Therapeutic Drug Monitoring Of Voriconazole Research Articles

P-1235. HPLC-UV method to establish rapid therapeutic drug monitoring of voriconazole in outpatients

Abstract Background Voriconazole (VRCZ) has non-linear pharmacokinetics, so personalized dosing based on pharmacokinetics is important. Approximately 20% of Asians are poor metabolizers of CYP2C19. In Japan, challenges include rapid measurement of VRCZ blood levels, feedback of results to physicians, and rapid therapeutic drug monitoring (TDM). The aim of this study was to evaluate the rapid TDM implementation system for VRCZ in outpatients. Methods Measurement of outpatient VRCZ TDM was started at Kochi medical school Hospital in January 2024 based on the blood concentration measurement flow by LM1010 high performance liquid chromatograph (HPLC-UV, Hitachi High-Tech Science Corporation). From January to April 2024, we compared the trough values of VRCZ and the reporting time of blood concentration measurement results after sample collection using the conventional externally requested measurement method (Method A) and the measurement method we constructed (Method B). In addition, we investigated the occurrence of hepatotoxicity from the perspective of preventing adverse events. Results The trough concentration of VRCZ were 2.97±1.15 mg/L for method A (n=7) and 3.15±1.25 mg/L for method B (n=15) ,p=0.75. The time required to report VRCZ blood concentration measurement results was significantly shorter (Method A (n=7): 78.9±10.4 h vs. Method B (n=7): 0.44±0.02 h (p< 0.05). No hepatotoxicity was observed during treatment in TDM outpatients who underwent rapid VRCZ measurement. Conclusion It is suggested that rapid determination of blood concentration of VRCZ by HPLC-UV will be an effective tool for TDM implementation and medical care support. Disclosures All Authors: No reported disclosures

Evaluation of voriconazole therapeutic drug monitoring in malignant hematology patients.

Malignant hematology (MH) patients are susceptible to invasive fungal infections due to prolonged neutropenia and immunosuppressive therapies, which may require voriconazole therapy. Although voriconazole therapeutic drug monitoring (TDM) is common, evidence describing this practice is limited. The primary objective of this study was to describe the current practice of voriconazole TDM in MH patients at the Princess Margaret Cancer Centre (PM). A retrospective chart review was conducted for MH inpatients initiated on voriconazole at PM between November 1st, 2019 and November 13th, 2020. Data regarding voriconazole doses, levels, dose changes, and adverse effects were collected. The primary endpoint was the proportion of patients with initial voriconazole levels within therapeutic range (1-5 mg/L). Fifty-six patients were included in the study. The most common reason for starting voriconazole was possible invasive fungal infection (44 patients, 78.6%). Fifty-one patients (91.1%) received a loading dose of voriconazole, averaging 386.5 ± 78.5 mg. The average maintenance dose was 242.1 ± 45.7 mg. An average of 2.6 ± 2.9 levels were drawn per patient with an average level of 3.2 ± 2.4 mg/L. Forty-one patients (73.2%) had an initial voriconazole level within therapeutic range and 90 out of 145 total levels (62.1%) were within therapeutic range. There were 52 dose modifications made; 31 (60.8%) doses adjusted, 12 (23.5%) doses held, and 9 (17.6%) doses discontinued. For the 31 dose adjustments, 26 (83.9%) had a level redrawn and 17 (65.4%) of those levels were within therapeutic range. Twenty-three (41.1%) patients developed adverse effects, 8 (34.8%) of which were associated with supratherapeutic levels. Of these 23 patients, 19 (33.9%) experienced transaminitis, 3 (5.4%) experienced both transaminitis and neurotoxicity, and 1 (1.8%) experienced photopsia. Overall, 41 (73.2%) patients achieved an initial voriconazole level within therapeutic range. Of these 41 patients, 30 (73.2%) remained within therapeutic range for the duration of their inpatient voriconazole therapy. These findings suggest that the current practice of voriconazole TDM at our institution is yielding largely positive results, but still has room for improvement.

