Three-Year Outcomes and Latent Class Trajectory Analysis of the Childhood Arthritis and Rheumatology Research Alliance Polyarticular JIA Consensus Treatment Plans Study

Objective: To assess the impact of differences in the timing of initial biologic disease-modifying antirheumatic drug (bDMARD) therapy using the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Start Time Optimization of biologics in Polyarticular Juvenile Idiopathic Arthritis (JIA) (STOP-JIA) – consensus treatment plans study on outcomes through three years. Methods: Start Time Optimization of biologics in Polyarticular-JIA participants with CARRA Registry follow-up through three years were eligible. Outcomes included American College of Rheumatology clinically inactive disease (CID) off glucocorticoids, clinical Juvenile Arthritis Disease Activity Score based on 10 joints inactive disease (cJADAS-10-ID) (cJADAS-10-ID: cJADAS-10 ≤ 2.5), clinical remission on medication (CRM), and proportion of time in CID and/or cJADAS-10-ID. Latent class trajectory modeling (LCTM) was applied to identify participant subgroups sharing similar disease courses over this period. Results: A total of 297 participants were included (n = 190 step-up [SU], 76 early combination [EC], and 31 biologic first). At the three-year visit, CID was achieved by 35%, 42%, and 44%, respectively (P = 0.35 for SU versus EC). EC was superior to SU in achieving CRM (59.9% vs 40.6%; P = 0.012), time spent in CID (38% versus 30%; P = 0.04), and cJADAS-10-ID (51% versus 41%; P = 0.02). Slow, moderate, and rapid improvement trajectories were identified by LCTM; bDMARD initiation within the first (odds ratio [OR] 5.33) or second (OR 2.67) month from baseline was associated with the rapid improvement trajectory. Conclusion: EC was superior to SU across three years for outcomes reflecting time spent in lower disease activity. Starting bDMARD within two months predicted rapid improvement and maintenance of inactive disease. These results support the hypothesis that early bDMARD initiation reduces overall disease burden in pJIA.