Clinical pharmacology of antifungal compounds

Population pharmacokinetics and covariate-based dosing individualization of voriconazole in lung transplant recipients

This study aimed to explore pharmacokinetics of voriconazole and its covariates in lung transplant recipients using population approach in order to propose dosing individualization. Data from routine therapeutic drug monitoring in adult lung transplant recipients treated with oral voriconazole were analysed with a three-stage population pharmacokinetic model using nonlinear mixed-effects modelling. Monte Carlo simulations based on final voriconazole pharmacokinetic model were used to generate the theoretical distribution of pharmacokinetic profiles at various dosing regimens. A total of 78 voriconazole serum concentrations collected from 40 patients were included in pharmacokinetic analysis. The only significant covariate was age for voriconazole clearance. Population voriconazole apparent clearance started at 32.26 L/h and decreased by 0.021 L/h with each year of patient's age, while population apparent volume of distribution was 964.46 L. Based on this model, we have proposed an easy-to-use dosing regimen consisting of a loading dose of 400 mg every 12 h for the first 48 h of treatment followed by maintenance dose of 300 mg every 12 h in patients aged up to 59 years, or by maintenance dose of 200 mg every 12 h in patients aged above 59 years.

Mucorales and Mucormycosis: Recent Insights and Future Prospects

The classification of Mucorales encompasses a collection of basal fungi that have traditionally demonstrated an aversion to modern genetic manipulation techniques. This aversion led to a scarcity of knowledge regarding their biology compared to other fungal groups. However, the emergence of mucormycosis, a fungal disease caused by Mucorales, has attracted the attention of the clinical field, mainly because available therapies are ineffective for decreasing the fatal outcome associated with the disease. This revitalized curiosity about Mucorales and mucormycosis, also encouraged by the recent COVID-19 pandemic, has spurred a significant and productive effort to uncover their mysteries in recent years. Here, we elaborate on the most remarkable breakthroughs related to the recently discovered genetic advances in Mucorales and mucormycosis. The utilization of a few genetic study models has enabled the identification of virulence factors in Mucorales that were previously described in other pathogens. More notably, recent investigations have identified novel genes and mechanisms controlling the pathogenic potential of Mucorales and their interactions with the host, providing fresh avenues to devise new strategies against mucormycosis. Finally, new study models are allowing virulence studies that were previously hampered in Mucorales, predicting a prolific future for the field.

Antifungal agents and the kidney: pharmacokinetics, clinical nephrotoxicity, and interactions

INTRODUCTION

Invasive fungal infections continue to be important causes of morbidity and mortality in severely ill and immunocompromised patient populations. The past three decades have seen a considerable expansion in antifungal drug research, resulting in the clinical development of different classes of antifungal agents with different pharmacologic properties. Among drug-specific characteristics of antifungal agents, renal disposition and nephrotoxicity are important clinical considerations as many patients requiring antifungal therapy have compromised organ functions or are receiving other potentially nephrotoxic medications.

AREAS COVERED

The present article reviews incidence, severity and mechanisms of nephrotoxicity associated with antifungal agents used for prevention and treatment of invasive fungal diseases by discussing distribution, metabolism, elimination and drug-related adverse events in the context of safety data from phase II and III clinical studies.

EXPERT OPINION

Based on the available data amphotericin B deoxycholate has the highest relative potential for nephrotoxicity, followed by the lipid formulations of amphotericin B, and, to a much lesser extent and by indirect mechanisms, the antifungal triazoles.

Genes, Pathways, and Mechanisms Involved in the Virulence of Mucorales

The order Mucorales is a group of ancient fungi with limited tools for gene manipulation. The main consequence of this manipulation unwillingness is the limited knowledge about its biology compared to other fungal groups. However, the emerging of mucormycosis, a fungal infection caused by Mucorales, is attracting the medical spotlight in recent years because the treatments available are not efficient in reducing the high mortality associated with this disease. The result of this renewed interest in Mucorales and mucormycosis is an extraordinarily productive effort to unveil their secrets during the last decade. In this review, we describe the most compelling advances related to the genetic study of virulence factors, pathways, and molecular mechanisms developed in these years. The use of a few genetic study models has allowed the characterization of virulence factors in Mucorales that were previously described in other pathogens, such as the uptake iron systems, the mechanisms of dimorphism, and azole resistances. More importantly, recent studies are identifying new genes and mechanisms controlling the pathogenic potential of Mucorales and their interactions with the host, offering new alternatives to develop specific strategies against mucormycosis.

