Children with Crohn's disease (CD), a type of Inflammatory Bowel Disease (IBD), often face serious health challenges, including poor growth, frequent hospital stays, and long-term medication use. Although biologic drugs like infliximab, an anti-TNFα (Tumor necrosis factor α) medication, have improved treatment, they don't work for everyone: many children still experience symptoms or disease flare-ups. Nutritional therapies, especially the Crohn's Disease Exclusion Diet (CDED), may help improve treatment outcomes. This study will assess whether starting CDED at the same time as infliximab leads to better responses to treatment. The goal of this study is to improve how well children respond to therapy, reduce drug exposure, and support better long-term health.
This open-label, randomized, controlled interventional study will evaluate the effectiveness of combining nutritional therapy (modified Crohn's Disease Exclusion Diet; mCDED) with infliximab (IFX) in pediatric patients with luminal Crohn's disease (CD), compared to IFX alone. The investigators hypothesize that initiating mCDED at the start of IFX therapy will enhance clinical response by the time the first IFX maintenance dose is given (week 12), and increase clinical and biochemical remission rates at 1 year (week 52). Participation will last up to 16 months and includes a pre-randomization phase of up to 4 months (for baseline sample and data collection), and 12 months of intervention. After randomization (T0), participants assigned to the intervention arm will follow a standardized IFX infusion schedule and begin the mCDED with the support of a dietitian. Participants in the control arm will follow the same IFX schedule and meet with a dietitian who will review their usual eating habits, but they will not be asked to follow any dietary advice. A total of 140 pediatric CD patients (70 per arm) will be recruited from the lead site (Vancouver) and 7-9 additional participating sites (Montreal, Ottawa, Toronto, Halifax, Calgary, Edmonton, London, Hamilton) within the Canadian Children Inflammatory Bowel Disease Network (CIDsCaNN). The following samples and data will be collected: 1. 3-day diet record (3DDR) - Completed by both arms at weeks 1, 12, 24 and 52 to assess dietary intake differences and dietary adherence to mCDED. 2. 24-hour diet recall - Conducted by a dietitian to assess dietary adequacy of both groups at weeks 1, 2 (for intervention group only), 6, 12, and 24. 3. CDED diet habits questionnaire - Completed by both groups at weeks 1 and 52 to assess how their diet aligns with the mCDED and to evaluate any changes in dietary habits. 4. CDED adherence questionnaire - Completed by the intervention group only at weeks 2, 6, 12, and 24. 5. KIDMED questionnaire (Mediterranean Diet Quality Index in children) - Completed by both groups at weeks 1 and 52 to assess adherence to a healthy diet and good dietary habits. 7\) Paediatric Yorkhill Malnutrition Score (PYMS) - At pre-randomization assessment, weeks 24 and 52, to assess malnutrition. 8\) Clinical and Biochemical Data - Weighted paediatric Crohn's disease activity index (wPCDAI), physician global assessment (PGA), C-reactive protein (CRP), ESR (Erythrocyte Sedimentation Rate), Fecal calprotectin (FCP) and hematological data (Complete Blood Count \[CBC\]) collected at pre-randomization assessment, weeks 1, 6, 12, 24 and 52. 9\) Anthropometric data (body mass index \[BMI\], growth velocity) - Assessed over study at pre-randomization assessment, weeks 1, 2, 6, 12, 24, 36 and 52. 10\) Nutritional status (Albumin, Ferritin, B12, Vitamin D levels) - Measured in blood at weeks 1, 6, 12, 24 and 52 11) IFX trough levels - Measured in blood at weeks 6, 12, 24 and 52. 12) Optional blood sample - Participants will have the option to provide a blood sample during the pre-randomization assessment for genetic testing to investigate genetic variants that may influence response to IFX, including but not limited to HLADQA1\*05 (major histocompatibility complex, class II, DQ alpha 1). 13\) Magnetic Resonance Elastography (MRE) - Performed at Baseline (within 4 months prior to randomization and starting therapy) and at week 52 (±4 weeks) and/or when clinically indicated to assess disease activity. 14\) Intestinal ultrasound (IUS) - Performed at Baseline (T-2, within 4 months prior to randomization and starting therapy), weeks 12 (±2 weeks), 24 (±4 weeks) and 52 (±4 weeks) to assess disease activity (transmural intestinal inflammation). 15\) Colonoscopy - At Baseline (within 4 months prior to randomization and starting therapy) and at week 52 (±4 weeks) to assess disease activity (SES-CD; Simple endoscopic score for Crohn's disease). While not mandatory, it is highly encouraged. In the absence of a colonoscopy, a composite score will be generated. If a colonoscopy is performed, mucosal washes and intestinal biopsies will be collected for research purpose. 16\) Fecal samples - Collected without preservatives by participants at weeks 1, 2, 6, 12, 24, and 52 for longitudinal microbiota analysis, in vitro microbiota culturing, and fecal transplantation into germ-free recipient mice. 17\) IMPACT-III - Quality of life survey completed by all participants at weeks 1, 12 and 52.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
140
modified Crohn's Disease Exclusion Diet (mCDED) ; Diet intervention
The University of British Columbia
Vancouver, British Columbia, Canada
Clinical and biochemical response at the first infliximab (IFX) maintenance dose (week 12) in participants receiving mCDED alongside IFX compared with participants receiving IFX alone.
