Ivacaftor therapy is shown to improve insulin secretion in young patients with cystic fibrosis (CF) coupled with impaired glucose tolerance, according to a study published in American Journal of Respiratory and Critical Care Medicine.

The study included 12 children (6 boys and 6 girls), younger than 18 years of age from Italy and North America. All participants had been diagnosed with CF and were studied at Children’s Hospital of Philadelphia in Pennsylvania. Mixed meal tolerance tests, oral glucose tolerance tests, and glucose-potentiated arginine tests were administered to participants at the onset of the study and 16 weeks after the introduction of ivacaftor for comparison.

Ivacaftor treatment was not shown to alter meal responses, but researchers noted an increase in early-phase C-peptide (P =.04). First-phase (P =.001) and glucose-potentiation of arginine-induced (P =.027) insulin secretion as assessed by acute C-peptide responses did improve after the initiation of ivacaftor treatment. As is expected with an effect on β-cell function, the disposition index relating the quantity of insulin secreted for insulin sensitivity improved as well (P =.04).

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Researchers concluded that “[i]nsulin secretion improved following four months of clinically-indicated ivacaftor therapy in this relatively young group of CF patients with normal to mildly impaired glucose tolerance.” They determined that the implications in preventing or delaying CF-related diabetes calls for further investigation.


Kelly A, De Leon D, Sheikh S, et al. Islet hormone and incretin secretion in cystic fibrosis following 4-months of ivacaftor therapy [published online August 21, 2018]. Am J Respir Crit Care Med. doi:10.1164/rccm.201806-1018OC