Pharmacokinetic and maximum tolerated dose study of micafungin in combination with fluconazole versus fluconazole alone for prophylaxis of fungal infections in adult patients undergoing a bone marrow or peripheral stem cell transplant

Assessment of micafungin dosage regimens against Candida spp. in pediatric patients undergoing hematopoietic stem cell transplantation: a pharmacokinetic/pharmacodynamic analysis using Monte Carlo simulation

The objective of this study was to evaluate the efficacy of various micafungin dosing regimens against Candida spp. in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT). Monte Carlo simulations were conducted using pharmacokinetic (PK) parameters and pharmacodynamic (PD) data to determine the probabilities of target attainment and cumulative fractions of response in terms of area under the concentration curve/minimum inhibition concentration targets of micafungin. Current standard clinical micafungin dosing regimens of 1 and 2 mg/kg/day were appropriate for the prevention and treatment of Candida glabrata infection in pediatric patients undergoing HSCT, respectively. Moreover, the high-dose prophylactic dosage (2 mg/kg/day) and therapeutic dosage (4 mg/kg/day) should be the preferred option to optimize efficacy against Candida albicans. However, none of the simulated regimens was effective against Candida parapsilosis in pediatric HSCT patients. These PK/PD-based simulations rationalize and optimize the micafungin dosing regimens against Candida spp. in pediatric patients undergoing HSCT.

Absence of Clinically Meaningful Drug-Drug Interactions with Rezafungin: Outcome of Investigations

Rezafungin is a novel once-weekly echinocandin for intravenous injection currently in development for the treatment of Candida infections and the prevention of Candida, Aspergillus, and Pneumocystis infections in allogeneic blood and marrow transplant recipients. While in vitro data indicated that rezafungin exposure was unlikely to be affected by commonly prescribed medicines, interactions resulting in the altered systemic exposure of some drugs coadministered with rezafungin could not be excluded. Two phase 1 open label crossover studies, conducted in healthy subjects, examined drug interactions between rezafungin and multiple drug probe cytochrome P450 (CYP) substrates and/or transporter proteins, immunosuppressants, and cancer therapies. Statistical analysis compared the outcomes for drugs coadministered with rezafungin to those for the drugs administered alone. The geometric mean ratio was reported, and a default 90% confidence interval (CI) no-effect equivalence range of 80 to 125% was used for the maximal plasma concentration (Cmax), the area under the curve from time zero to the final sampling time point (AUC0-t), and the AUC from time zero to infinity (AUC0-∞). Most probes and concomitant drugs were within the equivalence range. For tacrolimus, ibrutinib, mycophenolic acid, and venetoclax, the AUC or Cmax was reduced (10 to 19%), with lower bounds of the 90% CI values falling outside the no-effect range. The rosuvastatin AUC and Cmax and the repaglinide AUC0-∞ were increased (12 to 16%), with the 90% CI being marginally above the upper bound. Overall, the in vitro and in vivo data demonstrated a low drug interaction potential with rezafungin via CYP substrate/transporter pathways and commonly prescribed comedications, suggesting that coadministration was unlikely to result in clinically significant effects. Treatment-emergent adverse events were typically mild, and rezafungin was generally well tolerated. IMPORTANCE Antifungal agents used to treat life-threatening infections are often associated with severe drug-drug interactions (DDIs) that may limit their usefulness. Rezafungin, a newly approved once-weekly echinocandin, has been shown to be free of DDIs based on extensive nonclinical and clinical testing described in this study.

Consensus guidelines for optimising antifungal drug delivery and monitoring to avoid toxicity and improve outcomes in patients with haematological malignancy and haemopoietic stem cell transplant recipients, 2021

Antifungal agents can have complex dosing and the potential for drug interaction, both of which can lead to subtherapeutic antifungal drug concentrations and poorer clinical outcomes for patients with haematological malignancy and haemopoietic stem cell transplant recipients. Antifungal agents can also be associated with significant toxicities when drug concentrations are too high. Suboptimal dosing can be minimised by clinical assessment, laboratory monitoring, avoidance of interacting drugs, and dose modification. Therapeutic drug monitoring (TDM) plays an increasingly important role in antifungal therapy, particularly for antifungal agents that have an established exposure-response relationship with either a narrow therapeutic window, large dose-exposure variability, cytochrome P450 gene polymorphism affecting drug metabolism, the presence of antifungal drug interactions or unexpected toxicity, and/or concerns for non-compliance or inadequate absorption of oral antifungals. These guidelines provide recommendations on antifungal drug monitoring and TDM-guided dosing adjustment for selected antifungal agents, and include suggested resources for identifying and analysing antifungal drug interactions. Recommended competencies for optimal interpretation of antifungal TDM and dose recommendations are also provided.

Pharmacokinetics and Antifungal Activity of Echinocandins in Ascites Fluid of Critically Ill Patients

The pharmacokinetics and antifungal activity of the echinocandins anidulafungin (AFG), micafungin (MFG), and caspofungin (CAS) were assessed in ascites fluid and plasma of critically ill adults treated for suspected or proven invasive candidiasis. Ascites fluid was obtained from ascites drains or during paracentesis. The antifungal activity of the echinocandins in ascites fluid was assessed by incubation of Candida albicans and Candida glabrata at concentrations of 0.03 to 16.00 μg/ml. In addition, ascites fluid samples obtained from our study patients were inoculated with the same isolates and evaluated for fungal growth. These patient samples had to be spiked with echinocandins to restore the original concentrations because echinocandins had been lost during sterile filtration. In ascites fluid specimens of 29 patients, echinocandin concentrations were below the simultaneous plasma levels. Serial sampling in 20 patients revealed a slower rise and decline of echinocandin concentrations in ascites fluid than in plasma. Proliferation of C. albicans in ascites fluid was slower than in culture medium and growth of C. glabrata was lacking, even in the absence of antifungals. In CAS-spiked ascites fluid samples, fungal CFU counts moderately declined, whereas spiking with AFG or MFG had no relevant effect. In ascites fluid of our study patients, echinocandin concentrations achieved by therapeutic doses did not result in a consistent eradication of C. albicans or C. glabrata. Thus, therapeutic doses of AFG, MFG, or CAS may result in ascites fluid concentrations preventing relevant proliferation of C. albicans and C. glabrata, but do not warrant reliable eradication.

Comparative Pharmacodynamics of Echinocandins against Aspergillus fumigatus Using an In Vitro Pharmacokinetic/Pharmacodynamic Model That Correlates with Clinical Response to Caspofungin Therapy: Is There a Place for Dose Optimization?

