Mycophenolic acid trough level measurements and clinical outcomes in kidney transplantation recipients on a fixed dose (1.5 g/d) of mycophenolate mofetil in Korea

Abstract

Background: Mycophenolate mofetil (MMF) is routinely used at a fixed dose, but several factors interact to alter the blood level of mycophenolic acid (MPA), resulting in toxicity or treatment failure.

Methods: From January 2007 to December 2008, 85 kidney transplantation patients were given a fixed dose of 1.5 g/d of MMF in 12-hour intervals. MPA trough levels were measured on postoperative 1 week, 1 month, 3 months, 6 months, and 12 months.

Results: Mean age of patients was 41 years. Thirty five cases were deceased donor kidney transplantations and 50 were living donor kidney transplantations. Mean trough levels of MPA were 1.04 microg/mL, 1.09 microg/mL, 1.28 microg/mL, 1.83 microg/mL, and 1.69 microg/mL at postoperative 1 week, 1 month, 3 months, 6 months, and 12 months, respectively. Mean trough levels of the subgroup of patients taking cyclosporine were 0.82 microg/mL, 0.94 microg/mL, 1.01 microg/mL, 1.56 microg/mL, and 1.46 microg/mL (n=36). Mean trough levels of the subgroup of patients taking tacrolimus were 1.19 microg/mL, 1.21 microg/mL, 1.56 microg/mL, 2.13 microg/mL, and 2.20 microg/mL (n=49). At 12 months, 31% of all patients experienced one or more opportunistic infections. Eight patients (9.4%) had cytomegalovirus infections, 14 patients (16.5%) had polyomavirus infections, and four patients (4.7%) had parvovirus infections. Ten patients (11.8%) experienced biopsy-proven acute rejection during the follow-up period.

Conclusion: Mean MPA trough levels of patients on 1.5 g/d of MMF reached 1.0 microg/mL within 1 week. Thirty one percent of patients experienced opportunistic infections, and 11.8% of patients had biopsy-proven acute rejections.