GSK-4771261

This is a study where a new drug, called GSK4771261 is being tested. Neither the study doctors, study staff or participants will be aware of what treatment is being given. Part A is testing the new study treatment on healthy people. This is to see if it's safe, what it does to the body, and how the body's defense system responds to it. Part B is similar, but the study treatment will be given to people who have a kidney disease called autosomal dominant polycystic kidney disease (ADPKD).