Individualized, dynamic, and full-course vancomycin dosing prediction: a study on the customized dose model.

Purpose: The single-point trough-based therapeutic drug monitoring (TDM) and Bayesian forecasting approaches are still limited in individualized and dynamic vancomycin delivery. Until recently, there has not yet been enough focus on the direct integration of pharmacokinetic/pharmacodynamic (PK/PD) and TDM to construct a customized dose model (CDM) for vancomycin to achieve individualized, dynamic, and full-course dose prediction from empirical to follow-up treatment. This study sought to establish CDM for vancomycin, test its performance and superiority in clinical efficacy prediction, formulate a CDM-driven full-course dosage prediction strategy to overcome the above challenge, and predict the empirical vancomycin dosages for six Staphylococci populations and four strains in patients with various creatinine clearance rates (CLcr). Methods: The PK/PD and concentration models derived from our earlier research were used to establish CDM. The receiver operating characteristic (ROC) curve, with the area under ROC curve (AUCR) as the primary endpoint, for 21 retrospective cases was applied to test the performance and superiority of CDM in clinical efficacy prediction by comparison to the current frequently-used dose model (FDM). A model with an AUCR of at least 0.8 was considered acceptable. Based on the availability of TDM, the strategy of CDM-driven individualized, dynamic, and full-course dose prediction for vancomycin therapy was formulated. Based on the CDM, Monte Carlo simulation was used to predict the empirical vancomycin dosages for the target populations and bacteria. Results: Four CDMs and the strategy of CDM-driven individualized, dynamic, and full-course dose prediction for vancomycin therapy from empirical to follow-up treatment were constructed. Compared with FDM, CDM showed a greater AUCR value (0.807 vs. 0.688) in clinical efficacy prediction. The empirical vancomycin dosages for six Staphylococci populations and four strains in patients with various CLcr were predicted. Conclusion: CDM is a competitive individualized dose model. It compensates for the drawbacks of the existing TDM technology and Bayesian forecasting and offers a straightforward and useful supplemental approach for individualized and dynamic vancomycin delivery. Through mathematical modeling of the vancomycin dosage, this study achieved the goal of predicting doses individually, dynamically, and throughout, thus promoting "mathematical knowledge transfer and application" and also providing reference for quantitative and personalized research on similar drugs.

USP21-mediated G3BP1 stabilization accelerates proliferation and metastasis of esophageal squamous cell carcinoma via activating Wnt/ß-Catenin signaling.

Lacking effective therapeutic targets heavily restricts the improvement of clinical prognosis for patients diagnosed with esophageal squamous cell carcinoma (ESCC). Ubiquitin Specific Peptidase 21 (USP21) is dysregulated in plenty of human cancers, however, its potential function and relevant molecular mechanisms in ESCC malignant progression as well as its value in clinical translation remain largely unknown. Here, in vitro and in vivo experiments revealed that aberrant upregulation of USP21 accelerated the proliferation and metastasis of ESCC in a deubiquitinase-dependent manner. Mechanistically, we found that USP21 binds to, deubiquitinates, and stabilizes the G3BP Stress Granule Assembly Factor 1 (G3BP1) protein, which is required for USP21-mediated ESCC progression. Further molecular studies demonstrated that the USP21/G3BP1 axis played a tumor-promoting role in ESCC progression by activating the Wnt/ß-Catenin signaling pathway. Additionally, disulfiram (DSF), an inhibitor against USP21 deubiquitylation activity, markedly abolished the USP21-mediated stability of G3BP1 protein and significantly displayed an anti-tumor effect on USP21-driving ESCC progression. Finally, the regulatory axis of USP21/G3BP1 was demonstrated to be aberrantly activated in ESCC tumor tissues and closely associated with advanced clinical stages and unfavorable prognoses, which provides a promising therapeutic strategy targeting USP21/G3BP1 axis for ESCC patients.

Pharmacokinetic/Pharmacodynamic Target Attainment of Vancomycin, at Three Reported Infusion Modes, for Methicillin-Resistant Staphylococcus aureus (MRSA) Bloodstream Infections in Critically Ill Patients: Focus on Novel Infusion Mode.

