Study to Evaluate Adverse Events and Change in Disease Activity With Oral Capsules of Galicaftor/Navocaftor/ABBV-119 or Galicaftor/Navocaftor/ABBV-576 Combination Therapies in Adult Participants With Cystic Fibrosis

Cystic Fibrosis (CF) is a rare, life-threatening, genetic disease that affects the lungs and digestive system, significantly impairing the quality of life, with those affected having a median age of death at 40. The main objective of this study is to assess how safe and effective is the combination therapy of galicaftor/navocaftor/ABBV-119 or Galicaftor/Navocaftor/ABBV-576 in adult participants with CF who are homozygous or heterozygous for the F508del mutation in each arm.

Galicaftor/Navocaftor/ABBV-119 combination therapy and Galicaftor/Navocaftor/ABBV-576 is being developed as an investigational drug for the treatment of CF. Study doctors place participants in 1 of the 4 groups, called treatment arms. Each group receives a different treatment. Around 90 adult participants with a diagnosis of CF will be enrolled in the study around approximately 35 sites worldwide.

Participants in arm 1 will receive oral capsules of galicaftor/navocaftor dual combination for 28 days followed by galicaftor/navocaftor/ABBV-119 triple combination for 28 days. Participants in arms 2 and 3 will receive the galicaftor/navocaftor/ABBV-119 triple combination or placebo for 28 days. Participants in arm 4 will receive galicaftor/navocaftor/ABBV-576 triple combination therapy for 28 days. For all study arms, ABBV-576, galicaftor, navocaftor, will be given once daily and ABBV-119 twice a day.

There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic. The effect of the treatment will be checked by medical assessments, blood tests, checking for side effects and completing questionnaires.

Participants in Cohorts 1 and 3 will receive Open-label therapy. Participants in Cohorts 2 will receive Double-blinded therapy.

Eligibility Criteria:
Inclusion Criteria:

* Confirmed clinical diagnosis of cystic fibrosis (CF).
* Arm 1 participants with genotype homozygous for the F508del CF transmembrane conductance regulator (CFTR) mutation and not receiving elexacaftor/tezacaftor/ivacaftor (ETI) treatment .
* Arm 2 and 3 participants with genotype heterozygous for the F508del CFTR mutation and a minimal function mutation and not receiving ETI treatment.
* Arm 4 participants with genotype either homozygous or heterozygous for the F508del mutation. Participants must be receiving stable ETI treatment.
* Percent predicted forced expiratory volume in 1 second (ppFEV1) \>= 40% and \<=90% of predicted normal for age, gender and height at screening.
* For arms 1 and 2: sweat chloride (SwCl) \>= 60 mmol/L at screening. For participants who participated in Study M19-530, it is acceptable to use a SwCl value that the central lab provided in Study M19-530 to establish eligibility.
* Weight \>= 35 kg at screening and Day -28 for arm 1 or day 1 for arms 2 to 4.

Exclusion Criteria:

- Clinically significant laboratory values at screening that would pose undue risk for the participant or interfere with safety assessments (per the investigator).