['cystic fibrosis']
['ivacaftor', 'tezacaftor/ivacaftor']

        Inclusion Criteria:

          -  Heterozygous for F508del-CFTR mutation and a second CFTR allele with a gating defect
             that is clinically demonstrated to be ivacaftor responsive

          -  FEV1 ≥40% and ≤90% of predicted normal for age, sex, and height during screening

          -  Stable CF disease as judged by the investigator.

        Exclusion Criteria:

          -  History of any comorbidity 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
             subject.

          -  Pregnant and nursing females (females of childbearing potential must have a negative
             pregnancy test at Screening and Week -4 Visits).

          -  Sexually active subjects of reproductive potential who are not willing to follow the
             contraception requirements
      