Effect of CYP3A5 gene polymorphisms on tacrolimus concentration/dosage ratio in adult liver transplant patients

Artificial Neural Network Analysis of Determinants of Tacrolimus Pharmacokinetics in Liver Transplant Recipients

BACKGROUND

The efficacy and toxicity of tacrolimus are closely related to its trough blood concentrations. Identifying the influencing factors of pharmacokinetics of tacrolimus in the early postoperative period is conducive to the optimization of the individualized tacrolimus administration protocol and to help liver transplant (LT) recipients achieve the target blood concentrations.

OBJECTIVE

This study aimed to develop an artificial neural network (ANN) for predicting the blood concentration of tacrolimus soon after liver transplantation and for identifying determinants of the concentration based on Shapley additive explanation (SHAP).

METHODS

In this retrospective study, we enrolled 31 recipients who were first treated with liver transplantation from the Department of Liver Transplantation and Hepatic Surgery, the First Affiliated Hospital of Shandong First Medical University (Shandong Provincial Qianfoshan Hospital) from November 2020 to May 2021. The basic information, biochemical indexes, use of concomitant drugs, and genetic factors of organ donors and recipients were used for the ANN model inputs, and the output was the steady-state trough concentration (C0) of tacrolimus after oral administration in LT recipients. The ANN model was established to predict C0 of tacrolimus, SHAP was applied to the trained model, and the SHAP value of each input was calculated to analyze quantitatively the influencing factors for the output C0.

RESULTS

A back-propagation ANN model with 3 hidden layers was established using deep learning. The mean prediction error was 0.27 ± 0.75 ng/mL; mean absolute error, 0.60 ± 0.52 ng/mL; correlation coefficient between predicted and actual C0 values, 0.9677; and absolute prediction error of all blood concentrations obtained by the ANN model, ≤3.0 ng/mL. The results indicated that the following factors had the most significant effect on C0: age, daily drug dose, genotype at CYP3A5 polymorphism rs776746 in both recipient and donor, and concomitant use of caspofungin. The predicted C0 value of tacrolimus in LT recipients increased in a dose-dependent manner when the daily dose exceeded 3 mg, whereas it decreased with age when LT recipients were older than 48 years. The predicted C0 was higher when recipients and donors had the genotype CYP3A5*3*3 than when they had the genotype CYP3A5*1. The predicted C0 value also increased with the use of caspofungin or Wuzhi capsule.

CONCLUSION AND RELEVANCE

The established ANN model can be used to predict the C0 value of tacrolimus in LT recipients with high accuracy and good predictive ability, serving as a reference for personalized treatment in the early stage after liver transplantation.

Tacrolimus therapeutic efficacy in post-liver transplant patients with Cytochrome P450 3A5 (CYP3A5) genetic polymorphisms

Genetic polymorphisms of CYP3A5 have been pointed out as factors that influenciates tacrolimus immunosuppressive efficacy in post liver transplant patients. This study aims to review the literature on the influence of cytochrome P450 3A5 (CYP3A5) genetic polymorphisms of tacrolimus in post-liver transplant patients. This study is a literature review. A combination of the descriptors "tacrolimus", "liver transplant", "cytochrome P-450 CYP3A inhibitors" and "genetic polymorphism" were used in the databases PubMed, Cochrane Library, Scopus and Scielo, being evaluated only studies between 2009 and 2019 in English, Portuguese or Spanish. A total of six studies, each from a different population were summarized. Initially, the pharmacological aspects of tacrolimus were discussed, including details on its pharmacodynamics, pharmacokinetics and toxicity After that, we analyzed the studies that correlates CYP3A5 genetic polymorphisms and tacrolimus efficacy, including the ethnical specifications and the general limittions of the studies. The CYP3A5 polymorphisms have pointed to alterations in the metabolism of tacrolimus according to the ethnic and populational genotype, specially the *1 and *3*3 alleles, reflecting in the need for dose adjustment and also in post liver transplant rejection.