Hepatotoxicity Due to Azole Antimycotic Agents in a HLA B*35:02-Positive Patient

We will present a 42-year-old woman with acute myeloid leukemia and pulmonary aspergillosis. She was treated with several antifungal agents, including three triazoles. Voriconazole, posaconazole, and isavuconazole all led to hepatocellular liver injury. Voriconazole administration led to a peak alanine aminotransferase (ALT) value of 1,793 U/L (normal range, 9–59 U/L). After posaconazole and isavuconazole treatment, ALT rose over 500 U/L. The typical course of events, exclusion of differential diagnoses, and normalization of the liver function tests (LFTs) after stopping the triazoles were highly suspicious for a drug-induced liver injury (DILI). Interestingly, our patient carries a rare HLA B allele (HLA B*35:02), which occurs in less than 1% of the population and is known to be associated with minocycline-induced liver injury. Over the course of 4 months, the patient received two induction chemotherapies and afterward underwent a successful allogenic hematopoietic stem cell transplantation. Her liver function recovered rapidly and favorable clinical findings concerning the aspergillosis led to a de-escalation of the antifungal treatment to prophylactic dose fluconazole. Delayed hepatotoxicity suggested a dose dependency and a cumulative effect. The question of a common pathophysiology and a cross-toxicity was raised. At the present time, only a few case reports describe cross-toxicity or its absence after rechallenge with different azoles. The pathophysiology is not well understood. Ketoconazole was found to impair rat mitochondrial function in vitro. Further investigations showed cell membrane toxicity and ATP depletion in isolated human liver cancer cells. Our case report suggests a cross-toxicity, dose-dependency, and a possible genetic predisposition of triazole-induced liver injury.

Clinical Pharmacokinetics, Pharmacodynamics, Safety and Efficacy of Liposomal Amphotericin B

Since its introduction in the 1990s, liposomal amphotericin B (LAmB) continues to be an important agent for the treatment of invasive fungal diseases caused by a wide variety of yeasts and molds. This liposomal formulation was developed to improve the tolerability of intravenous amphotericin B, while optimizing its clinical efficacy. Since then, numerous clinical studies have been conducted, collecting a comprehensive body of evidence on its efficacy, safety, and tolerability in the preclinical and clinical setting. Nevertheless, insights into the pharmacokinetics and pharmacodynamics of LAmB continue to evolve and can be utilized to develop strategies that optimize efficacy while maintaining the compound's safety. In this article, we review the clinical pharmacokinetics, pharmacodynamics, safety, and efficacy of LAmB in a wide variety of patient populations and in different indications, and provide an assessment of areas with a need for further clinical research.

Candida Infections and Therapeutic Strategies: Mechanisms of Action for Traditional and Alternative Agents

The Candida genus comprises opportunistic fungi that can become pathogenic when the immune system of the host fails. Candida albicans is the most important and prevalent species. Polyenes, fluoropyrimidines, echinocandins, and azoles are used as commercial antifungal agents to treat candidiasis. However, the presence of intrinsic and developed resistance against azole antifungals has been extensively documented among several Candida species. The advent of original and re-emergence of classical fungal diseases have occurred as a consequence of the development of the antifungal resistance phenomenon. In this way, the development of new satisfactory therapy for fungal diseases persists as a major challenge of present-day medicine. The design of original drugs from traditional medicines provides new promises in the modern clinic. The urgent need includes the development of alternative drugs that are more efficient and tolerant than those traditional already in use. The identification of new substances with potential antifungal effect at low concentrations or in combination is also a possibility. The present review briefly examines the infections caused by Candida species and focuses on the mechanisms of action associated with the traditional agents used to treat those infections, as well as the current understanding of the molecular basis of resistance development in these fungal species. In addition, this review describes some of the promising alternative molecules and/or substances that could be used as anticandidal agents, their mechanisms of action, and their use in combination with traditional drugs.

Antifungal Therapy for Systemic Mycosis and the Nanobiotechnology Era: Improving Efficacy, Biodistribution and Toxicity

Fungal diseases have been emerging as an important public health problem worldwide with the increase in host predisposition factors due to immunological dysregulations, immunosuppressive and/or anticancer therapy. Antifungal therapy for systemic mycosis is limited, most of times expensive and causes important toxic effects. Nanotechnology has become an interesting strategy to improve efficacy of traditional antifungal drugs, which allows lower toxicity, better biodistribution, and drug targeting, with promising results in vitro and in vivo. In this review, we provide a discussion about conventional antifungal and nanoantifungal therapies for systemic mycosis.

