Introduction of mycophenolate mofetil and cyclosporin reduction in children with chronic transplant nephropathy.

Chronic transplant nephropathy (CTN) is the most important cause of kidney graft dysfunction. Studies in adult populations have reported a beneficial effect of non-nephrotoxic mycophenolate mofetil (MMF) on graft function in this setting. However, few studies were reported in children in this setting. We therefore reviewed the charts/ medical records of renal transplanted patients <18 yr of age at a single center who had switched from azathioprine to MMF as a result of progressive loss in graft function, for which vascular, infectious, and urological causes were excluded. Serum creatinine (SCr) and calculated creatinine clearance were compared prior to and after MMF introduction. Thirteen patients (nine male/four female), followed-up for 59.3+/-35.4 months after transplantation. were analyzed. Age at MMF introduction was 14.2+/-3.6 yr. In 11 patients a previous biopsy had shown features of CTN and four patients also presented signs of chronic cyclosporin A (CsA) nephrotoxicity. MMF was started at a dose of 1211 +/- 351 mg/day, and the CsA dose was decreased from 6.69 +/- 3.15 mg/ kg/day 6 months before MMF to 4.8+/-2.3 mg/kg/day at the time of MMF introduction. CsA was withdrawn in four patients. The median (25-75%) SCr value increased from 1.60 mg/dL (range 1.3 to 1.87 mg/ dL)6 months before MMF to 2.2 mg/dL (range 1.87-2.32 mg/dL) when MMF was introduced. Six months after introduction of MMF, the SCr level had decreased to 1.5 mg/dL (range 1.2-1.8 mg/dL) and remained stable until the last follow-up (17.5+/-9.2 months after MMF was started). A similar pattern occured with calculated SCr clearance. There were no acute rejections after changes in immunosuppression. The safety of MMF was also analyzed and in only one patient was the drug stopped as a result of intractable diarrhea. These findings suggest that MMF is sufficiently powerful to allow a decrease/withdrawal of CsA without the burden of acute rejection in a pediatric population with CTN.