Ten-year safety and clinical benefit from open-label etanercept treatment in children and young adults with juvenile idiopathic arthritis

Abstract Objectives CLIPPER2 was an 8-year, open-label extension of the phase 3b, 2-year CLIPPER study on the safety and efficacy of etanercept in patients with JIA, categorized as extended oligoarticular arthritis (eoJIA), enthesitis-related arthritis (ERA) or PsA. Methods Participants with eoJIA (2–17 years old), ERA or PsA (each 12–17 years old) who received ≥1 etanercept dose (0.8 mg/kg weekly; maximum 50 mg) in CLIPPER could enter CLIPPER2. Primary end point was occurrence of malignancy. Efficacy assessments included proportions achieving JIA ACR 30/50/70/90/100 criteria and ACR inactive disease criteria, and clinical remission (ACR criteria) or Juvenile Arthritis DAS (JADAS) ≤1. Results Overall, 109/127 (86%) CLIPPER participants entered CLIPPER2 [n = 55 eoJIA, n = 31 ERA, n = 23 PsA; 99 (78%) on active treatment]; 84 (66%) completed 120 months’ follow-up [32 (25%) on active treatment]. One malignancy (Hodgkin’s disease in 18-year-old patient with eoJIA treated with methotrexate for 8 years) was reported; there were no cases of active tuberculosis or deaths. Numbers and incidence rates (events per 100 patient-years) of TEAEs (excluding infections/ISRs) decreased from 193 (173.81) in Year 1 to 9 (27.15) in Year 10; TE infections and serious infections also decreased. Over 45% of participants (n = 127) achieved JIA ACR50 responses from Month 2 onwards; 42 (33%) and 34 (27%) participants achieved JADAS and ACR clinical remission, respectively. Conclusions Etanercept treatment up to 10 years was well tolerated, consistent with the known safety profile, with durable response in the participants still on active treatment. The benefit–risk assessment of etanercept in these JIA categories remains favourable. Trial registration ClinicalTrials.gov IDs: CLIPPER (NCT00962741); CLIPPER2 (NCT01421069)