Ivacaftor for the p.Ser549Arg (S549R) gating mutation - The Israeli experience

Abstract

Background: Ivacaftor is a drug that increases the probability of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel remaining open. Information about the efficacy of ivacaftor in patients carrying the rare p.Ser549Arg (S549R) CFTR mutation is sparse.

Aim: Efficacy of ivacaftor treatment in patients carrying the p.Ser549Arg (S549R) CFTR mutation.

Methods: Data obtained from CF patients receiving ivacaftor for one year.

Results: Eight CF patients, mean age 21 ± 10 years, received ivacaftor. After one year, significant improvement was found in FEV₁, increasing from 74% to 88% (p < 0.001), FVC, 89% to 101% (p = 0.019), and FEF_25-75, 59%-76% (p = 0.019). Sweat chloride concentration decreased from 116 ± 8 mmol/L to 51 ± 17 mmol/L (p < 0.001), and BMI increased from 20 ± 3 to 22 ± 4 (p = 0.003). Glucose tolerance improved in five patients. There was no significant change in bacterial colonization.

Conclusions: Ivacaftor therapy resulted in significant clinical improvement in patients carrying the p.Ser549Arg (S549R) CFTR mutation.

Keywords: Cystic fibrosis; Gating mutation; Ivacaftor; p.Ser549Arg (S549R).