Impact of CYP2C19, CYP3A4, ABCB1, and FMO3 genotypes on plasma voriconazole in Thai patients with invasive fungal infections

A type of self-assembled and label-free DNA-modified electrochemical biosensors based on magnetic α-Fe2O3/Fe3O4 heterogeneous nanorods for ultra-sensitive detection of CYP2C19*3

CYP2C19*3 enzyme plays a pivotal role in drug metabolism and is tightly regulated by the CYP2C19*3 gene. Therefore, quantification of CYP2C19*3 gene holds paramount importance for achieving personalized medication guidance in precision medicine. In this project, the magnetic electrochemical biosensors were constructed for the ultra-sensitive detection of CYP2C19*3 gene. Employing magnetic α-Fe2O3/Fe3O4@Au as the matrixes for signal amplification, CYP2C19*3 complementary chains (c-ssDNA) were bound to their surfaces through gold-sulfur bonds with subsequent specific sites blockade by bovine serum albumin (BSA) to form the α-Fe2O3/Fe3O4@Au/c-ssDNA/BSA biosensors. This design enabled efficient biosensors separation, target gene capture, and self-assembly on the electrode surface, enhancing the response signal. The biosensors exhibited excellent capture capabilities with a wide linear range (1 pM-1 μM), a low detection limit of 0.2710 pM, a quantitation limit of 0.9033 pM, reproducibility with an RSD value of 1.26 %, and stable storage for at least one week. The RSD value of CYP2C19*3 in serum samples consistently remained below 4.5 %, with a recovery rate ranging 95.52 % from 102.71 %. Moreover, the target gene could be accurately identified and captured in a mixed system of multiple nucleotide mutants of the CYP2C19*3 gene, suggesting a promising applicability and popularization.

Impact of CYP2C19, CYP2C9, CYP3A4, and FMO3 Genetic Polymorphisms and Sex on the Pharmacokinetics of Voriconazole after Single and Multiple Doses in Healthy Chinese Subjects

Voriconazole is the first-line treatment for invasive aspergillosis. Its pharmacokinetics exhibit considerable inter- and intra-individual variability. The purpose of this study was to investigate the effects of CYP2C19, CYP2C9, CYP3A4, and FMO3 genetic polymorphisms and sex on the pharmacokinetics of voriconazole in healthy Chinese adults receiving single-dose and multiple-dose voriconazole, to provide a reference for its clinical individualized treatment. A total of 123 healthy adults were enrolled in the study, with 108 individuals and 15 individuals in the single-dose and multiple-dose doses, respectively. Plasma voriconazole concentrations were measured using a validated LC-MS/MS method, and pharmacokinetics parameters were calculated using the non-compartmental method with WinNonlin 8.2. CYP2C19, CYP2C9, CYP3A4, and FMO3 single-nucleotide polymorphisms were sequenced using the Illumina Hiseq X-Ten platform. The results suggested that CYP2C19 genetic polymorphisms significantly affected the pharmacokinetics of voriconazole at single doses of 4, 6, and 8 mg/kg and multiple doses of voriconazole. CYP3A4 rs2242480 had a significant effect on AUC0-∞ (area under the plasma concentration-time curve from time 0 to infinity) and MRT (mean residence time) of voriconazole at a single dose of 4 mg/kg in CYP2C19 extensive metabolizer. Regardless of the CYP2C19 genotype, CYP2C9 rs1057910 and FMO3 rs2266780 were not associated with the pharmacokinetics of voriconazole at three single-dose levels or multiple doses. No significant differences in most voriconazole pharmacokinetics parameters were noted between male and female participants after single and multiple dosing. For patients receiving voriconazole treatment, CYP2C19 genetic polymorphisms should be genotyped for its precision administration. In contrast, based on our study of healthy Chinese adults, it seems unnecessary to consider the effects of CYP2C9, CYP3A4, and FMO3 genetic polymorphisms on voriconazole pharmacokinetics.

