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Boyer J, Hoenigl M, Kriegl L. Therapeutic drug monitoring of antifungal therapies: do we really need it and what are the best practices? Expert Rev Clin Pharmacol 2024; 17:309-321. [PMID: 38379525 DOI: 10.1080/17512433.2024.2317293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 02/07/2024] [Indexed: 02/22/2024]
Abstract
INTRODUCTION Despite advancements, invasive fungal infections (IFI) still carry high mortality rates, often exceeding 30%. The challenges in diagnosis, coupled with limited effective antifungal options, make managing IFIs complex. Antifungal drugs are essential for IFI management, but their efficacy can be diminished by drug-drug interactions and pharmacokinetic variability. Therapeutic Drug Monitoring (TDM), especially in the context of triazole use, has emerged as a valuable strategy to optimize antifungal therapy. AREAS COVERED This review provides current evidence regarding the potential benefits of TDM in IFI management. It discusses how TDM can enhance treatment response, safety, and address altered pharmacokinetics in specific patient populations. EXPERT OPINION TDM plays a crucial role in achieving optimal therapeutic outcomes in IFI management, particularly for certain antifungal agents. Preclinical studies consistently show a link between therapeutic drug levels and antifungal efficacy. However, clinical research in mycology faces challenges due to patient heterogeneity and the diversity of fungal infections. TDM's potential advantages in guiding Echinocandin therapy for critically ill patients warrant further investigation. Additionally, for drugs like Posaconazole, assessing whether serum levels or alternative markers like saliva offer the best measure of efficacy is an intriguing question.
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Affiliation(s)
- Johannes Boyer
- Division of Infectious Diseases, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Martin Hoenigl
- Division of Infectious Diseases, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- BioTechMed, Graz, Austria
- Translational Mycology Working Group, ECMM Excellence Center for Clinical Mycology, Medical University of Graz, Graz, Austria
| | - Lisa Kriegl
- Division of Infectious Diseases, Department of Internal Medicine, Medical University of Graz, Graz, Austria
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2
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Horton MV, Eix EF, Johnson CJ, Dean MEB, Andes BD, Wartman KM, Nett JE. Impact of micafungin on Candida auris β-glucan masking and neutrophil interactions. J Infect Dis 2024:jiae043. [PMID: 38330449 DOI: 10.1093/infdis/jiae043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 01/16/2024] [Accepted: 01/21/2024] [Indexed: 02/10/2024] Open
Abstract
Invasive fungal pathogen Candida auris has become a public health threat causing outbreaks of high mortality infections. Drug resistance often limits treatment options. For Candida albicans, subinhibitory concentrations of echinocandins unmask immunostimulatory β-glucan, augmenting immunity. Here we analyze the impact of echinocandin treatment of C. auris on β-glucan exposure and human neutrophil interactions. We show subinhibitory concentrations lead to minimal glucan unmasking and only subtle influences on neutrophil functions for the isolates belonging to circulating clades. The data suggest that echinocandin treatment will not largely alter phagocytic responses. Glucan masking pathways appear to differ between C. auris and C. albicans.
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Affiliation(s)
- Mark V Horton
- Department of Medicine, University of Wisconsin-Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, USA
| | - Emily F Eix
- Department of Medicine, University of Wisconsin-Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, USA
| | - Chad J Johnson
- Department of Medicine, University of Wisconsin-Madison, WI, USA
| | - Megan E B Dean
- Department of Medicine, University of Wisconsin-Madison, WI, USA
| | - Brody D Andes
- Department of Medicine, University of Wisconsin-Madison, WI, USA
| | - Kayla M Wartman
- Department of Medicine, University of Wisconsin-Madison, WI, USA
| | - Jeniel E Nett
- Department of Medicine, University of Wisconsin-Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, WI, USA
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3
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Andes DR, Nett JE. Analysis of Candida Antifungal Resistance Using Animal Infection Models. Methods Mol Biol 2023; 2658:225-238. [PMID: 37024706 DOI: 10.1007/978-1-0716-3155-3_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Candida frequently produces three general disease states, including mucosal candidiasis, disseminated candidiasis, and biofilm infection (which can be present with either of the other disease states). Antifungal drug resistance is intrinsic to biofilm growth and has emerged in other disease states. Mechanistic studies have uncovered the genetic pathways governing resistance to a number of antifungal agents. However, analyzing the clinical relevance of distinct mechanisms is fundamental for broadening our knowledge of antifungal drug resistance and for delineating the potential impact of targeting these pathways medically. Also, as drug-resistant strains and biofilms represent important nosocomial problems, preclinical animal models to assess the activity of novel antifungals are of great interest. Here we describe two rodent models that mimic the most common biofilm device and disseminated candidiasis states in patients. The model systems incorporate the anatomical site, immune components, and antifungal exposures relevant for the study of antifungal resistance. The models can be used to analyze mutant strains, assess the extent of drug resistance, examine biofilm formation, test new antimicrobials, and help determine drug exposures that may be linked with clinical failure.
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4
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Jauregizar N, Quindós G, Gil-Alonso S, Suárez E, Sevillano E, Eraso E. Postantifungal Effect of Antifungal Drugs against Candida: What Do We Know and How Can We Apply This Knowledge in the Clinical Setting? J Fungi (Basel) 2022; 8:jof8070727. [PMID: 35887482 PMCID: PMC9317160 DOI: 10.3390/jof8070727] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/29/2022] [Accepted: 07/06/2022] [Indexed: 02/07/2023] Open
Abstract
The study of the pharmacological properties of an antifungal agent integrates the drug pharmacokinetics, the fungal growth inhibition, the fungicidal effect and the postantifungal activity, laying the basis to guide optimal dosing regimen selection. The current manuscript reviews concepts regarding the postantifungal effect (PAFE) of the main classes of drugs used to treat Candida infections or candidiasis. The existence of PAFE and its magnitude are highly dependent on both the fungal species and the class of the antifungal agent. Therefore, the aim of this article was to compile the information described in the literature concerning the PAFE of polyenes, azoles and echinocandins against the Candida species of medical interest. In addition, the mechanisms involved in these phenomena, methods of study, and finally, the clinical applicability of these studies relating to the design of dosing regimens were reviewed and discussed. Additionally, different factors that could determine the variability in the PAFE were described. Most PAFE studies were conducted in vitro, and a scarcity of PAFE studies in animal models was observed. It can be stated that the echinocandins cause the most prolonged PAFE, followed by polyenes and azoles. In the case of the triazoles, it is worth noting the inconsistency found between in vitro and in vivo studies.
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Affiliation(s)
- Nerea Jauregizar
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Bilbao, Spain;
- Correspondence:
| | - Guillermo Quindós
- Department of Immunology, Microbiology and Parasitology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Bilbao, Spain; (G.Q.); (S.G.-A.); (E.S.); (E.E.)
| | - Sandra Gil-Alonso
- Department of Immunology, Microbiology and Parasitology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Bilbao, Spain; (G.Q.); (S.G.-A.); (E.S.); (E.E.)
| | - Elena Suárez
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Bilbao, Spain;
| | - Elena Sevillano
- Department of Immunology, Microbiology and Parasitology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Bilbao, Spain; (G.Q.); (S.G.-A.); (E.S.); (E.E.)
| | - Elena Eraso
- Department of Immunology, Microbiology and Parasitology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Bilbao, Spain; (G.Q.); (S.G.-A.); (E.S.); (E.E.)
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5
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Kovanda LL, Sass G, Martinez M, Clemons KV, Nazik H, Kitt TM, Wiederhold N, Hope WW, Stevens DA. Efficacy and Associated Drug Exposures of Isavuconazole and Fluconazole in an Experimental Model of Coccidioidomycosis. Antimicrob Agents Chemother 2021; 65:e02344-20. [PMID: 33782009 PMCID: PMC8316117 DOI: 10.1128/aac.02344-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 03/14/2021] [Indexed: 12/19/2022] Open
Abstract
Coccidioides spp. are important pathogens in regions where they are endemic, and new treatment options are needed. Here, isavuconazonium sulfate (ISAVUSULF) and fluconazole (FLU) were evaluated in experimental disseminated coccidioidomycosis to characterize drug exposures associated with efficacy. Broth macrodilution was performed on Coccidioides isolates to measure minimal effective concentrations (MEC) and minimal fungicidal concentrations (MFC). Mice were inoculated with Coccidioides posadasii (Silveira strain). Treatment started 4 days postinoculation. In model 1, mice were treated for 19 days, followed by 30 days of off-therapy observation, measuring survival through day 49 and residual fungal burden. Treatments included ISAVUSULF (prodrug; 186, 279, or 372 mg/kg twice daily), FLU (20 or 100 mg/kg once daily), and no treatment. Model 2 included 7-day treatment with ISAVUSULF (prodrug; 74.4, 111.6, or 148.8 mg/kg twice daily), FLU (20 or 100 mg/kg once daily), and no treatment. Serial plasma and tissues samples were obtained for pharmacokinetics (PK) and fungal burden measurement, respectively. Fifty percent minimal effective concentration (MEC50) values were 0.39 mg/liter (isavuconazole [ISAV]) and 12.5 mg/liter (FLU). Treatment with ISAVUSULF186 or with either FLU dose resulted in higher survival compared to that in the untreated group. Treatment with ISAVUSULF186 or ISAVUSULF279 twice daily or FLU100 reduced fungal burden in all organs (model 1). In model 2, a >1 log10 CFU/organ reduction was demonstrated, with ISAV area under the concentration-time curve (AUC) values achieved with 111.6 mg/kg twice daily (56.8 mg · h/liter) in the spleen and liver. FLU AUC values of 100 and 500 mg·h/liter for 20 and 100 mg/kg doses, respectively, resulted in a >1 log10 CFU/organ mean reduction in all organs. ISAVUSULF and FLU improved survival and reduced fungal burden. Increasing plasma drug exposures resulted in decreases in fungal burden.
