Ivacaftor improved early-phase insulin secretion in CF patients carrying the S549R mutation, leading to the resolution of CFRD in one case.The improvement in insulin secretion may be mediated by CFTR reactivation in pancreatic β-cell. Further studies with larger cohorts are needed to confirm these findings and evaluate Ivacaftor’s efficacy in other CFTR mutations. The gene discussed is INS; the disease is cystic fibrosis.