The effect of elexacaftor/tezacaftor/ivacaftor (ETI) on glycemia in adults with cystic fibrosis.

ABSTRACT

BACKGROUND: Cystic fibrosis related diabetes (CFRD) is associated with pulmonary decline and compromised nutritional status. Emerging data suggest that CFTR dysfunction may play a direct role in the pathogenesis of CFRD; however, studies investigating the effect of CFTR modulators on glycemic outcomes in patients with cystic fibrosis (CF) have shown mixed results. The impact of elexacaftor-tezacaftor-ivacaftor (ETI) on glycemic control is currently unknown. Our objective was to investigate the effect of ETI initiation on glycemia in adults with CF using continuous glucose monitoring (CGM). METHODS: In this prospective observational study, 34 adults with CF and at least one F508del CFTR mutation wore CGM sensors for 14 days prior to starting ETI and again 3-12 months after ETI initiation. Hypoglycemia symptoms were queried at each visit, and most recent anthropometric measures and spirometry data were obtained by chart review. RESULTS: Twenty-three participants completed the study. Compared to baseline, average glucose (AG), standard deviation (SD), % time >200 mg/dL, and peak sensor glucose decreased with ETI treatment, and % time in target range 70-180 mg/dL increased. Improvements in glycemic parameters were most notable in individuals with CFRD. There was no significant change in CGM-measured or self-reported hypoglycemia before and after ETI initiation. CONCLUSION: Initiation of ETI in adults with CF was associated with improvement CGM-derived measures of hyperglycemia and glycemic variability with no effect on hypoglycemia. Further studies are needed to investigate underlying etiology of these changes and the long-term impact of ETI on glycemic control in patients with CF.