Correlation of CYP2C19 genotype with plasma voriconazole exposure in South-western Chinese Han patients with invasive fungal infections

Associated factors with voriconazole plasma concentration: a systematic review and meta-analysis

Background: Voriconazole plasma concentration exhibits significant variability and maintaining it within the therapeutic range is the key to enhancing its efficacy. We conducted a systematic review and meta-analysis to estimate the prevalence of patients achieving the therapeutic range of plasma voriconazole concentration and identify associated factors. Methods: Eligible studies were identified through the PubMed, Embase, Cochrane Library, and Web of Science databases from their inception until 18 November 2023. We conducted a meta-analysis using a random-effects model to determine the prevalence of patients who reached the therapeutic plasma voriconazole concentration range. Factors associated with plasma voriconazole concentration were summarized from the included studies. Results: Of the 60 eligible studies, 52 reported the prevalence of patients reaching the therapeutic range, while 20 performed multiple linear regression analyses. The pooled prevalence who achieved the therapeutic range was 56% (95% CI: 50%-63%) in studies without dose adjustment patients. The pooled prevalence of adult patients was 61% (95% CI: 56%-65%), and the pooled prevalence of children patients was 55% (95% CI: 50%-60%) The study identified, in the children population, several factors associated with plasma voriconazole concentration, including age (coefficient 0.08, 95% CI: 0.01 to 0.14), albumin (-0.05 95% CI: -0.09 to -0.01), in the adult population, some factors related to voriconazole plasma concentration, including omeprazole (1.37, 95% CI 0.82 to 1.92), pantoprazole (1.11, 95% CI: 0.17-2.04), methylprednisolone (-1.75, 95% CI: -2.21 to -1.30), and dexamethasone (-1.45, 95% CI: -2.07 to -0.83). Conclusion: The analysis revealed that only approximately half of the patients reached the plasma voriconazole concentration therapeutic range without dose adjustments and the pooled prevalence of adult patients reaching the therapeutic range is higher than that of children. Therapeutic drug monitoring is crucial in the administration of voriconazole, especially in the children population. Particular attention may be paid to age, albumin levels in children, and the use of omeprazole, pantoprazole, dexamethasone and methylprednisolone in adults. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023483728.

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.

Establishment of a mathematical prediction model for voriconazole stable maintenance dose: a prospective study

Background

In patients with invasive fungal infection (IFI), the steady-state serum trough concentration (C min) of voriconazole (VCZ) is highly variable and can lead to treatment failure (C min < 0.5 mg/L) and toxicity (C min ≥ 5.0 mg/L). However, It remains challenging to determine the ideal maintenance dose to achieve the desired C min level quickly.

Aims

This randomized, prospective observational single-center study aimed to identify factors affecting VCZ-C min and maintenance dose and create an algorithmic model to predict the necessary maintenance dose. MeThe study enrolled 306 adult IFI patients, split into two groups: non-gene-directed (A) (where CYP2C19 phenotype is not involved in determining VCZ dose) and gene-directed (B) (where CYP2C19 phenotype is involved in determining VCZ dose).

Results

Results indicated that CYP2C19 genetic polymorphisms might significantly impact VCZ loading and maintenance dose selection. CYP2C19 phenotype, C-reaction protein (CRP), and average daily dose/body weight were significant influencers on VCZ-C min, while CYP2C19 phenotype, CRP, and body weight significantly impacted VCZ maintenance dose. A feasible predictive formula for VCZ stable maintenance dose was derived from the regression equation as a maintenance dose (mg) =282.774-0.735×age (year)+2.946×body weight(Kg)-19.402×CYP2C19 phenotype (UM/RM/NM:0, IM:1, PM:2)-0.316×CRP (mg/L) (p < 0.001).

Discussion

DiThis formula may serve as a valuable supplement to the Clinical Pharmacogenetics Implementation Consortium (CPIC®) guideline for CYP2C19 and VCZ therapy, especially for IFI patients with highly variable inflammatory cytokines during VCZ therapy.

A survey to describe common practices on antifungal monitoring among Spanish clinicians

INTRODUCTION

We developed a survey to obtain information on the monitoring practices of major systemic antifungals for treatment and prevention of serious fungal infection.

