Could polycystic kidney disease be cured?

Not cured. Other than by kidney transplant. Polycystic kidney disease is not universally fatal. Impaired kidney function can be controlled for a long time by diet ; control of hypertension if present. Occasionally symptomatic cysts can be marsupialised laparoscopically. But, as yet, there is no medical treatment to eliminate the cysts. Many require eventual dialysis or transplant.