Multicenter, noncomparative study of caspofungin in combination with other antifungals as salvage therapy in adults with invasive aspergillosis

Functional analysis of the Aspergillus fumigatus kinome identifies a druggable DYRK kinase that regulates septal plugging

More than 10 million people suffer from lung diseases caused by the pathogenic fungus Aspergillus fumigatus. Azole antifungals represent first-line therapeutics for most of these infections but resistance is rising, therefore the identification of antifungal targets whose inhibition synergises with the azoles could improve therapeutic outcomes. Here, we generate a library of 111 genetically barcoded null mutants of Aspergillus fumigatus in genes encoding protein kinases, and show that loss of function of kinase YakA results in hypersensitivity to the azoles and reduced pathogenicity. YakA is an orthologue of Candida albicans Yak1, a TOR signalling pathway kinase involved in modulation of stress responsive transcriptional regulators. We show that YakA has been repurposed in A. fumigatus to regulate blocking of the septal pore upon exposure to stress. Loss of YakA function reduces the ability of A. fumigatus to penetrate solid media and to grow in mouse lung tissue. We also show that 1-ethoxycarbonyl-beta-carboline (1-ECBC), a compound previously shown to inhibit C. albicans Yak1, prevents stress-mediated septal spore blocking and synergises with the azoles to inhibit A. fumigatus growth.

Functional analysis of the Aspergillus fumigatus kinome reveals a DYRK kinase involved in septal plugging is a novel antifungal drug target

More than 10 million people suffer from lung diseases caused by the pathogenic fungus Aspergillus fumigatus. The azole class of antifungals represent first line therapeutics for most of these infections however resistance is rising. Identification of novel antifungal targets that, when inhibited, synergise with the azoles will aid the development of agents that can improve therapeutic outcomes and supress the emergence of resistance. As part of the A. fumigatus genome-wide knockout program (COFUN), we have completed the generation of a library that consists of 120 genetically barcoded null mutants in genes that encode the protein kinase cohort of A. fumigatus. We have employed a competitive fitness profiling approach (Bar-Seq), to identify targets which when deleted result in hypersensitivity to the azoles and fitness defects in a murine host. The most promising candidate from our screen is a previously uncharacterised DYRK kinase orthologous to Yak1 of Candida albicans, a TOR signalling pathway kinase involved in modulation of stress responsive transcriptional regulators. Here we show that the orthologue YakA has been repurposed in A. fumigatus to regulate blocking of the septal pore upon exposure to stress via phosphorylation of the Woronin body tethering protein Lah. Loss of YakA function reduces the ability of A. fumigatus to penetrate solid media and impacts growth in murine lung tissue. We also show that 1-ethoxycarbonyl-beta-carboline (1-ECBC), a compound previously shown to inhibit Yak1 in C. albicans prevents stress mediated septal spore blocking and synergises with the azoles to inhibit A. fumigatus growth.

Systemic Antifungal Therapy for Invasive Pulmonary Infections

Antifungal therapy for pulmonary fungal diseases is in a state of flux. Amphotericin B, the time-honored standard of care for many years, has been replaced by agents demonstrating superior efficacy and safety, including extended-spectrum triazoles and liposomal amphotericin B. Voriconazole, which became the treatment of choice for most pulmonary mold diseases, has been compared with posaconazole and itraconazole, both of which have shown clinical efficacy similar to that of voriconazole, with fewer adverse events. With the worldwide expansion of azole-resistant Aspergillus fumigatus and infections with intrinsically resistant non-Aspergillus molds, the need for newer antifungals with novel mechanisms of action becomes ever more pressing.

Therapeutic Approaches for Combating Aspergillus Associated Infection

Now-a-days fungal infection emerges as a significant problem to healthcare management systems due to high frequency of associated morbidity, mortality toxicity, drug-drug interactions, and resistance of the antifungal agents. Aspergillus is the most common mold that cause infection in immunocompromised hosts. It's a hyaline mold that is cosmopolitan and ubiquitous in nature. Aspergillus infects around 10 million population each year with a mortality rate of 30-90%. Clinically available antifungal formulations are restricted to four classes (i.e., polyene, triazole, echinocandin, and allylamine), and each of them have their own limitations associated with the activity spectrum, the emergence of resistance, and toxicity. Consequently, novel antifungal agents with modified and altered chemical structures are required to combat these invasive fungal infections. To overcome these limitations, there is an urgent need for new antifungal agents that can act as potent drugs in near future. Currently, some compounds have shown effective antifungal activity. In this review article, we have discussed all potential antifungal therapies that contain old antifungal drugs, combination therapies, and recent novel antifungal formulations, with a focus on the Aspergillus associated infections.

Efficacy and Safety of Combination Antifungals as Empirical, Preemptive, and Targeted Therapies for Invasive Fungal Infections in Intensive-Care Units

Purpose

To determine whether combinations of antifungal drugs are effective and safe for patients in intensive-care units.

Methods

This study compared the efficacy and safety of caspofungin (CAS), voriconazole (VOR), amphotericin B liposome (L-AmB), CAS+VOR, and CAS+L-AmB as empirical, preemptive, and targeted therapies for invasive fungal infection (IFI).