Voriconazole therapeutic drug monitoring including analysis of CYP2C19 phenotype in immunocompromised pediatric patients with invasive fungal infections

PurposeTherapeutic drug monitoring (TDM) of voriconazole (VCZ) should be mandatory for all pediatric patients with invasive fungal infections (IFIs). The narrow therapeutic index, inter-individual variability in VCZ pharmacokinetics, and genetic polymorphisms cause achieving therapeutic concentration during therapy to be challenging in this population.MethodsThe study included 44 children suffering from IFIs treated with VCZ. Trough concentrations (Ctrough) of VCZ ware determined by the HPLC-FLD method. Identification of the CYP2C19*2 and CYP2C19*17 genetic polymorphisms was performed by PCR–RFLP. The correlation between polymorphisms and VCZ Ctrough was analyzed. Moreover, the effect of factors such as dose, age, sex, route of administration, and drug interactions was investigated.ResultsVCZ was administered orally and intravenously at a median maintenance dosage of 14.7 mg/kg/day for a median of 10 days. The VCZ Ctrough was highly variable and ranged from 0.1 to 6.8 mg/L. Only 45% of children reached the therapeutic range. There was no significant association between Ctrough and dosage, age, sex, route of administration, and concomitant medications. The frequencies of variant phenotype normal (NM), intermediate (IM), rapid (RM) and ultrarapid metabolizers (UM) were 41%, 18%, 28%, and 13%, respectively. Ctrough of VCZ were significantly higher in NM and IM groups compared with RM, and UM groups.ConclusionThe Ctrough of VCZ is characterized by inter-individual variability and a low rate of patients reaching the therapeutic range. The significant association exists in children between VCZ Ctrough and CYPC19 phenotype. The combination of repeated TDM and genotyping is necessary to ensure effective treatment.

A Perspective Study on Therapeutic Drug Monitoring of Voriconazole in Pediatric Patients with Hematologic Disorders

Background: The incidence of invasive aspergillosis and the administration of voriconazole have risen among immunocompromised patients. Objectives: This study aimed to evaluate serum voriconazole concentration and its corresponding influential factors in pediatric patients with hematologic disorders. Methods: A total of 132 blood samples were collected from 44 pediatric patients with hematologic disorders infected with invasive aspergillosis and treated with voriconazole. Among these patients, 20.5% were classified as having proven invasive aspergillosis, 77.2% as probable, and 2.3% as possible. Voriconazole serum levels were evaluated using HPLC on the 3rd, 5th, and 7th days of treatment. Genotyping of the CYP2C19 alleles (*2, *3, and *17) was performed, and demographic and clinical data were gathered from records between 2018 to 2020. Results: The voriconazole concentration in 70.5% of patients and 77.3% of treatment cases (complete or partial) ranged from 1 to 5.5 µg/mL. Adverse events were observed in 4.5% of the patients. Genotyping of CYP2C19 genes revealed CYP2C19*1*1 (5.4%), CYP2C19*1*17 (16.2%), CYP2C19*1*2 (51.4%), and CYP2C19*2*17 (27%). Multivariate analysis using linear regression demonstrated that serum voriconazole concentration increased by 0.037 µg/mL per year of age and by 0.06 µg/mL for each unit increase in C-reactive protein (on the 3rd day of voriconazole therapy). Additionally, an increase in alanine aminotransferase level by 1 unit decreased the mean voriconazole concentration by 0.03 µg/mL. Of these patients, 65.9% were completely treated, 11.4% were partially treated, and 22.7% died. Conclusions: Serum voriconazole concentrations varied among pediatric hematologic patients receiving standard doses, with age, C-reactive protein, and alanine aminotransferase levels affecting the concentration of voriconazole in the sera of pediatric patients.

WHICH TOOL IS THE BEST GUIDE OPTIMIZE THE VORICONAZOLE DOSAGE: THERAPEUTIC DRUG MONITORING OR CYTOCHROME P450 POLYMORPHISM?

