scholarly journals Exposure-Response Relationships for Isavuconazole in Patients with Invasive Aspergillosis and Other Filamentous Fungi

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
Amit V. Desai ◽  
Laura L. Kovanda ◽  
William W. Hope ◽  
David Andes ◽  
Johan W. Mouton ◽  
...  
Keyword(s):  
Steady State ◽  
Invasive Aspergillosis ◽  
Filamentous Fungi ◽  
Aspartate Aminotransferase ◽  
Drug Exposure ◽  
Fungal Infections ◽  
Plasma Concentrations ◽  
Water Soluble ◽  
Therapeutic Drug ◽  
Exposure Response

ABSTRACT Isavuconazole, the active moiety of the water-soluble prodrug isavuconazonium sulfate, is a triazole antifungal agent for the treatment of invasive fungal infections. The purpose of this analysis was to characterize the isavuconazole exposure-response relationship for measures of efficacy and safety in patients with invasive aspergillosis and infections by other filamentous fungi from the SECURE clinical trial. Two hundred thirty-one patients who received the clinical dosing regimen and had exposure parameters were included in the analysis. The primary drug exposure parameters included were predicted trough steady-state plasma concentrations, predicted trough concentrations after 7 and 14 days of drug administration, and area under the curve estimated at steady state (AUCss). The exposure parameters were analyzed against efficacy endpoints that included all-cause mortality through day 42 in the intent-to-treat (ITT) and modified ITT populations, data review committee (DRC)-adjudicated overall response at end of treatment (EOT), and DRC-adjudicated clinical response at EOT. The safety endpoints analyzed were elevated or abnormal alanine aminotransferase, increased aspartate aminotransferase, and a combination of the two. The endpoints were analyzed using logistic regression models. No statistically significant relationship (P > 0.05) was found between isavuconazole exposure and either efficacy or safety endpoints. The lack of association between exposure and efficacy indicates that the isavuconazole exposures achieved by clinical dosing were appropriate for treating the infecting organisms in the SECURE study and that increases in alanine or aspartate aminotransferase were not related to increase in exposures. Without a clear relationship, there is no current clinical evidence for recommending routine therapeutic drug monitoring for isavuconazole.

scholarly journals Posaconazole Exposure-Response Relationship: Evaluating the Utility of Therapeutic Drug Monitoring

2012 ◽  
Vol 56 (6) ◽  
pp. 2806-2813 ◽  
Author(s):  
Michael J. Dolton ◽  
John E. Ray ◽  
Deborah Marriott ◽  
Andrew J. McLachlan
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Fungal Infections ◽  
Gastrointestinal Disease ◽  
Plasma Concentrations ◽  
Response To Therapy ◽  
Common Finding ◽  
Therapeutic Drug ◽  
Response Relationship ◽  
Exposure Response

ABSTRACTPosaconazole has become an important part of the antifungal armamentarium in the prophylaxis and salvage treatment of invasive fungal infections (IFIs). Structurally related to itraconazole, posaconazole displays low oral bioavailability due to poor solubility, with significant drug interactions and gastrointestinal disease also contributing to the generally low posaconazole plasma concentrations observed in patients. While therapeutic drug monitoring (TDM) of plasma concentrations is widely accepted for other triazole antifungal agents such as voriconazole, the utility of TDM for posaconazole is controversial due to debate over the relationship between posaconazole exposure in plasma and clinical response to therapy. This review examines the available evidence for a relationship between plasma concentration and clinical efficacy for posaconazole, as well as evaluating the utility of TDM and providing provisional target concentrations for posaconazole therapy. Increasing evidence supports an exposure-response relationship for plasma posaconazole concentrations for prophylaxis and treatment of IFIs; a clear relationship has not been identified between posaconazole concentration and toxicity. Intracellular and intrapulmonary concentrations have been studied for posaconazole but have not been correlated to clinical outcomes. In view of the high mortality and cost associated with the treatment of IFIs, increasing evidence of an exposure-response relationship for posaconazole efficacy in the prevention and treatment of IFIs, and the common finding of low posaconazole concentrations in patients, TDM for posaconazole is likely to be of significant clinical utility. In patients with subtherapeutic posaconazole concentrations, increased dose frequency, administration with high-fat meals, and withdrawal of interacting medications from therapy are useful strategies to improve systemic absorption.