Results

Comparing the CAS, VOR, and CAS+VOR groups revealed that there were no differences in response rates between all therapy types, IFI-associated death within 90 days was less common in the CAS+VOR group (1.8%) than the VOR group (14.3%), and there were more adverse events in the VOR group than in the CAS group (P < 0.05). For empirical or preemptive therapy, the CAS group had a better response rate (80.0%) than the CAS+VOR group (47.1%), and there were more adverse events in the VOR group than in the CAS group (P < 0.05). For targeted therapy, no differences were found for efficacy and safety. There were no differences among the CAS, L-AmB, and CAS+L-AmB groups in efficacy and safety.

Conclusion

Patients who received CAS monotherapy as an empirical or preemptive therapy could achieve good outcomes. Patients who received CAS+VOR or CAS+L-AmB achieved almost the same outcomes when compared with those who received CAS, VOR, and L-AmB monotherapy as targeted therapies, but those who received CAS+VOR had a lower IFI mortality rate than did those who received VOR monotherapy.

When to change treatment of acute invasive aspergillosis: an expert viewpoint

Invasive aspergillosis (IA) is an acute infection affecting patients who are immunocompromised, as a result of receiving chemotherapy for malignancy, or immunosuppressant agents for transplantation or autoimmune disease. Whilst criteria exist to define the probability of infection for clinical trials, there is little evidence in the literature or clinical guidelines on when to change antifungal treatment in patients who are receiving prophylaxis or treatment for IA. To try and address this significant gap, an advisory board of experts was convened to develop criteria for the management of IA for use in designing clinical trials, which could also be used in clinical practice. For primary treatment failure, a change in antifungal therapy should be made: (i) when mycological susceptibility testing identifies an organism from a confirmed site of infection, which is resistant to the antifungal given for primary therapy, or a resistance mutation is identified by molecular testing; (ii) at, or after, 8 days of primary antifungal treatment if there is increasing serum galactomannan, or galactomannan positivity in serum, or bronchoalveolar lavage fluid when the antigen was previously undetectable, or there is sudden clinical deterioration, or a new clearly distinct site of infection is detected; and (iii) at, or after, 15 days of primary antifungal treatment if the patient is clinically stable but with ≥2 serum galactomannan measurements persistently elevated compared with baseline or increasing, or if the original lesions on CT or other imaging, show progression by >25% in size in the context of no apparent change in immune status.

Modeling Invasive Aspergillosis: How Close Are Predicted Antifungal Targets?

Animal model systems are a critical component of the process of discovery and development of new antifungal agents for treatment and prevention of invasive aspergillosis. The persistently neutropenic rabbit model of invasive pulmonary aspergillosis (IPA) has been a highly predictive system in identifying new antifungal agents for treatment and prevention of this frequently lethal infection. Since its initial development, the persistently neutropenic rabbit model of IPA has established a strong preclinical foundation for dosages, drug disposition, pharmacokinetics, safety, tolerability, and efficacy for deoxycholate amphotericin B, liposomal amphotericin B, amphotericin B lipid complex, amphotericin B colloidal dispersion, caspofungin, micafungin, anidulafungin, voriconazole, posaconazole, isavuconazole, and ibrexafungerp in treatment of patients with invasive aspergillosis. The findings of combination therapy with a mould-active triazole and an echinocandin in this rabbit model also predicted the outcome of the clinical trial for voriconazole plus anidulafungin for treatment of IPA. The plasma pharmacokinetic parameters and tissue disposition for most antifungal agents approximate those of humans in persistently neutropenic rabbits. Safety, particularly nephrotoxicity, has also been highly predictive in the rabbit model, as exemplified by the differential glomerular filtration rates observed in animals treated with deoxycholate amphotericin B, liposomal amphotericin B, amphotericin B lipid complex, and amphotericin B colloidal dispersion. A panel of validated outcome variables measures therapeutic outcome in the rabbit model: residual fungal burden, markers of organism-mediated pulmonary injury (lung weights and infarct scores), survival, and serum biomarkers. In selected antifungal studies, thoracic computerized tomography (CT) is also used with diagnostic imaging algorithms to measure therapeutic response of pulmonary infiltrates, which exhibit characteristic radiographic patterns, including nodules and halo signs. Further strengthening the predictive properties of the model, therapeutic response to successfully developed antifungal agents for treatment of IPA has been demonstrated over the past two decades by biomarkers of serum galactomannan and (1→3)-β-D-glucan with patterns of resolution, that closely mirror those documented responses in patients with IPA. The decision to move from laboratory to clinical trials should be predicated upon a portfolio of complementary and mutually validating preclinical laboratory animal models studies. Other model systems, including those in mice, rats, and guinea pigs, are also valuable tools in developing clinical protocols. Meticulous preclinical investigation of a candidate antifungal compound in a robust series of complementary laboratory animal models will optimize study design, de-risk clinical trials, and ensure tangible benefit to our most vulnerable immunocompromised patients with invasive aspergillosis.

Treatment of invasive fungal diseases in cancer patients-Revised 2019 Recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

BACKGROUND

Invasive fungal diseases remain a major cause of morbidity and mortality in cancer patients undergoing intensive cytotoxic therapy. The choice of the most appropriate antifungal treatment (AFT) depends on the fungal species suspected or identified, the patient's risk factors (eg length and depth of granulocytopenia) and the expected side effects.

OBJECTIVES

Since the last edition of recommendations for 'Treatment of invasive fungal infections in cancer patients' of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO) in 2013, treatment strategies were gradually moving away from solely empirical therapy of presumed or possible invasive fungal diseases (IFDs) towards pre-emptive therapy of probable IFD.