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Affiliation(s)
- Laura L Kovanda
- Astellas Pharma Global Development, Inc., Northbrook, Illinois, USA
| | - Gabriele Sass
- California Institute for Medical Research, San Jose, California, USA
| | - Marife Martinez
- California Institute for Medical Research, San Jose, California, USA
| | - Karl V Clemons
- California Institute for Medical Research, San Jose, California, USA
| | - Hasan Nazik
- California Institute for Medical Research, San Jose, California, USA
| | - Therese M Kitt
- Astellas Pharma Global Development, Inc., Northbrook, Illinois, USA
| | - Nathan Wiederhold
- University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - William W Hope
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
- Royal Liverpool and Broadgreen University Hospital Trust, Liverpool Health Partners, Liverpool, United Kingdom
| | - David A Stevens
- California Institute for Medical Research, San Jose, California, USA
- Stanford University School of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford, California, USA
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6
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Beredaki MI, Georgiou PC, Siopi M, Kanioura L, Arendrup MC, Mouton JW, Meletiadis J. Voriconazole efficacy against Candida glabrata and Candida krusei: preclinical data using a validated in vitro pharmacokinetic/pharmacodynamic model. J Antimicrob Chemother 2021; 75:140-148. [PMID: 31665417 DOI: 10.1093/jac/dkz425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 09/05/2019] [Accepted: 09/11/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Voriconazole exhibits in vitro activity against Candida glabrata and Candida krusei (EUCAST/CLSI epidemiological cut-off values 1/0.25 and 1/0.5 mg/L, respectively). Yet, EUCAST found insufficient evidence to set breakpoints for these species. We explored voriconazole pharmacodynamics (PD) in an in vitro dynamic model simulating human pharmacokinetics (PK). METHODS Four C. glabrata and three C. krusei isolates (voriconazole EUCAST and CLSI MICs of 0.03-2 mg/L) were tested in the PK/PD model simulating voriconazole exposures (t½ ∼6 h q12h dosing for 3 days). PK/PD breakpoints were determined calculating the PTA for exposure indices fAUC0-24/MIC associated with half-maximal activity (EI50) using Monte Carlo simulation analysis. RESULTS Fungal load increased from 3.60±0.35 to 8.41±0.24 log10 cfu/mL in the drug-free control, with a maximum effect of ∼1 log10 kill of C. glabrata and C. krusei isolates with MICs of 0.06 and 0.25 mg/L, respectively, at high drug exposures. The 72 h log10 cfu/mL change versus fAUC0-24/MIC relationship followed a sigmoid curve for C. glabrata (R2=0.85-0.87) and C. krusei (R2=0.56-0.76) with EI50 of 49 (32-76) and 52 (33-78) fAUC/MIC for EUCAST and 55 (31-96) and 80 (42-152) fAUC/MIC for CLSI, respectively. The PTAs for C. glabrata and C. krusei isolates with EUCAST/CLSI MICs ≤0.125/≤0.06 mg/L were >95%. Isolates with EUCAST/CLSI MICs of 0.25-1/0.125-0.5 would require trough levels 1-4 mg/L; isolates with higher MICs would not attain the corresponding PK/PD targets without reaching toxicity. CONCLUSIONS The in vitro PK/PD breakpoints for C. glabrata and C. krusei for EUCAST (0.125 mg/L) and CLSI (0.06 mg/L) bisected the WT populations. Trough levels of >4 mg/L, which are not clinically feasible, are necessary for efficacy against WT isolates.
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Affiliation(s)
- Maria-Ioanna Beredaki
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiota-Christina Georgiou
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Siopi
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Lamprini Kanioura
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Maiken Cavling Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Joseph Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
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7
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The Role of New Posaconazole Formulations in the Treatment of Candida albicans Infections: Data from an In Vitro Pharmacokinetic-Pharmacodynamic Model. Antimicrob Agents Chemother 2021; 65:AAC.01292-20. [PMID: 33468486 DOI: 10.1128/aac.01292-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 12/28/2020] [Indexed: 12/12/2022] Open
Abstract
Posaconazole is more active than fluconazole against Candida albicans in vitro and is approved for the treatment of oropharyngeal candidiasis but not for that of invasive candidiasis (IC). Here, we explored the efficacy of posaconazole against C. albicans in an in vitro pharmacokinetic/pharmacodynamic (PK/PD) model of IC and determined the probability of pharmacodynamic target attainment for the oral solution and intravenous (i.v.)/tablet formulations. Three clinical C. albicans isolates (posaconazole MICs, 0.008 to 0.25 mg/liter) were studied in the in vitro PK/PD dilution model simulating steady-state posaconazole PK. The in vitro exposure-effect relationship, area under the 24-h free drug concentration curve (fAUC0-24)/MIC, was described and compared with in vivo outcome in animals with IC. PK/PD susceptibility breakpoints and trough levels required for optimal treatment were determined for EUCAST and CLSI 24-h/48-h (CLSI24h/CLSI48h) methods using the fAUC0-24/MIC associated with half-maximal activity (EI50) and Monte Carlo simulation analysis for oral solution (400 mg every 12 hours [q12h]) and i.v./tablet formulations (300 mg q24h). The in vitro mean (95% confidence interval [CI]) EI50 was 330 (183 to 597) fAUC0-24/MIC for CLSI24h and 169 (92 to 310) for EUCAST/CLSI48h methods, which are close to the near-stasis in vivo effect. The probability of target attainment for EI50 was estimated; for the wild-type isolates (MIC ≤ 0.06 mg/liter), it was low for the oral solution and higher than 95% for the i.v./tablet formulations for the EUCAST/CLSI48h methods but not for the CLSI 24-h method. Non-wild-type isolates with EUCAST/CLSI48h MICs of 0.125 and 0.25 mg/liter would require trough levels of >1.2 and >2.4 mg/liter, respectively. Posaconazole i.v./tablet formulations may have a role in the therapy of invasive infections by wild-type C. albicans isolates, provided that a steady state is reached quickly. A PK/PD susceptibility breakpoint at the epidemiological cutoff (ECV/ECOFF) of 0.06 mg/liter was determined.
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8
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Rayner CR, Smith PF, Andes D, Andrews K, Derendorf H, Friberg LE, Hanna D, Lepak A, Mills E, Polasek TM, Roberts JA, Schuck V, Shelton MJ, Wesche D, Rowland‐Yeo K. Model-Informed Drug Development for Anti-Infectives: State of the Art and Future. Clin Pharmacol Ther 2021; 109:867-891. [PMID: 33555032 PMCID: PMC8014105 DOI: 10.1002/cpt.2198] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/05/2021] [Indexed: 12/13/2022]
Abstract
Model-informed drug development (MIDD) has a long and rich history in infectious diseases. This review describes foundational principles of translational anti-infective pharmacology, including choice of appropriate measures of exposure and pharmacodynamic (PD) measures, patient subpopulations, and drug-drug interactions. Examples are presented for state-of-the-art, empiric, mechanistic, interdisciplinary, and real-world evidence MIDD applications in the development of antibacterials (review of minimum inhibitory concentration-based models, mechanism-based pharmacokinetic/PD (PK/PD) models, PK/PD models of resistance, and immune response), antifungals, antivirals, drugs for the treatment of global health infectious diseases, and medical countermeasures. The degree of adoption of MIDD practices across the infectious diseases field is also summarized. The future application of MIDD in infectious diseases will progress along two planes; "depth" and "breadth" of MIDD methods. "MIDD depth" refers to deeper incorporation of the specific pathogen biology and intrinsic and acquired-resistance mechanisms; host factors, such as immunologic response and infection site, to enable deeper interrogation of pharmacological impact on pathogen clearance; clinical outcome and emergence of resistance from a pathogen; and patient and population perspective. In particular, improved early assessment of the emergence of resistance potential will become a greater focus in MIDD, as this is poorly mitigated by current development approaches. "MIDD breadth" refers to greater adoption of model-centered approaches to anti-infective development. Specifically, this means how various MIDD approaches and translational tools can be integrated or connected in a systematic way that supports decision making by key stakeholders (sponsors, regulators, and payers) across the entire development pathway.
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Affiliation(s)
- Craig R. Rayner
- CertaraPrincetonNew JerseyUSA
- Monash Institute of Pharmaceutical SciencesMonash UniversityMelbourneVictoriaAustralia
| | | | - David Andes
- University of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Kayla Andrews
- Bill & Melinda Gates Medical Research InstituteCambridgeMassachusettsUSA
| | | | | | - Debra Hanna
- Bill & Melinda Gates FoundationSeattleWashingtonUSA
| | - Alex Lepak
- University of Wisconsin‐MadisonMadisonWisconsinUSA
| | | | - Thomas M. Polasek
- CertaraPrincetonNew JerseyUSA
- Centre for Medicines Use and SafetyMonash UniversityMelbourneVictoriaAustralia
- Department of Clinical PharmacologyRoyal Adelaide HospitalAdelaideSouth AustraliaAustralia
| | - Jason A. Roberts
- Faculty of MedicineUniversity of Queensland Centre for Clinical ResearchThe University of QueenslandBrisbaneQueenslandAustralia
- Departments of Pharmacy and Intensive Care MedicineRoyal Brisbane and Women’s HospitalBrisbaneQueenslandAustralia
- Division of Anaesthesiology Critical Care Emergency and Pain MedicineNîmes University HospitalUniversity of MontpellierMontpellierFrance
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9
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Optimization of Fluconazole Dosing for the Prevention and Treatment of Invasive Candidiasis Based on the Pharmacokinetics of Fluconazole in Critically Ill Patients. Antimicrob Agents Chemother 2021; 65:AAC.01554-20. [PMID: 33361296 DOI: 10.1128/aac.01554-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 12/15/2020] [Indexed: 12/31/2022] Open
Abstract
The efficacy of fluconazole is related to the area under the plasma concentration-time curve (AUC) over the MIC of the microorganism. Physiological changes in critically ill patients may affect the exposure of fluconazole, and therefore dosing adjustments might be needed. The aim of this study was to evaluate variability in fluconazole drug concentration in intensive care unit (ICU) patients and to develop a pharmacokinetic model to support personalized fluconazole dosing. A prospective observational pharmacokinetic study was performed in critically ill patients receiving fluconazole either as prophylaxis or as treatment. The association between fluconazole exposure and patient variables was studied. Pharmacokinetic modeling was performed with a nonparametric adaptive grid (NPAG) algorithm using R package Pmetrics. Data from 33 patients were available for pharmacokinetic analysis. Patients on dialysis and solid organ transplant patients had a significantly lower exposure to fluconazole. The population was best described with a one-compartment model, where the mean volume of distribution was 51.52 liters (standard deviation [SD], 19.81) and the mean clearance was 0.767 liters/h (SD, 0.46). Creatinine clearance was tested as a potential covariate in the model, but was not included in the final population model. A significant positive correlation was found between the fluconazole exposure (AUC) and the trough concentration (C min). Substantial variability in fluconazole plasma concentrations in critically ill adults was observed, where the majority of patients were underexposed. Fluconazole C min therapeutic drug monitoring (TDM)-guided dosing can be used to optimize therapy in critically ill patients. (This study has been registered at ClinicalTrials.gov under identifier NCT02491151.).
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10
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Lamoth F, Lewis RE, Kontoyiannis DP. Role and Interpretation of Antifungal Susceptibility Testing for the Management of Invasive Fungal Infections. J Fungi (Basel) 2020; 7:jof7010017. [PMID: 33396870 PMCID: PMC7823995 DOI: 10.3390/jof7010017] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/18/2020] [Accepted: 12/23/2020] [Indexed: 11/16/2022] Open
Abstract
Invasive fungal infections (IFIs) are associated with high mortality rates and timely appropriate antifungal therapy is essential for good outcomes. Emerging antifungal resistance among Candida and Aspergillus spp., the major causes of IFI, is concerning and has led to the increasing incorporation of in vitro antifungal susceptibility testing (AST) to guide clinical decisions. However, the interpretation of AST results and their contribution to management of IFIs remains a matter of debate. Specifically, the utility of AST is limited by the delay in obtaining results and the lack of pharmacodynamic correlation between minimal inhibitory concentration (MIC) values and clinical outcome, particularly for molds. Clinical breakpoints for Candida spp. have been substantially revised over time and appear to be reliable for the detection of azole and echinocandin resistance and for outcome prediction, especially for non-neutropenic patients with candidemia. However, data are lacking for neutropenic patients with invasive candidiasis and some non-albicans Candida spp. (notably emerging Candida auris). For Aspergillus spp., AST is not routinely performed, but may be indicated according to the epidemiological context in the setting of emerging azole resistance among A. fumigatus. For non-Aspergillus molds (e.g., Mucorales, Fusarium or Scedosporium spp.), AST is not routinely recommended as interpretive criteria are lacking and many confounders, mainly host factors, seem to play a predominant role in responses to antifungal therapy. This review provides an overview of the pre-clinical and clinical pharmacodynamic data, which constitute the rationale for the use and interpretation of AST testing of yeasts and molds in clinical practice.
