Practice guidelines for therapeutic drug monitoring of voriconazole: a consensus review of the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring

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.

Clinical application of voriconazole in pediatric patients: a systematic review

The purpose of this study was to review the literature on the clinical use of voriconazole (VRC) in pediatric patients. MEDLINE, Embase, PubMed, Web of Science, and Cochrane Library were searched from January 1, 2000, to August 15, 2023 for relevant clinical studies on VRC use in pediatric patients. Data were collected based on inclusion and exclusion criteria, and a systematic review was performed on recent research related to the use of VRC in pediatric patients. This systematic review included a total of 35 observational studies among which there were 16 studies investigating factors influencing VRC plasma trough concentrations (Ctrough) in pediatric patients, 14 studies exploring VRC maintenance doses required to achieve target range of Ctrough, and 11 studies focusing on population pharmacokinetic (PPK) research of VRC in pediatric patients. Our study found that the Ctrough of VRC were influenced by both genetic and non-genetic factors. The optimal dosing of VRC was correlated with age in pediatric patients, and younger children usually required higher VRC doses to achieve target Ctrough compared to older children. Establishing a PPK model for VRC can assist in achieving more precise individualized dosing in children.

Therapeutic drug monitoring guidelines in oncology: what do we know and how to move forward? Insights from a systematic review

Background

Compared with anti-infective drugs, immunosuppressants and other fields, the application of therapeutic drug monitoring (TDM) in oncology is somewhat limited.

Objective

We aimed to provide a comprehensive understanding of TDM guidelines for antineoplastic drugs and to promote the development of individualized drug therapy in oncology.

Design

This study type is a systematic review.

Data sources and methods

This study was performed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. Databases including PubMed, Embase, the official websites of TDM-related associations and Chinese databases were comprehensively searched up to March 2023. Two investigators independently screened the literature and extracted data. The methodological and reporting quality was evaluated using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) and the Reporting Items for Practice Guidelines in Healthcare (RIGHT), respectively. Recommendations and quality evaluation results were presented by visual plots. This study was registered in PROSPERO (No. CRD42022325661).

Results

A total of eight studies were included, with publication years ranging from 2014 to 2022. From the perspective of guideline development, two guidelines were developed using evidence-based methods. Among the included guidelines, four guidelines were for cytotoxic antineoplastic drugs, three for small molecule kinase inhibitors, and one for antineoplastic biosimilars. Currently available guidelines and clinical practice provided recommendations of individualized medication in oncology based on TDM, as well as influencing factors. With regard to methodological quality based on AGREE II, the average overall quality score was 55.21%. As for the reporting quality by RIGHT evaluation, the average reporting rate was 53.57%.

Conclusion

From the perspective of current guidelines, TDM in oncology is now being expanded from cytotoxic antineoplastic drugs to newer targeted treatments. Whereas, the types of antineoplastic drugs involved are still small, and there is still room for quality improvement. Furthermore, the reflected gaps warrant future studies into the exposure-response relationships and population pharmacokinetics models.

Population Pharmacokinetics of Voriconazole and Dose Optimization in Elderly Chinese Patients

Voriconazole is commonly recommended as a first-line therapy for invasive aspergillosis infections. Elderly patients are susceptible to infectious diseases owing to their decreased physical function and immune system. Our study aims to establish a population pharmacokinetics model for elderly patients receiving intravenous voriconazole, and to optimize dosing protocols through a simulated approach. An accurate fit to the concentration-time profile of voriconazole was achieved by employing a 1-compartment model featuring first-order elimination. The typical clearance rate of voriconazole was found to be 3.22 L/h, with a typical volume of distribution of 194 L. The covariate analysis revealed that albumin (ALB), gamma-glutamyl transpeptidase, and direct bilirubin had significant impacts on voriconazole clearance. Additionally, body weight was found to be associated with the volume of distribution. Individualized dosing regimens were recommended for different ALB levels based on population pharmacokinetics model prediction. The proposed dosing regimens could provide a rationale for dosage individualization, improve the clinical outcomes, and minimize drug-related toxicities.

Optimized Antifungal Therapy for Chronic Pulmonary Aspergillosis

Chronic pulmonary aspergillosis (CPA) represents a spectrum of lung disorders caused by local proliferation of Aspergillus hyphae in individuals with non-systemic or mildly systemic immunodepression or altered pulmonary integrity due to underlying disease. While long-term systemic antifungal treatment is still the mainstay for management, surgery is considered mainly in rarer invasive disease manifestations such as sinusitis and osteomyelitis. Optimal application of existing antifungal agents with suitable pharmacokinetic properties is important for the treatment of diseases such as CPA, which requires long-term use. Appropriate management of side effects by therapeutic drug monitoring, maintenance of adherence, and assessment of drug resistance to Aspergillus can provide safe and effective treatment in the future. Most available antifungal agents for the management of mycoses in humans have disadvantages that can limit their use in clinical practice. By contrast, second generation antifungals such as triazoles have advantages of extended antifungal spectrum and availability in both oral and intravenous formulations. Isavuconazole, a new extended spectrum triazole, has been shown to be effective against Aspergillus. The safety profile and excellent pharmacokinetic characteristics of isavuconazole make it an attractive option for treatment of invasive fungal infections including CPA. With this drug now available in Japan, new evidence is expected to expand treatment options. This review focuses on the selection of antifungal agents based on national and international guidelines and the characteristics of each agent for their appropriate use in CPA.

Comparison of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and enzyme-multiplied immunoassay technique (EMIT) for quantification of voriconazole plasma concentration from Chinese patients

Introduction

Voriconazole (VRZ) is the recommended standard treatment for life-threatening invasive aspergillosis. The plasma concentration of VRZ should be determined to optimise treatment results and reduce side effects. This study aimed to compare the correlation and concordance of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and enzyme-multiplied immunoassay technique (EMIT) to determine VRZ plasma concentration in clinical practice.

Methods

An isotopically labelled internal standard UPLC-MS/MS method was established, validated, and subsequently applied to determine VRZ concentration. The UPLC-MS/MS method was also compared with a commercial EMIT method regarding results correlation and concordance.

Results

The calibration curve of UPLC-MS/MS was linear from 0.1 to 10 mg/L, the inter- and intra-day relative standard deviations (RSDs), and the stability of quality control samples were less than 15 %, satisfying the Bioanalytical Method Validation Guidelines. A total of 122 plasma samples were collected and analyzed using both methods. UPLC-MS/MS and EMIT showed a high correlation (r = 0.9534), and Bland-Altman analysis indicated a mean absolute bias of 1.035 mg/L and an average bias of 27.56 % between UPLC-MS/MS and EMIT. The paired Wilcoxon test and Bland-Altman analysis revealed poor consistency between the two methods. Furthermore, we compared the effects of different methods in clinical applications. Two threshold values for treatment efficacy (1.0 mg/L) and safety (5.5 mg/L) were established, and considerable discordance was observed between the original EMIT and UPLC-MS/MS results at both thresholds (p < 0.05). Nevertheless, the adjusted EMIT results were not inconsistent with the UPLC-MS/MS results regarding the efficacy (p = 0.125) and safety (p = 1.0) thresholds.

Conclusions

The isotopically labelled internal standard UPLC-MS/MS method is established and well applied in the clinical setting. A strong correlation but discordance was found between UPLC-MS/MS and EMIT, indicating that switching from UPLC-MS/MS to EMIT was unsuitable. However, the adjusted EMIT results may serve as a reliable surrogate when UPLC-MS/MS results cannot be obtained when necessary.