Echinocandins have been used as primary therapy of invasive aspergillosis (IA), with suboptimal results at standard dosing. Here, we explored the efficacy of dose escalation in a validated in vitro pharmacokinetic/pharmacodynamic (PK/PD) model. Six echinocandin wild-type (WT) and three non-WT A. fumigatus isolates were tested in an in vitro PK/PD model simulating anidulafungin, caspofungin, and micafungin exposures with a free drug maximum concentration (fCmax) of 0.01 to 16 mg/liter and a half-life (t1/2) of 8 to 22 h. The relationship between the area under the dosing interval time-free drug concentration curve (fAUC0-24)/minimum effective concentration (MEC) and % aberrant mycelium formation was analyzed. PK/PD indices associated with 50 to 99.99% maximal activity (EI50 to EI99.99) were correlated with the clinical outcome of a 50-mg/day standard dose of caspofungin. The probability of target attainment (PTA) was calculated for different dosing regimens of each echinocandin via Monte Carlo analysis. A sigmoidal PK/PD relationship was found for WT isolates with EI99 values of 766, 8.8, and 115 fAUC0-24/CLSI MEC for anidulafungin, caspofungin, and micafungin, respectively. No aberrant mycelia were observed for non-WT isolates, irrespective of their MEC and drug exposure. The EI99, EI99.9, and EI99.99 values corresponded to 2-, 3-, and 4-log10 formation of aberrant mycelia and correlated with survival, favorable, and complete response rates to caspofungin primary therapy in patients with IA. A very low PTA (<13%) was found for the standard doses of all echinocandins, whereas a PTA of ≥90% was found with 100 and 150 mg/day of caspofungin and 1,400 mg/day micafungin against WT isolates. For anidulafungin, the PTA for 1,500 mg/day was 10%. Among the three echinocandins, only caspofungin at 2 or 3 times the licensed dosing was associated with a high PTA. Caspofungin dose escalation might deserve clinical validation.

Optimization of Fluconazole Dosing for the Prevention and Treatment of Invasive Candidiasis Based on the Pharmacokinetics of Fluconazole in Critically Ill Patients

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.).

Comparison of Antifungal Prophylaxis Drugs in Patients With Hematological Disease or Undergoing Hematopoietic Stem Cell Transplantation: A Systematic Review and Network Meta-analysis

IMPORTANCE

Several antifungal drugs are available for antifungal prophylaxis in patients with hematological disease or who are undergoing hematopoietic stem cell transplantation (HSCT).

OBJECTIVE

To summarize the evidence on the efficacy and adverse effects of antifungal agents using an integrated comparison.

DATA SOURCES

Medline, EMBASE, and the Cochrane Central Register of Controlled Clinical Trials were searched to collect all relevant evidence published in randomized clinical trials that assessed antifungal prophylaxis in patients with hematological disease. Sources were search from inception up to October 2019.

STUDY SELECTION

Studies that compared any antifungal agent with a placebo, no antifungal agent, or another antifungal agent among patients with hematological disease or undergoing HSCT were included. Of 39 709 studies identified, 69 met the criteria for inclusion.

DATA EXTRACTION AND SYNTHESIS

The outcome from each study was estimated using the relative risk (RR) with 95% CIs. The Mantel-Haenszel random-effects model was used. The reliability and validity of the networks were estimated by addressing inconsistencies in the evidence from comparative studies of different treatments. Data were analyzed from December 2019 to February 2020. Reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses for Network Meta-analysis (PRISMA-NMA) guideline.

MAIN OUTCOMES AND MEASURES

The primary outcomes were invasive fungal infections (IFIs) and mortality. The secondary outcomes were fungal infections, proven IFIs, invasive candidiasis, invasive aspergillosis, fungi-related death, and withdrawal owing to adverse effects of the drug.

RESULTS

We identified 69 randomized clinical trials that reported comparisons of 12 treatments with at total of 14 789 patients. Posaconazole was the treatment associated with the best probability of success against IFIs (surface under the cumulative ranking curve, 86.7%; mean rank, 2.5). Posaconazole treatment was associated with a significant reduction in IFIs (RR, 0.57; 95% CI, 0.42-0.79) and invasive aspergillosis (RR, 0.36; 95% CI, 0.15-0.85) compared with placebo. Voriconazole was associated with a significant reduction in invasive candidiasis (RR, 0.15; 95% CI, 0.09-0.26) compared with placebo. However, posaconazole was associated with a higher incidence of withdrawal because of the adverse effects of the drug (surface under the cumulative ranking curve, 17.5%; mean rank, 9.2). In subgroup analyses considering efficacy and tolerance, voriconazole might be the best choice for patients undergoing HSCT, especially allogenic HSCT; however, posaconazole was ranked as the best choice for patients with acute myeloid leukemia or myelodysplastic syndrome.

CONCLUSIONS AND RELEVANCE

These findings suggest that voriconazole may be the best prophylaxis option for patients undergoing HSCT, and posaconazole may be the best prophylaxis option for patients with acute myeloid leukemia or myelodysplastic syndrome.

Population pharmacokinetics of micafungin over repeated doses in critically ill patients: a need for a loading dose?

OBJECTIVES

To study the population pharmacokinetics of micafungin in critically ill patients, evaluate and optimize dosage regimens.

METHODS

An HPLC-fluorescence bioassay for micafungin was developed, fully validated and applied to a pharmacokinetic study conducted in 14 ICU patients. Dense blood sampling was performed from days 1 to 7. A population pharmacokinetic model accounting for interindividual (IIV) and interoccasion variability (IOV) of the PK parameters was developed. Simulations were performed to estimate the probability of target attainment (PTA) for several dosing regimens.

KEY FINDINGS

A two-compartment pharmacokinetic model best described the data, with population clearance CL = 1.31 L/h and central volume V1 = 14.2 L. The relatively high IOV observed (45% for CL, 27% for V1) sets limits for the dose individualization in this population. The low PTA on the first day of treatment suggests the need of a loading dose. PTA and CFR estimates show that the current micafungin dosage may be insufficient for the treatment of borderline susceptible Candida strains.

CONCLUSIONS

A loading dose of up to 300 mg of micafungin is needed for the treatment of invasive candidiasis in ICU patients while a maintenance dose of up to 200 mg can be considered in empirical antifungal treatment.

Assessment of micafungin loading dosage regimens against Candida spp. in ICU patients by Monte Carlo simulations

OBJECTIVE

To assess the efficacy of loading dose on micafungin by simulating different dosage regimens.

METHODS

A published study of micafungin in ICU patients was employed to simulate nine different dosage regimens which were sorted out three groups in terms of three maintenance doses. Using pharmacokinetic parameters and pharmacodynamic data, 5000-subject Monte Carlo simulations were conducted to simulate concentration-time profiles of micafungin, calculate probabilities of target attainment (PTAs), and cumulative fractions of response (CFRs) in terms of AUC/MIC targets. PTAs were calculated using AUC/MIC cut-offs: 285 (Candida parapsilosis), 3000 (all Candida spp.), and 5000 (non-parapsilosis Candida spp.). PTA or CFR > 90% was considered optimal for a dosage regimen.

