Chronic incretin-based therapy in cystic fibrosis-related diabetes: A tale of 3 patients treated with sitagliptin for over 5 years.

Cystic fibrosis-related diabetes (CFRD) affects 40-50% of adult patients with cystic fibrosis. Insulin therapy is recommended but there are therapeutic challenges, particularly risk of hypoglycemia and aversion of some patients to injectables. An oral incretin-based therapy using a DPP-4i (dipeptidyl peptidase-4 inhibitor), may be a reasonable option, especially in the early stage of the disease. The effect of chronic incretin-based therapy on CFRD is unknown. Here is a report of 3 cases of CFRD patients treated with sitagliptin and the response to therapy over a period of 5-10 years. An effective glycemic control was demonstrated in all the patients, at least during the first 5 years of sitagliptin treatment, and the benefit persisted for a decade in two of them. The secondary failure of the DPP-4i occurred in a CFRD patient with a phenotype resembling type 2 diabetes. A DPP-4i may have an important role in the management of CFRD.