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

Background: 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.

Objectives: To evaluate the real-world treatment patterns of ABP 501 in patients with IBD.

Design: Retrospective analysis of pharmacy claims data from Germany and France.

Methods: 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).

Results: 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.

Conclusion: 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.