CYP3A5 unexpectedly regulates glucose metabolism through the AKT-TXNIP-GLUT1 axis in pancreatic cancer

CYP3A5 is a cytochrome P450 (CYP) enzyme that metabolizes drugs and contributes to drug resistance in cancer. However, it remains unclear whether CYP3A5 directly influences cancer progression. In this report, we demonstrate that CYP3A5 regulates glucose metabolism in pancreatic ductal adenocarcinoma. Multi-omics analysis showed that CYP3A5 knockdown results in a decrease in various glucose-related metabolites through its effect on glucose transport. A mechanistic study revealed that CYP3A5 enriches the glucose transporter GLUT1 at the plasma membrane by restricting the translation of TXNIP, a negative regulator of GLUT1. Notably, CYP3A5-generated reactive oxygen species were proved to be responsible for attenuating the AKT-4EBP1-TXNIP signaling pathway. CYP3A5 contributes to cell migration by maintaining high glucose uptake in pancreatic cancer. Taken together, our results, for the first time, reveal a role of CYP3A5 in glucose metabolism in pancreatic ductal adenocarcinoma and identify a novel mechanism that is a potential therapeutic target.

Drug-drug interaction between tacrolimus and caspofungin in Chinese kidney transplant patients with different CYP3A5 genotypes

Background

The effect of drug-drug interaction between tacrolimus and caspofungin on the pharmacokinetics of tacrolimus in different CYP3A5 genotypes has not been reported in previous studies.

Objectives

To investigate the effect of caspofungin on the blood concentration and dose of tacrolimus under different CYP3A5 genotypes.

Design

We conducted a retrospective cohort study in The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital from January 2015 to December 2022. All kidney transplant patients were divided into the combination or non-combination group based on whether tacrolimus was combined with caspofungin or not. Patients were subdivided into CYP3A5 expressers (CYP3A5*1/*1 or CYP3A5*1/*3) and CYP3A5 non-expressers (CYP3A5*3/*3).

Methods

Data from the combination and the non-combination groups were matched with propensity scores to reduce confounding by SPSS 22.0. A total of 200 kidney transplant patients receiving tacrolimus combined with caspofungin or not were enrolled in this study. Statistical analysis was conducted on the dose-corrected trough concentrations (C0/D) and dose requirements (D) of tacrolimus using independent sample two-sided t-test and nonparametric tests to investigate the impact on patients with different.

Results

In this study, the C0/D values of tacrolimus were not significantly different between the combination and non-combination groups (p = 0.054). For CYP3A5 expressers, there was no significant difference in tacrolimus C0/D or D values between the combination and non-combination groups (p = 0.359; p = 0.851). In CYP3A5 nonexpressers, the C0/D values of tacrolimus were significantly lower in the combination than in the non-combination groups (p = 0.039), and the required daily dose of tacrolimus was increased by 11.11% in the combination group.

Conclusion

Co-administration of caspofungin reduced tacrolimus blood levels and elevated the required daily dose of tacrolimus. In CYP3A5 non-expressers, co-administration of caspofungin had a significant effect on tacrolimus C0/D values. An approximate 10% increase in the weight-adjusted daily dose of tacrolimus in CYP3A5 non-expressers is recommended to ensure the safety of tacrolimus administration.

The impact of CYP3A5*3 on oral quetiapine: A population pharmacokinetic model in Chinese bipolar disorder patients

BACKGROUND

There is great interindividual difference in the plasma concentration of quetiapine, and optimizing quetiapine therapy to achieve a balance between efficacy and safety is still a challenge. In our study, a population pharmacokinetic (PPK) model considering genetic information was developed with the expectation of comprehensively explaining this observation in Chinese patients with bipolar disorder.

METHODS

Patients who were dispensed quetiapine and underwent the therapeutic drug monitoring (TDM) were included. The genotypes of CYP3A5*3, CYP2D6*10, and ABCB1 C3435T/G2677T were analyzed. Finally, a multivariable linear regression model was applied to describe the PPK of quetiapine considering the covariates weight, height and genotype information.

RESULTS

A total of 175 TDM points from 107 patients were adopted for PPK model development. Resultantly, the CL/F of quetiapine in CYP3A5 expressers was 81.1 CL/h, whereas it was 43.6 CL/h in CYP3A5 nonexpressers. The interindividual variability in CL/F was 47.7 %. However, neither the ABCB1 nor CYP2D6 genotype was significantly associated with the predictor of quetiapine clearance in our study.

LIMITATIONS

Only trough concentrations were collected, and the span between different points was relatively wide, impeding the application of the typical nonlinear compartment model for PPK analysis. In addition, this was a single-center study which limited the sample of wild-type CYP3A5 carriers.

CONCLUSIONS

The currently established PPK model of quetiapine considering the contribution of the CYP3A5 genotype could efficiently predict the population and individual pharmacokinetic parameters of Chinese bipolar disorder patients, which could better guide the personalized therapy with quetiapine, thus to achieve the best clinical response.

Pharmacogenomic implications of the differential distribution of CYP3A5 metabolic phenotypes among Latin American populations

This study shows that the distribution of CYP3A5 alleles (*1, *3, *6 and *7) and genotype-predicted CYP3A5 phenotypes vary significantly across Latin American cohorts (Brazilians and the One Thousand Genomes Admixed American superpopulation), as well as among subcohorts comprising individuals with the highest proportions of Native, European or sub-Saharan African ancestry. Differences in biogeographical ancestry across the study groups are the likely explanation for these results. The differential distribution of CYP3A5 phenotypes has major pharmacogenomic implications, affecting the proportion of individuals carrying high risk CYP3A5 phenotypes for the immunosuppressant tacrolimus and the number of patients that would need to be genotyped to prevent acute rejection in kidney transplant recipients under tacrolimus treatment.

Characterization of CYP3A5 Selective Inhibitors for Reaction Phenotyping of Drug Candidates

CYP3A is one of the most important classes of enzymes and is involved in the metabolism of over 70% drugs. While several selective CYP3A4 inhibitors have been identified, the search for a selective CYP3A5 inhibitor has turned out to be rather challenging. Recently, several selective CYP3A5 inhibitors have been identified through high-throughput screening of ~ 11,000 compounds and hit expansion using human recombinant enzymes. We set forth to characterize the three most selective CYP3A5 inhibitors in a more physiologically relevant system of human liver microsomes to understand if these inhibitors can be used for reaction phenotyping studies in drug discovery settings. Gomisin A and T-5 were used as selective substrate reactions for CYP3A4 and CYP3A5 to determine IC50 values of the two enzymes. The results showed that clobetasol propionate and loteprednol etabonate were potent and selective CYP3A5 reversible inhibitors with selectivity of 24-fold against CYP3A4 and 39-fold or more against the other major CYPs. The selectivity of difluprednate in HLM is much weaker than that in the recombinant enzymes due to hydrolysis of the acetate group in HLM. Based on the selectivity data, loteprednol etabonate can be utilized as an orthogonal approach, when experimental fraction metabolized of CYP3A5 is greater than 0.5, to understand CYP3A5 contribution to drug metabolism and its clinical significance. Future endeavors to identify even more selective CYP3A5 inhibitors are warranted to enable accurate determination of CYP3A5 contribution to metabolism versus CYP3A4.

Genotype-Guided Model for Prediction of Tacrolimus Initial Dosing After Lung Transplantation

The determination of the appropriate initial dose for tacrolimus is crucial in achieving the target concentration promptly and avoiding adverse effects and poor prognosis. However, the trial-and-error approach is still common practice. This study aimed to establish a prediction model for an initial dosing algorithm of tacrolimus in patients receiving a lung transplant. A total of 210 lung transplant recipients were enrolled, and 26 single nucleotide polymorphisms (SNP) from 18 genes that could potentially affect tacrolimus pharmacokinetics were genotyped. Associations between SNPs and tacrolimus concentration/dose ratio were analyzed. SNPs that remained significant in pharmacogenomic analysis were further combined with clinical factors to construct a prediction model for tacrolimus initial dose. The dose needed to reach steady state tacrolimus concentrations and achieve the target range was used to validate model prediction efficiency. Our final model consisted of 7 predictors-CYP3A5 rs776746, SLCO1B3 rs4149117, SLC2A2 rs1499821, NFATc4 rs1955915, alanine aminotransferase, direct bilirubin, and hematocrit-and explained 41.4% variance in the tacrolimus concentration/dose ratio. It achieved an area under the receiver operating characteristic curve of 0.804 (95% confidence interval, 0.746-0.861). The Hosmer-Lemeshow test yielded a nonsignificant P value of .790, suggesting good fit of the model. The predicted dose exhibited good correlation with the observed dose in the early postoperative period (r = 0.748, P less than .001). Our study provided a genotype-guided prediction model for tacrolimus initial dose, which may help to guide individualized dosing of tacrolimus in the lung transplant population in clinical practice.

Pharmacogenomic Analysis of CYP3A5*3 and Tacrolimus Trough Concentrations in Vietnamese Renal Transplant Outcomes

Purpose

CYP3A5 polymorphisms have been associated with variations in the pharmacokinetics of tacrolimus (Tac) in kidney transplant patients. Our study aims to quantify how the CYP3A5 genotype influences tacrolimus trough concentrations (C0) in a Vietnamese outpatient population by selecting an appropriate population pharmacokinetic model of Tac for our patients.

Patients and Methods

The external dataset was obtained prospectively from 54 data of adult kidney transplant recipients treated at the 103 Military Hospital. All published Tac population pharmacokinetic models were systematically screened from PubMed and Scopus databases and were selected based on our patient's available characteristics. Mean absolute prediction error (MAPE), mean prediction error, and goodness-of-fit plots were used to identify the appropriate model for finding the formula that identifies the influence of CYP3A5 genotype on the pharmacokinetic data of Vietnamese patients.

Results

The model of Zhu et al had a good predictive ability with MAPE of 19.29%. The influence of CYP3A5 genotype on tacrolimus clearance was expressed by the following formulas: CL/F=27 , 2 × [ ( WT/70 ) 0 , 75 ] × [ ( HCT/0 , 35 ) -0 , 501 ] × [ ( POD/180 ) 0 , 0306 ] × CYP3A5 ( L/h ) . The simulation result showed that Tac C0 was significantly higher in patients not expressing CYP3A5 (p< 0.001).