Voriconazole (VCZ) is the drug of choice for invasive aspergillosis (IA). However, narraow therapeutic range and variable pharmacokinetics can effect the success of the therapy. VCZ serum concentration is influenced by several factor including CYP450 polymorphisms primarily by CY2C19. Therapeutic drug monitoring (TDM) of VCZ is highly recommended to check adequate serum concentrations. Herein, we investigated the usefulness of detecting CYP450 polymorphism. Patients with hematological malignancies were included in the study.CYP450 polymorphisms which are responsible for metabolism of VCZ were investigated using RT-PCR. TDM of VCZ was peformed usingLC/MS/MS.11 patients were included in the study. Frequencies of CYP2C19 genotypes are 27% for intermediate metabolizer; 36% rapid metabolizer, 18% for ultra rapid metabolizer, 18% for normal metabolizer. Two patients experienced dose related side effects and one of these patient’s voriconazole blood concentration was supratherapeuticAlthough VCZ is the drug of choice for thetreatment of IA, the variabality of the pharmacokinetics can influence the success of therapy significantly. Therefore implementing the pharmacogenetic testing and therapeutic drug monitoring to clinical practice might help clinicians to provide improved care to patients and improve treatment outcomes.

Therapeutic Drug Monitoring of Voriconazole in Critically Ill Pediatric Patients: A Single-Center Retrospective Study.

Voriconazole pharmacokinetics are highly variable in pediatricpatients, and the optimal dosage has yet to be determined. The purpose of this study was to describe voriconazole pharmacokinetic and pharmacodynamic targets achieved and evaluate the efficacy and safety of voriconazole for critically ill pediatrics. This is a single-center retrospective study conducted at a pediatric intensive care unit at a tertiary/quaternary hospital. Pediatrics admitted to the pediatric intensive care unit and who received voriconazole for a proven or suspected fungal infection with at least one measured trough concentration were included. The primary outcomes included the percentage of pediatric patients who achieved the pharmacokinetic and pharmacodynamic targets. Secondary outcomes included assessing the correlation between voriconazole trough concentrations and clinical/microbiological outcomes. All statistical analyses were performed using the R statistical software and Microsoft Excel. Multiple logistic regression was used to assess the predictors of both clinical and microbiologic cures. Multiple linear regression was used to determine significant factors associated with trough concentrations. A total of 129 voriconazole trough concentrations were measured from 71 participants at steady state after at least three doses of voriconazole. The mean (± standard deviation) of the first and second trough concentrations were 2.9 (4.2) and 2.3 (3.3) mg/L, respectively. Among the first trough concentrations, only 33.8% were within the therapeutic range (1-5 mg/L), 46.5% were below the therapeutic range, and 19.7% were above the therapeutic range. A clinical cure occurred in 78% of patients, while a microbiologic cure occurred in 80% of patients. Voriconazole trough concentrations vary widely in critically ill pediatric patients and only a third of the patients achieved therapeutic concentrations with initial doses.

Hypokalemia and Hyponatremia in Adult Patients Receiving Voriconazole Therapeutic Drug Monitoring.

Hypokalemia and hyponatremia are common but easily ignored adverse events in treatment with voriconazole (VCZ) that can lead to serious consequences. We intend to investigate the incidence of VCZ-induced hypokalemia and hyponatremia and their risk factors based on real-world data. A prospective study was conducted. A total of 272 patients with 414 VCZ plasma trough concentrations (C0) and VCZ N-oxide concentrations (CN) were included. The incidence of hypokalemia was 18.0% (48/266). A total of 81.2% (39/48) of patients developed hypokalemia within 14days, whereas 56.2% (27/48) of patients developed hypokalemia within 1week. The proportion of female patients in the hypokalemia group was higher than that in the nonhypokalemia group, as was the proportion of patients receiving intravenous VCZ. In the multivariate analysis, the independent risk factors for hypokalemia were sex, combined use of antibiotics, and VCZ CN/C0. The incidence of hyponatremia was 7.9% (21/266). The proportion of patients over 47years of age in the hyponatremia group was 71.4% (15/21). The number of days of VCZ use in the hyponatremia group was greater than that in the nonhyponatremia group. A total of 47.6% (10/21) of patients in the hyponatremia group had supratherapeutic VCZ C0 (>5.0µg/mL). In conclusion, hypokalemia is more likely to occur in females, in patients receiving intravenous VCZ, and in patients with the combined use of antibiotics. Hyponatremia is more likely to occur in patients older than 47years who have been using VCZ for a long time and have higher VCZ C0 values.

