The Childhood Arthritis & Rheumatology Research Alliance Start Time Optimization of Biologics in Polyarticular Juvenile Idiopathic Arthritis Study (STOP-JIA): A Comparative Effectiveness Study of CARRA Consensus Treatment Plans for Untreated Polyarticular JIA

Background: The optimal time to start biologics for polyarticular JIA (pJIA) remains uncertain. The Childhood Arthritis and Rheumatology Research Alliance (CARRA) developed 3 consensus treatment plans (CTPs) for untreated pJIA to compare strategies for starting biologics.

Methods: Start Time Optimization of biologics in PJIA (STOP-JIA) was a prospective, observational, CARRA Registry study comparing the effectiveness of: 1) Step Up (SU)- initial non-biologic disease modifying anti-rheumatic drug (DMARD) monotherapy, adding biologic if needed; 2) Early Combination (EC)- DMARD and biologic started together; 3) Biologic First (BF)- biologic monotherapy. The primary outcome was clinically inactive disease (CID) (Wallace) off glucocorticoids at 12 months. Secondary outcomes included PROMIS® pain interference and mobility, inactive disease defined by the clinical Juvenile Arthritis Disease Activity Score (cJADAS10 ID) and pediatric ACR70 (pACR70).

Results: Of 400 patients enrolled, 257 (64%) began SU, 100 (25%) EC and 43 (11%) BF. After propensity score weighting and multiple imputation, 37% of EC, 32% SU and 24% BF achieved ACR CID (p=0.17). cJADAS10 ID (score ≤2.5) also favored EC over SU (59% versus 43%; p=0.03) as did pACR70 results (80% versus 64%; p=0.008) but generalizability is limited by missing data. PROMIS® measures improved in all groups, but without significant differences. Seventeen serious adverse events were reported (mostly infections).

Conclusions: Achievement of CID off GC did not significantly differ between groups at 12 months. While there was a statistically significant higher likelihood of EC achieving cJADAS10 ID and pACR70, these results require further exploration.