DOP73 Early biological use in a Belgian, prospective inception cohort of patients with Inflammatory Bowel Disease: the PANTHER cohort

Background The growing number of advanced therapies has revolutionized the management of inflammatory bowel disease (IBD). Although early use of biological therapies is associated with better long-term outcomes, no data exist for the Belgian population. To this end, we evaluated treatment patterns in biological use and persistence in a Belgian inception cohort. Methods The PANTHER (Prognostic biobANk of paTients witH Early cRohn’s or colitis) cohort consists of adult IBD patients recruited in 3 Belgian IBD referral centres. Patients are included within 3 months after diagnosis and are naïve for immunosuppressives and biologicals, and without previous IBD-related surgery. Treatment use and outcomes are prospectively collected, and time trends for biological use were analysed using log-rank tests and Cox regression (R 4.3.2). Results Between 2015 and 2023, a total of 473 newly-diagnosed IBD patients were recruited (270 Crohn’s disease (CD) [57%]; 199 ulcerative colitis (UC) [42%]; 4 [1%] IBD type unclassified) (Table 1). During a median (IQR) follow-up of 2.6 (1.3-4.3) years, 64 patients (14%) required surgery (n=10 colectomy; n=54 ileocecal/small bowel resection); and 250 patients (53%) received biological therapy within the 1st year after diagnosis. Most patients were treated with anti-TNF (CD 67%; UC 55%) as first-line biological, followed by anti-integrins (CD 24%; UC 43%) and anti-IL12/23 (CD 9%; UC 2%). Time series analysis showed a significant increase in biological use within the 1st year after diagnosis when comparing patients diagnosed between 2015-2017 (44%) to those between 2018-2020 (57%), and to 2021-2023 (66%) (p=0.03) (Fig. 1A). Factors associated to this early biological use were younger age (HR=0.99 [95%CI: 0.98-0.99]), a diagnosis of CD (HR=2.2 [95%CI: 1.6-2.8]); and perianal disease in CD (HR=2.8 [95%CI: 1.8-12.8]). Within this early biological exposure group, 26 patients (10%) needed a resection later on. Therapy persistence over time was higher with early exposure rates in patients diagnosed in 2021-2023 (82%) and 2018-2021 (71%), as compared to 2015-2017 (63%) (p=0.08) (Fig.1B). The mode-of-action of first-line biological did not show any association with persistence (HR=1.0 [95%CI: 0.4-3.0]). Overall, only 26% of patients had to switch to a second-line, with a switch [anti-TNF >anti-IL12/23] being the most frequent in CD (50%); and from [anti-TNF >anti-integrins] (46%) or vice versa (40%) in UC. Conclusion In this Belgian inception cohort, two thirds of patients are currently initiated with biological therapy within the first year after diagnosis. This increased biological use is associated with high therapy persistence rates of >80% after a median follow-up of 1.5 years, and with low rates of surgical resections.