Study design (if review, criteria of inclusion for studies)
Single-center, double-blind, placebo-controlled, 28-d, crossover study, followed by an open-label extension (OLE) for 5 mo.
Twenty adults with CF carrying the G551D mutation (mean ± standard deviation body mass index [BMI] 23.3 ± 4.3 kg/m(2)). Eleven patients underwent measurements 2 y later.
Weight, BMI, and body composition (including fat-free mass [FFM] and fat mass).
After 28 d of treatment with ivacaftor, weight increased by 1.1 ± 1.3 kg, BMI by 0.4 ± 0.5 kg/m(2), and FFM by 1.1 ± 1.2 kg (all P < .005) with no change in fat mass. Differences between 28-d changes on ivacaftor and placebo were not statistically significant. In the following 5 mo of the OLE, there were significant increases in weight (1.2 ± 1.9 kg; P < .05) and fat mass (1.5 ± 1.9 kg; P < .01), but not in FFM. Between baseline and the end of the OLE, the total weight gain was 2.5 ± 2.4 kg (P < .005), comprised of 0.9 ± 1.5 kg FFM (P < .05) and 1.6 ± 1.8 kg fat mass (P < .005). For the 11 participants who were followed for a further 2 y, no further changes in mean weight, BMI, or body composition parameters between 6 mo and 2 y later were observed.
Small gains were seen in FFM in the first month of ivacaftor treatment. Weight, BMI, and fat-mass gains in the first 6 mo on ivacaftor plateaued by 2.5 y. The metabolic and clinical consequences of weight and fat-mass gains remain to be determined.