Mycophenolate mofetil maintenance therapy in renal transplant patients: long-term results of the TranCept STAY study.

Background: This prospective observational study documented long-term renal function in transplant recipients receiving mycophenolate mofetil (MMF). Methods: Kidney allograft recipients >6 months post-transplantation, with a glomerular filtration rate (GFR) >20 mL/min, receiving MMF from time of transplantation were enrolled and followed for four yr. Subgroups were identified based on time between transplantation and enrollment: Y < 1 (6 months-1 yr); Y1-2 (> 1-2 yr); Y2-5 (>2-5 yr) and Y > 5 (> 5 yr). Results: A total of 2040 patients were analyzed; 780, 410, 541 and 309 in subgroups Y < 1, Y1-2, Y2-5 and Y > 5. For all patients combined GFR decreased during the observational period by approximately 1 mL/min/yr (median GFR (mL/min) was 50.8, 50.5, 48.7, and 47.6 at one, two, three, and four yr). Survival estimates for decline in renal function (>20% GFR decline at one time point) were 78%, 66%, 57%, and 51% at one, two, three and four yr, with no significant differences between subgroups (p > 0.05). In adult patients, higher doses of MMF (>= 1 g/d) were associated with better GFR outcomes (median GFR (mL/min) 48.1 vs. 39.9 at four yr post-enrollment; p = 0.0037). When comparing the effects of MMF combined with calcineurin inhibitors (CNIs), GFR was increased with lower doses of tacrolimus or cyclosporin. There were no major tolerability or acute rejection problems and graft survival was similar in all subgroups (graft survival estimates for all patients combined were 99%, 95%, 92%, and 90% at one, two, three, and four yr). Conclusions: Long-term MMF immunosuppression preserves renal function and higher MMF doses combined with lower CNI doses may provide better patient outcomes.