METHODS

The guideline was prepared by German clinical experts for infections in cancer patients in a stepwise consensus process. MEDLINE was systematically searched for English-language publications from January 1975 up to September 2019 using the key terms such as 'invasive fungal infection' and/or 'invasive fungal disease' and at least one of the following: antifungal agents, cancer, haematological malignancy, antifungal therapy, neutropenia, granulocytopenia, mycoses, aspergillosis, candidosis and mucormycosis.

RESULTS

AFT of IFDs in cancer patients may include not only antifungal agents but also non-pharmacologic treatment. In addition, the armamentarium of antifungals for treatment of IFDs has been broadened (eg licensing of isavuconazole). Additional antifungals are currently under investigation or in clinical trials.

CONCLUSIONS

Here, updated recommendations for the treatment of proven or probable IFDs are given. All recommendations including the levels of evidence are summarised in tables to give the reader rapid access to key information.

A case of invasive pulmonary aspergillosis diagnosed by transbronchial lung biopsy during treatment for diabetic ketoacidosis in a type 1 diabetic patient

Invasive pulmonary aspergillosis (IPA) patients with non-hematological malignancy are far less than with hematological malignancy patients. We encountered a very rare case of IPA in which type 1 diabetes was the only conceivable risk factor. Further, according to the diagnostic categories of the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) criteria for IPA, the frequency of proven diagnosis is very low. Here we report a proven IPA, which rapidly developed when the patient with type 1 diabetes was being treated for diabetic ketoacidosis, which was successfully treated with the combination therapy of voriconazole (VRCZ) and micafungin (MCFG), based on early diagnosis using bronchoscopy.

ESCMID-ECMM guideline: diagnosis and management of invasive aspergillosis in neonates and children

SCOPE

Presenting symptoms, distributions and patterns of diseases and vulnerability to invasive aspergillosis (IA) are similar between children and adults. However, differences exist in the epidemiology and underlying conditions, the usefulness of newer diagnostic tools, the pharmacology of antifungal agents and in the evidence from interventional phase 3 clinical trials. Therefore, the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) and the European Confederation of Medical Mycology (ECMM) have developed a paediatric-specific guideline for the diagnosis and management of IA in neonates and children.

METHODS

Review and discussion of the scientific literature and grading of the available quality of evidence was performed by the paediatric subgroup of the ESCMID-ECMM-European Respiratory Society (ERS) Aspergillus disease guideline working group, which was assigned the mandate for the development of neonatal- and paediatric-specific recommendations.

QUESTIONS

Questions addressed by the guideline included the epidemiology of IA in neonates and children; which paediatric patients may benefit from antifungal prophylaxis; how to diagnose IA in neonates and children; which antifungal agents are available for use in neonates and children; which antifungal agents are suitable for prophylaxis and treatment of IA in neonates and children; what is the role of therapeutic drug monitoring of azole antifungals; and which management strategies are suitable to be used in paediatric patients. This guideline provides recommendations for the diagnosis, prevention and treatment of IA in the paediatric population, including neonates. The aim of this guideline is to facilitate optimal management of neonates and children at risk for or diagnosed with IA.

How We Approach Combination Antifungal Therapy for Invasive Aspergillosis and Mucormycosis in Transplant Recipients

Invasive aspergillosis and mucormycosis are life-threatening infections in solid organ and hematopoietic cell transplant recipients. Despite medical advancements in the care of these patients and the availability of new mold-active drugs, the outcomes remain suboptimal. Therefore, there has been increased interest in the use of combination antifungal therapy, in hopes that leveraging the possible in vitro synergy of these agents will improve the prognosis of invasive mold disease. However, there has been a large disconnect between the results of experimental and clinical investigations, as clinical studies have not unequivocally demonstrated the superiority of combination therapy over monotherapy. This is particularly true for mucormycosis, where the rarity of the condition has made it nearly impossible to prospectively study novel therapeutic strategies. We review the current standard of antifungal therapy and the preclinical and clinical data addressing the merit of combination therapy, and we provide guidance to optimize the management of these mycoses.

Invasive Aspergillosis in Children: Update on Current Guidelines

Invasive aspergillosis (IA) is an important cause of infectious morbidity and mortality in immunocompromised paediatric patients. Despite improvements in diagnosis, prevention, and treatment, IA is still associated with high mortality rates. To address this issue, several international societies and organisations have proposed guidelines for the management of IA in the paediatric population. In this article, we review current recommendations of the Infectious Diseases Society of America, the European Conference on Infection in Leukaemia and the European Society of Clinical Microbiology and Infectious Diseases for the management and prevention of IA in children.

Treatment of Aspergillosis

Infections caused by Aspergillus spp. remain associated with high morbidity and mortality. While mold-active antifungal prophylaxis has led to a decrease of occurrence of invasive aspergillosis (IA) in those patients most at risk for infection, breakthrough IA does occur and remains difficult to diagnose due to low sensitivities of mycological tests for IA. IA is also increasingly observed in other non-neutropenic patient groups, where clinical presentation is atypical and diagnosis remains challenging. Early and targeted systemic antifungal treatment remains the most important predictive factor for a successful outcome in immunocompromised individuals. Recent guidelines recommend voriconazole and/or isavuconazole for the primary treatment of IA, with liposomal amphotericin B being the first alternative, and posaconazole, as well as echinocandins, primarily recommended for salvage treatment. Few studies have evaluated treatment options for chronic pulmonary aspergillosis (CPA), where long-term oral itraconazole or voriconazole remain the treatment of choice.

