Risk Factors for Teicoplanin-Associated Acute Kidney Injury in Patients with Hematological Malignancies: Focusing on Concomitant Use of Tazobactam/Piperacillin.

Patients with hematological malignancies (HM) often receive tazobactam/piperacillin (TAZ/PIPC) and glycopeptide antibiotics for febrile neutropenia. The effect of concomitant use of TAZ/PIPC on risk of teicoplanin (TEIC)-associated acute kidney injury (AKI) remains unclear. We investigated the impact of concomitant TAZ/PIPC use on TEIC-associated AKI in HM patients and identified the risk factors. In this retrospective, single-center, observational cohort study, 203 patients received TEIC, 176 of whom satisfied the selection criteria and were divided into TEIC cohort (no TAZ/PIPC; n = 118) and TEIC + TAZ/PIPC cohort (n = 58). AKI was defined as serum creatinine increase ≥0.3 mg/dL within 48 h or ≥50% from baseline. Incidence of AKI in TEIC cohort before and after propensity score matching was 9.3 and 5.9%, respectively, and that in TEIC + TAZ/PIPC cohort was 10.3 and 11.8%. AKI incidence and risk were not significantly different between two cohorts before (p = 0.829; odds ratio (OR) 1.122, 95% confidence interval (CI) 0.393-3.202) and after matching (p = 0.244; OR 2.133, 95% CI 0.503-9.043). Logistic regression analysis with factors clinically or mechanistically potentially related to TEIC-associated AKI, including concomitant TAZ/PIPC use, as independent variables identified baseline hemoglobin level as the only significant risk factor for TEIC-associated AKI (p = 0.011; OR 0.484, 95% CI 0.276-0.848). In HM patients treated with TEIC, concomitant TAZ/PIPC use did not increase AKI risk whereas lower hemoglobin levels had higher risk for TEIC-associated AKI development, suggesting the necessity to monitor serum creatinine when using TEIC in patients with anemia.

Usefulness of Belimumab in Adult Patients With Systemic Lupus Erythematosus Evaluated Using Single Indexes: A Meta-Analysis and Systematic Review.

Background: Belimumab is the first antibody drug approved for systemic lupus erythematosus (SLE), and is a fully human monoclonal antibody that inhibits soluble B lymphocyte stimulator protein. In clinical trials, a composite index was used to assess efficacy of belimumab. However, clinical guidelines on SLE treatment currently use single efficacy indexes. Objective: The main objective of this study was to perform a meta-analysis to evaluate the efficacy of belimumab utilizing single indexes used in routine clinical practice, rather than the composite efficacy index used in clinical trials during the development phase. As a secondary endpoint, safety was also evaluated. Methods: Several databases were searched to identify reports published up to December 1, 2021 on randomized controlled trials examining the efficacy of belimumab in adult patients with SLE. From the clinical trial data, efficacy was evaluated using single indexes including the SLE Disease Activity Index (SLEDAI), British Isles Lupus Assessment Group Index, and Physician Global Assessment. Safety was also assessed. Data were synthesized and analyzed using Review Manager 5.4. This study protocol was registered in the UMIN Clinical Trials Registry (Registration number: UMIN000052846). Results: The search identified 12 reports that met the inclusion criteria. Five reports were included in efficacy evaluation and 9 in safety evaluation. The primary endpoint was SLEDAI. Significantly more belimumab-treated patients achieved a ≥4-point reduction in SLEDAI (relative risk 1.28; 95% confidence interval, 1.16-1.40; P < 0.00001) compared with placebo. Other efficacy endpoints were also improved significantly in the belimumab group. No difference in safety was found between belimumab and placebo. Conclusions: The present meta-analysis evaluating clinical trial data using various single indexes recommended by clinical guidelines for SLE verifies that addition of belimumab to standard of care is efficacious for moderate-to-severe SLE.

[Comparison of Preparation Efficiency and Therapeutic Safety between Brand-Name and Generic Products of Pemetrexed].

