The Role of Combination Therapy in Pediatric Inflammatory Bowel Disease: A Clinical Report from the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition

Infliximab Monotherapy vs Combination Therapy for Pediatric Crohn's Disease Exhibit Similar Pharmacokinetics

BACKGROUND

The use of concomitant azathioprine may improve efficacy and pharmacokinetic (PK) properties of infliximab (IFX) but is also associated with an increased risk of adverse events. Proactive therapeutic drug monitoring (pTDM) of IFX monotherapy is an alternative strategy to improve PK. The aim of this study was to evaluate whether IFX with an immunomodulator (combo) has PK benefits over IFX-pTDM (mono) in pediatric Crohn's disease (CD).

METHODS

This PK analysis included pediatric CD patients who started either IFX combo (TISKids study) or IFX mono with pTDM (REFINE cohort). Combo and mono IFX trough levels (TLs) and antibodies-to-infliximab were assessed at infusion 3, 4, and 5. A population PK model was built to compare IFX PK outcomes (clearance [CL], TLs and cumulative exposure) between combo and mono groups at infusion 4 and 5. Clinical response and steroid-free clinical remission (SFCR) was assessed at infusion 4 and 5.

RESULTS

This study included 128 pediatric CD patients (66 mono and 62 combo). At infusion 5, there was no significant difference between mono and combo median TLs 4.1 µg/mL (2.1, 7.8) vs 5.9 µg/mL (3.2, 9.4; P = .14) or median CL 0.26 L/d (0.21, 0.32) vs 0.26 L/d (0.21, 0.33; P = .81). Mono patients had a lower SFCR rate at infusion 5 (53% [31 of 59] vs 80% [32 of 40]; P = .01). Clinical response rates were significantly higher among combo than mono patients at both infusion 4 and 5.

CONCLUSIONS

This study suggests that there are no PK differences (TLs and CL) between combo and mono therapy in pediatric CD patients who started IFX.

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.

Weekly Folic Acid Is a Convenient and Well-Tolerated Alternative to Daily Dosing in Pediatric Patients with Inflammatory Bowel Disease on Methotrexate

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic autoimmune disorder that affects the gastrointestinal tract. Methotrexate is a folate analog immunosuppressant used in the management of pediatric IBD. Daily folic acid supplementation is currently recommended to prevent folate deficiency and reduce the side effects of methotrexate such as nausea, stomatitis, and hepatotoxicity. The aim of this study was to evaluate the safety and adequacy of once-weekly folic acid supplementation in pediatric inflammatory bowel disease patients taking methotrexate.

METHODS

In this single-arm observational study, we included subjects aged 2-21 years old with inflammatory bowel disease who were receiving a standard oral methotrexate dose of 10-15 mg/m² weekly and 800 mcg of folic acid daily. Baseline folate level, blood counts and chemistries, and a symptom questionnaire were completed. Subjects were switched to weekly 800 mcg of folic acid to be taken in conjunction with methotrexate. Monthly phone calls with a standardized questionnaire were used to assess compliance and any change in symptoms. Follow-up blood tests were obtained 6 months after enrollment. Normal folate level was defined as >5.38 ng/mL.

RESULTS

Thirty-one subjects were enrolled. Five subjects were withdrawn due to poor compliance or transition to adult gastroenterology. Twenty-one (81%) subjects had Crohn's disease (17 with ileal involvement) and five (19%) had ulcerative colitis. Twelve (39%) subjects were on methotrexate as a combination therapy with a biologic agent. At the 6-month follow-up visit, all subjects had stable folic acid levels (>5.38 μg/L) without macrocytic anemia. Monthly questionnaires found no increased symptoms, and there were no adverse events.

CONCLUSIONS

Once weekly folic acid supplementation at a dose commonly found in a multivitamin may be sufficient to maintain normal folate levels without the development of adverse symptoms in pediatric patients with inflammatory bowel disease on methotrexate therapy.

Withdrawal of Combination Immunotherapy in Paediatric Inflammatory Bowel Disease-An International Survey of Practice

OBJECTIVES

To assess current practices around the use of combination immunosuppression in paediatric inflammatory bowel disease (PIBD) with a focus on the subsequent withdrawal process.

METHODS

A web-based, 43-question survey.

