Effects of ivacaftor on severely ill patients with cystic fibrosis carrying a G551D mutation

BackgroundRecently, ivacaftor, a CFTR-potentiator, has been shown to be effective and safe in patients with cystic fibrosis carrying a G551D mutation and moderately impaired lung function. The objective of this retrospective study was to assess efficacy and safety of ivacaftor in severely ill patients with at least one G551D mutation.MethodsData from 14 patients with a FEV1 < 40% predicted who received ivacaftor on a “named patient program” base in Germany were analyzed.ResultsOne patient took ivacaftor at a lower than recommended dose due to abundant mucus and a feeling to “suffocate.” No additional severe adverse events were reported. One further patient stopped ivacaftor due to lung transplantation, one due to perceived poor effectiveness, one due to pregnancy, and one stopped standard therapy. The remaining patients took ivacaftor regularly and did not change other therapies. FEV1 increased by more than 5 %predicted in 5 of the 14 patients from baseline (average FEV1 during the year prior to ivacaftor). On average, FEV1 increased significantly by 5.2 ± 5.6%predicted (p < 0.01). The relative improvement in FEV1 was 19.7 ± 22.1%.ConclusionIvacaftor was effective in many patients with poor lung function. The response was, however, variable. Although the drug appeared safe for most of these patients, increased bronchial secretions may warrant intensified physiotherapy and intravenous antibiotic treatment when ivacaftor is initiated.