Conclusion

The incorporation of the CYP3A5 phenotype into Zhu's structural model has significantly enhanced our ability to predict Tacrolimus trough levels in the Vietnamese population. This study's results underscore the valuable role of CYP3A5 phenotype in optimizing the forecast of Tac concentrations, offering a promising avenue to assist health-care practitioners in their clinical decision-making and ultimately advance patient care outcomes.

CYP3A5 influences oral tacrolimus pharmacokinetics and timing of acute kidney injury following allogeneic hematopoietic stem cell transplantation

Introduction: Polymorphisms in genes responsible for the metabolism and transport of tacrolimus have been demonstrated to influence clinical outcomes for patients following allogeneic hematologic stem cell transplant (allo-HSCT). However, the clinical impact of germline polymorphisms specifically for oral formulations of tacrolimus is not fully described. Methods: To investigate the clinical impact of genetic polymorphisms in CYP3A4, CYP3A5, and ABCB1 on oral tacrolimus pharmacokinetics and clinical outcomes, we prospectively enrolled 103 adult patients receiving oral tacrolimus for the prevention of graft-versus-host disease (GVHD) following allo-HSCT. Patients were followed in the inpatient and outpatient phase of care for the first 100 days of tacrolimus therapy. Patients were genotyped for CYP3A5 *3 (rs776746), CYP3A4 *1B (rs2740574), ABCB1 exon 12 (rs1128503), ABCB1 exon 21 (rs2032582), ABCB1 exon 26 (rs1045642). Results: Expression of CYP3A5 *1 was highly correlated with tacrolimus pharmacokinetics in the inpatient phase of care (p < 0.001) and throughout the entirety of the study period (p < 0.001). Additionally, Expression of CYP3A5 *1 was associated with decreased risk of developing AKI as an inpatient (p = 0.06). Variants in ABCB1 were not associated with tacrolimus pharmacokinetics in this study. We were unable to discern an independent effect of CYP3A4 *1B or *22 in this population. Conclusion: Expression of CYP3A5 *1 is highly influential on the pharmacokinetics and clinical outcomes for patients receiving oral tacrolimus as GVHD prophylaxis following allo-HSCT.

Cyclosporine-A induced cytotoxicity within HepG2 cells by inhibiting PXR mediated CYP3A4/CYP3A5/MRP2 pathway

Cyclosporine-A (CsA) is currently used to treat immune rejection after organ transplantation as a commonly used immunosuppressant. Liver injury is one of the most common adverse effects of CsA, whose precise mechanism has not been fully elucidated. Pregnane X receptor (PXR) plays a critical role in mediating drug-induced liver injury as a key regulator of drug and xenobiotic clearance. As a nuclear receptor, PXR transcriptionally upregulates the expression of drug-metabolizing enzymes and drug transporters, including cytochrome P4503A (CPY3A) and multidrug resistance-associated protein 2 (MRP2). Our study established CsA-induced cytotoxic hepatocytes in an in vitro model, demonstrating that CsA dose-dependently increased the aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) level secreted in the HepG2 cell supernatant, as well as viability and oxidative stress of HepG2 cells. CsA also dose-dependently decreased the PXR, CYP3A4, CPY3A5, and MRP2 levels of HepG2 cells. Mechanistically, altering the expression of PXR, CYP3A4, CYP3A5, and MRP2 affected the impact of CsA on AST and LDH levels. Moreover, altering the expression of PXR also changed the level of CYP3A4, CPY3A5, and MRP2 of HepG2 cells treated by CsA. Our presented findings provide experimental evidence that CsA-induced liver injury is PXR tightly related. We suggest that PXR represents an attractive target for therapy of liver injury due to its central role in the regulation of the metabolizing enzymes CYP3A and MRP2-mediated bile acid transport and detoxification.

Association between CYP3A4, CYP3A5 and ABCB1 genotype and tacrolimus treatment outcomes among allogeneic HSCT patients

Aim: Successful treatment with tacrolimus to prevent graft versus host disease (GVHD) and minimize tacrolimus-related toxicities among allogeneic hematopoietic cell transplantation (alloHCT) recipients is contingent upon quickly achieving and maintaining concentrations within a narrow therapeutic range. The primary objective was to investigate associations between CYP3A4, CYP3A5 or ABCB1 genotype and the proportion of patients that attained an initial tacrolimus goal concentration following initiation of intravenous (iv.) and conversion to oral administration. Materials & methods: We retrospectively evaluated 86 patients who underwent HLA-matched (8/8) related donor alloHCT and were prescribed a tacrolimus-based regimen for GVHD prophylaxis. Results & conclusion: The findings of the present study suggests that CYP3A5 genotype may impact attainment of initial therapeutic tacrolimus concentrations with oral administration in alloHCT recipients.

Effect of genetic polymorphisms on the pharmacokinetics of gefitinib in healthy Chinese volunteers

Gefitinib is the first-generation drug of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) metabolised by the cytochrome P450 and transported by P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2). In the present study, the pharmacokinetics of gefitinib in healthy Chinese volunteers was investigated and the effect of genetic polymorphisms on its variability was evaluted.Forty-five healthy volunteers were administered a single dose of gefitinib and the blood samples were used for quantifying the concentration of gefitinib and genotyping fifteen single-nucleotide polymorphisms of cytochrome P450 enzymes (CYP3A4, CYP3A5, CYP2D6, CYP2C9 and CYP2C19) and drug transporters (ABCB1 and ABCG2).CYP3A5*3 (rs776746) polymorphism showed a significant influence, with higher gefitinib AUC0-t in carrier of CC genotype than in CT/TT genotype (BH-adjusted p value <0.05). For CYP2C9*3 (rs1057910), significant differences in pharmacokinetics of gefitinib were detected between carriers of AA and AC genotypes, with higher AUC0-t, AUC0-∞ and Cmax in carrier of AC genotype than in AA gen-otype (BH-adjusted p value <0.05). No associations were found between SNPs in CYP3A4, CYP2D6, CYP2C19, ABCB1, ABCG2 and the pharmacokinetics of gefitinib.The SNPs in CYP3A5*3 (rs776746) and CYP2C9*3 (rs1057910) were found to be associated with altered gefitinib pharmacokinetics in healthy Chinese volunteers.

[Study of allelic variants of the CYP2D6 and CYP3A genes on the effectiveness and safety of tamsulosin therapy in patients with BPH: results of a pilot study]

INTRODUCTION

Tamsulosin is a member of the group of selective 1-adrenoblockers. Tamsulosin monotherapy is the most common first-line option in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) and can be used regardless on severity of LUTS. The CYP2D6, CYP3A4, and CYP3A5 enzymes are involved in the metabolism of tamsulosin. Carriage of different allelic variants of CYP2D6, CYP3A4 and CYP3A5, involved in its metabolism, may potentially affect the variability of efficacy and safety of the drug.

AIM

To evaluate the effect of carriage of allelic variants of cytochrome P450 superfamily enzyme genes (CYP2D6*3, CYP2D6*4, CYP2D6*9, CYP2D6*10, CYP2D6*41, CYP3A4*3, CYP3A4*22 and CYP3A5*3) on the efficiency and safety of tamsulosin in patients with LUTS associated with BPH.

MATERIALS AND METHODS

All phases of the study were completed by 106 patients with LUTS/BPH (N40 according to ICD 10). All patients received monotherapy with tamsulosin 0.4 mg/day for a minimum of 8 weeks. Based on the severity of symptoms, they were divided into two groups using the International Prostate Symptom Score (IPSS). In Group 1, there were patients with moderate symptoms (IPSS score of 8-19) (n=57), while Group 2 consisted of those with severe symptoms (IPSS score >20) (n=49). Treatment outcomes were assessed using the IPSS score with determination of quality of life (QoL), transrectal ultrasound with evaluation of prostate volume and residual urine, and uroflowmetry. Follow-up visits were at 2, 4, and 8 weeks after the start of therapy. Genotyping of all patients was performed using polymerase chain reaction to determine the CYP2D6 (*3, *4, *9, *10, and *41), CYP3A4 (*3, *22), and CYP3A5*3 markers.

RESULTS

In the group of patients with moderate symptoms, carriers of the CYP2D6*10 and CYP2D6*41 polymorphisms showed a significantly greater reduction in symptoms according to the overall IPSS score at 8 weeks (p=0.046) and in the micturition symptom subscale starting from 4 weeks of treatment (p<0.05). Carriers of the CYP2D6*10 polymorphism in both groups were associated with a decrease in residual urine volume at 8 weeks (p<0.05). The presence of the CYP3A5*3 variant in those with severe symptoms significantly improved quality of life during therapy. Allelic variants of the CYP2D6 and CYP3A genes did not affect the frequency of adverse events.

CONCLUSION

The results obtained by calculating the prognostic significance of individual polymorphic markers pointed to the contribution of CYP2D6*10 and CYP2D6*41. Tamsulosin therapy is more effective in patients with LUTS who are carriers of these allele variants. The safety parameters of tamsulosin were not influenced by the studied polymorphic variants. It was found that CYP3A5*3 was associated with an increase in the subjective assessment of the patient's quality of life, but it is too early to draw final conclusions. The issue of the contribution of genetic factors to the efficiency and safety of treatment of LUTS in BPH requires further study with a larger sample size and analyzed parameters.