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Affiliation(s)
- Frederic Lamoth
- Infectious Diseases Service and Institute of Microbiology, University Hospital of Lausanne, Lausanne University, 1011 Lausanne, Switzerland;
| | - Russell E. Lewis
- Clinic of Infectious Diseases, S’Orsola-Malpighi Hospital, Department of Medical and Surgical Sciences, University of Bologna, 40126 Bologna, Italy;
| | - Dimitrios P. Kontoyiannis
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Correspondence: ; Tel.: +1-713-792-6237; Fax: +1-713-745-6839
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11
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Antachopoulos C, Roilides E. Pharmacokinetics and Pharmacodynamics of Antifungal Agents in Neonates and Children. CURRENT FUNGAL INFECTION REPORTS 2020. [DOI: 10.1007/s12281-020-00402-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Pea F. From bench to bedside: Perspectives on the utility of pharmacokinetics/pharmacodynamics in predicting the efficacy of antifungals in invasive candidiasis. Mycoses 2020; 63:854-858. [PMID: 32472719 DOI: 10.1111/myc.13121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/16/2022]
Abstract
The aim of this perspective is to give an overlook on the utility of pharmacokinetics/pharmacodynamics (PK/PD) in predicting the efficacy of antifungals in invasive candidiasis. Overall, from the available literature it appears that bridging data of PK/PD of antifungals from the laboratory to the clinic for the treatment of invasive candidiasis are feasible only partially. Fluconazole is the only antifungal agent having the pharmacodynamic threshold of efficacy identified in experimental animal models convincingly validated in the clinical setting of invasive candidiasis as well. Conversely, for voriconazole and posaconazole data on this topic are very limited. For the echinocandins, robust PK/PD identified in the laboratory represented the rationale for defining differential clinical breakpoints of echinocandins against different species of Candida by the regulatory agencies. However, translation of the findings in the clinical setting provided conflicting results. Data on PK/PD of amphotericin B and flucytosine in models of invasive candidiasis are quite limited, and clinical studies assessing the role of drug exposure on efficacy are currently lacking. The expectation is that prospective studies could test more and more frequently the validity of experimental PK/PD data of antifungals in the clinical setting of invasive candidiasis. The findings could represent a step forward in addressing adequate antifungal stewardship programmes.
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Affiliation(s)
- Federico Pea
- Department of Medicine, University of Udine, Udine, Italy.,Institute of Clinical Pharmacology, Santa Maria della Misericordia University Hospital of Udine, ASUFC, Udine, Italy
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Toward Harmonization of Voriconazole CLSI and EUCAST Breakpoints for Candida albicans Using a Validated In Vitro Pharmacokinetic/Pharmacodynamic Model. Antimicrob Agents Chemother 2020; 64:AAC.00170-20. [PMID: 32229492 DOI: 10.1128/aac.00170-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/26/2020] [Indexed: 12/29/2022] Open
Abstract
CLSI and EUCAST susceptibility breakpoints for voriconazole and Candida albicans differ by one dilution (≤0.125 and ≤0.06 mg/liter, respectively) whereas the epidemiological cutoff values for EUCAST (ECOFF) and CLSI (ECV) are the same (0.03 mg/liter). We therefore determined the pharmacokinetic/pharmacodynamic (PK/PD) breakpoints of voriconazole against C. albicans for both methodologies with an in vitro PK/PD model, which was validated using existing animal PK/PD data. Four clinical wild-type and non-wild-type C. albicans isolates (voriconazole MICs, 0.008 to 0.125 mg/liter) were tested in an in vitro PK/PD model. For validation purposes, mouse PK were simulated and in vitro PD were compared with in vivo outcomes. Human PK were simulated, and the exposure-effect relationship area under the concentration-time curve for the free, unbound fraction of a drug from 0 to 24 h (fAUC0-24)/MIC was described for EUCAST and CLSI 24/48-h methods. PK/PD breakpoints were determined using the fAUC0-24/MIC associated with half-maximal activity (EI50) and Monte Carlo simulation analysis. The in vitro 24-h PD EI50 values of voriconazole against C. albicans were 2.5 to 5 (1.5 to 17) fAUC/MIC. However, the 72-h PD were higher at 133 (51 to 347) fAUC/MIC for EUCAST and 94 (35 to 252) fAUC/MIC for CLSI. The mean (95% confidence interval) probability of target attainment (PTA) was 100% (95 to 100%), 97% (72 to 100%), 83% (35 to 99%), and 49% (8 to 91%) for EUCAST and 100% (97 to 100%), 99% (85 to 100%), 91% (52 to 100%), and 68% (17 to 96%) for CLSI for MICs of 0.03, 0.06, 0.125, and 0.25 mg/liter, respectively. Significantly, >95% PTA values were found for EUCAST/CLSI MICs of ≤0.03 mg/liter. For MICs of 0.06 to 0.125 mg/liter, trough levels 1 to 4 mg/liter would be required to attain the PK/PD target. A PK/PD breakpoint of C. albicans voriconazole at the ECOFF/ECV of 0.03 mg/liter was determined for both the EUCAST and CLSI methods, indicating the need for breakpoint harmonization for the reference methodologies.
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Implications of Evolving and Emerging Pharmacokinetic-Pharmacodynamic Research for Triazoles and Echinocandins. CURRENT FUNGAL INFECTION REPORTS 2020. [DOI: 10.1007/s12281-020-00391-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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15
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Stevens VM, Mueller SW, Reynolds PM, MacLaren R, Kiser TH. Extrapolating Antifungal Animal Data to Humans - Is it reliable? CURRENT FUNGAL INFECTION REPORTS 2020; 14:50-62. [PMID: 32201545 PMCID: PMC7083583 DOI: 10.1007/s12281-020-00370-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW This article aimed to review animal models of antifungals and identifies human literature to assess if the extrapolation of results is reliable. RECENT FINDINGS Animal studies have helped identify AUC/MIC targets for new drugs and formulations such as isavuconazole and delayed release posaconazole that have translated to successful outcomes in humans. Models have also been influential in the identification of possible combination therapies for the treatment of aspergillosis, such as voriconazole and echinocandins. However, challenges are endured with animal models when it comes to replicating the pharmacokinetics of humans which has been exemplified with the newest itraconazole formulation. Additionally, animal models have displayed a survival benefit with the use of iron chelators and amphotericin for mucormycosis which was not demonstrated in humans. SUMMARY Animal models have been a staple in the development and optimization of antifungal agents. They afford the ability to investigate uncommon diseases, such as invasive fungal infections, that would otherwise take years and many resources to complete. Although there are many benefits of animal models there are also shortcomings. This is why the reliability of extrapolating data from animal models to humans is often scrutinized.
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Affiliation(s)
- Victoria M Stevens
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| | - Scott W Mueller
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| | - Paul M Reynolds
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| | - Robert MacLaren
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| | - Tyree H Kiser
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
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One Size Fits All? Application of Susceptible-Dose-Dependent Breakpoints to Pediatric Patients and Laboratory Reporting. J Clin Microbiol 2019; 58:JCM.01446-19. [PMID: 31666359 DOI: 10.1128/jcm.01446-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The Clinical and Laboratory Standards Institute antimicrobial and antifungal standards define a susceptible-dose-dependent (SDD) category for certain organisms and drug combinations. Reporting MICs within the SDD category suggests that treatment success is likely with increased drug exposure. These breakpoints are based on pharmacokinetic, pharmacodynamic, and clinical outcome data from adults and not pediatric patients. This commentary aims to discuss the implications of reporting SDD interpretations for pediatric patients and recommends laboratory reporting comments.
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Righi E, Carnelutti A, Baccarani U, Sartor A, Cojutti P, Bassetti M, Pea F. Treatment of Candida infections with fluconazole in adult liver transplant recipients: Is TDM-guided dosing adaptation helpful? Transpl Infect Dis 2019; 21:e13113. [PMID: 31106504 DOI: 10.1111/tid.13113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/24/2019] [Accepted: 05/02/2019] [Indexed: 12/18/2022]
Abstract
BACKGROUND Fluconazole represents a common antifungal option for the treatment of Candida infections in liver transplant recipients. Although adequate antifungal exposure is known to correlate with favorable outcomes in patients with invasive candidiasis, therapeutic drug monitoring (TDM) of fluconazole is currently not recommended. METHODS We conducted a retrospective study including adult liver transplant recipients receiving fluconazole for invasive candidiasis and undergoing TDM. We assessed the correlation between clinical variables, fluconazole trough plasma levels (Cmin ), and outcome. RESULTS Twenty-seven patients (74% males; median age 57 years) were included. Abdominal candidiasis was the most frequent infection (56%). Median duration of fluconazole therapy was 17 days (IQR 9-21). Fluconazole median Cmin was 11.0 mg/L (range 2.4-30.6 mg/L). Five (19%) patients required TDM-guided fluconazole dose increase. All-cause in hospital mortality was 33%. Fluconazole Cmin >11 mg/L significantly correlated with clinical success (OR 8.78, 95% CI 1.13-67.8, P = 0.04). CONCLUSIONS Our study identified decreased fluconazole Cmin as a factor associated with negative outcomes in liver transplant recipients with Candida infection. TDM of fluconazole may be advisable in this patient population.
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Affiliation(s)
- Elda Righi
- Infectious Diseases Division, Azienda Sanitaria Universitaria Integrata Santa Maria della Misericordia, Udine, Italy.,Infectious Diseases, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - Alessia Carnelutti
- Infectious Diseases Division, Azienda Sanitaria Universitaria Integrata Santa Maria della Misericordia, Udine, Italy
| | - Umberto Baccarani
- General Surgery and Transplantation Unit, Azienda Sanitaria Universitaria Integrata Santa Maria della Misericordia, Udine, Italy.,Department of Medicine, University of Udine, Udine, Italy
| | - Assunta Sartor
- Microbiology Unit, Azienda Sanitaria Universitaria Integrata Santa Maria della Misericordia, Udine, Italy
| | - Piergiorgio Cojutti
- Department of Medicine, University of Udine, Udine, Italy.,Institute of Clinical Pharmacology, Azienda Sanitaria Universitaria Integrata Santa Maria della Misericordia, Udine, Italy
| | - Matteo Bassetti
- Infectious Diseases Division, Azienda Sanitaria Universitaria Integrata Santa Maria della Misericordia, Udine, Italy.,Department of Medicine, University of Udine, Udine, Italy
| | - Federico Pea
- Department of Medicine, University of Udine, Udine, Italy.,Institute of Clinical Pharmacology, Azienda Sanitaria Universitaria Integrata Santa Maria della Misericordia, Udine, Italy
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18
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Population Pharmacokinetic Study of Prophylactic Fluconazole in Preterm Infants for Prevention of Invasive Candidiasis. Antimicrob Agents Chemother 2019; 63:AAC.01960-18. [PMID: 30910892 DOI: 10.1128/aac.01960-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 03/14/2019] [Indexed: 12/18/2022] Open
Abstract
Fluconazole is an antifungal agent with reported evidence for its prophylactic effect against systemic fungal infection in preterm infants. The aim of this study was to build a population pharmacokinetic model to evaluate the pharmacokinetic characteristics of intravenous and oral fluconazole in preterm infants with the current prophylactic fluconazole dosing regimen. A pharmacokinetic model was developed using 301 fluconazole concentrations from 75 preterm infants with a baseline body weight (WT) ranging from 0.5 to 1.5 kg and an estimated glomerular filtration rate (eGFR) ranging from 12.9 to 58.5 ml/min/1.73 m2 Eligible infants received an intravenous or oral dose of 3 mg/kg of body weight of fluconazole, twice weekly with a ≥72-h dose interval, for 4 weeks. The model was qualified with basic goodness-of-fit diagnostics, visual predictive checks, and bootstrapping. The fluconazole pharmacokinetics was well described with a one-compartment linear model with a proportional residual error. The population clearance (CL) and volume of distribution (V) were derived as 0.0197 × (WT/1.00)0.746 × (eGFR/25.0)0.463 × exp(η) and 1.04 × WT × exp(η), respectively. Such covariate analyses augment the awareness of the need for personalized dosing in preterm infants. (This study has been registered at ClinicalTrials.gov under identifier NCT01683760).