scholarly journals Software for Dosage Individualization of Voriconazole for Immunocompromised Patients

2013 ◽  
Vol 57 (4) ◽  
pp. 1888-1894 ◽  
Author(s):  
William W. Hope ◽  
Michael VanGuilder ◽  
J. Peter Donnelly ◽  
Nicole M. A. Blijlevens ◽  
Roger J. M. Brüggemann ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Fungal Infections ◽  
Plasma Concentrations ◽  
Therapeutic Drug ◽  
Cell Transplant ◽  
Multiple Model ◽  
Pharmacokinetic Variability ◽  
Hematopoietic Stem ◽  
Wide Range

ABSTRACTThe efficacy of voriconazole is potentially compromised by considerable pharmacokinetic variability. There are increasing insights into voriconazole concentrations that are safe and effective for treatment of invasive fungal infections. Therapeutic drug monitoring is increasingly advocated. Software to aid in the individualization of dosing would be an extremely useful clinical tool. We developed software to enable the individualization of voriconazole dosing to attain predefined serum concentration targets. The process of individualized voriconazole therapy was based on concepts of Bayesian stochastic adaptive control. Multiple-model dosage design with feedback control was used to calculate dosages that achieved desired concentration targets with maximum precision. The performance of the software program was assessed using the data from 10 recipients of an allogeneic hematopoietic stem cell transplant (HSCT) receiving intravenous (i.v.) voriconazole. The program was able to model the plasma concentrations with a high level of precision, despite the wide range of concentration trajectories and interindividual pharmacokinetic variability. The voriconazole concentrations predicted after the last dosages were largely concordant with those actually measured. Simulations provided an illustration of the way in which the software can be used to adjust dosages of patients falling outside desired concentration targets. This software appears to be an extremely useful tool to further optimize voriconazole therapy and aid in therapeutic drug monitoring. Further prospective studies are now required to define the utility of the controller in daily clinical practice.

A System for Individualized Dosing of Intravenous Aminophylline Using a Programmable Calculator

PEDIATRICS ◽  
1984 ◽  
Vol 73 (1) ◽  
pp. 64-67
Author(s):  
J. Chris Mitsuoka ◽  
Richard J. Fleck
Keyword(s):  
Steady State ◽  
Serum Sample ◽  
Drug Exposure ◽  
Plasma Concentrations ◽  
Dose Administration ◽  
Programmable Calculator ◽  
Concentration Determination ◽  
A Value ◽  
Individualized Dosing ◽  
History Of

A program that calculates a value of clearance for an individual patient prior to reaching steady state in the early stages of aminophylline therapy is presented. The program is written for the Texas Instruments TI-59 programmable calculator and may be used with or without the PC-100C printer. The program can provide clinically useful information concerning projected plasma concentrations prior to reaching steady state with an accurate history of the dose administration and serum concentration determination. If the patient has not received xanthene therapy prior to admission, only one serum sample is required. If there has been prior drug exposure, a second serum sample is required. An iterative technique, which would be impractical to use without calculator assistance, is employed to make these determinations.

scholarly journals Is It Time for Systematic Voriconazole Pharmacogenomic Investigation for Central Nervous System Aspergillosis?

