One-Year Retention High With Infliximab Biosimilar Switching in Inflammatory Arthritis

One-year retention following infliximab biosimilar-to-biosimilar switching among patients with inflammatory arthritis was found to be high, according to results of a real-world observational cohort study presented at the American College of Rheumatology (ACR) Convergence 2022, held from November 10 to 14, in Philadelphia, Pennsylvania.

The researchers sought to explore the effectiveness of switching between the infliximab biosimilars CT-P13 and GP1111 among patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (axSpA), including those who had previously switched from the originator (ie, originator-experienced) to CT-P13, as well as those who were originator-naive.

The study included data from the DANBIO registry linked to national patient registries in Denmark to identify previous comorbidities. Patients with RA, PsA, and axSpA who underwent a biosimilar-to-biosimilar switch from CT-P13 to GP1111 between April 2019 and February 2020 were included in the study.

The main study outcomes in the 2 groups were 1-year GP1111 treatment retention and changes in disease activity 4 months prior vs 4 months after the biosimilar switch.

Clinical factors at the time of the switch associated with withdrawal, including treatment history with the originator biosimilar, were also included in the analysis.

A total of 1605 patients (685 with RA, 314 with PsA, and 606 with axSpA) had a median disease duration of 9 years. Overall, 37% of the participants were in remission, based on Clinical Disease Activity Index (CDAI)/Ankylosing Spondylitis Disease Activity Score (ASDAS). A total of 1171 of the participants were originator-naive switchers and 434 were originator-experienced switchers.

Results of the study showed that 1-year retention rates of GP1111 were 83% (95% CI, 81%-85%) and 92% (95% CI, 90%-95%) in the originator-naive and the originator-experienced group, respectively. At the 4-month preswitch and postswitch, changes in disease activity were nearly zero for all measures of disease activity (ie, Disease Activity Score in 28 joints [DAS28], ASDAS, and visual analog scale [VAS] pain).

Higher GP1111 retention rates were linked to being originator-experienced compared with originator-naive in patients with RA (hazard ratio [HR], 0.4; 95% CI, 0.2-0.7) and PsA (HR, 0.2; 95% CI, 0.1-0.8), but not axSpA (HR, 0.6; 95% CI, 0.3-1.2). Higher GP1111 retention rates were also associated with lower disease activity at baseline.

Overall, 1-year retention after the infliximab biosimilar-to-biosimilar switch was high.

The authors concluded, “Retention was higher in originator-experienced and in patients with low disease activity, suggesting outcomes [were] affected by patient- rather than drug-related factors.”

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.