RESULTS

Surveys were completed by 70 paediatric gastroenterologists (PGs) from 27 nations across Europe, North America, Oceania and Asia from 62 centres covering approximately 15,000 PIBD patients (median of 200 patients [interquartile range (IQR) 130-300] per centre). Routine use of co-immunosuppression was significantly higher with infliximab (IFX) versus adalimumab (ADL) ([61/70, 87.1%] compared with [23/70, 32.9%]; P < 0.01). Thiopurines (azathioprine [AZA] or 6-mercaptopurine) were the preferred option overall for co-immunosuppression. They were favoured with either IFX or ADL (76% and 77%, respectively) and in both ulcerative colitis (UC) and Crohn disease (CD) (84% and 69%) compared with methotrexate (MTX).Immunomodulators were the preferred choice as the initial drug to be withdrawn from the combination therapy rather than anti-tumour necrosis factor-alpha (anti-TNFα) therapy (59/67, 88% [P < 0.01]). The most common withdrawal time was after 6-12 months, with this decision usually based on clinical assessment rather than a scheduled withdrawal time (51/67, 76% vs 16/67, 24%). Indicators of mucosal healing and therapeutic drug monitoring results tended to be the most important "clinical factors" in the withdrawal decision (P = 0.05).

CONCLUSION

Most PG's favour initial withdrawal of immunomodulator (usually thiopurines) rather than biologic therapy in the step-down process, usually after 6-12 months based on sustained clinical remission. This survey precedes an in-depth, multicentre study of clinical outcomes of withdrawal of co-immunosuppression in PIBD.

Early Infliximab in Crohn's is associated with decreased intestinal surgery and similar health care costs

BACKGROUND

Using Infliximab early in Crohn's disease can provide a window of opportunity in children for restoration of growth and achievement of puberty. We aimed to compare clinical outcomes and costs of a retrospective pediatric Crohn's disease (pCD) cohort treated with early use Infliximab (EUI) within 12 months compared with later use Infliximab (LUI).

METHODS

Retrospective review of all children with pCD commenced on Infliximab was undertaken in a tertiary Australian pediatric center.

RESULTS

pCD progressing to Infliximab was identified in 70 children: 38 (54%) in the EUI cohort versus 32 (46%) in the LUI cohort. Intestinal surgery had a higher risk of occurring in EUI when compared with LUI (2 (5%) versus 9 (28%), HR 5.67 (95% CI 1.21-26.38); p = .027). No patients in EUI underwent intestinal surgery post Infliximab commencement compared with 3 (9%) in LUI (p = .09). Escalation of Infliximab in luminal Crohn's disease was not significantly different in EUI when compared with LUI (3 (10.3%) versus 9 (39.1%) (p = .1)). EUI was more frequently used than LUI in 2015-2018 (27 (71%) versus 14 (44%)) p = .029, with the inverse occurring in 2010-2014 (11 (29%) versus 18 (56%)). Hospital admissions per person per year in EUI and LUI were 43 (0.23 visits/person/year) versus 84 (0.67 visits/person/year); IRR 2.51 (95% CI 0.9-7.01); p = .078). Health costs were not significantly different between cohorts.

CONCLUSION

EUI in pCD is associated with an increased likelihood of being diagnosed in more recent years, less intestinal surgery and a trend toward decreased hospital admissions than LUI.

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.

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

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

Updates in diagnosis and management of inflammatory bowel disease

Worldwide incidence of inflammatory bowel disease (IBD) is stable in developed countries, but rising in developing countries. Presenting symptoms of IBD can be highly variable. New imaging modalities, a greater armamentarium of therapeutic options, and a greater understanding of complication risks have changed the diagnosis and management of pediatric inflammatory bowel diseases. Effective teamwork among those who care for pediatric patients with IBD minimizes complications and maximizes desired outcomes.

Longitudinal Barriers to Thiopurine Adherence in Adolescents With Inflammatory Bowel Diseases

Objectives

Cross-sectionally, more adherence barriers are associated with lower medication adherence. However, little is known about longitudinal associations between adherence barriers and adherence. Among adolescents with inflammatory bowel diseases (IBD), this study examined both (1) how time-varying self-reported adherence barriers affect daily thiopurine adherence and (2) how adherence barriers at baseline affect daily thiopurine adherence over a six-month period.

