Inclusion Criteria:  Male or female ≥ 18 years of age Recipient of their first kidney transplant from a living or deceased donor  Exclusion Criteria:  Induction therapy, other than study assigned rATG, planned as part of initial immunosuppressive regimen Currently treated with any systemic immunosuppressive regimen, including immunologic biologic therapies, with the exception of 5 mg prednisone or equivalent daily; Previous treatment with AT 1501 or any other anti CD40LG therapy The patient has previously received a bone marrow transplant or any other solid organ transplant, including a kidney, or will be undergoing a multi organ or dual kidney transplant Will receive a kidney with an anticipated cold ischemia time of > 30 hours;  Will receive a kidney from a donor that meets any of the following:  • Donation after Cardiac Death (DCD) criteria; or  Extended Criteria Donor (ECD) criteria, defined as:  Is blood group (ABO) incompatible; or Age ≥ 60 years; or Age 50-59 years with any 2 of the following criteria Death due to cerebrovascular accident History of hypertension Terminal creatinine ≥ 133 μmol/L Human leukocyte antigen identical (two haplotype match or zero HLA mismatch) donor Medical conditions that require chronic use of systemic steroids at a dose higher than 5 mg prednisone or equivalent per day  History of a TE event, known hypercoagulable state, or condition requiring long term anticoagulation:  Patients with a history of clotted venous access not requiring long term anticoagulation may be included at the Investigator's discretion if have no other history of TE events or known hypercoagulable state