Status and Quality of Guidelines for Therapeutic Drug Monitoring Based on AGREE II Instrument

BACKGROUND

With the progress of therapeutic drug monitoring (TDM) technology and the development of evidence-based medicine, many guidelines were developed and implemented in recent decades.

OBJECTIVE

The aim was to evaluate the current status of TDM guidelines and provide suggestions for their development and updates based on Appraisal of Guidelines for Research and Evaluation (AGREE) II.

METHODS

The TDM guidelines were systematically searched for among databases including PubMed, Embase, China National Knowledge Infrastructure, Wanfang Data, and the Chinese biomedical literature service system and the official websites of TDM-related associations. The search period was from inception to 6 April 2023. Four researchers independently screened the literature and extracted data. Any disagreement was discussed and reconciled by another researcher. The quality of guidelines was assessed using the AGREE II instrument.

RESULTS

A total of 92 guidelines were included, including 57 technical guidelines, three management guidelines, and 32 comprehensive guidelines. The number of TDM guidelines has gradually increased since 1979. The United States published the most guidelines (20 guidelines), followed by China (15 guidelines) and the United Kingdom (ten guidelines), and 23 guidelines were developed by international organizations. Most guidelines are aimed at adult patients only, while 28 guidelines include special populations. With respect to formulation methods, there are 23 evidence-based guidelines. As for quality evaluation results based on AGREE II, comprehensive guidelines scored higher (58.16%) than technical guidelines (51.36%) and administrative guidelines (50.00%).

CONCLUSION

The number of TDM guidelines, especially technical and comprehensive ones, has significantly increased in recent years. Most guidelines are confronted with the problems of unclear methodology and low quality of evidence according to AGREE II. More evidence-based research on TDM and high-quality guideline development is recommended to promote individualized therapy.

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.

Positive correlation between voriconazole trough concentrations and C-reactive protein levels in patients with chronic pulmonary aspergillosis: A retrospective cohort study

BACKGROUND

Voriconazole (VRCZ) is the first-line treatment for chronic pulmonary aspergillosis (CPA). VRCZ trough concentration monitoring is recommended for adequate therapy because VRCZ concentrations vary widely. However, factors associated with variations in VRCZ concentrations, especially in the same patient at different time points, have not been identified. The objective of this study was to identify factors influencing VRCZ trough concentrations.

PATIENTS AND METHODS

This single-center retrospective study conducted at our institute between April 2014 and August 2016 included patients with CPA who received VRCZ. Patient trough concentrations were measured more than twice while the patients received the same dose using the same administration route (defined as one series). A step-wise method and multiple regression analysis were used to test the effects of patient characteristics on VRCZ trough concentrations.

RESULTS

Sixty-nine series in 49 patients were analyzed. VRCZ was administered orally in 59 series, intravenously in 7 series, and by dry syrup in 3 series. The median VRCZ trough concentration and the median variation in VRCZ concentrations were 1.68 and 0.99 μg/ml, respectively. In the simple regression analysis, creatinine, alkaline phosphatase, C-reactive protein (CRP), and creatinine clearance significantly correlated with VRCZ concentrations. Multiple regression analysis demonstrated a significant positive correlation between CRP and VRCZ concentration (P < 0.0001).

CONCLUSION

In patients with CPA, VRCZ concentration correlated with CRP levels in the same patients receiving the same dose of VRCZ at different time points.

Management of Invasive Infections in Diabetes Mellitus: A Comprehensive Review

Patients with diabetes often have more invasive infections, which may lead to an increase in morbidity. The hyperglycaemic environment promotes immune dysfunction (such as the deterioration of neutrophil activity, antioxidant system suppression, and compromised innate immunity), micro- and microangiopathies, and neuropathy. A greater number of medical interventions leads to a higher frequency of infections in diabetic patients. Diabetic individuals are susceptible to certain conditions, such as rhino-cerebral mucormycosis or aspergillosis infection. Infections may either be the primary symptom of diabetes mellitus or act as triggers in the intrinsic effects of the disease, such as diabetic ketoacidosis and hypoglycaemia, in addition to increasing morbidity. A thorough diagnosis of the severity and origin of the infection is necessary for effective treatment, which often entails surgery and extensive antibiotic use. Examining the significant issue of infection in individuals with diabetes is crucial. Comprehensive research should examine why infections are more common amongst diabetics and what the preventive treatment strategies could be.

Quantitative determination of voriconazole by thionine reduction and its potential application in a pharmaceutical and clinical setting

Voriconazole (VCZ) is a triazolic drug used to treat serious fungal infections and invasive mycosis and has also been more recently used as a generic antifungal treatment. However, VCZ therapies can cause undesirable side effects and doses must be carefully monitored before administration to avoid or reduce severe toxic effects. Analytical techniques used to quantify VCZ are mostly based on HPLC/UV and often associated with multiple technical steps as well as expensive equipment. The present work aimed to develop an accessible and affordable spectrophotometric technique in the visible range (λ = 514 nm) for the simple quantification of VCZ. The technique was based on VCZ-induced reduction of thionine (TH, red) to leucothionine (LTH, colorless) under alkaline conditions. The reaction showed a linear correlation over the range of 1.00 μg mL^-1 to 60.00 μg mL^-1 at room temperature, the limits of detection and quantification being 1.93 μg mL^-1 and 6.45 μg mL^-1, respectively. VCZ degradation products (DPs) according to ¹H and ¹³C-NMR spectrometric determinations not only showed good agreement with the ones previously reported (DP1 and DP2 - T. M. Barbosa, G. A. Morris, M. Nilsson, R. Rittner and C. F. Tormena, RSC Adv., 2017, DOI: 10.1039/c7ra03822d), but also revealed a new degradation product (DP3). Mass spectrometry not only confirmed the presence of LTH as a result of the VCZ DP-induced TH reduction, but also revealed the formation of a novel and stable Schiff base as a reaction product between DP1 and LTH. The latter finding became significant as it stabilizes the reaction for quantification purposes, by hindering LTH ↔TH redox reversibility. This analytical method was then validated according to the ICH Q2 (R1) guidelines, and additionally, it could be demonstrated as applicable for the reliable VCZ quantification in commercially available tablets. Importantly, it also represents a useful tool for detecting toxic threshold concentrations in human plasma from VCZ-treated patients, alerting when these risky limits are exceeded. In this way, this technique independent from sophisticated equipment, highly qualifies as a low-cost, reproducible, trustable, and non-laborious alternative method for VCZ measurements from different matrices.

Invasive aspergillosis in the patient with focal segmental glomerulosclerosis initiating hemodialysis: a case report and mini-review

Background

Invasive aspergillosis (IA) is a severe form of fungal infection caused by the genus Aspergillus in immunocompromised hosts and has a high mortality rate. End-stage kidney disease (ESKD) is one of the risk factors for developing fungal infection; however, the detailed clinical and treatment course of ESKD patients with IA has been scarcely reported, especially for the patient initiating hemodialysis (HD). Here, we experienced a patient under immunosuppressive therapy for focal segmental glomerulosclerosis (FSGS) who suffered from IA involving lung and brain and resulted in initiating HD.