Enhancing the identification of voriconazole-associated hepatotoxicity by targeted metabolomics

Voriconazole-associated hepatotoxicity is a common condition that generally manifests as elevated liver enzymes and can lead to drug discontinuation. Careful monitoring of voriconazole-associated hepatotoxicity is needed but there are no specific plasma biomarkers for this condition. Metabolomics has emerged as a promising technique for investigating biomarkers associated with drug-induced toxicity. The aim of this study was to use targeted metabolomics to evaluate seven endogenous metabolites as potential biomarkers of voriconazole-associated hepatotoxicity. Patients undergoing therapeutic drug monitoring of voriconazole were classified into a hepatotoxicity group (18 patients) or a control group (153 patients). Plasma samples were analysed using ultra-high-performance liquid chromatography coupled to mass spectrometry. Metabolite concentrations in the two groups were compared. Areas under the receiver operating characteristic (AUROC) curves generated from logistic regressions were used to correlate the concentrations of these seven metabolites with voriconazole trough concentrations and conventional liver biochemistry tests. Glycocholate and α-ketoglutarate levels were significantly higher in the hepatotoxicity group compared with the control group (false discovery rate-corrected P < 0.001 and P = 0.024, respectively). The metabolites glycocholate (AUROC = 0.795) and α-ketoglutarate (AUROC = 0.696) outperformed voriconazole trough concentrations (AUROC = 0.555) and approached the performance of alkaline phosphatase (AUROC = 0.876) and total bilirubin (AUROC = 0.815). A panel of glycocholate combined with voriconazole trough concentrations (AUROC = 0.827) substantially improved the performance of voriconazole trough concentrations alone in predicting hepatotoxicity. In conclusion, the panel integrating glycocholate with voriconazole trough concentrations has great potential for identifying voriconazole-associated hepatotoxicity.

Voriconazole-induced visual abnormality based on drug interaction between voriconazole and esomeprazole: A case report.

We report a case of voriconazole-induced visual abnormality based on drug interaction of voriconazole and esomeprazole, therapeutic drug monitoring, and optimal therapy. An 81-year-old male developed visual abnormality after the blood concentration of voriconazole was up to 6.47 mg/L induced by coadministration with esomeprazole. Voriconazole is a substrate of multiple CYP450 isoenzymes including CYP2C19 (the major route), CYP3A4, and CYP2C9. Esomeprazole, a proton pump inhibitor (PPI), is also converted to inactive metabolites through CYP3A4 and CYP2C19-mediated metabolism, and is also a CYP2C19 inhibitor. The coadministration with esomeprazole inhibited the metabolism of voriconazole via CYP2C19 and promoted the elevation of voriconazole blood concentration beyond the minimum toxic level (5.5mg/L). According to the pharmacist's advice, the adverse effects of visual abnormalities in the patient disappeared after the clinician reduced voriconazole dosage by 50% when other medication schedules remained unchanged. Therefore, therapeutic drug monitoring of voriconazole should be considered in patients receiving PPIs, especially esomeprazole, in order to adjust the dosage in time and achieve optimal therapeutic response and minimal adverse reaction.

Therapeutic Drug Monitoring of Voriconazole in Patients with End-Stage Liver Disease.

This study aimed to identify the factors that influence voriconazole (VCZ) plasma concentrations and optimize the doses of VCZ in patients with end-stage liver disease (ESLD). Patients with ESLD who received a VCZ maintenance dose of 100 mg twice daily (group A, n = 57) or the VCZ maintenance dose of 50 mg twice daily (group B, n = 37), orally or intravenously, were enrolled in this study. Trough plasma concentrations (Cmin) of VCZ between 1 and 5 mg/L were considered within the therapeutic target range. The VCZ Cmin was determined in 94 patients with ESLD. The VCZ Cmin of patients in group A was remarkably higher than those in group B (4.85 ± 2.53 mg/L vs 2.75 ± 1.40 mg/L; P < 0.001). Compared with group A, fewer patients in group B had VCZ Cmin outside the therapeutic target (23/57 vs. 6/37, P = 0.021). Univariate and multivariate analyses suggested that both body weight and Model for End-Stage Liver Disease scores were closely associated with the VCZ Cmin in group B. These data indicate that dose optimization based on body weight and Model for End-Stage Liver Disease scores is required to strike an efficacy-safety balance during VCZ treatment in patients with ESLD.