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
François Danion ◽  
Vincent Jullien ◽  
Claire Rouzaud ◽  
Manal Abdel Fattah ◽  
Simona Lapusan ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Therapeutic Drug Monitoring ◽  
Invasive Aspergillosis ◽  
Drug Monitoring ◽  
Standard Treatment ◽  
Plasma Concentrations ◽  
Therapeutic Drug ◽  
Life Threatening ◽  
Trough Plasma

ABSTRACT Voriconazole is the standard treatment for invasive aspergillosis but requires therapeutic drug monitoring to optimize therapy. We report two cases of central nervous system aspergillosis treated with voriconazole. Because of low trough plasma concentrations, we identified gain-of-function mutations in CYP2C19 that were partially responsible for the therapeutic failure of voriconazole. We suggest that systematic voriconazole pharmacogenomic investigation of cerebral aspergillosis be performed to avoid effective therapy delay in this life-threatening disease.

scholarly journals A limited sampling schedule to estimate individual pharmacokinetics of pemetrexed in patients with varying renal functions

2019 ◽  
Vol 85 (1) ◽  
pp. 231-235
Author(s):  
Nikki de Rouw ◽  
Sabine Visser ◽  
Stijn L. W. Koolen ◽  
Joachim G. J. V. Aerts ◽  
Michel M. van den Heuvel ◽  
...  
Keyword(s):  
Mean Squared Error ◽  
Plasma Concentrations ◽  
Real Life ◽  
Accurate Estimation ◽  
Therapeutic Drug ◽  
Limited Sampling ◽  
Exposure Response ◽  
Squared Error ◽  
Precise Prediction ◽  
Sampling Schedule

Abstract Purpose Pemetrexed is a widely used cytostatic agent with an established exposure–response relationship. Although dosing is based on body surface area (BSA), large interindividual variability in pemetrexed plasma concentrations is observed. Therapeutic drug monitoring (TDM) can be a feasible strategy to reduce variability in specific cases leading to potentially optimized pemetrexed treatment. The aim of this study was to develop a limited sampling schedule (LSS) for the assessment of pemetrexed pharmacokinetics. Methods Based on two real-life datasets, several limited sampling designs were evaluated on predicting clearance, using NONMEM, based on mean prediction error (MPE %) and normalized root mean squared error (NRMSE %). The predefined criteria for an acceptable LSS were: a maximum of four sampling time points within 8 h with an MPE and NRMSE ≤ 20%. Results For an accurate estimation of clearance, only four samples in a convenient window of 8 h were required for accurate and precise prediction (MPE and NRMSE of 3.6% and 5.7% for dataset 1 and of 15.5% and 16.5% for dataset 2). A single sample at t = 24 h performed also within the criteria with MPE and NRMSE of 5.8% and 8.7% for dataset 1 and of 11.5% and 16.4% for dataset 2. Bias increased when patients had lower creatinine clearance. Conclusions We presented two limited sampling designs for estimation of pemetrexed pharmacokinetics. Either one can be used based on preference and feasibility.

scholarly journals Pharmacokinetics of Daptomycin in Critically Ill Pediatric Patients

2018 ◽  
Vol 62 (6) ◽  
Author(s):  
Charalampos Antachopoulos ◽  
Stavroula Ilia ◽  
Paschalis Kadiltzoglou ◽  
Eirini Baira ◽  
Aristides Dokoumetzidis ◽  
...  
Keyword(s):  
Critically Ill ◽  
Drug Exposure ◽  
Pediatric Patients ◽  
Plasma Concentrations ◽  
Therapeutic Drug ◽  
Burn Patients ◽  
Time Curve ◽  
Once Daily ◽  
Concentration Time ◽  
Optimal Drug

ABSTRACT The pharmacokinetics of daptomycin (10 mg/kg once daily) was studied in 4 critically ill pediatric patients aged 8 to 14 yrs. The area under the concentration-time curve from time zero to infinity (AUC 0–∞ ) of plasma concentrations on day 1 ranged between 123.8 to 663.9 μg · h/ml, with lower values observed in septic and burn patients; clearance ranged from 15.1 to 80.7 ml/h/kg. Higher-than-recommended doses of daptomycin may be needed in septic children to ensure optimal drug exposure. Interpatient variability may suggest a role for therapeutic drug monitoring.

scholarly journals Posaconazole Plasma Concentrations on Days Three to Five Predict Steady-State Levels