RESULTS

The concentration-time profiles of micafungin-simulated dosage regimens were obtained. PTA values were over 90% while applying the loading dose in each group of regimens: for Candida albicans and Candida glabrata (AUC/MIC = 5000), all regimens with loading dose provided PTAs of ≥ 90% for MIC ≤ 0.008 mg/L. The PTAs (AUC/MIC = 3000) were over 90% for MIC ≤ 0.008 mg/L in any regimen. However, for MIC inferior to 0.016 mg/L, only loading dosage regimens provided PTAs exceeding 90%. For C. parapsilosis (AUC/MIC = 285), the maximum MIC of achieving a PTA ≥ 90% was 0.25 mg/L both in the regimens of B (150 mg maintenance dose) and C (200 mg maintenance dose) with loading dose. In addition, CFR of any regimen with loading dose was ≥ 90% against C. albicans and C. glabrata. None of the dosage regimens achieved an expected CFR against C. parapsilosis.

CONCLUSIONS

The dosage regimen of micafungin which had a loading dose of 1.5 times was more suitable for ICU patients infected by Candida spp.

Extrapolating Antifungal Animal Data to Humans - Is it reliable?

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.

Bridging antifungal prophylaxis with 50 mg or 100 mg micafungin in allogeneic stem cell transplantation: A retrospective analysis

OBJECTIVE

Fluconazole or posaconazole is a standard of care in antifungal prophylaxis for patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). However, many patients need to interrupt standard prophylaxis due to intolerability, drug-drug interactions, or toxicity. Micafungin has come to prominence for these patients. However, the optimal biological dose of micafungin stays unclear.

METHODS

We retrospectively evaluated the efficacy of micafungin as antifungal prophylaxis in HSCT patients. Micafungin was applied as bridging in patients who were not eligible to receive oral posaconazole. Micafungin was either given at a dose of 100 mg or 50 mg SID.

RESULTS

A total of 173 patients received micafungin prophylaxis, 62 in the 100 mg and 111 in the 50 mg dose group. The incidence of probable or proven breakthrough IFDs during the observation period was one in the 100 mg and one in the 50 mg group. Fungal-free survival after 100 days was 98% and 99% (P = .842), and overall survival after 365 days was 60% and 63% (P = .8) respectively. In both groups, micafungin was well tolerated with no grade 3 or 4 toxicities.

CONCLUSION

In this retrospective analysis, which was not powered to detect non-inferiority, micafungin is effective and complements posaconazole as fungal prophylaxis in HSCT.

Quantification of anidulafungin and micafungin in human body fluids by high performance-liquid chromatography with UV-detection

The echinocandins anidulafungin (ANID) and micafungin (MICA) are recommended for treatment of invasive Candida infections. As target-site concentrations of antimicrobial agents are crucial for eradication of pathogens, we established and validated high-performance liquid chromatography-UV detection (HPLC-UV) assays for quantification of ANID and MICA in human plasma, ascites fluid, pleural effusion, and in cerebrospinal fluid (CSF). Sample pre-purification was performed by protein precipitation with acetonitrile followed by solid phase extraction. For both assays, intra- and interday precision, and accuracy fulfilled the requirements for bioanalytical methods issued by the European Medicine Agency (EMA). The lower limit of quantification was 0.01 mg/L for both drugs. At 25 °C, ANID and MICA concentrations declined by up to 70% within 24 h. Concentrations remained stable over 24 h at 4 °C and over four weeks at -80 °C. In conclusion, the developed methods are fit for the assessment of target-site pharmacokinetics of ANID and MICA in clinical studies.

Defining breakthrough invasive fungal infection-Position paper of the mycoses study group education and research consortium and the European Confederation of Medical Mycology

Breakthrough invasive fungal infections (IFIs) have emerged as a significant problem in patients receiving systemic antifungals; however, consensus criteria for defining breakthrough IFI are missing. This position paper establishes broadly applicable definitions of breakthrough IFI for clinical research. Representatives of the Mycoses Study Group Education and Research Consortium (MSG-ERC) and the European Confederation of Medical Mycology (ECMM) reviewed the relevant English literature for definitions applied and published through 2018. A draft proposal for definitions was developed and circulated to all members of the two organisations for comment and suggestions. The authors addressed comments received and circulated the updated document for approval. Breakthrough IFI was defined as any IFI occurring during exposure to an antifungal drug, including fungi outside the spectrum of activity of an antifungal. The time of breakthrough IFI was defined as the first attributable clinical sign or symptom, mycological finding or radiological feature. The period defining breakthrough IFI depends on pharmacokinetic properties and extends at least until one dosing interval after drug discontinuation. Persistent IFI describes IFI that is unchanged/stable since treatment initiation with ongoing need for antifungal therapy. It is distinct from refractory IFI, defined as progression of disease and therefore similar to non-response to treatment. Relapsed IFI occurs after treatment and is caused by the same pathogen at the same site, although dissemination can occur. These proposed definitions are intended to support the design of future clinical trials and epidemiological research in clinical mycology, with the ultimate goal of increasing the comparability of clinical trial results.

Extended Dosing Regimens for Fungal Prophylaxis

Invasive fungal diseases carry high morbidity and mortality in patients undergoing chemotherapy for hematological malignancies or allogeneic hematopoietic stem cell transplantation. In order to prevent these life-threatening infections, antifungal chemoprophylaxis plays an important role in daily clinical practice. Broad-spectrum antifungal triazoles are widely used but exhibit disadvantages such as relevant drug-drug interactions. Therefore, amphotericin B products or echinocandins can be an alternative in selected patient populations. As these compounds are available as intravenous formulations only, there is growing interest in extended dosing regimens. Although not approved for these agents, this strategy is a rational option, as these compounds have properties suitable for this strategy, including dose-proportional pharmacokinetics, prolonged elimination half-life, and a large therapeutic window. As the use of extended dosing regimens in antifungal prophylaxis is expanding in clinical practice, we reviewed the pharmacokinetic and pharmacodynamic rationale for this strategy, animal model data, dose escalation studies, and clinical trials supporting this concept.

Clinical Pharmacokinetics and Pharmacodynamics of Micafungin

Micafungin is a selective inhibitor of the synthesis of fungal 1,3-β-d-glucan, an essential component of the fungal cell wall. It is available as a powder for infusion only and is registered for the treatment of invasive and esophageal candidiasis in addition to prophylaxis of Candida infections in both adults and children. Average exposure after a single intravenous 100 mg dose in healthy adults is 133 mg h/L. Both exposure and maximum plasma concentration show linear dose proportional pharmacokinetics (PK) over a 0.15–8 mg/kg dose range. In healthy adults, the clearance (CL) is 10.4 mL/h/kg and volume of distribution is 0.2 L/kg; both are independent of the dose. Micafungin is metabolized by arylsulfatase, catechol-O-methyltransferase, and several cytochrome P450 (CYP) isoenzymes (3A4, 1A2, 2B6 and 2C), but no dose adjustments are necessary in patients with (severe) hepatic dysfunction. Exposure to micafungin is lower in hematology patients, and is even further lowered in critically ill patients (including burn patients) compared with healthy volunteers, which might have consequences for treatment efficacy. In children, an increased CL has been reported: 40–80 mL/h/kg in premature neonates and 20 mL/h/kg in children >4 months of age. Therefore, relatively higher doses of 4–10 mg/kg in premature neonates and 2–4 mg/kg in children with invasive candidiasis are used. However, these higher CLs may also be explained by the eightfold higher free fraction of unbound micafungin in premature neonates, meaning that an augmented dose might not be required.

