Treatment persistence and switching patterns of ABP 501 in European patients with inflammatory bowel disease

Approval of the adalimumab (ADA) biosimilar ABP 501 for inflammatory bowel disease (IBD) indications was based on the principle of extrapolation, without indication-specific clinical trial data. To evaluate the real-world treatment patterns of ABP 501 in patients with IBD. Retrospective analysis of pharmacy claims data from Germany and France. Continuously insured adult IBD patients who initiated ABP 501 between October 2018 and March 2020 were included. Treatment persistence, adherence, and post-ABP 501 switching patterns were evaluated for two mutually exclusive groups: ADA-naïve patients (i.e. no baseline use of ADA products) and ADA-experienced patients (i.e. previously treated with ADA products). A total of 3362 German patients and 733 French patients were included, with 54.4% and 65.3% being ADA-naïve patients, respectively. Median persistence (95% CI) on ABP 501 was 10.9 months (9.8-11.6) in ADA-naïve patients and 14.2 months (12.7-15.2) in ADA-experienced patients in Germany; for the French cohort, ADA-naïve and -experienced patients had median persistence of 12.8 months (10.2-14.7) and 11.5 months (8.8-14.4), respectively. During the first 12 months of ABP 501 initiation, 53.7% of German patients and 51.0% of French patients were adherent to the therapy. About 20% of patients in both countries switched from ABP 501 to another targeted therapy. In the German cohort, ADA-naïve patients most frequently switched to non-tumor necrosis factor inhibitor biologics, but ADA-experienced patients most commonly switched to reference product (RP); in the French cohort, patients most often switched to RP regardless of prior exposure to ADA products. About 50% of patients persisted on and were adherent to ABP 501 therapy during the first 12 months after treatment initiation in two large European countries. Post-ABP 501, switching patterns varied between countries, indicating diversified treatment practices warranting further research on reason(s) for switching and potential overall treatment outcomes.