Conditions: Cystic Fibrosis
Keywords: G551D mutation Fibrosis Pancreatic Diseases Digestive System Diseases Lung Diseases Respiratory Tract Diseases Genetic Diseases, Inborn Infant, Newborn, Diseases Pathologic Processes
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 39
Healthy volunteers: no

Brief summary:
The purpose of this study was to evaluate the safety and tolerability of ivacaftor in patients with cystic fibrosis (CF) who were aged 18 years or older and have a G551D mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Ivacaftor is a potent and selective CFTR potentiator of wild-type, G551D, F508del, and R117H forms of human CFTR protein. Potentiators are pharmacological agents that increase the chloride ion transport properties of the channel in the presence of cyclic AMP-dependent protein kinase A (PKA) activation.

Detailed description:
This was a double-blind, placebo-controlled, cross-over, multiple dose study of up to 28 days of dosing, in subjects with cystic fibrosis (CF) who have a G551D-CTFR gene mutation. Enrollment of 39 subjects occurred at 15 centers in the US, Canada, and Germany.

The study was conducted in 2 parts:

* Part 1 consisted of Group A and Group B. Subjects in Group A (10 subjects) were randomized to receive 25 mg of ivacaftor every 12 hours \[q12h\] (4 subjects), 75 mg of ivacaftor q12h (4 subjects), or placebo (2 subjects) for 14 days. Following a 7- to 28-day washout period, subjects who received active study drug crossed over to the alternate dose strength of ivacaftor for an additional 14 days. Placebo subjects continued to receive placebo for an additional 14 days. Subjects in Group B (10 subjects) were randomized to receive 75 mg of ivacaftor q12h (4 subjects), 150 mg of ivacaftor q12h (4 subjects), or placebo (2 subjects) for 14 days. Following a 7- to 28-day washout period, the subjects who received active study drug crossed over to the alternate dose strength of ivacaftor for an additional 14 days. Placebo subjects continued to receive placebo for an additional 14 days.
* Part 2 consisted of Group C; these subjects did not participate in Part 1. Subjects were randomized to receive 150 mg of ivacaftor q12h (7 subjects), 250 mg of ivacaftor q12h (7 subjects), or placebo (4 subjects) for a total of 28 days. Ivacaftor doses studied in Part 2 were selected following an interim pharmacokinetic/pharmacodynamic (PK/PD) and statistical analyses of data from Part 1. The 2 doses selected for Part 2 were anticipated to enable better definition of the optimal therapeutic dose.

Arms:
arm 1: Subjects in Part 1 who first received 25 mg or 75 mg of ivacaftor every 12 hours (q12h) for 14 days, then crossed over to receive the alternate dose for another 14 days. arm 2: Subjects in Part 1 who first received 75 mg or 150 mg of ivacaftor q12h for 14 days then crossed over to receive the alternate dose for another 14 days. arm 3: Subjects in Part 2 who received 150 mg or 250 mg of ivacaftor q12h for 28 days. arm 4: Subjects who received placebo in Part 1 and subjects who received placebo in Part 2.

Interventions: intervention 1: Ivacaftor 25 mg/75 mg intervention 2: Ivacaftor 75 mg/150 mg intervention 3: Ivacaftor 150 mg or 250 mg intervention 4: Placebo
Intervention descriptions: intervention 1: 25 mg or 75 mg q12h for a total of 28 days (Part 1) intervention 2: 75 mg or 150 mg q12h for a total of 28 days (Part 1) intervention 3: 150 mg or 250 mg of ivacaftor q12h for 28 days (Part 2) intervention 4: Given q12h for 28 days each in Part 1 and Part 2 of the study

Protocol document: