Mycophenolate sodium dosing in combination with tacrolimus: pharmacokinetic evaluation of a novel regimen in de novo tacrolimus-treated kidney transplant patients.

BACKGROUND: There are no clear guidelines concerning the appropriate dose of mycophenolate acid (MPA) to be used in association with tacrolimus. When MPA is given at an approved fixed dose in cyclosporine-treated patients, initial systemic under exposure is frequent and associated with the occurrence of acute rejection. We pharmacologically evaluated in tacrolimus-treated recipients a novel dosing regimen of MPA with an initial high dose followed by a gradual decrease over time.

METHODS: 15 de novo tacrolimus-treated kidney transplant patients were administered mycophenolate sodium at the dose of 720 mg b.i.d. for the first week post-transplant, 540 mg b.i.d. until Day 30, and then 360 mg b.i.d. until Day 90. MPA exposure was evaluated by the 12 h area under MPA concentration versus time curve (AUC) determined at Days 2, 7, 15, 30 and 90 post-transplant.

RESULTS: Median MPA AUC was constantly within the therapeutic window of 30 - 60 mg/l × h throughout the three months of evaluation. More than 75% of patients had a MPA AUC above 30 mg/l × h at Day 2 and Day 7 post-transplant.

CONCLUSION: This exploratory study suggests that such a dosing regimen of mycophenolate sodium might quickly offer and sustain an optimal exposure to MPA in tacrolimus-treated kidney transplant patients.