The spectrum of pulmonary aspergillosis

Notable progress has been made in the past years in the classification, diagnosis and treatment of pulmonary aspergillosis. New criteria were proposed by the Working Group of the International Society for Human and Animal Mycology (ISHAM) for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA). The latest classification of chronic pulmonary aspergillosis (CPA) suggested by the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) has become widely accepted among clinicians. Subacute invasive pulmonary aspergillosis is now considered a type of CPA, yet it is still diagnosed and treated similarly to invasive pulmonary aspergillosis (IPA). Isavuconazole, an extended-spectrum triazole, has recently been approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of IPA. The most recent Infectious Diseases Society of America (IDSA) guidelines strongly recommend reducing mold exposure to patients at high risk for pulmonary aspergillosis. The excessive relapse rate following discontinuation of therapy remains a common reality to all forms of this semi-continuous spectrum of diseases. This highlights the need to continuously reassess patients and individualize therapy accordingly. Thus far, the duration of therapy and the frequency of follow-up have to be well characterized.

Lipid Biosynthesis as an Antifungal Target

Lipids, commonly including phospholipids, sphingolipids, fatty acids, sterols, and triacylglycerols (TAGs), are important biomolecules for the viability of all cells. Phospholipids, sphingolipids, and sterols are important constituents of biological membranes. Many lipids play important roles in the regulation of cell metabolism by acting as signaling molecules. Neutral lipids, including TAGs and sterol esters (STEs), are important storage lipids in cells. In view of the importance of lipid molecules, this review briefly summarizes the metabolic pathways for sterols, phospholipids, sphingolipids, fatty acids, and neutral lipids in fungi and illustrates the differences between fungal and human (or other mammalian) cells, especially in relation to lipid biosynthetic pathways. These differences might provide valuable clues for us to find target proteins for novel antifungal drugs. In addition, the development of lipidomics technology in recent years has supplied us with a shortcut for finding new antifungal drug targets; this ability is important for guiding our research on pathogenic fungi.

Combination therapy for the treatment of pulmonary mold infections

INTRODUCTION

Pulmonary mold infections are caused by ubiquitous organisms found in soil, water, and decaying vegetation, including Aspergillus spp., the Mucormycetes, hyaline molds, and dematiaceous (black) molds. Areas covered: These infections are often a challenge to diagnose and even more difficult to treat. Recently, antifungal combination therapy has emerged as a promising strategy to treat some forms of invasive mycoses, including pulmonary mold infections. Historically, this approach has been limited due to non-uniform interpretation criteria, variations in pharmacodynamic/pharmacokinetic properties of antifungals used in combination, and an inability to predict clinical success based on in vitro data and animal models. However, recent advances have helped mitigate some of these challenges. Expert commentary: In this paper, we explore what is known about the antifungal combination therapy in the treatment of pulmonary mold infections and explore how it may impact clinical practice. We pay particular attention to novel combinations and the challenges associated with the development of new antifungal agents.

Low Caspofungin Exposure in Patients in Intensive Care Units

In critically ill patients, drug exposure may be influenced by altered drug distribution and clearance. Earlier studies showed that the variability in caspofungin exposure was high in intensive care unit (ICU) patients. The primary objective of this study was to determine if the standard dose of caspofungin resulted in adequate exposure in critically ill patients. A multicenter prospective study in ICU patients with (suspected) invasive candidiasis was conducted in the Netherlands from November 2013 to October 2015. Patients received standard caspofungin treatment, and the exposure was determined on day 3 of treatment. An area under the concentration-time curve from 0 to 24 h (AUC_0-24) of 98 mg · h/liter was considered adequate exposure. In case of low exposure (i.e., <79 mg · h/liter, a ≥20% lower AUC_0-24), the caspofungin dose was increased and the exposure reevaluated. Twenty patients were included in the study, of whom 5 had a positive blood culture. The median caspofungin AUC_0-24 at day 3 was 78 mg · h/liter (interquartile range [IQR], 69 to 97 mg · h/liter). A low AUC_0-24 (<79 mg · h/liter) was seen in 10 patients. The AUC_0-24 was significantly and positively correlated with the caspofungin dose in mg/kg/day (P = 0.011). The median AUC_0-24 with a caspofungin dose of 1 mg/kg was estimated using a pharmacokinetic model and was 114.9 mg · h/liter (IQR, 103.2 to 143.5 mg · h/liter). In conclusion, the caspofungin exposure in ICU patients in this study was low compared with that in healthy volunteers and other (non)critically ill patients, most likely due to a larger volume of distribution. A weight-based dose regimen is probably more suitable for patients with substantially altered drug distribution. (This study has been registered at ClinicalTrials.gov under registration no. NCT01994096.).

Practice Guidelines for the Diagnosis and Management of Aspergillosis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Treatment of Disseminated Aspergillosis with Posaconazole in 10 Dogs

Background

Few effective treatments for disseminated Aspergillus infections in dogs are available. Posaconazole has potent and broad‐spectrum activity against Aspergillus spp., but its use has not yet been sufficiently evaluated in dogs.

Hypothesis/Objectives

The aim of this study was to determine the safety and efficacy of posaconazole for the treatment of naturally occurring disseminated Aspergillus infections in dogs.

Animals

Ten client‐owned dogs with disseminated aspergillosis.

