Elexacaftor/Tezacaftor/Ivacaftor Supports Treatment for CF with ΔI1023-V1024-CFTR

Cystic Fibrosis (CF) is a common genetic disease in the United States, resulting from mutations in the <i>Cystic Fibrosis transmembrane conductance regulator (cftr)</i> gene. CFTR modulators, particularly Elexacaftor/Tezacaftor/Ivacaftor (ETI), have significantly improved clinical outcomes for patients with CF. However, many CFTR mutations are not eligible for CFTR modulator therapy due to their rarity. In this study, we report that a patient carrying rare complex CFTR mutations, c.1680-877G>T and c.3067_3072delATAGTG, showed positive clinical outcomes after ETI treatment. We demonstrate that ETI was able to increase the expression of CFTR harboring c.3067_3072delATAGTG in a heterologous system. Importantly, patient-derived nasal epithelial cells in an air-liquid interface (ALI) culture showed improved CFTR function following ETI treatment. These findings supported the initiation of ETI with the patient. Retrospective studies have suggested that the patient has shown small but steady improvement over the past two years in several clinical metrics, including lung function, body mass index (BMI), and sweat chloride levels. Our studies suggest that ETI could be beneficial for patients carrying c.3067_3072delATAGTG.