekinumab dosing is needed to achieve clinical response in patients with anti-TNF refractory pediatric Crohn's disease: a retrospective chart review

Background: Ustekinumab is a monoclonal antibody that inhibits interleukins 12 and 23. It is approved for treatment of Crohn's disease (CD) in adults; however, there is a paucity of data regarding its use in pediatric CD. We describe our experience using ustekinumab in anti-TNF refractory CD pediatric patients. Methods: We performed a retrospective chart review on pediatric patients with CD who were started on ustekinumab from January 2016 to November 2018. We collected patient's clinical history, previous treatment history, surgeries related to CD, disease severity, as measured by abbrPCDAI, and endoscopic severity as recorded by SES-CD before and after ustekinumab. Results: We identified 10 patients with CD who were started on ustekinumab due to non-response to currently approved agents. Seven patients needed augmented maintenance dosing every 4-6 weeks to achieve clinical response or remission. Six of these seven patients had therapeutic drug monitoring during the course of treatment, with five patients showing subtherapeutic drug levels of <4.5 μg/mL while on standard maintenance dosing every 8 weeks, and four patients showing therapeutic drug levels of >4.5 μg/mL on augmented dosing interval. The remaining three patients were on standard maintenance dosing for the duration of treatment. Conclusion: In this retrospective chart review, 7 out of 10 patients with anti-TNF refractory pediatric-onset CD required augmented maintenance doses of ustekinumab to achieve clinical response or remission. A prospective study is needed to define appropriate ustekinumab dosing and interval in management of pediatric CD.

Long-Term Efficacy of Anti-Tumor Necrosis Factor Agents in Pediatric Luminal Crohn's Disease: A Systematic Review of Real-World Evidence Studies

PURPOSE

To determine the long-term efficacy of the anti-tumor necrosis factor (TNF) agents, infliximab (IFX) and adalimumab (ADA), in pediatric luminal Crohn's disease (CD) by performing a systematic literature review.

METHODS

An electronic search was performed in Medline, Embase, and the Cochrane Library from inception to September 26, 2019. Eligible studies were cohort studies with observation periods that exceeded 1 year. Studies that reported time-to-event analyses were included. Events were defined as discontinuation of anti-TNF therapy for secondary loss of response. We extracted the probabilities of continuing anti-TNF therapy 1, 2, and 3 years after initiation.

RESULTS

In total, 2,464 papers were screened, 94 were selected for full text review, and 13 studies (11 on IFX, 2 on ADA) met our eligibility criteria for inclusion. After 1 year, 83-97% of patients were still receiving IFX therapy. After 2 and 3 years the probability of continuing IFX therapy decreased to 67-91% and 61-85%, respectively. In total, 5 of the 11 studies subgrouped by concomitant medication consistently showed that the probabilities of continuing IFX therapy in patients with prolonged immunomodulator use were higher than those in patients on IFX monotherapy.

CONCLUSION

This review of real-world evidence studies confirms the long-term therapeutic benefit of IFX therapy in diverse cohorts of children with luminal CD. Moreover, it supports the view that combination therapy with an immunomodulator prolongs the durability of IFX therapy in patients who previously failed to recover following first-line therapy. The limited number of time-to-event studies in patients on ADA prevented us from drawing definite conclusions about its long-term efficacy.

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.

Recent advances in understanding and managing pediatric inflammatory bowel disease

The landscape of pediatric inflammatory bowel disease is rapidly evolving. The therapeutic advances seen in the adult arena are rapidly being adopted by pediatric gastroenterologists and evaluated in both controlled trials and real-world experience. Though anti-tumor necrosis factor agents have been the primary therapy over the last decade, recently there has been an expansion of therapeutic targets and alternative mechanism of action drugs with a focus on individualized and personalized therapy. By reviewing epidemiology, pathophysiology, and goals of treatment, we hope to frame the discussion of current and novel therapeutics for the pediatric gastroenterologist. As scientific discovery continues to push the envelope in defining our understanding of pediatric inflammatory bowel disease, the current era of therapeutics gives us hope that a cure may be realized soon.

