Population pharmacokinetics of voriconazole and initial dosage optimization in patients with talaromycosis

Voriconazole Steady-State Trough Concentrations and Clinical Outcomes in Patients with Talaromycosis

BACKGROUND

Voriconazole (VRC) has been used as an alternative treatment for talaromycosis. However, there are few studies reporting the VRC plasma concentration in patients with talaromycosis. The purpose of this study was to analyze the correlations between VRC initial steady-state trough concentration and clinical outcomes.

METHODS

We prospectively enrolled patients who were diagnosed with talaromycosis and received VRC as initial antifungal treatment regime. Medical information, VRC initial steady-state trough concentration, clinical outcomes and adverse events (AEs) were recorded for analysis.

RESULTS

This study included 69 patients with talaromycosis receiving VRC treatment, including 38 HIV-positive patients and 31 HIV-negative patients. The average age of the HIV-positive patients was 42 years, and that of the HIV-negative patients was 51 years. After 12 weeks of antifungal treatment, 55 patients achieved clinical remission, 3 patients were transferred to amphotericin B treatment because of persistent clinical symptoms, and 5 patients died, 2 patients discontinued VRC treatment due to AEs. Follow up to 6 months, a total of 14 AEs were observed in 12 patients, and 3 patients discontinued VRC treatment due to AEs. The average VRC initial steady-state trough concentration was 5.26 mg/L, with a range of 0.23-16.95 mg/L, indicating high variability. No correlation was found between the VRC initial steady-state trough concentration and treatment failure (P = 0.079). A significant correlation between AEs and the VRC initial steady-state trough concentration was found (P = 0.048). The VRC initial steady-state trough concentration threshold for AEs was 5.88 mg/L according to the ROC curve analysis. In addition, there was a significant correlation between mortality and the APACHE II score (P = 0.029). The risk of death significantly increased when the APACHE II score was > 10.

CONCLUSION

Voriconazole is an effective antifungal drug for talaromycosis in patients with APACHE II scores < 10. VRC steady-state trough concentration may not be significantly correlated with poor prognosis. A high VRC trough concentration was significantly correlated with AEs, and it may promote the management of AEs.

Voriconazole: a review of adjustment programs guided by therapeutic drug monitoring

Objectives

Exploring adjustments to the voriconazole dosing program based on therapeutic drug monitoring results to implement individualized therapy.

Methods

PubMed and Embase were systematically searched to obtain study about voriconazole dose adjustment program guided by therapeutic drug monitoring. Quality evaluation and summarization of the obtained studies were performed to obtain program adjustments for voriconazole under therapeutic drug monitoring.

Results

A total of 1,356 and 2,979 studies were searched on PubMed and Embase, respectively, and after removing irrelevant and duplicated studies, a total of 25 studies were included. A loading dose of 5 mg/kg q12 h or 200 mg q12 h and a maintenance dose of 50 mg q12 h or 100 mg q24 h is recommended for patients with Child-Pugh C. And in patients with Child-Pugh C, CYP2C19 genotype had no significant effect on voriconazole blood concentrations. Recommendations for presenting dosing programs based on different CYP2C19 genotypes are inconsistent, and genetic testing is not routinely recommended prior to dosing from a pharmacoeconomic perspective. Additionally, in adult patients, if the voriconazole trough concentration is subtherapeutic, the voriconazole dose should be increased by 25%∼50%. If the voriconazole trough concentration is supratherapeutic,the voriconazole dose should be decreased by 25%∼50%. If a drug-related adverse event occurs, hold 1 dose, decrease subsequent dose by 50%.In pediatric patients, if the voriconazole trough concentration is subtherapeutic, increase the voriconazole dose by 1∼2 mg/kg or increase the voriconazole dose by 50%. If the voriconazole trough concentration is supratherapeutic, reduce the voriconazole dose by 1 mg/kg or hold 1 dose, and decrease the subsequent dose by 25%.

Conclusion

It is recommended that all patients on voriconazole should have their initial dosing program selected on the basis of their hepatic function or other influencing factors (e.g., pathogens, infections, C-reactive protein, albumin, or obesity), and that therapeutic concentrations should be achieved through appropriate dosage adjustments guided by therapeutic drug monitoring. Routine genetic testing for voriconazole application in patients is not considered necessary at this time. However, there has been a great deal of research and partial consensus on individualized dosing of voriconazole, but there are still some critical issues that have not been resolved.

