This open-label, rollover study of orally administered VX-770 was conducted in participants with CF to evaluate the safety and efficacy of long-term VX-770 treatment. Participants who were previously enrolled in Study 102 (VX08-770-102/NCT00909532) and Study 103 (VX08-770-103/NCT00909727), and met certain criteria were eligible to enroll in this study (Study 105/VX08-770-105/NCT01117012).