Ab1127 the retention rate of etanercept and adalimumab in first-line and after non-medical switch in patients with psoriatic arthritis: a comparison between originators and biosimilars. a single-center retrospective study.

Background Psoriatic arthritis is a chronic immune-mediated disease that may appear with arthritis and/or enthesitis and systemic manifestations, affecting 0.1-1% of the general population and up to 30% of patients with psoriasis. A greater understanding of the pathogenesis has led to an increase of therapeutic options, namely biotechnological drugs which may prevent the progression of the disease and improve the quality of life by acting on specific pathways. Among these drugs, anti-TNFα agents play an important role. Adalimumab (ADA) and Etanecept (ETA) were the first developed ones, indeed they are defined as “originator” drugs. Subsequently, “biosimilars” have been developed. They are defined by the EMA as highly similar to other biological agents already on the market in terms of qualitative characteristics, biological activity, safety, and efficacy. Spending review and pharmaco-economic policies have almost “imposed” the use of non-medical switching (NMS). Objectives The aim of this study is to evaluate the retention rate of ETA and ADA originators, compared to their biosimilar counterparts, in the first line and after NMS, detecting discontinuation for adverse events (AEs) or ineffectiveness, in patients with psoriatic arthritis. Methods Fifty-four patients diagnosed with psoriatic arthritis were enrolled (F: 61%; mean age 53.4±13 years, BMI 24.9±3.6), Baseline disease activity was 4, 1 ± 1.1. Inclusion criteria were age >18 years, fulfillment of CASPAR 2006 criteria for PsA, therapy with originators or biosimilar etanercept or adalimumab in the first line, with the possibility of no NMS, stable combined therapy with methotrexate during the observation time. Statistical significance was set at p⩽0.05. Results The retention rate of ETA and ADA originators was 541 ± 70 weeks and 486 ± 24 weeks, respectively. The retention rates of biosimilar ETA and biosimilar ADA in the first line were 265 ± 20 weeks and 79 ± 21 weeks, respectively (p=0.231). After NMS, the retention rate of biosimilar ETA and biosimilar ADA was 49.1 ± 13 weeks and 108 ± 12 weeks, respectively. Discontinuation due to AEs were recorded in 8.3% of patients receiving originator ETA, 5% of patients receiving originator ADA, and 31% of patients receiving biosimilar ADA. Discontinuation due to ineffectiveness occurred in 54% of patients treated with originator ETA, in 40% of patients treated with originator ADA, and in 44% of patients treated with biosimilar ADA. In patients treated with biosimilar ETA, no suspensions were recorded either for AEs or for ineffectiveness. Conclusion Our data show that the retention rate of originator drugs was higher than that of biosimilars, both when administered in the first line and after a NMS. A greater number of suspensions were recorded for AEs and, to a lesser extent, for ineffectiveness with biosimilar ADA compared to originator ADA, while in patients treated with biosimilar ETA no suspensions were recorded either for AEs or for ineffectiveness. References [1]Gossec L, Baraliakos X, Kerschbaumer A, et al. EULAR recommendations for the management of psoriatic arthritis with pharmacological therapies: 2019 update. Ann Rheum Dis. 2020;79(6):700-712. doi:10.1136/annrheumdis-2020-217159; [2]Veale DJ, Fearon U. The pathogenesis of psoriatic arthritis. Lancet. 2018;391(10136):2273-2284. doi:10.1016/S0140-6736(18)30830-4; [3]Taylor W, Gladman D, Helliwell P, et al. Classification criteria for psoriatic arthritis: development of new criteria from a large international study. Arthritis Rheum. 2006;54(8):2665-2673. doi:10.1002/art.21972 [4]Ogdie A, Coates LC, Gladman DD. Treatment guidelines in psoriatic arthritis. Rheumatology (Oxford). 2020;59(Suppl 1):i37-i46. doi:10.1093/rheumatology/kez383; [5]Gherghescu I, Delgado-Charro MB. The Biosimilar Landscape: An Overview of Regulatory Approvals by the EMA and FDA. Pharmaceutics. 2020;13(1):48. Published 2020 Dec 31. doi:10.3390/pharmaceutics13010048 Acknowledgements: NIL. Disclosure of Interests None Declared.