At Oita University Hospital, we switched our usage of pemetrexed(PEM)from brand-name to generic drugs. We conducted a comparative study of the preparation efficiency and therapeutic safety with the brand-name product and examined the economic effect thereof. The incidence of adverse drug reactions was investigated retrospectively using electronic medical records for patients who received PEM brand-name and generic drugs at our hospital between April 2021 and December 2022. The preparation time per mg was significantly shorter in the generic group at 0.17(0.08-0.38)seconds compared to 0.34(0.15-0.94)seconds for the brand-name group(p<0.01). Regarding the safety comparison, none of the 13 eligible patients developed new hematologic or non-hematologic toxicities of Grade 2 or higher after switching to the generic product. The switch to generics had an economic impact of 7,369,278 yen during the study period. The results suggest that switching from brand-name to generic products is reasonable from the perspectives of therapeutic safety and economic benefits, as well as the expected improvement in preparation efficiency.

Evaluation of effects of indoxyl sulfate and parathyroid hormone on CYP3A activity considering the influence of CYP3A5 gene polymorphisms.

AIMS: Indoxyl sulfate and parathyroid hormone (PTH), which accumulate in chronic kidney disease (CKD), have been reported to reduce cytochrome P450(CYP)3A activity. Homozygotes of the CYP3A5*3 allele have reduced CYP3A5 activity compared to carriers of at least one CYP3A5*1 allele. 4ß-Hydroxycholesterol (4ß-OHC) has been established as an endogenous substrate reflecting CYP3A activity. 4ß-OHC is produced through hydroxylation by CYP3A4 and CYP3A5 and by autoxidation of cholesterol, whereas 4α-hydroxycholesterol (4α-OHC) is produced solely by autoxidation of cholesterol. This study focused on CKD patients and evaluated the effects of plasma indoxyl sulfate and intact-PTH concentrations on plasma 4ß-OHC concentration, 4ß-OHC/total cholesterol ratio and 4ß-OHC-4α-OHC, with consideration of the influence of CYP3A5 polymorphism. METHODS: Sixty-three CKD patients were analysed and divided into CYP3A5 carrier group (n = 26) and non-carrier group (n = 37). RESULTS: Plasma indoxyl sulfate significantly correlated inversely with 4ß-OHC concentration and with 4ß-OHC-4α-OHC in both the CYP3A5*1 carrier group (r = -0.42, P = .034; r = -0.39, P = .050, respectively) and the non-carrier group (r = -0.45, P = .0054; r = -0.39, P = .019, respectively). However, multiple regression analysis did not identify plasma indoxyl sulfate concentration as a significant independent factor associated with any of the CYP3A activity indices. There was no significant correlation between plasma intact-PTH concentration and any of the CYP3A activity indices. CONCLUSIONS: The present results suggest that plasma indoxyl sulfate and intact-PTH concentrations do not have clinically significant effects on CYP3A activity in patients with CKD.

Positive correlation between organic anion transporter 1B function indicated by plasma concentration of coproporphyrin-I and blood concentration of cyclosporin A in real-world patients.

AIMS: Cyclosporin A (CyA) has potent inhibitory activity on organic anion transporting polypeptide 1B (OATP1B), causing drug-drug interactions with its substrate drugs. 3-carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF), a uraemic toxin, has also been suggested to inhibit OATP1B activity. Recent study has identified coproporphyrin-I (CP-I) as a specific endogenous substrate for OATP1B, which is useful to indicate OATP1B activity. We investigated the relationship of CP-I with CyA and CMPF concentrations in patients taking CyA. METHODS: In total, 121 blood samples from 74 patients who took CyA and underwent routine therapeutic drug monitoring were divided into trough and peak samples. RESULTS: CyA and CP-I concentrations were significantly higher in peak samples than in trough samples. A positive correlation between CP-I and CyA concentrations was found in all samples and in trough and peak samples, while no correlation was observed between CP-I and CMPF concentrations. Multiple regression analysis identified CyA and C-reactive protein concentrations as independent factors affecting CP-I concentration, with blood CyA concentration having markedly greater contribution to plasma CP-I concentration. CONCLUSION: The present study suggests that CyA inhibits OATP1B activity in a concentration-dependent manner in clinical setting, and that dose adjustment of OATP1B substrate drugs coadministered with CyA according to plasma CMPF concentration may not be necessary.

