Impact of Exclusion Diet in Addition to Anti-TNF Therapy in Crohn's Disease and Ulcerative Colitis: a Prospective, Randomized, Double-arm, Open-label Study (IDEA-TNF)

Impact of Diet on the Effectiveness of Anti-TNF Therapy in Inflammatory Bowel Disease: a Prospective, Randomized, Double Arm, Open-label Study

This clinical study protocol aims to prospectively compare the efficacy of standard therapy with anti-TNF agents combined with the Crohn's Disease Exclusion Diet (CDED) versus anti-TNF therapy alone in adult patients with active Crohn's disease or ulcerative colitis.

The study will involve patients starting therapy with anti-TNF agents due to active Crohn's disease or ulcerative colitis as per standard clinical practice and in accordance with European (ECCO) guidelines.

One group will receive standard medical therapy only, the other will additionally receive dietary advice on how to adhere on a specific exclusion diet, the CDED.

By prospectively evaluating the impact of this combined approach, the study seeks to provide evidence on whether CDED can improve response to treatment and therefore improve quality of life for patients with Crohn's disease and ulcerative colitis.

Study Overview

• Status: Recruiting
• Conditions: Crohn Disease (CD); Ulcerative Colitis (UC)
• Intervention / Treatment: Combination product: CDED (Crohn's Disease Exclusion Diet) in addition to anti-TNF therapy; Drug: Anti-TNF Therapy

Detailed Description

This is a prospective interventional, single-center, double-group, open-label study.

Primary objective is to compare the efficacy of CDED in addition to anti-TNF therapy in active CD and UC versus anti-TNF therapy alone.

Secondary objective are:

• Endoscopic response
• Endoscopic remission
• Early and late efficacy and persistence of benefits
• Biochemical response
• Sonographic improvement
• Tolerability and compliance to the Crohn's Disease ExclusionDiet (CDED)
• Quality of life-Safety of the combination of biological therapy and CDED. The subjects considered are adult patients diagnosed with moderate-to-severe Crohn's disease or moderate-to-severe ulcerative colitis who are starting therapy with an approved anti-TNF agent (infliximab and adalimumab for both UC and CD, and golimumab only for UC).

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tommaso Lorenzo Parigi, MD; Phone Number: +39 02 2643 2756; Email: parigi.tommaso@hsr.it
• Study Contact Backup: Name: Annunziata Bruno, MS; Phone Number: +39 02 2643 2756; Email: bruno.annunziata@hsr.it

Study Locations

• Italy
  • Michigan
    • Milan, Michigan, Italy, 20132
      • Recruiting
      • IRCCS Ospedale San Raffaele
      • Contact: Tommaso Lorenzo Parigi, MD; Phone Number: +39 02 2643 2756; Email: parigi.tommaso@hsr.it
      • Contact: Annunziata Bruno, MS; Phone Number: +39 02 2643 2756; Email: bruno.annunziata@hsr.it
      • Principal Investigator: Tommaso Lorenzo Parigi, MD
      • Sub-Investigator: Mariangela Allocca, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Participant is willing and able to give informed consent forparticipation in the study
2. Males or Females, Adults aged 18 years or older
3. Confirmed diagnosis of moderate-to-severe Crohn's disease orulcerative colitis
4. Patients who are planned to start anti-TNF therapy
5. Ability and willingness to comply with the Crohn's DiseaseExclusion Diet (CDED)

Exclusion Criteria:

1. Patients with undetermined inflammatory bowel disease
2. Patients with metabolic or gastrointestinal conditions that couldinterfere or are incompatible with the study intervention (e.i.celiac disease, diabetes etc)
3. Patients with a body-mass index lower than 17 or greater than30
4. Patients who previously underwent intestinal resectionirrespective of cause
5. Patients currently on exclusive enteral nutrition (EEN)
6. Patients who have previously used or are currently adhering toCDED
7. Pregnant or breastfeeding women
8. Patients with a history of severe allergic reactions orintolerance to any food recommended in CDED
9. Patients with significant comorbidities that may interfere withthe study or pose a risk to the participant
10. Inability or unwillingness to comply with study protocols orfollow-up schedules