Case presentation

A 66-year-old male patient with a history of suspected non-tuberculosis mycobacterial lung disease was initially admitted to the hospital with minimal change disease and subsequently diagnosed as FSGS with worsening urinary protein levels. The combined treatment including immunosuppressive treatments of cyclosporin and glucocorticoids and low-density lipoprotein apheresis was initiated, and then, he experienced the symptoms of dry cough, somnolence, and disorientation, which were subsequently diagnosed as IA involving lung and brain. The patient required renal replacement therapy, and maintenance HD was continued. Despite the intensive treatment with multiple antifungals of liposomal amphotericin B, voriconazole, micafungin, and amphotericin B, the pneumonia of the patient did not improve, and he subsequently passed away.

Conclusions

We report the case of the IA under immunosuppressive treatment, who was subsequently initiated maintenance HD. The detailed clinical course of medications used to treat the patient is presented with the literature review of IA in ESKD and HD patients and those with past acid-fast bacterial infections. The careful determination of the intensity of immunosuppression and monitoring of the patient’s symptoms and early definitive diagnosis is crucial in treating IA in immunocompromised hosts with ESKD or in HD under immunosuppressive treatment, as the mortality for these patients is suspected to be high despite the intensive treatment.

Voriconazole therapeutic drug monitoring and hepatotoxicity in critically ill patients: A nationwide multi-centre retrospective study

OBJECTIVES

To characterize trough concentrations (C_min) of voriconazole and associated hepatotoxicity, and to determine predictors of hepatotoxicity and identify high-risk groups in critically ill patients.

METHODS

This was a nationwide, multi-centre, retrospective study. C_min and hepatotoxicity were studied from 2015 to 2020 in 363 critically ill patients who received voriconazole treatment. Logistic regression and classification and regression tree (CART) models were used to identify high-risk patients.

RESULTS

Large interindividual variability was observed in initial voriconazole C_min and concentrations ranged from 0.1 mg/L to 18.72 mg/L. Voriconazole-related grade ≥2 hepatotoxicity developed in 101 patients, including 48 patients with grade ≥3 hepatotoxicity. The median time to hepatotoxicity was 3 days (range 1-24 days), and 83.2% of cases of hepatotoxicity occurred within 7 days of voriconazole initiation. Voriconazole C_min was significantly associated with hepatotoxicity. The CART model showed that significant predictors of grade ≥2 hepatotoxicity were C_min >3.42 mg/L, concomitant use of trimethoprim-sulfamethoxazole or tigecycline, and septic shock. The model predicted that the incidence of grade ≥2 hepatotoxicity among these high-risk patients was 48.3-63.4%. Significant predictors of grade ≥3 hepatotoxicity were C_min >6.87 mg/L, concomitant use of at least three hepatotoxic drugs, and septic shock; the predictive incidence among these high-risk patients was 22.7-36.8%.

CONCLUSION

Higher voriconazole C_min, septic shock and concomitant use of hepatotoxic drugs were the strongest predictors of hepatotoxicity. Plasma concentrations of voriconazole should be monitored early (as soon as steady state is achieved) to avoid hepatotoxicity.

Development of Physiology Based Pharmacokinetic Model to Predict the Drug Interactions of Voriconazole and Venetoclax

PURPOSE

Venetoclax (VEN), an anti-tumor drug that is a substrate of cytochrome P450 3A enzyme (CYP3A4), is used to treat leukemia. Voriconazole (VCZ) is an antifungal medication that inhibits CYP3A4. The goal of this study is to predict the effect of VCZ on VEN exposure.

METHOD

Two physiological based pharmacokinetics (PBPK) models were developed for VCZ and VEN using the bottom-up and top-down method. VCZ model was also developed to describe the effect of CYP2C19 polymorphism on its pharmacokinetics (PK). The reversible inhibition constant (Ki) of VCZ for CYP3A4 was calibrated using drug-drug interaction (DDI) data of midazolam and VCZ. The clinical verified VCZ and VEN model were used to predict the DDI of VCZ and VEN at clinical dosing scenario.

RESULT

VCZ model predicted VCZ exposure in the subjects of different CYP2C19 genotype and DDI related fold changes of sensitive CYP3A substrate with acceptable prediction error. VEN model can capture PK of VEN with acceptable prediction error. The DDI PBPK model predicted that VCZ increased the exposure of VEN by 4.5-9.6 fold. The increase in VEN exposure by VCZ was influenced by subject's CYP2C19 genotype. According to the therapeutic window, VEN dose should be reduced to 100 mg when co-administered with VCZ.

CONCLUSION

The PBPK model developed here could support individual dose adjustment of VEN and DDI risk assessment. Predictions using the robust PBPK model confirmed that the 100 mg dose adjustment is still applicable in the presence of VCZ with high inter-individual viability.

Impact of polymorphisms of pharmacokinetics-related genes and the inflammatory response on the metabolism of voriconazole

The effects of inflammatory responses and polymorphisms of the genes encoding cytochrome P450 (CYP) (CYP2C19 and CYP3A5), flavin-containing monooxygenase 3 (FMO3), pregnane X receptor (NR1I2), constitutive androstane receptor (NR1I3), and CYP oxidoreductase (POR) on the ratio of voriconazole (VRCZ) N-oxide to VRCZ (VNO/VRCZ) and steady-state trough concentrations (C0h ) of VRCZ were investigated. A total of 56 blood samples were collected from 36 Japanese patients. Results of multiple linear regression analyses demonstrated that the presence of the extensive metabolizer CYP2C19 genotype, the dose per administration, and the presence of the NR1I2 rs3814057 C/C genotype were independent factors influencing the VNO/VRCZ ratio in patients with CRP levels of less than 40 mg/L (standardized regression coefficients (SRC) = 0.448, -0.301, and 0.390, respectively; all p < .05). With regard to the concentration of VRCZ itself, in addition to the above factors, the presence of the NR1I2 rs7643645 G/G and rs3814055 T/T genotypes were found to be independent factors influencing the VRCZ C0h in these patients (SRC = -0.430, 0.424, -0.326, 0.406 and -0.455, respectively; all p < .05). On the contrary, in patients with CRP levels of at least 40 mg/L, no independent factors were found to affect VNO/VRCZ and VRCZ C0h . Inflammatory responses, and CYP2C19 and NR1I2 polymorphisms may be useful information for the individualization of VRCZ dosages.

Decrease of voriconazole trough levels during therapy with enteral nutrition: a case report

Background

Voriconazole (VRCZ) is the first-line therapy for chronic pulmonary aspergillosis and is available in both intravenous and oral formulations. The bioavailability of the oral form is estimated to be over 90% in healthy volunteers. Some drugs are reported to interact with enteral nutrition (EN), but there are few reports about the trough levels of VRCZ during EN therapy. Here, we describe changes in the VRCZ trough levels in a patient receiving continuous EN therapy.

Case presentation

The patient was a 58-year-old man with esophageal cancer and a history of partial pulmonary resection due to aspergilloma. He was taking oral VRCZ tablets and his VRCZ trough level was about 2 μg/mL before esophageal cancer surgery. Following esophagectomy, VRCZ was restarted on postoperative day 16. Crushed VRCZ tablets were administered via a jejunostomy tube because of swallowing difficulty. He was also receiving EN, which was interrupted only during the administration of VRCZ. When we checked his VRCZ level 5 days after restarting VRCZ, the trough level was 0.80 μg/mL. After increasing the VRCZ dose, reducing EN, and changing the administration route from jejunostomy tube to oral, his trough level increased to 1.87 μg/mL.

Conclusions

A decrease in the VRCZ trough level was observed when VRCZ was administered via a jejunostomy tube while the patient was receiving continuous EN. Careful monitoring of VRCZ levels is needed in such cases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40780-021-00237-4.

