This is a study of the short-term effects of ivacaftor on sweat chloride concentration and lung function in cystic fibrosis (CF) patients who fall outside current FDA approval. This new, first of its kind drug is approved for use only in CF patients with the G551D mutation in whom it safely confers considerable benefits. However, it is highly likely that CF patients with many other mutations can benefit similarly from this drug, some of whom can be identified by phenotype or genotype. We will enroll up to 30 CF subjects with clinical presentations in which there is one or more signs of residual CF channel function. The signs of residual function include: normal digestion, concentration of chloride in sweat between 55 and 85, or milder than expected CF disease in a CF patient with severe gene mutations. The primary outcome measure will be the difference in sweat chloride concentration measured in subjects on placebo and on ivacaftor. Secondary outcome measured will be lung function.
Name: ivacaftor
Description: Sweat chloride concentration measured by pilocarpine iontophoresis, a standard clinical laboratory technique. Sweat collection accomplished with the Wescor Macroduct system. Sweat chloride is measured at the start and end of each study period. There are two study periods during which subjects take either ivacaftor or placebo.
Measure: Sweat chloride concentration Time: 14 +/- 2 daysDescription: Standard spirometry will be performed at the start and end of each 2 week study period. Subjects will take study drug (ivacaftor or placebo during each study period.
Measure: Spirometry Time: 14 +/- 2 daysDescription: Subjects will perform multibreath washout testing using standard techniques to measure functional residual capacity and lung clearance index at the beginning and end of each study period.
Measure: Multibreath washout testing Time: 14 +/- 2 daysAllocation: Randomized
Crossover Assignment
There is one SNP
Short Term Effects of Ivacaftor in Non-G551D Cystic Fibrosis Patients. --- G551D ---
Short Term Effects of Ivacaftor in Non-G551D Cystic Fibrosis Patients This is a study of the short-term effects of ivacaftor on sweat chloride concentration and lung function in cystic fibrosis (CF) patients who fall outside current FDA approval. --- G551D ---
This new, first of its kind drug is approved for use only in CF patients with the G551D mutation in whom it safely confers considerable benefits. --- G551D ---
It is currently FDA approved for use only in CF patients with the G551D gating mutation. --- G551D ---
Based on results from previous studies, we hypothesize that non-G551D patients with signs of residual CF channel activity might respond favorably to treatment with ivacaftor. --- G551D ---
This includes patients with any of the non-G551D gating mutations, that are pancreatic sufficient, that have a sweat chloride concentration between 55 and 85 mmol, or that are much healthier than expected. --- G551D ---