FRI0190 Clinical outcomes from a nationwide non-medical switch from originator to biosimilar etanercept in patients with inflammatory arthritis after 5 months follow-up. results from the danbio registry

Abstract

Background: In Denmark, biological drugs are provided free by the hospitals to the patients via a tax-based system. In 2015 a non-medical switch from originator infliximab to CT-P13 was conducted (1). According to national guidelines in April 2016, a non-medical switch from originator (ETA, Enbrel 50 mg/week) to biosimilar etanercept (SB4, Benepali) was dictated when SB4 was marketed, including patients with inflammatory rheumatic diseases treated in routine care. Objective(s): To investigate 3 months' disease activity and 5 months' treatment withdrawal in ETA-treated patients (pts) with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthrits (SpA), who were switched to SB4 and monitored prospectively in the DANBIO registry. Method(s): Pts with RA/PsA/SpA followed in DANBIO since start of first bDMARD were included. Disease activity at 3 months before switch (pre-switch), at the switch and after 3 months (post-switch) and changes over time (DELTApre-switch and DELTApost-switch) were calculated. Disease flare was defined as DELTADAS28>=1.2 (RA/PsA) or DELTAASDAS>=1.3 (SpA). Factors associated with withdrawal (gender/ age/diagnosis/bDMARD-treatment-no/comedication methotrexate/baseline CRP/ patient's global score) were explored by multivariable Cox regression analysis. Result(s): In total, 1548 switch pts were identified (891 RA, 335 PsA, 322 SpA). 60% were women, age (median (IQR) 56 (44-65) yrs)). Prior ETA treatment duration was 5.2 (3.2-8.0) yrs. ETA was the first biological treatment in 49%, and the second in 33% of pts. Concomitant MTX was given in 60% (RA)/49% (PsA)/15% (SpA). Median follow-up time was 154 (110-178) days. Disease activity remained largely unchanged 3 months prior to vs. after the switch (Table). The proportion of patients with disease flare pre-/post switch was 8%/13% (RA), 9%/13% (PsA), 5%/5% (SpA). Overall, 129 pts (9%) stopped SB4 treatment during 5 months' follow-up (Table). Prior ETA treatment duration in these patients was 4.5 (2.7-7.1) years. Higher patient's global score (HR 1.12/cm, 95% CI (1.05-1.21), p=0.002) and no concomitant methotrexate (HR 2.28 (1.48-3.52), p<0.001) at baseline were associated with withdrawal. Conclusion(s): In 1548 patients with inflammatory rheumatic diseases treated with ETA for >5 years, disease activity was largely unaffected in the majority of patients 3 months after non-medical switch to SB4 and comparable to the fluctuations observed in the 3 months prior to the switch. Several patients (=9%) stopped treatment during 5 months follow-up. Higher patient's global score and no use of methotrexate were associated with withdrawal. Longer follow-up will offer additional understanding of the potential efficacy and safety consequences of the non-medical switch.