Evaluation of VX-828 in Healthy Participants and in Participants With Cystic Fibrosis

Key Inclusion Criteria:

Parts A-D:

* Participants between the ages of 18 and 55 years
* Body mass index (BMI) of 18.0 to 32.0 kilogram per meter square (kg/m\^2)
* A total body weight of more than (\>) 50 kg
* Nonsmoker or ex-smoker for at least 3 months before screening with current nonsmoking status confirmed by urine or blood cotinine at screening
* Cohort C2 only: Willing to provide a single DNA sample

Part E:

* Participants 18 years or older
* Confirmed diagnosis of CF as determined by the investigator
* A total body weight of more than or equal to (\>=) 35 kg
* Participants must be heterozygous for F508del with a second CFTR allele carrying a minimal function mutation that is not responsive to ELX/TEZ/IVA therapy
* Participants must have a forced expiratory volume in 1 second (FEV1) of greater than or equal to (≥) 40% of predicted normal for age, sex, and height

Key Exclusion Criteria:

Parts A-D:

* History of febrile illness or other acute illness within 14 days before the first dose of study drug
* Any condition possibly affecting drug absorption

Part E:

* An acute illness not related to CF (e.g., gastroenteritis) within 14 days before the first dose of study drug
* History of solid organ or hematological transplantation
* History of clinically significant cirrhosis with or without portal hypertension
* Lung infection with organisms associated with a more rapid decline in pulmonary status

Other protocol defined Inclusion/Exclusion criteria will apply.