Kidney graft recipients receiving a firs kidney graft (between 6 months and 5 years post-transplantation) will be randomized 1:1 to receive an everolimus based immunosuppression (in association with steroids and mycophenolate mofetil) or to continue their calcineurin inhibitor-based immunosuppression regimen. The primary objective will be the reduction of total native kidney volume after a 2-years treatment period.