Comparison of Incidence of Hyponatremia between Linezolid and Vancomycin by Propensity Score Matching Analysis.

Several cases of severe hyponatremia induced by linezolid (LZD) were reported. However, severe infections could also cause hyponatremia by increasing vasopressin secretion. To prove that hyponatremia is associated with LZD rather than infection, we compared the incidence and risk of developing hyponatremia between patients receiving LZD and those receiving vancomycin (VCM). A retrospective, single-center, observational cohort study was conducted in patients aged 18 years or older who received intravenous LZD or VCM for 7 d or longer. Hyponatremia was defined as serum sodium level lower than 134 mEq/L and more than 5% decrease from baseline after treatment initiation. The incidence and risk of developing hyponatremia were analyzed between LZD and VCM groups using chi-square test. Four hundred and fifty patients who satisfied the selection criteria were divided into LZD (n = 97) and VCM groups (n = 353). Significant differences in patient characteristics between LZD and VCM groups were observed before propensity score matching, but no significant differences were found after matching. LZD group showed a significantly higher incidence and risk of developing hyponatremia compared to VCM group both before (LZD: 16.5%, VCM: 5.4%; p < 0.001, odds ratio 3.472 [95% confidence interval (CI) 1.711-7.048]) and after (LZD: 17.8%, VCM: 5.5%; p = 0.020, odds ratio 3.738 [95% CI 1.157-12.076]) propensity score matching. In conclusion, propensity score analyses suggest that the risk of hyponatremia associated with LZD is approximately 3.7-fold higher than that associated with VCM, regardless of patient background.

UHPLC-MS/MS method for simultaneous quantification of doripenem, meropenem, ciprofloxacin, levofloxacin, pazufloxacin, linezolid, and tedizolid in filtrate during continuous renal replacement therapy.

BACKGROUND: Since severe infections frequently cause acute kidney injury (AKI), continuous renal replacement therapy (CRRT) is often initiated for regulation of inflammatory mediators and renal support. Thus, it is necessary to decide the antibiotic dosage considering the CRRT clearance in addition to residual renal function. Some of the hemofilters used in CRRT are known to adsorb antibiotics, and clearance of antibiotics may differ depending on the adsorptive characteristics of hemofilters. Although assay systems for blood and CRRT filtrate concentrations are required, no method for measuring antibiotics concentrations in filtrate has been reported. We developed a UHPLC-MS/MS method for simultaneous quantification of antibiotics commonly used in ICU, comprising carbapenems [doripenem (DRPM) and meropenem (MEPM)], quinolones [ciprofloxacin (CPFX), levofloxacin (LVFX) and pazufloxacin (PZFX)] and anti-MRSA agents [linezolid (LZD), and tedizolid (TZD)] in CRRT filtrate samples. METHODS: Filtrate samples were pretreated by protein precipitation. The analytes were separated with an ACQUITY UHPLC CSH C18 column under a gradient mobile phase consisting of water and acetonitrile containing 0.1% formic acid and 2 mM ammonium formate. RESULTS: The method showed good linearity over wide ranges. Within-batch and batch-to-batch accuracy and precision for each drug fulfilled the criteria of the US Food and Drug Administration guidance. The recovery rate was more than 87.20%. Matrix effect ranged from 99.57% to 115.60%. Recovery rate and matrix effect did not differ remarkably between quality control samples at different concentrations. CONCLUSION: This is the first report of a simultaneous quantification method of multiple antibiotics in filtrate of CRRT circuit.

Sensitive UHPLC-MS/MS quantification method for 4ß- and 4α-hydroxycholesterol in plasma for accurate CYP3A phenotyping.

