A Phase 3, 2-part, Open-label Study to Evaluate the Safety and Pharmacokinetics of Lumacaftor/Ivacaftor in Subjects 1 to Less Than 2 Years of Age With Cystic Fibrosis, Homozygous for F508del

Primary objectives Part a To evaluate the PK of lumacaftor (LuM) and ivacaftor (iVa) in subjects 1 to less than 2 years of age with cystic fibrosis (CF), homozygous for F508del Part B To evaluate the safety of LuM/iVa in subjects 1 to less than 2 years of age with CF, homozygous for F508del Secondary objectives Part a * To evaluate the safety of LuM/iVa in subjects 1 to less than 2 years of age with CF, homozygous for F508del * To evaluate the PK of the metabolites of LuM and iVa in subjects 1 to less than 2 years of age with CF, homozygous for F508del Part B * To evaluate the pharmacodynamics (PD) of LuM/iVa in subjects 1 to less than 2 years of age with CF, homozygous for F508del * To evaluate the PK of LuM and iVa and their respective metabolites in subjects 1 to less than 2 years of age with CF, homozygous for F508del