Objective: The study aimed to evaluate and compare the pharmacokinetic/pharmacodynamic (PK/PD) exposure to vancomycin in the novel optimal two-step infusion (OTSI) vs. intermittent infusion (II) vs. continuous infusion (CI) mode, for MRSA bloodstream infections occurring in critical patients. Methods: With PK/PD modeling and Monte Carlo simulations, the PK/PD exposure of 15 OTSI, 13 II, and 6 CI regimens for vancomycin, at 1, 2, 3, 4, 5, and 6 g daily dose, was evaluated. Using the Monte Carlo simulations, the vancomycin population PK parameters derived from critical patients, the PD parameter for MRSA isolates [i.e., minimum inhibitory concentration (MIC)], and the dosing parameters of these regimens were integrated into a robust mdel of vancomycin PK/PD index, defined as a ratio of the daily area under the curve (AUC0-24) to MIC (i.e., AUC0-24/MIC), to estimate the probability of target attainment (PTA) of these regimens against MRSA isolates with an MIC of 0.5, 1, 2, 4, and 8 mg/L in patients with varying renal function. The PTA at an AUC0-24/MIC ratio of >400, 400-600, and >600 was estimated. A regimen with a PTA of ≥90% at an AUC0-24/MIC ratio of 400-600, which is supposed to maximize both efficacy and safety, was considered optimal. Results: At the same daily dose, almost only the OTSI regimens showed a PTA of ≥90% at an AUC0-24/MIC ratio of 400-600, and this profile seems evident especially in patients with creatinine clearance (CLcr) of ≥60 ml/min and for isolates with an MIC of ≤2 mg/L. However, for patients with CLcr of <60 ml/min and for isolates with an MIC of ≥4 mg/L, the II regimens often displayed a higher or even ≥90% PTA at an AUC0-24/MIC ratio of >400 and of >600. The CI regimens frequently afforded a reduced PTA at an AUC0-24/MIC ratio of >400 and of >600, regardless of CLcr and MIC. Conclusions: The data indicated that the OTSI regimens allowed preferred PK/PD exposure in terms of both efficacy and safety, and thus should be focused more on, especially in patients with CLcr of ≥60 ml/min and for isolates with an MIC of ≤2 mg/L.

Predicted Vancomycin Dosage Requirement in Patients With Hematological Malignancies and Dosage Dynamic Adjustment.

Purpose: The purpose of this study was 1) to predict the requisite vancomycin daily dose (D van ) used in the target patients suffering from both bacterial infection and hematological malignancies and 2) to construct a vancomycin-dose-graphical tool to assist clinicians to develop vancomycin dosing regimens and further 3) to establish a programming process for vancomycin dynamic dosage adjustment to help clinicians to adjust vancomycin dosing regimens according to physiological and pathogenic factors of the target patients. Methods: The D van model associated with microbial susceptibility, vancomycin pharmacokinetics, and dosing parameters was established, and the D van was estimated based on the established D van model and using Monte Carlo simulations. D van achieving 90% of probability of target attainment (PTA) for bacterial isolate or cumulative fractions of response (CFR) for the bacterial population at a ratio of daily area under the curve (AUC24) to the minimum inhibitory concentration (MIC) [i.e., AUC24/MIC] of 400-600 was considered sufficient to treat infection occurring in the target patients. On the basis of the predicted D van , the physiological states of patients, and the pathogenic variables of infection, a vancomycin-dose-graphical tool for the target patients and a programming process for vancomycin dynamic dosage adjustment were constructed. Results: This study predicted the requisite D van used in patients suffering from both bacterial infection and hematological malignancies and constructed a vancomycin-dose-graphical tool for the target patients, at different physiological states and pathogenic variables, to formulate vancomycin dosing regimens. Also, this study established and expounded the formulation process of vancomycin dosage dynamic adjustment according to fluctuant renal function of the target patients. Conclusion: With the tools, the required D van or vancomycin dosing regimens for the target patients, at different physiological states and pathogenic variables, can be readily known, whether or not vancomycin dynamic dosage adjustment is required.

Competence Mining of Vancomycin (VAN) in the Management of Infections Due to Bacterial Strains With High VAN Minimum Inhibitory Concentrations (MICs): A Novel Dosing Strategy Based on Pharmacokinetic/Pharmacodynamic Modeling.

The increasing emergence of bacterial strains with high VAN MICs (BS H - V AN- M ), such as Enterococcus faecalis, Enterococcus faecium, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus bovis, results in growing concern that VAN is not effective against these isolates. Due to the limited data on VAN against BS H-VAN-M and the application limits of drugs currently considered to be effective for BS H-VAN-M , exploration of "new usages for old drugs" is reasonable to improve and maximize the efficacy of existing antibiotics. This study aimed to construct a novel dosing strategy to mine the competence of VAN in the management of BS H-VAN-M infections. Herein, we optimized the traditional intermittent i.v. infusion (TIII) method to create an optimal two-step infusion (OTSI). With pharmacokinetic (PK)/pharmacodynamic (PD) modeling at the targeted ratio of the daily area under the concentration-time curve (AUC0 - 24) to the minimum inhibitory concentration (MIC) (AUC0 - 24/MIC) of 400, we used Monte Carlo simulations to evaluate the efficacy of 25 VAN regimens (including 15 OTSI regimens and 10 TIII regimens with daily doses of up to 6 g) to treat pneumonia, meningitis, sternal osteomyelitis, mastitis, pleuritis, bacteremia, and bacterial pericarditis resulting from isolates with MICs of ≤64 mg/L and to the current E. faecalis, E. faecium, S. aureus, S. epidermidis, and S. bovis populations with a pooled MIC distribution. Our data indicated that 4 g/day VAN, with an OTSI but not a TIII, for mastitis, pleuritis, bacteremia, and bacterial pericarditis due to isolates with MICs of ≤4 mg/L or to the current E. faecalis, S. aureus, S. epidermidis, and S. bovis populations achieved the desired PK/PD exposure at the AUC0 - 24/MIC target of 400. This study suggests the superiority and feasibility of OTSI relative to TIII for the competence mining of VAN against BS H-VAN-M from the perspective of PK/PD and provides a new resource for understanding how PK/PD modeling shapes the performance of VAN to meet the growing challenges of BS H-VAN-M infections.