Interaction of age and CYP2C19 genotypes on voriconazole steady-state trough concentration in Chinese patients

OBJECTIVES

Both age and CYP2C19 genotypes affect voriconazole plasma concentration; the interaction of age and CYP2C19 genotypes on voriconazole plasma concentration remains unknown. This study aims to investigate the combined effects of age and CYP2C19 genotypes on voriconazole plasma concentration in Chinese patients.

METHODS

A total of 480 patients who received voriconazole treatment were recruited. CYP2C19*2 (rs4244285) and CYP2C19*3 (rs4986893) polymorphisms were genotyped. Patients were divided into the young and the elderly groups by age of 60 years old. Influence of CYP2C19 genotype on steady-state trough concentration (C ss-min ) in overall patients and in age subgroups was analyzed.

RESULTS

Voriconazole C ss-min correlated positively with age, and mean voriconazole C ss-min was significantly higher in the elderly group ( P  < 0.001). CYP2C19 poor metabolizers showed significantly increased mean voriconazole C ss-min in the young but not the elderly group. The percentage of patients with subtherapeutic voriconazole C ss-min (<1.0 mg/l) was higher in the young group and that of supratherapeutic voriconazole C ss-min (>5.5 mg/l) was higher in the elderly patients. When the average C ss-min in the CYP2C19 normal metabolizer genotype was regarded as a reference, CYP2C19 genotypes showed greater impact on voriconazole C ss-min in the young group, while the influence of age on voriconazole C ss-min exceeded CYP2C19 genotypes in the elderly.

CONCLUSION

CYP2C19 genotypes affects voriconazole exposure is age dependent. Influence of CYP2C19 poor metabolizer genotype on increased voriconazoleexposure is prominent in the young, while age is a more important determinant factor for increased voriconazole exposure in the elderly patients.

Combined impact of hypoalbuminemia and pharmacogenomic variants on voriconazole trough concentration: data from a real-life clinical setting in the Chinese population

Voriconazole (VRC) displays highly variable pharmacokinetics impacting treatment efficacy and safety. To provide evidence for optimizing VRC therapy regimens, the authors set out to determine the factors impacting VRC steady-state trough concentration (Cmin) in patients with various albumin (Alb) level. A total of 275 blood samples of 120 patients and their clinical characteristics and genotypes of CYP2C19, CYP3A4, CYP3A5, CYP2C9, FMO3, ABCB1, POR, NR1I2 and NR1I3 were included in this study. Results of multivariate linear regression analysis demonstrated that C-reactive protein (CRP) and total bilirubin (T-Bil) were predictors of the VRC Cmin adjusted for dose in patients with hypoalbuminemia (Alb < 35 g/L) (R2 = 0.16, P < 0.001). Additionally, in patients with normal albumin level (Alb ≥ 35 g/L), it resulted in a significant model containing factors of the poor metabolizer (PM) CYP2C19 genotype and CRP level (R2 = 0.26, P < 0.001). Therefore, CRP and T-Bil levels ought to receive greater consideration than genetic factors in patients with hypoalbuminemia.

Individualized treatment with voriconazole in the Chinese population: Inflammation level as a novel marker for dose optimization

AIMS

The aim of this study was to explore the influence and possible mechanisms of pharmacokinetics-related gene polymorphisms, especially CYP2C19 polymorphisms, and non-genetic factors combined with the inflammatory status on the voriconazole (VRC) metabolism of the Chinese population.

METHODS

Clinical studies were performed by collecting more than one VRC trough concentration and C-reactive protein (CRP) level. A total of 265 blood samples were collected from 120 patients.