Clinical hepatotoxicity associated with antifungal agents

INTRODUCTION

Invasive fungal diseases (IFDs) are a leading cause of morbidity and mortality among immunocompromised patients with bone marrow failure syndromes, hematological malignancies, hematopoietic stem cell transplantation (HSCT), those admitted in intensive care units (ICUs) and those with prolonged febrile neutropenia. IFDs occur in a setting of multiple morbidities and are associated with case fatality rates between 30 and 70%. Along with the development of classes and compounds, the last two decades have seen substantial improvements in the prevention and management of these infections and an overall increased use of antifungal agents. Areas covered: All antifungal agents, including amphotericin B formulations, echinocandins and the triazoles, may cause hepatic toxicity that ranges from mild and asymptomatic abnormalities in liver function tests to substantial liver injury and fulminant hepatic failure. Expert opinion: The present article reviews incidence and severity of hepatotoxicity associated with different classes and agents to provide a better understanding of this specific end organ toxicity and safer use of antifungal agents A thorough understanding of the distribution, metabolism, elimination and drug-drug interactions of antifungal agents used for management of IFDs in combination with safety data from clinical trials, pharmacokinetic and pharmacodynamic studies may guide the use of antifungal treatment in patients at high risk for the development of hepatic dysfunction and in those with underlying liver damage due to cytotoxic therapy.

Safety and efficacy of treatment with liposomal amphotericin B in elderly patients at least 65 years old with hematological diseases

The safety and efficacy of treatment with liposomal amphotericin B (L-AMB) in elderly patients has not been clarified, especially in Japanese patients. Therefore, we retrospectively analyzed 33 elderly patients with hematological diseases of at least 65 years old who received L-AMB between 2009 and 2012. Their clinical outcomes were compared to those of 21 patients who were younger than 65 years. L-AMB was administered for empirical therapy (n = 2) or target therapy for possible (n = 14) or probable/proven (n = 17) invasive fungal infection. There was no discontinuation of L-AMB due to adverse events. More than 2-fold increases from the baseline Cre, AST, and ALT values were observed in 21.2%, 39.4%, and 45.5% of the older group and 38.1%, 61.9%, and 52.4% of the younger group, respectively. The concurrent use of nephrotoxic antibiotics was the only risk factor for the development of a 2-fold increase in the serum Cre level. The duration of L-AMB was significantly longer in patients who developed grade III-IV hypokalemia. A partial or complete response was observed in 54.8% and 62.5% of the elderly and younger groups, respectively. In conclusion, L-AMB therapy appeared to be acceptably safe as empirical therapy or treatment for invasive fungal infection.

Voriconazole-Induced Hepatitis via Simvastatin- and Lansoprazole-Mediated Drug Interactions: A Case Report and Review of the Literature

Therapeutic voriconazole concentrations have a narrow window of effectiveness before causing cholestatic hepatitis. After undergoing 1 year of voriconazole therapy for pulmonary aspergillosis, a 44-year-old man began treatment with 30 mg lansoprazole for gastroesophageal reflux symptoms. Within 5 days of starting treatment with lansoprazole, the patient presented with fatigue, jaundice, and cholestatic hepatitis. The hepatitis promptly resolved after stopping lansoprazole treatment. Sixteen months later, the patient was given simvastatin therapy, as recommended by the American Diabetes Association to prevent cardiovascular disease for patients with diabetes who are aged >40 years and have one additional risk factor. Within 2 weeks of taking simvastatin, a 3-hydroxy-3-methylglutaryl CoA reductase (statin) therapy, the patient redeveloped fatigue, jaundice, and cholestatic hepatitis. He described both episodes of fatigue and jaundice similarly in terms of onset and intensity. Voriconazole is metabolized by both CYP2C19 and CYP3A4 isoenzymes. Lansoprazole is an inhibitor of the CYP2C19 isoenzyme. Competition between voriconazole and lansoprazole likely led to increased voriconazole serum concentration and acute cholestatic hepatitis in this patient. Simvastatin inhibits the CYP3A4 isoenzyme. After the patient took 10 mg simvastatin daily for 2 weeks, cholestatic hepatitis occurred. The voriconazole concentration remained elevated (4.1 μg/ml) when measured 15 days after stopping simvastatin. The patient's Naranjo Adverse Drug Reaction Probability Scale score of 7 revealed that the cholestatic hepatitis was probably precipitated by lansoprazole. Likewise, the patient's Naranjo score of 9 also revealed that cholestatic hepatitis was attributable to a definite adverse drug reaction precipitated by the addition of simvastatin to the stable baseline regimen of voriconazole. In a single patient, two different inhibitors of the cytochrome P450 pathway stimulated voriconazole-induced cholestatic hepatitis. Although the major cytochrome P450 pathways for the metabolism and clearance of lansoprazole and simvastatin are different, they both likely contributed to the reduced hepatic clearance of voriconazole in this patient.

