Abstracts of the 13 th Congress of ECCO – European Crohn’s and Colitis Organisation S405 P587 Drug survival of vedolizumab-treated infammatory bowel disease patients in a nationwide observational cohort study: ICC case series V. Biemans 1,2 *, C. van der Woude 3 , G. Dijkstra 4 , A. van der Meulen - de Jong 5 , B. Oldenburg 6 , N. de Boer 7 , C. Ponsioen 8 , A. de Vries 3 , J. Haans 2 , M. Pierik 2 , F. Hoentjen 9 , Dutch Initiative on Crohn and Colitis (ICC) 1 Radboudumc, Nijmegen, The Netherlands, 2 Maastricht University Medical Center (MUMC), Maastricht, The Netherlands, 3 Erasmus Medical Center, Rotterdam, The Netherlands, 4 University Medical Center Groningen, Groningen, The Netherlands, 5 Leiden University Medical Center (LUMC), Department of Gastroenterology and Hepatology, Leiden, The Netherlands, 6 University Medical Centre Utrecht, Utrecht, The Netherlands, 7 VU University Medical Centre Institute of Education, Department of Gastroenterology and Hepatology, Room J393, Amsterdam, The Netherlands, 8 Academic Medical Center (AMC), Department of Gastroenterology and Hepatology, Amsterdam, The Netherlands, 9 Radboudumc, Department of Gastroenterology and Hepatology, Nijmegen, The Netherlands Background: Vedolizumab (VDZ) is an antibody blocking the α4β7 integrin. Obtaining clinical response can take up to 3–6 months but once obtained seems to be well maintained at least throughout Week 52. However, real-life drug survival data beyond Week 52 are scarce. We therefore aimed to assess the drug survival in our 2-year obser- vational cohort of VDZ-treated infammatory bowel disease (IBD) patients. Methods: IBD patients who started VDZ in standard care were included. Patients were followed for 2 years using a systematic follow-up. We registered clinical disease activity (Harvey Bradshaw Index (HBI) and Short Clinical Colitis Activity Index (SCCAI)), infammatory biomarkers (CRP and faecal calprotectin), hospi- tal admissions, surgery, adverse events, and VDZ discontinuation. Dependent t test and Wilcoxon-signed rank test was used. Results: We enrolled 266 patients (172 CD, 153 female, aged 40.7 ± 15.1 years, disease duration 12.4 ± 9.5 years). 98.8% (CD) and 80.3% (UC) were biological-experienced. At baseline 29.7% of CD patients used concomitant corticosteroids, 19.2% immunosup- pressants (IMM) and 11.6% used both. For UC, 30.9% used corti- costeroids, 19.1% IMM and 18.1% both. A total of 121 (45.4%) IBD patients discontinued VDZ after a median follow-up of 25.7 (IQR 16.6–44.9) weeks for CD and 20.4 (14.9–30.4) weeks for UC. Main reason was primary non-response (71.1%), while adverse accounted for only 5%. Drug survival of VDZ did not differ between CD and UC patients (p = 0.49). VDZ discontinuation occurred for 66 (24.8%) IBD patients (55 no response, 3 adverse events) before 26 weeks of treatment. Beyond 52 weeks, 19 IBD patients (10 loss of response) discontinued VDZ. At Week 12 a difference in SCCAI was found between responders and non-responders (mean decrease of responders 3.4 ( ± 3) vs. 0.5 ( ± 3.7) non-responders p = 0.001). While the median treatment dura- tion was 20.4 weeks for UC non-responders (IQR 16.9–28.6). Conclusions: In a real-life IBD cohort, discontinuation rates for VDZ were 24.8% at Week 26, 38.3% at Week 52, and only 7.1% beyond Week 52. The main reason for all discontinuation was primary non- response (71.1%) in contrast to adverse events (5%). A decrease in SCCAI at Week 12 was predictive of clinical response to VDZ. Our long-term VDZ data show a reassuring drug survival and safety pro- fle beyond 52 weeks in daily clinical practice. P588 Switching from infiximab originator to a frst biosimilar is safe and effective: A single- centre series with through levels and anti-drug antibodies determination M. Daperno*, C. Guiotto, A. Italia, A. Lavagna, A. Negri, E. Ercole, M. Cosimato, C. Rigazio, R. Rocca Mauriziano Hospital, Gastroenterology Unit, Torino, Italy Background: Treatment of infammatory bowel disease (IBD) with anti-TNF drugs is hampered by notable costs. Over the past 2 years, CPT-13, a biosimilar infiximab, was released, on the market with substantial cost savings. Still the switch from originator to biosimilar is not systematically used due to fear of potential side effects. Aim of this study was to perspectively evaluate the effectiveness and safety of switch comparing to treatment outcomes in a consecutive series of patients treated only with biosimilar infiximab Methods: Cases were IBD patients undergoing originator infixi- mab, who were switched to CPT-13 since April 2016 (switch cases). Controls were patients who were started as frst biologic on CPT- 13, after its commercialisation in Italy (naive cases). Patients were enrolled in a longitudinal cohort study approved by Local Ethical Committee. At basal and following time points also samples for through levels (TL) and antibodies to infiximab (ATI) determination were drawn. Persistence in the treatment, adverse outcomes, infusion reaction and variations in TL and ATI were recorded and compared among the two groups. 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