This research is a multicenter French randomized and single blinded phase III clinical trial evaluating two treatment strategies among Crohn's disease (CD) patients. The main objective is to assess if the addition of Crohn's Disease Exclusion Diet (CDED) to ongoing standard medication is superior to reduce the rate of relapses over 12 months compared to standard medication alone in children/adolescents with unstable CD responding with remission after a 2-months course of CDED

Crohn's disease is a recurrent inflammatory disorder. Current treatment strategies aim reducing intestinal (and systemic) inflammation based on the use of Immunomodulators (IM) and biologics (B). However, some patients, particularly in the pediatric age group do not respond with remission to standard therapy and approximately 30% of patients lose response to efficient therapy. There is a clear unmet need for new treatment strategies. In addition, patients and families have a high degree of reluctance to use IM/B as life-long medication, particularly due to potential side effects including cancer, lymphomas, serious infections or drug-related immune diseases. This is of particular importance for children/adolescents with CD, potentially exposed over many decades to various IM/B. Experimental and epidemiological data indicate that the western life style and particularly modern food play a key role in the development of CD, probably via alteration of the intestinal barrier function and/or enforcing the intestinal dysbiosis. Based on these data and the observation that exclusive enteral nutrition is highly efficacious in inducing remission in active CD, nutritional therapies are more and more in the focus for the development of new treatment approaches.

The main objective is to assess if the addition of CDED to ongoing standard medication is superior to reduce the rate of relapses over 12 months compared to standard medication alone in children/adolescents with unstable CD responding with remission after a 2-months course of CDED.

To achieve this objective, eligible patients with active CD will participate to this study for a 13 months period. After a screening period, the patients will have a 2 months run-in phase where they will follow the CDED protocol, but continue their maintenance therapy, with the exception of corticosteroid that have to be tapered and stopped at the end of the 2 months.

Then, the patients responding to CDED during run-in will be randomized at M2 to one of the two treatment arms (CDED/Modulen™IBD® or Unrestricted food access) and will have 4 follow-up visits (M4, M6, M9 and M12)

Inclusion Criteria:

• Child/Adolescent aged 6-17 years with a confirmed diagnosis of CD (for at least 3 months) with an active disease (defined as: wPCDAI >12.5 or CRP > 2 times upper limit or calprotectin levels >250µg/g if available) despite anti-inflammatory (5-ASA and derivates), corticosteroids, immunomodulator (thiopurines or methotrexate) and/or biologic therapy (anti-TNF, anti-integrin anti-IL23 antibodies)
• For girls of childbearing age: a negative pregnancy test, and use of an effective method of contraception (abstinence, oral contraceptives, intra-uterine device, diaphragm with spermicide and condom)
• Patient willing to comply with daily intake of an exclusion diet
• Informed and signed consent of parents
• Patient affiliated to social security (or health insurance)

Exclusion Criteria:

• Active perianal fistulizing disease
• Internal fistula or evidence of un-drained and un-controlled abscess/phlegmon
• Patient who require CD-related surgical therapy
• Patient with known allergy to cow milk's proteins
• Patient incapable to follow CDED for a prolonged period
• Pregnancy, breastfeeding
• Patient already included in an interventional study