CYP3A5*3 and CYP3A4*22 Cluster Polymorphism Effects on LCP-Tac Tacrolimus Exposure: Population Pharmacokinetic Approach

The aim of the study is to develop a population pharmacokinetic (PopPK) model and to investigate the influence of CYP3A5/CYP3A4 and ABCB1 single nucleotide polymorphisms (SNPs) on the Tacrolimus PK parameters after LCP-Tac formulation in stable adult renal transplant patients. The model was developed, using NONMEM v7.5, from full PK profiles from a clinical study (n = 30) and trough concentrations (C0) from patient follow-up (n = 68). The PK profile of the LCP-Tac formulation was best described by a two-compartment model with linear elimination, parameterized in elimination (CL/F) and distributional (CLD/F) clearances and central compartment (Vc/F) and peripheral compartment (Vp/F) distribution volumes. A time-lagged first-order absorption process was characterized using transit compartment models. According to the structural part of the base model, the LCP-Tac showed an absorption profile characterized by two transit compartments and a mean transit time of 3.02 h. Inter-individual variability was associated with CL/F, Vc/F, and Vp/F. Adding inter-occasion variability (IOV) on CL/F caused a statistically significant reduction in the model minimum objective function MOFV (p < 0.001). Genetic polymorphism of CYP3A5 and a cluster of CYP3A4/A5 SNPs statistically significantly influenced Tac CL/F. In conclusion, a PopPK model was successfully developed for LCP-Tac formulation in stable renal transplant patients. CYP3A4/A5 SNPs as a combined cluster including three different phenotypes (high, intermediate, and poor metabolizers) was the most powerful covariate to describe part of the inter-individual variability associated with apparent elimination clearance. Considering this covariate in the initial dose estimation and during the therapeutic drug monitoring (TDM) would probably optimize Tac exposure attainments.

Effects of CYP3A5 Genotypes on Thrombocytopenia in Liver Transplantation Patients Treated with Tacrolimus

BACKGROUND

Thrombocytopenia is a complication after liver transplantation. This study's aims were to evaluate the role of CYP3A5 genotypes on tacrolimus-induced thrombocytopenia after orthotopic liver transplantation.

METHODS

In this retrospective case-control study, data from 100 patients who underwent deceased-donor liver transplantation (DDLT) were divided into CYP3A5*3 genotype (donor/recipient) tacrolimus fast- (A*/A*, n = 22), intermediate- (A*/GG, n = 20; GG/A*, n = 31) and slow-metabolizer (GG/GG, n = 27) groups. Platelet count changes and prognosis for 180 days after surgery were compared.

RESULTS

Platelet counts declined significantly after DDLT, especially on postoperative day (POD) 3, and continued at low levels for a week thereafter in all groups. In the GG/GG group, platelet counts on POD3 (50.29 ± 5.44 × 109/L) were the lowest among the groups (A*/A*, 71.00 ± 6.22 × 109/L; A*/GG, 57.95 ± 6.21 × 109/L; GG/A*, 75.90 ± 5.56 × 109/L) (p = 0.006). Compared with the A*/A* genotype, tacrolimus nadir levels were significantly higher in GG/GG genotype patients, who also exhibited a higher incidence of hemorrhage (22.2%, p = 0.011). A combination of a nadir blood concentration of tacrolimus ≥ 4.74 ng/mL and spleen size ≥ 165.5 mm was a risk factor for increased thrombocytopenia after DDLT on POD3, with an AUC of 0.735 (sensitivity, 77.2%; specificity, 41.7%).

CONCLUSIONS

A high blood concentration of tacrolimus after the early stage of DDLT is a major risk factor for hemorrhage. For the CYP3A5 genotype (GG/GG), controlling the blood concentration of tacrolimus below the target concentration until POD3 can avoid thrombocytopenia-related complications.

The impact of CYP3A4 and CYP3A5 genetic variations on tacrolimus treatment of living-donor Egyptian kidney transplanted patients

BACKGROUND

Tacrolimus (TAC) is the mainstay of immunosuppressive regimen for kidney transplantations. Its clinical use is complex due to high inter-individual variations which can be partially attributed to genetic variations at the metabolizing enzymes CYP3A4 and CYP3A5. Two single nucleotide polymorphisms (SNPs), CYP3A4*22 and CYP3A5*3, have been reported as important causes of differences in pharmacokinetics that can affect efficacy and/or toxicity of TAC.

OBJECTIVE

Investigating the effect of CYP3A4*22 and CYP3A5*3 SNPs individually and in combination on the TAC concentration in Egyptian renal recipients.

METHODS

Overall, 72 Egyptian kidney transplant recipients were genotyped for CYP3A4*22 G>A and CYP3A5*3 T>C. According to the functional defect associated with CYP3A variants, patients were clustered into: poor (PM) and non-poor metabolizers (Non-PM). The impact on dose adjusted through TAC concentrations (C0) and daily doses at different time points after transplantation was evaluated.

RESULTS

Cyp3A4*1/*22 and PM groups require significantly lower dose of TAC (mg/kg) at different time points with significantly higher concentration/dose (C0/D) ratio at day 10 in comparison to Cyp3A4*1/*1 and Non-PM groups respectively. However, CyP3A5*3 heterozygous individuals did not show any significant difference in comparison to CyP3A5*1/*3 individuals. By comparing between PM and Non-PM, the PM group had a significantly lower rate of recipients not reaching target C0 at day 14.

CONCLUSION

This is the first study on Egyptian population to investigate the impact of CYP3A4*22 and CYP3A5*3 SNPs individually and in combination on the TAC concentration. This study and future multicenter studies can contribute to the individualization of TAC dosing in Egyptian patients.

Association between CYP3A4/CYP3A5 genetic polymorphisms and treatment outcomes of atorvastatin worldwide: is there enough research on the Egyptian population?

INTRODUCTION

Atorvastatin is regarded as the most frequently prescribed statin worldwide for dyslipidemia. However, clinical response and risk of adverse effects to statin therapy are associated with genetic variations. Numerous research linked statins pharmacokinetics (PK) variations to genetic polymorphisms in cytochromes P450 (CYPs) metabolic enzymes.

OBJECTIVE

This article reviews the association between CYP3A4/5 genetic variations and response to atorvastatin therapy globally, which includes atorvastatin PK, and the risk for adverse reactions, with a hint to the Egyptians.

METHODS

Up to March 30, 2022, electronic medical databases like PubMed, Web of Science, MEDLINE, and Egyptian Knowledge Bank (EKB) were searched. All articles that highlighted the relationship between CYP3A4/5 genetic polymorphisms and atorvastatin efficacy/safety profile were included in this review.

RESULTS

Initially, 492 articles were retrieved after an exhaustive search. There were 24 articles included according to the inclusion criteria. Findings of association studies of CYP3A4/5 genetic polymorphisms with response to atorvastatin varied among different ethnicities. CYP3A4*1B was associated with better therapeutic outcomes after atorvastatin therapy in Chileans and vice versa in Americans. Caucasians with myalgia while using atorvastatin were at significant risk of suffering severe muscle damage if they were carriers of CYP3A5*3/*3. As far as we can report for the Egyptian population, the impact of CYP3A4/5 genetic variations on the response to atorvastatin therapy was understudied.

CONCLUSION

More pharmacogenetic studies amongst diverse populations worldwide, like the Egyptian population, are necessary to detect further atorvastatin-gene interactions.

CYP3A5 Genotype-Dependent Drug-Drug Interaction Between Tacrolimus and Voriconazole in Chinese Kidney Transplant Patients

BACKGROUND

The effect of drug-drug interaction (DDI) between tacrolimus and voriconazole on the pharmacokinetics of tacrolimus in different CYP3A5 genotypes has not been reported in previous studies.

OBJECTIVE

The objective of this study was to investigate whether CYP3A5 genotype could influence tacrolimus-voriconazole DDI in Chinese kidney transplant patients.

METHODS

All kidney transplant patients were divided into combination and non-combination groups based on whether tacrolimus was combined with or without voriconazole. Each group was subdivided into CYP3A5 expresser (CYP3A5*1/*1 or CYP3A5*1/*3) and CYP3A5 nonexpresser (CYP3A5*3/*3). A retrospective analysis compared tacrolimus dose (D)-corrected trough concentrations (C0) (C0/D) between combination and non-combination groups, respectively. Tacrolimus C0/D was also compared between CYP3A5 expresser and nonexpresser in both groups.

RESULTS

The C0/D values of tacrolimus were significantly different between CYP3A5 expresser and nonexpresser in combination group (378.20 [219.38, 633.48] ng/mL/[mg/kg/d] vs 720.00 [595.35, 1681.50] ng/mL/[mg/kg/d], P = 0.0010). Either in CYP3A5 expresser or nonexpresser, we found a statistically significant difference in tacrolimus C0/D between combination and non-combination group (P < 0.0001). The increase in CYP3A5 nonexpresser was 1.38 times higher than that in CYP3A5 expresser (320.93% vs 232.19%).

CONCLUSION AND RELEVANCE

The median C0/D values were 90.38% higher in kidney transplant recipients with CYP3A5*3/*3 genotype than in those with CYP3A5*1/*1 or CYP3A5*1/*3 genotype when treated with both tacrolimus and voriconazole. A CYP3A5 genotype-dependent DDI was found between tacrolimus and voriconazole. Therefore, personalized therapy accounting for CYP3A5 genotype detection and therapeutic drug monitoring is necessary for kidney transplant patients when treating with tacrolimus and voriconazole.

A systematic review and meta-analysis recite the efficacy of Tacrolimus treatment in renal transplant patients in association with genetic variants of CYP3A5 gene

Tacrolimus is an immunosuppressant with a narrow therapeutic index and pharmacokinetic variability. This variability may be attributed to genetic variants in gene CYP3A5 associated with Tacrolimus metabolism. Studies focusing on genetic variants in the CYP3A5 gene associated with Tacrolimus metabolism have been published, a meta-analysis of these published articles may provide a direction that can change the future research and clinical management of renal transplant patients. In this systematic review and meta-analysis, we have reviewed and analyzed the studies and clinical trials conducted to determine the association between genetic variants of CYP3A5 and Tacrolimus metabolism from the PubMed database and clinical trials (www.clinicaltrials.gov). This meta-analysis also assessed the correlation of CYP3A5 genotype (rs776746) with concentration/dose (Co/D) of Tacrolimus in renal transplant patients. The 59 published articles on genetic association of the CYP3A5 on Tacrolimus doses were reviewed for this systematic review. Meta-analysis showed that the Tacrolimus Co/D ratio is significantly lower in the CYP3A5 expressor group as compared with non-expressor in Asian, European as well as in mixed populations at any post-transplant period (P<0.0001). Our study further confirmed that the CYP3A5 variant (rs776746) is clinically relevant for the dose determination of Tacrolimus. Variations in Tacrolimus Co/D have been found to be significantly linked to the patient's CYP3A5 genetic variant (rs776746). The addition of other genetic variants involved in the pharmacokinetic of Tacrolimus may determine efficient regimen for drug dose. Our meta-analysis confirmed that the CYP3A5 genetic variant (rs776746) analysis is relevant in personalizing the Tacrolimus dose determination in renal transplant patients.