4ß-Hydroxycholesterol (4ß-OHC) is formed by Cytochrome P450 (CYP)3A and has drawn attention as an endogenous phenotyping probe for CYP3A activity. However, 4ß-OHC is also increased by cholesterol autooxidation occurring in vitro due to dysregulated storage and in vivo by oxidative stress or inflammation, independent of CYP3A activity. 4α-hydroxycholesterol (4α-OHC), a stereoisomer of 4ß-OHC, is also formed via autooxidation of cholesterol, not by CYP3A, and thus may have clinical potential in reflecting the state of cholesterol autooxidation. In this study, we establish a sensitive method for simultaneous quantification of 4ß-OHC and 4α-OHC in human plasma using ultra-high performance liquid chromatography coupled to tandem mass spectrometry. Plasma samples were prepared by saponification, two-step liquid-liquid extraction, and derivatization using picolinic acid. Intense [M+H]+ signals for 4ß-OHC and 4α-OHC di-picolinyl esters were monitored using electrospray ionization. The assay fulfilled the requirements of the US Food and Drug Administration guidance for bioanalytical method validation, with a lower limit of quantification of 0.5 ng/ml for both 4ß-OHC and 4α-OHC. Apparent recovery rates from human plasma ranged from 88.2% to 101.5% for 4ß-OHC, and 91.8% to 114.9% for 4α-OHC. Additionally, matrix effects varied between 86.2% and 117.6% for 4ß-OHC and between 89.5% and 116.9% for 4α-OHC. Plasma 4ß-OHC and 4α-OHC concentrations in healthy volunteers, stage 3-5 chronic kidney disease (CKD) patients, and stage 5D CKD patients as measured by the validated assay were within the calibration ranges in all samples. We propose this novel quantification method may contribute to accurate evaluation of in vivo CYP3A activity.

High-Sensitivity and High-Throughput Quantification of Everolimus in Human Whole Blood Using Ultrahigh-Performance Liquid Chromatography Coupled With Tandem Mass Spectrometry.

BACKGROUND: Rigorous dose adjustment by therapeutic drug monitoring (TDM) is recommended when everolimus (EVR) is administered for immunosuppression. In this study, the authors developed a highly sensitive ultrahigh-performance liquid chromatography coupled with the tandem mass spectrometry (UHPLC-MS/MS) method for measuring EVR concentrations in whole blood using a high-throughput solid-phase extraction method for sample pretreatment. Furthermore, the blood EVR concentrations in routine TDM samples from patients who underwent renal transplantation measured using the established UHPLC-MS/MS method were compared with those measured using the latex agglutination turbidimetric immunoassay (LTIA). METHODS: Blood samples were pretreated by solid-phase extraction using a 96-well HLB µElution plate. The clinical application of the newly developed method was evaluated using 87 blood samples from 19 patients who underwent kidney transplant. RESULTS: The calibration curve showed good linearity over a wide range of 0.1-50 ng/mL, with relative error ≤15% obtained from the back calculation of calibrators, and ≤20% for the lower limit of quantification. Within-batch and batch-to-batch accuracies and precisions fulfilled the acceptance criteria of the US Food and Drug Administration guidelines for bioanalytical method validation. The extraction recovery rates were good (≥65.2%), and almost no matrix effects were found in any of the quality control samples. Blood EVR concentrations measured by UHPLC-MS/MS were positively correlated with those measured by LTIA. A Bland-Altman plot indicated that the UHPLC-MS/MS method yielded better measurements than the LTIA method, regardless of the concentration. CONCLUSIONS: Therefore, the authors succeeded in developing a novel high-sensitivity and high-throughput method for measuring blood EVR concentration by UHPLC-MS/MS using a µElution plate for sample pretreatment.

Development of a Sensitive and High-Throughput Assay for Simultaneous Quantification of 5 Tyrosine Kinase Inhibitors and 2 Active Metabolites in Human Plasma Using Ultra-high Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry.