A Strategy for Hospital Pharmacists to Control Antimicrobial Resistance (AMR) in Japan

In Japan, there is concern regarding the relation between the inappropriate use of antibiotics and antibiotic resistance (AMR). Increased bacterial resistance is due in part to the inappropriate use of antimicrobial agents. The support of the pharmacist becomes important, and there is growing interest in antimicrobial stewardship to promote the appropriate and safe use of antimicrobials needed for the optimal selection of drugs, doses, durations of therapy, therapeutic drug monitoring (TDM), and implementations of cost containment strategies in Japan. Pharmacists should strive to disseminate the concept of "choosing wisely" in relation to all medicines, implement further interventions, and put them into practice. In this article, we present data for antimicrobial stewardship and Japan's AMR action plan, focusing on how pharmacists should be involved in enabling physicians to choose antimicrobials wisely.

Effects of Letermovir and/or Methylprednisolone Coadministration on Voriconazole Pharmacokinetics in Hematopoietic Stem Cell Transplantation: A Population Pharmacokinetic Study

Objective

The aim of this study was to identify factors affecting blood concentrations of voriconazole following letermovir coadministration using population pharmacokinetic (PPK) analysis in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients.

Methods

The following data were retrospectively collected: voriconazole trough levels, patient characteristics, concomitant drugs, and laboratory information. PPK analysis was performed with NONMEM^® version 7.4.3, using the first-order conditional estimation method with interaction. We collected data on plasma voriconazole steady-state trough concentrations at 216 timepoints for 47 patients. A nonlinear pharmacokinetic model with the Michaelis–Menten equation was applied to describe the relationship between steady-state trough concentration and daily maintenance dose of voriconazole. After stepwise covariate modeling, the final model was evaluated using a goodness-of-fit plot, case deletion diagnostics, and bootstrap methods.

Results

The maximum elimination rate (V_max) of voriconazole in patients coadministered letermovir and methylprednisolone was 1.72 and 1.30 times larger than that in patients not coadministered these drugs, respectively, resulting in decreased voriconazole trough concentrations. The developed PPK model adequately described the voriconazole trough concentration profiles in allo-HSCT recipients. Simulations clearly showed that increased daily doses of voriconazole were required to achieve an optimal trough voriconazole concentration (1–5 mg/L) when patients received voriconazole with letermovir and/or methylprednisolone.

Conclusions

The development of individualized dose adjustment is critical to achieve optimal voriconazole concentration, especially among allo-HSCT recipients receiving concomitant letermovir and/or methylprednisolone.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40268-021-00365-0.

Opportunities for Antimicrobial Stewardship Among Pediatric Patients Prescribed Combination Antifungal Therapy

OBJECTIVE

Combination antifungal therapy (CAF) may be prescribed to treat invasive fungal infections (IFIs). Data on the incidence of CAF among the pediatric population are limited. Antimicrobial stewardship for CAF includes therapeutic drug monitoring (TDM) and monitoring for adverse events. Primary outcome was to determine the incidence of CAF prescribed for documented proven, probable, and possible IFI. Secondary outcomes were to determine initial dose of antifungal therapy, determine incidence of adverse events, and evaluate our practice of TDM.

METHODS

Medical charts of patients who received CAF for proven, probable, or possible IFI within 6 years were reviewed. Patients age ≤18 years, prescribed CAF (defined as a second antifungal therapy started ≤72 hours of initial antifungal therapy) for at least 72 hours, and with normal liver function test results were included.

RESULTS

57 patients received CAF for 72 separate episodes: 35 episodes were proven IFI, 11 were probable IFI, and 26 were possible IFI. Initial dose of antifungal therapy varied, and 29.1% received a loading dose. A total of 10 patients experienced 14 adverse events that were related to antifungal therapy. In 63.8% of CAF episodes, TDM was conducted. Target antifungal concentrations were documented for 10 CAF episodes. Reason for discontinued of CAF was documented for 35 episodes. Of these episodes, 74% were discontinued after therapeutic antifungal concentrations were achieved.

CONCLUSIONS

There are opportunities for antimicrobial stewardship interventions in the method of TDM and monitoring for adverse events that could aid in management of CAF.

Association of Voriconazole Trough Plasma Concentration with Efficacy and Incidence of Hepatotoxicity in Iranian Patients with Hematological Malignancies

There are conflicting data regarding the association between plasma concentration of voriconazole (VCZ) and both efficacy and safety. This study investigates the association of VCZ trough plasma level with clinical efficacy and hepatotoxicity in the Iranian population suffering hematological malignancies. This cross-sectional study was performed on adult Iranian patients (age ≥ 18 years) with hematological malignancies undergoing treatment with oral or intravenous VCZ for proven or probable invasive aspergillosis. Plasma concentrations of VCZ were measured at two time points on day 4 and 14 during the study period. A total of 60 VCZ trough concentrations of 30 patients were drawn on days 4 and 14 after the initiation of treatment. There was no definite correlation between the mean plasma concentration of VCZ and VCZ dosage (p = 0.134, r = 0.280). In multivariable model, only plasma concentration of VCZ on day 14 was associated with the incidence of hepatotoxicity (p = 0.013; OR = 1.42, 95% CI = 1.07-3.24). Plasma trough concentration neither on day 4 nor on day 14 was related to the treatment response. No significant association was observed between the mean plasma concentration of VCZ and 3-month patients’ survival (p = 0.696). To conclude, VCZ trough concentration may not be a predictor of treatment response or 3-month patients’ survival. However, the wide inter- and intra-patient variability of VCZ plasma concentration coupled with the observed association between VCZ trough level and the incidence of hepatotoxicity would pose the question regarding the potential benefit of VCZ concentration monitoring.

Favorable Effects of Voriconazole Trough Concentrations Exceeding 1 μg/mL on Treatment Success and All-Cause Mortality: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis examined the optimal trough concentration of voriconazole for adult patients with invasive fungal infections. We used stepwise cutoffs of 0.5-2.0 μg/mL for efficacy and 3.0-6.0 μg/mL for safety. Studies were included if they reported the rates of all-cause mortality and/or treatment success, hepatotoxicity, and nephrotoxicity according to the trough concentration. Twenty-five studies involving 2554 patients were included. The probability of mortality was significantly decreased using a cutoff of ≥1.0 μg/mL (odds ratio (OR) = 0.34, 95% confidence interval (CI) = 0.15-0.80). Cutoffs of 0.5 (OR = 3.48, 95% CI = 1.45-8.34) and 1.0 μg/mL (OR = 3.35, 95% CI = 1.52-7.38) also increased the treatment success rate. Concerning safety, significantly higher risks of hepatotoxicity and neurotoxicity were demonstrated at higher concentrations for all cutoffs, and the highest ORs were recorded at 4.0 μg/mL (OR = 7.39, 95% CI = 3.81-14.36; OR = 5.76, 95% CI 3.14-10.57, respectively). Although further high-quality trials are needed, our findings suggest that the proper trough concentration for increasing clinical success while minimizing toxicity is 1.0-4.0 μg/mL for adult patients receiving voriconazole therapy.