2016 ◽  
Vol 60 (9) ◽  
pp. 5595-5599 ◽  
Author(s):  
Jürgen Prattes ◽  
Wiebke Duettmann ◽  
Martin Hoenigl
Keyword(s):  
Steady State ◽  
Operating Characteristic ◽  
Hematological Malignancies ◽  
Fungal Infections ◽  
Plasma Concentrations ◽  
Area Under The Curve ◽  
Oral Solution ◽  
Curve Analysis ◽  
Roc Curve Analysis ◽  
Steady State Levels

ABSTRACTLow posaconazole plasma concentrations (PPCs) have been associated with breakthrough invasive fungal infections. We assessed the correlation between pre-steady-state PPCs (obtained between days 3 and 5) and PPCs obtained during steady state in 48 patients with underlying hematological malignancies receiving posaconazole oral-solution prophylaxis. Pre-steady-state PPCs correlated significantly with PPCs obtained at steady state (Spearmanr= 0.754;P< 0.001). Receiver operating characteristic (ROC) curve analysis of pre-steady-state PPCs revealed an area under the curve (AUC) of 0.884 (95% confidence interval [CI], 0.790 to 0.977) for predicting satisfactory PPCs at steady state.

scholarly journals Pharmacokinetics of Different Dosing Strategies of Oral Posaconazole in Patients with Compromised Gastrointestinal Function and Who Are at High Risk for Invasive Fungal Infection

2012 ◽  
Vol 56 (5) ◽  
pp. 2652-2658 ◽  
Author(s):  
Oliver A. Cornely ◽  
David Helfgott ◽  
Amelia Langston ◽  
Werner Heinz ◽  
Jörg-Janne Vehreschild ◽  
...  
Keyword(s):  
Steady State ◽  
High Risk ◽  
Fungal Infections ◽  
Plasma Concentrations ◽  
Nutritional Supplement ◽  
Gastrointestinal Function ◽  
Open Label ◽  
Dosing Regimens ◽  
Dosing Strategies ◽  
Poor Absorption

ABSTRACTThe aim of this study was to assess different dosing strategies that may result in increased posaconazole bioavailability in patients with compromised gastrointestinal function and at high risk for invasive fungal infections. Patients undergoing chemotherapy and at risk for compromised gastrointestinal function received open-label posaconazole at 200 mg three times daily (TID) on days 1 to 8. Patients were randomized to one of three open-label dosing regimens of posaconazole on days 9 to 15: 200 mg TID, 400 mg twice daily (BID), or 400 mg TID. The plasma concentrations of interest on days 8 and 15 were 500 and 700 ng/ml, respectively; day 2 plasma concentrations of 250 and 350 ng/ml were chosen as levels that might result in steady-state concentrations of >500 and >700 ng/ml, respectively. A total of 75 patients enrolled; 52/75 (69%) completed the study, and 49/75 were included in the pharmacokinetic analyses. Mean plasma concentrations were 230, 346, and 637 ng/ml on days 2, 3, and 8, respectively. The day 15 values were 660, 930, and 671 ng/ml for 200 mg TID, 400 mg BID, and 400 mg TID, respectively. In 12 patients with a day 8 posaconazole concentration of <250 ng/ml, an overall benefit of the higher two doses was not apparent, suggesting that a subset of patients has low steady-state plasma concentrations. A change in dosing regimen on day 9 did not lead to higher exposures in these “poor absorbers” on day 15. Poor absorption may be enhanced with a high-fat meal, a nutritional supplement, or acidification.

scholarly journals Model Based Identification of Linezolid Exposure–toxicity Thresholds in Hospitalized Patients

2021 ◽  
Vol 12 ◽  
Author(s):  
Jie Fang ◽  
Xiao-Shan Zhang ◽  
Chun-Hong Zhang ◽  
Zi-Ye Zhou ◽  
Lu Han ◽  
...  
Keyword(s):  
Steady State ◽  
Serum Albumin ◽  
White Cell Count ◽  
Plasma Concentrations ◽  
Regression Tree ◽  
Predictive Performance ◽  
Volume Of Distribution ◽  
Classification And Regression Tree ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic

