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

Background 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 ( switchers). Pts treated with 25 mg ETA or 50 mg powder solution were not mandated to switch ( non-switchers). Objectives To characterise switchers and non-switchers , and to compare 1 year treatment retention in switchers with non-switchers and a historic cohort of ETA treated pts. Methods 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. Results 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%( 72–82 in non-switchers and 90%( 88–92 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 Conclusions Of >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. Acknowledgements Partly sponsered by Biogen Disclosure of Interest B. Glintborg Grant/research support from: Abbvie, Biogen, Pfizer, I. Sorensen: 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. Grydehoj: None declared, N. Krogh: None declared, M. Hetland Grant/research support from: Abbvie, Biogen, BMS, CellTrion, MSD, Novartis, Orion, Pfizer, Samsung, UCB