Association of CYP3A5*3, CYP3A4*18 & CYP2B6*6 polymorphisms with imatinib treatment outcome in Azerbaijani chronic myeloid leukaemia patients

Background & objectives

Imatinib mesylate (IM) is a reliable first line treatment for chronic myeloid leukaemia (CML). Nevertheless, despite promising results, a considerable proportion of patients develop resistance to the drug. Cytochrome P450 (CYP) enzymes play a crucial role in IM metabolism. Thus, point mutations in CYP genes may modify IM enzyme activity resulting in insufficient treatment response. This investigation was aimed to identify the functional impact of CYP3A5*3, CYP3A4*18 and CYP2B6*6 polymorphisms on the IM response in patients with CML in Azerbaijan.

Methods

Genotyping of CYP3A5*3, CYP3A4*18 and CYP2B6*6 was performed in 153 patients (102 IM non-responders and 51 IM responders) with CML by the PCR-restriction fragment length polymorphism (RFLP) assays. The odds ratios (ORs) with 95 per cent confidence intervals (CIs) were applied to assess the association between allelic variants and IM therapy outcome. The results were validated by sequencing.

Results

The frequency of the CYP3A4*18 allele was considerably lower in the responder's group (97.1 vs. 100%; P=0.036). For CYP3A5*3, the allelic frequency was slightly higher among the IM responders (100 vs. 99.02%) with no significant difference. Although patients heterozygous (TC) for CYP2B6*6 demonstrated a higher risk of acquiring resistance (OR 1.04; 95% CI: 0.492-2.218), differences were not significant (P=0.909). In addition, the homozygous genotype (TT) demonstrated a lower risk of unresponsiveness (OR 0.72; 95% CI: 0.283-1.836), but associations were not significant (P=0.491).

Interpretation & conclusions

Our results demonstrated that CYP3A4*18 was significantly associated with IM treatment response in patients with CML in Azerbaijan, whereas rather common CYP3A5*3 was identified to have no such association.

Implementation of Clinical Cytochrome P450 3A Genotyping for Tacrolimus Dosing in a Large Kidney Transplant Program

Tacrolimus is a calcineurin inhibitor with a narrow therapeutic range and is metabolized by cytochrome P450 (CYP) isoenzymes CYP3A4 and CYP3A5. The Clinical Pharmacogenetic Implementation Consortium published evidence-based guidelines for CYP3A5 normal/intermediate metabolizers prescribed tacrolimus, yet few transplant centers have implemented routine testing. The objective of this study was to implement preemptive CYP3A genotyping into clinical practice in a large kidney transplant program and to evaluate workflow feasibility, potential clinical benefit, and reimbursement to identify barriers and determine sustainability. Preemptive pharmacogenetic testing for CYP3A5 and CYP3A4 was implemented in all patients listed for a kidney transplant as part of standard clinical care. Genotyping was performed at the listing appointment, results were reported as discrete data in the electronic medical record, and education and clinical decision support alerts were developed to provide pharmacogenetic-recommended tacrolimus dosing. During this initial phase, all patients were administered standard tacrolimus dosing, and clinical and reimbursement outcomes were collected. Greater than 99.5% of genotyping claims were reimbursed by third-party payers. CYP3A5 normal/intermediate metabolizers had significantly fewer tacrolimus trough concentrations within the target range and a significantly longer time to their first therapeutic trough compared to poor metabolizers. The challenge of tacrolimus dosing is magnified in the African American population. The US Food and Drug Administration drug label recommends increased starting doses in African ancestry, yet only ≈66% of African Americans in our cohort were normal/intermediate metabolizers who required higher doses. Routine CYP3A5 genotyping may overcome this issue by using genotype over race as a more accurate predictor of drug response.

Pregnancy related hormones increase CYP3A mediated buprenorphine metabolism in human hepatocytes: a comparison to CYP3A substrates nifedipine and midazolam

Introduction: Pregnancy increases the clearance of CYP3A4 substrate drugs and pregnancy-related hormones (PRHs) induce hepatic CYP3A4 expression and metabolism. However, it remains unclear to what extent the magnitude of PRH-evoked changes in hepatic CYP3A metabolism varies across multiple substrates. This study quantified the impact of PRHs on CYP3A protein concentrations and buprenorphine metabolism in human hepatocytes, and compared the magnitude of these effects to nifedipine and midazolam metabolism. Methods: Sandwich-cultured human hepatocytes (SCHH) from female donors were exposed to PRHs, administered in combination across a range of physiologically relevant concentrations, for 72 h. Absolute protein concentrations of CYP3A4, CYP3A5, and CYP3A7 in SCHH membrane fractions were quantified by nanoLC-MS/MS, and norbuprenorphine (nor-BUP), dehydro-nifedipine (dehydro-NIF), and 1-hydroxy-midazolam (1-OH-MDZ) formation was evaluated. Results: Compared to control, PRH exposure increased CYP3A4, CYP3A7, and total CYP3A protein concentrations, but not CYP3A5 concentrations, and increased nor-BUP, dehydro-NIF, and 1-OH-MDZ formation in a concentration-dependent manner. The formation of nor-BUP, dehydro-NIF, and 1-OH-MDZ each positively correlated with PRH-mediated changes in total CYP3A protein concentrations. The PRH-evoked increase in nor-BUP formation was evident in all donors; however, the PRH induction of dehydro-NIF and 1-OH-MDZ formation was diminished in a hepatocyte donor with high basal CYP3A5 expression. Discussion: These findings demonstrate that PRHs increase buprenorphine, nifedipine, and midazolam metabolism in SCHH via induction of CYP3A4 and total CYP3A protein concentrations, and the magnitude of these effects vary across hepatocyte donors in a substrate-specific manner. These data provide insight into the contribution of PRH induction of CYP3A4 metabolism to increased buprenorphine clearance during pregnancy.

Influence of genetic variants on the pharmacokinetics and pharmacodynamics of sirolimus: a systematic review

Sirolimus is an antiproliferative and immunosuppressive compound inhibiting the mTOR pathway, which is often activated in congenital low-flow vascular malformations. Studies have demonstrated the efficacy of sirolimus for this disease. Studies in kidney transplant patients suggest that genetic variants can influence these pharmacokinetic parameters. Therefore, a systematic literature search was performed to gain insight into pharmacogenetic studies with sirolimus. Most studies investigated CYP3A4 and CYP3A5, with inconsistent results. No pharmacogenetic studies focusing on sirolimus have been performed for low-flow vascular malformations. We analyzed two common variants of CYP3A4 and CYP3A5 (CYP3A4*22 and CYP3A5*3, respectively) in patients (n = 59) with congenital low-flow vascular malformations treated with sirolimus. No association with treatment outcome was identified in this small cohort of patients.

Composite CYP3A (CYP3A4 and CYP3A5) phenotypes and influences on tacrolimus dose adjusted concentration in adult heart transplant recipients

CYP3A5 genetic variants are associated with tacrolimus metabolism. Controversy remains on whether CYP3A4 increased [* 1B (rs2740574), *1G (rs2242480)] and decreased function [*22 (rs35599367)] genetic variants provide additional information. This study aims to address whether tacrolimus dose-adjusted trough concentrations differ between combined CYP3A (CYP3A5 and CYP3A4) phenotype groups. Significant differences between CYP3A phenotype groups in tacrolimus dose-adjusted trough concentrations were found in the early postoperative period and continued to 6 months post-transplant. In CYP3A5 nonexpressers, carriers of CYP3A4*7Bor *7G variants (Group 3) compared to CYP3A4*1/*1 (Group 2) patients were found to have lower tacrolimus dose-adjusted trough concentrations at 2 months. In addition, significant differences were found among CYP3A phenotype groups in the dose at discharge and time to therapeutic range while time in therapeutic range was not significantly different. A combined CYP3A phenotype interpretation may provide more nuanced genotype-guided TAC dosing in heart transplant recipients.

Newly identified cytochrome P450 3A genes of tree shrews and pigs are expressed and encode functional enzymes

Novel cytochrome P450 3A5 (CYP3A5) cDNA in tree shrews (which are non-rodent primate-like species) and pig CYP3A227 cDNA were identified, along with known pig CYP3A22, CYP3A29, and CYP3A46 cDNAs. All five cDNAs contained open reading frames encoding a polypeptide of 503 amino acids that shared high sequence identity (72-78 %) with human CYP3A4 and were more closely related to human CYP3As than rat CYP3As by phylogenetic analysis. CYP3A5 was the only CYP3A in the tree shrew genome, but pig CYP3A genes formed a CYP3A gene cluster in the genomic region corresponding to that of human CYP3A genes. Tree shrew CYP3A5 mRNA was predominantly expressed in liver and small intestine, among the tissues analyzed, whereas pig CYP3A227 mRNA was most abundantly expressed in jejunum, followed by liver. Metabolic assays established that tree shrew CYP3A5 and pig CYP3A proteins heterologously expressed in Escherichia coli metabolized typical human CYP3A4 substrates nifedipine and midazolam. These results suggest that novel tree shrew CYP3A5 and pig CYP3A227 were functional enzymes able to metabolize human CYP3A4 substrates in liver and small intestine, similar to human CYP3A4, although pig CYP3A227 mRNA was minimally expressed in all tissues analyzed.

Higher number of tacrolimus dose adjustments in kidney transplant recipients who are extensive and intermediate CYP3A5 metabolizers

Kidney transplant recipients carrying the CYP3A5*1 allele have lower tacrolimus troughs, and higher dose requirements compared to those with the CYP3A5*3/*3 genotype. However, data on the effect of CYP3A5 alleles on post-transplant tacrolimus management are lacking. The effect of CYP3A5 metabolism phenotypes on the number of tacrolimus dose adjustments and troughs in the first 6 months post-transplant was evaluated in 78 recipients (64% Caucasians). Time to first therapeutic concentration, percentage of time in therapeutic range (TTR), and estimated glomerular filtration rate (eGFR) were also evaluated. Fifty-five kidney transplant recipients were CYP3A5 poor metabolizers (PM), 17 were intermediate metabolizers (IM), and 6 were extensive metabolizers (EM). Compared to PMs, EMs/IMs had significantly more dose adjustments (6.1 vs. 8.1, p = .015). Overall, 33.82% of trough measurements resulted in a dose change. There was no difference in the number of tacrolimus trough measurements between PMs and EM/IMs. The total daily tacrolimus dose requirements were higher in EMs and IMs compared to PMs (<.001). TTR was ∼50% in the PMs and EMs/IMs groups. CYP3A5 EM/IM metabolizers have more tacrolimus dose changes and higher dose requirements which increases clinical management complexity. Larger studies are needed to assess the cost and benefits of including genotyping data to improve clinical management.

