The vasopressin V2 receptor antagonist tolvaptan has been recently shown to delay the increase in total kidney volume (TKV) as well as decline in kidney functions compared with placebo in a randomized controlled trial (RCT) of patients with ADPKD with near-normal kidney functions and late-stage ADPKD2,3. Here, AVPR2 is linked to autosomal dominant polycystic kidney disease.