Please assess the completion status of the following clinical trial:

Trial Title: Study of the Effect of Ivacaftor on Lung Clearance Index in Subjects With Cystic Fibrosis and the G551D Mutation

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: CROSSOVER
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: QUADRUPLE
- Phase: PHASE2
- Number of Arms: 2.0

Eligibility Criteria:
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

- Gender: ALL
- Minimum Age: 6 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- Treatment Sequence 1 (Type: EXPERIMENTAL): Ivacaftor administered in Treatment Period 1 and placebo administered in Treatment Period 2.
- Treatment Sequence 2 (Type: EXPERIMENTAL): Placebo administered in Treatment Period 1 and ivacaftor administered in Treatment Sequence 2.

Based on this trial design, predict the completion outcome and termination type (if applicable).