Methods

Prospective, nonrandomized, noncontrolled study with posaconazole administered to dogs at dosage of 5 mg/kg PO q12h. The primary veterinarian or the veterinary specialist caring for the dogs provided patient data.

Results

The treatment response for dogs with disseminated disease while receiving posaconazole was defined as clinical remission (n = 4) and clinical improvement (n = 6). There was a high rate of relapse during treatment or after cessation of treatment in both groups, and most dogs died or were euthanized due to progressive disease. Excluding 1 dog concurrently treated with terbinafine that remains alive 5 years after diagnosis, the mean survival time for dogs was 241 days (range 44–516 days). Three other dogs lived >1 year after starting treatment. No clinically relevant adverse events or increases in serum liver enzyme activity occurred during treatment with posaconazole.

Conclusions and Clinical Importance

Posaconazole appears to be safe and well‐tolerated for treatment of disseminated Aspergillus infections in dogs. Long‐term survival >1 year is possible with prolonged treatment, but relapse is common.

In Vivo Synergy of Amphotericin B plus Posaconazole in Murine Aspergillosis

Aspergillus fumigatus is the main mold causing invasive fungal infection that shows high mortality rates. Therapeutic failure and the increase in drug resistance make it necessary to explore alternative treatments for this infection. We have evaluated the efficacy of amphotericin B at 0.8 mg/kg or 0.3 mg/kg of body weight combined with 40 mg/kg of posaconazole against three A. fumigatus isolates in a murine model of disseminated infection. The combination of the polyene and the azole led to a greater increase in survival and a significantly greater reduction in tissue burden than monotherapies.

Caspofungin: Pharmacodynamics, pharmacokinetics, clinical uses and treatment outcomes

Over the past decade, echinocandins have emerged as first-line antifungal agents for many Candida infections. The echinocandins have a unique mechanism of action, inhibiting the synthesis of β-1,3-d-glucan polymers, key components of the cell wall in pathogenic fungi. Caspofungin was the first echinocandin antifungal agent to become licensed for use. The objectives of this review are to summarize the existing published data on caspofungin, under the subject headings of chemistry and mechanism of action, spectrum of activity, pharmacodynamics, pharmacokinetics, clinical studies, safety, drug interactions, dosing, and an overview of the drug's current place in therapy.

Clinical experience of the use of voriconazole, caspofungin or the combination in primary and salvage therapy of invasive aspergillosis in haematological malignancies

Invasive aspergillosis (IA) is a life-threatening infection in severely immunocompromised haematological malignancy patients. In this study, the efficacy and safety of caspofungin, voriconazole or the combination as primary and salvage therapy in patients with IA were compared. The study included 181 patients with haematological malignancies and IA who received primary or salvage therapy with caspofungin, voriconazole or the combination. In total, 138 patients who received treatment for ≥7 days were analysed; 86 underwent primary antifungal therapy (15 with caspofungin, 38 with voriconazole and 33 with both). Among the salvage therapy patients, 17 received caspofungin, 24 received voriconazole and 35 received both. In the primary therapy group, no difference in therapy response was found, but caspofungin was associated with higher IA mortality rates. A multivariate competing risk analysis of primary antifungal therapy revealed that voriconazole was independently associated with lower IA-associated mortality rates than caspofungin (hazard ratio=0.2, 95% confidence interval 0.06-0.96; P=0.04). In the salvage therapy group, the three treatment groups had similar responses and IA-associated mortality rates. The combination of voriconazole and caspofungin did not result in better outcomes compared with voriconazole alone, as primary or salvage therapy, in haematological malignancy patients. However, voriconazole was associated with a lower Aspergillus-associated mortality rate compared with caspofungin monotherapy.

Salvage combination antifungal therapy for acute invasive aspergillosis may improve outcomes: a systematic review and meta-analysis

OBJECTIVE

A meta-analysis was performed to compare mold-active triazoles or lipid amphotericin B plus an echinocandin to non-echinocandin monotherapy for acute invasive aspergillosis (IA).

METHODS

We searched PubMed, EMBASE, and other databases through May 2013 unrestricted by language. We included observational and experimental studies wherein patients with proven or probable IA by EORTC/MSG criteria underwent our comparative intervention. PRISMA and MOOSE guidelines were followed and quality was assessed using the Jadad and Newcastle-Ottawa criteria. Meta-regression with fixed and random effects and sensitivity analyses were performed. The primary study outcome measure was 12-week overall mortality. The secondary outcome assessed was complete and partial response.

RESULTS

Only observational studies of primary 12-week survival showed heterogeneity (I(2)=48.96%, p=0.05). For salvage IA therapy, fixed effects models demonstrated improved 12-week survival (Peto odds ratio (OR) 1.80, 95% confidence interval (CI) 1.08-3.01) and success (Peto OR 2.17, 95% CI 1.21-3.91) of combination therapy. Significance remained after applying random effects as a sensitivity analysis (12-week survival: Peto OR 1.90, 95% CI 1.04-3.46, and unchanged value for success). Restriction to high quality studies and including echinocandins as the comparator for refractory IA revealed an adjusted OR of 1.72 (95% CI 0.96-3.09; p=0.07) for global success, while the survival endpoint remained unaltered.

CONCLUSIONS

Combination antifungals for IA demonstrate improved outcomes over monotherapy in the salvage setting. Clinicians should consider this approach in certain situations.

