title: Influence of different allelic variants of the CYP3A and ABCB1 genes on the tacrolimus pharmacokinetic profile of Chinese renal transplant recipients.
abstract: Tacrolimus has a narrow therapeutic window and a wide interindividual variation in its pharmacokinetics. The cytochrome P450 3A (CYP3A) and the ATP-binding cassette B1 (ABCB1) genes play an important role in the tacrolimus disposition. Therefore, the aim of this study was to evaluate whether CYP3A and ABCB1 polymorphisms are associated with the area under the time concentration curve (AUC0-12) calculated using a two time point sample strategy. The CYP3A and ABCB1 genotypes were determined by real-time polymerase chain reaction (RT-PCR) fluorescence resonance energy transfer (FRET) assays in 103 Chinese renal transplant recipients and consequently related to their dose-normalized (dn)AUC0-12. A significant allele-dependent effect (Kruskal-Wallis; p < 0.001) was observed between the CYP3A5*3 polymorphism and the dnAUC0-12. Multiple regression analysis showed that the CYP3A5*3 polymorphism is the most significant independent variable and explained 35% of the dose requirement variability in relation to tacrolimus use. Regarding the ABCB1 G2677T/A and C3435T polymorphisms, a trend was observed between the different genotypes and the dnAUC0-12. In conclusion, the CYP3A5*3 polymorphism may be an important factor in determining the dose requirement for tacrolimus and genotyping can help determine the initial daily dose required by individual patients for adequate immunosuppression.
authors.affiliation: Queen Elizabeth Hospital, Renal Unit, Department of Medicine, 30 Gascoigne Road, Kowloon, Hong Kong. ccyz01@hotmail.com
authors.forename: Chi Yuen
authors.initials: CY
authors.lastname: Cheung
authors.forename: Robert A M
authors.initials: RA
authors.lastname: Op den Buijsch
authors.forename: Kim Ming
authors.initials: KM
authors.lastname: Wong
authors.forename: Hoi Wong
authors.initials: HW
authors.lastname: Chan
authors.forename: Ka Foon
authors.initials: KF
authors.lastname: Chau
authors.forename: Chun Sang
authors.initials: CS
authors.lastname: Li
authors.forename: Kay Tai
authors.initials: KT
authors.lastname: Leung
authors.forename: Tze Hoi
authors.initials: TH
authors.lastname: Kwan
authors.forename: Johan E
authors.initials: JE
authors.lastname: de Vrie
authors.forename: Petal Ahm
authors.initials: PA
authors.lastname: Wijnen
authors.forename: Marja P
authors.initials: MP
authors.lastname: van Dieijen-Visser
authors.forename: Otto
authors.initials: O
authors.lastname: Bekers
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D004247:DNA / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D019450:Genes, MDR; D014644:Genetic Variation; D006723:Hong Kong; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D010597:Pharmacogenetics; D016559:Tacrolimus / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D007166:Immunosuppressive Agents; D004247:DNA; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; C510164:CYP3A5 protein, human; D051544:Cytochrome P-450 CYP3A; D016559:Tacrolimus