Belatacept in Heart Transplantation

This is a phase 2, prospective, multi-center, open-label clinical trial. Sixty-six (66) primary heart transplant recipients will be randomized (1:2) to receive either standard-of-care, tacrolimus-based immunosuppression, or a belatacept-based regimen with gradual tacrolimus withdrawal over 9-months post-transplant. Both study arms will receive CellCept® (mycophenolate mofetil- MMF) or Myfortic® (mycophenolate sodium). Corticosteroids will be continued throughout the study in the belatacept arm. The primary objective is to evaluate whether NULOJIX® (belatacept), when implemented with gradual tacrolimus withdrawal over 9 months, is safe with respect to preventing the composite endpoint of acute cellular rejection (ACR) \>= International Society of Heart and Lung Transplantation (ISHLT) 2R, hemodynamic compromise rejection in the absence of a biopsy or histological rejection, re-transplantation, and death at 18 months post-transplant.

Inclusion Criteria: Study entry 1. Subject must be able to understand the purpose of the study and be willing to participate and provide written consent 2. Recipient of a primary heart transplant (heart transplant only) 3. Epstein-Barr Virus (EBV) seropositive (VCA IgG, EBNA IgG). If EBNA is not available, enrollment may proceed but the result must be available prior to randomization. 4. Agreement to use contraception; according to the Food and Drug Administration (FDA) Office of Women's Health (http://www.fda.gov/birthcontrol), there are a number of birth control methods that are more than 80% effective. Female participants of child-bearing potential must consult with their physician and determine the most suitable method(s) from this list to be used for the duration of the study 5. In the absence of a contraindication, vaccinations must be up to date per the Division of Allergy, Immunology, and Transplantation (DAIT) Vaccination Guidance for Patients in Transplant Trials (niaidtransplantstudies.org) 6. Mechanical support or investigational drug trials where the intervention ends at the time of transplantation are permitted. Randomization 1. Recipient of a primary heart transplant 2. No desensitization therapy prior to transplant 3. Negative crossmatch actual or virtual, on the most recent sera as determined by the participating study center 4. Female subjects of childbearing potential must have a negative pregnancy test (serum or urine) prior to randomization 5. Agreement to use contraception; according to the FDA Office of Women's Health (http://www.fda.gov/birthcontrol), there are a number of birth control methods that are more than 80% effective. Female participants of child-bearing potential must consult with their physician and determine the most suitable method(s) from this list to be used for the duration of the study. Those who choose oral contraception must agree to use a second form of contraception after administration of study drug for a period of 1 year after the last dose of study drug 6. Pre-transplant eGFR (CKD-epi) \>30ml/min/1.73m\^2. If eGFR \