Outcomes following switching from originator to biosimilar product in children and young people with jia

Abstract Background/Aims There are many biosimilar products available to use in children and young people with JIA. Due to competitive pricing, patients are being switched from biologic originator to biosimilar (non-medical switch). This analysis aims to describe characteristics of, and outcomes, following TNF-inhibitor originator to biosimilar switch in JIA. Methods All patients in the UK JIA Biologics Register switching from an originator to a biosimilar of the same product were identified. Patient characteristics are presented, including time on originator prior to switch. Patients were followed until their final follow-up form was returned. For those with >1 year of follow-up post-switch, treatment persistence and reasons for stopping are described. Results As of 28-Sept-2022, 202 children and young people had switched from originator to biosimilar; 125 adalimumab, 55 etanercept, and 22 infliximab (table). Switching was seen in all ILAR categories. Patients were predominantly female (63%), median age at JIA diagnosis six years, 11 years at originator start, 14 years at biosimilar start, median time on originator 2.2 years. Most patients had started originator as their first biologic (74%) and most started biosimilar with no significant treatment gaps. Five patients reported >1 year gap between originator stop and biosimilar start, suggesting a planned period off biologic therapy (two stopped for remission, one for adverse event, two unknown). Of the 134 patients with >1 year of follow-up available after switching (median 1.9 years per patient), 77 remained on biosimilar at their final follow-up, whilst 57 had stopped therapy. Of those who stopped, 10 had stopped for remission, 12 stopped for ineffectiveness, 18 for adverse event, and 17 other/missing reason. Thirty-nine patients then re-started biologic therapy (including four of the remission patients); 16 switched back to the originator mostly due to an adverse event on the biosimilar, and 23 started a different biologic therapy mostly due to inefficacy of the biosimilar. Conclusion Many children with JIA have now been switched from TNF-inhibitor originator to biosimilar product, with the majority still receiving their biosimilar after one year. Switching back to originator was uncommon, 12% overall after one year, suggesting good tolerance of non-medical switching in this patient population. Disclosure L. Kearsley-Fleet: None. E. Baildam: None. M.W. Beresford: None. S. Douglas: None. H.E. Foster: None. T.R. Southwood: None. K.L. Hyrich: Member of speakers’ bureau; non-personal speakers fees from Abbvie. Grants/research support; BMS, UCB, Pfizer.