POS1293 TEN-YEAR EFFICACY DATA FROM THE CLIPPER STUDIES: OPEN-LABEL, LONG-TERM ETANERCEPT TREATMENT IN CHILDREN AND YOUNG ADULTS WITH EXTENDED OLIGOARTICULAR, ENTHESITIS-RELATED, OR PSORIATIC JUVENILE IDIOPATHIC ARTHRITIS

Abstract

Background: CLIPPER2 was an 8-year, open-label extension of the phase 3b, 2-year CLIPPER study of the safety and efficacy of etanercept (ETN) in patients (pts) with juvenile idiopathic arthritis (JIA), categorized as extended oligoarticular JIA (eoJIA), enthesitis-related arthritis (ERA), or psoriatic arthritis (PsA). Objectives: Evaluation of the efficacy of ETN and its effect on health outcomes over 10 years of follow-up were secondary objectives and are reported here. Methods: Pts (n=127) with eoJIA (n=60; 2-17 years of age), ERA (n=38; 12-17), or PsA (n=29; 12-17) who received ≥1 ETN dose (0.8 mg/kg once weekly [max, 50 mg]) in CLIPPER were eligible to enter CLIPPER2. The study design has been reported previously.1 Efficacy endpoints included proportions of pts achieving JIA American College of Rheumatology (ACR) 30/50/70/90/100 criteria, Juvenile Arthritis Disease Activity Score (JADAS) inactive disease and clinical remission criteria, and sustained clinical remission (ACR criteria) or JADAS ≤1 for 12 continuous months (mths). Exploratory efficacy endpoints included time to fare following ETN withdrawal (based on ≥30% worsening in ≥3/6 ACR Pedi components, with ≥30% improvement in <2/6 remaining components and ≥2 active joints), and time to re-treatment with ETN. Observed Cases were used (I.e., there was no imputation for missing data) for pts who were in the Active Treatment Period. Results: A total of 109/127 (86%) CLIPPER participants entered CLIPPER2 (n=55 eoJIA, n=31 ERA, n=23 PsA), with 99 (78%) pts continuing in the Active Treatment Period. Overall, 84 (66%) pts completed 120 mths of follow-up; 27 (21%) while actively taking ETN. Thirty (24%) pts entered the Withdrawal Period from the Active Treatment Period (I.e., they discontinued ETN, either by meeting the Wallace defnition for clinically inactive disease for at least 6 months on ETN, or by having had a good clinical response and being deemed to beneft from withdrawal in the investigator's judgment). Of the pts in the Active Treatment Period, over 90% achieved JIA ACR 50 response at all study time points. Sustained JADAS and ACR remission was achieved by 42 (33%) pts and 17 (13%) pts, respectively. The mean improvements from baseline in JADAS disease activity at mth 24 of CLIPPER were largely maintained through CLIPPER2 A total of 109/127 (86%) CLIPPER participants entered CLIPPER2 (n=55 eoJIA, n=31 ERA, n=23 PsA), with 99 (78%) pts continuing in the Active Treatment Period. Overall, 84 (66%) pts completed 120 mths of follow-up; 27 (21%) while actively taking ETN. Thirty (24%) pts entered the Withdrawal Period from the Active Treatment Period (I.e., they discontinued ETN, either by meeting the Wallace defnition for clinically inactive disease for at least 6 months on ETN, or by having had a good clinical response and being deemed to beneft from withdrawal in the investigator's judgment). Of the pts in the Active Treatment Period, over 90% achieved JIA ACR 50 response at all study time points. Sustained JADAS and ACR remission was achieved by 42 (33%) pts and 17 (13%) pts, respectively. The mean improvements from baseline in JADAS disease activity at mth 24 of CLIPPER were largely maintained through CLIPPER2. Conclusion: The low numbers of evaluable pts notwithstanding, efficacy results were consistent with the profile of ETN, and treatment responses were considered clinically meaningful and durable with long-term treatment.