Evidence supports linezolid therapeutic drug monitoring as the exposure–response relationship has been identified for toxicity among patients receiving linezolid, but the data to establish the upper limit are limited and the published toxicity thresholds range widely. The purpose of this study was to determine the linezolid exposure–toxicity thresholds to improve the safety of linezolid. This is a multicenter retrospective study of adult patients treated with linezolid from 2018 to 2019. The population pharmacokinetic model of linezolid was established based on 270 plasma concentrations in 152 patients, which showed creatinine clearance and white cell count are covariates affecting the clearance of linezolid, and serum albumin is the covariate affecting the volume of distribution. Classification and regression tree analysis was used to determine the linezolid exposure thresholds associated with an increased probability of toxicity. Among 141 patients included for toxicity analysis, the rate of occurring toxicity was significantly higher among patients with an AUC0-24, d1 ≥163 mg h/L, AUC0-24, d2 ≥207 mg h/L, AUC0-24, ss ≥210 mg h/L, and Cmin,d2 ≥6.9 mg/L, Cmin,ss ≥6.9 mg/L, while no threshold was discovered for Cmin, d1. Those exposure thresholds and duration of linezolid treatment were independently associated with linezolid-related toxicity in the logistic regression analyses. In addition, the predictive performance of the AUC0-24 and Cmin thresholds at day 2 and steady state were close. Considering that the AUC estimation is cumbersome, Cmin threshold at 48 h and steady state with a value of ≥6.9 mg/L is recommended to improve safety, especially for patients with renal insufficiency and patients with low serum albumin.

scholarly journals Model-Optimized Fluconazole Dose Selection for Critically Ill Patients Improves Early Pharmacodynamic Target Attainment without the Need for Therapeutic Drug Monitoring

2020 ◽  
Vol 65 (3) ◽  
Author(s):  
Indy Sandaradura ◽  
Jessica Wojciechowski ◽  
Deborah J. E. Marriott ◽  
Richard O. Day ◽  
Sophie Stocker ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Critically Ill ◽  
Drug Monitoring ◽  
Critically Ill Patients ◽  
Drug Exposure ◽  
Fungal Infections ◽  
Therapeutic Drug ◽  
Target Attainment ◽  
Dose Selection ◽  
Dose Individualization

ABSTRACT Fluconazole has been associated with higher mortality compared with the echinocandins in patients treated for invasive candida infections. Underexposure from current fluconazole dosing regimens may contribute to these worse outcomes, so alternative dosing strategies require study. The objective of this study was to evaluate fluconazole drug exposure in critically ill patients comparing a novel model-optimized dose selection method with established approaches over a standard 14-day (336-h) treatment course. Target attainment was evaluated in a representative population of 1,000 critically ill adult patients for (i) guideline dosing (800-mg loading and 400-mg maintenance dosing adjusted to renal function), (ii) guideline dosing followed by therapeutic drug monitoring (TDM)-guided dose adjustment, and (iii) model-optimized dose selection based on patient factors (without TDM). Assuming a MIC of 2 mg/liter, free fluconazole 24-h area under the curve (fAUC24) targets of ≥200 mg · h/liter and <800 mg · h/liter were used for assessment of target attainment. Guideline dosing resulted in underexposure in 21% of patients at 48 h and in 23% of patients at 336 h. The TDM-guided strategy did not influence 0- to 48-h target attainment due to inherent procedural delays but resulted in 37% of patients being underexposed at 336 h. Model-optimized dosing resulted in ≥98% of patients meeting efficacy targets throughout the treatment course, while resulting in less overexposure compared with guideline dosing (7% versus 14%) at 336 h. Model-optimized dose selection enables fluconazole dose individualization in critical illness from the outset of therapy and should enable reevaluation of the comparative effectiveness of this drug in patients with severe fungal infections.

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