Physician-Led Switching From Reference Biologics to Biosimilars: What is the Effect on Selected Health-Related...

Biologics have broadened the therapeutic options for many diseases, but their high costs have raised concerns about long-term affordability for patients and health systems. A potential cost-containment strategy is physician-led switching from originator (ie, reference) biologics to biosimilars. We assessed the effect of this form of switching on selected health-related outcomes and costs in patients with inflammatory bowel disease.

We analyzed German claims data from 2014 to 2022 for patients with inflammatory bowel disease (ICD K50, K51, and K52.3) who received infliximab (ATC L04AB02) or adalimumab (ATC L04AB04) during the observation period. Patients who did not switch to a biosimilar were reweighed to resemble those who did. We then estimated the effect of switching for a follow-up period of up to 4 years using difference-in-differences regression. Additionally, we analyzed treatment persistence using a 2-period difference-in-differences regression.

We identified 3464 patients who met our inclusion criteria, including 914 who switched from an originator biologic to a biosimilar (infliximab: 445; adalimumab: 469). Although most health-related outcomes appeared unaffected by the switch, we observed significantly higher treatment persistence among patients who switched to a biosimilar compared with those who continued treatment with the originator biologic. The switch reduced costs by lowering pharmaceutical spending, with significant reductions observed during the first 2 years.

Our results indicate that physician-led switching from originator biologics to biosimilars does not lead to worse health-related outcomes and results in lower costs. Thus, it appears to be an effective cost-containment strategy in the management of inflammatory bowel disease.