METHODS

The survey included questions relating to methodology and practice and was distributed among 137 colleagues of the Study Group of Medical Mycology (GEMICOMED) from July to December 2019.

RESULTS

Monitoring was routinely carried out by most respondents, mainly for voriconazole, and was more likely used to determine the efficacy of the dose administered and less for minimizing drug toxicity. Most responders did not follow the strategies of voriconazole dosage based on CYP2C19 genotyping. Monitoring of posaconazole, itraconazole, or other azole metabolites was not carried out or scarcely demanded. Most responders rarely used flucytosine in their clinical practice nor did they monitor it. According to the answers given by some responders, monitoring isavuconazole, amphotericin B, caspofungin and fluconazole exposure would be also interesting in daily clinical practice in selected patient populations.

CONCLUSIONS

The survey reveals common practices and attitudes towards antifungal monitoring, sometimes not performed as per best recommendations, offering an opportunity for education and research. Appropriate use of therapeutic drug monitoring may be an objective of antifungal stewardship programmes.

Challenges in the Treatment of Invasive Aspergillosis in Immunocompromised Children

Invasive aspergillosis (IA) is associated with significant morbidity and mortality. Voriconazole remains the drug of choice for the treatment of IA in children; however, the complex kinetics of voriconazole in children make dosing challenging and therapeutic drug monitoring (TDM) essential for treatment success. The overarching goal of this review is to discuss the role of voriconazole, posaconazole, isavuconazole, liposomal amphotericin B, echinocandins, and combination antifungal therapy for the treatment of IA in children. We also provide a detailed discussion of antifungal TDM in children.

Antifungal Drugs TDM: Trends and Update

PURPOSE

The increasing burden of invasive fungal infections results in growing challenges to antifungal (AF) therapeutic drug monitoring (TDM). This review aims to provide an overview of recent advances in AF TDM.

METHODS

We conducted a PubMed search for articles during 2016-2020 using "TDM" or "pharmacokinetics" or "drug-drug-interaction" with "antifungal," consolidated for each AF. Selection was limited to English language articles with human data on drug exposure.

RESULTS

More than 1000 articles matched the search terms. We selected 566 publications. The latest findings tend to confirm previous observations in real-life clinical settings. The pharmacokinetic variability related to special populations is not specific but must be considered. AF benefit-to-risk ratio, drug-drug interaction (DDI) profiles, and minimal inhibitory concentrations for pathogens must be known to manage at-risk situations and patients. Itraconazole has replaced ketoconazole in healthy volunteers DDI studies. Physiologically based pharmacokinetic modeling is widely used to assess metabolic azole DDI. AF prophylactic use was studied more for Aspergillus spp. and Mucorales in oncohematology and solid organ transplantation than for Candida (already studied). Emergence of central nervous system infection and severe infections in immunocompetent individuals both merit special attention. TDM is more challenging for azoles than amphotericin B and echinocandins. Fewer TDM requirements exist for fluconazole and isavuconazole (ISZ); however, ISZ is frequently used in clinical situations in which TDM is recommended. Voriconazole remains the most challenging of the AF, with toxicity limiting high-dose treatments. Moreover, alternative treatments (posaconazole tablets, ISZ) are now available.

CONCLUSIONS

TDM seems to be crucial for curative and/or long-term maintenance treatment in highly variable patients. TDM poses fewer cost issues than the drugs themselves or subsequent treatment issues. The integration of clinical pharmacology into multidisciplinary management is now increasingly seen as a part of patient care.

A survey to describe common practices on antifungal monitoring among Spanish clinicians

INTRODUCTION

We developed a survey to obtain information on the monitoring practices of major systemic antifungals for treatment and prevention of serious fungal infection.

METHODS

The survey included questions relating to methodology and practice and was distributed among 137 colleagues of the Study Group of Medical Mycology (GEMICOMED) from July to December 2019.

RESULTS

Monitoring was routinely carried out by most respondents, mainly for voriconazole, and was more likely used to determine the efficacy of the dose administered and less for minimizing drug toxicity. Most responders did not follow the strategies of voriconazole dosage based on CYP2C19 genotyping. Monitoring of posaconazole, itraconazole, or other azole metabolites was not carried out or scarcely demanded. Most responders rarely used flucytosine in their clinical practice nor did they monitor it. According to the answers given by some responders, monitoring isavuconazole, amphotericin B, caspofungin and fluconazole exposure would be also interesting in daily clinical practice in selected patient populations.