BACKGROUND: Breakpoint cluster region-Abelson (BCR-ABL) tyrosine kinase inhibitors (TKIs) demonstrate improved therapeutic efficacy in chronic myeloid leukemia (CML). However, drug-drug interactions, nonadherence, and host-related factors may influence plasma concentrations. Therefore, therapeutic drug monitoring may be necessary for patients presenting inadequate treatment responses or adverse events. Herein, the authors aimed to develop a more sensitive and high-throughput method than those previously reported to simultaneously quantify 5 TKIs (imatinib, nilotinib, dasatinib, bosutinib, and ponatinib) and 2 active metabolites (N-desmethyl imatinib and N-desmethyl ponatinib) using ultra-performance liquid chromatography coupled with tandem mass spectrometry. METHODS: Plasma samples were prepared according to a solid-phase extraction protocol using an Oasis MCX µElution plate. The assay fulfilled the requirements of the US Food and Drug Administration for assay validation, with a lower limit of quantification of 0.2 ng/mL for dasatinib, 0.3 ng/mL for N-desmethyl ponatinib, 0.5 ng/mL for N-desmethyl imatinib, bosutinib, and ponatinib, and 2.5 ng/mL for imatinib and nilotinib. RESULTS: Within-batch and batch-to-batch precision at the lower limit of quantification and quality control levels were within 14.3% and 10.9%, respectively. Within-batch and batch-to-batch accuracies ranged from 15.5% to 13.0% and 5.70% to 7.03%, respectively. A positive electrospray ionization mode was used with a run time of 6.0 minutes. The assay applicability was verified by the successful measurement of 78 clinical samples from patients undergoing CML therapy. CONCLUSIONS: The method allows assessment of trough concentrations of TKIs and active metabolites in patients with CML, and hence can be used to assess blood samples in routine clinical settings.

Association of Vancomycin Trough Concentration and Clearance With Febrile Neutropenia in Pediatric Patients.

BACKGROUND: Febrile neutropenia promotes renal drug excretion. Adult and pediatric patients with febrile neutropenia exhibit a lower vancomycin concentration/dose (relative to bodyweight) ratio than those with other infections. In pediatric patients, renal function relative to bodyweight varies depending on age, and vancomycin clearance is age dependent. This study aimed to analyze the effects of febrile neutropenia on the pharmacokinetics of vancomycin in age-stratified pediatric patients. METHODS: This retrospective, single-center, observational cohort study analyzed 112 hospitalized pediatric patients who met the selection criteria and intravenously received vancomycin at the Department of Pediatrics of the Oita University Hospital between April 2011 and October 2019. RESULTS: The febrile neutropenia (n = 46) cohort exhibited a significantly higher estimated glomerular filtration rate than the nonfebrile neutropenia (n = 66) cohort. Compared with those in the nonfebrile neutropenia cohort, the daily vancomycin dose relative to bodyweight and vancomycin clearance were significantly higher, and the vancomycin trough concentration and vancomycin concentration/dose ratio were significantly lower in the febrile neutropenia cohort. In the age groups of 1-6 and 7-12 years, compared with those in the nonfebrile neutropenia cohort, the vancomycin concentration/dose ratio was significantly lower, and vancomycin clearance was significantly higher in the febrile neutropenia cohort. Univariate and multivariate analyses identified febrile neutropenia as the independent factor influencing vancomycin concentration/dose ratio and clearance only in pediatric patients aged 1-6 years. CONCLUSIONS: Increased initial dosage and therapeutic drug monitoring-guided dose optimization are critical for the therapeutic efficacy of vancomycin in pediatric patients with febrile neutropenia, especially in those aged 1-6 years.

Impact of Inflammation on Intra-individual Variation in Trough Voriconazole Concentration in Patients with Hematological Malignancies.

