The efficacy of interruption of the renin-angiotensin-aldosterone system (RAAS) on the progression of cystic disease and on the decline in renal function in autosomal dominant kidney disease (ADPKD) will be assessed in two simultaneous multicenter randomized clinical trials targeting different levels of kidney function: 1) early disease defined by GFR >60 mL/min/1.73 m2 (Study A); and 2) moderately advanced disease defined by GFR 25-60 mL/min/1.73 m2 (Study B). Participants will be recruited and enrolled, either to Study A or B, over the first three years. Participants enrolled in Study B will be followed for five-to-eight years, with the average length of follow-up being six and a half years.