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Pharmacokinetics of Caspofungin in Critically Ill Patients in Relation to Liver Dysfunction: Differential Impact of Plasma Albumin and Bilirubin Levels. Antimicrob Agents Chemother 2019; 63:AAC.02466-18. [PMID: 30962329 DOI: 10.1128/aac.02466-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 03/02/2019] [Indexed: 01/13/2023] Open
Abstract
Caspofungin has a liver-dependent metabolism. Reduction of the dose is recommended based on Child-Pugh (C-P) score. In critically ill patients, drug pharmacokinetics (PK) may be altered. The aim of this study was to investigate the prevalence of abnormal liver function tests, increased C-P scores, their effects on caspofungin PK, and whether pharmacokinetic-pharmacodynamic (PK/PD) targets were attained in patients with suspected candidiasis. Intensive care unit patients receiving caspofungin were prospectively included. PK parameters were determined on days 2, 5, and 10, and their correlations to the individual liver function tests and the C-P score were analyzed. Forty-six patients were included with C-P class A (n = 5), B (n = 40), and C (n = 1). On day 5 (steady state), the median and interquartile range for area under the curve from 0 to 24 h (AUC0-24), clearance (CL), and central volume of distribution (V 1) were 57.8 (51.6 to 69.8) mg·h/liter, 0.88 (0.78 to 1.04) liters/h, and 11.9 (9.6 to 13.1) liters, respectively. The C-P score did not correlate with AUC0-24 (r = 0.03; P = 0.84), CL (r = -0.07; P = 0.68), or V 1 (r = 0.19; P = 0.26), but there was a bilirubin-driven negative correlation with the elimination rate constant (r = -0.46; P = 0.004). Hypoalbuminemia correlated with low AUC0-24 (r = 0.45; P = 0.005) and was associated with higher clearance (r = -0.31; P = 0.062) and somewhat higher V 1 (r = -0.15; P = 0.37), resulting in a negative correlation with the elimination rate constant (r = -0.34; P = 0.042). For Candida strains with minimal inhibitory concentrations of ≥0.064 μg/ml, PK/PD targets were not attained in all patients. The caspofungin dose should not be reduced in critically ill patients in the absence of cirrhosis, and we advise against the use of the C-P score in patients with trauma- or sepsis-induced liver injury.
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20
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A Systematic Screen Reveals a Diverse Collection of Medications That Induce Antifungal Resistance in Candida Species. Antimicrob Agents Chemother 2019; 63:AAC.00054-19. [PMID: 30858206 DOI: 10.1128/aac.00054-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 03/07/2019] [Indexed: 01/16/2023] Open
Abstract
The increasing incidence of and high mortality rates associated with invasive fungal infections (IFIs) impose an enormous clinical, social, and economic burden on humankind. In addition to microbiological resistance to existing antifungal drugs, the large number of unexplained treatment failures is a serious concern. Due to the extremely limited therapeutic options available, it is critical to identify and understand the various causes of treatment failure if patient outcomes are to improve. In this study, we examined one potential source of treatment failure: antagonistic drug interactions. Using a simple screen, we systematically identified currently approved medications that undermine the antifungal activity of three major antifungal drugs-fluconazole, caspofungin, and amphotericin B-on four prevalent human fungal pathogens-Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis This revealed that a diverse collection of structurally distinct drugs exhibit antagonistic interactions with fluconazole. Several antagonistic agents selected for follow-up studies induce azole resistance through a mechanism that depends on Tac1p/Pdr1p zinc-cluster transcription factors, which activate the expression of drug efflux pumps belonging to the ABC-type transporter family. Few antagonistic interactions were identified with caspofungin or amphotericin B, possibly reflecting their cell surface mode of action that should not be affected by drug efflux mechanisms. Given that patients at greatest risk of IFIs usually receive a multitude of drugs to treat various underlying conditions, these studies suggest that chemically inducible azole resistance may be much more common and important than previously realized.
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21
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Synthesis and in vitro biological evaluation of 1,3-bis-(1,2,3-triazol-1-yl)-propan-2-ol derivatives as antifungal compounds fluconazole analogues. Med Chem Res 2019. [DOI: 10.1007/s00044-019-02317-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Pea F, Lewis RE. Overview of antifungal dosing in invasive candidiasis. J Antimicrob Chemother 2019; 73:i33-i43. [PMID: 29304210 DOI: 10.1093/jac/dkx447] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In the past, most antifungal therapy dosing recommendations for invasive candidiasis followed a 'one-size fits all' approach with recommendations for lowering maintenance dosages for some antifungals in the setting of renal or hepatic impairment. A growing body of pharmacokinetic/pharmacodynamic research, however now points to a widespread 'silent epidemic' of antifungal underdosing for invasive candidiasis, especially among critically ill patients or special populations who have altered volume of distribution, protein binding and drug clearance. In this review, we explore how current adult dosing recommendations for antifungal therapy in invasive candidiasis have evolved, and special populations where new approaches to dose optimization or therapeutic drug monitoring may be needed, especially in light of increasing antifungal resistance among Candida spp.
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Affiliation(s)
- Federico Pea
- Institute of Clinical Pharmacology, Santa Maria della Misericordia University Hospital of Udine, ASUIUD, Udine, Italy.,Department of Medicine, University of Udine, Udine, Italy
| | - Russell E Lewis
- Infectious Diseases Unit, S. Orsola-Malpighi Hospital; Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
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23
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Are In Vitro Susceptibilities to Azole Antifungals Predictive of Clinical Outcome in the Treatment of Candidemia? J Clin Microbiol 2018; 56:JCM.01072-18. [PMID: 30135234 DOI: 10.1128/jcm.01072-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The purpose of this review is to critically analyze published data evaluating the impact of azole pharmacokinetic and pharmacodynamic parameters, MICs, and Candida species on clinical outcomes in patients with candidemia. Clinical breakpoints (CBPs) for fluconazole and voriconazole, which are used to determine susceptibility, have been defined by the Clinical and Laboratory Standards Institute (CLSI) for Candida species. Studies evaluating the relationship between treatment efficacy and in vitro susceptibility, as well as the pharmacodynamic targets, have been conducted in patients treated with fluconazole for candidemia; however, for species other than Candida albicans and Candida glabrata, and for other forms of invasive candidiasis, data remain limited and randomized trials are not available. Limited data evaluating these relationships with voriconazole are available. While pharmacodynamic targets for posaconazole and isavuconazole have been proposed based upon studies conducted in murine models, CBPs have not been established by CLSI. Fluconazole remains an important antifungal agent for the treatment of candidemia, and data supporting its use based on in vitro susceptibility are growing, particularly for C. albicans and C. glabrata Further investigation is needed to establish the roles of voriconazole, posaconazole, and isavuconazole in the treatment of candidemia and for all agents in the treatment of other forms of invasive candidiasis.
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24
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Population Pharmacokinetics and Cerebrospinal Fluid Penetration of Fluconazole in Adults with Cryptococcal Meningitis. Antimicrob Agents Chemother 2018; 62:AAC.00885-18. [PMID: 29914943 PMCID: PMC6125572 DOI: 10.1128/aac.00885-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/08/2018] [Indexed: 01/26/2023] Open
Abstract
Robust population pharmacokinetic (PK) data for fluconazole are scarce. The variability of fluconazole penetration into the central nervous system (CNS) is not known. Robust population pharmacokinetic (PK) data for fluconazole are scarce. The variability of fluconazole penetration into the central nervous system (CNS) is not known. A fluconazole PK study was conducted in 43 patients receiving oral fluconazole (usually 800 mg every 24 h [q24h]) in combination with amphotericin B deoxycholate (1 mg/kg q24h) for cryptococcal meningitis (CM). A four-compartment PK model was developed, and Monte Carlo simulations were performed for a range of fluconazole dosages. A meta-analysis of trials reporting outcomes of CM patients treated with fluconazole monotherapy was performed. Adjusted for bioavailability, the PK parameter means (standard deviation) were the following: clearance, 0.72 (0.24) liters/h; volume of the central compartment, 18.07 (6.31) liters; volume of the CNS compartment, 32.07 (17.60) liters; first-order rate constant from the central to peripheral compartment, 12.20 (11.17) h−1, from the peripheral to central compartment, 18.10 (8.25) h−1, from the central to CNS compartment, 35.43 (13.74) h−1, and from the CNS to central the compartment, 28.63 (10.03) h−1. Simulations of the area under concentration-time curve resulted in median (interquartile range) values of 1,143.2 (range, 988.4 to 1,378.0) mg · h/liter in plasma (AUCplasma) and 982.9 (range, 781.0 to 1,185.9) mg · h/liter in cerebrospinal fluid (AUCCSF) after a dosage of 1,200 mg q24h. The mean simulated ratio of AUCCSF/AUCplasma was 0.89 (standard deviation [SD], 0.44). The recommended dosage of fluconazole for CM induction therapy fails to attain the pharmacodynamic (PD) target in respect to the wild-type MIC distribution for C. neoformans. The meta-analysis suggested modest improvements in both CSF sterility and mortality outcomes with escalating dosage. This study provides the pharmacodynamic rationale for the long-recognized fact that fluconazole monotherapy is an inadequate induction regimen for CM.
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25
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Watt KM, Cohen-Wolkowiez M, Barrett JS, Sevestre M, Zhao P, Brouwer KLR, Edginton AN. Physiologically Based Pharmacokinetic Approach to Determine Dosing on Extracorporeal Life Support: Fluconazole in Children on ECMO. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2018; 7:629-637. [PMID: 30033691 PMCID: PMC6202466 DOI: 10.1002/psp4.12338] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Extracorporeal life support (e.g., dialysis, extracorporeal membrane oxygenation (ECMO)) can affect drug disposition, placing patients at risk for therapeutic failure. In this population, dose selection to achieve safe and effective drug exposure is difficult. We developed a novel and flexible approach that uses physiologically based pharmacokinetic (PBPK) modeling to translate results from ECMO ex vivo experiments into bedside dosing recommendations. To determine fluconazole dosing in children on ECMO, we developed a PBPK model, which was validated using fluconazole pharmacokinetic (PK) data in adults and critically ill infants. Next, an ECMO compartment was added to the PBPK model and parameterized using data from a previously published ex vivo study. Simulations using the final ECMO PBPK model reasonably characterized observed PK data in infants on ECMO, and the model was used to derive dosing in children on ECMO across the pediatric age spectrum. This approach can be generalized to other forms of extracorporeal life support (ECLS), such as dialysis.