Influence of C-reactive protein on the pharmacokinetics of voriconazole in relation to the CYP2C19 genotype: a population pharmacokinetics analysis

Voriconazole is a broad-spectrum triazole antifungal agent. A number of studies have revealed that the impact of C-reactive protein (CRP) on voriconazole pharmacokinetics was associated with the CYP2C19 phenotype. However, the combined effects of CYP2C19 genetic polymorphisms and inflammation on voriconazole pharmacokinetics have not been considered in previous population pharmacokinetic (PPK) studies, especially in the Chinese population. This study aimed to analyze the impact of inflammation on the pharmacokinetics of voriconazole in patients with different CYP2C19 genotypes and optimize the dosage of administration. Data were obtained retrospectively from adult patients aged ≥16 years who received voriconazole for invasive fungal infections from October 2020 to June 2023. Plasma voriconazole levels were measured via high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). CYP2C19 genotyping was performed using the fluorescence in situ hybridization method. A PPK model was developed using the nonlinear mixed-effect model (NONMEM). The final model was validated using bootstrap, visual predictive check (VPC), and normalized prediction distribution error (NPDE). The Monte Carlo simulation was applied to evaluate and optimize the dosing regimens. A total of 232 voriconazole steady-state trough concentrations from 167 patients were included. A one-compartment model with first order and elimination adequately described the data. The typical clearance (CL) and the volume of distribution (V) of voriconazole were 3.83 L/h and 134 L, respectively. The bioavailability was 96.5%. Covariate analysis indicated that the CL of voriconazole was substantially influenced by age, albumin, gender, CRP, and CYP2C19 genetic variations. The V of voriconazole was significantly associated with body weight. An increase in the CRP concentration significantly decreased voriconazole CL in patients with the CYP2C19 normal metabolizer (NM) and intermediate metabolizer (IM), but it had no significant effect on patients with the CYP2C19 poor metabolizer (PM). The Monte Carlo simulation based on CRP levels indicated that patients with high CRP concentrations required a decreased dose to attain the therapeutic trough concentration and avoid adverse drug reactions in NM and IM patients. These results indicate that CRP affects the pharmacokinetics of voriconazole and is associated with the CYP2C19 phenotype. Clinicians dosing voriconazole should consider the patient's CRP level, especially in CYP2C19 NMs and IMs.

Development and validation of a clinical risk score nomogram for predicting voriconazole trough concentration above 5 mg/L: a retrospective cohort study

The therapeutic range of voriconazole (VRC) is narrow, this study aimed to explore factors influencing VRC plasma concentrations > 5 mg/L and to construct a clinical risk score nomogram prediction model. Clinical data from 221 patients with VRC prophylaxis and treatment were retrospectively analyzed. The patients were randomly divided into a training cohort and a validation cohort at a 7:3 ratio. Univariate and binary logistic regression analysis was used to select independent risk factors for VRC plasma concentration above the high limit (5 mg/L). Four indicators including age, weight, CYP2C19 genotype, and albumin were selected to construct the nomogram prediction model. The area under the curve values of the training cohort and the validation cohort were 0.841 and 0.802, respectively. The decision curve analysis suggests that the nomogram model had good clinical applicability. In conclusion, the nomogram provides a reference for early screening and intervention in a high-risk population.

Renal Replacement Therapy as a New Indicator of Voriconazole Clearance in a Population Pharmacokinetic Analysis of Critically Ill Patients

AIMS

The pharmacokinetic (PK) profiles of voriconazole in intensive care unit (ICU) patients differ from that in other patients. We aimed to develop a population pharmacokinetic (PopPK) model to evaluate the effects of using extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT) and those of various biological covariates on the voriconazole PK profile.

METHODS

Modeling analyses of the PK parameters were conducted using the nonlinear mixed-effects modeling method (NONMEM) with a two-compartment model. Monte Carlo simulations (MCSs) were performed to observe the probability of target attainment (PTA) when receiving CRRT or not under different dosage regimens, different stratifications of quick C-reactive protein (qCRP), and different minimum inhibitory concentration (MIC) ranges.

RESULTS

A total of 408 critically ill patients with 746 voriconazole concentration-time data points were included in this study. A two-compartment population PK model with qCRP, CRRT, creatinine clearance rate (CLCR), platelets (PLT), and prothrombin time (PT) as fixed effects was developed using the NONMEM.

CONCLUSIONS

We found that qCRP, CRRT, CLCR, PLT, and PT affected the voriconazole clearance. The most commonly used clinical regimen of 200 mg q12h was sufficient for the most common sensitive pathogens (MIC ≤ 0.25 mg/L), regardless of whether CRRT was performed and the level of qCRP. When the MIC was 0.5 mg/L, 200 mg q12h was insufficient only when the qCRP was <40 mg/L and CRRT was performed. When the MIC was ≥2 mg/L, a dose of 300 mg q12h could not achieve ≥ 90% PTA, necessitating the evaluation of a higher dose.