CONCLUSIONS

The survey reveals common practices and attitudes towards antifungal monitoring, sometimes not performed as per best recommendations, offering an opportunity for education and research. Appropriate use of therapeutic drug monitoring may be an objective of antifungal stewardship programmes.

The influence of CYP2C19 polymorphisms on voriconazole trough concentrations: Systematic review and meta-analysis

BACKGROUND

Voriconazole primary metabolism is catalysed by CYP2C19. A large variability of trough concentrations in patients with invasive fungal infection treated with voriconazole has been observed in clinical practice. It remains controversial whether the CYP2C19 polymorphisms are responsible for voriconazole metabolism in the individual variation.

OBJECTIVES

The primary aim of this study was to assess the effect of CYP2C19 polymorphisms on voriconazole trough concentrations.

METHODS

Following a systematic literature review, we performed a meta-analysis for mean differences (MD) of voriconazole trough concentrations (C_min ), voriconazole dosage adjusted trough concentrations (C_min /D) and for risk ratio (RR) of the proportion of patients in the target therapeutic range between pairwise comparisons of CYP2C19 phenotypes.

RESULTS

Compared with normal metabolisers (NMs), intermediate metabolisers (IMs) (MD: 0.82, 95% CI: 0.57 to 1.07, I²  = 44%, p < .00001) or poor metabolisers (PMs) (MD: 1.59, 95% CI: 1.14 to 2.05, I²  = 46%, p < .00001) had significantly higher voriconazole C_min (μg·ml^-1 ), while rapid metabolisers (RMs) had significantly lower voriconazole C_min (MD: -0,87, 95% CI: -1.35 to -0.38, I²  = 0%, p = .0004). In addition, IMs had significantly lower C_min than PMs (MD: -0.59, 95% CI: -0.97 to -0.20, I²  = 22%, p = .003). Similarly, the C_min /D (μg·kg·ml^-1 ·mg^-1 ) was significantly higher in IMs (MD: 0.13, 95% CI: 0.05 to 0.22, I²  = 0%, p = .002) and PMs (MD: 0.20, 95% CI: 0.07 to 0.34, I²  = 0%, p = .003) than that in NMs, and also, IMs had significantly lower C_min /D than PMs (MD: -0.11, 95% CI: -0.14 to -0.08, I²  = 0%, p < .00001). Furthermore, PMs had a significantly higher proportion of the target therapeutic range than NMs (RR: 1.34, 95% CI: 1.09 to 1.64, I²  = 50%, p = .005).

CONCLUSIONS

Compared to NMs, IMs and PMs had higher voriconazole trough concentrations, especially in Asians, while RMs had lower voriconazole trough concentrations. In addition, PMs had a higher proportion of the target therapeutic range than NMs, especially in Asians. CYP2C19 genotyping is expected to be used to preemptively guide the individualisation of voriconazole in clinical practice.

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

Voriconazole is the first-line antifungal choice in the treatment of invasive fungal infections (IFIs). Single nucleotide polymorphisms (SNPs) in drug-metabolizing and transporter genes may affect voriconazole pharmacokinetics. This study aimed to determine the frequency of the CYP2C19 rs4244285, rs4986893, rs72552267, and rs12248560, CYP3A4 rs4646437, ABCB1 rs1045642, and FMO3 rs2266782 alleles and determine the association between these genetic variants and voriconazole concentrations in Thai patients with invasive fungal infections. The study comprised 177 Thai patients with IFIs in whom seven SNPs in CYP2C19, CYP3A4, ABCB1, and FMO3 were genotyped using TaqMan real-time polymerase chain reaction (RT-PCR) 5´ nuclease assays, and voriconazole plasma concentrations were measured by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Of the 177 patients included, 31 were <12 years and 146 were ≥12 years. The CYP2C19 allele frequencies were 0.29 for *2, 0.060 for *3, 0.003 for *6, and 0.008 for *17. The allele frequency of CYP3A4 (rs4646437) was 0.26, ABCB1 (rs1045642) was 0.36, and FMO3 (rs2266782) was 0.16. The median voriconazole dose/weight was significantly lower in patients aged ≥12 years when compared to the patients aged <12 years (P < .001). Patients aged <12 years with CYP2C19*1/*2 exhibited significantly higher median voriconazole plasma concentrations than those with the CYP2C19*1/*1 (P = .038). However, there were no significant differences in median voriconazole plasma concentrations among the CYP2C19 genotypes in the patients aged ≥12 years. There was a lack of association observed among the CYP3A4, ABCB1, and FMO3 genotypes on the plasma voriconazole concentrations in both groups of patients. Our findings indicate that voriconazole plasma concentrations are affected by the CYP2C19*2 allele in patients aged <12 years but not in patients aged ≥12 years.

