Study of Ivacaftor in Cystic Fibrosis Subjects 2 Through 5 Years of Age With a CFTR Gating Mutation

A Phase 3, 2-Part, Open-Label Study to Evaluate the Safety, Pharmacokinetics and Pharmacodynamics of Ivacaftor in Subjects With Cystic Fibrosis Who Are 2 Through 5 Years of Age and Have a CFTR Gating Mutation

The purpose of this study is to evaluate the safety, pharmacokinetics (PK), and pharmacodynamics (PD), of ivacaftor in children with cystic fibrosis (CF) who are 2 through 5 years of age and have a CF Transmembrane Conductance Regulator (CFTR) gating mutation in at least 1 allele.

Part A is designed to evaluate the safety and PK of multiple-dose administration of ivacaftor in participants 2 through 5 years of age and to confirm the doses for Part B. Part B is designed to evaluate the safety, PK, PD, and efficacy of ivacaftor in participants 2 through 5 years of age.

Inclusion Criteria:

• Male or female with confirmed diagnosis of CF
• Must have a CFTR gating mutation in at least 1 allele
• Aged 2 through 5 years at screening and Day 1
• Weight >= 8 kg at screening and Day 1
• Hematology, serum chemistry, coagulation, and vital signs results at screening with no clinically significant abnormalities that would interfere with the study assessments, as judged by the investigator

Exclusion Criteria:

• History of any illness or condition that, in the opinion of the investigator, might confound the results of the study or pose an additional risk in administering study drug to the participant
• An acute upper or lower respiratory infection, or pulmonary exacerbation, or changes in therapy for pulmonary disease within 4 weeks before Day 1
• Abnormal liver function, at screening
• History of solid organ or hematological transplantation
• Use of any moderate or strong inducers or inhibitors of cytochrome P450 (CYP) 3A within 2 weeks before Day 1
• Participation in a clinical study involving administration of either an investigational or a marketed drug within 30 days or 5 terminal half-lives before screening