Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Phase 2, Randomized, Double-Blind, Placebo-Controlled, Crossover Study to Evaluate the Effect of VX-770 on Lung Clearance Index in Subjects With Cystic Fibrosis, the G551D Mutation, and FEV1 >90% Predicted
Brief Summary: The purpose of this study is to evaluate the effect of ivacaftor (VX-770) on lung clearance index (LCI) in subjects aged 6 years and older with cystic fibrosis (CF) who have the G551D-CFTR mutation on at least 1 allele.


Options:
A: Inclusion Criteria:

* Participants from Study 110 or Study 111 entering the ivacaftor arm must have completed the assigned study drug treatment duration in the previous study.
* Participants from Study 113 entering the ivacaftor arm must have completed all study related treatments through the Follow-up Visit and met the Study 113 responder criteria during the previous study.
* Participants entering the observational arm must have completed at least 4 weeks of study drug treatment in their previous study (Study 110 or Study 111), must have completed the previous study but do not wish to enroll in the ivacaftor arm, or must have completed the previous study but do not meet the inclusion criteria of the ivacaftor arm.
* Participants of childbearing potential entering the ivacaftor arm must not be pregnant.
* Participants entering the ivacaftor arm must be willing to comply with contraception requirements.

Exclusion Criteria (Ivacaftor Arm Only):

* History of any illness or condition that might confound the results of the study or pose an additional risk in administering ivacaftor to the Participant.
* Use of moderate or strong inhibitors or inducers of cytochrome P450 (CYP) 3A.
* Evidence of cataract or lens opacity at or before the Day 1 Visit.
B: Inclusion Criteria:

* Signed informed consent available before any study specific tests or procedures are performed
* Patients must be at least 18 years of age at time of inclusion (i.e. upon signature of informed consent)
* Patient diagnosed with Cystic Fibrosis according to standard criteria (i.e. either elevated sweat chloride content above 60 mmol/ L and/ or genetic testing)
* Patient is homozygous for the deltaF508 mutation
* Patient has a mild-to-moderate stage of lung disease as determined by FEV1 (FEV1 between 40 and 100% predicted)
* Patient has a stable condition of lung disease (no ongoing or recent pulmonary exacerbation and no change in current treatment) within the last 4 weeks prior to screening
* Ability and willingness to understand and follow study procedures for the entire study
* Patients do not smoke. Patients with a history of smoking can be included, if they have refrained from smoking for the last 3 months. If a patients starts smoking during the study participation, he/ she needs to be excluded and considered to be a drop out
* Body mass index (BMI): ≥ 16 kg/ m² (calculated by dividing the patient's weight by the square of his/ her height \[kg/ m2\])

Inclusion criterion valid for study part 1 only:

- Women of childbearing potential must agree to use adequate contraception when sexually active. 'Adequate contraception' is defined as one highly effective form of contraception (intrauterine devices \[IUD\], contraceptive implants or tubal sterilization) or a combination of methods (hormone method with a barrier method ). If a partner's vasectomy is the chosen method of contraception or if a partner has documented azoospermia, a hormone or barrier method must be used in combination. Adequate contraception is required from the signing of the informed consent form up until 4 weeks after the last study drug administration

Inclusion criteria valid for study part 2 only:

* Women of childbearing potential must agree to use adequate contraception when sexually active. 'Adequate contraception' is defined as one highly effective form of contraception (intrauterine devices \[IUD\], contraceptive implants or tubal sterilization) or a combination of methods (hormone method with a barrier method). For patients on Orkambi hormonal methods (including hormonal oral contraceptives) cannot be accepted in this study. They need to choose non-hormonal methods. If a partner's vasectomy is the chosen method of contraception or if a partner has documented azoospermia, a hormone or barrier method must be used in combination. Adequate contraception is required from the signing of the informed consent form up until 4 weeks after the last study drug administration
* Patients receiving Orkambi (Lumcaftor + Ivacaftor) as part of their standard care need to be on stable Orkambi treatment for at least 3 months prior to screening (patients on Lumacaftor and/or Ivacaftor are excluded in part 1)

Exclusion Criteria:

* Patients with Cystic Fibrosis with any background other than homozygous deltaF508 mutation
* Exclusion criterion only valid for study part 1: Patients receiving treatment with Lumacaftor and/ or Ivacaftor
* Active state of hemoptysis or pulmonary hemorrhage, including those events managed by bronchial artery embolization. Also any history of moderate hemoptysis within the 3 months prior to inclusion
* Any history of pneumothorax, bronchial artery embolization or massive hemoptysis. Massive hemoptysis being defined as acute bleeding \>240 mL in a 24-hour period or recurrent bleeding \>100 mL/ d over several days
* A positive sputum culture for Burkholderia cenocepacia, Burkholderia dolosa, and/ or Mycobacterium abscessus either currently or within the previous year
* Active allergic broncho-pulmonary aspergillosis
* Current pulmonary exacerbation
* Known history of solid organ transplantation
* Known history of any form of pulmonary hypertension
* Clinically relevant deviations of the screened laboratory parameters from reference ranges outside of expected changes for Cystic Fibrosis patients, especially a hemoglobin value below 110 g/L or a creatinine clearance based on the Cockcroft-Gault formula \< 15 ml/ min
C: Inclusion Criteria:

* Confirmed diagnosis of CF with ∆F508-CFTR mutation in both alleles
* Forced expiratory volume in 1 second (FEV1) greater than or equal to (\>=) 40 percent (%) of predicted normal for age, gender, and height
* Weight \>=40 kilograms (kg) and body mass index greater than or equal to 18.5 kilogram per square meter (kg/m\^2)
* Screening laboratory values, tests, and physical examination within acceptable ranges
* Negative pregnancy test (for women of child-bearing potential)
* Able and willing to follow contraceptive requirements
* Willing to remain on a stable medication regimen for the duration of study participation

Exclusion Criteria:

* History of any illness, or any ongoing acute illness, that could impact the safety of the study participant or may confound results of study
* Pulmonary exacerbation or changes in therapy for pulmonary disease within 14 days before receiving the first dose of study drug
* Impaired hepatic or renal function
* History of organ or hematological transplant
D: Inclusion Criteria:

* Male or female subjects with confirmed diagnosis of CF
* Must have the G551D-CFTR mutation in at least 1 allele
* FEV1 \>90% of predicted normal for age, gender, and height

Exclusion Criteria:

* Ongoing participation in another therapeutic clinical study or prior participation in an investigational drug study within the 30 days prior to screening
* Use of inhaled hypertonic saline treatment within 2 weeks of the Period 1, Day 1 visit

Answer: D