British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults

Ulcerative colitis and Crohn's disease are the principal forms of inflammatory bowel disease. Both represent chronic inflammation of the gastrointestinal tract, which displays heterogeneity in inflammatory and symptomatic burden between patients and within individuals over time. Optimal management relies on understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This guideline for management of inflammatory bowel disease in adults over 16 years of age was developed by Stakeholders representing UK physicians (British Society of Gastroenterology), surgeons (Association of Coloproctology of Great Britain and Ireland), specialist nurses (Royal College of Nursing), paediatricians (British Society of Paediatric Gastroenterology, Hepatology and Nutrition), dietitians (British Dietetic Association), radiologists (British Society of Gastrointestinal and Abdominal Radiology), general practitioners (Primary Care Society for Gastroenterology) and patients (Crohn's and Colitis UK). A systematic review of 88 247 publications and a Delphi consensus process involving 81 multidisciplinary clinicians and patients was undertaken to develop 168 evidence- and expert opinion-based recommendations for pharmacological, non-pharmacological and surgical interventions, as well as optimal service delivery in the management of both ulcerative colitis and Crohn's disease. Comprehensive up-to-date guidance is provided regarding indications for, initiation and monitoring of immunosuppressive therapies, nutrition interventions, pre-, peri- and postoperative management, as well as structure and function of the multidisciplinary team and integration between primary and secondary care. Twenty research priorities to inform future clinical management are presented, alongside objective measurement of priority importance, determined by 2379 electronic survey responses from individuals living with ulcerative colitis and Crohn's disease, including patients, their families and friends.

British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults

Ulcerative colitis and Crohn's disease are the principal forms of inflammatory bowel disease. Both represent chronic inflammation of the gastrointestinal tract, which displays heterogeneity in inflammatory and symptomatic burden between patients and within individuals over time. Optimal management relies on understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This guideline for management of inflammatory bowel disease in adults over 16 years of age was developed by Stakeholders representing UK physicians (British Society of Gastroenterology), surgeons (Association of Coloproctology of Great Britain and Ireland), specialist nurses (Royal College of Nursing), paediatricians (British Society of Paediatric Gastroenterology, Hepatology and Nutrition), dietitians (British Dietetic Association), radiologists (British Society of Gastrointestinal and Abdominal Radiology), general practitioners (Primary Care Society for Gastroenterology) and patients (Crohn's and Colitis UK). A systematic review of 88 247 publications and a Delphi consensus process involving 81 multidisciplinary clinicians and patients was undertaken to develop 168 evidence- and expert opinion-based recommendations for pharmacological, non-pharmacological and surgical interventions, as well as optimal service delivery in the management of both ulcerative colitis and Crohn's disease. Comprehensive up-to-date guidance is provided regarding indications for, initiation and monitoring of immunosuppressive therapies, nutrition interventions, pre-, peri- and postoperative management, as well as structure and function of the multidisciplinary team and integration between primary and secondary care. Twenty research priorities to inform future clinical management are presented, alongside objective measurement of priority importance, determined by 2379 electronic survey responses from individuals living with ulcerative colitis and Crohn's disease, including patients, their families and friends.

The pharmacotherapeutic management of pediatric Crohn's disease

Introduction: Crohn's disease (CD) is a chronic inflammatory condition that can occur throughout the gastrointestinal tract. The aims of treatment of children with CD are to induce and maintain clinical remission of disease, optimize nutrition and growth, minimize adverse effects of therapies, and if possible, achieve mucosal healing.Areas covered: This review summarizes evidence for the various therapeutic options in the treatment of children with CD. Exclusive enteral nutrition, corticosteroids, and biologics may be used for induction of remission. Immunomodulators (thiopurines, methotrexate) and biologics (infliximab, adalimumab) may be employed for maintenance of remission to prevent flares of disease and avoid chronic steroid use. In cases of fibrotic disease, intestinal perforations, or medically refractory, surgery may be the best therapeutic option.Expert opinion: Exclusive enteral nutrition, corticosteroids, and biologics (including anti-TNF inhibitors) may be used for induction of remission in patients with active flare of their disease. Immunomodulators and TNF inhibitors may be used for maintenance of remission. Early use of anti-TNF inhibitors in patients with moderate to severe CD may improve efficacy and prevent penetrating complications of disease. While pediatric data is limited, newer biologics, such as vedolizumab and ustekinumab, are used off-label in anti-TNF refractory disease.