Successful eradication of chronic symptomatic Candida krusei urinary tract infection with increased dose micafungin in a liver and kidney transplant recipient: Case report and review of the literature

Treatment of symptomatic candiduria is notoriously challenging because of the limited repository of antifungals that achieve adequate urinary concentrations. Fluconazole, amphotericin B-based products, and flucytosine are established treatment options for most Candida species. Candida krusei exhibits intrinsic resistance to fluconazole and decreased susceptibility to amphotericin B and flucytosine. In transplant patients, both amphotericin B-based products and flucytosine are less desirable because of their toxicities. Other triazole antifungals are unappealing because they do not achieve adequate urinary concentrations, have multiple toxicities, and interact with transplant-related immunosuppressive medications. Echinocandins are well-tolerated but have been traditionally deferred in the treatment of symptomatic funguria because of their poor urinary concentrations but there is a small but emerging body of literature supporting their use. Here, we present a case of successful eradication of chronic symptomatic C krusei urinary tract infection with micafungin 150 milligrams daily in a liver and kidney transplant recipient, and we review the literature on treatment of symptomatic candiduria.

Significantly Improved Pharmacokinetics Enhances In Vivo Efficacy of APX001 against Echinocandin- and Multidrug-Resistant Candida Isolates in a Mouse Model of Invasive Candidiasis

APX001 is a first-in-class, intravenous and orally available, broad-spectrum antifungal agent in clinical development for the treatment of life-threatening invasive fungal infections. The half-life of APX001A, the active moiety of APX001, is significantly shorter in mice than in humans (1.4 to 2.75 h in mice versus 2 to 2.5 days in humans), making the exploration of efficacy in mouse models difficult.

APX001 is a first-in-class, intravenous and orally available, broad-spectrum antifungal agent in clinical development for the treatment of life-threatening invasive fungal infections. The half-life of APX001A, the active moiety of APX001, is significantly shorter in mice than in humans (1.4 to 2.75 h in mice versus 2 to 2.5 days in humans), making the exploration of efficacy in mouse models difficult. After pretreatment with 1-aminobenzotriazole (ABT), a nonspecific cytochrome P450 inhibitor, greatly increased plasma APX001A exposure was observed in mice of different strains and of both genders. As a consequence, 26 mg/kg APX001 plus ABT sterilized kidneys in mice infected with Candida albicans, while APX001 alone at the same dose resulted in a modest burden reduction of only 0.2 log₁₀ CFU/g, relative to the vehicle control. In the presence of ABT, 2 days of once-daily dosing with APX001 at 26 mg/kg also demonstrated significant in vivo efficacy in the treatment of Candida glabrata infections in mice. Potent kidney burden reduction was achieved in mice infected with susceptible, echinocandin-resistant, or multidrug-resistant strains. In contrast, the standard of care (micafungin) was ineffective in treating infections caused by the resistant C. glabrata isolates.

Primary Fungal Prophylaxis in Hematological Malignancy: a Network Meta-Analysis of Randomized Controlled Trials

Several new antifungal agents have become available for primary fungal prophylaxis of neutropenia fever in hematological malignancy patients. Our aim was to synthesize all evidence on efficacy and enable an integrated comparison of all current treatments. We performed a systematic literature review to identify all publicly available evidence from randomized controlled trials (RCT). We searched Embase, PubMed, the Cochrane Central Register of Controlled Clinical Trials, and the www.ClinicalTrials.gov website. In total, 54 RCTs were identified, including 13 treatment options. The evidence was synthesized using a network meta-analysis. Relative risk (RR) was adopted. Posaconazole was ranked highest in effectiveness for primary prophylaxis, being the most favorable in terms of (i) the RR for reduction of invasive fungal infection (0.19; 95% confidence interval [CI], 0.11 to 0.36) and (ii) the probability of being the best option (94% of the cumulative ranking). Posaconazole also demonstrated its efficacy in preventing invasive aspergillosis and proven fungal infections, with RR of 0.13 (CI, 0.03 to 0.65) and 0.14 (CI, 0.05 to 0.38), respectively. However, there was no significant difference among all of the antifungal agents in all-cause mortality and overall adverse events. Our network meta-analysis provided an integrated overview of the relative efficacy of all available treatment options for primary fungal prophylaxis for neutropenic fever in hematological malignancy patients under myelosuppressive chemotherapy or hematopoietic cell transplantation. On the basis of this analysis, posaconazole seems to be the most effective prophylaxis option until additional data from head-to-head randomized controlled trials become available.

Mutant Prevention Concentration and Mutant Selection Window of Micafungin and Anidulafungin in Clinical Candida glabrata Isolates

We report the mutant prevention concentration (MPC) and mutant selection window (MSW) for micafungin and anidulafungin administered to treat Candida glabrata We also determine the mutation frequency. We studied 20 echinocandin-susceptible, fluconazole-intermediate, and FKS wild-type C. glabrata isolates. Adjusted inocula were stroked directly onto Sabouraud agar plates containing different concentrations of micafungin or anidulafungin and visually inspected daily for up to 5 days of incubation. Individual colonies growing on the plates containing echinocandins at 1 mg/liter were selected for antifungal susceptibility testing. The FKS genes of the resulting individual phenotypically resistant colonies were sequenced, and the MPC, MSW, and mutation frequency were determined. Biofilm was quantified, and the growth kinetics and virulence (Galleria mellonella model) of the resulting individual FKS mutant colonies were studied. For micafungin and anidulafungin, we found similar results for the MPC (0.06 to 2 mg/liter and 0.25 to 2 mg/liter, respectively), MSW (0.015 to 2 mg/liter for both echinocandins), and mutation frequency (3.7 × 10-8 and 2.8 × 10-8, respectively). A total of 12 isolates were able to grow at 1 mg/liter on echinocandin-containing plates, yielding a total of 32 phenotypically resistant colonies; however, FKS2 mutations (ΔF658, S663P, W715L, and E655A) were observed only in 21 colonies. We did not find differences in biofilm formation, the kinetic parameters studied, or the median survival of larvae infected by wild-type isolates and the resulting individual FKS2 mutant colonies. Echinocandin concentrations lower than 2 mg/liter can lead to selection of resistance mutations in C. glabrata isolates in vitro.

