P471 Efficacy and safety of switching from reference infliximab to biosimilar infliximab in patients with inflammatory bowel disease: first French experience

Background: Infliximab is widely used for induction and maintenance therapy in inflammatory bowel diseases (IBD). Reference infliximab (Remicade®) was the first anti-TNF available, but its costs are high, placing a strain on healthcare system. CT-P13 is a biosimilar of Remicade® with expected savings of 30%. No data is available in France regarding switching from reference infliximab to CT-P13. We aimed to assess efficacy and safety of switching from reference infliximab to CT-P13 in IBD. Methods: From September 30, 2015 to March 30, 2016, a switch to CT-P13 (Inflectra®) and inclusion in a prospective observational study were proposed to all Remicade®-treated patients in our hospital (IBD, rheumatologic diseases, uveitis). Patients had to be on maintenance therapy (>3 Remicade® infusions) with stable treatment. Information was given and non-opposition was required. Data were collected in a anonymous questionnaire at baseline (2 infusions before the switch) and at each biosimilar infusion. Primary endpoint was the rate of patients still treated with Inflectra® after 3 infusions. Secondary endpoints were clinical activity, infliximab trough levels (ITL), anti-infliximab antibodies changes. A closeout visit was performed in July 2016. IBD activity was assessed with Mayo score [ulcerative colitis (UC)] or Harvey-Bradshaw [Crohn's disease (CD)]. ITL and anti-infliximab antibodies were measured before the first and the third CT-P13 infusion. Changes from baseline were analyzed with univariate analysis (Fisher or Mann-Whitney). Results: Overall, 268 consecutive patients were enrolled. Among them, 64 had IBD: one patient refused the switch and 63 [33 women, aged 34.5 (29–44), 42 CD, 21 UC] were included. At inclusion, duration of Remicade® therapy was 34.8 (14–74) months. Three infusions after the switch, 60 (95.2%) were still on Inflectra®. One patient stopped Inflectra® for pregnancy and 2 had IBD relapse: one was switched back to Remicade® and one to adalimumab. In July 2016, 8.4 (7.9–8.9) months after the switch, 2 more patients had stopped CT-P13 for suspected adverse event (purpura) while 55 (87.3%) remained treated with CT-P13. No allergic infusion reaction was reported. Changes from baseline were not significant: Mayo score (p=0.95), Harvey-Bradshaw (p=0.14), infliximab dose (p=0.71) and ITL [baseline (5.9±5 μg/mL); 3rd infusion (7.8±6μg/mL) (p=0.09)]. No patient developed anti-infliximab antibodies after the switch. Conclusions: This prospective observational study suggests that the switch from reference infliximab to CT-P13 does not change IBD evolution. After 3 infusions, 95.2% patients remained on CT-P13 treatment. No changes in clinical activity, infliximab doses and ITL were observed. No anti-infliximab antibodies appeared.