Mycophenolate acid (MPA) has been developed and approved in combination with cyclosporine and has been used in kidney transplantation for more than a decade. At present, combination of tacrolimus and mycophenolate acid tends to be considered as the standard of care for maintenance immunosuppression in kidney transplantation. Mainly due to a different effect on the entero-hepatic recycling pathway, cyclosporine and tacrolimus differently interfere with MPA clearance. When used with tacrolimus, MPA dosage has thus to be adjusted and cannot be extrapolated from what is recommended for a cyclosporine-based treatment. However, there is currently no clear guideline for MPA dosing when this drug is used in combination with tacrolimus. This is potentially detrimental for patients since under-or overexposure of MPA has been clinically linked to the outcome of transplantation.

The purpose of this study is to pharmacologically validate an original MPA dosing regimen in combination with tacrolimus within the three months post-kidney transplant. This regimen consists in an intensified dosing of mycophenolate sodium during the earliest period of transplantation in order to rapidly reach the appropriate MPA blood exposure followed by a gradual decrease in dose in order to prevent MPA overexposure.

Inclusion Criteria:

• >18 years
• Renal transplant from a dead or alive donor.
• Patients treated by initial quadritherapy with basiliximab, tacrolimus, steroid et mycophenolate sodic
• ΒHCG pregnancy test negative at the initiation of Myfortic ®
• Effective contraception during treatment and up to 6 weeks after treatment with Myfortic ®

Exclusion Criteria:

• Patient at high risk of rejection of a transplant
• IMC > ou = 30
• Platelets < 75000 / mm3 and/or neutrophils < 1500 / mm3 and/or leukocytes < 2500/ mm3 and/or hemoglobin < 6 g/dL.
• Patient requiring a anti-CMV prophylaxis by valganciclovir.
• Pregnancy or breast feeding.