Ultrasound-assisted facile one-pot sequential synthesis of novel sulfonamide-isoxazoles using cerium (IV) ammonium nitrate (CAN) as an efficient oxidant in aqueous medium

A series of novel 3,5-disubstituted isoxazoles have been synthesized, using a new, green, and versatile "one-pot three-steps" methodology. The key step is an oxidative 1,3-dipolar cycloaddition under ultrasonic irradiation, occurring in aqueous media, and mediated by cerium (IV) ammonium nitrate (CAN). CAN is a one-electron oxidant, highly soluble in water, slightly toxic and inexpensive, that allows the in situ conversion of the intermediate aldoximes into nitrile oxide. The syntheses are highly regioselective, as illustrated by the structures of the final compounds, which have been fully assessed by spectral analyses (¹H and ¹³C NMR, MS). This study illustrates the potency of the ultrasound activation to synthesize a set of highly functionalized heterocycles, with potential applications in biology, in short reaction times and following an eco-friendly process.

Pharmacokinetics of antifungal drugs: practical implications for optimized treatment of patients

Introduction

Because of the high mortality of invasive fungal infections (IFIs), appropriate exposure to antifungals appears to be crucial for therapeutic efficacy and safety.

Materials and methods

This review summarises published pharmacokinetic data on systemically administered antifungals focusing on co-morbidities, target-site penetration, and combination antifungal therapy.

Conclusions and discussion

Amphotericin B is eliminated unchanged via urine and faeces. Flucytosine and fluconazole display low protein binding and are eliminated by the kidney. Itraconazole, voriconazole, posaconazole and isavuconazole are metabolised in the liver. Azoles are substrates and inhibitors of cytochrome P450 (CYP) isoenzymes and are therefore involved in numerous drug–drug interactions. Anidulafungin is spontaneously degraded in the plasma. Caspofungin and micafungin undergo enzymatic metabolism in the liver, which is independent of CYP. Although several drug–drug interactions occur during caspofungin and micafungin treatment, echinocandins display a lower potential for drug–drug interactions. Flucytosine and azoles penetrate into most of relevant tissues. Amphotericin B accumulates in the liver and in the spleen. Its concentrations in lung and kidney are intermediate and relatively low myocardium and brain. Tissue distribution of echinocandins is similar to that of amphotericin. Combination antifungal therapy is established for cryptococcosis but controversial in other IFIs such as invasive aspergillosis and mucormycosis.

Efficacy and safety of micafungin versus extensive azoles in the prevention and treatment of invasive fungal infections for neutropenia patients with hematological malignancies: A meta-analysis of randomized controlled trials

Background

Current studies that compare the efficacy and safety of micafungin (MCFG) with that of triazoles for the prophylaxis and treatment of invasive fungal infections (IFIs) demonstrate a lack of sufficient evidence and yield conflicting results. To compare the efficacy and safety of MCFG and triazoles in the prevention and treatment of IFIs, we conducted a meta-analysis and trial sequential analysis (TSA).

Methods

For the meta-analysis, we systematically searched the databases of PubMed, Embase and Cochrane Central Register of Controlled Trials and relevant database articles for randomized controlled studies published through November 2016. Comparative studies of the efficacy and safety of MCFG versus triazoles in the prevention and treatment of IFIs were selected. Meta-analysis was performed by R software with the “metafor” package. Pooled results were expressed as risk ratios (RRs) with corresponding 95% confidence intervals (CI). TSA was adopted to assess the studies’ power with TSA version 0.9 beta.

Results

Nine current studies were included in the meta-analysis (1049 cases and 959 controls). Pooled trial comparisons indicated that MCFG does have significantly higher treatment success rates (RR = 1.13; 95% CI, 1.02–1.25; p = 0.0205) and reduces the number of overall IFIs (RR = 0.75; 95% CI, 0.61–0.92; p = 0.0056). However, MCFG demonstrates no difference in all-cause mortality (RR = 0.76; 95% CI, 0.52–1.12, p = 0.1624). For the safety evaluation, MCFG had a significantly lower incidence of severe adverse events (AEs) (RR = 0.45; 95% CI, 0.25–0.83; p = 0.0105), hepatic impairment (RR = 0.70; 95% CI, 0.50–0.97; p = 0.0363) and premature discontinuation (RR = 0.51; 95% CI, 0.34–0.76, p = 0.0010). Meta-regression analysis disclosed the correction of mean age and treatment success rates (P < 0.0001). Meanwhile, TSA demonstrated sufficient power to show efficacy.

Conclusions

The treatment success rate of MCFG is superior to that of triazoles for the prophylaxis and treatment of IFIs, and correction of the mean patient age demonstrates that efficacy increases as patient age decreases. MCFG appears to be well-tolerated with manageable side effects and lower withdrawal rates. However, additional clinical trials should be conducted on specific drug-related mortality and AEs to gather sufficient evidence on these matters.

New facets of antifungal therapy

Invasive fungal infections remain a major cause of morbidity and mortality in immunocompromised patients, and such infections are a substantial burden to healthcare systems around the world. However, the clinically available armamentarium for invasive fungal diseases is limited to 3 main classes (i.e., polyenes, triazoles, and echinocandins), and each has defined limitations related to spectrum of activity, development of resistance, and toxicity. Further, current antifungal therapies are hampered by limited clinical efficacy, high rates of toxicity, and significant variability in pharmacokinetic properties. New antifungal agents, new formulations, and novel combination regimens may improve the care of patients in the future by providing improved strategies to combat challenges associated with currently available antifungal agents. Likewise, therapeutic drug monitoring may be helpful, but its present use remains controversial due to the lack of available data. This article discusses new facets of antifungal therapy with a focus on new antifungal formulations and the synergistic effects between drugs used in combination therapy.

Echinocandins: The Expanding Antifungal Armamentarium

The echinocandins are large lipopeptide molecules that, since their discovery approximately 41 years ago, have emerged as important additions to the expanding armamentarium against invasive fungal diseases. Echinocandins exert in vitro and in vivo fungicidal action against most Candida species and fungistatic action against Aspergillus species. However, the population of patients at risk for developing invasive fungal infections continues to increase. New therapeutic strategies using echinocandins are needed to improve clinical outcomes in patients with invasive fungal disease.

Single or 2-Dose Micafungin Regimen for Treatment of Invasive Candidiasis: Therapia Sterilisans Magna!

The time the earth takes to rotate its axis (the day) has dictated how often pharmaceutical compounds are dosed. The scientific link between the 2 events is materia medica arcana. As an example, in the treatment of invasive candidiasis, antifungal therapy with intravenous micafungin is dosed daily. A literature review revealed population pharmacokinetic analyses, in vivo pharmacokinetics/pharmacodynamics studies, and maximum-tolerated-dose studies of micafungin that examined optimal micafungin dosing strategies. The half-life of micafungin in patient blood was 14 hours in several studies, but was even longer in different organs, so that the concentration will persist above minimum inhibitory concentrations of Candida species for several days. Studies in mice and rabbits with persistent neutropenia and disseminated candidiasis, otherwise fatal, demonstrated that a single large dose of micafungin could clear disseminated candidiasis, even though the micafungin half-life in such animals is shorter than in humans. Human pharmacokinetics/pharmacodynamics studies confirmed this link between micafungin efficacy and the ratio of the area under the concentration-time curve, and the optimal exposures initially identified in neutropenic animals. Maximum tolerated dose studies have demonstrated safety of 900 mg administered daily for several weeks, whereas case reports demonstrate efficacy and safety of single 1400-mg doses. Thus, a single dose of micafungin, or 2 such doses within a few days of each other, is not only logical, but might even lead to faster clearance of Candida.

