['cystic fibrosis']
['iva', 'tez/iva', 'vx-445', 'matched placebo', 'tez', 'vx-561']

        Key Inclusion Criteria:

        Parts A, B, and C:

          -  Female subjects must be of non-childbearing potential.

          -  Between the ages of 18 and 55 years, inclusive.

          -  Body mass index (BMI) of 18.0 to 32.0 kg/m2, inclusive, and a total body weight >50 kg

        Parts D, E, and F:

          -  Body weight ≥35 kg.

          -  Subjects must have an eligible CFTR genotype:

               -  Parts D and F: Heterozygous for F508del and an MF mutation (F/MF)

               -  Part E: Homozygous for F508del (F/F)

          -  FEV1 value ≥40% and ≤90% of predicted mean for age, sex, and height.

        Key Exclusion Criteria:

        Parts A, B, and C:

          -  Any condition possibly affecting drug absorption.

          -  History of febrile illness within 14 days before the first study drug dose.

          -  Glucose-6-phosphate dehydrogenase (G6PD) deficiency.

        Parts D, E, and F:

          -  History of clinically significant cirrhosis with or without portal hypertension.

          -  Glucose-6-phosphate dehydrogenase (G6PD) deficiency.

          -  Lung infection with organisms associated with a more rapid decline in pulmonary
             status.

          -  History of solid organ or hematological transplantation.

        Other protocol defined Inclusion/Exclusion criteria may apply.
      