Application of Culture-Independent Rapid Diagnostic Tests in the Management of Invasive Candidiasis and Cryptococcosis

The diagnosis of invasive candidiasis (IC) and cryptococcosis is often complicated by slow and insensitive culture-based methods. Such delay results in poor outcomes due to the lack of timely therapeutic interventions. Advances in serological, biochemical, molecular and proteomic approaches have made a favorable impact on this process, improving the timeliness and accuracy of diagnosis with resultant improvements in outcome. This paper will serve as an overview of recent developments in the diagnostic approaches to infections due to these important yeast-fungi.

Isavuconazole, a broad-spectrum triazole for the treatment of systemic fungal diseases

The prodrug isavuconazonium sulfate (BAL8557) is an extended-spectrum water-soluble triazole, developed for the treatment of severe invasive and life-threatening fungal diseases. Its active moiety, BAL4815, is a potent inhibitor of ergosterol biosynthesis, resulting in the disruption of fungal membrane structure and function. The active compound shows broad-spectrum of activity and potency against all major opportunistic fungi, such as Aspergillus spp., Candida spp., Cryptococcus spp., Mucorales, Black yeasts and their filamentous relatives and the true pathogenic fungi, including Histoplasma capsulatum and Blastomyces dermatitidis. It is currently in Phase III clinical development for treatment of aspergillosis, candidiasis and mucormycosis, as well as other rare fungi infections. We reviewed the pharmacokinetic and pharmacodynamic characteristics of isavuconazole, and its microbiological and clinical investigation progress in advanced stages of development.

Antifungals in severe asthma

PURPOSE OF REVIEW

Despite guideline-based treatment, many patients with severe asthma continue to have uncontrolled disease. Fungal allergy is being increasingly recognized in the pathogenesis of severe asthma. Limited data exist on the approach to treatment of fungal asthma. This review summarizes existing evidence on the use of antifungal agents in allergic bronchopulmonary aspergillosis (ABPA) and severe asthma with fungal sensitization (SAFS), and highlights needed areas of future investigation.

RECENT FINDINGS

Recent studies evaluating oral triazole therapy in ABPA appear to support triazole use in a carefully considered clinical setting, whereas studies assessing triazole use in SAFS have yielded mixed results. Despite early encouraging findings that oral triazole use may improve asthma symptoms, stabilize lung function, decrease inhaled and systemic corticosteroid requirements, and alter serum biomarkers, overall data are limited. Appropriate patient selection, as well as choice of the optimal drug, dose, frequency, and duration of therapy, remains poorly defined.

SUMMARY

The role of antifungal therapy in severe asthma remains unclear. Early studies have suggested a possible benefit of some antifungal agents, such as oral triazoles in ABPA and SAFS; however, routine clinical use of these agents in severe asthma without ABPA is not currently recommended. Further research is needed to better delineate the potential utility of antifungal medications in severe asthma and identify the asthma populations who benefit from such treatment.

The role of azoles in the management of azole-resistant aspergillosis: from the bench to the bedside

Azole resistance is an emerging problem in Aspergillus fumigatus and is associated with a high probability of treatment failure. An azole resistance mechanism typically decreases the activity of multiple azole compounds, depending on the mutation. As alternative treatment options are limited and in some isolates the minimum inhibitory concentration (MIC) increases by only a few two-fold dilutions steps, we investigated if voriconazole and posaconazole have a role in treating azole-resistant Aspergillus disease. The relation between resistance genotype and phenotype, pharmacokinetic and pharmacodynamic properties, and (pre)clinical treatment efficacy were reviewed. The results were used to estimate the exposure needed to achieve the pharmacodynamic target for each MIC. For posaconazole adequate exposure can be achieved only for wild type isolates as dose escalation does not allow PD target attainment. However, the new intravenous formulation might result in sufficient exposure to treat isolates with a MIC of 0.5 mg/L. For voriconazole our analysis indicated that the exposure needed to treat infection due to isolates with a MIC of 2 mg/L is feasible and maybe isolates with a MIC of 4 mg/L. However, extreme caution and strict monitoring of drug levels would be required, as the probability of toxicity will also increase.