Association of STAT3, CYP3A5, and ABCG2 Polymorphisms With Osimertinib-induced Adverse Events in NSCLC Patients

BACKGROUND/AIM

Osimertinib is a key drug for treating epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC). Genetic differences may be associated to adverse events (AEs) induced by osimertinib. This retrospective observational multicenter study evaluated the association of genotypes, including STAT3 -1697C>G, CYP3A5 6986A>G, and ABCG2 421C>A, with the incidence of osimertinib-induced AEs in patients with EGFR mutation-positive NSCLC.

PATIENTS AND METHODS

A total of 85 patients treated with osimertinib (Institution A: 33 patients, Institution B: 52 patients) were enrolled in the study. Single nucleotide polymorphisms were determined by real-time PCR, and the incidence of AEs was compared for each genotype.

RESULTS

Paronychia incidence was 59% for the CC genotype, 19% for the CG genotype, and 19% for the GG genotype at STAT3 -1697C>G. A genotype-related trend was observed (Cochran-Armitage test, p=0.009). Multivariate analysis showed that the CC genotype at STAT3 -1697C>G and female sex were significant independent factors associated with paronychia [odds ratio (OR)=6.41, 95% confidence interval (CI)=1.94-21.20 and OR=3.40, 95%CI=1.03-11.22, respectively]. The incidence of diarrhea was 53% for the CC genotype, 30% for the AC genotype, and 29% for the AA genotype at ABCG2 421C>A, and a genotype-related trend was observed (p=0.048). However, the CC genotype at ABCG2 421C>A was not a significant independent factor associated with diarrhea in multivariate analysis. No significant associations were detected between other polymorphisms and the incidence of AEs.

CONCLUSION

STAT3 -1697C>G may be a novel risk factor for osimertinib-induced paronychia in patients with NSCLC.

High hepatic and plasma exposures of atorvastatin in subjects harboring impaired cytochrome P450 3A4∗16 modeled after virtual administrations and possibly associated with statin intolerance found in the Japanese adverse drug event report database

Drug interactions between atorvastatin and cytochrome P450 (P450) 3A substrates/inhibitors lead to an increased incidence of skeletal muscle or hepatic toxicity. However, in this survey, among 483 Japanese subjects administered atorvastatin alone, more than half (258) experienced statin intolerance and were unable to continue using the drug. Although many factors underly atorvastatin toxicity, the intrinsic clearance rate might be a contributing causal factor. The impaired P450 3A4 p.Thr185Ser variant, CYP3A4∗16 (rs12721627), has been identified in East Asians with an allele frequency of 2.2%. Pharmacokinetically modeled plasma concentrations of atorvastatin increased after a virtual oral dose of 40 mg in CYP3A4∗16 homozygotes; the maximum concentration and area under the concentration curve, respectively, were 3.3-fold and 4.2-fold those in subjects homozygous for CYP3A4∗1. In subjects with CYP3A4∗16/∗16, the virtual hepatic concentrations of atorvastatin after daily doses of 10 mg for a week were similar to or higher than the plasma concentrations. These results suggest that the estimated high virtual plasma and hepatic exposures obtained by pharmacokinetic modeling in subjects harboring impaired allele CYP3A4∗16 may be one of the causal factors for statin intolerance in a manner similar to the well-known drug interactions caused by co-administrations of CYP3A inhibitors.

The prevalence of pharmacogenetic variants of vitamin K epoxide reductase complex subunit 1 gene (rs9923231), cytochrome P450 family 2 subfamily C member 9 gene (rs1799853) and cytochrome P450 family 3 subfamily-A member-5 gene (rs776746) among 13 ethnic groups of Pakistan

BACKGROUND

Pharmacogenomics (PGx) plays a central role in the selection of targeted therapies that underpins precision-medicine. We investigated the prevalence of three important pharmacogenetic variants of VKORC1, CYP2C9, and CYP3A5 genes among Pakistani populations.

METHODS

A total of 1104 individuals were included representing thirteen major ethnicities. Samples were genotyped by using PCR-RFLP analysis. The allelic and genotypic frequencies of the three SNV's were calculated and were compared with the world's population data (ALFA, gnomAD, and 1000Genome, 1 K databases), using the chi-square test.

RESULTS

We found overall frequencies of functional-alleles of VKORC1 0.43, CYP2C9 0.94, and CYP3A5 0.14 in our population. Data showed a low prevalence of homozygous functional genotypes of VKORC1 (0.18; 0.0-0.45) and CYP3A5 (0.04; 0.0-0.22), and a high frequency of CYP2C9 (0.885; 0.80-1.0) across ethnicities. Genotyping distribution of VKCOR1 functional genotype was varied across ethnic groups such as 0.0-0.10 in Brahuis and Mohanas, Sindhis, Rajputs, and Gujjars populations, 0.11-0.20 in Makranis, Parsis, and Burusho populations, and 0.20-0.30 in Kalash, Kashmiris and Baloch populations. The highest VKORC1 (CC) was found in Pathans (0.45) and Hazaras (0.39) populations. Interestingly, we found a high prevalence of functional genotype CYP2C9 (rs1799853; C) and non-functional genotype of CYP3A5 (rs776746; T) across various ethnic groups of Pakistan.

CONCLUSION

Data regarding prevalence of clinically important pharmacogenomics SNVs could be useful in drug adjustment and avoiding adverse drug reactions in a specific ethnic population. This could help in moving current medical practices toward precision medicine in our part of the world.

Impact of single-nucleotide polymorphisms on tacrolimus pharmacokinetics in liver transplant patients after switching to once-daily dosing

BACKGROUND

The effects of multidrug resistance-1 (MDR1), ABCC2, and P450 oxidoreductase (POR)*28 gene polymorphisms on tacrolimus metabolism following a switch to once-daily dosing have not been elucidated. We investigated the effects of recipient and donor CYP3A5, MDR1, ABCC2, and POR*28 polymorphisms on tacrolimus pharmacokinetics following a switch to once-daily tacrolimus dosing.

METHODS

Eighty-seven liver transplant recipients who were switched from twice- to once-daily tacrolimus dosing following living-donor liver transplantation and 81 matched donors were genotyped for CYP3A5, MDR1 (1236C>T, 2677G>T/A, and 3435C>T), ABCC2 (-24C>T, 1249G>A, and 3972C>T), and POR*28. Tacrolimus dose-adjusted trough levels (C0/dose) before and after the switch were determined and calculated based on past medical records. Recipients were divided into two groups, one group constituted of 38 patients with a C0/dose decrease of less than 30% following conversion (group 1) and the other constituted of 49 patients with a C0/dose decrease of ≥ 30% (group 2).

RESULTS

CYP3A5 *1/*3 and *3/*3 were more frequent in recipients in group 1 (60.5% vs. 36.8%), while CYP3A5 *1/*1 was more frequent in group 2 (59.2% vs. 32.7%) (p = 0.016). The proportions of donor ABCC2 1249G>A genotypes AA and AG were higher in group 2 than in group 1 (20.4% vs. 5.3%; p = 0.042).

CONCLUSION

Recipient CYP3A5 polymorphism and donor ABCC2 1249G>A polymorphism affected tacrolimus pharmacokinetics following the switch to once-daily dosing. Dose adjustment to maintain therapeutic tacrolimus levels following the switch to once-daily dosing should be considered based on polymorphisms in both the recipient and donor.

Effect of Wuzhi preparations on tacrolimus in CYP3A5 expressers during the early period after transplantation: A real-life experience from heart transplant recipients

BACKGROUND

Genetic polymorphisms and drug interactions are associated with tacrolimus exposure. This study aimed to evaluate the effect of Wuzhi (WZ) preparations on tacrolimus (TAC) concentration and dose requirements in heart transplant recipients with the CYP3A5*1 allele during the early period after transplantation.

METHODS

A total of 167 adult heart transplant recipients with the CYP3A5*1 allele were included and divided into the WZ group (n = 115) and the WZ-free group (n = 52). Blood trough concentrations of TAC were detected and the dose-adjusted concentration (C₀/D) and dose requirement for achieving the TAC therapeutic range were compared between the two groups. The change in C₀/D and dose of TAC were evaluated before and after co-administration with WZ preparations.

RESULTS

No significant differences in TAC C₀/D and dose requirement were observed between the WZ and WZ-free groups. However, the TAC C₀/D in the WZ group was significantly increased an average of 2.10-fold after co-administration of WZ. Moreover, the degree of elevation was related to the dose of the active ingredient (Schisantherin A). Furthermore, ALT, AST, and TB levels were significantly reduced after administration of WZ preparations.

CONCLUSION

Co-administration of the WZ/TAC preparation, in heart transplant recipients carrying the CYP3A5*1 allele, considerably increased TAC concentration (C₀/D) while decreased high levels of leading indicators in the liver function. More importantly, the effect of the WZ/TAC preparation on C₀/D was a dose-dependent event. However, our finding needs to be further confirmed in a larger sample size.

MD Investigation on the Interaction between Carbamazepine and Two CYP Isoforms, CYP3A4 and CYP3A5

Carbamazepine (CBZ), a commonly prescribed antiepileptic drug, in human liver, is mainly metabolized by two isoforms of cytochrome P450 (CYP), CYP3A4 and CYP3A5. Therefore, the binding of CBZ with these two enzymes plays crucial role in the biotransformation of the drug into its active metabolite. In the present work, classical molecular dynamics (MD) simulation was used to investigate the detailed interaction mechanism between CBZ and these two CYP isoforms at the atomic level. The results revealed that although CBZ can bind with the two proteins, all kinds of the interactions, including hydrogen bonds, salt bridges, hydrophobic interaction, and π-π interaction, are isoform specific. The specificity directly leads to a binding environment difference at the active sites of the two isoforms, as represented by the electrostatic surface potential maps, which further results in the varied dynamic behavior of CBZ in the two isoforms. Our research will help to deepen the understanding of the physiological functions of CYP isoforms and opens the door for the rational design and development of isoform-specific inhibitors.