Optimal timing for therapeutic drug monitoring of voriconazole to prevent adverse effects in Japanese patients.

The optimal timing for therapeutic drug monitoring (TDM) of voriconazole in Asians, who have higher rates of poor metabolisers than non-Asians, is unclear. This can cause unexpectedly high concentrations and delays in reaching steady-state levels. To determine the appropriate timing of TDM in Japanese patients receiving voriconazole. Trough levels (Cmin ) were measured on days 3-5 (recommended timing, RT) and days 6-14 (delayed timing, DT) after starting voriconazole in patients receiving an appropriate dosage. Considering bioavailability, Cmin was only compared in patients receiving oral voriconazole. A total of 289 and 186 patients were included in the safety and pharmacokinetic analyses, respectively. There was a significant difference in Cmin measured no later than and after day 5 (3.59 ± 2.12 [RT] vs. 4.77 ± 3.88 μg/mL [DT], p = .023), whereas no significant difference was observed on cutoff day 6 (3.91 ± 2.60 vs. 4.40 ± 3.94 μg/mL, p = .465), suggesting that Cmin close to the steady-state was achieved after day 5. DT causes a delay in achieving the therapeutic range. The hepatotoxicity rates were 21.5% and 36.8% in the RT and DT groups, respectively (p = .004); DT was an independent risk factor for hepatotoxicity. Although steady-state concentrations may not be achieved by day 5, early dose optimisation using RT can prevent hepatotoxicity in Japanese patients. TDM should be performed on days 3-5 to ensure safety. However, subsequent TDM may be necessary due to a possible further increase in Cmin .

Therapeutic drug monitoring of voriconazole and CYP2C19 phenotype for dose optimization in paediatric patients.

The objective of this study was to evaluate factors influencing voriconazole (VRC) plasma trough concentrations and provide research data for optimizing VRC dosing in Chinese paediatric patients. Medical records of inpatients were reviewed retrospectively. Multivariate linear regression analysis was used to identify the factors contributing to the variability of VRC plasma trough concentrations. A total of 250 VRC plasma trough concentrations from 131 paediatric patients were included in the analysis. The median VRC plasma trough concentration was 1.28mg·L-1 (range, 0.02 to 9.69mg·L-1). The target range was achieved in 51.6% of patients, while subtherapeutic and supratherapeutic concentrations were obtained in 40.4% and 8.0% of paediatric patients, respectively. The most commonly identified cytochrome P450 2C19 (CYP2C19) phenotype was intermediate metabolizers (IMs) (48.9%), followed by normal metabolizers (NMs) (40.5%) and poor metabolizers (PMs) (10.7%), but no ultrarapid metabolizers (UMs) were observed in our study. VRC plasma trough concentrations adjusted for dose (Cmin/D) were significantly lower in both NMs and IMs compared to PMs (PN-P < 0.001 and PI-P = 0.010, respectively). The dosage of VRC required to achieve the therapeutic range was related to age, with children aged < 6years needing a significantly higher oral dose of VRC. The oral and intravenous maintenance doses needed to reach the therapeutic range were significantly lower than the recommended maintenance dose (P < 0.001, P < 0.001). Factors such as CYP2C19 polymorphisms, the combination of omeprazole, levels of albumin and alanine aminotransferase, were found to affect VRC exposure and explained some of the variability. The VRC plasma trough concentration is significantly influenced by the CYP2C19 phenotype. The recommended maintenance dose for pediatric patients may not be appropriate for Chinese patients. To increase the probability of achieving the therapeutic range for VRC plasma trough concentration, the administration of VRC should consider the age of paediatric patients and the presence of CYP2C19 polymorphisms.

