CFTR potentiator therapy ameliorates impaired insulin secretion in CF patients with a gating mutation

Objective: To investigate the effect of treatment with ivacaftor on insulin secretion in patients with cystic fibrosis (CF) (δF508\S549R) having CFRD/impaired insulin secretion. Methods: A standard OGTT was performed before and after 16 weeks of treatment with ivacaftor in 2 sibling patients with CF carrying the S549R gating mutation. The area under the curve (AUC) for glucose and insulin was calculated using the trapezoidal estimation. Results: Before treatment, the OGTT of case 1 showed indeterminate glycemia; the OGTT of case 2 indicated CFRD. After ivacaftor treatment the OGTT demonstrated improved insulin secretion pattern mainly by increased first phase early insulin secretion, resulting in reduction of the AUC of glucose in both cases. Conclusions: The treatment with ivacaftor in patients with CF carrying gating mutation can ameliorate impaired insulin secretion. Further studies and larger cohorts are needed to evaluate the impact of ivacaftor on insulin secretion in patients with CF carrying gating or other mutations.