CYP3A5 Expressor Genotype of the Transplanted Kidney Increases the Risk of Preterm Graft Loss and Acute Rejection

INTRODUCTION

Tacrolimus is metabolized mainly in the liver by the CYP3A enzyme family, with a particularly well-documented role of CYP3A5. CYP3A5 is also expressed in the renal tissue and is present in the transplanted kidney. To date, the association between donor CYP3A5 polymorphisms and transplant outcome remains poorly understood. The aim of this study was to assess the effect of donor CYP3A5 expression on early and long-term transplant outcomes.

METHODS

A retrospective cohort study including 207 patients who received kidney grafts from 110 deceased donors was conducted at a single Central European Center. Tissue samples from all donors were studied for CYP3A5 single-nucleotide polymorphism (rs776746). Death-censored graft loss within 5-year follow-up, acute rejection occurrence, and kidney function, measured using serum creatinine and MDRD eGFR, were compared between groups of patients with allografts from rs776746 carriers (CYP3A5 expressors) and noncarriers (CYP3A5 nonexpressors).

RESULTS

Recipients who received kidneys from CYP3A5 expressors (n = 24) were at significantly higher risk of death-censored graft loss within 5-year follow-up (adjusted HR, 95% CI: 6.82, 2.01-23.12; p = 0.002) and acute rejection within the 1st posttransplant year (adjusted OR, 95% CI: 4.62, 1.67-12.77; p = 0.003) than those who did not (n = 183). The median time to loss of function was 1.93 [IQR; 0.77-3.19] years.

CONCLUSIONS

Donor CYP3A5 expressor status is associated with worse renal graft survival and a higher risk of acute rejection. Determination of donor CYP3A5 genotype is a potentially useful tool that may improve kidney transplant outcomes.

Stimulatory and Inhibitory Effects of Steroid Hormones and Human Cytochrome P450 (CYP) 3A Inhibitors on Cortisol 6β-Hydroxylation Catalyzed by CYP3A Subfamilies

OBJECTIVE

The inhibitory and stimulatory effects of several compounds, including steroid hormones and azole antifungal agents, on cortisol 6β-hydroxylation activity by cytochrome P450 (CYP) 3A4, polymorphically expressed CYP3A5, and fetal CYP3A7 were compared with those on testosterone 6β-hydroxylation to clarify the catalytic properties of the predominant forms of the human CYP3A subfamily.

METHODS

6β-Hydroxylation activities of cortisol and testosterone by CYP3A4, CYP3A5, and CYP3A7 in the absence or presence of dehydroepiandrosterone (DHEA), α-naphthoflavone (ANF), ketoconazole, itraconazole, and voriconazole were measured using high-performance liquid chromatography.

RESULTS

Lower concentrations of DHEA and ANF increased cortisol 6β-hydroxylation activities catalyzed by CYP3A4 but not those catalyzed by CYP3A5 and CYP3A7. The inhibition strength of azole antifungal agents against cortisol 6β-hydroxylation catalyzed by all CYP3A subfamilies was similar to that of testosterone 6β-hydroxylation. Although the Michaelis constant (Km) increased 2-fold in the presence of 20 μM DHEA compared to that of the control, the maximal velocity (Vmax) values gradually increased with increasing DHEA. For ANF, both Km and Vmax values increased, although the Km value decreased at 2.5 μM concentrations. Ketoconazole and itraconazole competitively inhibited cortisol 6β-hydroxylation mediated by CYP3A4 with similar inhibition constants.

CONCLUSION

The inhibitory/stimulatory pattern among CYP3A subfamily members differed between cortisol and testosterone, and CYP3A4 was found to be the most sensitive in terms of inhibition by azole antifungals among the CYP3A subfamily members investigated.

Influence of CYP3A4*22 and CYP3A5*3 combined genotypes on tacrolimus dose requirements in Egyptian renal transplant patients

BACKGROUND

Tacrolimus is a widely prescribed immunosuppressant agent for kidney transplantation. However, optimal dosing is challenging due to its narrow therapeutic index, potentially serious adverse effects, and wide inter-individual variability in pharmacokinetics. Cytochrome P450 3A (CPY3A) enzymes metabolize tacrolimus, so allelic variants such as CYP3A4*22 and CYP3A5*3 may contribute to individual differences in pharmacokinetics and therapeutic efficacy of tacrolimus. This study assessed the frequency and influences of CYP3A4*22 and CYP3A5*3 genotypes, alone and combined, on tacrolimus pharmacokinetics and dose requirements in Egyptian kidney transplant patients.

METHODS

This is a prospective multicenter observational cohort study. Patients were genotyped for the CYP3A4*22 (rs35599367), and CYP3A5*3 (rs776746). Tacrolimus dose (mg), through blood level (ng/ml), and dose-adjusted trough concentration (C0/D) (ng/ml per mg/kg) were recorded during the first and third months post-transplantation and compared among genotype groups.

RESULTS

The CYP3A4*22 allele was rare (3.2% of subjects) while the CYP3A5*3 allele was widespread (90.38%) in this cohort. At the third month post-transplantation, median C0/D was significantly higher among CYP3A4*22 carriers than CYP3A4*1/*1 (146.25 [100-380] versus 85.57 [27-370] ng/ml per mg/kg, p = 0.028). Patients harbouring the one copy of the CYP3A4*22 allele and the CYP3A5*3/*3 genotype (n = 5) were classified as poor tacrolimus metabolizers, the CYP3A5*3/*3 plus CYP3A4*1/*1 genotype as intermediate metabolizers (n = 60), and the CYP3A4*1/*1 plus CYP3A5*1/*1 genotype as normal metabolizers (n = 13). During the first month post-transplantation, C0/D was significantly greater in poor metabolizers (113.07 ng/ml per mg/kg) than intermediate and normal metabolizers (90.380 and 49.09 ng/ml per mg/kg) (p < 0.0005). This rank order was also observed during the third month. Acute rejection rate and renal function at discharge did not differ among genotypes.

CONCLUSION

Pharmacogenetics testing for CYP3A4*22 and CYP3A5*3 before renal transplantation may help in the adjustment of tacrolimus starting dose and identify patients at risk of tacrolimus overexposure or underexposure.

Influence of CYP3A5, IL-10 polymorphisms and metabolism rate on tacrolimus exposure in renal post-transplant recipients

Aim: To investigate the influence of CYP3A5 and IL-10 polymorphisms on tarcolimus metabolism and renal function for renal transplantation recipients at a stable period. Methods: CYP3A5 and IL-10 polymorphisms, together with other clinical factors, were collected for 149 renal transplantation patients at postoperative stable period. Statistics analysis was performed to explore key factors affecting tarcolimus metabolism. Results: CYP3A5 6986A >G and IL-10 -819C >T significantly impacted tacrolimus metabolism (p < 0.001). CYP3A5 6986A >G G allele and IL-10 -819C >T T allele were associated with poorer tacrolimus metabolic capability. Patients with various tacrolimus metabolism rates presented little difference in renal functions at stable period. Conclusion: Genotyping of CYP3A5 and IL-10 might benefit the precision dosage of tacrolimus for renal transplantation recipients.

Comparison of Tacrolimus Intra-Patient Variability during 6-12 Months after Kidney Transplantation between CYP3A5 Expressers and Nonexpressers

A high intra-patient variability (IPV) of tacrolimus exposure is associated with poor long-term kidney transplantation outcomes. To assess the influence of cytochrome P450 (CYP) 3A5 genetic polymorphisms on tacrolimus IPV, 188 clinically stable kidney transplant recipients, who had received an immediate-release tacrolimus-based immunosuppressive regimen, were enrolled in this retrospective cohort study. Genotyping of CYP3A5*3 (rs776746) was performed and 110 (58.5%) were identified as CYP3A5 expressers and 78 (41.5%) as nonexpressers. Whole blood tacrolimus concentrations were analyzed by chemiluminescent microparticle immunoassay. Dose-adjusted trough tacrolimus concentrations (C0/D) measured at months 6, 9, and 12 were used to determine IPV. There were no significant differences in the IPV estimated by the coefficient of variation, the IPV calculated by mean absolute deviation method, and the proportions of recipients with the IPV estimated by the coefficient of variation of 30% or more between CYP3A5 expressers and nonexpressers (p = 0.613, 0.686, and 0.954, respectively). Tacrolimus C0/D in CYP3A5 expressers was approximately half of those in nonexpressers, overall (p < 0.001). In both CYP3A5 expressers and nonexpressers, tacrolimus C0/D increased gradually from month 6 to month 12 (p = 0.021). There was no evidence that the CYP3A5 polymorphisms significantly influence tacrolimus IPV during the 6 to 12 months after kidney transplantation.

Cytochrome P450 oxidoreductase variant A503V contributes to the increased CYP3A5 activity with tacrolimus in vitro

BACKGROUND

Tacrolimus is a calcineurin inhibitor with a strong efficacy in prevention of graft rejection after transplantation. It is well known that cytochrome P450 3A5 (CYP3A5) has a high metabolic capacity for tacrolimus, and mutations in human cytochrome P450 oxidoreductase (POR) cause altered CYP3A5 activity. Recently, clinical studies have revealed that POR*28 contributes enhanced tacrolimus clearance in CYP3A5 expressers. A503V is an amino acid sequence variant encoded by POR*28. In this study, we first evaluated the impact of A503V on CYP3A5 activity with tacrolimus as the substrate in vitro.

RESEARCH DESIGN & METHODS

Wild-type (WT) and A503V POR, with WT CYP3A5 were expressed in recombinant HepG2 cells and reconstituted proteins. Michaelis constant (K_m) and maximum velocity (V_max) of CYP3A5 with tacrolimus as substrates were determined, and catalytic efficiency is expressed as V_max/K_m.

