Kidney damage is a major complication of current antirejection medicines used in transplantation. An increasing number of brittle diabetics are successfully receiving a pancreas transplant. One of the challenges following pancreas transplant is that a patient can develop kidney damage from one of their antirejection medicines, tacrolimus. The objective of this study is to substitute a new antirejection medicine which does not cause kidney damage, belatacept for tacrolimus in patients that have developed signs of tacrolimus related kidney damage to slow the progression of kidney disease.

Nephrotoxicity is a major complication of current immunosuppression regimens used in transplantation. Pancreas transplantation has been increasedly performed to manage labile diabetes mellitus during the last few decades and survival rates of pancreatic grafts are improving. One of the challenges that is faced following pancreas transplantation alone are pathologic changes from diabetes frequently seen in native kidneys in the pancreas transplant recipients. High levels of calcineurin inhibitors (CNI) have been identified as risk factors for decline in kidney function and progression to end-stage renal disease. The objective of this trial is to take subjects who have biopsy proven CNI toxicity off of their CNI and begin belatacept, which is not a CNI.

The hypothesis is by switching the pancreas transplant subject with documented CNI kidney toxicity to belatacept will slow the progression of chronic kidney disease.

Inclusion Criteria:

• Pancreas transplant alone recipients
• EBV IgG positive
• Biopsy proven calcineurin inhibitor toxicity on native kidney biopsy
• Maintained on a regimen of tacrolimus, sirolimus, mycophenolate

Exclusion Criteria:

• EBV IgG negative
• Not maintained on an immunosuppression regimen that contains tacrolimus
• Unable or unwilling to give informed consent
• Active infection
• History of malignancy post transplant
• Glomerular filtration rate < 15 mL/min