Insights into the selective imprinted polymer of voriconazole from host-guest interaction perspective

The incidence of fungal coinfections, such as Aspergillus spp., in patients with COVID-19 has been widely reported. Voriconazole is the first-line treatment for aspergillosis. A challenging sample preparation process is required to perform therapeutic drug monitoring of voriconazole. Recently, Molecularly Imprinted Polymers (MIP) have been shown to improve the separation selectivity for biological samples. Monomer selection in MIP is often performed by trial and error, without a design strategy. Therefore, this study aimed to construct a high-affinity MIP for voriconazole based on its interaction with functional monomers. All structures were optimized with B3LYP/6-311G++(d,p) and DFT-D3 dispersion correction method. Calculations of vacuum and solvated frequencies were carried out using a structure with maximum binding energy from molecular docking. The results showed that complex five was the most stable, exothermic, spontaneous, and enthalpy-driven among the complexes. In addition, there are nine intermolecular interactions and one moderate hydrogen bond in the QTAIM and NBO analysis, whereas hydrogen bonds, van der Waals interactions, and hydrophobic interactions were observed in the NCI-RDG analysis. The findings of this preliminary investigation showed that voriconazole possesses high stability when combined with functional monomers. It also provides information and assistance for further laboratory MIP synthesis.

Contribution of voriconazole N-oxide plasma concentration measurements to voriconazole therapeutic drug monitoring in patients with invasive fungal infection.

Voriconazole (VRC), a widely used triazole antifungal, exhibits significant inter- and intra-individual pharmacokinetic variability. The main metabolite voriconazole N-oxide (NOX) can provide information on the patient's drug metabolism capacity. Our objectives were to implement routine measurement of NOX concentrations and to describe the metabolic ratio (MR), and the contribution of the MR to VRC therapeutic drug monitoring (TDM) by proposing a suggested dosage-adjustment algorithm. Sixty-one patients treated with VRC were prospectively included in the study, and VRC and NOX levels were assayed by LC-MS/MS. A mixed logistic model on repeated measures was implemented to analyse risk factors for the patient's concentration to be outside the therapeutic range. Based on 225 measurements, the median and interquartile range were 2.4μg/ml (1.2; 4.2), 2.1μg/ml (1.5; 3.0) and 1.0 (0.6; 1.9) for VRC, NOX and the MR, respectively. VRC Cmin <2μg/ml were associated with a higher MR during the previous visit. MR values >1.15 and <0.48 were determined to be the best predictors for having a VRC Cmin lower than 2μg/ml and above 5.5μg/ml, respectively, at the next visit. Measurement of NOX resulted useful for TDM of patients treated with VRC. The MR using NOX informed interpretation and clinical decision-making and is very interesting for complex patients. VRC phenotyping based on the MR is now performed routinely in our institution. A dosing algorithm has been suggested from these results.

Therapeutic drug monitoring-guided treatment versus standard dosing of voriconazole for invasive aspergillosis in haematological patients: a multicentre, prospective, cluster randomised, crossover clinical trial

Voriconazole therapeutic drug monitoring (TDM) is recommended based on retrospective data and limited prospective studies. This study aimed to investigate whether TDM-guided voriconazole treatment is superior to standard treatment for invasive aspergillosis. A multicentre (n=10), prospective, cluster randomised, crossover clinical trial was performed in haematological patients aged ≥18 years treated with voriconazole. All patients received standard voriconazole dose at the start of treatment. Blood/serum/plasma was periodically collected after treatment initiation of voriconazole and repeated during treatment in both groups. The TDM group had measured voriconazole concentrations reported back, with dose adjustments made as appropriate, while the non-TDM group had voriconazole concentrations measured only after study completion. The composite primary endpoint included response to treatment and voriconazole treatment discontinuation due to an adverse drug reaction related to voriconazole within 28 days after treatment initiation. In total, 189 patients were enrolled in the study. For the composite primary endpoint, 74 patients were included in the non-TDM group and 68 patients in the TDM group. Here, no significant difference was found between both groups (P=0.678). However, more trough concentrations were found within the generally accepted range of 1-6 mg/L for the TDM group (74.0%) compared with the non-TDM group (64.0%) (P < 0.001). In this trial, TDM-guided dosing of voriconazole did not show improved treatment outcome compared with standard dosing. We believe that these findings should open up the discussion for an approach to voriconazole TDM that includes drug exposure, pathogen susceptibility and host defence. ClinicalTrials.gov registration no. NCT00893555.