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control group; The control group will receive only anti-TNF therapy as per the standard of care and guidelines recommendation	Drug: Anti-TNF Therapy; The control group will receive only anti-TNF therapy as per standard of care. This therapy is recommended by guidelines and is the cornerstone of treatment of Crohn's disease and ulcerative colitis.
Experimental: Intervention group; Patients who accept participation and are randomized to receive dietary advice on the CDED diet will be included in the intervention group.	Combination product: CDED (Crohn's Disease Exclusion Diet) in addition to anti-TNF therapy; Patients in the experimental group will receive professional dietary advice on how to adhere to CDED for 12 weeks, in addition to anti-TNF therapy while patients in the control group will receive only anti-TNF therapy for the entire duration of the study. Diet adherence is completely voluntary and is not enforced in any way. CDED is divided into 3 phases, the first two, grouped as the induction phase, with 6 weeks of strict diet and 6 weeks to gradual food reintroduction, followed by 12 weeks of patients follow-up. Five foods (chicken, eggs, potatoes, apple and bananas) are permitted at the start of the diet; the patient can then choose to consume a range of permitted foods at will, the variability of which increases after the first six weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Efficacy of CDED in addition to anti-TNF therapy in active CD and UC versus anti-TNF therapy	Rate of symptomatic remission (Harvey - Bradshaw Index <5 for CD or Partial Mayo Score <2) for UC	Week 14/16

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Endoscopic response and endoscopic remission	Rate of endoscopic response for CD (SES-CD score reduction of 25% or more and of 50% or more from baseline) and for UC (endoscopic Mayo score reduction of at least 1 or more points); Rate of endoscopic remission for CD (SES-CD score ≤3) and for UC (Mayo endoscopic score ≤1)	Week 24
Early and late efficacy and persistence of benefits	Rate of symptomatic remission (Harvey- Bradshaw Index < 5 and Partial Mayo Score <2) at week 6 and 24	Week 6/ Week 24
Biochemical response	Change in C-reactive protein (CRP) levels from baseline; Change in fecal calprotectin levels from baseline	Week 6, 14/16, 24
Sonographic improvement	Change in BUSS (for CD) or MUC (for UC) from baseline; Rate of patients in transmural response (bowel wall thickness ≤3mm and no increase in bowel wall flow)	Week 6, 14/16, 24
Tolerability and compliance to the Crohn's Disease Exclusion Diet (CDED)	Percentage of patients self-reporting adherence to CDED	Week 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
Quality of life assessed using the Short-IBD-Q questionnaire	Change in Short-IBDQ questionnare score. Quality of life will be assessed using the validated Italian translation of the Short-IBD-Q questionnaire	Week 14/16, week 24
Safety of the combination of biological therapy and CDED	Incidence and type of adverse events during the study period	From baseline until the end of the study

Collaborators and Investigators

• Sponsor: IRCCS Ospedale San Raffaele
• Investigators: Principal Investigator: Tommaso Lorenzo Parigi, MD, IRCCS Ospedale San Raffaele

Study record dates

Study Major Dates

• Study Start (Actual): May 22, 2025
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): October 1, 2027

Study Registration Dates

• First Submitted: February 2, 2025
• First Submitted That Met QC Criteria: March 19, 2025
• First Posted (Actual): March 26, 2025

Study Record Updates

• Last Update Posted (Actual): January 22, 2026
• Last Update Submitted That Met QC Criteria: January 20, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Inflammatory Bowel Disease; Anti-TNF; Ulcerative colitis; Crohn; Crohn's Disease Exclusion Diet
• Additional Relevant MeSH Terms: Intestinal Diseases; Digestive System Diseases; Gastrointestinal Diseases; Colonic Diseases; Gastroenteritis; Colitis; Colitis, Ulcerative; Crohn Disease; Inflammatory Bowel Diseases
• Other Study ID Numbers: IDEA-TNF

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No