Occurrence of azole-resistant species of Aspergillus in the UK environment

The aim of this study was to survey environmental isolates of Aspergillus resistant to azoles in azole-treated and naïve areas to determine whether resistance could be related to azole treatment history. Aspergillus fumigatus was sampled from the centre of a large city and from fields with known azole history. Azole resistance was determined and sequencing was performed to identify strains and mutations in the cyp51A gene. Azole resistance was detected in azole-treated field isolates but not in urban isolates (P=0.038). In addition, an azole-resistant isolate of Neosartorya fischeri was isolated. These results support the hypothesis that agricultural azole use may lead to resistance in environmental fungi of clinical importance. We report the first environmental UK TR₃₄/L98H isolate of A. fumigatus.

Exploring azole antifungal drug resistance in Aspergillus fumigatus with special reference to resistance mechanisms

ABSTRACT: 

Aspergillus fumigatus, a ubiquitously distributed opportunistic pathogen, is the global leading cause of aspergillosis. Azole antifungals play an important role in the management of aspergillosis. However, over a decade, azole resistance in A. fumigatus isolates has been increasingly reported with variable prevalence worldwide and it is challenging the effective management of aspergillosis. The high mortality rates observed in patients with invasive aspergillosis caused by azole-resistant A. fumigatus (ARAF) isolates pose serious challenges to the clinical microbiologist for timely identification of resistance and appropriate therapeutic interventions. The majority of ARAF isolates contain alterations in the cyp51A gene; however, there have been increasing reports on non-cyp51A mutations contributing to azole resistant phenotypes. This review highlights the emergence and various mechanisms implicated in the development of azole resistance in A. fumigatus. We further present recent developments related to the environmental route in the emergence of ARAF isolates and discuss the therapeutic options available.

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.

Flucytosine and cryptococcosis: time to urgently address the worldwide accessibility of a 50-year-old antifungal

Current, widely accepted guidelines for the management of HIV-associated cryptococcal meningoencephalitis (CM) recommend amphotericin B combined with flucytosine (5-FC) for ≥2 weeks as the initial induction treatment of choice. However, access to flucytosine in Africa and Asia, where disease burden is greatest, is inadequate at present. While research into identifying effective and well-tolerated antifungal combinations that do not contain flucytosine continues, an ever-increasing body of evidence from in vitro, in vivo and clinical studies points to the benefits of flucytosine in the treatment of CM in both intravenous combinations with amphotericin B and oral combinations with high-dose fluconazole. This article provides an up-to-date review of this evidence, and the current issues and challenges regarding increasing access to this key component of combination antifungal therapy for cryptococcosis.

A review of clinical experience with newer antifungals in children

Fungal infections are a significant cause of morbidity and mortality in immunocompromised children. Since the beginning of the 21st century, many new antifungals including the echinocandins (i.e., caspofungin, micafungin, anidulafungin) and the newer generation triazoles (i.e., voriconazole and posaconazole) have received Food and Drug Administration approval. Unfortunately, despite making great strides in the adult arena, these agents are not currently approved in the pediatric population. However, pharmacokinetic data and clinical experiences with these agents in infants, children, and adolescents are mounting. As such, this review will discuss key concepts in pediatric pharmacology and clinical use of these newer antifungal agents.

Antifungal agents for the treatment of systemic fungal infections in children

Traditionally, the mainstay of systemic antifungal therapy has been amphotericin B deoxycholate (conventional amphotericin B). Newer agents have been developed to fulfill special niches and to compete with conventional amphotericin B by virtue of having more favourable toxicity profiles. Some agents have displaced conventional amphotericin B for the treatment of specific fungal diseases. For example, voriconazole has emerged as the preferred treatment for invasive pulmonary aspergillosis. This notwithstanding, conventional amphotericin B remains a useful agent for the treatment of paediatric fungal infections. Knowledge of the characteristics of the newer agents is important, given the increasing numbers of patients who are being treated with these drugs. Efforts need to be directed at research aimed at generating paediatric data where these are lacking. The antifungal agents herein described are most often used as monotherapy regimens because there is no uniform consensus on the value of combination therapy, except for specific scenarios.