The pharmacokinetics of voriconazole shows large intra-individual and inter-individual variability and is affected by various factors. Recently, inflammation has been focused as a significant factor affecting the variability. This study aimed to compare the influence of C-reactive protein (CRP) and other clinical laboratory parameters on intra-individual variability in trough voriconazole concentration and examine the impact of inflammation in patients with hematological malignancies. We conducted a retrospective, single-center, observational cohort study. Forty-two patients with hematological malignancy who received oral voriconazole for prophylaxis against deep mycosis and underwent multiple measurements of trough plasma voriconazole concentration were recruited. Quantitative changes in pharmacological and clinical laboratory parameters (Δ) were calculated as the difference between the current and preceding measurements. Voriconazole concentration/maintenance dose per weight (C/D) was found to correlate positively with CRP level (n = 202, rs = 0.314, p < 0.001). Furthermore, ΔC/D correlated positively with ΔCRP level (n = 160, rs = 0.442, p < 0.001), and ΔCRP showed the highest correlation coefficient among the laboratory parameters. Univariate and multivariate analyses identified ΔCRP (p < 0.001) and Δgamma-glutamyl transpeptidase (γGTP) (p = 0.019) as independent factors associated with ΔC/D. Partial R2 were 0.315 for ΔCRP and 0.024 for ΔγGTP, suggesting markedly greater contribution of ΔCRP to ΔC/D. In conclusion, since clinical laboratory parameters other than CRP had little influence on trough plasma voriconazole concentration, therapeutic drug monitoring and dose adjustment considering fluctuation in CRP level would be important for proper use of voriconazole in patients with hematological malignancies.

Highly sensitive simultaneous quantification of indoxyl sulfate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid in human plasma using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry.

Indoxyl sulfate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid are uremic toxins that accumulate in renal failure and have been reported to decrease the activities of the drug-metabolizing enzyme cytochrome P450 3A and the drug transporter organic anion transporting polypeptides 1B, respectively. In this study, we established and validated an assay for simultaneous quantification of indoxyl sulfate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid in human plasma. The samples were pretreated by solid-phase extraction, and measured by ultra-high-performance liquid chromatography-tandem mass spectrometry. The validation results for this assay were within the acceptable limits recommended by the US Food and Drug Administration, with a lower limit of quantitation of 0.05 µg/mL for both indoxyl sulfate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid. Recovery rates of indoxyl sulfate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid corrected by internal standard were 100.7-101.9 and 100.2-101.3%, respectively. Matrix effects of indoxyl sulfate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid corrected by internal standard were 101.1-105.5 and 97.0-103.8%, respectively. The validated assay was used to analyze indoxyl sulfate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid concentrations in the plasma samples of healthy volunteers and patients with chronic kidney disease. All the measured plasma indoxyl sulfate and 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid concentrations were within the calibration ranges. This novel method may contribute to predicting the activities of drug-metabolizing enzymes and drug transporters in individual patients.

Exacerbation of cancer pain after administering immune checkpoint inhibitor in a patient taking opioids: A case report.

WHAT IS KNOWN AND OBJECTIVE: Clinical cases of attenuation of opioid analgesic effect by administration of immune checkpoint inhibitors has not been reported. We present a case of head and neck cancer under pain management with opioids, in which cancer pain was exacerbated after administration of nivolumab. CASE SUMMARY: A male patient with head and neck cancer was hospitalized for the second-line treatment of nivolumab. He had complained of head and neck pain after admission, but the pain was especially worse after nivolumab administration. The dose of opioids was eventually increased by approximately 320% (morphine equivalent dose) compared to before administering nivolumab. WHAT IS NEW AND CONCLUSION: When administering immune checkpoint inhibitors such as nivolumab in clinical practice, the possibility of attenuation of opioid analgesic effect should be considered.

Development of a High-Throughput Quantification Method for Pazopanib Using Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry and Its Clinical Application in Patients With Soft Tissue Tumors.