Trailing or paradoxical growth of Aspergillus flavus exposed to caspofungin is independent of genotype

There are limited data on in vitro susceptibility testing of echinocandins against Aspergillus species. The objective of this study was to describe the phenotypes of Aspergillus flavus observed on exposure to caspofungin in vitro and to test whether these phenotypes were associated with A. flavus genotypes. The caspofungin MICs of 37 A. flavus clinical isolates collected from 14 patients with invasive aspergillosis were determined using Etest assays. Caspofungin MICs ranged from 0.012 to 0.064 mg l(-1); the modal MIC was 0.023 mg l(-1) and the MIC₅₀ and MIC₉₀ were 0.032 and 0.064 mg l(-1), respectively. A clear end point was noted in 24 (65 %) isolates, whereas seven (19 %) displayed a trailing effect and six (16 %) showed paradoxical growth when exposed to caspofungin. In these A. flavus isolates, the absence of a significant population structure or genetic differentiation indicated that trailing or paradoxical growth phenotypes were independent of microsatellite genotype.

Fourth European Conference on Infections in Leukaemia (ECIL-4): guidelines for diagnosis, prevention, and treatment of invasive fungal diseases in paediatric patients with cancer or allogeneic haemopoietic stem-cell transplantation

Invasive opportunistic fungal diseases (IFDs) are important causes of morbidity and mortality in paediatric patients with cancer and those who have had an allogeneic haemopoietic stem-cell transplantation (HSCT). Apart from differences in underlying disorders and comorbidities relative to those of adults, IFDs in infants, children, and adolescents are unique with respect to their epidemiology, the usefulness of diagnostic methods, the pharmacology and dosing of antifungal agents, and the absence of interventional phase 3 clinical trials for guidance of evidence-based decisions. To better define the state of knowledge on IFDs in paediatric patients with cancer and allogeneic HSCT and to improve IFD diagnosis, prevention, and management, the Fourth European Conference on Infections in Leukaemia (ECIL-4) in 2011 convened a group that reviewed the scientific literature on IFDs and graded the available quality of evidence according to the Infectious Diseases Society of America grading system. The final considerations and recommendations of the group are summarised in this manuscript.

Anidulafungin: advantage for the newcomer?

Anidulafungin is the most recently approved compound of the echinocandin antifungal class. Its mode of action is the noncompetitive inhibition of β-(1,3)-D-glucan synthesis. Potent fungicidal activity has been demonstrated against many Candida spp., including non-albicansCandida spp. and fluconazole-resistant strains, as well as fungistatic activity against Aspergillus spp. Owing to low oral bioavailability, it can only be administered intravenously. Anidulafungin is not metabolized by the liver and renal clearance is negligible, thus rendering dosage adjustments in patients with impaired hepatic or renal function unnecessary. Due to lack of interference with the cytochrome P450 pathway, it displays minimal drug-drug interaction. Anidulafungin has been approved by the US FDA for the treatment of esophageal and invasive candidiasis after clinical trials demonstrated its noninferiority to fluconazole. In September 2007, anidulafungin gained EMEA approval for the treatment of invasive candidiasis in adult non-neutropenic patients. For those with invasive or noninvasive candidiasis with resistance or intolerance to fluconazole in particular, as well as those requiring antifungal medication, that anidulafungin does not interact with concomitant medication means it may be regarded as a safe and efficacious treatment option. Promising results from animal models and experience with the other echinocandins indicate several potential lines of investigation: invasive aspergillosis, prophylaxis and treatment of transplant patients, and empirical treatment in patients with febrile neutropenia. Significant differences in clinical efficacy or safety favoring anidulafungin over the other echinocandins are yet to be discovered.

Multicentre surveillance study on feasibility, safety and efficacy of antifungal combination therapy for proven or probable invasive fungal diseases in haematological patients: the SEIFEM real-life combo study

This multicentre observational study evaluated the feasibility, efficacy and toxicity of antifungal combination therapy (combo) as treatment of proven or probable invasive fungal diseases (IFDs) in patients with haematological malignancies. Between January 2005 and January 2010, 84 cases of IFDs (39 proven and 45 probable) treated with combo were collected in 20 Hematological Italian Centres, in patients who underwent chemotherapy or allogeneic haematopoietic stem cell transplantation for haematological diseases. Median age of patients was 34 years (range 1-73) and 37% had less than 18 years. Acute leukaemia was the most common underlying haematological disease (68/84; 81%). The phase of treatment was as follows: first induction in 21/84 (25%), consolidation phase in 18/84 (21%) and reinduction/salvage in 45/84 (54%). The main site of infection was lung with or without other sites. The principal fungal pathogens were as follows: Aspergillus sp. 68 cases (81%), Candida sp. six cases (8%), Zygomycetes four cases (5%) and Fusarium sp. four cases (5%). The most used combo was caspofungin+voriconazole 35/84 (42%), caspofungin + liposomal amphotericin B (L-AmB) 20/84 (24%) and L-AmB+voriconazole 15/84 (18%). The median duration of combo was 19 days (range 3-180). The overall response rate (ORR) was 73% (61/84 responders) without significant differences between the combo regimens. The most important factor that significantly influenced the response was granulocyte (PMN) recovery (P 0.009). Only one patient discontinued therapy (voriconazole-related neurotoxicity) and 22% experienced mild and reversible adverse events (hypokalaemia, ALT/AST increase and creatinine increase). The IFDs-attributable mortality was 17%. This study indicates that combo was both well tolerated and effective in haematological patients. The most used combo regimens were caspofungin + voriconazole (ORR 80%) and caspofungin + L-AmB (ORR 70%). The ORR was 73% and the mortality IFD related was 17%. PMN recovery during combo predicts a favourable outcome.

