Maarten Cozijnsen

100 Results In total 15 Dutch centers participated, i.e. 10 centers of the Dutch pediatric IBD working group (KiCC) and 5 additional centers. Between 2005 and 2013, 59 pediatric CD patients had switched from infliximab to adalimumab of whom 53 met the inclusion and exclusion criteria. Twelve of the 15 centers kept record of the number of CD patients that received IFX during this period: 351 received infliximab of whom 55 switched to adalimumab (median switching rate 13.3% (IQR 9.8-18.1)). The patients characteristics are displayed in Table 1. Table 1. Patient characteristics n(%) or median (IQR) Total included patients 53 Gender Female 27 (50.9%) Age At diagnosis 11 (8-13) At adalimumab commencement 14 (13-16) Disease location* Ileocecal (L1) 6 (11.3%) Colonic (L2) 11 (20.8%) Both ileal and colonic (L3) 36 (67.9%) Disease behaviour* Not stricturing nor penetrating (B1) 42 (79.2%) Stricturing (B2) 8 (15.1%) Penetrating (B3) 1 (1.9%) Both penetrating and stricturing (B4) 2 (3.8%) History of perianal disease 19 (35.8%) Growth delay at diagnosis* 20 (37.7%) Prior treatment Exclusive enteral nutrition 32 (60.4%) Steroids 50 (94.3%) Mesalazine 27 (50.9%) Purine antimetabolites 52 (98.1%) Methotrexate 26 (49.1%) Infliximab treatment duration (months) 15.7 (10.8-25.8) Type of infliximab failure Lost response 34 (64.2%) Allergic reaction 11 (20.8%) Side effects 5 (9.4%) Non-response 3 (5.7%) ATI presence Tested 38 (71.7%) Positive (>15AE/ml) 21 (55.3%) History of CD related surgery 12 (22.6%) ATI=antibodies to infliximab. *As defined by the Paris Classification(20)