P365 Serum adalimumab levels predict successful remission and safe de-intensification in inflammatory bowel disease patients in clinical practice

Abstract

Background: Little is known about the association between the phar-macokinetic features of adalimumab (ADL) and disease outcome in patients with inflammatory bowel disease (IBD). Aim(s): To assess the association between random serum ADL levels and clinical and bio-chemical remission and between ADL levels and clinical decision making in daily practice. To determine the cut-off value for successful dose reduction in IBD patients treated with ADL. Method(s): We conducted a prospective cohort study (18 months) of IBD patients who received maintenance therapy with ADA (at least 12 weeks). Result(s): Data were available for 157 serum samples from 87 patients. Serum ADL levels were associated with clinical remission: median 9.2 [xg/ml vs 6.0 [ig/ml for Crohn's disease patients with active disease (p=0.009) and 14.4 [ig/ml vs 5.2 [ig/ml for ulcerative colitis patients with active disease (p=0.002) (Fig. 1). Serum ADL levels were 9.2 [xg/ml for patients with a normal C-reactive protein (CRP) value (<5mg/l) and 5.2 [xg/ml for patients with a high CRP value (p=0.002) (Fig. 2). ADL levels were significantly associated with normal fecal calpro-tectin values (<80 ng/g) (10.8 [xg/ml vs 7.6, respectively, p=0.038) (Fig. 3). We analyzed the clinical decisions taken on the basis of serum ADA levels according to the cut-off values described in previous studies (8 (xg/ml). [Figure Presented] successful de-intensification compared with the group in which doses remained unchanged (AUC 0.88; 95% CI: 0.81-0.95; p<0.001). The cut-off value for successful de-intensification was 12.2 mug/ml. Conclusion(s): Higher ADL levels were significantly associated with clinical and biochemical remission. Our results, which were obtained under conditions of daily clinical practice, suggest that an ADL cutoff of 12.2 mug/ml is appropriate for successful dose reduction in IBD patients treated with ADL.