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Affiliation(s)
- Kevin M Watt
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Michael Cohen-Wolkowiez
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
| | | | | | - Ping Zhao
- Bill and Melinda Gates Foundation, Seattle, Washington, USA
| | - Kim L R Brouwer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA
| | - Andrea N Edginton
- University of Waterloo School of Pharmacy, Waterloo, Ontario, Canada
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In Vivo Pharmacokinetics and Pharmacodynamics of APX001 against Candida spp. in a Neutropenic Disseminated Candidiasis Mouse Model. Antimicrob Agents Chemother 2018; 62:AAC.02542-17. [PMID: 29378706 DOI: 10.1128/aac.02542-17] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 01/22/2018] [Indexed: 01/26/2023] Open
Abstract
APX001 is the prodrug of APX001A, which is a first-in-class small molecule with a unique mechanism of action that inhibits the fungal enzyme Gwt1 in the glycosylphosphatidylinositol (GPI) biosynthesis pathway. The goal of the present study was to determine which pharmacokinetic/pharmacodynamic (PK/PD) index and magnitude best correlated with efficacy in the murine disseminated candidiasis model for Candida albicans (n = 5), C. glabrata (n = 5), and C. auris (n = 4). MIC values ranged from 0.002 to 0.03 mg/liter for C. albicans, from 0.008 to 0.06 mg/liter for C. glabrata, and from 0.004 to 0.03 mg/liter for C. auris Plasma APX001A pharmacokinetic measurements were performed in mice after oral administration of 4, 16, 64, and 256 mg/kg of body weight APX001. Single-dose pharmacokinetic studies exhibited maximum plasma concentration (Cmax) values of 0.46 to 15.6 mg/liter, area under the concentration-time curve (AUC) from time zero to infinity (AUC0-inf) values of 0.87 to 70.0 mg · h/liter, and half-lives of 1.40 to 2.75 h. A neutropenic murine disseminated candidiasis model was utilized for all treatment studies, and drug dosing was by the oral route. Dose fractionation was performed against C. albicans K1, with total doses ranging from 4 to 1,024 mg/kg/day of APX001 fractionated into regimens of dosing every 3, 6, 8, and 12 h for a 24-h treatment duration. Nonlinear regression analysis was used to determine which PK/PD index best correlated with efficacy on the basis of the reduction in the number of CFU/kidney at 24 h. The 24-h free-drug AUC/MIC ratio (fAUC0-24/MIC) was the PK/PD index that best correlated with efficacy (coefficient of determination [R2] = 0.88). Treatment studies with the remaining strains utilized regimens of 1 to 256 mg/kg of APX001 administered every 6 h for a 24-h duration with C. albicans and a 96-h study duration with C. glabrata and C. auris The dose required to achieve 50% of the maximum effect (ED50) and stasis fAUC/MIC targets were as follows: for C. albicans, 3.67 ± 3.19 and 20.60 ± 6.50, respectively; for C. glabrata, 0.38 ± 0.21 and 1.31 ± 0.27, respectively; and for C. auris, 7.14 ± 4.54 and 14.67 ± 8.30, respectively. The present studies demonstrated in vitro and in vivo APX001A and APX001 potency, respectively, against C. albicans, C. glabrata, and C. auris. These results have potential relevance for clinical dose selection and evaluation of susceptibility breakpoints. The identification of a lower AUC/MIC ratio target for C. glabrata suggests that species-specific susceptibility breakpoints should be explored.
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In Vitro Human Onychopharmacokinetic and Pharmacodynamic Analyses of ME1111, a New Topical Agent for Onychomycosis. Antimicrob Agents Chemother 2017; 62:AAC.00779-17. [PMID: 29084749 DOI: 10.1128/aac.00779-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 10/22/2017] [Indexed: 11/20/2022] Open
Abstract
ME1111 is a novel antifungal agent currently under clinical development as a topical onychomycosis treatment. A major challenge in the application of topical onychomycotics is penetration and dissemination of antifungal agent into the infected nail plate and bed. In this study, pharmacokinetic/pharmacodynamic parameters of ME1111 that potentially correlate with clinical efficacy were compared with those of marketed topical onychomycosis antifungal agents: efinaconazole, tavaborole, ciclopirox, and amorolfine. An ME1111 solution and other launched topical formulations were applied to an in vitro dose model for 14 days based on their clinical dose and administration. Drug concentrations in the deep layer of the nail and within the cotton pads beneath the nails were measured using liquid chromatography-tandem mass spectrometry. Concentrations of ME1111 in the nail and cotton pads were much higher than those of efinaconazole, ciclopirox, and amorolfine. Free drug concentrations of ME1111 in deep nail layers and cotton pads were orders of magnitude higher than the MIC90 value against Trichophyton rubrum (n = 30). Unlike other drugs, the in vitro antifungal activity of ME1111 was not affected by 5% human keratin and under a mild acidic condition (pH 5.0). The in vitro antidermatophytic efficacy coefficients (ratio of free drug concentration to MIC90s against T. rubrum) of ME1111, as measured in deep nail layers, were significantly higher than those of efinaconazole, tavaborole, ciclopirox, and amorolfine (P < 0.05). This suggests that ME1111 has excellent permeation of human nails and, consequently, the potential to be an effective topical onychomycosis treatment.
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28
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Pharmacodynamic Optimization for Treatment of Invasive Candida auris Infection. Antimicrob Agents Chemother 2017; 61:AAC.00791-17. [PMID: 28584152 DOI: 10.1128/aac.00791-17] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 05/28/2017] [Indexed: 11/20/2022] Open
Abstract
Candida auris is an emerging multidrug-resistant threat. The pharmacodynamics of three antifungal classes against nine C. auris strains was explored using a murine invasive candidiasis model. The total drug median pharmacodynamic (PD) target associated with net stasis was a fluconazole AUC/MIC (the area under the concentration-time curve over 24 h in the steady state divided by the MIC) of 26, an amphotericin B Cmax/MIC (maximum concentration of drug in serum divided by the MIC) of 0.9, and a micafungin AUC/MIC of 54. The micafungin PD targets for C. auris were ≥20-fold lower than those of other Candida species in this animal model. Clinically relevant micafungin exposures produced the most killing among the three classes.
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Fernández-Ruiz M, Guinea J, Lora-Pablos D, Zaragoza Ó, Puig-Asensio M, Almirante B, Cuenca-Estrella M, Aguado JM. Impact of fluconazole susceptibility on the outcome of patients with candidaemia: data from a population-based surveillance. Clin Microbiol Infect 2017; 23:672.e1-672.e11. [PMID: 28143788 DOI: 10.1016/j.cmi.2017.01.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 01/05/2017] [Accepted: 01/21/2017] [Indexed: 02/08/2023]
Abstract
OBJECTIVES The clinical correlation of fluconazole antifungal susceptibility testing (AST) for Candida isolates and its integration with pharmacokinetics/pharmacodynamics (PK/PD) parameters is unclear. We analysed the impact of fluconazole minimum inhibitory concentration (MIC) values, 24-hour area under the concentration-time curve (AUC24) and AUC24/MIC ratio on the outcome of candidemic patients. METHODS We included 257 episodes of candidaemia treated with fluconazole monotherapy for ≥72 hours from a population-based surveillance conducted in 29 hospitals (CANDIPOP Project). AST was centrally performed by European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) microdilution methods. Primary outcome was clinical failure (30-day mortality and/or persistent candidaemia for ≥72 hours from initiation of therapy). Secondary outcomes included early (3-7 days) and late (3-30 days) mortality. RESULTS Rates of clinical failure, early and late mortality among evaluable episodes were 32.3% (80/248), 3.1% (8/257) and 23.4% (59/248). There was no relationship between fluconazole MIC values or PK/PD parameters and clinical failure. Although MIC values ≥2 mg/L by EUCAST (positive predictive value 32.1%, negative predictive value 68.7%) and ≥0.5 mg/L by CLSI (positive predictive value 34.8%, negative predictive value 74.4%) appeared to be optimal for predicting clinical failure, no significant associations remained after multivariate adjustment (odds ratio 1.67; 95% confidence interval 0.48-5.79; p 0.423). Lack of association was consistent for alternative thresholds (including proposed clinical breakpoints). The only association found for secondary outcomes was between an AUC24/MIC ratio >400 h by CLSI and early mortality (odds ratio 0.18; 95% confidence interval 0.04-0.98; p 0.026). CONCLUSIONS High fluconazole MIC values did not negatively impact outcome of patients with candidaemia treated with fluconazole. No effect of PK/PD targets on the risk of clinical failure was found.
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Affiliation(s)
- M Fernández-Ruiz
- Unit of Infectious Diseases, Hospital Universitario '12 de Octubre', Instituto de Investigación Hospital '12 de Octubre' (i+12), Universidad Complutense, Madrid, Spain.
| | - J Guinea
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario 'Gregorio Marañón', Universidad Complutense, Madrid, Spain
| | - D Lora-Pablos
- Unit of Clinical Research, Hospital Universitario '12 de Octubre', Instituto de Investigación Hospital '12 de Octubre' (i+12), Madrid, Spain; CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Ó Zaragoza
- Department of Mycology, Spanish National Center for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - M Puig-Asensio
- Department of Infectious Diseases, Hospital Universitari 'Vall d'Hebron', Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - B Almirante
- Department of Infectious Diseases, Hospital Universitari 'Vall d'Hebron', Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - M Cuenca-Estrella
- Department of Mycology, Spanish National Center for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - J M Aguado
- Unit of Infectious Diseases, Hospital Universitario '12 de Octubre', Instituto de Investigación Hospital '12 de Octubre' (i+12), Universidad Complutense, Madrid, Spain
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Gonzalez JM, Rodriguez CA, Agudelo M, Zuluaga AF, Vesga O. Antifungal pharmacodynamics: Latin America's perspective. Braz J Infect Dis 2016; 21:79-87. [PMID: 27821250 PMCID: PMC9425464 DOI: 10.1016/j.bjid.2016.09.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 09/14/2016] [Accepted: 09/19/2016] [Indexed: 11/23/2022] Open
Abstract
The current increment of invasive fungal infections and the availability of new broad-spectrum antifungal agents has increased the use of these agents by non-expert practitioners, without an impact on mortality. To improve efficacy while minimizing prescription errors and to reduce the high monetary cost to the health systems, the principles of pharmacokinetics (PK) and pharmacodynamics (PD) are necessary. A systematic review of the PD of antifungals agents was performed aiming at the practicing physician without expertise in this field. The initial section of this review focuses on the general concepts of antimicrobial PD. In vitro studies, fungal susceptibility and antifungal serum concentrations are related with different doses and dosing schedules, determining the PD indices and the magnitude required to obtain a specific outcome. Herein the PD of the most used antifungal drug classes in Latin America (polyenes, azoles, and echinocandins) is discussed.
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Affiliation(s)
- Javier M Gonzalez
- Clinica CARDIO VID, Medellín, Colombia; Universidad de Antioquia, Facultad de Medicina, Grupo Investigador de Problemas en Enfermedades Infecciosas (GRIPE), Medellín, Colombia
| | - Carlos A Rodriguez
- Universidad de Antioquia, Facultad de Medicina, Grupo Investigador de Problemas en Enfermedades Infecciosas (GRIPE), Medellín, Colombia
| | - Maria Agudelo
- Universidad de Antioquia, Facultad de Medicina, Grupo Investigador de Problemas en Enfermedades Infecciosas (GRIPE), Medellín, Colombia; Hospital Universitario San Vicente Fundación, Unidad de Enfermedades Infecciosas, Medellín, Colombia
| | - Andres F Zuluaga
- Universidad de Antioquia, Facultad de Medicina, Grupo Investigador de Problemas en Enfermedades Infecciosas (GRIPE), Medellín, Colombia
| | - Omar Vesga
- Universidad de Antioquia, Facultad de Medicina, Grupo Investigador de Problemas en Enfermedades Infecciosas (GRIPE), Medellín, Colombia; Hospital Universitario San Vicente Fundación, Unidad de Enfermedades Infecciosas, Medellín, Colombia.