BACKGROUND: Pazopanib is widely used to treat renal cell carcinomas and soft tissue tumors in Japan. Pazopanib has significant therapeutic efficacy but it is associated with frequent severe adverse effects. Therapeutic drug monitoring (TDM) may help to prevent adverse effects. A more convenient and rapid pazopanib assay is desirable for the application of TDM in clinical settings. In this study, the authors developed a high-throughput method for quantifying pazopanib in human plasma using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). METHODS: After a simple solid-phase extraction step using a 96-well plate, pazopanib was analyzed by UHPLC-MS/MS in the positive electrospray ionization mode. RESULTS: The novel method fulfilled the requirements of the US Food and Drug Administration and the European Medicines Agency guidelines for assay validation, and the lower limit of quantification was 0.5 mcg/mL. The calibration curves were linear over the concentration range of 0.5-100 mcg/mL. The average recovery rate was 102.0% ± 3.9% (mean ± SD). The precision was below 5.0%, and the accuracy was within 12.0% for all quality control levels. Matrix effect varied between 90.9% and 97.1%. This assay was successfully applied to TDM of pazopanib trough concentrations in 3 patients treated with the drug for soft tissue tumors. CONCLUSIONS: The authors succeeded in developing a novel high-throughput UHPLC-MS/MS method for quantifying pazopanib in human plasma. This method can be applied to TDM of patients receiving pazopanib in clinical settings.

A Broad Range High-Throughput Assay for Lenvatinib Using Ultra-High Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry With Clinical Application in Patients With Hepatocellular Carcinoma.

BACKGROUND: Lenvatinib is increasingly being selected as the first-line treatment for unresectable hepatocellular carcinoma (HCC) based on the results of the REFLECT trial. However, early discontinuation of lenvatinib because of adverse effects is a frequent occurrence. Hence, lenvatinib is a difficult drug for use in the clinical setting. One of the causes is that the dose of lenvatinib is mainly determined by body weight alone, despite high interindividual variability. To overcome this problem, a dosing regimen of lenvatinib based on a population pharmacokinetic (PPK) model for HCC patients is proposed. The aim of this study was to develop a high-throughput quantification method for lenvatinib using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) that can be applied to a PPK analysis of HCC patients in the future. METHODS: After a simple solid-phase extraction step using a 96-well plate, lenvatinib was analyzed by UHPLC-MS/MS in a positive electrospray ionization mode. RESULTS: The novel method fulfilled the requirements of the US Food and Drug Administration guidance on bioanalytical method validation. The calibration curve was linear over the 0.2-1000 ng/mL concentration range. The average recovery rate was 98.63 ± 4.55% (mean ± SD). The precision was below 6.05%, and the accuracy was within 12.96% for all quality control levels. The matrix effect varied between 103.33% and 134.61%. This assay was successfully applied to the measurement of plasma concentrations in 6 HCC patients receiving lenvatinib. CONCLUSIONS: A novel high-throughput UHPLC-MS/MS assay for quantification of lenvatinib in human plasma was successfully developed. This method can be applied to PPK analysis for patients receiving lenvatinib in the clinical setting.

Pharmacokinetic and Adsorptive Analyses of Administration of Oral Voriconazole Suspension via Enteral Feeding Tube in Intensive Care Unit Patients.

For intensive care unit (ICU) patients, injectable voriconazole (VRCZ) is difficult to use because the patients often develop acute kidney injury. Since many ICU patients have consciousness disturbance, oral ingestion of tablet formulation is also difficult, and administration of a suspension via enteral feeding tube is required when using VRCZ. In this study, we investigated the in vitro adsorption property of oral VRCZ to feeding tube and performed pharmacokinetic analysis of VRCZ prepared by powdering and simple suspension for ICU patients. VRCZ was tube-administered to five ICU patients at a loading dose of 300 mg and plasma VRCZ concentrations before and at 1, 2, 4, 8, 12 h after the first dose were measured using HPLC. Pharmacokinetic parameters were calculated by non-compartmental model analysis. The recovery rate of VRCZ after infusion of the suspension through feeding tube was 89.8 ± 8.3%, but the cumulative rates after the first and second re-infusion were 102.7 ± 20.7 and 99.3 ± 10.3%, respectively, suggesting almost no residual drug in the tube after re-infusion. Metabolic phenotype was extensive metabolizer (EM) in two patients and intermediate metabolizer (IM) in three patients. The values of total clearance (CLtot/F) calculated by moment analysis were 0.51 and 0.55 L/h/kg in two EM patients, and 0.09, 0.29 and 0.31 L/h/kg in three IM patients. The CLtot/F was apparently lower in IM patients compared to EM. In conclusion, powdered and suspended VRCZ administered via enteral feeding tube showed pharmacokinetics depending on CYP2C19 gene polymorphism, similar to that observed in usual oral administration.