Predictors of Adverse Events and Determinants of the Voriconazole Trough Concentration in Kidney Transplantation Recipients

Voriconazole is the mainstay for the treatment of invasive fungal infections in patients who underwent a kidney transplant. Variant CYP2C19 alleles, hepatic function, and concomitant medications are directly involved in the metabolism of voriconazole. However, the drug is also associated with numerous adverse events. The purpose of this study was to identify predictors of adverse events using binary logistic regression and to measure its trough concentration using multiple linear modeling. We conducted a prospective analysis of 93 kidney recipients cotreated with voriconazole and recorded 213 trough concentrations of it. Predictors of the adverse events were voriconazole trough concentration with the odds ratios (OR) of 2.614 (P = 0.016), cytochrome P450 2C19 (CYP2C19), and hemoglobin (OR 0.181, P = 0.005). The predictive power of these three factors was 91.30%. We also found that CYP2C19 phenotypes, hemoglobin, platelet count, and concomitant use of ilaprazole had quantitative relationships with voriconazole trough concentration. The fit coefficient of this regression equation was R²  = 0.336, demonstrating that the model explained 33.60% of interindividual variability in the disposition of voriconazole. In conclusion, predictors of adverse events are CYP2C19 phenotypes, hemoglobin, and voriconazole trough concentration. Determinants of the voriconazole trough concentration were CYP2C19 phenotypes, platelet count, hemoglobin, concomitant use of ilaprazole. If we consider these factors during voriconazole use, we are likely to maximize the treatment effect and minimize adverse events.

Effect of CYP2C19 polymorphism on the plasma voriconazole concentration and voriconazole-to-voriconazole-N-oxide concentration ratio in elderly patients

BACKGROUND

Effects of CYP2C19 polymorphism on voriconazole concentration (C0 ), dose-adjusted trough concentrations (C0 /dose) and voriconazole-to-voriconazole-N-oxide concentration ratio (C0 /CN ) have not been fully investigated.

OBJECTIVES

To investigate correlations of CYP2C19 polymorphisms with plasma concentrations of voriconazole and the major metabolite voriconazole-N-oxide in elderly patients.

METHODS

A prospective, multi-centre, non-intervention, open clinical study was conducted within Southwestern Chinese patients clinically diagnosed with invasive fungal infections, to investigate the associations of CYP2C19∗2 (681G > A), CYP2C19∗3 (636G > A) and CYP2C19∗17 (-806C > T) genetic polymorphisms with voriconazole C0 , C0 /dose and C0 /CN .

RESULTS

The study included 131 adult patients, of which 72 were elderly (≥60 years) and 59 were adults (<60 years). The allele frequencies of CYP2C19∗2, ∗3 and ∗17 in the elderly cohort were 61.1%, 29.9% and 7.6%, respectively, which were similar to those in the adult cohort (66.9%, 29.7% and 2.5%, respectively; P > .05). The median voriconazole C0 (C0 ), C0 /dose and C0 /CN ratio in patients with the CYP2C19∗1/∗2 and CYP2C19∗2/∗2 genotypes were significantly higher than those in patients with the CYP2C19∗1/∗1 genotype in the adult cohort (P < .05). The C0 and C0 /dose in patients with the CYP2C19∗1/∗3 and CYP2C19∗2/∗2 genotypes, and the C0 /CN ratio for patients with the CYP2C19∗1/∗2 genotype were numerically higher than those in patients with the CYP2C19∗1/∗1 genotype in the elderly cohort, but this difference was not statistically significant (P > 0.05). The C0 , C0 /dose and C0 /CN in patients with poor metaboliser phenotypes were higher than in those with normal metaboliser phenotypes and C0 in patients with intermediate metaboliser phenotypes were significantly higher than in those with normal metaboliser phenotypes in the adult cohort (P < .05). However, there were no significant differences in the C0 , C0 /dose and C0 /CN among different CYP2C19-predicted metabolic phenotypes in the elderly cohort.