Development of New Strategies for Echinocandins: Progress in Translational Research

Echinocandins are N-acyl-substituted cyclic hexapeptides with potent in vitro and in vivo activity against Candida species that are used for primary treatment and prevention of candidemia and invasive candidiasis. Recent progress in the translational research of echinocandins has led to new approaches for treatment of central venous catheter Candida biofilms. Other studies have laid the experimental and clinical foundation for use of extended dosing intervals for administration of echinocandins in treatment and prevention of candidemia and invasive candidiasis.

[Echinocandins: Applied pharmacology]

The echinocandins share pharmacodynamic properties, although there are some interesting differences in their pharmacokinetic behaviour in the clinical practice. They are not absorbed by the oral route. They have a somewhat special distribution in the organism, as some of them can reach high intracellular concentrations while, with some others, the concentration is reduced. They are highly bound to plasma proteins, thus it is recommended to administer a loading dose for anidulafungin and caspofungin, although this procedure is not yet clear with micafungin. Echinocandins are excreted via a non-microsomal metabolism, so the urinary concentration is very low. Some carrier proteins that take part in the biliary clearance process are probably involved in the interactions described with caspofungin and micafungin. These two drugs must be used with caution in patients with severely impaired hepatic function, while all of them can be used without special precautions when there is renal impairment or the patient requires renal replacement therapy.

Prediction of micafungin area under the curve data by using peak concentration: applicability and utility in antifungal therapy

Aim: To describe a predictive model to obtain the area under the plasma concentration versus time curve (AUC) for micafungin to aid in dosing strategies in pediatric patients. Methods: Using published pharmacokinetic data a linear regression model to describe the Cmax versus AUCtau was developed. The mean absolute error prediction, root mean square error prediction along with correlation coefficient (r) and fold prediction criteria were used to evaluate the developed linear regression model for micafungin. Results: The predicted AUC for micafungin were contained within 0.5–1.5 fold difference. The mean absolute error and root mean square error for the developed model was 15 and 27%, respectively. Conclusion: The model may be used in a prospective manner for dosing decisions of micafungin in pediatric patients.

Effect of obesity on the pharmacokinetics of antimicrobials in critically ill patients: A structured review

The increased prevalence of obesity presents challenges for clinicians aiming to provide optimised antimicrobial dosing in the intensive care unit. Obesity is likely to exacerbate the alterations to antimicrobial pharmacokinetics when the chronic diseases associated with obesity exist with the acute pathophysiological changes associated with critical illness. The purpose of this paper is to review the potential pharmacokinetic (PK) changes of antimicrobials in obese critically ill patients and the implications for appropriate dosing. We found that hydrophilic antimicrobials (e.g. β-lactams, vancomycin, daptomycin) were more likely to manifest altered pharmacokinetics in critically ill patients who are obese. In particular for β-lactam antibiotics, obesity is associated with a larger volume of distribution (V(d)). In obese critically ill patients, piperacillin is also associated with a lower drug clearance (CL). For doripenem, these PK changes have been associated with reduced achievement of pharmacodynamic (PD) targets when standard drug doses are used. For vancomycin, increases in Vd are associated with increasing total body weight (TBW), meaning that the loading dose should be based on TBW even in obese patients. For daptomycin, an increased Vd is not considered to be clinically relevant. For antifungals, little data exist in obese critically ill patients; during fluconazole therapy, an obese patient had a lower V(d) and higher CL than non-obese comparators. Overall, most studies suggested that standard dosage regimens of most commonly used antimicrobials are sufficient to achieve PD targets. However, it is likely that larger doses would be required for pathogens with higher minimum inhibitory concentrations.

Efficacy of Extended-Interval Dosing of Micafungin Evaluated Using a Pharmacokinetic/Pharmacodynamic Study with Humanized Doses in Mice

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.

Altered Micafungin Pharmacokinetics in Intensive Care Unit Patients

Micafungin is considered an important agent for the treatment of invasive fungal infections in the intensive care unit (ICU). Little is known on the pharmacokinetics of micafungin. We investigated micafungin pharmacokinetics (PK) in ICU patients and set out to explore the parameters that influence micafungin plasma concentrations. ICU patients receiving 100 mg of intravenous micafungin once daily for suspected or proven fungal infection or as prophylaxis were eligible. Daily trough concentrations and PK curves (days 3 and 7) were collected. Pharmacokinetic analysis was performed using a standard two-stage approach. Twenty patients from the ICUs of four hospitals were evaluated. On day 3 (n = 20), the median (interquartile range [IQR]) area under the concentration-time curve from 0 to 24 h (AUC0-24) was 78.6 (65.3 to 94.1) mg · h/liter, the maximum concentration of drug in serum (Cmax) was 7.2 (5.4 to 9.2) mg/liter, the concentration 24 h after dosing (C24) was 1.55 (1.4 to 3.1) mg/liter, the volume of distribution (V) was 25.6 (21.3 to 29.1) liters, the clearance (CL) was 1.3 (1.1 to 1.5) liters/h, and the elimination half-life (t1/2) was 13.7 (12.2 to 15.5) h. The pharmacokinetic parameters on day 7 (n = 12) were not significantly different from those on day 3. Daily trough concentrations (day 3 to the end of therapy) showed moderate interindividual (57.9%) and limited intraindividual variability (12.9%). No covariates of the influence on micafungin exposure were identified. Micafungin was considered safe and well tolerated. We performed the first PK study with very intensive sampling on multiple occasions in ICU patients, which aided in resolving micafungin PK. Strikingly, micafungin exposure in our cohort of ICU patients was lower than that in healthy volunteers but not significantly different from that of other reference populations. The clinical consequence of these findings must be investigated in a pharmacokinetic-pharmacodynamic (PK-PD) study incorporating outcome in a larger cohort. (This study is registered at ClinicalTrials.gov under registration no. NCT01783379.).

Fluconazole population pharmacokinetics and dosing for prevention and treatment of invasive Candidiasis in children supported with extracorporeal membrane oxygenation

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.

