EPS05.3 Ivacaftor and its effects on body composition in adults with G551D related cystic fibrosis

Abstract

Background Ivacaftor, a potentiating agent has been shown to improve weight and BMI in patients with at least one copy of CFTR-G551D mutation. Effects on body composition are less well reported. Objectives To evaluate changes in body composition following ivacaftor therapy. Methods Twenty patients were included in a placebo-controlled crossover study of ivacaftor (28day treatment period), with 3 month open label extension. Bioelectrical impedance analysis (BIA) was conducted to measure weight, fat mass (FM), fat free mass (FFM), skeletal muscle mass (SMM) and total body water (TBW). Results Weight significantly increased above baseline at 1 month and post 3 months of ivacaftor treatment. FFM, SMM and TBW significantly increased following 1 month. FM did not significantly increase with 1 month of ivacaftor treatment but increased significantly above baseline post 3 months. Endpoint1 month (Crossover Study)+ 3 month Follow-Up (Open Label)% D Weight, kg1.6 (0.7, 2.5) *** 3.9 (2.4, 5.3) *** % D FM, kg0.9 (−2.4, 4.2)13.3 (5.0, 21.6) ** % D FFM, kg1.9 (0.9, 2.8) *** 0.6 (−1.9, 3.2)% D SMM, kg2.4 (0.6, 4.2) ** 1.6 (0.04, 3.2) * % D TBW, L2.0 (0.8, 3.2) *** 1.7 (0.3, 3.1) * Values are mean (95% CI).*P Conclusion The significant increase in weight is comparable to other seminal papers. The increase in FFM and SMM in the first 28days reflects an increase in TBW. Increase in FM did not occur until after 1month of treatment. These changes impact on nutrition practice. To our knowledge, this study is the first to investigate body composition with ivacaftor treatment using the BIA method. Validation with DEXA is underway. This study was supported by Vertex Inc.