CLINICAL TRIALS REGISTRATION

NCT00906633.

Impact of in vivo triazole and echinocandin combination therapy for invasive pulmonary aspergillosis: enhanced efficacy against Cyp51 mutant isolates

Previous studies examining combination therapy for invasive pulmonary aspergillosis (IPA) have revealed conflicting results, including antagonism, indifference, and enhanced effects. The most commonly employed combination for this infection includes a mold-active triazole and echinocandin. Few studies have evaluated combination therapy from a pharmacodynamic (PD) perspective, and even fewer have examined combination therapy against both wild-type and azole-resistant Cyp51 mutant isolates. The current studies aim to fill this gap in knowledge. Four Aspergillus fumigatus isolates were utilized, including a wild-type strain, an Fks1 mutant (posaconazole susceptible and caspofungin resistant), and two Cyp51 mutants (posaconazole resistant). A neutropenic murine model of IPA was used for the treatment studies. The dosing design included monotherapy with posaconazole, monotherapy with caspofungin, and combination therapy with both. Efficacy was determined using quantitative PCR, and results were normalized to known quantities of conidia (conidial equivalents [CE]). The static dose, 1-log kill dose, and associated PD target area under the curve (AUC)/MIC ratio were determined for monotherapy and combination therapy. Monotherapy experiments revealed potent activity for posaconazole, with reductions of 3 to 4 log10 Aspergillus CE/ml with the two "low"-MIC isolates. Posaconazole alone was less effective for the two isolates with higher MICs. Caspofungin monotherapy did not produce a significant decrease in fungal burden for any strain. Combination therapy with the two antifungals did not enhance efficacy for the two posaconazole-susceptible isolates. However, the drug combination produced synergistic activity against both posaconazole-resistant isolates. Specifically, the combination resulted in a 1- to 2-log10 decline in burden that would not have been predicted based on the monotherapy results for each drug. This corresponded to a reduction in the free-drug posaconazole AUC/MIC ratio needed for stasis of up to 17-fold. The data suggest that combination therapy using a triazole and an echinocandin may be a beneficial treatment strategy for triazole-resistant isolates.

Treatment of invasive fungal infections in cancer patients-updated recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

The Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO) here presents its updated recommendations for the treatment of documented fungal infections. Invasive fungal infections are a main cause of morbidity and mortality in cancer patients undergoing intensive chemotherapy regimens. In recent years, new antifungal agents have been licensed, and agents already approved have been studied in new indications. The choice of the most appropriate antifungal treatment depends on the fungal species suspected or identified, the patient's risk factors (e.g., length and depth of neutropenia), and the expected side effects. This guideline reviews the clinical studies that served as a basis for the following recommendations. All recommendations including the levels of evidence are summarized in tables to give the reader rapid access to the information.

Cell wall perturbation sensitizes fungi to the antimalarial drug chloroquine

Chloroquine (CQ) has been a mainstay of antimalarial drug treatment for several decades. Additional therapeutic actions of CQ have been described, including some reports of fungal inhibition. Here we investigated the action of CQ in fungi, including the yeast model Saccharomyces cerevisiae. A genomewide yeast deletion strain collection was screened against CQ, revealing that bck1Δ and slt2Δ mutants of the cell wall integrity pathway are CQ hypersensitive. This phenotype was rescued with sorbitol, consistent with cell wall involvement. The cell wall-targeting agent caffeine caused hypersensitivity to CQ, as did cell wall perturbation by sonication. The phenotypes were not caused by CQ-induced changes to cell wall components. Instead, CQ accumulated to higher levels in cells with perturbed cell walls: CQ uptake was 2- to 3-fold greater in bck1Δ and slt2Δ mutants than in wild-type yeast. CQ toxicity was synergistic with that of the major cell wall-targeting antifungal drug, caspofungin. The MIC of caspofungin against the yeast pathogen Candida albicans was decreased 2-fold by 250 μM CQ and up to 8-fold at higher CQ concentrations. Similar effects were seen in Candida glabrata and Aspergillus fumigatus. The results show that the cell wall is critical for CQ resistance in fungi and suggest that combination treatments with cell wall-targeting drugs could have potential for antifungal treatment.

Invasive candidiasis: update on current pharmacotherapy options and future perspectives

INTRODUCTION

Invasive candidiasis (IC), mainly candidemia, is a leading cause of morbidity and mortality among immunocompromised patients and those admitted to intensive care units. Despite the recognition of risk factors and advances in disease prevention, Candida-related hospitalizations and mortality continue to rise. For treatment, four classes of older and newer antifungal agents are currently available. Adjunctive immunotherapies and a monoclonal antibody against heat shock protein 90 (efungumab) are promising novel therapeutic approaches.

AREAS COVERED

In this article, approaches and therapeutic agents for candidemia and other forms of IC are reviewed.

EXPERT OPINION

The thorough understanding of the available antifungal agents in combination with the increasing knowledge of the mechanisms that underlie the pathogenesis of Candida infections and the development of newer approaches such as efungumab and immunotherapy with adjunctive cytokines may improve the prognosis of patients with life-threatening invasive Candida infections.