Enhancing voriconazole therapy in liver dysfunction: exploring administration schemes and predictive factors for trough concentration and efficacy

Introduction: The application of voriconazole in patients with liver dysfunction lacks pharmacokinetic data. In previous study, we proposed to develop voriconazole dosing regimens for these patients according to their total bilirubin, but the regimens are based on Monte Carlo simulation and has not been further verified in clinical practice. Besides, there are few reported factors that significantly affect the efficacy of voriconazole. Methods: We collected the information of patients with liver dysfunction hospitalized in our hospital from January 2018 to May 2022 retrospectively, including their baseline information and laboratory data. We mainly evaluated the efficacy of voriconazole and the target attainment of voriconazole trough concentration. Results: A total of 157 patients with liver dysfunction were included, from whom 145 initial and 139 final voriconazole trough concentrations were measured. 60.5% (95/157) of patients experienced the adjustment of dose or frequency. The initial voriconazole trough concentrations were significantly higher than the final (mean, 4.47 versus 3.90 μg/mL, p = 0.0297). Furthermore, daily dose, direct bilirubin, lymphocyte counts and percentage, platelet, blood urea nitrogen and creatinine seven covariates were identified as the factors significantly affect the voriconazole trough concentration. Binary logistic regression analysis revealed that the lymphocyte percentage significantly affected the efficacy of voriconazole (OR 1.138, 95% CI 1.016-1.273), which was further validated by the receiver operating characteristic curve. Conclusion: The significant variation in voriconazole trough concentrations observed in patients with liver dysfunction necessitates caution when prescribing this drug. Clinicians should consider the identified factors, particularly lymphocyte percentage, when dosing voriconazole in this population.

Can we predict the influence of inflammation on voriconazole exposure? An overview

Voriconazole is a triazole antifungal indicated for invasive fungal infections that exhibits a high degree of inter-individual and intra-individual pharmacokinetic variability. Voriconazole pharmacokinetics is non-linear, making dosage adjustments more difficult. Therapeutic drug monitoring is recommended by measurement of minimum plasma concentrations. Several factors are responsible for the high pharmacokinetic variability of voriconazole: age, feeding (which decreases absorption), liver function, genetic polymorphism of the CYP2C19 gene, drug interactions and inflammation. Invasive fungal infections are indeed very frequently associated with inflammation, which engenders a risk of voriconazole overexposure. Many studies have reviewed this topic in both the adult and paediatric populations, but few studies have focused on the specific point of the prediction, to evaluate the influence of inflammation on voriconazole pharmacokinetics. Predicting the impact of inflammation on voriconazole pharmacokinetics could help optimize antifungal therapy and improve patient management. This review summarizes the existing data on the influence of inflammation on voriconazole pharmacokinetics in adult populations. We also evaluate the role of C-reactive protein, the impact of inflammation on patient metabolic phenotypes, and the tools that can be used to predict the effect of inflammation on voriconazole pharmacokinetics.

Voriconazole exposure is influenced by inflammation: A population pharmacokinetic model

BACKGROUND

Voriconazole is an antifungal drug used for the treatment of invasive fungal infections. Due to highly variable drug exposure, therapeutic drug monitoring (TDM) has been recommended. TDM may be helpful to predict exposure accurately, but covariates, such as severe inflammation, that influence the metabolism of voriconazole have not been included in the population pharmacokinetic (popPK) models suitable for routine TDM.

OBJECTIVES

To investigate whether the effect of inflammation, reflected by C-reactive protein (CRP), could improve a popPK model that can be applied in clinical care.

PATIENTS AND METHODS

Data from two previous studies were included in the popPK modelling. PopPK modelling was performed using Edsim++. Different popPK models were compared using Akaike Information Criterion and goodness-of-fit plots.

RESULTS

In total, 1060 voriconazole serum concentrations from 54 patients were included in this study. The final model was a one-compartment model with non-linear elimination. Only CRP was a significant covariate, and was included in the final model and found to affect the maximum rate of enzyme activity (V_max). For the final popPK model, the mean volume of distribution was 145 L [coefficient of variation percentage (CV%)=61%], mean Michaelis-Menten constant was 5.7 mg/L (CV%=119%), mean V_max was 86.4 mg/h (CV%=99%) and mean bioavailability was 0.83 (CV%=143%). Internal validation using bootstrapping resulted in median values close to the population parameter estimates.

CONCLUSIONS

This one-compartment model with non-linear elimination and CRP as a covariate described the pharmacokinetics of voriconazole adequately.