Effect of 3g Versus 2 g MMF in Combination With Tacrolimus on Progression of Renal Allograft Interstitial Fibrosis

Development of chronic changes (scarring) in transplanted kidney tissue is a major cause of long-term kidney function deterioration and ultimately graft loss. It results from both immunologic and non-immunologic mechanisms. Mycophenolate mofetil (MMF) is immunosuppressive drug used for prevention of rejection after kidney transplant, usually in combination with a calcineurin inhibitor (tacrolimus or cyclosporine), with or without corticosteroids. Besides immunosuppression, MMF may also have direct antifibrotic properties. Tacrolimus has potent immunosuppressive effects and is the cornerstone of contemporary posttransplant immunosuppressive therapy in kidney recipients. However, it is also nephrotoxic. The hypothesis of the present study is that in the setting of similar net immunosuppression, higher dose of MMF (3 g daily) will result in slower progression of kidney fibrosis during first year posttransplant as compared to MMF 2 g daily. To test this hypothesis, the present study will randomly assign low immunological risk kidney transplant recipients to either 2g or 3 g MMF daily, in combination with tacrolimus, with, or without maintenance steroids. All patients will have kidney biopsy at implantation and at 12 months after transplantation. Main outcome will be 1-year change in chronic kidney histology (interstitial fibrosis) assessed by protocol biopsy.