(SLA-038) Single and multiple switches, swap and retransitioning among 28,073 biological drug users with inflammatory bowel disease: results from Italian VALORE distributed database network

Background: Considering the large number of biological drugs (both originator and biosimilars) that have been approved for the treatment of inflammatory bowel diseases (IBDs) such as Crohn’s disease (CD) and ulcerative colitis (UC), the switching patterns of biological drugs in IBD patients in the real-world setting might be very complex.

Objectives: To describe the switching pattern of biological drugs (originators and biosimilars) in IBD patients in Italy in the last decade.

Methods: A retrospective cohort study was conducted using the VALORE distributed database network, which is based on administrative data from 14 Italian regions. Patients with at least 1 year of look-back and 1 year of follow-up were selected. First-ever users of biological drugs with ≥2 dispensing in the period 2010-2023 and with IBD as an indication for use were included. The frequency of switches and swaps (i.e. switches between different classes of biological drugs), multiple switches (≥ 2 switch or swap), and switch-back (from biologic drug A to B and then back to A) within 1,3 and 5 years from treatment start were described. For patients who switched from an originator to a biosimilar of the same active ingredient, the proportion of patients who switched back to the originator (i.e., retransitioning) was calculated. Multivariate COX regression analysis was conducted to search for predictors of multiple switches at three years of follow-up.

Results: A total of 28,073 first-ever users of biological drugs for IBDs (55.8% with CD; 44.2% with UC) were identified in the study period: most patients started biological treatment with adalimumab (12,725 - 45.3%), and infliximab (11,119 - 39.6%). The F/M ratio was 0.79, with a median age of 41.0 years (IQR: 27.0-54.0). The cumulative frequency of patients with at least one switch/swap was 12.0%, 35.6%, and 52.6% at 1, 3, and 5 years of follow-up, while those who switched at least twice were 9.9% and 18.7% at 3 and 5 years, respectively. Retransitioning from biosimilar to originator occurred in 10% of patients. Patients starting with anti-TNF-α were likely to switch/swap more rapidly and more frequently, irrespective of the timeframe, than those starting with ustekinumab or vedolizumab. Depression and corticosteroid use were identified as predictors of multiple switches at three years of follow-up.

Conclusions: About half of first-ever users of biological drugs with IBDs switched or swapped within five years from treatment start. Anti-TNF-α drugs were more likely and more rapidly to switch/swap than vedolizumab and ustekinumab. Notably, 1 out of 5 had changed biologic therapy more than once at five years. Among those who switched to a biosimilar, 1 out of 10 retransitioned to the originator.