A retrospective test for a possible relationship between linezolid-induced thrombocytopenia and hyponatraemia.

WHAT IS KNOWN AND OBJECTIVE: Thrombocytopenia is one of the typical adverse events caused by linezolid (LZD). Recently, some cases of severe hyponatraemia occurring while receiving LZD have been reported. This study investigated a possible relationship between LZD-induced hyponatraemia and thrombocytopenia and identified the risk factors for hyponatraemia and/or thrombocytopenia. METHODS: In this retrospective, single-centre, observational cohort study, 63 hospitalized patients aged over 18 years who received intravenous injection of LZD for more than seven consecutive days in Oita University Hospital between April 2015 and March 2018 were analysed. RESULTS: Thrombocytopenia occurred in 25 (39.7%) patients and hyponatraemia in 11 (17.5%) patients. Seven of 11 patients with hyponatraemia had concurrent thrombocytopenia. Although both serum sodium level and platelet count declined in most patients who developed hyponatraemia, no significant association between thrombocytopenia and hyponatraemia was found. Creatinine clearance level (Ccr) was significantly lower not only in the thrombocytopenia (vs no-thrombocytopenia) but also in the hyponatraemia group (vs no-hyponatraemia group). Univariate and multivariate logistic regression analyses identified different risk factors for thrombocytopenia and/or hyponatraemia (thrombocytopenia: Ccr and administration period; hyponatraemia: serum albumin; thrombocytopenia and hyponatraemia: administration period and serum albumin). WHAT IS NEW AND CONCLUSION: In conclusion, this study found no significant relationship between LZD-induced thrombocytopenia and hyponatraemia and identified some possible risk factors associated with onset of the two adverse events. These require further validation.

Sensitive, wide-range and high-throughput quantification of cyclosporine in whole blood using ultra-performance liquid chromatography coupled to tandem mass spectrometry and comparison with an antibody-conjugated magnetic immunoassay.

Because either trough or peak concentration at 2 h after administration is measured in routine therapeutic drug monitoring for cyclosporine A (CyA), a quantification method with a wide-range calibration curve capable of simultaneously measuring both concentrations is required. We developed a sensitive, wide-range and high-throughput quantification method for CyA in whole blood using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and compared patients' blood CyA levels measured by UPLC-MS/MS and antibody-conjugated magnetic immunoassay (ACMIA). Whole blood samples were prepared by solid-phase extraction using Oasis HLB µElution plate. The UPLC-MS/MS assay showed excellent linearity over a wide calibration range of 5-2500 ng/mL. Within-batch accuracy and precision as well as batch-to-batch accuracy and precision fulfilled the criteria of US Food and Drug Administration guidelines. The blood CyA concentrations measured by the UPLC-MS/MS assay correlated strongly with those measured by ACMIA. A Bland-Altman plot showed a fixed error between CyA concentrations measured by the two methods, and the concentrations measured by the UPLC-MS/MS method were consistently lower than those measured by ACMIA. We have succeeded to develop a sensitive, wide-range and high-throughput quantification method for CyA in whole blood using UPLC-MS/MS.

[Comparison of Treatment Safety Between Brand-Name Product and Biosimilar of Trastuzumab].

At the Oita University Hospital, we switched from using the original biological product of trastuzumab(original product) to a biosimilar product, and verified the appropriateness of the switch by investigating the occurrence of adverse events. We compared the safety of the original and biosimilar products from January 2019 to September 2020. Of 14 cases studied, there were 6 in the original product group, 6 in the switched group, and 2 in the biosimilar group. In 3 patients in the switched group, infusion reaction was observed during administration of the original product, and was appropriately managed at that time. After switching to the biosimilar product, it was possible to administer the drug safely even when the infusion time was shortened. The results of this study showed that no adverse events were observed after switching from the original to the biosimilar product. This finding suggests that switching products is appropriate, not only from an economic point of view but also from the perspective of treatment safety.