Infliximab biosimilar-to-biosimilar switching in patients with inflammatory rheumatic disease: clinical outcomes in real-world patients from the DANBIO registry

ObjectiveSuccessful uptake of biosimilars in rheumatology is limited by lack of real-world evidence regarding effectiveness of biosimilar-to-biosimilar switching. We investigated infliximab biosimilars CT-P13-to-GP1111 switching among patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (AxSpA). MethodsObservational cohort study from the DANBIO registry. Patients were classified as originator-naive or originator-experienced. Retention rates of 1-year GP1111 treatment were explored (Kaplan-Meier). We identified baseline factors (at the time of switch) associated with withdrawal of GP1111 (multivariable Cox-regression analyses with HRs including originator treatment history). Changes in subjective and objective measures of disease activity 4 months before and after the switch were assessed in individual patients. ResultsOf 1605 patients (685 RA, 314 PsA and 606 AxSpA, median disease duration was 9 years, 37% in Clinical Disease Activity Index/Ankylosing Spondylitis Disease Activity Score remission), 1171 were originator-naive. Retention rates at 1-year were 83% (95% CI: 81% to 85%) and 92% (95% CI: 90% to 95%) for the originator-naive and originator-experienced, respectively. GP1111 retention rates were higher in originator-experienced compared to originator-naive with RA (HR=0.4 (95% CI: 0.2 to 0.7)) and PsA (HR=0.2 (95% CI: 0.1 to 0.8)), but not significantly for AxSpA: HR=0.6 (95% CI: 0.3 to 1.2). Lower disease activity was associated with higher retention. Changes in disease activity preswitch and postswitch were close to zero. ConclusionThis real-world observational study of more than 1600 patients with inflammatory arthritis showed high 1-year retention following a nationwide infliximab biosimilar-to-biosimilar switch. Retention was higher in originator-experienced and in patients with low disease activity, suggesting outcomes to be affected by patient-related rather than drug-related factors.

Automated summary

This study on biosimilar switching in rheumatology found that 1-year retention rate was high after switching to an infliximab biosimilar. Retention rates were higher in patients with previous experience with the originator drug and in patients with lower disease activity, indicating that outcomes are influenced by patient-related factors rather than drug-related factors.