P537 Adalimumab: Relevance of drug trough levels and antibodies assessment in the prognosis of Crohn’s disease

Abstract Background Monitoring of infliximab therapy in inflammatory bowel disease (IBD) is well established. As for adalimumab, there is less consolidated data. This study aimed to evaluate the usefulness of adalimumab trough levels (ATL) and serum anti-adalimumab antibodies (AAA) in the control of Crohn's disease (CD). Methods This is a retrospective study assessing patients with CD treated with adalimumab followed in a tertiary hospital. Remission was defined as the absence of symptoms and C-reactive protein (CRP) value ≤ 0.5 mg/dl. All patients were on treatment for at least eight weeks. Drug quantification: ATL was always measured immediately before the next drug administration (the patients with ATL between two drug administrations or after taking the drug were exclude). Statistical significance was considered when p