RESULTS

Results of multiple regression analyses demonstrated that CYP2C19 genotypes and albumin (Alb) level remained predictors of Cmin ss/D in patients with no to mild inflammation (R2  = 0.12, P < .001). In addition, in patients with moderate to severe inflammation, it resulted in a significant model containing factors of CRP and total bilirubin (T-Bil) levels (R2  = 0.19, P < .001). In non-clinical studies, 32 rats were divided into control and inflammatory groups, and it was found that the mean residence time (MRT(0-t) ) of VRC in the inflammatory group was significantly longer than that in the control group (P < .001), which may be due to down-regulation of mRNA and protein expression of CYP2C19 (CYP2C6 in rats) through interleukin (IL)-6/signal transducer and activator of transcription (STAT) 3 pathway.

CONCLUSIONS

Therefore, the effect of CYP2C19 polymorphisms on VRC metabolism may be masked by inflammatory status, which should be of more concern than CYP2C19 polymorphisms in patients with moderate to severe inflammation. Additionally, the impact of Alb and T-Bil on VRC metabolism should not be disregarded.

Pharmacogenetic and clinical predictors of voriconazole concentration in hematopoietic stem cell transplant recipients receiving CYP2C19-guided dosing

CYP2C19-guided voriconazole dosing reduces pharmacokinetic variability, but many patients remain subtherapeutic. The aim of this study was to evaluate the effect of candidate genes and a novel CYP2C haplotype on voriconazole trough concentrations in patients receiving CYP2C19-guided dosing. This is a retrospective candidate gene study in allogeneic hematopoietic cell transplant (HCT) patients receiving CYP2C19-guided voriconazole dosing. Patients were genotyped for ABCB1, ABCG2, CYP2C9, CYP3A4, CYP3A5, and the CYP2C haplotype. Of 185 patients, 36% were subtherapeutic (of which 79% were normal or intermediate metabolizers). In all patients, CYP2C19 (p < 0.001), age (p = 0.018), and letermovir use (p = 0.001) were associated with voriconazole concentrations. In the subset receiving 200 mg daily (non-RM/UMs), CYP2C19 (p = 0.004) and ABCG2 (p = 0.015) were associated with voriconazole concentrations; CYP2C19 (p = 0.028) and letermovir use (p = 0.001) were associated with subtherapeutic status. CYP2C19 phenotype and letermovir use were significantly associated with subtherapeutic voriconazole concentrations and may be used to improve voriconazole precision dosing, while further research is needed to clarify the role of ABCG2 in voriconazole dosing.

The impact of gene polymorphism and hepatic insufficiency on voriconazole dose adjustment in invasive fungal infection individuals

Voriconazole (VRZ) is a broad-spectrum antifungal medication widely used to treat invasive fungal infections (IFI). The administration dosage and blood concentration of VRZ are influenced by various factors, posing challenges for standardization and individualization of dose adjustments. On the one hand, VRZ is primarily metabolized by the liver, predominantly mediated by the cytochrome P450 (CYP) 2C19 enzyme. The genetic polymorphism of CYP2C19 significantly impacts the blood concentration of VRZ, particularly the trough concentration (Ctrough), thereby influencing the drug's efficacy and potentially causing adverse drug reactions (ADRs). Recent research has demonstrated that pharmacogenomics-based VRZ dose adjustments offer more accurate and individualized treatment strategies for individuals with hepatic insufficiency, with the possibility to enhance therapeutic outcomes and reduce ADRs. On the other hand, the security, pharmacokinetics, and dosing of VRZ in individuals with hepatic insufficiency remain unclear, making it challenging to attain optimal Ctrough in individuals with both hepatic insufficiency and IFI, resulting in suboptimal drug efficacy and severe ADRs. Therefore, when using VRZ to treat IFI, drug dosage adjustment based on individuals' genotypes and hepatic function is necessary. This review summarizes the research progress on the impact of genetic polymorphisms and hepatic insufficiency on VRZ dosage in IFI individuals, compares current international guidelines, elucidates the current application status of VRZ in individuals with hepatic insufficiency, and discusses the influence of CYP2C19, CYP3A4, CYP2C9, and ABCB1 genetic polymorphisms on VRZ dose adjustments and Ctrough at the pharmacogenomic level. Additionally, a comprehensive summary and analysis of existing studies' recommendations on VRZ dose adjustments based on CYP2C19 genetic polymorphisms and hepatic insufficiency are provided, offering a more comprehensive reference for dose selection and adjustments of VRZ in this patient population.

