Equivalent pharmacokinetics of mycophenolate mofetil in African-American and Caucasian male and female stable renal allograft recipients

African-American (AA) renal transplant recipients require higher doses of mycophenolate mofetil (MMF) than Caucasians. A hypothesized pharmacokinetic (PK) difference Was tested in stable renal transplant recipients. Whole blood was collected before, and 20,40 and 75 min, and 2,3,4,6,8 and 12 h after the MMF dose. Mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) were analyzed using HPLC. Analysis of variance was performed for the primary end-points of dose-adjusted PK parameters AUC(0-12) and C-max of MPA using log-transformed values. Differences between races and genders were estimated: 90% confidence intervals (Cl) were calculated. Back-transformation gave estimates of the race and gender ratio and their Cl. Equivalence of the groups was determined if the 90% confidence limits were included in the interval (0.80, 1.25). The calculated PK parameters were comparable among the four subgroups (Caucasian, AA, Male, Female). The 90% Cls for the ratio of dose-adjusted AUC(0-12) of MPA between races were between 89.7 and 112.9%. There were no race, gender or race-by-gender effects (P-values = 0.196) nor differences between diabetics and nondiabetics. This study demonstrates that dosing requirement for MMF in AA and Caucasians is unlikely to be related to different exposures to MPA.