Prediction of Thiopurine Metabolite Levels Based on Haematological and Biochemical Parameters

OBJECTIVES

Therapeutic drug monitoring of thiopurine erythrocyte levels is not available in all centers and it usually requires quite a long time to obtain the results. The aims of this study were to build a model predicting low levels of 6-thioguanine and 6-methylmercaptopurine in pediatric inflammatory bowel disease (IBD) patients and to build a model to predict nonadherence in patients treated with azathioprine (AZA).

METHODS

The study consisted of 332 observations in 88 pediatric IBD patients. Low AZA dosing was defined as 6-thioguanine levels <125 pmol/8 × 10 erythrocytes and 6-methylmercaptopurine levels <5700 pmol/8 × 10 erythrocytes. Nonadherence was defined as undetectable levels of 6-thioguanine and 6-methylmercaptopurine <240 pmol/8 × 10 erythrocytes. Data were divided into training and testing part. To construct the model predicting low 6-thioguanine levels, nonadherence, and the level of 6-thioguanine, the modification of random forest method with cross-validation and resampling was used.

RESULTS

The final models predicting low 6-thioguanine levels and nonadherence had area under the curve, 0.87 and 0.94; sensitivity, 0.81 and 0.82; specificity, 0.80 and 86; and distance, 0.31 and 0.21, respectively, when applied on the testing part of the dataset. When the final model for prediction of 6-thioguanine values was applied on testing dataset, a root-mean-square error of 110 was obtained.

CONCLUSIONS

Using easily obtained laboratory parameters, we constructed a model with sufficient accuracy to predict patients with low 6-thioguanine levels and a model for prediction of AZA treatment nonadherence (web applications: https://hradskyo.shinyapps.io/6TG_prediction/ and https://hradskyo.shinyapps.io/Non_adherence/).

Canadian Association of Gastroenterology Clinical Practice Guideline for the Medical Management of Pediatric Luminal Crohn's Disease

BACKGROUND & AIMS

We aim to provide guidance for medical treatment of luminal Crohn's disease in children.

METHODS

We performed a systematic search of publication databases to identify studies of medical management of pediatric Crohn's disease. Quality of evidence and strength of recommendations were rated according to the GRADE (Grading of Recommendation Assessment, Development, and Evaluation) approach. We developed statements through an iterative online platform and then finalized and voted on them.

RESULTS

The consensus includes 25 statements focused on medical treatment options. Consensus was not reached, and no recommendations were made, for 14 additional statements, largely due to lack of evidence. The group suggested corticosteroid therapies (including budesonide for mild to moderate disease). The group suggested exclusive enteral nutrition for induction therapy and biologic tumor necrosis factor antagonists for induction and maintenance therapy at diagnosis or at early stages of severe disease, and for patients failed by steroid and immunosuppressant induction therapies. The group recommended against the use of oral 5-aminosalicylate for induction or maintenance therapy in patients with moderate disease, and recommended against thiopurines for induction therapy, corticosteroids for maintenance therapy, and cannabis in any role. The group was unable to clearly define the role of concomitant immunosuppressants during initiation therapy with a biologic agent, although thiopurine combinations are not recommended for male patients. No consensus was reached on the role of aminosalicylates in treatment of patients with mild disease, antibiotics or vedolizumab for induction or maintenance therapy, or methotrexate for induction therapy. Patients in clinical remission who are receiving immunomodulators should be assessed for mucosal healing within 1 year of treatment initiation.

CONCLUSIONS

Evidence-based medical treatment of Crohn's disease in children is recommended, with thorough ongoing assessments to define treatment success.

Canadian Association of Gastroenterology Clinical Practice Guideline for the Medical Management of Pediatric Luminal Crohn's Disease

BACKGROUND & AIMS

We aim to provide guidance for medical treatment of luminal Crohn's disease in children.

METHODS

We performed a systematic search of publication databases to identify studies of medical management of pediatric Crohn's disease. Quality of evidence and strength of recommendations were rated according to the GRADE (Grading of Recommendation Assessment, Development, and Evaluation) approach. We developed statements through an iterative online platform and then finalized and voted on them.