RESULTS

WT and A503V POR both down-regulated the CYP3A5 mRNA expression, and WT POR rather than A503V down-regulated the protein expression of CYP3A5 in recombinant HepG2 cells. Compared with WT POR, A503V increased metabolism of tacrolimus by CYP3A5 in both cellular and protein level.

CONCLUSION

A503V can affect CYP3A5-catalyzed tacrolimus metabolism in vitro, which suggests that A503V has the potential to serve as a biomarker for tacrolimus treatment in transplantation recipients.

Mechanism-based inhibition of CYP3A subfamilies by macrolide antibiotics and piperine

OBJECTIVE

The mechanism-based inhibition of macrolide antibiotics, such as erythromycin and clarithromycin, and piperine on testosterone 6β-hydroxylation activities by cytochrome P450 (CYP) 3A4, polymorphically expressed CYP3A5, and fetal CYP3A7 were compared.

METHODS

6β-Hydroxy testosterone was determined by high-performance liquid chromatography.

RESULTS

Although preincubation with erythromycin and clarithromycin decreased CYP3A4-meditaed testosterone 6β- hydroxylation in a time-dependent manner, and the estimated maximum inactivation rate constant (k inact ) and the inactivation rate constant reaching half of k inact (K i ) for erythromycin were approximately 1/2 and 1/5, respectively, of those for clarithromycin. Obvious preincubation time-dependent inhibition of erythromycin against CYP3A5 and CYP3A7 was not observed. Piperine exhibited preincubation time- dependent inhibition, and the calculated K i and k inact values for CYP3A4 were approximately 1/7 and 1/2, respectively, of those for CYP3A5.

CONCLUSION

It is speculated that the preincubation-dependent inhibition by piperine would be more potent in CYP3A5 non-expressors than CYP3A5-expressors.

CYP3A5*3 and SLCO1B1 c.521T>C Polymorphisms Influence the Pharmacokinetics of Atorvastatin and 2-Hydroxy Atorvastatin

There is a large variability in individual responses to atorvastatin administration. This study assessed the pharmacogenetic effects of solute carrier organic anion transporter family member 1B1 (SLCO1B1, c.388A>G and c.521T>C) and cytochrome P450 3A5 (CYP3A5, CYP3A5*3) genetic polymorphisms on the pharmacokinetics of atorvastatin and its active metabolite, 2-hydroxy (2-OH) atorvastatin, in 46 individuals who were administered a clinically used single oral dosage of 80 mg. The Cmax and AUC of atorvastatin in CYP3A5*3/*3 carriers were 2.6- and 2.8-fold higher, respectively, than those in CYP3A5*1/*1 carriers, and similar results were observed for 2-OH atorvastatin pharmacokinetics. SLCO1B1 c.521T>C also increased the AUC of atorvastatin and 2-OH atorvastatin. The AUC ratio of atorvastatin and 2-OH atorvastatin were not affected by SLCO1B1 c.388A>G or c.521T>C, whereas CYP3A5*3 reduced the AUC ratio. In an analysis evaluating the simultaneous effect of the SLCO1B1 c.521T>C and CYP3A5*3 polymorphisms, SLCO1B1 c.521TT/CYP3A5*1/*1 carriers showed lower Cmax and AUC values for atorvastatin and 2-OH atorvastatin than in individuals with the SLCO1B1 c.521T>C and/or CYP3A5*3 genotypes. Among the participants with the SLCO1B1 c.521TT genotype, the CYP3A5*3 carriers had a higher systemic exposure to atorvastatin and 2-OH atorvastatin than the CYP3A5*1/*1 carriers. Thus, SLCO1B1 c.521T>C and CYP3A5*3 polymorphisms affect the pharmacokinetics of atorvastatin and 2-OH atorvastatin.

Analysis of pharmacogenomic very important pharmacogenomic variants: CYP3A5, ACE, PTGS2 and NAT2 genes in Chinese Bai population

Aim: Our study aimed to screen the genotype frequencies of very important pharmacogenomic (VIP) mutations and identify their differences between Bai and other populations. Materials & methods: We selected 66 VIP variants from PharmGKB (www.pharmgkb.org/) for genotyping. χ2 test was used to identify differences in loci between these populations and Fst values of Bai and the other 26 populations were analyzed. Results: Our study showed that the frequencies of SNPs of CYP3A5, ACE, PTGS2 and NAT2 differed significantly from those of the other 26 populations. At the same time, we found that some VIP variants may affect the metabolism of drugs and the genetic relationship between the Bai population and East Asian populations was found to be the closest. Conclusion: By comparing the genotype frequencies of different populations, the loci with significant differences were identified and discussed, providing a theoretical basis for individualized drug use in the Bai ethnic population.

CYP3A and CYP2B6 Genotype Predicts Glucose Metabolism Disorder among HIV Patients on Long-Term Efavirenz-Based ART: A Case-Control Study

Long-term antiretroviral treatment (cART) increases the risk of glucose metabolism disorders (GMDs). Genetic variation in drug-metabolizing enzymes and transporters may influence susceptibility to cART-associated GMDs. We conducted a case-control study to investigate the association of pharmacogenetic variations with cART-induced GMDs. A total of 240 HIV patients on long-term efavirenz-based cART (75 GMD cases and 165 controls without GMDs) were genotyped for CYP3A4*1B, CYP3A5 (*3,*6), CYP2B6*6, UGT2B7*2, ABCB1 (c.3435C>T, c.4036A>G), and SLCO1B1 (*1b, *5). GMD cases were defined as the presence of impaired fasting glucose, insulin resistance, or diabetes mellitus (DM). Case-control genotype/haplotype association and logistic regression analysis were performed by adjusting for age, sex, and BMI. The major CYP3A haplotype were CYP3A5*3 (53.8%), CYP3A4*1B (17.3%), combinations of CYP3A4*1B, and CYP3A5*6 (10.9%), and CYP3A wild type (7%). CYP3A5*6 allele (p = 0.005) and CYP3A5*6 genotype (p = 0.01) were significantly associated with GMD cases. Multivariate analysis indicated CYP3A haplotype as a significant predictor of GMD (p = 0.02) and IFG (p = 0.004). CYP2B6*6 significantly predicted DM (p = 0.03). CYP3A haplotype and CYP2B6*6 genotype are independent significant predictors of GMD and DM, respectively, among HIV patients on long-term EFV-based cART.

The importance of CYP2C19 genotype in tacrolimus dose optimization when concomitant with voriconazole in heart transplant recipients

AIMS

Voriconazole remains the mainstay for the treatment of invasive fungal infections in the heart transplant patients and can significantly increase tacrolimus exposure because of drug-drug interaction (DDI). However, the magnitude of this DDI is highly variable and difficult to predict. The purpose of this study was to present the characteristics of DDI between tacrolimus and voriconazole, and further identify the various predictors of tacrolimus dose modification.

METHODS

We retrospectively enrolled 69 heart transplant recipients without using voriconazole as the control and 68 patients received voriconazole treatment in voriconazole group. CYP3A4*1G, CYP3A5*3 and CYP2C19*2 or *3 were thereafter genotyped by Sanger sequencing. The requirement of tacrolimus dose to achieve the therapeutic concentrations and tacrolimus dose-corrected trough concentration (C₀ /D) before and after VRC administration were evaluated.

RESULTS

The DDI between tacrolimus and voriconazole displayed a large inter-individual variability with more than ten-fold changes in tacrolimus dose (range 1.28-13.00) and C₀ /D (range 1.43-13.75). Besides, the fold changes of tacrolimus dose were associated with CYP2C19 genotype, which was found to be significantly lower in CYP2C19 extensive metabolizers than that in CYP2C19 intermediate metabolizers or poor metabolizers (4.06±1.85 vs 5.49±2.47, p=0.0031). However, no significant difference was found in both CYP3A4 and CYP3A5 genotypes. Moreover, CYP2C19 genotype and hematocrit acted as independent predicting factors for tacrolimus dose modification after voriconazole co-therapy.

CONCLUSIONS

The findings of this study have identified the various important factors to adjust tacrolimus dosage when co-administrated with voriconazole in individual patients. CYP2C19 genotype and hematocrit should be considered in tailoring tacrolimus dose.

Structural characterization of the homotropic cooperative binding of azamulin to human cytochrome P450 3A5

Cytochrome P450 3A4 and 3A5 catalyze the metabolic clearance of a large portion of therapeutic drugs. Azamulin is used as a selective inhibitor for 3A4 and 3A5 to define their roles in metabolism of new chemical entities during drug development. In contrast to 3A4, 3A5 exhibits homotropic cooperativity for the sequential binding of two azamulin molecules at concentrations used for inhibition. To define the underlying sites and mechanisms for cooperativity, an X-ray crystal structure of 3A5 was determined with two azamulin molecules in the active site that are stacked in an antiparallel orientation. One azamulin resides proximal to the heme in a pose similar to the 3A4-azamulin complex. Comparison to the 3A5 apo structure indicates that the distal azamulin in 3A5 ternary complex causes a significant induced fit that excludes water from the hydrophobic surfaces of binding cavity and the distal azamulin, which is augmented by the stacking interaction with the proximal azamulin. Homotropic cooperativity was not observed for the binding of related pleuromutilin antibiotics, tiamulin, retapamulin, and lefamulin, to 3A5, which are larger and unlikely to bind in the distal site in a stacked orientation. Formation of the 3A5 complex with two azamulin molecules may prevent time-dependent inhibition that is seen for 3A4 by restricting alternate product formation and/or access of reactive intermediates to vulnerable protein sites. These results also contribute to a better understanding of sites for cooperative binding and the differential structural plasticity of 3A5 and 3A4 that contribute to differential substrate and inhibitor binding.

Rapid clearance of tacrolimus blood concentration triggered by variant pharmacogenes

WHAT IS KNOWN AND OBJECTIVE

Tacrolimus (TAC) is an immunosuppressant with large interpatient pharmacokinetic variability and a narrow therapeutic index. We report a case of acute cellular rejection (ACR) type IB with insufficient TAC blood concentrations (TAC C₀ ).

