Patient‐ReportedOutcomes Among Patients Ages Two to Seventeen Years With Polyarticular‐CourseJuvenile Idiopathic Arthritis Treated With Subcutaneous Abatacept: Two‐YearResults From an International Phase IIIStudy

To describe longitudinal changes in patient‐reported outcomes (PROs) in children with polyarticular‐course juvenile idiopathic arthritis (pJIA) treated with subcutaneous abatacept. Secondary analysis of a single‐arm, open‐label 24‐month study of patients ages 6–17 years and 2–5 years. PROs included Childhood Health Assessment Questionnaire‐Disability Index (CHAQ‐DI), parent global assessment of child well‐being (PaGA), pain assessment, and Activity Limitation Questionnaire (ALQ). Clinical outcomes included 50% or greater improvement in JIA American College of Rheumatology (ACR) criteria, clinically inactive disease, and Juvenile Arthritis Disease Activity Score. For the 6‐ to 17‐year‐old (n = 173) and 2‐ to 5‐year‐old (n = 46) cohorts, respectively, median (Q1, Q3) changes from baseline in CHAQ‐DI at months 4 and 24 were −0.3 (−0.8, 0.0) and −0.5 (−1.0, −0.1), and −0.4 (−0.8, 0.0) and −0.5 (−1.0–−0.1). Median pain scores were below cutoff threshold for clinically relevant pain (<35 mm) by month 1 (6 to 17 years, 32.3 mm; 2 to 5 years, 25.7 mm), reaching a nadir at month 24 (6 to 17 years, 6.0 mm; 2 to 5 years, 2.0 mm). For the 6‐ to 17‐year‐old and 2‐ to 5‐year‐old cohorts, respectively, median PaGA scores were 47.8 (n = 172) and 42.1 (n = 46) at baseline and 6.3 (n = 107) and 2.0 (n = 37) at month 24. In both cohorts, ALQ components improved from baseline to month 4 and were largely maintained to month 24. Clinical outcomes improved through to month 24. Early and sustained PRO improvements were reported in this phase III, open‐label trial of subcutaneous abatacept in patients with pJIA.