HPLC-MS/MS Method Validation for Antifungal Agents in Human Serum in Clinical Application.

Therapeutic drug monitoring (TDM) of antifungal drugs is recommended. LC-MS/MS outperforms bioassay and high-performance liquid chromatography (HPLC) for TDM. In this study, we validated TDM for voriconazole, posaconazole, and itraconazole using HPLC-MS/MS with the multiple reaction monitoring (MRM) method. For the validation of LC-MS/MS for antifungal TDM, accuracy, precision, linearity, carryover, lower limit of quantitation (LLOQ), ion suppression, and sample stability tests were performed according to the guidelines of the United States Food and Drug Administration (FDA) and the Clinical and Laboratory Standards Institute (CLSI). The LC-MS/MS triazole method showed that all analytes had biases less than 8.9% and coefficients of variation (CV) less than 7.7%. The linearity was validated over the ranges of 0.20 to 5.86 mg/L for voriconazole, 0.12 to 4.96 mg/L for posaconazole, 0.09 to 1.85 mg/L for itraconazole, and 0.12 to 2.38 mg/L for OH-itraconazole. Ion suppression and carryover were negligible. The lower limits of quantitation (LLOQs) for voriconazole, posaconazole, itraconazole, and OH-itraconazole were 0.114 mg/L, 0.206 mg/L, 0.118 mg/L, and 0.065 mg/L, respectively. Voriconazole, posaconazole, itraconazole, and OH-itraconazole can be stored at 4℃ for 4 - 7 days, according to sample stability. Sample preparation took < 15 minutes per batch, and analytical run time was 5 minutes per sample. We developed and validated a simple, reliable, and quick LC-MS/MS method for triazole antifungal agents TDM suitable for routine hospital practice.

872. Voriconazole Therapeutic Drug Monitoring (TDM): How Common is Autoinduction?

Abstract Background Therapeutic drug monitor (TDM) guided optimized dosing of Voriconazole allows optimal drug exposure in the management of mold infection (MI). In addition to already known nuances in pharmacokinetics such as CYP2C19 genetic polymorphism and the role of drug interactions both necessitating TDM, case reports have suggested that auto-induction may occur after initially achieving a therapeutic level. We assessed whether the levels of Voriconazole can change over time and become subtherapeutic due to auto-induction. Methods We prospectively enrolled, adults ≥ 18 y.o of age, on Voriconazole for the treatment of MI at the University Of Alberta Hospital. After achieving an initial therapeutic margin, (1–5.5mg/l), we monitored Voriconazole levels twice a month, using high-performance liquid chromatography, until discontinuation or at 12 weeks of therapy. We calculated the incidence of Voriconazole sub-therapeutic concentrations (auto-induction) defined as drop of Voriconazole level below one, with previous concentrations between the therapeutic margins of 1–5.5 mg/L. Adjustment of Voriconazole dosing in case of auto-induction was at the discretion of the treating physician. The excess Voriconazole dose adjustment was calculated in patients where dosing was increased. Results Between January 2021 and April 2022, we enrolled 12 patients. Median age (IQR) was 62 (52–73), and 25 % were female. Patient characteristics are in table 1. Auto-induction was observed in 6/10 (60%) who completed 12 weeks follow up blood work. Median time to auto-induction was of 46 days (39–55). Voriconazole dosing was increased in 4/6 patients with auto-induction. Of the four patients with dose adjustment, the cumulative Voriconazole dose was 13% higher than expected, which correspond to 5,300 mg excess Voriconazole per patient to maintain therapeutic levels. Conclusion Auto-induction is common in patients treated with Voriconazole. Future studies are needed to assess if undetected auto-induction affects outcomes. Funding: AVIR Pharma. Disclosures Carlos Cervera, Associate Professor, Astra-Zeneca: Advisor/Consultant|AVIR Pharma: Grant/Research Support|AVIR Pharma: Honoraria|Lilly: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Merck: Honoraria|Sunovion: Advisor/Consultant|Takeda: Advisor/Consultant|Takeda: Honoraria|VerityPharma: Advisor/Consultant Dima Kabbani, MD, MSc, AVIR Pharma: Grant/Research Support|AVIR Pharma: Honoraria|GSK: Honoraria|Merck: Grant/Research Support.

