Effectiveness of biosimilar infliximab CT-P13 compared to originator infliximab in biological-naïve patients with rheumatoid arthritis and axial spondyloarthritis: data from the Portuguese Register.

OBJECTIVES: To compare the effectiveness of the infliximab biosimilar CT-P13 with originator infliximab over 24 months of follow-up in biological-naïve patients with rheumatoid arthritis (RA) and axial spondyloarthritis (axSpA). METHODS: Biological-naïve patients from the Rheumatic Diseases Portuguese Register (Reuma.pt), with a clinical diagnosis of RA or axSpA, who were starting either the infliximab biosimilar CT-P13 or the originator infliximab after 2014 (date of market entry of CT-P13 in Portugal), were included. Patients on biosimilar and originator were compared regarding different response outcomes at 3 and 6 months, adjusting for age, sex and baseline C-reactive protein (CRP). The main outcome was the change in DAS28-erytrocyte sedimentation rate (ESR) for RA and the ASDAS-CRP for axSpA. Additionally, the effect of infliximab biosimilar vs originator on different response outcomes over 24 months of follow-up was tested with longitudinal generalized estimating equations (GEE) models. RESULTS: In total, 140 patients were included, 66 (47%) of which with RA. The distribution of patients starting the infliximab biosimilar and the originator was the same between the two diseases (approximately 60% and 40%, respectively). From the 66 patients with RA, 82% were females, mean age was 56 years (SD 11) and mean DAS28-ESR 4.9 (1.3) at baseline. As for the patients with axSpA, 53% were males, mean age was 46 years (13) and mean ASDAS-CRP 3.7 (0.9) at baseline. There were no differences in efficacy between RA patients treated with the infliximab biosimilar and the originator, either at 3 months (∆DAS28-ESR: -0.6 (95% CI -1.3; 0.1) vs -1.2 (-2.0; -0.4)), or at 6 months (∆DAS28-ESR: -0.7 (-1.5; 0.0) vs -1.5 (-2.4; -0.7)). This was also true for patients with axSpA (∆ASDAS-CRP at 3 months: -1.6 (-2.0; -1.1) vs -1.4 (-1.8; -0.9) and at 6 months: -1.5 (-2.0; -1.1) vs -1.1 (-1.5; -0.7)). Results were similar with the longitudinal models over 24 months. CONCLUSION: There are no differences in effectiveness between the infliximab biosimilar CT-P13 and the infliximab originator in the treatment of biological-naïve patients with active RA and axSpA in clinical practice.

Biosimilars in rheumatology.

Biotechnologicals are an invaluable resource in the treatment of patients with inflammatory rheumatic diseases (IRD) non-responsive or intolerant to conventional therapies. However, they are the main driver for increase in direct costs and represent a significant economic burden to healthcare systems worldwide. Since biosimilars are similar and more affordable versions of previously licenced biotechnologicals, they are expected to contribute to healthcare system sustainability and reduce inequities in treatment access. The landmark approval of CT-P13 as the first infliximab biosimilar paved the way for new infliximab but also etanercept, adalimumab and rituximab biosimilars. In Europe, North America and some countries of Asia, development is strictly regulated and only those presenting a totality-of-evidence dossier with highly similar physicochemical, biological and clinical performances are endorsed by regulatory agencies as biosimilars. The current article addresses the importance of biosimilar medicines in the treatment of IRD, as well as their innovative development and regulatory pathways, clinical evidence of similarity and challenges that may undermine their widespread use and success.