Clinical response: defined as mild or inactive clinical disease (at least a 17.5-points decrease in weighted paediatric Crohn's disease activity index (wPCDAI) from baseline, with a score \< 40), physician global assessment (PGA) of inactive or mild disease activity, off steroids, continuation on the same anti-TNFα dose, and remaining surgery-free. Biochemical response: Defined as at least a 50% decrease in fecal calprotectin (FCP) levels compared to baseline. wPCDAI ranges from 0 to 125, with higher scores indicating greater disease activity. PGA ranges from 0 to 10, with higher scores indicating greater disease activity.
Time frame: 12 weeks
Steroid-free clinical and biochemical remission at week 12 in participants receiving mCDED alongside IFX compared with participants receiving IFX alone.
Steroid-free clinical remission (SFCR): defined as an inactive disease (wPCDAI \<12.5), PGA of inactive disease, no steroid use in the preceding 28 days, continuation on IFX and remaining surgery-free. Biochemical remission: defined as a normalization of C-reactive protein (CRP) (\< 5 mg/L) and Erythrocyte Sedimentation Rate (ESR) (\< 15-20 mm/h, male \& female respectively) if available, and FCP level \< 250 µg/g. wPCDAI ranges from 0 to 125, with higher scores indicating greater disease activity. PGA ranges from 0 to 10, with higher scores indicating greater disease activity.
Time frame: 12 weeks
Steroid-free clinical and biochemical response at weeks 24 and 52 in participants receiving mCDED alongside IFX compared with participants receiving IFX alone.
Steroid-free clinical response: defined as mild or inactive clinical disease (at least a 17.5-points decrease in weighted paediatric Crohn's disease activity index (wPCDAI) from baseline, with a score \< 40), physician global assessment (PGA) of inactive or mild disease activity, off steroids, continuation on the same anti-TNFα dose, and remaining surgery-free. Biochemical response: Defined as at least a 50% decrease in fecal calprotectin (FCP) levels compared to baseline. wPCDAI ranges from 0 to 125, with higher scores indicating greater disease activity. PGA ranges from 0 to 10, with higher scores indicating greater disease activity.
Time frame: 24 and 52 weeks
Proportion of participants achieving steroid-free clinical and biochemical remission at weeks 24 and 52 in participants receiving mCDED alongside IFX compared with participants receiving IFX alone.
Steroid-free clinical remission (SFCR): defined as an inactive disease (wPCDAI \<12.5), PGA of inactive disease, no steroid use in the preceding 28 days, continuation on IFX and remaining surgery-free. Biochemical remission: defined as a normalization of C-reactive protein (CRP) (\< 5 mg/L) and Erythrocyte Sedimentation Rate (ESR) (\< 15-20 mm/h, male \& female respectively) if available, and FCP level \< 250 µg/g. wPCDAI ranges from 0 to 125, with higher scores indicating greater disease activity. PGA ranges from 0 to 10, with higher scores indicating greater disease activity.
Time frame: weeks 24 and 52
1-year composite score of clinical remission and biochemical remission in addition to meeting criteria for steroid-free clinical remission adjusted for week 12 IFX trough level.
1-year composite score remission: defined as the concurrent achievement of clinical remission and biochemical remission at the 12-month follow-up. This score will be adjusted by the IFX blood level (in µg/mL) measured at week 12. Steroid-free clinical remission (SFCR): defined as an inactive disease (wPCDAI \<12.5), PGA of inactive disease, no steroid use in the preceding 28 days, continuation on IFX and remaining surgery-free. Biochemical remission: defined as a normalization of C-reactive protein (CRP) (\< 5 mg/L) and Erythrocyte Sedimentation Rate (ESR) (\< 15-20 mm/h) if available, and FCP level \< 250 µg/g. 1-year composite score: 0 = no remission 1. = clinical or biochemical remission 2. = clinical and biochemical remission
Time frame: Week 52
Endoscopic response and endoscopic remission at week 52 in participants receiving mCDED alongside infliximab (IFX) compared with participants receiving IFX alone.
