Observational pharmacokinetics study of adalimumab in patients with active refractory Crohn's disease who are naïve to TNF antagonist therapy.

Adalimumab (ADM), a fully human tumor necrosis factor (TNF) antagonist, is effective for treating patients with Crohn's disease (CD). A correlation between concentration and effect was observed at distinct time points.

The aim was to evaluate the correlation of early longitudinal measurements of ADM with different biological markers for disease activity and induction and maintenance of clinical remission.

This is a prospective two-center open-label observational study in anti-TNF naïve patients with moderate to severe CD induced with ADM 160/80 mg at week 0 and 2 and 40 mg every 2 weeks in monotherapy. All patients should be in need for TNF antagonist therapy and should fulfill standard reimbursement criteria (Belgium). Serum samples were taken pre and post first injection and at weeks 1, 2, 3, 4, 12, 26 and 52. Following parameters were determined: C-reactive protein, albumin, TNF, ADM, antibodies to ADM, hemoglobin, platelet count and leukocyte count. Clinical response and remission was evaluated using the Harvey-Bradshaw index.

Inclusion Criteria:

• Patients with confirmed diagnosis of Crohn's disease, fulfilling the criteria for reimbursement (Belgium).
• Patients with active disease defined as a Harvey-Bradshaw index >4 and/or a C-reactive protein concentration >5 mg/l.
• Informed consent.

Exclusion Criteria:

• Patients with ulcerative colitis.
• Patients treated in placebo controlled trials.
• Patients unwilling to participate or withdrawing informed consent for this study.

Subjects who are naïve to TNF antagonist treatment and who will be started on adalimumab for treatment of active refractory Crohn's disease. All patients should be in need for TNF antagonist therapy and should fulfill standard reimbursement criteria (Belgium).