CONCLUSIONS

Voriconazole C0 , C0 /dose and C0 /CN ratio are not significantly affected by the CYP2C19∗2/∗3 polymorphisms in the elderly patients.

Pharmacokinetics of intravenous voriconazole in patients with liver dysfunction: A prospective study in the intensive care unit

OBJECTIVES

To characterize the pharmacokinetics (PK) of intravenous voriconazole (VRC) in critically ill patients with liver dysfunction.

METHODS

Patients with liver dysfunction in the intensive care unit (ICU) were included prospectively. The Child-Pugh score was used to categorize the degree of liver dysfunction. The initial intravenous VRC dosing regimen comprised a loading dose of 300 mg every 12 h for the first 24 h, followed by 200 mg every 12 h. The first PK curves (PK curve 1) were drawn within one dosing interval of the first dose for 17 patients; the second PK curves (PK curve 2) were drawn within one dosing interval after a minimum of seven doses for 12 patients. PK parameters were estimated by non-compartmental analysis.

RESULTS

There were good correlations between the area under the curve (AUC_0-12) of PK curve 2 and the corresponding trough concentration (C₀) and peak concentration (C_max) (r² = 0.951 and 0.963, respectively; both p < 0.001). The median half-life (t_1/2) and clearance (CL) of patients in Child-Pugh class A (n = 3), B (n = 5), and C (n = 4) of PK curve 2 were 24.4 h and 3.31 l/h, 29.1 h and 2.54 l/h, and 60.7 h and 2.04 l/h, respectively. In the different Child-Pugh classes, the CL (median) of PK curve 2 were all lower than those of PK curve 1. The apparent steady-state volume of distribution (V_ss) of PK curve 1 was positively correlated with actual body weight (r² = 0.450, p = 0.004). The median first C₀ of 17 patients determined on day 5 was 5.27 (2.61) μg/ml, and 29.4% of C₀ exceeded the upper limit of the therapeutic window (2-6 μg/ml).

CONCLUSIONS

The CL of VRC decreased with increasing severity of liver dysfunction according to the Child-Pugh classification, along with an increased t_1/2, which resulted in high plasma exposure of VRC. Adjusted dosing regimens of intravenous VRC should be established based on Child-Pugh classes for these ICU patients, and plasma concentrations should be monitored closely to avoid serious adverse events.

Applying Pharmacogenomics to Antifungal Selection and Dosing: Are We There Yet?

Purpose of Review

This review summarizes recent literature for applying pharmacogenomics to antifungal selection and dosing, providing an approach to implementing antifungal pharmacogenomics in clinical practice.

Recent Findings

The Clinical Pharmacogenetics Implementation Consortium published guidelines on CYP2C19 and voriconazole, with recommendations to use alternative antifungals or adjust voriconazole dose with close therapeutic drug monitoring (TDM). Recent studies demonstrate an association between CYP2C19 phenotype and voriconazole levels, clinical outcomes, and adverse events. Additionally, CYP2C19-guided preemptive dose adjustment demonstrated benefit in two prospective studies for prophylaxis. Pharmacokinetic-pharmacodynamic modeling studies have generated proposed voriconazole treatment doses based on CYP2C19 phenotypes, with further validation studies needed.

Summary

Sufficient evidence is available for implementing CYP2C19-guided voriconazole selection and dosing among select patients at risk for invasive fungal infections. The institution needs appropriate infrastructure for pharmacogenomic testing, integration of results in the clinical decision process, with TDM confirmation of goal trough achievement, to integrate antifungal pharmacogenomics into routine clinical care.