The PROMISE Pediatric Study 6 to 11 Years Old

This is a prospective, multi-center observational study. The study is designed to measure the clinical effectiveness of elexacaftor, tezacaftor and ivacaftor (ETI) triple combination therapy in children (6-11 years of old) with one or more copies of the F508del mutation, study the effects of ETI across a number of CF disease manifestations, and collect specimens for future research. Subjects in the study will have one "before ETI" visit within 30 days before initiation of the therapy and five "after ETI" visits over a 24-month follow-up period. Participants who have participated in the original PROMISE Pediatric Sub-Study have the option of participating in a long-term extension with annual visits performed at the 36- and 48-month timepoints. The durability of the clinical and biological changes in the PROMISE Pediatric Sub-Study can be assessed with extended follow-up, which would enable the sub-studies to consider potential clinical consequences of the biological or physiological effects being studied. This work will help to inform long term prognosis and feasibility of certain clinical trials outcomes for interventional studies and may be useful when considering research priorities in drug development. The duration of participation for each subject is 24 months (with an additional 24 months if participants agree to the optional long-term extension). NOTE: FDA has granted approval for elexacaftor, tezacaftor and ivacaftor in the 6-11 age group.