Is Meropenem as a Monotherapy Truly Incompetent for Meropenem-Nonsusceptible Bacterial Strains? A Pharmacokinetic/Pharmacodynamic Modeling With Monte Carlo Simulation.

Infections due to meropenem-nonsusceptible bacterial strains (MNBSs) with meropenem minimum inhibitory concentrations (MICs) ≥ 16 mg/L have become an urgent problem. Currently, the optimal treatment strategy for these cases remains uncertain due to some limitations of currently available mono- and combination therapy regimens. Meropenem monotherapy using a high dose of 2 g every 8 h (q 8 h) and a 3-h traditional simple prolonged-infusion (TSPI) has proven to be helpful for the treatment of infections due to MNBSs with MICs of 4-8 mg/L but is limited for cases with higher MICs of ≥16 mg/L. This study demonstrated that optimized two-step-administration therapy (OTAT, i.e., a new administration model of i.v. bolus plus prolonged infusion) for meropenem, even in monotherapy, can resolve this problem and was thus an important approach of suppressing such highly resistant bacterial isolates. Herein, a pharmacokinetic (PK)/pharmacodynamic (PD) modeling with Monte Carlo simulation was performed to calculate the probabilities of target attainment (PTAs) and the cumulative fractions of response (CFRs) provided by dosage regimens and 39 OTAT regimens in five dosing models targeting eight highly resistant bacterial species with meropenem MICs ≥ 16 mg/L, including Acinetobacter baumannii, Acinetobacter spp., Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Stenotrophomonas maltophilia, were designed and evaluated. The data indicated that meropenem monotherapy administered at a high dose of 2 g q 8 h and as an OTAT achieved a PTA of ≥90% for isolates with an MIC of up to 128 mg/L and a CFR of ≥90% for all of the targeted pathogen populations when 50% f T > MIC (50% of the dosing interval during which free drug concentrations remain above the MIC) is chosen as the PD target, with Enterococcus faecalis being the sole exception. Even though 50% f T > 5 × MIC is chosen as the PD target, the aforementioned dosage regimen still reached a PTA of ≥90% for isolates with an MIC of up to 32 mg/L and a CFR of ≥90% for Acinetobacter spp., Pseudomonas aeruginosa, and Klebsiella pneumoniae populations. In conclusion, meropenem monotherapy displays potential competency for infections due to such highly resistant bacterial isolates provided that it is administered as a reasonable OTAT but not as the currently widely recommended TSPI.

Pharmacodynamic model for ß-lactam regimens used in surgical prophylaxis: model-based evaluation of standard dosing regimens.

Background Continual evolution of resistance among bacteria against methods of surgical prophylaxis may make currently used beta-lactam regimens inadequate. Objective To re-evaluate beta-lactam regimens in surgical prophylaxis. Setting A pharmacodynamic Monte Carlo simulation (MCS) model based on a number of patients in China. Methods Pharmacodynamic profiling using Monte Carlo simulation up to 4 hours postinfusion was conducted for standard-dose, short-term (0.5 h) and prolonged (2 to 4 h) infusions of ampicillin, cefazolin, cefotaxime, cefoxitin, cefuroxime, ertapenem, and piperacillin/tazobactam in adult patients with normal renal function. Microbiological data were incorporated. Cumulative fraction of response (CFR) was determined for each regimen against populations of S. aureus, coagulase-negative staphylococci and E. coli. The optimal CFR was defined as ≥ 90% response. Main Outcome Measure Cumulative fractions of response of pharmacodynamic target attainment. Results During the first 2 hours postinfusion, piperacillin/tazobactam 3.375 g exhibited consistently optimal cumulative fractions against S. aureus, CoNS and E. coli. Ampicillin 2 g (2 h) also displayed optimal CFRs for S. aureus and E. coli but not for coagulase-negative staphylococci. Cefoxitin 2 g didnot achieve any optimal CFRs, even via 2-h prolonged infusion (maximum 72.8% CFR for S. aureus and 64.5% CFR for E. coli). Cefazolin 2 g (4 h) and cefuroxime 1.5 g (4 h) provided desired CFRs across 4 h postinfusion for S. aureus but provided poor CFRs for coagulase-negative staphylococci and E. coli. Only ertapenem 1 g for E. coli and S. aureus and cefotaxime 1 g for E. coli consistently yielded ≥ 90% CFRs for 4 hour postinfusion. Conclusions Certain dosing regimens may warrant adjustment for improved prevention efficiency and enhanced empirical antibiotic regimens for surgical prophylaxis.