CASE SUMMARY

ACR developed on the eighth postoperative day of kidney transplantation. During this period, TAC C₀ were insufficient. This referred pharmacogenetic assessment disclosed the patient as a CYP3A5 expresser and CYP3A4*1B carrier. According to the genotype, higher doses of TAC, 15 mg twice daily, were administered and targeted TAC C₀ were achieved.

WHAT IS NEW AND CONCLUSION

Our case presents an association of TAC rapid clearance and two alleles modifying greater CYP3A enzyme activity.

Pharmacogenomic prescribing opportunities in percutaneous coronary intervention and bone marrow transplant patients

Aim: To evaluate the potential impact of preemptive multigene pharmacogenomic (PGx) testing on medication prescribing in real-world clinical settings. Patients & methods: Prescription frequencies for 65 medications with actionable PGx recommendations were collected in 215 percutaneous coronary intervention (PCI) and 131 allogeneic hematopoietic cell transplant (allo-HCT) patients. A simulation projected the number of PGx-guided prescribing opportunities. Results: In PCI and allo-HCT patients, respectively, 66.5 and 90.1% were prescribed at least one medication with actionable PGx prescribing recommendations. Simulations projected 26.5 and 41.2 total PGx-guided prescribing opportunities per 100 PCI and allo-HCT patients, respectively, if multigene PGx results were available. Conclusion: A multigene PGx testing strategy offers potential to optimize medication prescribing beyond clopidogrel and tacrolimus in PCI and allo-HCT patients.

Cytochrome P450 3A5 polymorphism affects the metabolism of sorafenib and its toxicity for hepatocellular carcinoma cells in vitro

OBJECTIVE

Cytochrome P450 3A5 (CYP3A5) is a highly polymorphic gene and the encoded protein variants differ in catalytic activity, leading to inter-individual variation in metabolic ability. The aim of the current study was to investigate the effects of seven allelic variants on the ability of CYP3A5 to metabolize sorafenib in vitro and further explore the impacts of CYP3A5 polymorphism on the proliferation and apoptosis of hepatocellular carcinoma cell line (HepG2) induced by sorafenib.

METHODS

Wild-type and variant CYP3A5 enzymes were expressed in Spodoptera frugiperda insect cells using a baculovirus dual-expression system, and protein expression was checked by western blot. The enzymes were incubated with sorafenib at 37°C for 30 min, and formation of the major metabolite sorafenib N-oxide was assayed using ultra-performance liquid chromatography and tandem mass spectrometry. Intrinsic clearance values (V_max/K_m) were calculated for each enzyme. Additionally, recombinant HepG2 cells transfecting with CYP3A5 variants were used to investigate the effects of sorafenib on the proliferation of HepG2 cells.

RESULTS

Intrinsic clearance of the six variants CYP3A5*2, CYP3A5*3A, CYP3A5*3C, CYP3A5*4, CYP3A5*5, and CYP3A5*7 was 26.41-71.04% of the wild-type (CYP3A5*1) value. In contrast, the clearance value of the variant CYP3A5*6 was significantly higher (174.74%). Additionally, the decreased ATP levels and cell viability and the increased cell apoptosis in HepG2 cells transfected with CYP3A5*2, CYP3A5*3A, CYP3A5*3C, CYP3A5*4, CYP3A5*5, and CYP3A5*7 were observed, whereas, the increased ATP levels and cell viability and the reduced cell apoptosis in HepG2 cells transfected with CYP3A5*6 were also investigated when compared to CYP3A5*1.

CONCLUSION

Our results suggest that CYP3A5 polymorphism influences sorafenib metabolism and pharmacotherapeutic effect in hepatic carcinomas. These data may help explain differential response to drug therapy for hepatocellular carcinoma, and they support the need for individualized treatment.

CYP3A7, CYP3A4, and CYP3A5 genetic polymorphisms in recipients rather than donors influence tacrolimus concentrations in the early stages after liver transplantation

AIM

The purpose of this study was to investigate the effect of CYP3A7, CYP3A4, and CYP3A5 genetic polymorphisms in liver transplant recipients and donors on tacrolimus concentrations in the early stages after liver transplantation.

METHODS

One hundred and thirty-eight liver transplant recipients and matched donors were genotyped for CYP3A7 (rs10211 and rs2257401), CYP3A4 (rs4646437 and rs2242480), and CYP3A5*3 (rs776746) polymorphisms. The relationships between dose-adjusted trough concentrations (C₀/D) of tacrolimus and corresponding genotypes were investigated.

RESULTS

Recipient CYP3A polymorphisms were associated with tacrolimus concentrations. The CYP3A7 rs10211 AA carriers (186.2 vs 90.5, p < 0.001), CYP3A4 rs4646437 CC carriers (184.0 vs 88.8, p < 0.001), CYP3A4*1G rs2242480 CC carriers (189.8 vs 99.7, p < 0.001), and CYP3A5*3 rs776746 GG carriers (197.3 vs 86.0, p < 0.001) had an almost twofold increase in the tacrolimus C₀/D compared to that of the non-carriers. We further investigated the effect of the combination of recipient (intestinal) and donor (hepatic) genotypes on tacrolimus concentrations. Regardless of the genotype of the matched donor, CYP3A7 rs10211, CYP3A4*1G (rs2242480), and CYP3A5*3 (rs776746) polymorphisms of recipients could affect tacrolimus concentrations. For the CYP3A4 rs4646437 polymorphisms, when the donor carried CYP3A4 rs4646437 CC, the recipient CYP3A4 rs4646437 polymorphism was associated with the C₀/D of tacrolimus, and when the donor carried CYP3A4 rs4646437 CT/TT genotype, the recipient CYP3A4 rs4646437 polymorphism also affected on tacrolimus C₀/D, although the effect was not significant.

CONCLUSION

The large inter-individual variation in tacrolimus concentrations in the early stages after liver transplantation is influenced by genetic polymorphisms of CYP3A7, CYP3A4, and CYP3A5. Recipient (intestinal) CYP3A7, CYP3A4, and CYP3A5 polymorphisms seem to contribute more to such variation than donors. Therefore, the detection of CYP3A polymorphisms in recipients could help to predict the tacrolimus starting dose in the early stages after liver transplantation.

Pharmacogenomics of Vincristine-Induced Peripheral Neuropathy in Children with Cancer: A Systematic Review and Meta-Analysis

Simple Summary

Vincristine is a drug that is part of the treatment for many children with cancer. Its main side-effect is vincristine-induced peripheral neuropathy (VIPN), which often presents as tingling, pain, and lack of strength in the hands and feet. It is not yet possible to predict which children will suffer from VIPN. In this review, we report on all genetic variations that are associated with VIPN. We found that variations in genes related to vincristine transport, cell structure, hereditary nerve disease, and genes without a previously known connection to vincristine or VIPN are related to VIPN. Variations in genes involved in vincristine breakdown are not significantly associated with VIPN. In conclusion, genetic variations affect a child’s tendency to develop VIPN. In the future, this information might be used to predict the risk of VIPN and adapt treatment on this.

Abstract

Vincristine-induced peripheral neuropathy (VIPN) is a debilitating side-effect of vincristine. It remains a challenge to predict which patients will suffer from VIPN. Pharmacogenomics may explain an individuals’ susceptibility to side-effects. In this systematic review and meta-analysis, we describe the influence of pharmacogenomic parameters on the development of VIPN in children with cancer. PubMed, Embase and Web of Science were searched. In total, 1597 records were identified and 21 studies were included. A random-effects meta-analysis was performed for the influence of CYP3A5 expression on the development of VIPN. Single-nucleotide polymorphisms (SNPs) in transporter-, metabolism-, cytoskeleton-, and hereditary neuropathy-associated genes and SNPs in genes previously unrelated to vincristine or neuropathy were associated with VIPN. CYP3A5 expression status was not significantly associated with VIPN. The comparison and interpretation of the results of the included studies was limited due to heterogeneity in the study population, treatment protocol and assessment methods and definitions of VIPN. Independent replication is essential to validate the clinical significance of the reported associations. Future research should aim for prospective VIPN assessment in both a discovery and a replication cohort. Ultimately, the goal would be to screen patients upfront to determine optimal vincristine dosage with regards to efficacy and risk of VIPN.

Association between gene polymorphism and adverse effects in cancer patients receiving docetaxel treatment: a meta-analysis

PURPOSE

Large interindividual variability in the pharmacokinetic properties of docetaxel has been reported, with the clearance of docetaxel varying nearly six fold, in which pharmacogenetics of docetaxel may play an essential role in addition to physiological factors. The association between the gene polymorphism and risk of adverse clinical effects in docetaxel treated patients has been examined in several studies, but their conclusions are, to some extent, controversial. To clarify the role of gene polymorphism in the clinical outcomes of docetaxel treatment, a meta-analysis was performed in the present study.

METHODS

Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were employed to evaluate the impact of gene polymorphisms of CYP3A4, CYP3A5 and ABCB1. Four studies with 485 subjects were included in this study. Fixed or random-effects model was chosen according to heterogeneity to conduct the meta-analysis. Publication bias was evaluated by fail-safe numbers.

RESULTS

Significant association was identified between the ABCB1 C3435T (rs1045642) polymorphism and risk of short-term recurrent hematological toxicity (TT vs. CC + TC OR = 2.91, 95% CI 1.30-6.52, P = 0.009; TT vs. CC OR = 4.23, 95% CI 1.69-10.57 P = 0.002). The association of the ABCB1 G2677T/A (rs2032582) polymorphism with risk of fluid retention was statistically significant (T(A)/T(A) vs. GG + GT(A) OR = 2.08, 95% CI 1.16-3.73, P = 0.01). No statistically significant association between the CYP3A5 A6986G (rs776746) polymorphism and adverse effects was observed in this study. Due to the limitations of included literature, we did not conduct meta-analysis on CYP3A4 gene polymorphism and adverse effects.

CONCLUSION

An association between the ABCB1 C3435T (rs1045642), ABCB1 G2677T/A (rs2032582) polymorphism and risk of adverse effects of docetaxel was found by our meta-analysis. Namely, the TT homozygotes of the ABCB1 C3435T polymorphism may be associated with the risk of hematological toxicity. ABCB1 G2677T T(A)/T(A) genotype may be associated with the fluid retention.

TRAIL REGISTRATION

PROSPERO 2020 CRD42020203132.