P0879Adverse events and infection risk in Inflammatory Bowel Disease after initiating biosimilars/originator infliximab

Abstract Background This study aimed to describe the occurrence of adverse events (AEs) among individuals with inflammatory bowel disease (IBD) treated with infliximab (IFX) and to compare the risk of infection between those receiving biosimilar (IFX-B) versus originator (IFX-O). Methods Prospective and retrospective data on individuals with Crohn’s disease (CD) or ulcerative colitis (UC) who initiated IFX-B or IFX-O between 2018 and 2024 were obtained from seven IBD clinical centres contributing to CAN-AIM’s pan-Canadian clinical registry of biosimilar/bio-originator users. Participants were followed from IFX initiation until death, or last visit before discontinuation/switching, whichever came first. AEs occurring during infliximab treatment were summarized by affected organ system and severity (mild, moderate, or severe, as assessed by the treating physician). Incidence rates (IRs) of infection (per 100 person-years PY, with 95% confidence intervals CI) were estimated, comparing IFX-B versus IFX-O. Multivariate hazard regression assessed time to first infection, comparing IFX-B versus IFX-O. The model was adjusted for sex, age, IBD type (CD or UC), IBD duration, prior/current corticosteroid use, and prior use of other biologics. Results A total of 208 individuals (117 CD, 91 UC) were included; 49% were female, and the mean age at infliximab initiation was 40 years. Most (75%) were biologic-naïve, and 58% started on IFX-B (Table 1). Overall, 232 AEs were reported among 108 individuals, most frequently infections (28%), gastrointestinal disorders (including nausea and abdominal pain, with 9%), and skin/subcutaneous tissue disorders (including rash and local skin reaction, with 17%). Approximately 10% of AEs were classified as severe. Over a median follow-up of 1.7 years (interquartile range 0.6–4.0), 33 individuals experienced a first infection, corresponding to an overall IR of 5.3 events/100 PY (95% CI 3.8–7.4). The IR was 10.6 (95% CI 6.7–16.9) among IFX-B users and 3.3 (95% CI 2.0–5.5) among IFX-O users. No significant difference in the adjusted hazard ratios (aHRs) were observed when comparing IFX-B versus IFX-O (aHR 1.84 (95% CI 0.74-4.55). Conclusion In this multicentre Canadian cohort of IBD patients treated with infliximab, infections were the most frequently reported adverse events. Despite numerically higher crude infection rates among IFX-B users, adjusted analyses were unable to demonstrate a significant difference in the risk of infection between infliximab biosimilar and originator users. Conflict of interest: Moura, Cristiano S: No conflicts Berger, Claudie: I have no conflict of interest. Lukusa, Luck: N/A Singh, Harminder: Harminder Singh has been on advisory boards or consulted for Pendopharm, Amgen Canada, Abbvie Canada, Pfizer Canada, Organon Canada, Takeda Canada, Innomar Strategies, Eli Lily Canada and Guardant Health, Inc consulted for the Canadian Agency for Drugs and Technology in Health has received research funding for an investigator-initiated study from Pfizer and holds shares of VasCon. recieved educational grants from Pfizer Canada, Organon Canada in kind research funding from Pendopharm Narula, Neeraj: Grant: Takeda, Pfizer, Abbvie Personal Fees: Abbvie, Janssen, Takeda, Pfizer, Merck, Amgen, Sandoz, Iterative Health, Innomar Strategies, Fresinius Kabi, Viatris, Celltrion, Organon, Eli Lilly, Ferring Non-financial Support: Abbvie, Janssen, Takeda, Pfizer, Ferring Targownik, Laura: Dr. Targownik reports personal fees and non-financial support from Abbvie Canada, personal fees and non-financial support from Johnson+Johnson Innovative Medicine, personal fees from Takeda Canada, personal fees from Amgen Canada, personal fees from Merck Canada, personal fees from Organon Canada, personal fees from Pfizer Canada, personal fees from Lilly Canada, personal fees from Bristol Myers Squibb Canada, outside the submitted work . Leung, Yvette: Dr. Leung reports personal fees and other from cellltrion, personal fees from abbvie, personal fees from janssen, personal fees from eli lilly, personal fees from takeda, non-financial support from takeda, non-financial support from pfizer, personal fees from pfizer, outside the submitted work . Zezos, Petros: None Polewiczowska-Nowak, Beata: Nothing to disclose. Baumgart, Daniel C.: Past 12 Months. Scientific Advisory Boards: AbbVie, Alfasigma, Eli Lilly Fresenius Johnson & Johnson Pfizer Roche Takeda. Travel Support: Afa Sigma, AbbVie, Eli Lilly, Johnson & Johnson Pfizer, Takeda. Education or Research Grants: AbbVie, Alfasigma, Amgen, AstraZeneca, Boston Scientific, Biogen, Canon Medical Systems, Celltrion, Dr. Falk, Ferring, Fresenius Kabi, Gilead Sciences, Ipsen, Janssen-Cilag GmbH (Johnson & Johnson), Lilly. Nestlé Health Science, Pfizer. Afif, Waqqas: Grant: Abbvie, Takeda, Pfizer, Janssen Personal Fees: Advisory Boards: Abbvie, Amgen, BMS, Eupraxia, Eli-Lilly, GSK, Janssen, Innomar, Merck, Pfizer, Sandoz, Sanofi, Takeda Dr. Bernatsky, Sasha: No conflict of interest