Too Much of a Good Thing: Defining Antimicrobial Therapeutic Targets to Minimize Toxicity

Antimicrobials are a common cause of drug toxicity. Understanding the relationship between systemic antimicrobial exposure and toxicity is necessary to enable providers to take a proactive approach to prevent undesired drug effects. When an exposure threshold has been defined that predicts drug toxicity, therapeutic drug monitoring (TDM) can be performed to assure drug exposure does not exceed the defined threshold. Although some antimicrobials have well-defined dose-dependent toxicities, many other exposure-toxicity relationships have either not been well-defined or, in some cases, not been evaluated at all. In this review, we examine the relationship between exposures and toxicities for antibiotic, antifungal, and antiviral agents. Furthermore, we classify these relationships into four categories: known association between drug exposure and toxicity such that clinical implementation of a specific exposure threshold associated with toxicity for TDM is supported (category 1), known association between drug exposure and toxicity but the specific exposure threshold associated with toxicity is undefined (category 2), association between drug exposure and toxicity has been suggested but relationship is poorly defined (category 3), and no known association between drug exposure and toxicity (category 4). Further work to define exposure-toxicity thresholds and integrate effective TDM strategies has the potential to minimize many of the observed antimicrobial toxicities.

Simultaneous analysis of drugs administered to lung-transplanted patients using liquid chromatography-tandem mass spectrometry for therapeutic drug monitoring

Several drugs are administered to lung-transplanted patients, which are monitored using therapeutic drug monitoring (TDM). Therefore, we developed and validated a liquid chromatography-tandem mass spectrometry method to simultaneously analyze immunosuppressive drugs such as mycophenolic acid, antifungal drugs such as voriconazole and itraconazole, and its metabolite hydroxyitraconazole. Chromatographic separation was achieved using a C18 column and gradient flow of mobile phase comprising 20 mM aqueous ammonium formate and 20 mM ammonium formate-methanol solution. A simple protein precipitation treatment was performed using acetonitrile/methanol and mycophenolic acid-² H₃ , voriconazole-² H₃ , itraconazole-² H₄ , and hydroxyitraconazole-² H₄ as internal standards. The linearity ranges of mycophenolic acid, voriconazole, itraconazole, and hydroxyitraconazole were 100-20,000, 50-10,000, 5-1000, and 5-1000 ng/mL, respectively. The retention time of each target was less than 2 min. The relative errors in intra- and inter-day were within ±7.6%, the coefficient of variation was 8.9% or less for quality control low, medium, and high, and it was 15.8% or less for lower limit of quantitation. Moreover, the patient samples were successfully quantified, and they were within the linear range of measurements. Therefore, our new method may be useful for TDM in lung-transplanted patients.

Aspergillus flavus costochondritis following coronary artery bypass grafting: a case report and a brief review of literature

Bacterial sternal wound infections following cardiac surgery are not uncommon. However, sternal wound infection by a fungus is a rarity, and it warrants a correct diagnosis followed by specific treatment. We report a case of Aspergillus sternal wound infection with costochondritis following cardiac surgery, and briefly review the relevant literature.

Optimal trough concentration of voriconazole with therapeutic drug monitoring in children: A systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis was designed to determine the optimal trough concentration of voriconazole for children with invasive fungal infections (IFIs).

METHODS

We searched electronic databases (PubMed, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov and Japana Centra Revuo Medicina) for clinical studies describing the voriconazole trough concentration. We used stepwise cut-off values of 1.0-2.0 mg/L for efficacy and 3.0-6.0 mg/L for safety. The efficacy outcomes were treatment success and all-cause mortality, and the safety outcomes were hepatotoxicity, neurotoxicity and all-cause adverse events.

RESULTS

Nine studies involving 211 patients were included in the analysis. The probability of treatment success against IFIs was significantly increased at cut-off values of ≥1.0 mg/L (odds ratio [OR] = 2.65, 95% confidence interval [CI] = 1.20-5.87). Our analysis did not find any relationship between the trough concentration and survival. Concerning safety, the occurrence of any outcomes did not significantly differ according to the voriconazole trough concentrations at any cut-off value. However, in a subgroup analysis of Asian study locations, a significantly higher risk of hepatotoxicity was demonstrated at voriconazole trough cut-off values ≥ 3.0 mg/L (OR = 8.40, 95% CI = 1.36-51.92). Although a significant correlation between the voriconazole concentration and hepatotoxicity was evident in regression curve analysis, (y = 0.1198e^0.2298x), no correlation was demonstrated for neurotoxicity (y = 0.3913e^-0.008x).

CONCLUSION

Our findings suggest that the optimal trough concentration for increasing clinical success and minimizing hepatotoxicity during voriconazole therapy in children with IFIs, particularly for Asian populations, is 1.0-3.0 mg/L.

Factors Associated With Voriconazole Concentration in Pediatric Patients

BACKGROUND

Serum concentrations of voriconazole are difficult to predict, especially in pediatric patients, because of its complex pharmacokinetic characteristics. This study aimed to identify the factors associated with the concentration of voriconazole in pediatric patients.

METHODS

This cohort study was based on retrospective data collection and involved the administration of voriconazole to pediatric patients younger than 18 years, between January 2010 and August 2017. Electronic medical records of the patients were reviewed to collect demographic characteristics, voriconazole treatment regimen, and factors that could potentially influence voriconazole trough concentrations. A voriconazole trough serum concentration of less than 1.0 mcg/mL or greater than 5.5 mcg/mL was defined as outside the therapeutic range and was set as the outcome of this study.

RESULTS

Among the 114 patients enrolled, 61 patients were included in the analysis. Oral administration of a maintenance dose of voriconazole and C-reactive protein (CRP) level were significantly and independently associated with a low initial trough concentration of voriconazole (<1.0 mcg/mL). Alanine aminotransferase levels were a significant factor associated with a high initial trough concentration of voriconazole (>5.5 mcg/mL) after adjusting for sex, age, weight, and serum creatinine (odds ratio 5.42; 95% confidence interval 1.34-21.97).

CONCLUSIONS

Considering the variability of voriconazole concentrations in pediatric patients, monitoring certain parameters and considering the route of administration could help determine the therapeutic range of voriconazole and subsequently avoid unwanted effects.

Impact of Albumin and Omeprazole on Steady-State Population Pharmacokinetics of Voriconazole and Development of a Voriconazole Dosing Optimization Model in Thai Patients with Hematologic Diseases

This study aimed to identify factors that significantly influence the pharmacokinetics of voriconazole in Thai adults with hematologic diseases, and to determine optimal voriconazole dosing regimens. Blood samples were collected at steady state in 65 patients (237 concentrations) who were taking voriconazole to prevent or treat invasive aspergillosis. The data were analyzed using a nonlinear mixed-effects modeling approach. Monte Carlo simulation was applied to optimize dosage regimens. Data were fitted with the one-compartment model with first-order absorption and elimination. The apparent oral clearance (CL/F) was 3.43 L/h, the apparent volume of distribution (V/F) was 47.6 L, and the absorption rate constant (Ka) was fixed at 1.1 h⁻¹. Albumin and omeprazole ≥ 40 mg/day were found to significantly influence CL/F. The simulation produced the following recommended maintenance doses of voriconazole: 50, 100, and 200 mg every 12 h for albumin levels of 1.5–3, 3.01–4, and 4.01–4.5 g/dL, respectively, in patients who receive omeprazole ≤ 20 mg/day. Patients who receive omeprazole ≥ 40 mg/day and who have serum albumin level 1.5–3 and 3.01–4.5 g/dL should receive voriconazole 50 and 100 mg, every 12 h, respectively. Albumin level and omeprazole dosage should be carefully considered when determining the appropriate dosage of voriconazole in Thai patients.

