This study investigates the safety and effects of a combination of investigational medications in young children with Cystic Fibrosis, a genetic disorder that affects the lungs and digestive system. The purpose of this study is to evaluate how these medications are processed in the body of children aged 1 to less than 2 years, who have a specific genetic makeup known as homozygous for F508del.

Participants in the study will undergo various procedures to assess the effects and safety of the investigational medications. These procedures may include regular health check-ups, laboratory tests, and monitoring of any side effects to ensure the well-being of the participants.

• Who can participate: Children who are 1 to less than 2 years old with Cystic Fibrosis and have the F508del mutation can participate. Participants must meet specific weight requirements and should not have significant health issues that could affect the study results.
• Study details: Participants will receive the investigational medications and be monitored for safety and effectiveness. A placebo, which is an inactive substance that looks like the investigational medication but does not contain any medicine, will not be used in this study.