A Phase 3 Study of VX-659 Combination Therapy in Subjects With Cystic Fibrosis Heterozygous for the F508del Mutation and a Minimal Function Mutation (F/MF)

Absolute Change in Cystic Fibrosis Questionnaire Revised (CFQ-R) Respiratory Domain Score

The CFQ-R is a validated participant-reported outcome measuring health-related quality of life for participants with cystic fibrosis. Respiratory domain assessed respiratory symptoms, score range: 0-100; higher scores indicating fewer symptoms and better health-related quality of life.

Time frame: From Baseline at Week 4

Time-to-first Pulmonary Exacerbation (PEx)

Pulmonary exacerbation was defined as the treatment with new or changed antibiotic therapy (intravenous, inhaled, or oral) for greater than or equal to 4 sinopulmonary signs/symptoms.

Time frame: From Baseline through Week 24

Absolute Change in BMI Z-score for Participants <=20 Years of Age at Baseline

BMI was defined as weight in kg divided by height in m\^2. z-score is a statistical measure to describe whether a mean was above or below the standard. BMI, adjusted for age and sex, was analyzed as BMI-for-age z-score. A z-score of 0 is equal to the mean and is considered normal. Lower numbers indicate values lower than the mean and higher numbers indicate values higher than the mean. Higher values are indicative of higher BMI.

Time frame: From Baseline at Week 24

Absolute Change in Body Weight

Time frame: From Baseline at Week 24

Safety and Tolerability as Assessed by Number of Participants With Treatment-Emergent Adverse Events (AEs) and Serious Adverse Events (SAEs)

Time frame: From first dose of study drug in TC treatment period up to 28 days after last dose of study drug or to the completion of study participation date, whichever occurs first (up to 28 weeks)

Observed Pre-dose Concentration (Ctrough) of VX-659, TEZ, M1-TEZ, and IVA

Time frame: Pre-dose on Week 4, 8, 12, and 16