Effect of Therapeutic Drug Monitoring and Cytochrome P450 2C19 Genotyping on Clinical Outcomes of Voriconazole: A Systematic Review

Objectives

To examine current knowledge on the clinical utility of therapeutic drug monitoring (TDM) in voriconazole therapy, the impact of CYP2C19 genotype on voriconazole plasma concentrations, and the role of CYP2C19 genotyping in voriconazole therapy.

Data Sources

Three literature searches were conducted for original reports on (1) TDM and voriconazole outcomes and (2) voriconazole and CYP2C19 polymorphisms. Searches were conducted through EMBASE, MEDLINE/PubMed, Scopus, and Cochrane Central Register of Controlled Trials from inception to June 2020.

Study Selection and Data Extraction

Randomized controlled trials, cohort studies, and case series with ≥10 patients were included. Only full-text references in English were eligible.

Data Synthesis

A total of 63 studies were reviewed. TDM was recommended because of established concentration and efficacy/toxicity relationships. Voriconazole trough concentrations ≥1.0 mg/L were associated with treatment success; supratherapeutic concentrations were associated with increased neurotoxicity; and hepatotoxicity associations were more prevalent in Asian populations. CYP2C19 polymorphisms significantly affect voriconazole metabolism, but no relationship with efficacy/safety were found. Genotype-guided dosing with TDM was reported to increase chances of achieving therapeutic range.

Relevance to Patient Care and Clinical Practice

Genotype-guided dosing with TDM is a potential solution to optimizing voriconazole efficacy while avoiding treatment failures and common toxicities.

Conclusions

Voriconazole plasma concentrations and TDM are treatment outcome predictors, but research is needed to form a consensus target therapeutic range and dosage adjustment guidelines based on plasma concentrations. CYP2C19 polymorphisms are a predictor of voriconazole concentrations and metabolism, but clinical implications are not established. Large-scale, high-methodological-quality trials are required to investigate the role for prospective genotyping and establish CYP2C19-guided voriconazole dosing recommendations.

Voriconazole therapeutic drug monitoring in critically ill patients improves efficacy and safety of antifungal therapy

Since voriconazole plasma trough concentration (VPC) is related to its efficacy and adverse events, therapeutic drug monitoring (TDM) is recommended to perform. However, there is no report about the data of voriconazole TDM in critically ill patients in China. This retrospective study was performed to determine whether voriconazole TDM was associated with treatment response and/or voriconazole adverse events in critically ill patients, and to identify the potential risk factors associated with VPC. A total of 216 critically ill patients were included. Patients were divided into two groups: those underwent voriconazole TDM (TDM group, n = 125) or did not undergo TDM (non-TDM group, n = 91). The clinical response and adverse events were recorded and compared. Furthermore, in TDM group, multivariate logistic regression analysis was performed to identify the possible risk factors resulting in the variability in initial VPC. The complete response in the TDM group was significantly higher than that in the non-TDM group (P = .012). The incidence of adverse events strongly associated with voriconazole in the non-TDM group was significantly higher than that in the TDM group (19.8% vs 9.6%; P = .033). The factors, including age (OR 0.934, 95% CI: 0.906-0.964), male (OR 5.929, 95% CI: 1.524-23.062), serum albumin level (OR 1.122, 95% CI: 1.020-1.234), diarrhoea (OR 4.953, 95% CI: 1.495-16.411) and non-intravenous administration (OR 4.763, 95% CI: 1.576-14.39), exerted the greatest effects on subtherapeutic VPC (VPC < 1.5 mg/L) in multivariate analysis. Intravenous administration (OR 7.657, 95% CI: 1.957-29.968) was a significant predictor of supratherapeutic VPC (VPC > 4.0 mg/L). TDM can result in a favourable clinical efficacy and a lower incidence of adverse events strongly associated with voriconazole in critically ill patients. Subtherapeutic VPC was closely related to younger age, male, hyperalbuminaemia, diarrhoea and non-intravenous administration, and intravenous administration was a significant predictor of supratherapeutic VPC.

Effects of antifungal stewardship using therapeutic drug monitoring in voriconazole therapy on the prevention and control of hepatotoxicity and visual symptoms: A multicentre study conducted in Japan

Background

Hepatotoxicity and visual symptoms are common adverse effects (AEs) of voriconazole therapy.

Objective

To retrospectively evaluate the effects of treatment modification based on therapeutic drug monitoring on AEs in patients undergoing voriconazole therapy.

Methods

The target voriconazole trough concentration (C_min) was 1‐5 µg/mL. Receiver operating characteristic curves were used to determine C_min cut‐offs for AEs.

Results

A total of 401 patients were included. Among 108 patients with high initial C_min, voriconazole was discontinued in 32 and the dose was reduced in 71. Among 44 patients with low initial C_min, voriconazole was discontinued in 4 and the dose was increased in 19. Hepatotoxicity occurred in 6.0% of patients, after a median of 10 days. Visual symptoms were evident in 9.5% of patients after a median of 4 days. Initial C_min was significantly associated with visual symptoms but not hepatotoxicity, which suggested the effect of treatment modification on hepatotoxicity. However, both hepatotoxicity and visual symptoms were significantly correlated with C_min at the onset of AEs, and the C_min cut‐offs were 3.5 μg/mL for hepatotoxicity and 4.2 μg/mL for visual symptoms. Voriconazole was discontinued after the occurrence of AEs in 62.5% of patients with hepatotoxicity but only 26.3% of patients with visual symptoms. With dose adjustment, treatment was completed in 8/9 patients with hepatotoxicity and 27/28 patients with visual symptoms.

Conclusions

A significant preventive effect was demonstrated on hepatotoxicity, but not on visual symptoms because of earlier occurrence. With treatment modification after the occurrence of AEs, most patients completed therapy.

Variability and exposure-response relationships of isavuconazole plasma concentrations in the Phase 3 SECURE trial of patients with invasive mould diseases

Objectives

This analysis evaluated the variability of isavuconazole plasma concentrations between subjects and between sampling times, and assessed their relationship to outcomes for subjects with invasive fungal disease (IFD) in the SECURE trial.

Methods

Isavuconazole-treated subjects received 372 mg of isavuconazonium sulphate (corresponding to 200 mg of isavuconazole) three times daily for 2 days, then once daily. Plasma samples were collected after day 4 and analysis sets were constructed as follows: analysis set 1 included all samples from subjects with proven/probable/possible IFD who received ≥1 dose of isavuconazole; analysis set 2 included samples from subjects in analysis set 1 who had provided >1 sample; and analysis set 3 included samples from subjects in analysis set 1 with proven/probable invasive aspergillosis. Assessments included overall distributions of plasma concentrations and variability between samples (analysis sets 1 and 2) as well as relationships to outcomes [all-cause mortality (day 42), overall response (end of treatment) and treatment-emergent adverse events; analysis sets 1 and 3].

Results

Analysis sets 1, 2 and 3 included samples from 160, 97 and 98 subjects, respectively. Trough concentrations for each were distributed similarly [mean (SD): 3406.6 (1511.5), 3495.6 (1503.3) and 3368.1 (1523.2) ng/mL, respectively]. The mean coefficient of variation between samples in analysis set 2 was 23.2%; differences between concentrations in first samples and subsequent samples were <2-fold for 85/97 subjects. In quartiles of subject data, no concentration-dependent relationships were observed for efficacy or safety.

