Ivacaftor as salvage therapy in a patient with cystic fibrosis genotype F508del/R117H/IVS8-5T.

Ivacaftor is a novel CFTR potentiator that increases CFTR activity and improves clinical outcomes in cystic fibrosis (CF) patients with at least one copy of CFTR-G551D. Clinical trials have shown an improvement in lung function, weight and CF pulmonary exacerbation in adults with CFTR-G551D leading to the approval of ivacaftor as a novel CF therapy [1]. In vitro studies of ivacaftor have also shown significant improvements in CFTR chloride channel opening time in other non-G551D CFTR mutations suggesting that ivacaftor may be of benefit to patients with mutations other than gating mutations [2]. R117H-CFTR is a relatively common CFTR mutation that demonstrates an in-vitro response to ivacaftor [2,3]. A clinical trial has suggested that there may be a role for ivacaftor in older patients with R117H-CFTR although this trial did not include patients with very severe CF lung disease [4]. In 2014, ivacaftor was approved in the United States as a treatment for CF subjects aged greater than 6 years old with a copy of R117H-CFTR. We present a case demonstrating a substantial therapeutic effect of ivacaftor in a CF patient with genotype F508del/R117H and advanced lung disease.