Aim The general aim of this study is to assess the efficacy and safety of 6 month treatment with sirolimus (on the top of the best available therapy) as compared to conventional therapy in adult patients with ADPKD and normal renal function or mild to moderate renal insufficiency. In particular we will compare the change over baseline of the total kidney volume volume in sirolimus and conventional treatment ADPKD groups during 6 month follow-up.