This study is a randomized, multicenter, open-label, active control study to evaluate the safety and efficacy of AT-1501 compared with tacrolimus in the prevention of rejection in patients undergoing kidney transplantation. Up to 120 de novo kidney transplant recipients will receive rATG induction with corticosteroids (CS), and mycophenolate as maintenance therapy, and will be randomized 1:1 to receive either AT-1501 or tacrolimus.