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Effect of Obesity on the Population Pharmacokinetics of Fluconazole in Critically Ill Patients. Antimicrob Agents Chemother 2016; 60:6550-6557. [PMID: 27550344 DOI: 10.1128/aac.01088-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 08/12/2016] [Indexed: 12/21/2022] Open
Abstract
Our objective was to describe the population pharmacokinetics of fluconazole in a cohort of critically ill nonobese, obese, and morbidly obese patients. Critically ill patients prescribed fluconazole were recruited into three body mass index (BMI) cohorts, nonobese (18.5 to 29.9 kg/m2), obese (30.0 to 39.9 kg/m2), and morbidly obese (≥40 kg/m2). Serial fluconazole concentrations were determined using a validated chromatographic method. Population pharmacokinetic analysis and Monte Carlo dosing simulations were undertaken with Pmetrics. Twenty-one critically ill patients (11 male) were enrolled, including obese (n = 6) and morbidly obese (n = 4) patients. The patients mean ± standard deviation (SD) age, weight, and BMI were 54 ± 15 years, 90 ± 24 kg, and 31 ± 9 kg/m2, respectively. A two-compartment linear model described the data adequately. The mean ± SD population pharmacokinetic parameter estimates were clearance (CL) of 0.95 ± 0.48 liter/h, volume of distribution of the central compartment (Vc) of 15.10 ± 11.78 liter, intercompartmental clearance from the central to peripheral compartment of 5.41 ± 2.28 liter/h, and intercompartmental clearance from the peripheral to central compartment of 2.92 ± 4.95 liter/h. A fluconazole dose of 200 mg daily was insufficient to achieve an area under the concentration-time curve for the free, unbound drug fraction/MIC ratio of 100 for pathogens with MICs of ≥2 mg/liter in patients with BMI of >30 kg/m2 A fluconazole loading dose of 12 mg/kg and maintenance dose of 6 mg/kg/day achieved pharmacodynamic targets for higher MICs. A weight-based loading dose of 12 mg/kg followed by a daily maintenance dose of 6 mg/kg, according to renal function, is required in critically ill patients for pathogens with a MIC of 2 mg/liter.
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Thomson P, Mayayo E, López-Fernández L, Guarro J, Capilla J. Combined antifungal therapy against systemic murine infections by rare Cryptococcus species. Mycoses 2016; 60:112-117. [PMID: 27696562 DOI: 10.1111/myc.12569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 11/28/2022]
Abstract
Cryptococcus albidus and Cryptococcus laurentii are uncommon species of this genus that in recent decades have increasingly caused opportunistic infections in humans, mainly in immunocompromised patients; the best therapy for such infection being unknown. Using a murine model of systemic infection by these fungi, we have evaluated the efficacy of amphotericin B (AMB) at 0.8 mg/kg, administered intravenously, fluconazole (FLC) or voriconazole (VRC), both administered orally, at 25 mg/kg and the combination of AMB plus VRC against three C. albidus and two C. laurentii strains. All the treatments significantly reduced the fungal burden in all the organs studied. The combination showed a synergistic effect in the reduction in fungal load, working better than both monotherapies. The histopathological study confirmed the efficacy of the treatments.
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Affiliation(s)
- Pamela Thomson
- Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, IISPV; Universitat Rovira i Virgili, Reus, Tarragona, Spain
| | - Emilio Mayayo
- Unitat d'Anatomia Patològica, Facultat de Medicina i Ciències de la Salut, IISPV; Universitat Rovira i Virgili, Reus, Tarragona, Spain
| | - Loida López-Fernández
- Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, IISPV; Universitat Rovira i Virgili, Reus, Tarragona, Spain
| | - Josep Guarro
- Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, IISPV; Universitat Rovira i Virgili, Reus, Tarragona, Spain
| | - Javier Capilla
- Unitat de Microbiologia, Facultat de Medicina i Ciències de la Salut, IISPV; Universitat Rovira i Virgili, Reus, Tarragona, Spain
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Cota JM, FakhriRavari A, Rowan MP, Chung KK, Murray CK, Akers KS. Intravenous Antibiotic and Antifungal Agent Pharmacokinetic-Pharmacodynamic Dosing in Adults with Severe Burn Injury. Clin Ther 2016; 38:2016-31. [PMID: 27586127 DOI: 10.1016/j.clinthera.2016.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/30/2016] [Accepted: 08/01/2016] [Indexed: 12/22/2022]
Abstract
PURPOSE Despite advances in the care of patients with severe burn injury, infection-related morbidity and mortality remain high and can potentially be reduced with antimicrobial dosing optimized for the infecting pathogen. However, anti-infective dose selection is difficult because of the highly abnormal physiologic features of burn patients, which can greatly affect the pharmacokinetic (PK) disposition of these agents. We review published PK data from burn patients and offer evidence-based dosing recommendations for antimicrobial agents in burn-injured patients. METHODS Because most infections occur at least 48 hours after initial burn injury and anti-infective therapy often lasts ≥10 days, we reviewed published data informing PK-pharmacodynamic (PD) dosing of anti-infectives administered during the second, hypermetabolic stage of burn injury, in those with >20% total body surface area burns, and in those with normal or augmented renal clearance (estimated creatinine clearance ≥130 mL/min). Analyses were performed using 10,000-patient Monte Carlo simulations, which uses PK variability observed in burn patients and MIC data to determine the probability of reaching predefined PK-PD targets. The probability of target attainment, defined as the likelihood that an anti-infective dosing regimen would achieve a specific PK-PD target at the single highest susceptible MIC, and the cumulative fraction of response, defined as the population probability of target attainment given a specific dose and a distribution of MICs, were calculated for each recommended anti-infective dosing regimen. FINDINGS Evidence-based doses were derived for burn-injured patients for 15 antibiotics and 2 antifungal agents. Published data were unavailable or insufficient for several agents important to the care of burn patients, including newer antifungal and antipseudomonal agents. Furthermore, available data suggest that antimicrobial PK properties in burned patients is highly variable. We recommend that, where possible, therapeutic drug monitoring be performed to optimize PK-PD parameter achievement in individual patients. IMPLICATIONS Given the high variability in PK disposition observed in burn patients, doses recommended in the package insert may not achieve PK-PD parameters associated with optimal infectious outcomes. Our study is limited by the necessity for fixed assumptions in depicting this highly variable patient population. New rapid-turnaround analytical technology is needed to expand the menu of antimicrobial agents for which therapeutic drug monitoring is available to guide dose modification within a clinically actionable time frame.
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Affiliation(s)
- Jason M Cota
- University of the Incarnate Word, Feik School of Pharmacy, San Antonio, Texas
| | | | - Matthew P Rowan
- US Army Institute of Surgical Research, Fort Sam Houston, Texas
| | - Kevin K Chung
- US Army Institute of Surgical Research, Fort Sam Houston, Texas
| | | | - Kevin S Akers
- US Army Institute of Surgical Research, Fort Sam Houston, Texas.
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Hope W, Drusano GL, Rex JH. Pharmacodynamics for antifungal drug development: an approach for acceleration, risk minimization and demonstration of causality. J Antimicrob Chemother 2016; 71:3008-3019. [PMID: 27494925 DOI: 10.1093/jac/dkw298] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The treatment of invasive fungal diseases constitutes a significant unmet medical need. There are relatively few antifungal agents in clinical development and a paucity of novel targets. Morbidity and mortality remain high and clinical outcomes are compromised by submaximal efficacy, emergence of drug resistance and drug-related toxicity. Thus, new antifungal agents are urgently required. A deep understanding of exposure-response relationships underpins the development of safe and effective clinical regimens of any therapeutic agent. Pharmacokinetics (PK) and pharmacodynamics (PD) is increasingly recognized as a vital tool in the development of new antimicrobial agents and maximizes the probability that the right dose will be studied the first time. There is currently no information or agreement as to what constitutes an adequate PK/PD package for the development of a new antifungal agent. This review provides a summary of the achievements of antifungal PK/PD for the treatment of invasive candidiasis, invasive aspergillosis and cryptococcal meningoencephalitis, and outlines the necessary components of a PK/PD package for a new antifungal agent. Such information is critical for the accelerated and efficient development of new agents and enables improved clinical outcomes to be secured.
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Affiliation(s)
| | | | - John H Rex
- AstraZeneca Pharmaceuticals, Waltham, MA, USA.,F2G Pharmaceuticals, Eccles, Cheshire, UK
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35
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Santos JRA, César IC, Costa MC, Ribeiro NQ, Holanda RA, Ramos LH, Freitas GJC, Paixão TA, Pianetti GA, Santos DA. Pharmacokinetics/pharmacodynamic correlations of fluconazole in murine model of cryptococcosis. Eur J Pharm Sci 2016; 92:235-43. [PMID: 27235581 DOI: 10.1016/j.ejps.2016.05.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/20/2016] [Accepted: 05/24/2016] [Indexed: 01/15/2023]
Abstract
The emergence of fluconazole-resistant Cryptococcus gattii is a global concern, since this azole is the main antifungal used worldwide to treat patients with cryptococcosis. Although pharmacokinetic (PK) and pharmacodynamic (PD) indices are useful predictive factors for therapeutic outcomes, there is a scarcity of data regarding PK/PD analysis of antifungals in cryptococcosis caused by resistant strains. In this study, PK/PD parameters were determined in a murine model of cryptococcosis caused by resistant C. gattii. We developed and validated a suitable liquid chromatography-electrospray ionization tandem mass spectrometry method for PK studies of fluconazole in the serum, lungs, and brain of uninfected mice. Mice were infected with susceptible or resistant C. gattii, and the effects of different doses of fluconazole on the pulmonary and central nervous system fungal burden were determined. The peak levels in the serum, lungs, and brain were achieved within 0.5h. The AUC/MIC index (area under the curve/minimum inhibitory concentration) was associated with the outcome of anti-cryptococcal therapy. Interestingly, the maximum concentration of fluconazole in the brain was lower than the MIC for both strains. In addition, the treatment of mice infected with the resistant strain was ineffective even when high doses of fluconazole were used or when amphotericin B was tested, confirming the cross-resistance between these drugs. Altogether, our novel data provide the correlation of PK/PD parameters with antifungal therapy during cryptococcosis caused by resistant C. gattii.
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Affiliation(s)
- Julliana Ribeiro Alves Santos
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; Laboratório de Micologia, Universidade Ceuma (UNICEUMA), São Luís, Maranhão, Brazil
| | - Isabela Costa César
- Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Marliete Carvalho Costa
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Noelly Queiroz Ribeiro
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo Assunção Holanda
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Lais Hott Ramos
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Gustavo José Cota Freitas
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Tatiane Alves Paixão
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Gerson Antônio Pianetti
- Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Daniel Assis Santos
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
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Targeting Fibronectin To Disrupt In Vivo Candida albicans Biofilms. Antimicrob Agents Chemother 2016; 60:3152-5. [PMID: 26902759 DOI: 10.1128/aac.03094-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 02/14/2016] [Indexed: 11/20/2022] Open
Abstract
New drug targets are of great interest for the treatment of fungal biofilms, which are routinely resistant to antifungal therapies. We theorized that the interaction of Candida albicans with matricellular host proteins would provide a novel target. Here, we show that an inhibitory protein (FUD) targeting Candida-fibronectin interactions disrupts biofilm formation in vitro and in vivo in a rat venous catheter model. The peptide appears to act by blocking the surface adhesion of Candida, halting biofilm formation.