RESULTS

The consensus includes 25 statements focused on medical treatment options. Consensus was not reached, and no recommendations were made, for 14 additional statements, largely due to lack of evidence. The group suggested corticosteroid therapies (including budesonide for mild to moderate disease). The group suggested exclusive enteral nutrition for induction therapy and biologic tumor necrosis factor antagonists for induction and maintenance therapy at diagnosis or at early stages of severe disease, and for patients failed by steroid and immunosuppressant induction therapies. The group recommended against the use of oral 5-aminosalicylate for induction or maintenance therapy in patients with moderate disease, and recommended against thiopurines for induction therapy, corticosteroids for maintenance therapy, and cannabis in any role. The group was unable to clearly define the role of concomitant immunosuppressants during initiation therapy with a biologic agent, although thiopurine combinations are not recommended for male patients. No consensus was reached on the role of aminosalicylates in treatment of patients with mild disease, antibiotics or vedolizumab for induction or maintenance therapy, or methotrexate for induction therapy. Patients in clinical remission who are receiving immunomodulators should be assessed for mucosal healing within 1 year of treatment initiation.

CONCLUSIONS

Evidence-based medical treatment of Crohn's disease in children is recommended, with thorough ongoing assessments to define treatment success.

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

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

Characteristics of biological therapy in pediatric patients with Crohn's disease

INTRODUCTION

At present, there is a significant amount of data related to biologics used in pediatric patients with Crohn's disease. This review characterizes the different biological drugs administered in this population.

AREAS COVERED

Biological therapy of CD, focusing on children, is summarized in this review. After mechanism of action and pharmacokinetics are described, mucosal healing on anti-TNF therapy, aspects of early therapy, long-term outcome and combination therapy are discussed. Moreover, loss of response and treatment optimization, as well as drug withdrawal are summarized. Subsequently, perianal disease and surgical aspects are discussed followed by safety issues. In addition, new drugs (vedolizumab, ustekinumab), cost-effectiveness and administration of biosimilars were also included.

EXPERT COMMENTARY

There are significant data to characterize biological drugs administered in pediatric patients with Crohn's disease. However, head-to-head comparative studies using different biologics are missing.

The effects of concomitant immunomodulators on the pharmacokinetics, efficacy and safety of adalimumab in paediatric patients with Crohn's disease: a post hoc analysis

BACKGROUND

In the IMAgINE 1 study, adalimumab induced and maintained remission of moderate-to-severe Crohn's disease in children.

AIM

To assess the efficacy, pharmacokinetics, immunogenicity and safety of immunomodulator and adalimumab combination therapy vs adalimumab monotherapy in paediatric patients with Crohn's disease.

METHODS

Patients 6-17 years old with moderate-to-severe Crohn's disease (n = 192) received weight-based adalimumab induction at baseline and week 2. At week 4, 188 patients were randomised to high-dose or low-dose adalimumab. Patients receiving immunomodulators (investigator's decision) at baseline maintained a stable dose until week 26; patients could then discontinue immunomodulators. Adalimumab serum concentrations were measured at weeks 4, 26 and 52. Safety was evaluated at each study visit. Data were analysed using non-responder imputation (NRI; week 4) or modified NRI (weeks 26; 52).

RESULTS

At week 4, patients with (n = 117) and without (n = 71) baseline immunomodulator use had similar response (79%; 87%; P = 0.235) and remission (26%; 30%; P = 0.737) rates. At week 26, patients with and without baseline immunomodulators had no significant difference in response (68%; 55%; P = 0.086) or remission (41%; 30%; P = 0.122). At week 52, patients with (n = 82) and without (n = 106) immunomodulator use had no significant difference in response (56%; 46%; P = 0.189) or remission (38%; 33%; P = 0.539). Adalimumab serum trough concentrations and serious infection rates (7%; 6%) were not significantly different between groups.

CONCLUSIONS

Analyses found no statistically significant difference in response or remission between patients receiving adalimumab monotherapy vs immunomodulator and adalimumab combination therapy. Serious and infectious adverse event rates were similar between groups.

Higher Infliximab Trough Levels Are Associated With Better Outcome in Paediatric Patients With Inflammatory Bowel Disease

BACKGROUND

The role of therapeutic drug monitoring for infliximab [IFX] therapy in children with inflammatory bowel disease [IBD] is poorly investigated. We determined if IFX exposure correlates with long-term remission in children.

