P604 Biologics with or without a combination with 5-ASA in ulcerative colitis: frequency of usage and effect on the course of disease in the Swiss IBD-Cohort study

Abstract Background 5-ASA remains the mainstay of therapy in mild-to-moderate ulcerative colitis (UC) enabling achievement of remission in between 50–75% of all patients. Combination of immunosuppressives (IS) has been found to be associated with a better outcome when compared with monotherapy. However, concerning 5-ASA combination with biologics, clinical practice is highly variable and the evidence on potential benefit is scarce. We aimed to evaluate the course of UC in patients being treated with a combination of 5-ASA and biologics vs. biologics alone. Methods We analysed the prospectively collected clinical data from all UC patients currently receiving biologic treatment and participating in the nation-wide Swiss IBD cohort study (SIBDCS) with vs. without 5-ASA co-treatment. Results At last clinical follow-up visit amongst the 366 identified UC patients with currently ongoing biologic treatment, 170 received 5-ASA co-treatment. Regarding key baseline characteristics, including sex, duration of disease and age at UC diagnosis, there were no differences between patients with vs. without 5-ASA. More patients with 5-ASA co-treatment were under concomitant therapy with IS and/or steroids. Moreover, disease activity in the 5-ASA combination group was significantly higher. No differences across groups were identified considering most recent, maximal and average levels of faecal calprotectin and leucocyte count, CRP and haemoglobin from blood samples. The occurrence of complications, for example, cancer, dysplasia, anaemia, osteoporosis, thromboembolism or extraintestinal manifestations (EIM) was similar. However, combination lead to less intestinal surgery. Population characteristics Biologics only (%) Biologics+5-ASA (%) Significant Number 196 (53.6) 170 (46.4) No Male 105 (53.6) 90 (52.9) No Female 91 (46.4) 80 (47.1) No MTWAI Median; IQR 5; 2–8 6; 4–10 p = 0.009 Immunomodulators 33 (16.8) 43 (25.3) p = 0.047 Steroid 39 (19.9) 55 (32.4) p = 0.007 Population characteristics Events Biologics only (%) Biologics+5-ASA (%) Significant Complications 114 (58.2) 107 (62.9) No EIM 105 (53.6) 93 (54.7) No Intestinal Surgery 16 (8.2) 5 (2.9) p = 0.032 Events Conclusions In our cohort, we found that UC patients under biologic therapy receiving 5-ASA co-treatment had a similar risk of complications or EIM while having a lower risk of colonic surgery. This being despite the fact that 5-ASA co-treated patients appear to reflect a subgroup of UC patients with a more sever