Impact of special patient populations on the pharmacokinetics of echinocandins

Echinocandins belong to the class of antifungal agents. Currently, three echinocandin drugs are licensed for intravenous treatment of invasive fungal infections: anidulafungin, caspofungin and micafungin. While their antifungal activity overlaps, there are substantial differences in pharmacokinetics (PK). Numerous factors may account for variability in PK of echinocandins including age (pediatrics vs adults), body surface area and body composition (normal weight vs obesity), disease status (e.g., critically ill and burn patients) and organ dysfunction (kidney and liver impairment). Subsequent effects of altered exposure might impact efficacy and safety. Knowledge of PK behavior is crucial in optimal clinical utilization of echinocandin in a specific patient or patient population. This review provides up-to-date information on PK data of anidulafungin, caspofungin and micafungin in special patient populations. Patient populations addressed are neonates, children and adolescents, obese patients, patients with hepatic or renal impairment, critically ill patients (including burn patients) and patients with hematological diseases.

Efficacy and safety of echinocandins versus triazoles for the prophylaxis and treatment of fungal infections: a meta-analysis of RCTs

Echinocandins and triazoles were proven to be effective antifungal drugs against invasive fungal infections (IFI), which may cause significant morbidity and mortality in immunocompromised patients. The aim of this study was to compare the efficacy and safety between echinocandins and triazoles for the prophylaxis and treatment of fungal infections. PubMed, Embase, and the Cochrane Library were searched to identify relevant randomized controlled trials (RCTs) up to July 2014. The quality of trials was assessed with the Jadad scoring system. The primary outcomes of interest were treatment success, microbiological success, breakthrough infection, drug-related adverse events (AEs), withdrawals due to AEs, and all-cause mortality. Ten RCTs, involving 2,837 patients, were included, as follows: caspofungin versus fluconazole (n = 1), caspofungin versus itraconazole (n = 1), anidulafungin versus fluconazole (n = 1), micafungin versus fluconazole (n = 4), micafungin versus voriconazole (n = 2), and micafungin versus itraconazole (n = 1). Echinocandins and triazoles showed similar effects in terms of favorable treatment success rate [relative risk (RR) = 1.02, 95 % confidence interval (CI), 0.97–1.08], microbiological success rate (RR = 0.98, 95 % CI, 0.90–1.15), breakthrough infection (RR = 1.09; 95 % CI, 0.59–2.01), drug-related AEs (RR = 0.94; 95 % CI, 0.71–1.15), and all-cause mortality (RR = 0.85; 95 % CI, 0.66–1.10) in the prophylaxis and treatment of fungal infections. Additionally, echinocandins were more effective than triazoles for prophylaxis in patients undergoing hematologic malignancies or those who received hematopoietic stem cell transplantation (HSCT; RR = 1.08; 95 % CI, 1.02–1.15). Echinocandins significantly decreased the AE-related withdrawals rate compared with triazoles (RR = 0.47; 95 % CI, 0.33–0.67). This meta-analysis revealed that echinocandins are as effective and safe as triazoles for the prophylaxis and treatment of patients with fungal infections.

Different doses of micafungin for prophylaxis of invasive fungal diseases in hemato-oncological high-risk patients: a web-based non-interventional trial in four large university hospitals in Germany

INTRODUCTION

Treatment indications of new antifungals in clinical practice often deviate from the strict criteria used in controlled clinical trials. Under routine clinical conditions, beneficial and adverse effects, not previously described in clinical trials may be observed. The aim of this study was to describe customary prescription and treatment strategies of micafungin (MCFG).

METHODS

A registry was set up on www.ClinicalSurveys.net and physicians were invited to provide retrospective information on cases they had treated with MCFG. Documentation comprised demographic information, underlying disease, effectiveness, safety, and tolerability of MCFG.

RESULTS

A total of 125 episodes of patients hospitalized between September 2009 and February 2012 were documented, of which 7 had to be excluded because of incomplete documentation. The most common risk factors of patients were hematological malignancy (n = 116, 98.3%) and antibiotic treatment >3 days (n = 115, 97.5%). MCFG was administered as prophylaxis in 106 (89.9%) patients. Median duration of MCFG application as prophylaxis was 21 days (range: 3-78); 53 of the patients (50%) received a dose of 50 mg, while the other 53 (50%) received 100 mg/day. For the different doses, prophylactic outcome was rated as success in 42 (79.2%) vs. 52 (98.1%; P = 0.004) patients. Fifty-five patients (51.9%) were treated with posaconazole before initiation of MCFG. Four patients (7.5%) developed a proven invasive fungal disease (IFD) while being treated with 50 mg MCFG, compared to no patient treated with 100 mg (P = 0.118). At the end of MCFG prophylaxis, 24 (22.6%) patients were switched to fluconazole and 64 (60.3%) patients to posaconazole.

CONCLUSION

Our study shows clinical effectiveness of MCFG prophylaxis with low rates of breakthrough fungal infections. In most cases, MCFG was part of a multi-modal antifungal prophylactic strategy. Investigators reported fewer proven IFDs in patients receiving therapeutic doses of MCFG as prophylaxis.

Treatment with echinocandins during continuous renal replacement therapy

Echinocandins are indicated as first-line treatment for invasive candidiasis in moderate to severe illness. As sepsis is the main cause of acute kidney injury, the combination of echinocandin treatment and continuous renal replacement therapy (CRRT) is common. Optimizing antibiotic dosage in critically ill patients receiving CRRT is challenging. The pharmacokinetics of echinocandins have been studied under various clinical conditions; however, data for CRRT patients are scarce. Classically, drugs like echinocandins with high protein binding and predominantly non-renal elimination are not removed by CRRT, indicating that no dosage adjustment is required. However, recent studies report different proportions of echinocandins lost by filter adsorption. Nevertheless, the clinical significance of these findings remains unclear.

Systemic antifungal prophylaxis after hematopoietic stem cell transplantation: a meta-analysis

BACKGROUND

Hematopoietic stem transplant recipients are subject to increased risk for invasive fungal infections.

OBJECTIVE

This meta-analysis was undertaken to explore the comparative effectiveness of systemic antifungal prophylaxis in hematopoietic stem cell transplant recipients.

METHODS

We searched PubMed and The Cochrane Register of Randomized Controlled Trials up to March 2013 for randomized studies on systemic antifungal prophylaxis after hematopoietic stem cell transplantation. We performed a meta-analysis on the relative effectiveness of systemic antifungal prophylaxis on proven or probable invasive fungal infections using direct and indirect effects. Relative effectiveness was reported as odds ratio (OR) for invasive fungal infections, causative agent, empirical antifungal therapy, and withdrawals due to drug adverse events.