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Jager NGL, van Hest RM, Lipman J, Taccone FS, Roberts JA. Therapeutic drug monitoring of anti-infective agents in critically ill patients. Expert Rev Clin Pharmacol 2016; 9:961-79. [PMID: 27018631 DOI: 10.1586/17512433.2016.1172209] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Initial adequate anti-infective therapy is associated with significantly improved clinical outcomes for patients with severe infections. However, in critically ill patients, several pathophysiological and/or iatrogenic factors may affect the pharmacokinetics of anti-infective agents leading to suboptimal drug exposure, in particular during the early phase of therapy. Therapeutic drug monitoring (TDM) may assist to overcome this problem. We discuss the available evidence on the use of TDM in critically ill patient populations for a number of anti-infective agents, including aminoglycosides, β-lactams, glycopeptides, antifungals and antivirals. Also, we present the available evidence on the practices of anti-infective TDM and describe the potential utility of TDM to improve treatment outcome in critically ill patients with severe infections. For aminoglycosides, glycopeptides and voriconazole, beneficial effects of TDM have been established on both drug effectiveness and potential side effects. However, for other drugs, therapeutic ranges need to be further defined to optimize treatment prescription in this setting.
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Affiliation(s)
- Nynke G L Jager
- a Department of Pharmacy , Academic Medical Center , Amsterdam , The Netherlands
| | - Reinier M van Hest
- a Department of Pharmacy , Academic Medical Center , Amsterdam , The Netherlands
| | - Jeffrey Lipman
- b Burns Trauma and Critical Care Research Centre , The University of Queensland , Brisbane , Australia.,c Departments of Pharmacy and Intensive Care , Royal Brisbane and Women's Hospital , Brisbane , Australia
| | - Fabio S Taccone
- d Department of Intensive Care, Hopital Erasme , Université Libre de Bruxelles (ULB) , Brussels , Belgium
| | - Jason A Roberts
- b Burns Trauma and Critical Care Research Centre , The University of Queensland , Brisbane , Australia.,c Departments of Pharmacy and Intensive Care , Royal Brisbane and Women's Hospital , Brisbane , Australia.,e School of Pharmacy , The University of Queensland , Brisbane , Australia
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Efficacy of Extended-Interval Dosing of Micafungin Evaluated Using a Pharmacokinetic/Pharmacodynamic Study with Humanized Doses in Mice. Antimicrob Agents Chemother 2015; 60:674-7. [PMID: 26552968 DOI: 10.1128/aac.02124-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/01/2015] [Indexed: 11/20/2022] Open
Abstract
The pharmacokinetic/pharmacodynamic (PK/PD) characteristics of the echinocandins favor infrequent administration of large doses. The in vivo investigation reported here tested the utility of a range of humanized dose levels of micafungin using a variety of prolonged dosing intervals for the prevention and therapy of established disseminated candidiasis. Humanized doses of 600 mg administered every 6 days prevented fungal growth in prophylaxis. Humanized doses of 300 to 1,000 mg administered every 6 days demonstrated efficacy for established infections.
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Rybak JM, Marx KR, Nishimoto AT, Rogers PD. Isavuconazole: Pharmacology, Pharmacodynamics, and Current Clinical Experience with a New Triazole Antifungal Agent. Pharmacotherapy 2015; 35:1037-51. [DOI: 10.1002/phar.1652] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jeffrey M. Rybak
- Department of Clinical Pharmacy; University of Tennessee Health Science Center; Memphis Tennessee
| | - Kayleigh R. Marx
- Division of Pharmacy; University of Texas MD Anderson Cancer Center; Houston Texas
| | - Andrew T. Nishimoto
- Department of Clinical Pharmacy; University of Tennessee Health Science Center; Memphis Tennessee
| | - P. David Rogers
- Department of Clinical Pharmacy; University of Tennessee Health Science Center; Memphis Tennessee
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Host contributions to construction of three device-associated Candida albicans biofilms. Infect Immun 2015; 83:4630-8. [PMID: 26371129 DOI: 10.1128/iai.00931-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/09/2015] [Indexed: 01/05/2023] Open
Abstract
Among the most fascinating virulence attributes of Candida is the ability to transition to a biofilm lifestyle. As a biofilm, Candida cells adhere to a surface, such as a vascular catheter, and become encased in an extracellular matrix. During this mode of growth, Candida resists the normal immune response, often causing devastating disease. Based on scanning electron microscopy images, we hypothesized that host cells and proteins become incorporated into clinical biofilms. As a means to gain an understanding of these host-biofilm interactions, we explored biofilm-associated host components by using microscopy and liquid chromatography-mass spectrometry. Here we characterize the host proteins associated with several in vivo rat Candida albicans biofilms, including those from vascular catheter, denture, and urinary catheter models as well as uninfected devices. A conserved group of 14 host proteins were found to be more abundant during infection at each of the niches. The host proteins were leukocyte and erythrocyte associated and included proteins involved in inflammation, such as C-reactive protein, myeloperoxidase, and alarmin S100-A9. A group of 59 proteins were associated with both infected and uninfected devices, and these included matricellular and inflammatory proteins. In addition, site-specific proteins were identified, such as amylase in association with the denture device. Cellular analysis revealed neutrophils as the predominant leukocytes associating with biofilms. These experiments demonstrate that host cells and proteins are key components of in vivo Candida biofilms, likely with one subset associating with the device and another being recruited by the proliferating biofilm.
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Brosh-Nissimov T, Ben-Ami R. Differential association of fluconazole dose and dose/MIC ratio with mortality in patients with Candida albicans and non-albicans bloodstream infection. Clin Microbiol Infect 2015; 21:1011-7. [PMID: 26183300 DOI: 10.1016/j.cmi.2015.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/26/2015] [Accepted: 07/03/2015] [Indexed: 10/23/2022]
Abstract
Targeting fluconazole therapy to achieve predefined pharmacodynamic goals has been suggested as a means of optimizing the treatment of patients with candidaemia. However, data regarding species-specific dosing targets are inconclusive. We retrospectively analysed a cohort of 75 adult patients with Candida bloodstream infection (BSI) who received initial treatment with fluconazole for ≥48 h (36 Candida albicans and 39 non-albicans Candida (NAC)). Fluconazole dose, the dose/MIC ratio and the 24-h area under the concentration-time curve (AUC24)/MIC ratio were determined for each patient, and classification and regression tree analysis was used to determine breakpoints for significant interactions with 30-day survival. Both fluconazole exposure parameters and patient-related and disease-related variables were assessed in univariable and multivariable survival models. The crude 30-day mortality rate was 32% (44% and 21% for C. albicans and NAC, respectively). An average fluconazole dose of >200 mg/day, a dose/MIC ratio of >400 and an AUC24/MIC ratio of >400 were associated with a higher 30-day survival rate and better microbiological response in patients with C. albicans BSI but not in those with NAC BSI. Baseline chronic kidney disease was a risk factor for fluconazole underdosing and mortality. Severity of sepsis (Sequential Organ Failure Assessment score) was the only significant predictor of death in patients with NAC BSI. We conclude that, although pharmacodynamic target-directed fluconazole dosing may help to optimize outcomes for patients with C. albicans BSI, additional studies are needed to define the role of fluconazole in the treatment of NAC BSI.
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Affiliation(s)
- T Brosh-Nissimov
- Infectious Disease Unit, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
| | - R Ben-Ami
- Infectious Disease Unit, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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Watt KM, Gonzalez D, Benjamin DK, Brouwer KLR, Wade KC, Capparelli E, Barrett J, Cohen-Wolkowiez M. Fluconazole population pharmacokinetics and dosing for prevention and treatment of invasive Candidiasis in children supported with extracorporeal membrane oxygenation. Antimicrob Agents Chemother 2015; 59:3935-43. [PMID: 25896706 PMCID: PMC4468733 DOI: 10.1128/aac.00102-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/13/2015] [Indexed: 12/24/2022] Open
Abstract
Candida infections are a leading cause of infectious disease-related death in children supported by extracorporeal membrane oxygenation (ECMO). The ECMO circuit can alter drug pharmacokinetics (PK); thus, standard fluconazole dosing may result in suboptimal drug exposures. The objective of our study was to determine the PK of fluconazole in children on ECMO. Forty children with 367 PK samples were included in the analysis. The PK data were analyzed using nonlinear mixed-effect modeling (NONMEM). A one-compartment model best described the data. Weight was included in the base model for clearance (CL) and volume of distribution (V). The final model included the effect of serum creatinine (SCR) level on CL and the effect of ECMO on V as follows: CL (in liters per hour) = 0.019 × weight × (SCR/0.4)(-0.29) × exp(ηCL) and V (in liters) = 0.93 × weight × 1.4(ECMO) × exp(ηV). The fluconazole V was increased in children supported by ECMO. Consequently, children on ECMO require a higher fluconazole loading dose for prophylaxis (12 mg/kg of body weight) and treatment (35 mg/kg) paired with standard maintenance doses to achieve exposures similar to those of children not on ECMO.
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Affiliation(s)
- Kevin M Watt
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Daniel Gonzalez
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Daniel K Benjamin
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Kim L R Brouwer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Kelly C Wade
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Edmund Capparelli
- Department of Pediatrics, University of California, San Diego, La Jolla, California, USA
| | - Jeffrey Barrett
- Division of Clinical Pharmacology and Therapeutics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Michael Cohen-Wolkowiez
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
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Davis SA, Vincent BM, Endo MM, Whitesell L, Marchillo K, Andes DR, Lindquist S, Burke MD. Nontoxic antimicrobials that evade drug resistance. Nat Chem Biol 2015; 11:481-7. [PMID: 26030729 PMCID: PMC4472574 DOI: 10.1038/nchembio.1821] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 04/10/2015] [Indexed: 01/21/2023]
Abstract
Drugs that act more promiscuously provide fewer routes for the emergence of resistant mutants. But this benefit often comes at the cost of serious off-target and dose-limiting toxicities. The classic example is the antifungal amphotericin B (AmB), which has evaded resistance for more than half a century. We report dramatically less toxic amphotericins that nevertheless evade resistance. They are scalably accessed in just three steps from the natural product, and bind their target (the fungal sterol, ergosterol) with far greater selectivity than AmB. Hence, they are less toxic and far more effective in a mouse model of systemic candidiasis. Surprisingly, exhaustive efforts to select for mutants resistant to these more selective compounds revealed that they are just as impervious to resistance as AmB. Thus, highly selective cytocidal action and the evasion of resistance are not mutually exclusive, suggesting practical routes to the discovery of less toxic, resistance-evasive therapies.
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Affiliation(s)
- Stephen A Davis
- 1] Howard Hughes Medical Institute, Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. [2] Roger Adam Laboratory, Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Benjamin M Vincent
- 1] Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA. [2] Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA
| | - Matthew M Endo
- 1] Howard Hughes Medical Institute, Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. [2] Roger Adam Laboratory, Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Luke Whitesell
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA
| | - Karen Marchillo
- 1] Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA. [2] Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - David R Andes
- 1] Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA. [2] Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Susan Lindquist
- 1] Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA. [2] Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Martin D Burke
- 1] Howard Hughes Medical Institute, Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. [2] Roger Adam Laboratory, Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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Therapeutic drug monitoring for triazoles: A needs assessment review and recommendations from a Canadian perspective. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2015; 25:327-43. [PMID: 25587296 PMCID: PMC4277162 DOI: 10.1155/2014/340586] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Invasive fungal infections cause significant morbidity and mortality in patients with concomitant underlying immunosuppressive diseases. The recent addition of new triazoles to the antifungal armamentarium has allowed for extended-spectrum activity and flexibility of administration. Over the years, clinical use has raised concerns about the degree of drug exposure following standard approved drug dosing, questioning the need for therapeutic drug monitoring (TDM). Accordingly, the present guidelines focus on TDM of triazole antifungal agents. A review of the rationale for triazole TDM, the targeted patient populations and available laboratory methods, as well as practical recommendations based on current evidence from an extended literature review are provided in the present document.