Association of CYP2C19, CYP3A4 and ABCC2 polymorphisms and voriconazole plasma concentrations in Uygur pediatric patients

Aim: To evaluate the association between CYP2C19, CYP3A4 and ABCC2 polymorphisms and voriconazole plasma concentrations in Uygur pediatric patients with allogeneic hematopoietic stem cell transplantation. Materials & methods: High performance liquid chromatography-mass spectrometry was employed to monitor voriconazole concentrations. First-generation sequencing was performed to detect gene polymorphisms. Results: Voriconazole concentrations of normal metabolizers were significantly higher than those of intermediate (p < 0.05) and ultrafast (p < 0.001) metabolizers. Patients with ABCC2 GG and GA genotypes exhibited significantly lower voriconazole concentrations compared with patients with the AA genotype (p < 0.05). Conclusion: These results demonstrate a significant association between voriconazole concentrations and the CYP2C19 phenotype in Uygur pediatric patients with allogeneic hematopoietic stem cell transplantation.

Pharmacogenetic Aspects of Drug Metabolizing Enzymes and Transporters in Pediatric Medicine: Study Progress, Clinical Practice and Future Perspectives

As the activity of certain drug metabolizing enzymes or transporter proteins can vary with age, the effect of ontogenetic and genetic variation on the activity of these enzymes is critical for the accurate prediction of treatment outcomes and toxicity in children. This makes pharmacogenetic research in pediatrics particularly important and urgently needed, but also challenging. This review summarizes pharmacogenetic studies on the effects of genetic polymorphisms on pharmacokinetic parameters and clinical outcomes in pediatric populations for certain drugs, which are commonly prescribed by clinicians across multiple therapeutic areas in a general hospital, organized from those with the most to the least pediatric evidence among each drug category. We also further discuss the research status of the gene-guided dosing regimens and clinical implementation of pediatric pharmacogenetics. More and more drug-gene interactions are demonstrated to have clinical validity for children, and pharmacogenomics in pediatrics have shown evidence-based benefits to enhance the efficacy and precision of existing drug dosing regimens in several therapeutic areas. However, the most important limitation to the implementation is the lack of high-quality, rigorous pediatric prospective clinical studies, so adequately powered interventional clinical trials that support incorporation of pharmacogenetics into the care of children are still needed.

Pharmacogenomics in Asians: Differences and similarities with other human populations

INTRODUCTION

Various pharmacogenomic (PGx) variants differ widely in different ethnicities. and clinical outcomes associated with these variants may also be substantially varied. Literature was searched in different databases, i.e. PubMed, ScienceDirect, Web of Science, and PharmGKB, from inception to 30 June 2022 for this review.

AREAS COVERED

Certain PGx variants were distinctly varied in Asian populations compared to the other human populations, e.g. CYP2C19*2,*3,*17; CYP2C9*2,*3; CYP2D6*4,*5,*10,*41; UGT1A1*6,*28; HLA-B*15:02, HLA-B*15:21, HLA-B*58:01, and HLA-A*31:01. However, certain other variants do not vary greatly between Asian and other ethnicities, e.g. CYP3A5*3; ABCB1, and SLCO1B1*5. As evident in this review, the risk of major adverse cardiovascular events (MACE) was much stronger in Asian patients taking clopidogrel and who inherited the CYP2C19 loss-of-function alleles, e.g. CYP2C19*2 and*3, when compared to the western/Caucasian patients. Additionally, the risk of carbamazepine-induced severe cutaneous adverse drug reactions (SCARs) for the patients inheriting HLA-B*15:02 and HLA-B*15:21 alleles varied significantly between Asian and other ethnicities. In contrast, both Caucasian and Asian patients inheriting the SLCO1B1*5 variant possessed a similar magnitude of muscle toxicity, i.e. myopathy.

