A Study to Evaluate the Benefits and Risks of Conversion of Existing Adolescent Kidney Transplant Recipients Aged 12 to <18 Years to a Belatacept-based Immunosuppressive Regimen as Compared to Continuation of a Calcineurin Inhibitor-based Regimen, and Their Adherence to Immunosuppressive Medications

Inclusion Criteria:

1. Male and female adolescents 12 to less than 18 years of age
2. Recipients of a renal allograft from a living or deceased donor transplanted at least 6 calendar months prior to enrollment
3. Receiving a stable regimen of a calcineurin inhibitor (CNI), with mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium/mycophenolate mofetil (EC-MPS/MPA), with or without daily corticosteroids for ≥ 30 days prior to randomization
4. Clinically stable renal function during the 12-week period prior to screening, in the opinion of the investigator and based on protocol-defined criteria for proteinuria and estimated glomerular filtration rate (eGFR)
5. Serologic evidence of past exposure to Epstein-Barr virus (EBV) and current absence of EBV DNA replication at or prior to renal transplantation and during the Screening period
6. Completion of an initial course of SARS-CoV-2 vaccination per local standard of care, a minimum of 6 weeks prior to enrollment

Exclusion Criteria:

1. Recipients with EBV serostatus negative or unknown at screening or at transplant
2. Treatment for biopsy-proven acute rejection (BPAR) of any degree of severity within 6 calendar months prior to enrollment
3. Biopsy-confirmed antibody-mediated acute rejection at any time with the current allograft
4. Banff 97 grade IIA or higher acute cellular rejection (or equivalent), or treatment with plasmapheresis or rituximab for any acute rejection at any time with the current allograft
5. Current evidence or past history of active or inadequately treated latent tuberculosis (TB) infection
6. Previously treated with belatacept or previously enrolled in a belatacept trial with their present allograft

Other inclusion/exclusion criteria apply