The effect of ivacaftor (VX-770, registered in Australia as Kalydeco) on exocrine pancreatic function in patients 6 years and older with cystic fibrosis and at least one copy of the G551D CFTR mutation and who are naive for ivacaftor

This study is looking at how a drug called ivacaftor (Kalydeco) affects the pancreas in patients with cystic fibrosis who have a specific genetic mutation called G551D. Many people with cystic fibrosis have poor pancreatic function and need enzyme supplements to digest food. Researchers want to see if ivacaftor helps the pancreas work better. You may be eligible if: - You are 6 years of age or older - You have a confirmed diagnosis of cystic fibrosis - You carry at least one copy of the G551D gene mutation - You currently take pancreatic enzyme replacement therapy - You have never received ivacaftor before You may NOT be eligible if: - You are allergic to ivacaftor or any of its ingredients - You have had an organ transplant - You are taking certain antifungal medications, antibiotics, or other drugs that interact with ivacaftor - You have severe liver or kidney disease - You are pregnant, planning to become pregnant, or breastfeeding Talk to your doctor about whether this trial might be right for you.