EXPERT OPINION

Asian countries should take measures toward expanding PGx research, as well as initiatives for the purposes of obtaining clinical benefits from this newly evolving and economically viable treatment model.

Pharmacogenetic Analysis of Voriconazole Treatment in Children

Voriconazole is among the first-line antifungal drugs to treat invasive fungal infections in children and known for its pronounced inter- and intraindividual pharmacokinetic variability. Polymorphisms in genes involved in the metabolism and transport of voriconazole are thought to influence serum concentrations and eventually the therapeutic outcome. To investigate the impact of these genetic variants and other covariates on voriconazole trough concentrations, we performed a retrospective data analysis, where we used medication data from 36 children suffering from invasive fungal infections treated with voriconazole. Data were extracted from clinical information systems with the new infrastructure SwissPK^cdw, and linear mixed effects modelling was performed using R. Samples from 23 children were available for DNA extraction, from which 12 selected polymorphism were genotyped by real-time PCR. 192 (49.1%) of 391 trough serum concentrations measured were outside the recommended range. Voriconazole trough concentrations were influenced by polymorphisms within the metabolizing enzymes CYP2C19 and CYP3A4, and within the drug transporters ABCC2 and ABCG2, as well as by the co-medications ciprofloxacin, levetiracetam, and propranolol. In order to prescribe an optimal drug dosage, pre-emptive pharmacogenetic testing and careful consideration of co-medications in addition to therapeutic drug monitoring might improve voriconazole treatment outcome of children with invasive fungal infections.

Effects of CYP2C19, CYP2C9 and CYP3A4 gene polymorphisms on plasma voriconazole levels in Chinese pediatric patients

OBJECTIVES

Voriconazole is the most commonly used antifungal agent in clinical application. Previous studies suggested that voriconazole was extensively metabolized by CYP450 enzyme system, including CYP2C19, CYP2C9 and CYP3A4, which contributed to the individual variability of the pharmacokinetic process of voriconazole. This study aimed to investigate the effects of CYP2C19, CYP2C9 and CYP3A4 gene polymorphisms on plasma voriconazole concentrations in Chinese pediatric patients.

METHODS

This study prospectively evaluated pediatric patients administrating voriconazole for the treatment or prophylaxis of invasive fungal infections from October 2018 to July 2020. Seven single-nucleotide polymorphisms in CYP2C19 (CYP2C19*2, CYP2C19*3, and CYP2C19*17), CYP2C9 (CYP2C9*3, CYP2C9*13) and CYP3A4 (CYP3A4*22, rs4646437) were detected by real-time fluorescent PCR with TaqMan probes. The voriconazole trough plasma concentration was determined by UPLC-MS/MS.

RESULTS

A total of 68 pediatric patients were enrolled in this study. Our results showed that voriconazole plasma concentrations of patients with CYP2C19*2 or CYP2C19*3 allele were significantly higher than that with wild-type carriers (P < 0.0001, P = 0.004, respectively). However, CYP2C9*3 and CYP3A4 rs4646437 were not significantly associated with voriconazole plasma levels. The CYP2C19*17, CYP2C9*13 and CYP3A4*22 alleles were not observed in our study. Additionally, multiple linear regression analysis indicated that CYP2C19*2 and CYP2C19*3 alleles remained predictors of voriconazole plasma concentration (r2 = 0.428; P < 0.0001). For CYP2C19 metabolizer phenotype, trough concentration of voriconazole was significantly lower in NM group compared with IM (P < 0.0001) and PM (P = 0.004) groups.

CONCLUSION

Voriconazole plasma levels in pediatric patients are mainly affected by CYP2C19 gene polymorphisms.