Endoscopic response: defined as at least a 50% reduction from baseline in Simple endoscopic score for Crohn's disease (SES-CD), or for patients with isolated ileal disease and a baseline SES-CD of 4, at least a 2-point reduction from baseline. Endoscopic remission: defined as an SES-CD score lower or equal to 4, with at least a 2-point reduction from baseline and no sub-score \> 1. Deep remission as per wPCDAI and endoscopic remission. SES-CD ranges from 0 to 56, with higher scores indicating greater disease activity.
Time frame: Week 52
Frequency of progression from inflammatory phenotype (B1) to complicated disease (B2, B3, or B2/B3) in participants receiving mCDED alongside IFX compared with participants receiving IFX alone.
Disease progression will be evaluated by assessing whether participants with an initial inflammatory phenotype (B1) develop a stricturing (B2), penetrating (B3), or mixed (B2/B3) phenotype during follow-up, based on the Montreal classification. Progression will be confirmed through cross-sectional imaging (MRE, or IUS), colonoscopy, or surgical findings showing luminal narrowing, pre-stenotic dilation, or fistula/abscess formation. Imaging will be performed at baseline and as clinically indicated. The number of participants progressing from B1 to B2/B3 and time to first progression from B1 to B2/B3 will be recorded.
Time frame: Week 52
Long-term dietary habits in participants receiving dietary therapy, including consumption of ultra-processed foods (UPFs) and adherence to healthy dietary patterns.
Participants will fill out the KIDMED questionnaire at baseline and at week 52. The KIDMED score is a 16-item questionnaire used to assess a child or adolescent's adherence to the Mediterranean Diet (MD). The total score ranges from -4 to +12. Value of the KID-MED score: ≤3, very-low-quality diet; 4-7, need to improve the food pattern to adjust it to the Mediterranean one; ≥8, optimal Mediterranean diet.
Time frame: Week 52
Association between ongoing adherence to reduced ultra-processed food (UPF) consumption and long-term biologic response.
The relationship between KIDMED score and clinical and biochemical response or remission will be investigated. The KIDMED score is a 16-item questionnaire used to assess a child or adolescent's adherence to the Mediterranean Diet (MD). The total score ranges from -4 to +12. Value of the KID-MED score: ≤3, very-low-quality diet; 4-7, need to improve the food pattern to adjust it to the Mediterranean one; ≥8, optimal Mediterranean diet. Clinical response: defined as mild or inactive clinical disease (at least a 17.5-points decrease in weighted paediatric Crohn's disease activity index (wPCDAI) from baseline, with a score \< 40), physician global assessment (PGA) of inactive or mild disease activity, off steroids, continuation on the same anti-TNFα dose, and remaining surgery-free. Biochemical response: Defined as at least a 50% decrease in fecal calprotectin (FCP) levels compared to baseline.
Time frame: Week 52
Microbial changes induced by the dietary intervention and their association with clinical and biochemical response.
Microbial analyses that will be undertaken for each sample type are as follows: Stool: * Metagenomics (Shotgun sequencing, ITS sequencing for fungal analysis) * Metaproteomics and metabolomics (Host, microbial, and dietary protein analysis, microbial metabolite analysis) * Anaerobic culturing (Simulate gut environment, use dietary substrates to target key microbes) Biopsy specimens: * RNA-seq, transcriptomics (Gene expression profiling analysis, disease marker identification) * Metagenomics * Metaproteomics and metabolomics Intestinal washings: * Metagenomics * Metaproteomics and metabolomics
Time frame: Weeks 12, 24 and 52
Association between baseline microbiome profiles and therapeutic outcomes at the first IFX maintenance dose (week 12) using compositional analyses and machine learning (ML) approaches.
Multi-modal integrative analysis will combine metagenomic, metaproteomic, and metabolomic data with diet (mCDED vs. regular diet), endoscopic and clinical scores (SES-CD, PCDAI), biochemical markers (FCP, ESR, CRP), quality of life, and anthropometric data. Univariate analyses will be performed to test associations between each quantitative measure of disease activity and each dataset (taxonomic and functional tables), identifying both positive and negative correlations. Sparse Partial Least Squares Discriminant Analysis (sPLS-DA; http://mixomics.org/) will be used for feature selection and dimensionality reduction to identify the most informative predictors. These features will then be used to train predictive models with Random Forest classifiers and artificial neural networks (ANN), providing complementary approaches for robust prediction. Model performance and generalizability will be evaluated using repeated cross-validation (20 × 5-fold).
Time frame: Week 12
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