A Study to Evaluate the Effect of VX-661 in Combination With Ivacaftor on Chest Imaging Endpoints in Subjects With Cystic Fibrosis, Homozygous for the F508del CFTR Mutation

A Phase 2, Randomized, Placebo-Controlled, Double-blind Study to Evaluate the Effect of VX-661 in Combination With Ivacaftor on Chest Imaging Endpoints in Subjects Aged 12 Years and Older With Cystic Fibrosis, Homozygous for the F508del CFTR Mutation

The primary purpose of study is to evaluate the treatment effect of tezacaftor in combination with ivacaftor (TEZ/IVA) on chest imaging endpoints using low-dose computed tomography (LDCT) at Week 72, and to evaluate the safety of TEZ/IVA through Week 72.

Inclusion Criteria:

• Homozygous for the F508del CFTR mutation
• Confirmed diagnosis of CF
• Percent predicted forced expiratory volume (ppFEV1) ≥70% 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.
• An acute upper or lower respiratory infection, pulmonary exacerbation, or changes in therapy (including antibiotics) for pulmonary disease within 28 days before Day 1 (first dose of study drug)
• Pregnant or nursing females.
• Sexually active subjects of reproductive potential who are not willing to follow the contraception requirements.
• Any contraindication to undergoing chest imaging, as per the site's institutional guidelines