Conversion of azathioprine to mycophenolate mofetil and chronic graft failure progression

The purpose of the study was to evaluate the impact of conversion from azathioprine (AZA) to mycophenolate mofetil (MMF) on graft function in 35 renal transplant recipients with chronic allograft nephropathy (CAN). The immunosuppressive regimen originally consisted of AZA, cyclosporine (CsA), and prednisone (Pr). At the onset of the study (mean period = 39 posttransplant months), a graft biopsy was performed on all patients who were randomly divided into group 1 (n = 17) in whom MMF was introduced instead of AZA. The remaining 18 subjects (group 2) were maintained on the previous regimen. Two periods were analyzed: period I: 12 months before, and period II: 12 months after biopsy and therapy conversion. Graft function was assessed monthly by measurements of the 24-hour creatinine clearance (CCr). Analysis of variance (ANOVA) was used to compare the differences in CCr and proteinuria between the two groups. No difference was observed in the baseline characteristics, in the incidence of delayed graft function and acute rejection, or in the mean CsA dose. Pathohistological analysis revealed advanced CAN in the majority of patients in both groups. The morphological changes negatively correlated with graft function. The graft function showed parallel deterioration in the two groups; no significant difference was observed in the mean CCr values in the periods studied. Proteinuria was similar for both groups throughout the study. Conversion of AZA to MMF in recipients with CAN, albeit safe, was without significant benefit on the progression of chronic graft failure over the period of a year.