Ivacaftor (Kalydeco) treatment improves airway flexibility and capacity in patients with cystic fibrosis, according to a new study.
Researchers hypothesized that CFTR loss is the primary cause leading to defects in ASM function, and restoring CFTR activity would decrease smooth muscle tone in CF patients. To investigate this hypothesis, they potentiated CFTR function by administrating ivacaftor to 12 adults with CF and the G551D-CFTR mutation. Ivacaftor is a drug used to treat CF in people with certain mutations, and has been shown to increase CFTR activity in those with CFTR gating mutations.
The team studied patients before treatment, and had them perform tests including spirometry, whole-lung inspiratory, and expiratory chest CT scanning, and non-invasive measures of vascular tone. After starting ivacaftor therapy (48 hours later), patients returned to the clinic and repeated the exams. CFTR function was determined by measuring sweat chloride concentrations.
Results indicated that ivacaftor rapidly restored CFTR function, as shown by decreased sweat chloride concentration. Increased CFTR function was accompanied by significant improvements in airflow obstruction and air trapping. The team also assessed smooth muscle function in a tissue outside the lung, and observed that the vascular pulse wave velocity, and augmentation index, decreased following CFTR function potentiation.