Effectiveness and safety of a biosimilar-to-biosimilar switch of the TNF inhibitor etanercept in patients with chronic inflammatory rheumatic diseases.

Background: Biosimilar disease-modifying anti-rheumatic drugs (bsDMARDs) has created a financial incentive to encourage switching to cheaper products.

Objectives: We aim to study the effectiveness and safety of a non-medical bsDMARD-to-bsDMARD switch from originator etanercept (ETN) to bsDMARD ETN (SB4) and successive to another bsDMARD ETN (GP2015) in patients with chronic inflammatory rheumatic diseases in a real-life setting.

Methods: Retrospective chart review of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) or axial spondyloarthritis (axSpA) who had been treated with originator ETN and were switched twice to ETN bsDMARD for non-medical reasons thereafter. All patients received ETN 50 mg/week. Disease activity and physical function was assessed every 12 weeks with standardized questionnaires.

Results: A total of 100 patients who switched twice [54 RA, 27 axSpA, 19 PsA, mean age 54.3 (15.1), 46% male] were included. Patients with axSpA were younger than RA and PsA patients. Patients with SpA were less likely to receive conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) than RA patients. Duration of treatment with originator ETN before the first switch was 3.3 (2.3) years. Retention rate 6 months after the second ETN bsDMARD switch was 89%. Disease activity and physical function scores remained rather unchanged in patients with RA and axSpA longitudinally, while there was some more fluctuation in PsA patients. Six patients lost efficacy and were switched back to originator ETN in month 6 (n = 4) or to another mode of action (n = 2). There were 14 adverse events (AE) reported in eight patients. One patient re-administered bsDMARD GP2015 successfully 3 months after healing of mucosal erosions.

Conclusion: No relevant change in disease activity and physical function were observed in a non-medical bsDMARD-to-bsDMARD switch scenario. The retention rate after switches from originator ETN to two ETN bsDMARD was close to 90%. Multiple switches resulted in a high adherence rate without clinically important efficacy or safety signals.