POS1292 REAL-WORLD EFFECTIVENESS OF ETANERCEPT AND ADALIMUMAB IN CHILDREN AND YOUNG PEOPLE WITH JUVENILE IDIOPATHIC ARTHRITIS (JIA) WITHOUT UVEITIS
Authors: L. Kearsley-Fleet, E. Baildam, M. Beresford, H. Foster, T. Southwood, W. Thomson, K. Hyrich
Journal: Annals of the Rheumatic Diseases (2021)

Background: Biologic therapies have revolutionised treatment pathways and outcomes for patients with juvenile idiopathic arthritis (JIA). Although there is a choice of approved TNF inhibitors available as a first biologic, there lacks data to inform treatment choices in clinical practice. Objectives: To compare short-term outcomes on etanercept and adalimumab in children and young people with JIA without uveitis, including drug survival, arthritis disease activity and function ability at 1 year. Methods: All patients starting a first biologic (etanercept/adalimumab including biosimilars) from 2010 in the UK JIA biologic registers (BCRD and BSPAR ETN) were included. Those with systemic JIA or with any history of uveitis were excluded. Data were collected at start of therapy, 6 months, 1 year, and then annually, including patient demographic, disease activity and drug therapy. In this analysis, drug survival and arthritis disease activity / function ability at 1 year (range 3-15 months) were investigated; comparing between therapies using logistic / linear regression, adjusted for propensity deciles. Results: There were 550 patients with outcome data available (to 30 Sept 2020); 384 etanercept, 166 adalimumab. At registration, 68% female, median age 12 years old (IQR 8-14), median disease duration 1 year (IQR 1-4), 72% on concomitant methotrexate. Disease activity was similar between both therapies at baseline and one year. At one year, 70% were still on biologic therapy; most stopping therapy for ineffectiveness (45%), adverse events (31%), or patient / family choice (15%). Inactive disease and minimal disease activity was achieved in 26% and 46% respectively, 48% achieved a minimally clinical important improvement in their functional ability (CHAQ improvement &gt;0.13). All Patients Adalimumab Etanercept N 550 166 384 Females 68% 59% 71% Age (years), median (IQR ) 12 (8-14) 12 (10-14) 11 (8-14) Disease duration (years), median (IQR ) 1 (1-4) 1 (0-3) 1 (1-4) ILAR Persistent oligo 9% 6% 11% Extended oligo 20% 14% 23% RF negative 37% 32% 39% RF positive 11% 11% 12% Psoriatic 5% 8% 4% Enthesitis-related 16% 27% 11% Undifferentiated 1% 2% 1% Concomitant oral steroids 16% 20% 15% Concomitant methotrexate 72% 84% 66% Follow-up time, years Median (IQR) 2.5 (1.4-3.8) 2.1 (1.2-3.1) 3.0 (1.6-4.0) Min-Max 0.4 - 8.2 0.4 - 7.3 0.4 - 8.2 Drug Survival Still on drug at one year 70% 67% 71% Still on drug at two years 47% 50% 46% CHAQ Baseline, mean (SE) 0.9 (0.04) 0.8 (0.06) 1.0 (0.04) One Year, mean (SE) 0.7 (0.03) 0.5 (0.06) 0.7 (0.04) Change, mean (SE) -0.2 (0.04) -0.2 (0.06) -0.2 (0.04) Regression coef (95% CI) - -0.09 (-0.2, 0.04) Ref PD Adjusted coef (95% CI) - -0.08 (-0.2, 0.07) Ref MCID (CHAQ ) Proportion achieved 48% 48% 48% OR (95% CI) - 1.0 (0.6, 1.5) Ref PD Adjusted OR (95% CI) - 1.2 (0.8, 1.9) Ref JADAS Baseline, mean (SE) 14 (0.4) 14 (0.7) 14 (0.4) One Year, mean (SE) 5 (0.3) 4 (0.5) 6 (0.3) Change, mean (SE) -9 (0.4) -9 (0.7) -8 (0.5) Regression coef (95% CI) - -1.1 (-2.3, -0.01)* Ref PD Adjusted coef (95% CI) - -1.0 (-2.8, 0.8) Ref Inactive Disease (JADAS&lt;1 ) Proportion achieved 26% 32% 24% OR (95% CI) - 1.5 (1.0, 2.4) Ref PD Adjusted OR (95% CI) - 1.5 (0.9, 2.4) Ref Minimal Disease Activity (MDA) [excludes enthesitis-related JIA] N=473 N=121 N=352 Proportion achieved 46% 49% 45% OR (95% CI) - 1.2 (0.8, 1.9) Ref PD Adjusted OR (95% CI) - 1.2 (0.8, 2.0) Ref Childhood Health Assessment Questionnaire (CHAQ), confidence interval (CI), International League Against Rheumatism (ILAR), interquartile range (IQR), odds ratio (OR), propensity decile (PD), rheumatoid factor (RF), standard error (SE). *p&lt;0.05 Conclusion: This is the first comparative effectiveness analysis of adalimumab and etanercept within UK children receiving TNFi therapies for JIA. Despite large patient numbers, there was no evidence of difference between adalimumab and etanercept regarding arthritis disease control or treatment persistence. For children without uveitis, both adalimumab and etanercept can be considered as effective treatment options for children and young people with JIA. Disclosure of Interests: None declared