Infliximab Top-down in Pediatric Crohn (ITSKids)

The purpose of this study is to determine whether a top-down treatment approach, prescribing infliximab and azathioprine at diagnose, yields better outcome in comparison to the usual step-up treatment approach, starting with prednison and azathioprine, in moderate-to-severe pediatric Crohn's disease (CD) patients.

Objective: The purpose of this study is to determine whether a top-down treatment approach, prescribing infliximab and azathioprine at diagnose, yields better outcome in comparison to the usual step-up treatment approach, starting with prednison and azathioprine, in moderate-to-severe pediatric Crohn's disease (CD) patients. Sample size: We will include 100 (2 x 50) patients. With these numbers a difference of 60% and 85% (= 25) can be shown at a power of 80% (2-sided α 0.05; nQuery Advisor). Study design: an international open-label randomised controlled trial Study population: Children (age 3-17 yrs) with new-onset, untreated, CD with moderate-to-severe disease activity Intervention: Patients will be randomised to either top-down IFX treatment or conventional step-up treatment. Treatment arm 1: Top-down IFX treatment will consist of a total of 5 IFX infusions of 5 mg/kg (IFX induction at week 0, 2 and 6, followed by 2 maintenance infusions every 8 weeks) combined with oral azathioprine (AZA) 2-3 mg/kg once daily. AZA therapy will continue after the last IFX infusion to maintain remission. Treatment arm 2: Step-up treatment will consist of standard induction treatment by oral prednisolone 1 mg/kg (maximum 40 mg) once daily for 4 weeks, followed by tapering in 6 weeks until stop. Prednisolone will be combined with oral AZA 2-3 mg, once daily, as maintenance treatment. Main study parameters/endpoints: Clinical remission at 52 weeks without need for additional IBD related therapy or surgery. Secondary endpoints include clinical response, remission and mucosal healing at week 10 and 52, growth and adverse events.

Infliximab and azathioprine; patients will receive 5 infliximab infusions of 5 mg/kg (IFX induction at week 0, 2 and 6, followed by 2 maintenance infusions every 8 weeks). IFX will be discontinued after 5 IFX infusions. Patients will also receive oral azathioprine 2-3 mg/kg, once daily as maintenance treatment.

Prednisolon and azathioprine; Patients will receive induction treatment with oral prednisolone 1 mg/kg (maximum 40 mg) once daily for 4 weeks, then tapering of prednisolone in 6 weeks until stop, and receive oral azathioprine 2-3 mg/kg, once daily as maintenance treatment.

Clinical remission is defined as a Pediatric Crohn's Disease Activity Index (wPCDAI) score of less than 10 points

Response is defined by a decrease in PCDAI score above 15 points compared to baseline. Remission is PCDAI<10

Therapy failure: primary non-response, loss of response according to wPCDAI and medication intolerance

Adverse events includes therapy side effects, disease complications (fistulas, abscesses, strictures, surgery, extra-intestinal manifestations)

Inclusion Criteria: Children (age 3-17 years, both male and female) with new-onset, untreated CD with moderate-to-severe disease activity assessed by a wPCDAI >40 will be eligible for inclusion after a diagnosis of CD was made based on the Porto criteria. Exclusion Criteria: Patients with the following characteristics will be excluded: immediate need for surgery, symptomatic stenosis or stricture in the bowel due to scarring, active perianal fistulas, severe co-morbidity, severe infection such as sepsis or opportunistic infections, positive stool culture, positive Clostridium difficile assay, positive tuberculin test or a chest radiograph consistent with tuberculosis or malignancy, those already started with CD specific therapy.