Importance of pharmacokinetic considerations for selecting therapy in the treatment of invasive fungal infections

Invasive fungal infections continue to be a significant cause of morbidity and mortality among at-risk patients. Over the last decade, the epidemiology of invasive mycoses has been defined by increasing rates of infection caused by azole-resistant yeast (Candida glabrata, Candida krusei), Aspergillus, and in some centers, non-Aspergillus moulds, such as Fusarium species, Scedosporium species, and Mucorales. Early and appropriate antifungal therapy is crucial for a favorable clinical outcome. When selecting antifungal therapy--especially during the initial acute phases of treatment--spectrum of activity and pharmacokinetic characteristics are key treatment considerations. Important pharmacokinetic considerations for selecting antifungal therapy in the treatment of invasive fungal infections include drug-drug interactions and variability in adsorption that may limit efficacy during the early phase of treatment, poor oral availability, and variable tissue distribution. A patient's underlying condition and pharmacogenetics also may affect the pharmacokinetics of antifungal drugs, resulting in interpatient pharmacokinetic differences.

Invasive mycoses: strategies for effective management

Effective management of invasive fungal infections (IFIs) depends on early individualized therapy that optimizes efficacy and safety. Considering the negative consequences of IFI, for some high-risk patients the potential benefits of prophylactic therapy may outweigh the risks. When using a prophylactic, empiric, or preemptive therapeutic approach, clinicians must take into account the local epidemiology, spectrum of activity, pharmacokinetic and pharmacodynamic parameters, and safety profile of different antifungal agents, together with unique host-related factors that may affect antifungal efficacy or safety. Therapeutic drug monitoring is increasingly recognized as important or necessary when employing lipophilic triazoles (itraconazole, voriconazole, posaconazole) or flucytosine. Because early diagnostics remain limited for uncommon, yet emerging opportunistic molds (e.g., Mucorales), and treatment delay is associated with increased mortality, early effective management often depends on a high index of suspicion, taking into account predisposing factors, host cues favoring mucormycosis, and local epidemiology. Antifungal options for mucormycosis are limited, and optimal management depends on a multimodal approach that includes early diagnosis/clinical suspicion, correction of underlying predisposing factors, radical debridement of affected tissues, and extended antifungal therapy. This article discusses strategies for the effective management of invasive mycoses, with a particular focus on antifungal hepatotoxicity.

Nasal polyposis: current trends

Nasal polyps (NP) are one of the most common inflammatory mass lesions of the nose, affecting up to 4% of the population. They present with nasal obstruction, anosmia, rhinorrhoea, post nasal drip, and less commonly facial pain. Their etiology remains unclear, but they are known to have associations with allergy, asthma, infection, fungus, cystic fibrosis, and aspirin sensitivity. However, the underlying mechanisms interlinking these pathologic conditions to NP formation remain unclear. Also strong genetic factors are implicated in the pathogenesis of NP, but genetic and molecular alterations required for its development and progression are still unclear. Management of NP involves a combination of medical therapy and surgery. There is good evidence for the use of corticosteroids (systemic and topical) both as primary treatment and as postoperative prophylaxis against recurrence, but the prolonged course of the disease and adverse effects of systemic steroids limits their use. Hence several new drugs are under trial. Surgical treatment has been refined significantly over the past 20 years with the advent of endoscopic sinus surgery and, in general, is reserved for cases refractory to medical treatment. Recurrence of the polyposis is common with severe disease recurring in up to 10% of patients. Over the last two decades, increasing insights in the pathophysiology of nasal polyposis opens perspective for new pharmacological treatment options, with eosinophilic inflammation, IgE, fungi and Staphylococcus aureus as potential targets. A better understanding of the pathophysiology underlying the persistent inflammatory state in NP is necessary to ultimately develop novel pharmacotherapeutic approaches. In this paper we present the newer treatment options available for better control and possibly cure of the disease.

Diagnosis and therapy of Candida infections: joint recommendations of the German Speaking Mycological Society and the Paul-Ehrlich-Society for Chemotherapy