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

To characterize trough concentrations (Cmin) of voriconazole and associated hepatotoxicity, and to determine predictors of hepatotoxicity and identify high-risk groups in critically ill patients. This was a nationwide, multi-centre, retrospective study. Cmin 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. Large interindividual variability was observed in initial voriconazole Cmin 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 Cmin was significantly associated with hepatotoxicity. The CART model showed that significant predictors of grade ≥2 hepatotoxicity were Cmin >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 Cmin >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%. Higher voriconazole Cmin, 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.

High-Performance Liquid Chromatography for Ultra-Simple Determination of Plasma Voriconazole Concentration.

Voriconazole is an antifungal drug used to treat invasive aspergillosis. Voriconazole exhibits nonlinear behavior and considerable individual variability in its pharmacokinetic profile. Invasive aspergillosis has a poor prognosis, and failure of treatment owing to low voriconazole blood levels is undesirable. Thus, therapeutic drug monitoring (TDM) of voriconazole is recommended. However, plasma voriconazole concentration is rarely measured in hospitals, and the TDM of voriconazole is not widely practiced in Japan. We aimed to develop an ultra-simple method to measure plasma voriconazole concentration. Ten microliters of plasma sample was extracted, and proteins were precipitated using methanol extraction. Voriconazole and ketoconazole (internal standard) were separated using high-performance liquid chromatography. A calibration curve was prepared, which was linear over plasma voriconazole concentrations of 0.125–12.5 µg/mL, with a coefficient of determination of 0.9999. The intra-day and inter-day validation coefficients were 0.9–2.2% and 1.3–6.1%, respectively. The assay accuracy was −4.2% to 1.6%, and recovery was >97.8%. Our ultra-simple, sensitive, and inexpensive high-performance liquid chromatography ultraviolet method to determine plasma voriconazole concentration will help improve the voriconazole TDM implementation rate and contribute to effective and safe voriconazole use.

Comparison of LC-MS3 and LC-MRM Method for Quantifying Voriconazole and Its Application in Therapeutic Drug Monitoring of Human Plasma.

The TDM of voriconazole which exhibits wide inter-individual variability is indispensable for treatment in clinic. In this study, a method that high-performance liquid chromatography tandem mass spectrometry cubed (HPLC-MS3) is first built and validated to quantify voriconazole in human plasma. The system is composed of Shimadzu Exion LCTM UPLC coupled with a Qtrap 5500 mass spectrometer. The separation of voriconazole is performed on a Poroshell 120 SB-C18 column at a flow rate of 0.8 mL/min remaining 7 min for each sample. The calibration curves are linear in the concentration range of 0.25–20 μg/mL. Intra-day and inter-day accuracies and precisions are within 8.0% at three concentrations, and the recoveries and matrix effect are all within accepted limits. In terms of stability, there is no significant degradation of voriconazole under various conditions. The HPLC-MS3 and HPLC-MRM (multiple reaction monitoring) methods are compared in 42 patients with Passing–Bablok regression and Bland–Altman plots, and the results show no significant difference between the two methods. However, HPLC-MS3 has a higher S/N (signal-to-noise ratio) and response than the MRM. Finally, the HPLC-MS3 assay is successfully applied to monitor the TDM (therapeutic drug monitoring) of voriconazole in human plasma, and this verifies that the dosing guidelines for voriconazole have been well implemented in the clinic and patients have received excellent treatment.