The antifungal occidiofungin triggers an apoptotic mechanism of cell death in yeast

Occidiofungin is a nonribosomally synthesized cyclic peptide having a base mass of 1200 Da. It is naturally produced by the soil bacterium Burkholderia contaminans MS14 and possesses potent broad-spectrum antifungal properties. The mechanism of action of occidiofungin is unknown. Viability, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), reactive oxygen species (ROS) detection, membrane and cell wall stability, and membrane mimetic assays were used to characterize the effect of occidiofungin on yeast cells. Confocal and electron microscopy experiments were used to visualize morphological changes within treated cells. TUNEL and ROS detection assays revealed an increase in fluorescence with increasing concentrations of the antifungal. Yeast cells appeared to shrink in size and showed the presence of 'dancing bodies' at low drug concentrations (1 μg/mL). A screen carried out on Saccharomyces cerevisiae gene deletion mutants in the apoptotic and autophagy pathways identified the apoptotic gene for YCA1, as having an important role in occidiofungin response as cells deleted for this gene exhibit a 2-fold increase in resistance. Results from our experiments demonstrate that the mechanism of action for occidiofungin in yeast is different from that of the common classes of antifungals used in the clinic, such as azoles, polyenes, and echinocandins. Our study also indicates that occidiofungin causes cell death in yeast through an apoptotic mechanism of action.

Population pharmacokinetics of escalating doses of caspofungin in a phase II study of patients with invasive aspergillosis

Caspofungin (CAS) is approved for second-line management of proven or probable invasive aspergillosis at a dose of 50 mg once daily (QD). Preclinical and limited clinical data support the concept of the dose-dependent antifungal efficacy of CAS with preservation of its favorable safety profile. Little is known, however, about the pharmacokinetics (PKs) of higher doses of CAS in patients. In a formal multicenter phase II dose-escalation study, CAS was administered as a 2-h infusion at doses ranging from 70 to 200 mg QD. CAS PK sampling (n = 468 samples) was performed on day 1 and at peak and trough time points on days 4, 7, 14, and 28 (70 mg, n = 9 patients; 100 mg, n = 8 patients; 150 mg, n = 9 patients; 200 mg, n = 20 patients; total, n = 46 patients). Drug concentrations in plasma were measured by liquid chromatography tandem mass spectroscopy. Population pharmacokinetic analysis (PopPK) was performed using NONMEM (version 7) software. Model evaluation was performed using bootstrap analysis, prediction-corrected visual predictive check (pcVPC), as well as standardized visual predictive check (SVPC). The four investigated dose levels showed no difference in log-transformed dose-normalized trough levels of CAS (analysis of variance). CAS concentration data fitted best to a two-compartment model with a proportional-error model, interindividual variability (IIV) fitted best on clearance (CL), central and peripheral volume of distribution (V(1) and V(2), respectively) covariance fitted best on CL and V(1), interoccasion variability (IOV) fitted best on CL, and body weight fitted best as a covariate on CL and V(1) (CL, 0.411 liters/h ± 29% IIV; IOV on CL, 16%; V(1), 5.785 liters ± 29% IIV; intercompartmental clearance, 0.843 liters/h; V2, 6.53 liters ± 67% IIV). None of the other examined covariates (dose level, gender, age, serum bilirubin concentration, creatinine clearance) improved the model further. Bootstrap results showed the robustness of the final PopPK model. pcVPC and SVPC showed the predictability of the model and further confirmed the linear PKs of CAS over the dosage range of 70 to 200 mg QD. On the basis of the final model, geometric mean simulated peak plasma levels at steady state ranged from 13.8 to 39.4 mg/liter (geometric coefficient of variation, 31%), geometric mean trough levels ranged from 4.2 to 12.0 mg/liter (49%), and geometric mean areas under the concentration-time curves ranged from 170 to 487 mg · h/liter (34%) for the dosage range of 70 to 200 mg QD. CAS showed linear PKs across the investigated dosage range of 70 to 200 mg QD. Drug exposure in the present study population was comparable to that in other populations. (This study has been registered with the European Union Drug Regulating Authorities Clinical Trials website under registration no. 2006-001936-30 and at ClinicalTrials.gov under registration no. NCT00404092.).

Evaluation and Management of Bacterial and Fungal Infections Occurring in Patients with a Hematological Malignancy: A 2011 Update

Patients with a hematological malignancy are a heterogeneous patient population who are afflicted with diseases that range from rapidly fatal acute leukemia to indolent lymphoma or chronic leukemia. Treatment options for these patients range from observation to hematopoietic stem cell transplantation (HSCT), but all patients are more susceptible to infection. The problem of infection is dynamic with continued shifts in pathogenic organisms and microbial susceptibilities, new treatment regimens that further diminish immune function, and patients receiving treatment who are now older and frailer. The classic patterns of immunodeficiency for patients with a hematological malignancy include: periods of profound neutropenia, increased iatrogenic risks (i.e., central vascular catheters), and cellular immune suppression that affects HSCT recipients, patients with lymphoid malignancies, and those receiving treatment with corticosteroids or agents like alemtuzumab [1–4]. Recent advances in antimicrobial drug development, new technology, clinical trial results, and further clinical experience have enhanced the database on which to make infection prophylaxis and treatment decisions. However, the practicing clinician must remember that the majority of basic infection management principles for patients who are neutropenic remain unchanged.