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

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).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.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 flare 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.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 definition for clinically inactive disease for at least 6 months on ETN, or by having had a good clinical response and being deemed to benefit 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 definition for clinically inactive disease for at least 6 months on ETN, or by having had a good clinical response and being deemed to benefit 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.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.[1]Foeldvari I, et al. Arthritis Res Ther 2019;21:125.[2]Trincianti C, et al. Arthritis Rheumatol 2021:73;1966-75.Trial Registration:NCT00962741/NCT01421069Medical writing support was provided by Iain McDonald, PhD, of Engage Scientific Solutions and was funded by Pfizer.Jelena Vojinovic Speakers bureau: Abbvie, Roche, Sandoz, Joke Dehoorne Speakers bureau: Abbvie, Roche, Consultant of: Abbvie, Roche, Violeta Panaviene: None declared, Gordana Susic: None declared, Gerd Horneff Speakers bureau: Chugai, Eli-Lilly, Glaxo Smith and Kline, Janssen, Novartis, Pfizer, Roche and Sobi, Grant/research support from: Novartis, Janssen, Roche, Valda Stanevicha Speakers bureau: Sandoz, Abbvie, Roche, Katarzyna Kobusinska: None declared, Zbigniew Żuber: None declared, Bogna Dobrzyniecka: None declared, Jonathan Akikusa: None declared, Tadej Avcin Speakers bureau: AbbVie, Octapharma and Takeda, Consultant of: AbbVie, Octapharma and Takeda, Alberto Martini Speakers bureau: Aurinia, Bristol Myers and Squibb, Eli-Lilly, EMD Serono, Janssen, Pfizer, Roche, Consultant of: Aurinia, Bristol Myers and Squibb, Eli-Lilly, EMD Serono, Janssen, Pfizer, Roche, Cecilia Borlenghi Shareholder of: Pfizer, Employee of: Pfizer, Edmund Arthur Employee of: Pfizer, Svitlana Y Tatulych Shareholder of: Pfizer, Employee of: Pfizer, Chuanbo Zang Shareholder of: Pfizer, Employee of: Pfizer, Vasileios TSEKOURAS Shareholder of: Pfizer, Employee of: Pfizer, Bonnie Vlahos Shareholder of: Pfizer, Employee of: Pfizer, Nicolino Ruperto Speakers bureau: Ablynx, Amgen, Astrazeneca-Medimmune, Aurinia, Bayer, Bristol Myers and Squibb, Cambridge Healthcare Research (CHR), Celgene, Domain therapeutic, Eli-Lilly, EMD Serono, Glaxo Smith and Kline, Idorsia, Janssen, Novartis, Pfizer, Sobi, UCB., Consultant of: Ablynx, Amgen, Astrazeneca-Medimmune, Aurinia, Bayer, Bristol Myers and Squibb, Cambridge Healthcare Research (CHR), Celgene, Domain therapeutic, Eli-Lilly, EMD Serono, Glaxo Smith and Kline, Idorsia, Janssen, Novartis, Pfizer, Sobi, UCB.