Rapid detection of FMO3 single nucleotide polymorphisms using a pyrosequencing method

The present study aimed to develop a reliable pyrosequencing method to detect four single nucleotide polymorphisms (SNPs) of the flavin‑containing monooxygenase 3 (FMO3) gene and to compare the ethnic differences in their allelic frequencies. The pyrosequencing method was used to detect four FMO3 SNPs, namely, c.855C>T (N285N, rs909530), c.441C>T (S147S, rs1800822), c.923A>G (E308G, rs2266780) and c.472G>A (E158K, rs2266782). The allelic frequencies of these SNPs in 122 unrelated Korean subjects were as follows: i) 44.7% for c.855C>T; ii) 23.4% for c.441C>T; iii) 23.0% for c.923A>G; and iv) 27.1% for c.472G>A. Linkage disequilibrium (LD) analysis revealed that the SNPs c.923A>G and c.472G>A exhibited a strong LD (D'=0.8289, r²=0.5332). In conclusion, the pyrosequencing method developed in this study was successfully applied to detect the c.855C>T, c.441C>T, c.923A>G and c.472G>A SNPs of FMO3.

CYP2C19 Phenotype and Body Weight-Guided Voriconazole Initial Dose in Infants and Children after Hematopoietic Cell Transplantation

Prophylactic voriconazole use is recommended for children undergoing hematopoietic cell transplantation (HCT). Dosing considerations are essential, due to the narrow therapeutic window of voriconazole. Known covariates do not sufficiently explain the large interindividual pharmacokinetic (PK) variability of voriconazole. Moreover, knowledge of voriconazole PK for age <2 years is limited. We investigated genetic and clinical covariate associations with voriconazole interindividual PK variability and subsequently simulated dosing regimens in children. This study was conducted as part of a single-institution, phase I study of intravenous voriconazole therapy for children undergoing HCT. We conducted a population PK analysis and tested covariate effects on voriconazole PK, including 67 genetic variants and clinical variables. We analyzed plasma voriconazole and N-oxide metabolite concentrations from 58 children <21 years of age (including 12 children <2 years of age). A two-compartment parent mixed linear/nonlinear model best described our data. The CYP2C19 phenotype and body weight were significant covariates (P < 0.05 for both). Our model performance for age <2 years was comparable to that for other age groups. Simulation of the final model suggested the following doses to attain target steady-state trough concentrations of 1.5 to 5.0 mg/liter for the CYP2C19 normal phenotype: 16 mg/kg (weight of <15 kg), 12 mg/kg (weight of 15 to 30 kg), or 10 mg/kg (weight of >30 kg); doses were 33 to 50% lower for CYP2C19 poor/intermediate phenotypes and 25 to 50% higher for CYP2C19 rapid/ultrarapid phenotypes. We propose a new starting-dose regimen, combined with therapeutic drug monitoring, for intravenous voriconazole therapy in children of all ages. Future studies should validate this dosing regimen.

Pharmacogenomics research and its clinical implementation in Thailand: Lessons learned from the resource-limited settings

Several barriers present challenges to implementing pharmacogenomics into practice. This review will provide an overview of the current pharmacogenomics practices and research in Thailand, address the challenges and lessons learned from delivering clinical pharmacogenomic services in Thailand, emphasize the pharmacogenomics implementation issues that must be overcome, and identify current pharmacogenomic initiatives and plans to facilitate clinical implementation of pharmacogenomics in Thailand. Ever since the pharmacogenomics research began in 2004 in Thailand, a multitude of pharmacogenomics variants associated with drug responses have been identified in the Thai population, such as HLA-B∗15:02 for carbamazepine and oxcarbazepine, HLA-B∗58:01 for allopurinol, HLA-B∗13:01 for dapsone and cotrimoxazole, CYP2B6 variants for efavirenz, CYP2C9∗3 for phenytoin and warfarin, CYP3A5∗3 for tacrolimus, and UGT1A1∗6 and UGT1A1∗28 for irinotecan, etc. The future of pharmacogenomics guided therapy in clinical settings across Thailand appears promising because of the availability of evidence of clinical validity of the pharmacogenomics testing and support for reimbursement of pharmacogenomics testing.