RESULTS

Twenty evaluable studies provided data on 4823 patients. The risk for invasive fungal infections while on prophylaxis was 5.1% (95% CI, 3.6-6.8%). In patients receiving fluconazole, risks of proven or probable invasive fungal infections (OR = 0.24; 95% CI, 0.11-0.50; number needed to treat [NNT] = 8), systemic candidiasis (OR = 0.11; 95% CI, 0.05-0.24; NNT = 7), and overall need for empiric antifungal treatment (OR = 0.60; 95% CI, 0.44-0.82; NNT = 8) were reduced compared with patients receiving placebo. Itraconazole was more effective than fluconazole for the prevention of aspergillosis (OR = 0.40; 95% CI, 0.19-0.83; NNT = 23) at the expense of more frequent withdrawals (OR = 3.01; 95% CI, 1.77-5.13; number needed to harm = 6). Micafungin was marginally more effective than fluconazole for the prevention of all mold infections (OR = 0.35; 95% CI, 0.10-1.18; NNT = 79) and invasive aspergillosis (OR = 0.19; 95% CI, 0.03-1.11; NNT = 78) and reducing the need for empiric antifungal treatment (OR = 0.40; 95% CI, 0.13-1.21; NNT = 8). There was a relative lack of comparisons between different antifungal prophylactic strategies, including the newer azoles, voriconazole and posaconazole, in this population. Direct effects derived from single studies showed marginally significant effects for voriconazole compared with fluconazole regarding invasive aspergillosis (OR = 0.50; 95% CI, 0.20-1.20; NNT = 35) and the need for empiric treatment (OR = 0.72; 95% CI, 0.50-1.06; NNT = 15). Voriconazole compared with itraconazole (OR = 0.59; 95% CI, 0.40-0.88; NNT = 8) and posaconazole compared with amphotericin B (OR = 0.28; 95% CI, 0.06-1.24, marginal significance; NNT = 3) were better regarding empirical antifungal treatment.

CONCLUSIONS

Even when on antifungal therapy, invasive fungal infection will develop in 1 of 20 patients undergoing hematopoietic stem cell transplantation. There is evidence for the comparable effectiveness of different antifungal drugs used for prophylaxis. Fluconazole is the most widely studied agent, but micafungin might prove to be more effective. There is a relative paucity of studies for the newer azoles, although both voriconazole and posaconazole give proof of their comparative or higher effectiveness to fluconazole in single randomized studies.

Antifungal prophylaxis among allogeneic hematopoietic stem cell transplant recipients: current issues and new agents

Invasive candidiasis and invasive mold infections cause significant morbidity and mortality in the hematopoietic stem cell transplant population, in particular in recipients of allografts. The introduction of a variety of new antifungal compounds over the past decade has focused attention on prophylactic strategies as a means to decrease the burden of invasive fungal infections (IFIs). Until recently, fluconazole has been the standard agent for prophylaxis before and after engraftment. In 2005, the echinocandin micafungin received US FDA approval for prophylaxis against IFIs in stem cell transplant recipients during the neutropenic period prior to engraftment. In patients with substantial risk for invasive mold infection, many centers now use a mold-active antifungal agent (e.g., a triazole such as itraconazole, voriconazole or posaconazole, or an echinocandin) as prophylaxis after engraftment. Several recent studies have highlighted the efficacy of these newer agents in preventing IFIs in these highly immunocompromised patients. This review will discuss current issues in IFI and new agents available for prophylaxis in allogeneic hematopoietic stem cell transplant recipients.

Iatrogenic neurology

Iatrogenic disease is one of the most frequent causes of hospital admissions and constitutes a growing public health problem. The most common type of iatrogenic neurologic disease is pharmacologic, and the central and peripheral nervous systems are particularly vulnerable. Despite this, iatrogenic disease is generally overlooked as a differential diagnosis among neurologic patients. The clinical picture of pharmacologically mediated iatrogenic neurologic disease can range from mild to fatal. Common and uncommon forms of drug toxicity are comprehensively addressed in this chapter. While the majority of neurologic adverse effects are listed and referenced in the tables, the most relevant issues are further discussed in the text.

Safety and pharmacokinetic profiles of repeated-dose micafungin in children and adolescents treated for invasive candidiasis

BACKGROUND

Micafungin is an echinocandin with proven efficacy against a broad range of fungal infections, including those caused by Candida spp.

OBJECTIVE

To evaluate the safety and pharmacokinetics of once-daily 3 mg/kg and 4.5 mg/kg micafungin in children with proven, probable or suspected invasive candidiasis.

METHODS

Micafungin safety and pharmacokinetics were assessed in 2 phase I, open-label, repeat-dose trials. In Study 2101, children aged 2-16 years were grouped by weight to receive 3 mg/kg (≥25 kg) or 4.5 mg/kg (<25 kg) intravenous micafungin for 10-14 days. In Study 2102, children aged 4 months to <2 years received 4.5 mg/kg micafungin. Study protocols were otherwise identical.

RESULTS

Safety was analyzed in 78 and 9 children in Studies 2101 and 2102, respectively. Although adverse events (AEs) were experienced by most children (2101: n=62; 2102: n=9), micafungin-related AEs were less common (2101: n=28; 2102: n=1), and the number of patients discontinuing due to AEs was low (2101: n=4; 2102: n=1). The most common micafungin-related AEs were infusion-associated symptoms, pyrexia and hypomagnesemia (Study 2101), and liver function abnormalities (Study 2102). The micafungin pharmacokinetic profile was similar to that seen in other studies conducted in children, but different than that observed in adults.

CONCLUSIONS

In this small cohort of children, once-daily doses of 3 mg/kg and 4.5 mg/kg micafungin were well tolerated. Pharmacokinetic data will be combined in a population pharmacokinetic analysis to support US dosing recommendations in children.

Newer antifungal agents for fungal infection prevention during hematopoietic cell transplantation: a meta-analysis

OBJECTIVE

The efficacy of newer antifungal agents to provide effective prophylaxis during stem cell transplantation has not yet been established. We compared the clinical outcomes using of the newer triazoles and echinocandins for antifungal prophylaxis.

METHODS

We electronically searched the databases of Cochrane Central Register of Controlled Trials, Pubmed, EMBASE, and relevant articles from 1987 through 2011. We examined comparative studies for survival, proven fungal infections, mortality, and adverse effects. Our meta-analysis was performed by Review Manager 5.1.6 software with funnel plot regression analysis to assess publication bias.

RESULTS

Among 1443 records were 17 studies including 5122 patients for analyses. Pooled comparisons of studies showed antifungal prophylaxis with the new agents to reduce the incidence of invasive fungal infections greater than fluconazole or itraconazole. A reduction in invasive fungal infections was achieved using micafungin, voriconazole, and posaconazole for antifungal prophylaxis. Posaconazole and voriconazole prophylaxis decreased transplant mortality compared with fluconazole or itraconazole prophylaxis. Voriconazole and posaconzole showed greater rates of liver dysfunction and lower incidences gastrointestinal side effects than fluconazole. Caspofungin and voriconazole treatment incurred lower rates of nephrotoxic effects than amphotericin B. Only voriconazole displayed significantly decreased adverse events requiring drug discontinuation compared with fluconazole or itraconazole.

CONCLUSIONS

This analysis indicated new antifungal agents were well-tolerated with manageable side effects. They were beneficial for prophylaxis of invasive fungal infections.