Methods

Eighty-one adolescents 11-18 years old prescribed a once-daily oral IBD maintenance medication participated in a six-month observational study. Adherence barriers were self-reported monthly via the Medication Adherence Measure (MAM): Medication Subscale. Daily adherence estimates were collected via Medication Event Monitoring System (MEMS) Track Caps.

Results

Generalized linear mixed modeling indicated that time alone did not significantly predict whether one was more likely to be adherent (p = .602). However, increasing adherence barriers lowered the likelihood that a participant would be adherent on a given day, and the interaction between time and barriers predicted likelihood of adherence on a given day (p < .01). Specifically, when participants reported no adherence barriers at baseline, adherence did not significantly change over time (p = .369). However, when barriers were endorsed, adherence decreased over time (p < .01).

Conclusions

Fewer adherence barriers over time predicted greater likelihood of adherence on a given day, which is consistent with previous cross-sectional research. Routine assessment of barriers to adherence over the course of adolescence is critical in addressing suboptimal adherence behavior in youth with IBD.

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.

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/).

Variation in Care in the Management of Children With Crohn's Disease: Data From a Multicenter Inception Cohort Study

BACKGROUND

Variation in care is common in medical practice. Reducing variation in care is shown to improve quality and increase favorable outcomes in chronic diseases. We sought to identify factors associated with variation in care in children with newly diagnosed Crohn's disease (CD).

METHODS

Prospectively collected data from a 28-site multicenter inception CD cohort were analyzed for variations in diagnostic modalities, treatment, and follow-up monitoring practices, along with complicated disease outcomes over 3 years in 1046 children. Generalized linear mixed effects models were used to investigate the intercenter variations in each outcome variable.

RESULTS

The mean age at diagnosis was 12 years, and 25.9% were nonwhite. The number of participants ranged from 5 to 112 per site. No variation existed in the initial diagnostic approach. When medication exposure was analyzed, steroid exposure varied from 28.6% to 96.9% (P < 0.01) within 90 days, but variation was not significant over a 3-year period (P = 0.13). Early anti-tumor necrosis factor (anti-TNF) exposure (within 90 days) varied from 2.1% to 65.7% (P < 0.01), but variation was not significant over a 3-year period (P > 0.99). Use of immunomodulators (IMs) varied among centers both within 90 days (P < 0.01) and during 3 years of follow-up (P < 0.01). A significant variation was seen at the geographic level with follow-up small bowel imaging and colonoscopy surveillance after initial therapy.

CONCLUSIONS

Intercenter variation in care was seen with the initial use of steroids and anti-TNF, but there was no difference in total 3-year exposure to these drugs. Variation in the initiation and long-term use of IMs was significant among sites, but further research with objective measures is needed to explain this variation of care. Small bowel imaging or repeat colonoscopy in CD patients was not uniformly performed across sites. As our data show the widespread existence of variation in care and disease monitoring at geographic levels among pediatric CD patients, future implementation of various practice strategies may help reduce the variation in care.

Early Biologic Treatment in Pediatric Crohn's Disease: Catching the Therapeutic Window of Opportunity in Early Disease by Treat-to-Target

The emergence of mucosal healing as a treatment goal that could modify the natural course of Crohn's disease and the accumulating evidence showing that biologics are most effective in achieving mucosal healing, along with the success of early treatment regimens for rheumatoid arthritis, have led to the identification of early Crohn's disease and development of the concept of catching the therapeutic window during the early disease course. Thus, an increasing number of pediatric gastroenterologists are adopting an early biologic treatment strategy with or without an immunomodulator. Although early biologic treatment is effective, cost and overtreatment are issues that limit its early use. Currently, there are insufficient data on who will benefit most from early biologics, as well as on who will not need early or even any biologics. For now, top-down biologics should be considered for patients with currently known high-risk factors of poor outcomes. For other patients, close, objective monitoring and accelerating the step-up process by means of a treat-to-target approach seems the best way to catch the therapeutic window in early pediatric Crohn's disease. The individual benefits of immunomodulator addition during early biologic treatment should be weighed against its risks and decision on early combination treatment should be made after comprehensive discussion with each patient and guardian.