SAT0515 GROWTH AND DEVELOPMENT OF PATIENTS WITH POLYARTICULAR-COURSE JUVENILE IDIOPATHIC ARTHRITIS TREATED WITH SUBCUTANEOUS ABATACEPT

Background Efficacy of SC abatacept (ABA) in patients (pts) with polyarticular-course juvenile idiopathic arthritis (pJIA) was shown in a 2-year, open-label, Phase III international study (NCT01844518).1 Restricted growth and delayed puberty are associated with pJIA;2 however, the effect of ABA on growth and development is unknown. Objectives To investigate the effect of ABA on height, BMI and Tanner staging, and to assess the impact of BMI on ABA efficacy in pts with pJIA. Methods Patients with pJIA were grouped into two age cohorts (2–5 and 6–17 years [yrs]) and received weight-tiered SC ABA (10 to −2 to ≤1), overweight (>1 to ≤2) and obese (>2) (intent-to-treat, non-responder imputation for missing efficacy data). In the 6–17-yr cohort, Tanner staging was recorded at BL and at discontinuation or completion of study. Results Data for standardised height and BMI are presented. In 6–17-yr-old pts with BL Tanner stage ≤3 (n=100), BL mean (SD) height was −0.53 (1.53); at D645, mean (95% CI) change was 0.20 (0.06, 0.34; Figure 1). In 6–17-yr-old pts with a BL height ≤−1 (n=42), BL mean (SD) height was −2.10 (1.01) and mean (95% CI) change at D645 was 0.49 (0.23, 0.76). In 2–5-yr-old pts, BL mean (SD) height was 0.07 (1.37); at D645, mean (95% CI) change was 0.13 (−0.09, 0.36). In 13 pts aged 6–17 yrs of the lowest height (Tanner stage ≤3 and BL height ≤−2), mean (SD) height increased from −3.28 (1.10) at BL to −2.59 (1.31) by D645. At BL, mean (SD) BMI was 0.20 (1.33) in the 6–17-yr cohort (n=173) and 0.25 (1.57) in the 2–5-yr cohort (n=46); at D645, mean (95% CI) change in BMI was 0.02 (−0.13, 0.16; Figure 2) and 0.17 (−0.08, 0.42), respectively. Overall, no relationship was seen between change from BL in Juvenile Arthritis Disease Activity Score 71 (JADAS71) and BL BMI in either age cohort. The proportions (odds ratio [OR]; 95% CI of OR) of obese pts aged 6–17 yrs achieving JIA-ACR30 (0.15; 0.04, 0.55), JIA-ACR50 (0.18; 0.05, 0.63), JIA-ACR70 (0.17; 0.04, 0.67) and JADAS71 minimal disease activity (0.27; 0.07, 1.03) at Day 645 were significantly lower compared with pts with a normal BMI, but the sample size in the obese category was low (n=12); this effect was not seen in overweight pts (n=37). In female pts (n=92), shifts in Tanner stages from BL to D645 were as expected; male sexual maturation was difficult to assess due to the small sample size (n=20). Conclusion Abatacept improves growth and development in pts with pJIA. Early therapeutic intervention with abatacept may help reduce growth restrictions in pts with pJIA. BMI may impact the efficacy response, resulting in lower efficacy in obese, but not in overweight, pts with pJIA versus pts with normal BMI. References [1] Brunner HI, et al. Arthritis Rheumatol2018;70:1144–54. [2] Umlawska W, et al. Arch Med Sci2010;6:19–23. Acknowledgement Professional medical writing: Lola Parfitt, MRes, Caudex; funding: Bristol-Myers Squibb Disclosure of Interests Nicolino Ruperto Grant/research support from: The Gaslini Hospital, where NR works as full-time public employee, has received contributions (> 10.000 USD each) from the following industries in the last 3 years: BMS, Eli-Lilly, GlaxoSmithKline, F Hoffmann-La Roche, Janssen, Novartis, Pfizer, Sobi. This funding has been reinvested for the research activities of the hospital in a fully independent manner, without any commitment with third parties., Consultant for: Received honoraria for consultancies or speaker bureaus ( I perform consultancy activities on behalf of the Gaslini Institute for the companies listed below: AbbVie, Biogen, Boehringer Ingelheim, Bristol-Myers Squibb, EMD Serono, Janssen, Novartis, Pfizer, R-Pharm. The money received for these activities are directly transferred to the Gaslini Institute’s bank account. Before March 2016, I was the head of the Pediatric Rheumatology Department at the G. Gaslini Hospital, where the PRINTO Coordinating Centre is located. For the coordination activity of the PRINTO network, the Gaslini Hospital received contributions from the industries listed in this section. This money has been reinvested for the research activities of the hospital in fully independent manners besides any commitment with third parties., Daniel J Lovell Consultant for: Consulting fees and/or honoraria from Astra Zeneca, Wyeth Pharma, Amgen, Abbott, Pfizer, F. Hoffmann-La Roche, Novartis, UBC, Takeda, GSK, Boehringer, and Celgene