Safety and Pharmacokinetic Study of Lumacaftor/Ivacaftor in Subjects Aged 2 Through 5 Years With Cystic Fibrosis, Homozygous for F508del

A Phase 3, 2-Part, Open-label Study to Evaluate the Safety and Pharmacokinetics of Lumacaftor/Ivacaftor Combination Therapy in Subjects Aged 2 Through 5 Years With Cystic Fibrosis, Homozygous for the F508del-CFTR Mutation

This is a Phase 3, 2-part (Part A and Part B), open-label, multicenter study evaluating the pharmacokinetics (PK), safety, tolerability, and pharmacodynamics (PD) of multiple doses of lumacaftor/ivacaftor (LUM/IVA) in subjects 2 through 5 years of age (inclusive) with cystic fibrosis (CF), homozygous for F508del. Subjects who participate in Part A may participate in Part B, if they meet the eligibility criteria.

Inclusion Criteria:

• Subjects who weigh ≥8 kilogram (kg) without shoes and wearing light clothing at the Screening Visit
• Subjects with confirmed diagnosis of CF at the Screening Visit
• Subjects who are homozygous for the F508del-cystic fibrosis transmembrane conductance regulator (CFTR) mutation

Exclusion Criteria:

• Any clinically significant laboratory abnormalities at the Screening Visit that would interfere with the study assessments or pose an undue risk for the subject
• An acute upper or lower respiratory infection, pulmonary exacerbation, or changes in therapy (including antibiotics) for pulmonary disease within 28 days before Day 1
• A standard 12-lead ECG demonstrating QTc >450 millisecond (msec) at the Screening Visit.
• History of solid organ or hematological transplantation.
• Ongoing or prior participation in an investigational drug study (including studies investigating LUM and/or IVA) within 30 days of the Screening Visit.
• History of cataract/lens opacity or evidence of cataract/lens opacity determined to be clinically significant by a licensed ophthalmologist during the ophthalmologic examination at the Screening Visit