Conclusions

Plasma concentrations of isavuconazole were reasonably consistent between subjects and sampling times, and were not associated with differences in outcomes.

Quality of therapeutic drug monitoring guidelines is suboptimal: an evaluation using the Appraisal of Guidelines for Research and Evaluation II instrument

OBJECTIVES

Although therapeutic drug monitoring (TDM) guidelines are available, systematic evaluations of their methodological quality are scarce. This study aimed to assess the quality of current TDM guidelines using the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument.

STUDY DESIGN AND SETTING

We performed a systematic search to identify the relevant TDM guidelines in PubMed, EMBASE, CNKI, Wan Fang Database, CBM, VIP, four main guideline databases (NICE, NGC, GIN, and WHO guideline databases), and official websites of the governments and societies associated with TDM from the inception date to May 2018. Four independent appraisers rated the quality of each TDM guideline using the AGREE II instrument, and the mean score of each AGREE II item was calculated. The overall agreement among the appraisers was evaluated using the intraclass correlation coefficient (ICC).

RESULTS

Twenty-eight TDM guidelines satisfied the eligibility criteria from among 12,235 references. The overall agreement among the appraisers was substantial (0.700-0.880). The mean scores for the six AGREE II domains were scope and purpose, 67.7% (95% CI, 64.0-71.4%); stakeholder involvement, 39.8% (95% CI, 33.3-46.3%); rigor of development, 36.0% (95% CI, 28.1-43.9%); clarity and presentation, 61.6% (95% CI, 55.7-67.4%); applicability, 30.6% (95% CI, 26.4-34.8%); and editorial independence, 49.2% (95% CI, 40.0-58.6%). The reviewers recommended only four guidelines, and most of the TDM guidelines were rated as "recommended with modifications."

CONCLUSION

Overall, the quality of TDM guidelines is suboptimal according to the evaluation using the AGREE II instrument. The domains of applicability, rigor of development, stakeholder involvement, and editorial independence of the guidelines need to be reported. In addition, guideline developers closely adhering to the AGREE II instrument and the Grading of Recommendations Assessment Development and Evaluation system are required to draft high-quality and reliable TDM guidelines.

Therapeutic drug monitoring of systemic antifungal agents: a pragmatic approach for adult and pediatric patients

Introduction: Therapeutic drug monitoring (TDM) has been shown to optimize the management of invasive fungal infections (IFIs), particularly for select antifungal agents with a well-defined exposure-response relationship and an unpredictable pharmacokinetic profile or a narrow therapeutic index. Select triazoles (itraconazole, voriconazole, and posaconazole) and flucytosine fulfill these criteria, while the echinocandins, fluconazole, isavuconazole, and amphotericin B generally do not do so. Given the morbidity and mortality associated with IFIs and the challenges surrounding the use of currently available antifungal agents, TDM plays an important role in therapy.Areas covered: This review seeks to describe the rationale for TDM of antifungal agents, summarize their pharmacokinetic and pharmacodynamic properties, identify treatment goals for efficacy and safety, and provide recommendations for optimal dosing and therapeutic monitoring strategies.Expert opinion: Several new antifungal agents are currently in development, including compounds from existing antifungal classes with enhanced pharmacokinetic or safety profiles as well as agents with novel targets for the treatment of IFIs. Given the predictable pharmacokinetics of these newly developed agents, use of routine TDM is not anticipated. However, expanded knowledge of exposure-response relationships of these compounds may yield a role for TDM to improve outcomes for adult and pediatric patients.

Population Pharmacokinetics of Voriconazole and Optimization of Dosage Regimens Based on Monte Carlo Simulation in Patients With Liver Cirrhosis

Because voriconazole metabolism is highly influenced by liver function, the dose regimen of voriconazole should be carefully assessed in patients with liver cirrhosis. We aimed to identify significant factors associated with plasma concentrations. Blood samples were collected from patients with liver cirrhosis who received voriconazole, and voriconazole concentrations were determined. One-compartment model with first-order absorption and elimination appropriately characterized the in vivo process of voriconazole. The typical population value of voriconazole clearance (CL) was 1.45 L/h and the volume of distribution (V) was 132.12 L. The covariate analysis identified that CYP2C19 gene phenotype and Child-Pugh classification were strongly associated with CL and body weight had a significant influence on V. The results of the Monte Carlo simulation suggested that CYP2C19 gene phenotype was a critical factor for determining voriconazole dosage in patients with liver cirrhosis. The extensive metabolizer patients with Aspergillus fumigatus infections could be treated effectively with a recommended dose of 75 mg twice daily in mild to moderate liver cirrhosis and 100 mg once daily in moderate severe liver cirrhosis. However, the recommended dosage for Candida albicans infections patients was not achieved in present study.

Exophiala dermatitidis Fungemia Diagnosed Using Time-of-flight Mass Spectrometry during Chemotherapy for Malignant Lymphoma and Successful Treatment with Voriconazole

Infectious diseases, including those caused by fungi, remain important issues in patients receiving malignant lymphoma chemotherapy. We herein report a rare case of Exophiala dermatitidis fungemia during chemotherapy in a 67-year-old woman admitted to our hospital. She had a fever that could not be resolved despite antifungal therapy. Yeast-like fungi were detected in blood culture samples, but biochemical identification was difficult. E. dermatitidis, a black mold, was identified using time-of-flight mass spectrometry. The patient finally improved after her treatment was switched to voriconazole. Fungal infection is difficult to diagnose and treat, but this novel approach can improve patients' outcomes.

Clinical Pharmacokinetics of Second-Generation Triazoles for the Treatment of Invasive Aspergillosis and Candidiasis

Second-generation triazoles were developed in response to the quest for more efficacious and safer therapeutic options for the treatment of severe systemic aspergillosis and candidiasis. These agents include voriconazole, posaconazole, isavuconazole, and ravuconazole. The aim of this review was to present and compare the pharmacokinetic characteristics of second-generation triazoles for the treatment of invasive aspergillosis and candidiasis, emphasizing their clinical implications. The MEDLINE, Scopus, EBSCO, Google Scholar, and SCIndeks databases were searched using advanced search options, including the names of second-generation triazoles and pharmacokinetic terms as keywords. The intravenous administration of voriconazole, posaconazole, and isavuconazole results in stable pharmacokinetics of these drugs, with mostly predictable variations influenced by common and usually known factors in routine clinical settings. The high oral bioavailability of isavuconazole and, to some extent, voriconazole makes them suitable for intravenous-to-oral switch strategies. Except for intravenous voriconazole (due to the accumulation of the toxic vehicle hydroxypropyl betadex), dose reduction of second-generation triazoles is not needed in patients with renal failure; patients with hepatic insufficiency require dose reduction only in advanced disease stages. The introduction of therapeutic drug monitoring could aid attempts to optimize the blood concentrations of triazoles and other drugs that are known to or that possibly interact, thus increasing treatment efficacy and safety. There is a need for new studies that are designed to provide useful data on second-generation triazole pharmacokinetics, particularly in special circumstances such as central nervous system and ocular infections, infections in newborns and infants, and in subjects with genetic polymorphisms of metabolizing enzymes.

