Abstract 679: Efficacy of Abatacept in Different Sub-Populations of Juvenile Idiopathic Arthritis (JIA): Results of a Randomized Withdrawal Study
Sangeeta Sule, M.D.
Authors:
E. H. Giannini, N. Ruperto, A. M. Prieur, E. Paz, N. E. Rubio-Perez, C. A. Silva, C. Abud, R. Burgos-Vargas, V. Gerloni, J. Melo-Gomes, C. S. Magalhaes, F. Sztajnbok, C. Goldenstein-Schainberg, M. Scheinberg, P. Hashkes, C. Hom, L. H. Sigal, A. J. Block, A. Covucci, D. J. Lovell, A. Martini
Background:
Abatacept (ABA) is a “costimulation modulator,” blocking signaling required for antigen-specific T cell activation. ABA has been effective in treating adult patients with rheumatoid arthritis and in a previous open-label study of children with juvenile idiopathic arthritis (JIA). In this abstract, the authors performed a sub-analysis to determine efficacy of ABA within JIA categories.
Methods:
190 patients aged 6-17 years who had continued active disease not responsive to ≥ 1 DMARD were enrolled in the 4-month open label lead-in period. Patients were treated with ABA (10mg/kg IV) on Day 1, 15, 29, and every 28 days thereafter until Day 113 and were permitted to receive methotrexate 10-30 mg/m2/week.
Results:
170 patients completed the lead-in period. 77.4% of patients were Caucasian with a female predominance (72.1%). 64.2% of patients had polyarticular JIA (20% rheumatoid factor positive), 19.5% systemic JIA, 14.2% extended oligoarticular JIA, and 1.6% persistent oligoarticular JIA. ACR Pedi 30 response rates were similar across disease subsets with 26/38 (68.4%) response in polyarticular rheumatoid factor positive patients, 54/84 (64.3%) in polyarthritis-rheumatoid factor negative patients, 24/37 (64.9%) in systemic JIA patients, 16/27 (59.3%) in oligoarticular-extended patients, and 2/2 (100%) in persistent oligoarticular patients. In patients who had previously received biologic therapy (30% of the total population), response rates were 38.6%, 24.6%, 10.5%, and 1.8%, respectively, in the different subgroups.
Conclusions:
ABA was effective treatment across all JIA categories enrolled in the study.
Editorial Comment:
This abstract shows efficacy of ABA across subsets of JIA. This is important because previous biologic therapy (such as tumor-necrosis factor alpha blockade) has had mixed results with different subsets of JIA, with a particularly weak response in systemic onset JIA. The results of this abstract are encouraging; however, the initial study may not have been powered to detect differences across subsets. For example, only 2 oligoarticular-extended patients had ACR Pedi 30 responses, but this was 100% of that subset. In the future, studies powered to include appropriate numbers of patients across subsets of JIA may give more information on effectiveness of ABA and other treatments.
