THU0189 One-year treatment retention after a nationwide non-medical switch from originator to biosimilar etanercept in 2,061 patients with inflammatory arthritis followed in the danbio registry
Authors: B. Glintborg, I.J. Sørensen, E. Omerovic, F. Mehnert, N. Manilo, K. Danebod, D.V. Jensen, H. Nordin, A.G. Loft, O. Hendricks, S. Chrysidis, B.L. Andersen, J.L. Raun, H. Lindegaard, J. Espesen, S.H. Jakobsen, I.M.J. Hansen, E.B. Dalsgaard, D.D. Pedersen, S. Kristensen, A. Linauskas, L.S. Andersen, J. Grydehøj, N. Krogh, M.L. Hetland
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> In Denmark, rheumatoid arthritis(RA), psoriatic arthritis(PsA) and axial spondyloarthritis(AxSpA) patients (pts) treated with originator etanercept (ETA) 50 mg SC conducted a mandatory non-medical switch to biosimilar Etanercept (SB4) in April 2016 (<i>switchers).</i> Pts treated with 25 mg ETA or 50 mg powder solution were not mandated to switch (<i>non-switchers).</i> <h3>Objectives</h3> To characterise switchers and non-switchers<i>,</i> and to compare 1 year treatment retention in switchers with non-switchers and a historic cohort of ETA treated pts. <h3>Methods</h3> Pt data were retrieved from the DANBIO registry and national registries. We applied Chi-square/Mann-Whitney for comparisons and Kaplan-Meier/Cox regression analyses (crude, adjusted for gender/age/MTX/remission/comorbidities/ETA-start-year) for drug retention. The historic cohort encompassed pts treated with ETA by Jan 1st 2015. <h3>Results</h3> Of 2,061 ETA treated pts by April 2016, 79% switched to SB4 (933RA/351PsA/337AxSpA), whereas 21% (286RA/56PsA/98AxSpA) continued ETA. In RA, compared to switchers, non-switchers more often received 25 mg ETA, had higher disease activity and HAQ (table 1). Similar patterns were seen for PsA and AxSpA. Median(IQR) follow-up was 383(314–414)days. In all 3 cohorts, withdrawals were mainly due to lack of effect. Retention rate was lowest in non-switchers (figure 1). 1 year adjusted rates were 83% (95% CI 79–87) in switchers, 77%(<sup>72–82</sup> in non-switchers and 90%(<sup>88–92</sup> in historic cohort. Pts not in remission had poorer retention than pts in remission both in switchers (hazard ratio 1.7 (1.3–2.2) and non-switchers (2.4 (1.7–3.6)). Numbers are medians (IQR) unless otherwise stated. * DAS28 &lt;2.6 (RA, PsA), ASDAS &lt;1.3 (AxSpA) <h3>Conclusions</h3> Of &gt;2000 ETA treated pts, ≈80% switched to SB4. Non-switchers had higher disease activity and more often received 25 mg ETA. Switchers had poorer retention rate than a historic ETA-cohort, but better than non-switchers. Withdrawal was most common in pts not in remission. These real-world data indicate that a switching-to-biosimilar option facilitated clinical decision making in standard care, leading to withdrawal from ineffective therapy in both switchers and non-switchers. <h3>Acknowledgements</h3> Partly sponsered by Biogen <h3>Disclosure of Interest</h3> B. Glintborg Grant/research support from: Abbvie, Biogen, Pfizer, I. Sørensen: None declared, E. Omerovic: None declared, F. Mehnert: None declared, N. Manilo: None declared, K. Danebod: None declared, D. Jensen: None declared, H. Nordin: None declared, A. G. Loft Grant/research support from: AbbVie, MSD, Novartis, Pfizer, Roche, UCB, O. Hendricks Grant/research support from:: Abbvie, Roche, Novartis, S. Chrysidis: None declared, B. Andersen: None declared, J. Raun: None declared, H. Lindegaard: None declared, J. Espesen: None declared, S. Jakobsen: None declared, I. M. Hansen Grant/research support from: Roche, E. Dalsgaard: None declared, D. Pedersen: None declared, S. Kristensen: None declared, A. Linauskas: None declared, L. Andersen: None declared, J. Grydehøj: None declared, N. Krogh: None declared, M. Hetland Grant/research support from: Abbvie, Biogen, BMS, CellTrion, MSD, Novartis, Orion, Pfizer, Samsung, UCB