P527 Low adalimumab serum levels at Week 4 provoke immunogenicity and influence therapy outcome in anti-TNF naïve Crohn’s disease patients

Abstract

Abstracts of the 13 th Congress of ECCO -European Crohn's and Colitis Organisation S373severe disease on US with BWT ≥7mm and/or sonographic complications (strictures/penetrating complications). Background: Adalimumab (ADM) serum levels (SL) during maintenance are associated with treatment outcome and need for doseescalation in Crohn's disease (CD) patients. Little is known about the clinical relevance of proactive testing of ADM SL during induction. We evaluated correlation between ADM SL at Week 4, ADM anti-drug antibody (ADA) presence and outcome. Methods: Serum samples from biologically naïve CD patients were prospectively collected at trough at Weeks 4 and 12 after ADM initiation. Clinical remission was defined as an average daily stool frequency ≤2.8 and an average abdominal pain score ≤1. In patients with an elevated baseline C-reactive protein (CRP), biochemical remission was defined as a CRP ≤5.0 mg/l and response as a decrease of at least 50% or CRP normalisation. ADM SL were measured with a novel ADM RIDA Conclusions