Initial Dosage Range of Tacrolimus by Genotyping in Chinese Renal Transplantation

Summary

Acute rejection (AR) is the main complication after transplantation, which is a severe risk of chronic rejection and implant devitalization.

Tacrolimus (FK506) is an immunosuppressant used for the prevention of episodes of acute rejection. Tacrolimus is characterized by a narrow therapeutic index and important interindividual variations of its pharmacokinetic characteristics.

Tacrolimus is metabolized through the liver by the cytochrome P450 system, the cytochrome P450 3A5 (CYP 3A5) isoenzyme specifically. Polymorphisms in the CYP 3A5 gene have been associated with changes in metabolic function of the translated isoenzyme. These polymorphisms result in metabolism acceleration of tacrolimus as compared to subjects having the wild type gene, consequently leading to insufficiency of tacrolimus; it is theorized that this leads to higher risk of acute rejection. Several retrospective studies suggested an association between a genetic polymorphism of CYP3A5 and the interindividual variations of tacrolimus blood concentration. In particular, our initial study showed that adult renal transplant recipients with the CYP3A5\*1/\*3 and \*1/\*1 （expressors） genotype require higher, fixed, starting dose compared with CYP3A5\*3/\*3 （nonexpressor）to reach the predefined target exposure early after transplantation.

This prospective study is designed to evaluate whether genetic testing of CYP 3A5 can improve tacrolimus initiation better than usual care. This study is a prospective, multicentric, open, parallel , efficacy study. 300 receivers of a renal transplant in 8 centres will be included.

The genotyping of gene CYP3A5 will be carried out in the 4-7days before renal transplantation. After transplantation, the patients will be treated by MMF, corticosteroids and tacrolimus at a dosage adapted to their genotype(0.15mg/kg/d for CYP3A5\*1/\*1 type and CYP3A5\*1/\*3 type，0.08mg/kg/d for CYP3A5\*3/\*3 type).

The determination of tacrolimus blood concentration will be carried out on Day 3,5,7,14,18,21,28,35,49,63,77,90. The daily amounts of tacrolimus could be modified if necessary to reach the desired blood concentrations. The total duration of the study for a patient is 3 months after transplantation.

The objective of this study is to determine the initial dosage of tacrolimus in Chinese renal transplantation patients by genotyping of the cytochrome P450 3A5

Conditions

• Renal Transplantation

Interventions

DRUG

Tacrolimus

The genotyping of gene CYP3A5 will be carried out in the 4-7days before renal transplantation. After transplantation, the patients will be treated by MMF, corticosteroids and tacrolimus at a dosage adapted to their genotype(CYP3A5\*1/\*1 type and CYP3A5\*1/\*3 type administer 0.15mg/kg/d，CYP3A5\*3/\*3 type administer 0.08mg/kg/d).

Sponsors & Collaborators

• Capital Medical University

  collaborator OTHER

• Shanghai Changzheng Hospital

  collaborator OTHER

• Pharmacology Research Institute

  collaborator OTHER

• Air Force General Hospital of the PLA

  collaborator OTHER_GOV

• Health Department of General Logistics

  collaborator UNKNOWN

• The Second Artillery General Hospital

  lead OTHER

Principal Investigators

• LIHong LIU, MD Ph.D · The Second Artillery Genaral Hospital

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2009-07-31

Primary Completion

2010-12-31

Completion

2011-06-30

Countries

• China

Study Locations