Hartmut Grasemann1, Tanja Gonska2, Julie Avolio3, Michelle Klingel4, Elizabeth Tullis5, Felix Ratjen1. 1. Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Canada; Program in Physiology and Experimental Medicine, SickKids Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Canada. 2. Division of Gastroenterology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Canada; Program in Physiology and Experimental Medicine, SickKids Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Canada. 3. Division of Gastroenterology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Canada. 4. Program in Physiology and Experimental Medicine, SickKids Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Canada. 5. Division of Respirology and Keenan Research Centre of Li Ka Shing Knowledge Institute, Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Canada.
Abstract
UNLABELLED: Airways of patients with cystic fibrosis are deficient for nitric oxide. Low nitric oxide in cystic fibrosis has been shown to be associated with poor pulmonary function and risk of infection with certain pathogens. Treatment of cystic fibrosis patients with the cystic fibrosis transmembrane conductance regulator (CFTR)-targeting drug ivacaftor results in improved pulmonary function. The effect of ivacaftor on airway nitric oxide has not been assessed. METHODS: In this observational trial, fractional exhaled nitric oxide (FE(NO)) was measured before and 4 weeks after initiation of ivacaftor therapy, in patients with cystic fibrosis and a CFTR gating mutation. The effect of ivacaftor on FE(NO) was compared to treatment with inhaled dornase alfa or hypertonic saline for 4 weeks, respectively. RESULTS: A total of 15 patients on ivacaftor therapy were studied. Pulmonary function improved significantly and mean (±SD) FE(NO) increased from 8.5±5.0 to 16.2±15.5 ppb. The effect was more pronounced in pediatric compared to adult patients. There was no linear correlation between changes in FE(NO), pulmonary function or sweat chloride concentration. Neither treatment with inhaled dornase alfa (n=15) or hypertonic saline (n=16) resulted in a change in FE(NO). CONCLUSION: Therapy with ivacaftor results in an increase in nitric oxide formation in cystic fibrosis airways, while dornase alfa or hypertonic saline has no effect on airway nitric oxide. Some beneficial effects of CFTR targeting therapy in CF may result from improved airway nitric oxide production.
UNLABELLED: Airways of patients with cystic fibrosis are deficient for nitric oxide. Low nitric oxide in cystic fibrosis has been shown to be associated with poor pulmonary function and risk of infection with certain pathogens. Treatment of cystic fibrosispatients with the cystic fibrosis transmembrane conductance regulator (CFTR)-targeting drug ivacaftor results in improved pulmonary function. The effect of ivacaftor on airway nitric oxide has not been assessed. METHODS: In this observational trial, fractional exhaled nitric oxide (FE(NO)) was measured before and 4 weeks after initiation of ivacaftor therapy, in patients with cystic fibrosis and a CFTR gating mutation. The effect of ivacaftor on FE(NO) was compared to treatment with inhaled dornase alfa or hypertonicsaline for 4 weeks, respectively. RESULTS: A total of 15 patients on ivacaftor therapy were studied. Pulmonary function improved significantly and mean (±SD) FE(NO) increased from 8.5±5.0 to 16.2±15.5 ppb. The effect was more pronounced in pediatric compared to adult patients. There was no linear correlation between changes in FE(NO), pulmonary function or sweat chloride concentration. Neither treatment with inhaled dornase alfa (n=15) or hypertonicsaline (n=16) resulted in a change in FE(NO). CONCLUSION: Therapy with ivacaftor results in an increase in nitric oxide formation in cystic fibrosis airways, while dornase alfa or hypertonicsaline has no effect on airway nitric oxide. Some beneficial effects of CFTR targeting therapy in CF may result from improved airway nitric oxide production.
Authors: Jonathan Grigg; Jürg Barben; Kajsa Bohlin; Mark L Everard; Graham Hall; Mariëlle Pijnenburg; Kostas N Priftis; Franca Rusconi; Fabio Midulla Journal: ERJ Open Res Date: 2016-04-29