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Pharmacodynamic target evaluation of a novel oral glucan synthase inhibitor, SCY-078 (MK-3118), using an in vivo murine invasive candidiasis model. Antimicrob Agents Chemother 2014; 59:1265-72. [PMID: 25512406 DOI: 10.1128/aac.04445-14] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Echinocandins inhibit the synthesis of β-1,3-D-glucan in Candida and are the first-line therapy in numerous clinical settings. Their use is limited by poor oral bioavailability, and they are available only as intravenous therapies. Derivatives of enfumafungin are novel orally bioavailable glucan synthase inhibitors. We performed an in vivo pharmacodynamic (PD) evaluation with a novel enfumafungin derivative, SCY-078 (formerly MK-3118), in a well-established neutropenic murine model of invasive candidiasis against C. albicans, C. glabrata, and C. parapsilosis. The SCY-078 MICs varied 8-fold. Oral doses of 3.125 to 200 mg/kg SCY-078 salt in sterile water produced peak levels of 0.04 to 2.66 μg/ml, elimination half-lives of 5.8 to 8.5 h, areas under the concentration-time curve from 0 to 24 h (AUC0-24 h) of 0.61 to 41.10 μg·h/ml, and AUC from 0 to infinity (AUC0-∞) values of 0.68 to 40.31 μg·h/ml. The pharmacokinetics (PK) were approximately linear over the dose range studied. Maximum response (Emax) and PK/PD target identification studies were performed with 4 C. albicans, 4 C. glabrata, and 3 C. parapsilosis isolates. The PD index AUC/MIC was explored by using total (tAUC) and free (fAUC) drug concentrations. The maximum responses were 4.0, 4.0, and 4.3 log10 CFU/kidney reductions for C. albicans, C. glabrata, and C. parapsilosis, respectively. The AUC/MIC was a robust predictor of efficacy (R2, 0.53 to 0.91). The 24-h PD targets were a static dose of 63.5 mg/kg, a tAUC/MIC of 500, and an fAUC/MIC of 1.0 for C. albicans; a static dose of 58.4 mg/kg, a tAUC/MIC of 315, and an fAUC/MIC of 0.63 for C. glabrata; and a static dose of 84.4 mg/kg, a tAUC/MIC of 198, and an fAUC/MIC of 0.40 for C. parapsilosis. The mean fAUC/MIC values associated with a 1-log kill endpoint against these species were 1.42, 1.26, and 0.91 for C. albicans, C. glabrata, and C. parapsilosis, respectively. The static and 1-log kill endpoints were measured relative to the burden at the start of therapy. The static and 1-log kill doses, as well as the total and free drug AUC/MIC PD targets, were not statistically different between species but were numerically lower than those observed for echinocandins. SCY-078 is a promising novel oral glucan synthase inhibitor against Candida species, and further investigation is warranted.
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Pharmacokinetics and pharmacodynamics of antifungals in children and their clinical implications. Clin Pharmacokinet 2014; 53:429-54. [PMID: 24595533 DOI: 10.1007/s40262-014-0139-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Invasive fungal infections are a significant cause of morbidity and mortality in children. Successful management of these systemic infections requires identification of the causative pathogen, appropriate antifungal selection, and optimisation of its pharmacokinetic and pharmacodynamic properties to maximise its antifungal activity and minimise toxicity and the emergence of resistance. This review highlights salient scientific advancements in paediatric antifungal pharmacotherapies and focuses on pharmacokinetic and pharmacodynamic studies that underpin current clinical decision making. Four classes of drugs are widely used in the treatment of invasive fungal infections in children, including the polyenes, triazoles, pyrimidine analogues and echinocandins. Several lipidic formulations of the polyene amphotericin B have substantially reduced the toxicity associated with the traditional amphotericin B formulation. Monotherapy with the pyrimidine analogue flucytosine rapidly promotes the emergence of resistance and cannot be recommended. However, when used in combination with other antifungal agents, therapeutic drug monitoring of flucytosine has been shown to reduce high peak flucytosine concentrations, which are strongly associated with toxicity. The triazoles feature large inter-individual pharmacokinetic variability, although this pattern is less pronounced with fluconazole. In clinical trials, posaconazole was associated with fewer adverse effects than other members of the triazole family, though both posaconazole and itraconazole display erratic absorption that is influenced by gastric pH and the gastric emptying rate. Limited data suggest that the clinical response to therapy may be improved with higher plasma posaconazole and itraconazole concentrations. For voriconazole, pharmacokinetic studies among children have revealed that children require twice the recommended adult dose to achieve comparable blood concentrations. Voriconazole clearance is also affected by the cytochrome P450 (CYP) 2C19 genotype and hepatic impairment. Therapeutic drug monitoring is recommended as voriconazole pharmacokinetics are highly variable and small dose increases can result in marked changes in plasma concentrations. For the echinocandins, the primary source of pharmacokinetic variability stems from an age-dependent decrease in clearance with increasing age. Consequently, young children require larger doses per kilogram of body weight than older children and adults. Routine therapeutic drug monitoring for the echinocandins is not recommended. The effectiveness of many systemic antifungal agents has been correlated with pharmacodynamic targets in in vitro and in murine models of invasive candidiasis and aspergillosis. Further study is needed to translate these findings into optimal dosing regimens for children and to understand how these agents interact when multiple antifungal agents are used in combination.
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Abstract
Successful treatment of infectious diseases requires choice of the most suitable antimicrobial agent, comprising consideration of drug pharmacokinetics (PK), including penetration into infection site, pathogen susceptibility, optimal route of drug administration, drug dose, frequency of administration, duration of therapy, and drug toxicity. Antimicrobial pharmacokinetic/pharmacodynamic (PK/PD) studies consider these variables and have been useful in drug development, optimizing dosing regimens, determining susceptibility breakpoints, and limiting toxicity of antifungal therapy. Here the concepts of antifungal PK/PD studies are reviewed, with emphasis on methodology and application. The initial sections of this review focus on principles and methodology. Then the pharmacodynamics of each major antifungal drug class (polyenes, flucytosine, azoles, and echinocandins) is discussed. Finally, the review discusses novel areas of pharmacodynamic investigation in the study and application of combination therapy.
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Clinical validation of the analysis of fluconazole in oral fluid in hospitalized children. Antimicrob Agents Chemother 2014; 58:6742-6. [PMID: 25182638 DOI: 10.1128/aac.03636-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fluconazole is a first-line antifungal agent for the treatment and prophylaxis of invasive candidiasis in pediatric patients. Pediatric patients are at risk of suboptimal drug exposure, due to developmental changes in gastrointestinal and renal function, metabolic capacity, and volume of distribution. Therapeutic drug monitoring (TDM) can therefore be useful to prevent underexposure of fluconazole in children and infants. Children, however, often fear needles and can have difficult vascular access. The purpose of this study was to develop and clinically validate a method of analysis to determine fluconazole in oral fluid in pediatric patients. Twenty-one paired serum and oral fluid samples were obtained from 19 patients and were analyzed using a validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) method after cross-validation between serum and oral fluid. The results were within accepted ranges for accuracy and precision, and samples were stable at room temperature for at least 17 days. A Pearson correlation test for the fluconazole concentrations in serum and oral fluid showed a correlation coefficient of 0.960 (P < 0.01). The mean oral fluid-to-serum concentration ratio was 0.99 (95% confidence interval [CI], 0.88 to 1.10) with Bland-Altman analysis. In conclusion, an oral fluid method of analysis was successfully developed and clinically validated for fluconazole in pediatric patients and can be a noninvasive, painless alternative to perform TDM of fluconazole when blood sampling is not possible or desirable. When patients receive prolonged courses of antifungal treatment and use fluconazole at home, this method of analysis can extend the possibilities of TDM for patients at home.
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Abstract
Indwelling urinary catheters are commonly used in the management of hospitalized patients. Candida can adhere to the device surface and propagate as a biofilm. These Candida biofilm communities differ from free-floating Candida, exhibiting high tolerance to antifungal therapy. The significance of catheter-associated candiduria is often unclear, and treatment may be problematic considering the biofilm drug-resistant phenotype. Here we describe a rodent model for the study of urinary catheter-associated Candida albicans biofilm infection that mimics this common process in patients. In the setting of a functioning, indwelling urinary catheter in a rat, Candida proliferated as a biofilm on the device surface. Characteristic biofilm architecture was observed, including adherent, filamentous cells embedded in an extracellular matrix. Similar to what occurs in human patients, animals with this infection developed candiduria and pyuria. Infection progressed to cystitis, and a biofilmlike covering was observed over the bladder surface. Furthermore, large numbers of C. albicans cells were dispersed into the urine from either the catheter or bladder wall biofilm over the infection period. We successfully utilized the model to test the efficacy of antifungals, analyze transcriptional patterns, and examine the phenotype of a genetic mutant. The model should be useful for future investigations involving the pathogenesis, diagnosis, therapy, prevention, and drug resistance of Candida biofilms in the urinary tract.
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van der Elst KCM, Pereboom M, van den Heuvel ER, Kosterink JGW, Schölvinck EH, Alffenaar JWC. Insufficient fluconazole exposure in pediatric cancer patients and the need for therapeutic drug monitoring in critically ill children. Clin Infect Dis 2014; 59:1527-33. [PMID: 25148892 DOI: 10.1093/cid/ciu657] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Fluconazole is recommended as first-line treatment in invasive candidiasis in children and infants. Although timely achievement of adequate exposure of fluconazole improves outcome, therapeutic drug monitoring is currently not recommended. METHODS We conducted a retrospective study of critically ill children treated with fluconazole from January 2007 to October 2013 and for whom fluconazole concentrations were available. We collected demographic, clinical, and treatment data through review of the medical records and determined the correlation of clinical variables with the fluconazole concentration. Additionally, we assessed the relation between the fluconazole concentration and the time to culture conversion in patients with proven invasive candidiasis. RESULTS In total, 99 pediatric patients met the inclusion criteria. The fluconazole concentration was considered subtherapeutic in 40% of the patients. Multiple linear regression analysis showed a significant, independent, and positive association of the fluconazole trough concentration with the fluconazole dose (P <.001), weight (P = .009), and the serum urea concentration (P = .003), and a significant, independent, and negative association with age (P = .004) and cancer as an underlying condition (P = .003). A higher fluconazole concentration was associated with a shorter time to culture conversion (hazard ratio = 1.076 [95% confidence interval, 1.017-1.138]; P = .011). CONCLUSIONS The fluconazole concentration is not sufficient in pediatric cancer patients with the currently recommended dose regimen, and a higher fluconazole dose is required to achieve adequate drug exposure. Therapeutic drug monitoring of fluconazole can be a valuable tool to detect possible underexposure in critically ill children.
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Affiliation(s)
| | | | | | - Jos G W Kosterink
- Department of Clinical Pharmacy and Pharmacology Department of Pharmacy, Section of Pharmacotherapy and Pharmaceutical Care
| | - Elisabeth H Schölvinck
- Department of Pediatrics (Infection/Immunology), University Medical Center Groningen, University of Groningen, The Netherlands
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