Invasive Candida infections are important causes of morbidity and mortality in immunocompromised and hospitalised patients. This article provides the joint recommendations of the German-speaking Mycological Society (Deutschsprachige Mykologische Gesellschaft, DMyKG) and the Paul-Ehrlich-Society for Chemotherapy (PEG) for diagnosis and treatment of invasive and superficial Candida infections. The recommendations are based on published results of clinical trials, case-series and expert opinion using the evidence criteria set forth by the Infectious Diseases Society of America (IDSA). Key recommendations are summarised here: The cornerstone of diagnosis remains the detection of the organism by culture with identification of the isolate at the species level; in vitro susceptibility testing is mandatory for invasive isolates. Options for initial therapy of candidaemia and other invasive Candida infections in non-granulocytopenic patients include fluconazole or one of the three approved echinocandin compounds; liposomal amphotericin B and voriconazole are secondary alternatives because of their less favourable pharmacological properties. In granulocytopenic patients, an echinocandin or liposomal amphotericin B is recommended as initial therapy based on the fungicidal mode of action. Indwelling central venous catheters serve as a main source of infection independent of the pathogenesis of candidaemia in the individual patients and should be removed whenever feasible. Pre-existing immunosuppressive treatment, particularly by glucocorticosteroids, ought to be discontinued, if feasible, or reduced. The duration of treatment for uncomplicated candidaemia is 14 days following the first negative blood culture and resolution of all associated symptoms and findings. Ophthalmoscopy is recommended prior to the discontinuation of antifungal chemotherapy to rule out endophthalmitis or chorioretinitis. Beyond these key recommendations, this article provides detailed recommendations for specific disease entities, for antifungal treatment in paediatric patients as well as a comprehensive discussion of epidemiology, clinical presentation and emerging diagnostic options of invasive and superficial Candida infections.

Diagnosis and treatment of chronic rhinosinusitis: focus on intranasal Amphotericin B

Chronic rhinosinusitis (CRS) is a chronic disease that affects 14.2% of the US adult population. Despite being widespread, little is known about the etiology of CRS. Treatment has been symptomatic and focused on relieving symptoms. Recent investigations into causes of CRS have revealed that most CRS patients have an eosinophilic infiltration of their nasal tissue (mucosa), regardless of atopy and elevated immunoglobulin E levels. Although fungi are ubiquitous and in the nasal mucus of both healthy people and patients, it is only in the patients that the eosinophils (part of the inflammatory response) are found. Fungi in the nasal mucus are harmless, yet in CRS patients these same fungi stimulate an inflammatory response, inducing the eosinophils to leave the blood vessels and enter the nasal and sinus tissue and ultimately enter the nasal airway mucus. In the nasal mucus these eosinophils attack the fungi and destroy the fungi by the release of a toxic substance called major basic protein (MBP) from the granules in the eosinophils. This degranulation and release of the toxic MBP not only destroys fungi, but also produces collateral damage injuring the nasal and sinus mucosal lining tissue. The injury to the mucosal lining makes the nasal and sinus mucosa susceptible to penetration and potential infection by bacteria. When this tissue inflammation and damage is persistent and prolonged we call it CRS. The diagnosis of CRS is based largely on symptomatic criteria, with anterior rhinoscopy or endoscopy, and, if there is any doubt about the diagnosis, computed tomography imaging is employed to confirm the presence of diseased sinus mucosa. Treatment of CRS, whether medical (intranasal corticosteroids, saline irrigations) or surgical, is aimed at decreasing inflammation and obstruction in the sinonasal passages. Antibiotics, although commonly used in CRS, should not be administered unless there is suspicion of an acute bacterial infection. The theory behind the fungal and eosinophilic etiology of CRS has led to use of an antifungal compound, intranasal Amphotericin B. In clinical studies, topical irrigation with Amphotericin B has been shown to be both a safe and effective treatment for CRS.

Azole resistance in Aspergillus fumigatus: a new challenge in the management of invasive aspergillosis?

Azole resistance is emerging in Aspergillus fumigatus isolates. The exact mechanism of evolution of azole resistance has not been fully elucidated yet but increasing evidence indicates a role for azole fungicide used in agriculture. Patients confronted with an invasive fungal infection from an azole-resistant A. fumigatus isolate will fail azole treatment. Azole resistance in A. fumigatus isolates impacts the management of invasive aspergillosis (IA) since the azoles are the primary agents used for prophylaxis and treatment. Because A. fumigatus will always be present in our environment and also in the close vicinity of patients at risk for IA, there is an urgent need to understand the evolution of the increasing azole resistance in A. fumigatus. Thereby, induction of azole resistance or its spread can possibly be prevented to allow future treatment of A. fumigatus IA.

Update on the optimal use of voriconazole for invasive fungal infections

Voriconazole is an extended-spectrum triazole with excellent bioavailability that has now become the treatment of choice for aspergillosis. It has a unique side effect profile compared with other azoles, as well as a number of clinically important drug-drug interactions. These factors, along with a correlation between increased serum levels and improved outcomes, have prompted an interest in therapeutic drug monitoring of this agent. The pharmacology and clinical outcomes data of voriconazole are presented in this review.