METHODS

In this retrospective study, all children with Crohn's disease [CD] and ulcerative colitis [UC], receiving maintenance IFX at our centre, were included. Serum trough levels and cumulative drug exposure were correlated with clinical, biological, and endoscopic remission. All children received proactive drug monitoring and dose adaptation aiming to target a therapeutic window of 3-7 µg/mL. All data are presented as median [interquartile range].

RESULTS

A total of 686 serum levels during IFX maintenance in 52 paediatric patients [33 CD and 19 UC] were included (median 9 [4-18] per patient). With a median of 17 [8-36] months under IFX therapy, 39/52 [75%] patients were in clinical remission and 29/40 [73%] patients were in endoscopic remission. Median IFX trough levels were significantly higher when children achieved clinical remission (5.4 [3.8-8.0] µg/mL versus 4.2 [2.6-6.7] µg/mL), biological remission (5.2 [3.7-7.7] µg/mL versus 4.2 [2.6-6.5] µg/mL), combined clinical and biological remission (5.7 [4.0-8.2] µg/mL versus 4.4 [2.7-6.8] µg/mL) and endoscopic remission (6.5 [4.2-9.5] µg/mL versus 3.2 [2.3-5.6] µg/mL) compared with not meeting these criteria [all p ≤ 0.001].

CONCLUSIONS

In this large paediatric cohort, children with clinical and/or endoscopic remission had significantly higher IFX exposure during maintenance therapy. We showed excellent outcome data using serial and systematic measurements of drug levels. This could provide a rationale for the use of proactive drug monitoring in children in order to improve long-term outcomes.

Update on the Use of Thiopurines and Methotrexate in Inflammatory Bowel Disease

PURPOSE OF REVIEW

The increased use of biologic agents over the past two decades has led to a reappraisal of the role of the immunomodulators (thiopurines and methotrexate) in the treatment of inflammatory bowel disease. The purpose of this review is to summarize recent data on the use of thiopurines and methotrexate either as monotherapy or as part of combination therapy with biologic agents.

RECENT FINDINGS

Recent studies have addressed the need for concomitant immunomodulatory therapy in treatment-naïve patients starting anti-TNF-α therapy, the appropriate dose of the immunomodulator in this setting, the minimum duration of combination therapy, and the possible mechanisms by which immunomodulators enhance the effectiveness of anti-TNF-α agents. Little is known about the role of immunomodulators in combination with agents belonging to other classes of biologic therapies. Recent studies have shown that methotrexate is not effective in inducing or maintaining remission in ulcerative colitis. Finally, several studies have broadened our understanding of the infection and malignancy risks of the immunomodulators. Immunomodulators continue to have a place in the treatment of inflammatory bowel disease. However, with the ever-increasing list of biologic agents, properly positioning the immunomodulators within the overall therapeutic scheme is a complicated task. In order to optimize outcomes, each patient requires an individualized approach, which takes into account risks, benefits, cost, alternatives, and patient preferences.

Therapeutic role of methotrexate in pediatric Crohn's disease

The main role of therapy in Crohn's disease (CD) is to achieve long-term clinical remission, and to allow for normal growth and development of children. The immunomodulatory drugs used for the maintenance of remission in CD include thiopurines (azathioprine and 6-mercaptopurine) and methotrexate (MTX). Development of hepatosplenic T-cell lymphoma in some patients with inflammatory bowel disease, treated with thiopurines only or in combination with anti-tumor necrosis factor agents, resulted in a growing interest in the therapeutic application of MTX in children suffering from CD. This review summarizes the literature on the therapeutic role of MTX in children with CD. MTX is often administered as a second-line immunomodulator, and 1-year clinical remission was reported in 25-69% of children with CD after excluding for the use of thiopurines. Initial data on MTX effectiveness in mucosal healing, and as a first-line immunomodulator in pediatric patients with CD, are promising. A definite conclusion, however, may only be made on the basis of additional research with a larger number of subjects.

