Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disorder with a risk of significant morbidity, including kidney failure. The prognosis of the disease may differ between individuals, although loss of kidney function over time is inevitable. The quest for a treatment to slow down the loss of kidney function and progression to kidney failure has spanned decades. Three large phase 3 clinical trials—TEMPO 3:4 (Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and Its Outcomes 3:4 Trial),1 TEMPO 4:4,2 and REPRISE (Replicating Evidence of Preserved Renal Function: an Investigation of Tolvaptan Safety and Efficacy in ADPKD)3—showed that tolvaptan decreased rate of kidney growth and kidney function loss.