Posaconazole for paediatric patients: status of development and future perspectives

Posaconazole is a novel oral antifungal triazole with potent and broad-spectrum antifungal activity, favourable pharmacokinetic properties and a limited spectrum of adverse events. The compound has documented clinical efficacy in the settings of oropharyngeal candidiasis, refractory aspergillosis, fusariosis, zygomycosis, and as antifungal prophylaxis in high-risk patients with acute myeloblastic leukaemia or graft-vs.-host disease. Whereas, posaconazole is approved for use in adults, however, the appropriate dosage and the safety of the compound have not been systematically investigated in paediatric age groups. This paper reviews the relevant pharmacological characteristics of posaconazole, the published data on its use in paediatric patients without therapeutic alternative and perspectives for the clinical development in paediatric patients at risk for invasive fungal infections.

Recent advances in antifungal prevention and treatment

Invasive fungal infections are important causes of morbidity and mortality in patients with bone marrow failure syndromes and hematological malignancies, or who are undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Current epidemiological trends indicate a shift toward infections by Aspergillus spp., non-albicans Candida spp., and previously uncommon fungal pathogens that have decreased susceptibility to the available antifungal agents. The last two decades have seen substantial improvements in the clinical, laboratory, and radiological diagnosis of these infections and the development of new antifungal compounds. Progress has been made in establishing disease definitions and paradigms for antifungal intervention and in the design and conduct of interventional clinical trials. Collectively, these advances have led to major but ongoing changes in the management of patients at risk of or being affected by invasive fungal infections. This article reviews current approaches to prevention and treatment of opportunistic fungal infections in immunocompromised patients with hematological disorders and discusses novel approaches to antifungal chemotherapy and adjunctive treatments.

Safety, tolerance and outcome of treatment with liposomal amphotericin B in paediatric patients with cancer or undergoing haematopoietic stem cell transplantation

OBJECTIVES

To assess safety, tolerance and efficacy of liposomal amphotericin B (LAMB) in a large unselected series of paediatric cancer/haematopoietic stem cell transplantation (HSCT) patients requiring LAMB therapy.

PATIENTS AND METHODS

The study included 84 children and adolescents (median age: 11 years) who received 141 consecutive courses of LAMB for prophylaxis (32), empirical therapy (83), possible (19) or probable/proven (7) invasive infections. LAMB was administered until intolerance or maximum efficacy at dosages individually determined by the responsible physician.

RESULTS

Fifty-nine courses were post-HSCT (42%, 49 allogeneic), and 92 courses were started during granulocytopenia (65%). The median duration of LAMB therapy was 13 days (range 1-79), and the median maximum dosage was 2.8 mg/kg (range 0.93-5.10). Mild-to-moderate adverse events were noted during 109 courses (77%; hepatic, 58.8%; electrolyte wasting, 52.5%; renal, 31.9%; infusion-related reactions, 8.5%); adverse events necessitating discontinuation of LAMB occurred in 6 courses (4.3%; renal, 3; anaphylaxis, 2; hepatic, 1). While median hepatic transaminase, alkaline phosphatase and blood urea nitrogen values were slightly (P < 0.01) higher at end of treatment (EOT), bilirubin and creatinine values were not different from baseline. Complete or partial responses were observed in 16/19 and 2/7 courses for possible and probable/proven invasive infections. Thirty-two of 33 courses of prophylaxis and 74 of 83 courses of empirical therapy were completed with success. Overall survival was 90.8% at 3 months post-EOT.

CONCLUSIONS

LAMB had acceptable safety and tolerance and was useful in prevention and treatment in unselected, mostly granulocytopenic paediatric patients undergoing treatment for cancer or HSCT.

Fungal brain infections

PURPOSE OF REVIEW

Fungal infections of the central nervous system, once a relatively rare occurrence, are increasingly common due to the expansion of immunocompromised populations at risk, and therefore are important to recognize early and manage appropriately.

RECENT FINDINGS

The specific infectious risk posed by novel immune-modifying therapies can, in most cases, be predicted on the basis of the immune target and medication timing. In addition, major advances in noninvasive diagnostic tests (e.g. serum beta glucan and galactomannan assays), and the recent introduction of more effective antifungal therapies, have led to a dramatic improvement in clinical outcomes.

SUMMARY

The current review provides approaches to patients with suspected central nervous system fungal infections based on host-risk factors, clinical syndromes and specific pathogens.