The Continental Divide: Anti-TNF Use in Pediatric IBD Is Different in North America Compared to Other Parts of the World

BACKGROUND AND AIMS

Use of anti-TNF therapies varies internationally. As an initiative of the international Pediatric IBD Network (PIBDNet), we compared global pediatric IBD anti-TNF practice patterns.

METHODS

Physicians were surveyed about anti-TNF use in Crohn's disease (CD) and ulcerative colitis (UC). Chi-squared, independent samples Mann-Whitney U, or related samples Wilcoxon signed rank tests were used to compare groups.

RESULTS

344 physicians treating pediatric IBD responded from 43 countries (54% North America, 29% Europe, 6% Oceania, 6% Asia, 3% Africa, and 2% South America). Respondents treated a median 40 IBD patients. CD was more commonly treated with anti-TNF than UC (40% vs. 10%, p<0.001). North Americans more often used anti-TNF (median 50% vs. 30%, p<0.001) and before immunomodulator (80% vs. 35% CD, p<0.001; 76% vs. 43% steroid-dependent UC, p<0.001). Anti-TNF monotherapy was more common in North America. Anti-TNF in combination with methotrexate, instead of thiopurine, characterized North American practices. North Americans more often continued immunomodulator indefinitely and less often adhered to standard infliximab induction dosing. Access limitations were more common outside North America and Europe for both CD (67% vs. 31%, p<0.001) and UC (62% vs. 33%, p<0.001).

CONCLUSIONS

Anti-TNF use in North America varies significantly from elsewhere.

Withdrawal of immunosuppressant or biologic therapy for patients with quiescent Crohn's disease

BACKGROUND

Crohn's disease (CD) is a chronic, relapsing and remitting disease of the gastrointestinal tract that can cause significant morbidity and disability. Current treatment guidelines recommend early intervention with immunosuppressant or biological therapy in high-risk patients with a severe disease phenotype at presentation. The feasibility of therapeutic de-escalation once remission is achieved is a commonly encountered question in clinical practice, driven by patient and clinician concerns regarding safety, adverse events, cost and national regulations. Withdrawal of immunosuppressant and biologic drugs in patients with quiescent CD may limit adverse events and reduce healthcare costs. Alternatively, stopping these drug therapies may result in negative outcomes such as disease relapse, drug desensitization, bowel damage and need for surgery.

OBJECTIVES

To assess the feasibility and safety of discontinuing immunosuppressant or biologic drugs, administered alone or in combination, in patients with quiescent CD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and the Cochrane IBD Group Specialized Register from inception to 19 December 2017. We also searched the reference lists of potentially relevant manuscripts and conference proceedings to identify additional studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and prospective cohort studies that followed patients for a minimum duration of six months after drug discontinuation were considered for inclusion. The patient population of interest was adults (> 18 years) with CD (as defined by conventional clinical, endoscopic or histologic criteria) who had achieved remission while receiving immunosuppressant or biologic drugs administered alone or in combination. Patients then discontinued the drug regimen following a period of maintenance therapy of at least six months. The comparison was usual care (i.e. continuation of the drug regimen).

DATA COLLECTION AND ANALYSIS

The primary outcome measure was the proportion of patients who relapsed following discontinuation of immunosuppressant or biologic drugs, administered alone or in combination. Secondary outcomes included: the proportion of patients who responded to the reintroduction of immunosuppressant or biologic drugs, given as monotherapy or combination therapy; the proportion of patients who required surgery following relapse; the proportion of patients who required hospitalization for CD following relapse; the proportion of patients who developed new CD-related complications (e.g. fistula, abscesses, strictures) following relapse; the proportion of patients with elevated biomarkers of inflammation (CRP, fecal calprotectin) in those who stop and those who continue therapy; the proportion of patients with anti-drug antibodies and low serum trough drug levels; time to relapse; and the proportion of patients with adverse events, serious adverse events and withdrawal due to adverse events. For dichotomous outcomes, we calculated the risk ratio (RR) and 95% confidence interval (95% CI). Data were analyzed on an intention-to-treat basis where patients with missing outcome data were assumed to have relapsed. The overall quality of the evidence supporting the primary and secondary outcomes was assessed using the GRADE criteria.