Donor CYP3A5 Gene Polymorphism Alone Cannot Predict Tacrolimus Intrarenal Concentration in Renal Transplant Recipients

CYP3A5 gene polymorphism in recipients plays an important role in tacrolimus blood pharmacokinetics after renal transplantation. Even though CYP3A5 protein is expressed in renal tubular cells, little is known about the influence on the tacrolimus intrarenal exposure and hence graft outcome. The aim of our study was to investigate how the tacrolimus intrarenal concentration (C_tissue) could be predicted based on donor CYP3A5 gene polymorphism in renal transplant recipients. A total of 52 Japanese renal transplant patients receiving tacrolimus were enrolled in this study. Seventy-four renal biopsy specimens were obtained at 3 months and 1 year after transplantation to determine the donor CYP3A5 polymorphism and measure the C_tissue by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The tacrolimus C_tissue ranged from 52 to 399 pg/mg tissue (n = 74) and was weak but significantly correlated with tacrolimus trough concentration (C₀) at 3 months after transplantation (Spearman, r = 0.3560, p = 0.0096). No significant relationship was observed between the donor CYP3A5 gene polymorphism and C_tissue or C_tissue/C₀. These data showed that the tacrolimus systemic level has an impact on tacrolimus renal accumulation after renal transplantation. However, donor CYP3A5 gene polymorphism alone cannot be used to predict tacrolimus intrarenal exposure_. This study may be valuable for exploring tacrolimus renal metabolism and toxicology mechanism in renal transplant recipients.

Tacrolimus: Influence of the Posttransplant Concentration/Dose Ratio on Kidney Graft Function in a Two-Year Follow-Up

INTRODUCTION

Tacrolimus (TAC) metabolism rate has the potential to impact graft function after kidney transplantation (KTx). We aimed to analyze the relationship between the early post-KTx TAC C/D ratio (blood trough concentration normalized by total daily dose) and kidney graft function in a 2-year follow-up.

METHODS

We retrospectively analyzed data from 101 post-KTx patients at 3, 6, 12, and 24 months after KTx to identify the C/D ratio cutoff value optimal for dividing patients into fast and slow TAC metabolizers. We investigated the relationship between their TAC metabolism rate and graft function.

RESULTS

Patients were divided based on the TAC C/D ratio at 6 months after KTx of 1.47 ng/mL * 1 mg. Fast metabolizers (C/D ratio <1.47 ng/mL * 1 mg) presented with significantly worse graft function throughout the whole study period (p < 0.05 at each timepoint) and were significantly less likely to develop good graft function (estimated glomerular filtration rate ≥45 mL/min/1.73 m2) than slow metabolizers. Our model based on donor and recipient age, recipient sex and slow/fast metabolism status allowed for identification of patients with compromised graft function in 2-year follow-up with 66.7% sensitivity and 94.6% specificity.

CONCLUSION

Estimating TAC C/D ratio at 6 months post-KTx might help identify patients at risk of developing deteriorated graft function in a 2-year follow-up.

The impact of liver transplant recipient and donor genetic variability on tacrolimus exposure and transplant outcome

This study investigated the effect of recipient and donor genetic variability on dose-adjusted steady-state tacrolimus concentrations (C_ss ) and clinical outcomes 3 and 6 months after liver transplant. Twenty-nine recipients and matched donor blood samples were genotyped for 27 single nucleotide polymorphisms including CYP3A5*3 (rs776746), ABCB1 haplotype and immune genes. Associations between genetic variability and clinical parameters and C_ss and the occurrence of rejection and nephrotoxicity were analysed by multivariate and multinomial logistic regression modelling and Jonckheere-Terpstra tests examined the impact of combined donor/recipient CYP3A5 expression on C_ss . At 3 months post-transplant modelling revealed an association between tacrolimus C_ss and recipient CASP1 rs580523 genotype (P = 0.005), accounting for 52% C_ss variance. Jonckheere-Terpstra tests revealed that as combined donor/recipient CYP3A5 expression increased, C_ss decreased (P = 0.010 [3 months], 0.018 [6 months]). As this is the first report of CASP1 genetic variability influencing tacrolimus C_ss , further validation in larger cohorts is required.

CYP3A pharmacogenetic association with tacrolimus pharmacokinetics differs based on route of drug administration

Tacrolimus is prescribed to the majority of transplant recipients to prevent graft rejection, and although patients are maintained on oral administration, nonoral routes of administration are frequently used in the initial post-transplant period. CYP3A5 genotype is an established predictor of oral tacrolimus dose requirements, and clinical guideline recommendations exist for CYP3A5-guided dose selection. However, the association between CYP3A5 and nonoral tacrolimus administration is currently poorly understood, and differs from the oral tacrolimus relationship. In addition to CYP3A5, other pharmacogenes associated with CYP3A activity, including CYP3A4, CYP3A7 and POR have also been identified as predictors of tacrolimus exposure. This review will describe the current understanding of the relationship between these pharmacogenes and tacrolimus pharmacokinetics after oral and nonoral administration.