High-Resolution Melting Assay for Genotyping Variants of the CYP2C19 Enzyme and Predicting Voriconazole Effectiveness

Voriconazole is a triazole antifungal agent recommended as primary treatment for invasive aspergillosis, as well as some other mold infections. However, it presents some pharmacokinetic singularities that lead to a great variability intra- and interindividually, nonlinear pharmacokinetics, and a narrow therapeutic range. Most experts have recommended tracing the levels of voriconazole in patients when receiving treatment. This azole is metabolized through the hepatic enzyme complex cytochrome P450 (CYPP450), with the isoenzyme CYP2C19 being principally involved. Allelic variations (polymorphisms) of the gene that encodes this enzyme are known to contribute to variability in voriconazole exposure. Three different allelic variants, CYP2C19*17, CYP2C19*2, and CYP2C19*3, could explain most of the phenotypes related to the voriconazole metabolism and some of its pharmacokinetic singularities. We designed a rapid molecular method based on high-resolution melting to characterize these polymorphisms in a total of 142 samples, avoiding sequencing. Three PCRs were designed with similar cycling conditions to run simultaneously. The results showed that our method represents a fast, accurate, and inexpensive means to study these variants related to voriconazole metabolism. In clinical practice, this could offer a useful tool to individually optimize therapy and reduce expenses in patients with fungal infections.

Pulmonary infectious complications after hematopoietic stem cell transplantation: a practical guide to clinicians

PURPOSE OF REVIEW

The current review highlights the most relevant articles on lung infections following hematopoietic stem cell transplantation (HCT) published over the last year. Between 30 and 50% of HCT recipients will develop pulmonary infiltrates. These pulmonary complications may be infectious (caused by virus, bacteria, fungi, or protozoa) or noninfectious (e.g., fluid overload, heart failure, transfusion reactions like transfusion associated lung injury and transfusion-associated circulatory overload, drug reactions, engraftment syndrome, idiopathic pneumonia syndrome, diffuse alveolar hemorrhage, cryptogenic organizing pneumonia, and bronchiolitis obliterans syndrome).

RECENT FINDINGS

New data on the yield of bronchoscopy and bronchoalveolar lavage (BAL), the prevalence and clinical manifestations of respiratory viruses and the usefulness of molecular techniques for diagnosis have been published. In addition, guidelines or meta-analyses on the management of neutropenic fever, serological diagnosis of fungal infections and diagnosis and management of Pneumocystis and aspergillosis have been published.

SUMMARY

Respiratory viruses are important pathogens after HCT. PCR in the BAL is becoming the diagnostic modality of choice for a variety of infections. The best approach for the empirical management of pulmonary infiltrates following HCT remains to be defined.

Impact of CYP3A5, POR, and CYP2C19 Polymorphisms on Trough Concentration to Dose Ratio of Tacrolimus in Allogeneic Hematopoietic Stem Cell Transplantation

Single nucleotide polymorphisms in drug-metabolizing genes may affect tacrolimus pharmacokinetics. Here, we investigated the influence of genotypes of CYP3A5, CYP2C19, and POR on the concentration/dose (C/D) ratio of tacrolimus and episodes of acute graft-versus-host disease (GVHD) in Japanese recipients of allogeneic hematopoietic stem cell transplantation (HSCT). Thirty-six patients receiving the first HSCT using tacrolimus-based GVHD prophylaxis were enrolled with written informed consent. During continuous intravenous infusion, HSCT recipients carrying the CYP3A5*1 allele, particularly those with at least one POR*28 allele, had a significantly lower tacrolimus C/D ratio throughout all three post-HSCT weeks compared to that in recipients with POR*1/*1 (p < 0.05). The CYP3A5*3/*3 genotype and the concomitant use of voriconazole were independent predictors of an increased tacrolimus C/D ratio during the switch from continuous intravenous infusion to oral administration (p < 0.05). In recipients receiving concomitant administration of voriconazole, our results suggest an impact of not only CYP3A5 and CYP2C19 genotypes, but also plasma voriconazole concentration. Although switching from intravenous to oral administration at a ratio of 1:5 was seemingly appropriate in recipients with CYP3A5*1, a lower conversion ratio (1:2-3) was appropriate in recipients with CYP3A5*3/*3. Our results suggest that CYP3A5, POR, and CYP2C19 polymorphisms are useful biomarkers for individualized dosage adjustment of tacrolimus in HSCT recipients.

Interpersonal Factors in the Pharmacokinetics and Pharmacodynamics of Voriconazole: Are CYP2C19 Genotypes Enough for Us to Make a Clinical Decision?

Background:

Invasive mycoses are serious infections with high mortality and increasing inci-dence. Voriconazole, an important drug to treat invasive mycosis, is metabolized mainly by the cytochrome P450 family 2 subfamily C member 19 enzyme (CYP2C19) and is affected by the genotypes of CYP2C19.

Objective:

We reviewed studies on how genotypes affect the pharmacokinetics and pharmacodynamics of voriconazole, and attempted to determine a method to decide on dosage adjustments based on genotypes, after which, the main characteristic of voriconazole was clarified in details. The pharmacokinetics of voriconazole are influenced by various inter and intrapersonal factors, and for certain populations, such as geriatric patients and pediatric patients, these influences must be considered. CYP2C19 genotype represents the main part of the interpersonal variability related to voriconazole blood concentrations. Thus monitoring the concentration of voriconazole is needed in clinical scenarios to minimize the negative influences of inter and intrapersonal factors. Several studies provided evidence on the stable trough concentration range from 1-2 to 4-6 mg/L, which was combined to consider the efficacy and toxicity. However, the therapeutic drug concentration needs to be narrowed down and evaluated by large-scale clinical trials.

Conclusion:

Though there is insufficient evidence on the relationship between CYP2C19 genotypes and clinical outcomes, there is a great potential for the initial voriconazole dose selection to be guided by the CYP2C19 genotype. Finally, voriconazole therapeutic drug monitoring is essential to provide patient-specific dosing recommendations, leading to more effective anti-fungal regimens to increase clinical effica-cy and reduce adverse drug reactions.

Individualized Medication of Voriconazole: A Practice Guideline of the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society

Supplemental Digital Content is Available in the Text.

Background:

Voriconazole (VRZ) is a second-generation triazole antifungal agent with broad-spectrum activity. It is available in both intravenous and oral formulations, and is primarily indicated for treating invasive aspergillosis. The most commonly used dose for adults is 4 mg/kg or 200 mg twice daily. VRZ presents nonlinear pharmacokinetics in adults, whereas drug–drug interactions and cytochrome P450 2C19 (CYP2C19) polymorphism are of great concern for VRZ. Because the liquid chromatography method has been widely used for measuring VRZ blood concentration, and target VRZ blood concentration has been recommended in some guidelines regarding efficacy and safety, therapeutic drug monitoring is considered as a useful tool for VRZ-individualized medication. Also, the CYP2C19 genotype test is available for guiding relevant drugs use in some health care facilities. Our objective was to develop an evidence-based practice guideline for VRZ-individualized medication.

Methods:

We followed the latest guideline definition from the Institute of Medicine and referred to the World Health Organization handbook for guideline development. The guideline was initially registered in the International Practice Guidelines Registry Platform (IPGRP-2015CN001). The guideline is, in principle, targeted at all Chinese health care providers. The quality of evidence and strength of the recommendations were assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) method.

Results:

Twenty-six recommendations were formulated regarding therapeutic drug monitoring, special groups of patients, drug safety, off-indication use, and drug–drug interactions. Of them, 12 were strong recommendations. Most quality of evidence was low, very low, or expert opinions.

Conclusions:

We developed an evidence-based practice guideline for VRZ-individualized medication, which provided comprehensive and practical recommendations for health care providers. The development of the guideline exposed several research gaps to improve VRZ use.