Biomarkers predicting the effect of anti-TNF treatment in pediatric and adult inflammatory bowel disease.

Anti-TNF treatment (infliximab (IFX), adalimumab (ADA)) has become standard
therapy for refractory pediatric and adult Crohn*s disease (CD) patients, and
is used for the induction (primary response) and maintenance of remission. When
effective, clinical and endoscopic remission is reached within weeks. However,
primary non-response is observed in 20% of pediatric patients, and in 40% of
adult CD patients, suggesting a more robust acute response to anti-TNFa therapy
in children as compared to adults. During maintenance treatment, 60 - 80% of
patients have secondary loss of response, necessitating dose adjustments to
maintain clinical response. Anti-TNF treatment is also increasingly used in
ulcerative colitis, and has been shown to induce remission in active disease.
For UC, the comparison between the efficacy in children versus adults is more
difficult to report as studies in children are scarce. Anti-TNF treatment is
associated with rare but potentially fatal side effects, infusion reactions,
and is an expensive treatment. To avoid overtreatment it is necessary to early
identify non-responders to treatment, and therefore it is important to develop
predictive biomarkers of treatment response.

Main objective: To validate novel biomarkers that can predict (non-)response to
anti-TNF induction treatment in pediatric and adult IBD patients.
Secondary objectives: To accurately describe pharmacokinetics of IFX and ADA in
pediatric and adult IBD patients; to evaluate differences between pediatric and
adult IBD regarding anti-TNF treatment behavior and expression of biomarkers;
to evaluate the disease course in non-responders to anti-TNF induction therapy.

Single-center, prospective cohort study, with a follow-up period of 1 year.

Patients will not benefit from participating in this study. Study visits will
coincide with regular visits to the infusion department and/or outpatient
clinic, and extra blood will be withdrawn during routine blood tests only,
resulting in a minimal extra burden for patients. In addition buccal epithelium
will be collected. Our study population will partly consist of pediatric
patients, as pediatric IBD seems to represent a specific group of IBD patients
with a distinct disease phenotype and clinical presentation compared with
adults.