CYP3A-status is associated with blood concentration and dose-requirement of tacrolimus in heart transplant recipients

Abstract

High inter-individual variability in tacrolimus clearance is attributed to genetic polymorphisms of CYP3A enzymes. However, due to CYP3A phenoconversion induced by non-genetic factors, continuous changes in tacrolimus-metabolizing capacity entail frequent dose-refinement for optimal immunosuppression. In heart transplant recipients, the contribution of patients’ CYP3A-status (CYP3A5 genotype and CYP3A4 expression) to tacrolimus blood concentration and dose-requirement was evaluated in the early and late post-operative period. In low CYP3A4 expressers carrying CYP3A5*3/*3, the dose-corrected tacrolimus level was significantly higher than in normal CYP3A4 expressers or in those with CYP3A5*1. Modification of the initial tacrolimus dose was required for all patients: dose reduction by 20% for low CYP3A4 expressers, a 40% increase for normal expressers and a 2.4-fold increase for CYP3A5*1 carriers. The perioperative high-dose corticosteroid therapy was assumed to ameliorate the low initial tacrolimus-metabolizing capacity during the first month. The fluctuation of CYP3A4 expression and tacrolimus blood concentration (C0/D) was found to be associated with tapering and cessation of corticosteroid in CYP3A5 non-expressers, but not in those carrying CYP3A5*1. Although monitoring of tacrolimus blood concentration cannot be omitted, assaying recipients’ CYP3A-status can guide optimization of the initial tacrolimus dose, and can facilitate personalized tacrolimus therapy during steroid withdrawal in the late post-operative period.

External assessment and refinement of a population pharmacokinetic model to guide tacrolimus dosing in pediatric heart transplant

“…Indeed, the CYP3A5*1 allele associated with extensive CYP3A5 metabolism has been shown to occur more frequently in individuals of black race, whereas the inactive CYP3A5*3 is the predominant allele in the white population 22,23 . Genetic differences in CYP3A5 have previously been shown to greatly alter the required therapeutic tacrolimus dose in both children and adults 24–27 . Interestingly, in the absence of CYP3A5 genotype data due to the retrospective nature of the current study, the impact of race was observed to decrease, rather than increase, the elimination of tacrolimus in the current study population.…”

Calcineurin Inhibitors Synergize with Manogepix to Kill Diverse Human Fungal Pathogens

“…In considering the implementation of such an approach, it will be essential to assess potentially problematic drug-drug interaction that could alter the pharmacology of FK506 and/or MGX. The CYP3A P450 sub-family is primarily responsible for FK506 metabolism [ 57 ]. Studies are ongoing in regards to the metabolism of fosmanogepix, but trials to date have not found significant MGX CYP3A4 inhibition.…”

Rapid clearance of tacrolimus blood concentration triggered by variant pharmacogenes

“…According to up‐to‐date knowledge, TAC bioavailability is considerably impacted by hepatic and intestinal CYP3A‐dependent metabolism that is altered by CYP3A genetic variants. Therefore, CYP3A4 and CYP3A5 single‐nucleotide polymorphisms (SNPs) are suggested to notably cause TAC clearance interindividual variability 6 . Seven years ago, based on published evidence supporting this relationship, the CPIC published guidelines for the CYP3A5 genotype and tacrolimus dosing as the CYP3A5*3 variant allele (rs776746) results in non‐functional CYP3A5 enzymes 7 …”

“…A single published meta‐analysis concluded that the CYP3A4*1B variant has an effect on TAC dosing in adult kidney transplant patients 9 . An important pharmacogenetic aspect is the possible linkage disequilibrium (LD) of CYP3A4*1B with CYP3A5*1 , which may lead to undifferentiated impact and the rapid clearance of TAC 6,8,9 …”

“…9 An important pharmacogenetic aspect is the possible linkage disequilibrium (LD) of CYP3A4*1B with CYP3A5*1, which may lead to undifferentiated impact and the rapid clearance of TAC. 6,8,9 This case report describes type IB acute cellular rejection (ACR), also known as Tcell-mediated rejection, which developed on the eighth postoperative day of kidney transplantation and communicates the problem of achieving a sufficient TAC blood concentration regardless of the high dose administration.…”