MAIN RESULTS

A total of six RCTs (326 patients) evaluating therapeutic discontinuation in patients with quiescent CD were eligible for inclusion. In four RCTs azathioprine monotherapy was discontinued, and in two RCTs azathioprine was discontinued from a combination therapy regimen consisting of azathioprine with infliximab. No studies of biologic monotherapy withdrawal were eligible for inclusion. The majority of studies received unclear or low risk of bias ratings, with the exception of three open-label RCTs, which were rated as high risk of bias for blinding. Four RCTs (215 participants) compared discontinuation to continuation of azathioprine monotherapy, while two studies (125 participants) compared discontinuation of azathioprine from a combination regimen to continuation of combination therapy. Continuation of azathioprine monotherapy was shown to be superior to withdrawal for risk of clinical relapse. Thirty-two per cent (36/111) of azathioprine withdrawal participants relapsed compared to 14% (14/104) of participants who continued with azathioprine therapy (RR 0.42, 95% CI 0.24 to 0.72, GRADE low quality evidence). However, it is uncertain if there are any between-group differences in new CD-related complications (RR 0.34, 95% CI 0.06 to 2.08, GRADE low quality evidence), adverse events (RR 0.88, 95% CI 0.67 to 1.17, GRADE low quality evidence), serious adverse events (RR 3.29, 95% CI 0.35 to 30.80, GRADE low quality evidence) or withdrawal due to adverse events (RR 2.59, 95% CI 0.35 to 19.04, GRADE low quality evidence). Common adverse events included infections, mild leukopenia, abdominal symptoms, arthralgias, headache and elevated liver enzymes. No differences between azathioprine withdrawal from combination therapy versus continuation of combination therapy were observed for clinical relapse. Among patients who continued combination therapy with azathioprine and infliximab, 48% (27/56) had a clinical relapse compared to 49% (27/55) of patients discontinued azathioprine but remained on infliximab (RR 1.02, 95% CI 0.68 to 1.52, P = 0.32; GRADE low quality evidence). The effects on adverse events (RR 1.11, 95% CI 0.44 to 2.81, GRADE low quality of evidence) or serious adverse events are uncertain (RR 1.00, 95% CI 0.21 to 4.66; GRADE very low quality of evidence). Common adverse events in the combination therapy studies included infections, liver test elevations, arthralgias and infusion reactions.

AUTHORS' CONCLUSIONS

The effects of withdrawal of immunosuppressant therapy in people with quiescent Crohn's disease are uncertain. Low quality evidence suggests that continuing azathioprine monotherapy may be superior to withdrawal for avoiding clinical relapse, while very low quality evidence suggests that there may be no difference in clinical relapse rates between discontinuing azathioprine from a combination therapy regimen, compared to continuing combination therapy. It is unclear whether withdrawal of azathioprine, initially administered alone or in combination, impacts on the development of CD-related complications, adverse events, serious adverse events or withdrawal due to adverse events. Further high-quality research is needed in this area, particularly double-blind RCTs in which biologic therapy or an immunosuppressant other than azathioprine is withdrawn.

Current Practices for Therapeutic Drug Monitoring of Biopharmaceuticals in Pediatrics

Biopharmaceuticals have recently emerged as effective treatments for refractory pediatric autoimmune conditions. Several reports have shown a relationship between drug concentration, antidrug antibodies, and clinical response in these patients, strongly suggesting the potential interest, usefulness, and reliability of therapeutic drug monitoring (TDM) in children. This article reviews the current state of research in juvenile idiopathic arthritis, pediatric inflammatory bowel disease, and pediatric psoriasis from a TDM point of view. There is a remarkable lack of evidence-based data in pediatric patients, which is reflected throughout the article. Most investigations of TDM are focused on research of tumor necrosis factor alpha antagonists in inflammatory bowel disease, albeit preliminary publications are emerging from pediatric rheumatologists and dermatologists. To date, immunogenicity has been a primary concern, particularly regarding infliximab and adalimumab therapy in children, as it may lead to a loss of therapeutic response. Preliminary investigations show that adjusting the dose according to blood drug concentrations improves disease outcomes by overcoming antidrug antibodies, suggesting a crucial role for TDM. Patients who receive other drugs, such as etanercept, abatacept, or tocilizumab, could benefit from TDM because dosage can be optimized by adjusting it to the minimum effective dose.