Antifungal treatment strategies in high risk patients

Clinical safety and efficacy of novel antifungal, fosmanogepix, for the treatment of candidaemia: results from a Phase 2 trial

BACKGROUND

Fosmanogepix is a first-in-class antifungal targeting the fungal enzyme Gwt1, with broad-spectrum activity against yeasts and moulds, including multidrug-resistant fungi, formulated for intravenous (IV) and oral administration.

METHODS

This global, multicenter, non-comparative study evaluated the safety and efficacy of fosmanogepix for first-line treatment of candidaemia in non-neutropenic adults. Participants with candidaemia, defined as a positive blood culture for Candida spp. within 96 h prior to study entry, with ≤2 days of prior systemic antifungals, were eligible. Participants received fosmanogepix for 14 days: 1000 mg IV twice daily on Day 1, followed by maintenance 600 mg IV once daily, and optional switch to 700 mg orally once daily from Day 4. Eligible participants who received at least one dose of fosmanogepix and had confirmed diagnosis of candidaemia (<96 h of treatment start) composed the modified intent-to-treat (mITT) population. Primary efficacy endpoint was treatment success at the end of study treatment (EOST) as determined by the Data Review Committee. Success was defined as clearance of Candida from blood cultures with no additional antifungal treatment and survival at the EOST.

RESULTS

Treatment success was 80% (16/20, mITT; EOST) and Day 30 survival was 85% (17/20; 3 deaths unrelated to fosmanogepix). Ten of 21 (48%) were switched to oral fosmanogepix. Fosmanogepix was well tolerated with no treatment-related serious adverse events/discontinuations. Fosmanogepix had potent in vitro activity against baseline isolates of Candida spp. (MICrange: CLSI, 0.002-0.03 mg/L).

CONCLUSIONS

Results from this single-arm Phase 2 trial suggest that fosmanogepix may be a safe, well-tolerated, and efficacious treatment for non-neutropenic patients with candidaemia, including those with renal impairment.

Invasive fungal infections in hemato-oncology

BACKGROUND

Patients with hematologic malignancies (HM) carries a significant risk of developing invasive fungal infection (IFI) and are associated with a high risk of attributable morbidity and mortality.

OBJECTIVES

This review has highlighted the importance of diagnosis and management of invasive fungal infections in highly immunocompromised Hemato-Oncology patients.

CONTENT

IFI continues to be a therapeutic issue in immunocompromised HM patients despite of many advancements in the field of fungal diagnosis and therapies. Non-specific and often overlapping signs and symptoms render fungal infections clinically undifferentiated from bacterial infections. Definite diagnosis requires microbiological diagnostic procedures in addition to imaging techniques. Many international committees have formulated definitions to aid in the diagnosis of IFI in immunocompromised patients and assigned 3 levels of probability to the diagnosis "proven," "probable," and "possible" IFI. Early specific risk-based antifungal strategies such as prophylaxis, pre-emptive and empirical therapies, are common practices in HM patients. For low-risk patients, fluconazole is recommended as primary prophylaxis, while, posaconazole and voriconazole are recommended for high-risk patients. Emerging antifungal-resistant IFIs and breakthrough fungal infections are the new threat to these heavily immunosuppressed patients. Antifungal agents such as azoles have variable pharmacokinetics leading to uncertainty in the drug dose-exposure relationship, especially in the initiation phase. TDM (therapeutic drug monitoring) of voriconazole is strongly recommended.

Aspergillus fumigatus Can Display Persistence to the Fungicidal Drug Voriconazole

Aspergillus fumigatus is a filamentous fungus that can infect the lungs of patients with immunosuppression and/or underlying lung diseases. The mortality associated with chronic and invasive aspergillosis infections remain very high, despite availability of antifungal treatments. In the last decade, there has been a worrisome emergence and spread of resistance to the first-line antifungals, the azoles. The mortality caused by resistant isolates is even higher, and patient management is complicated as the therapeutic options are reduced. Nevertheless, treatment failure is also common in patients infected with azole-susceptible isolates, which can be due to several non-mutually exclusive reasons, such as poor drug absorption. In addition, the phenomena of tolerance or persistence, where susceptible pathogens can survive the action of an antimicrobial for extended periods, have been associated with treatment failure in bacterial infections, and their occurrence in fungal infections already proposed. Here, we demonstrate that some isolates of A. fumigatus display persistence to voriconazole. A subpopulation of the persister isolates can survive for extended periods and even grow at low rates in the presence of supra-MIC of voriconazole and seemingly other azoles. Persistence cannot be eradicated with adjuvant drugs or antifungal combinations and seemed to reduce the efficacy of treatment for certain individuals in a Galleria mellonella model of infection. Furthermore, persistence implies a distinct transcriptional profile, demonstrating that it is an active response. We propose that azole persistence might be a relevant and underestimated factor that could influence the outcome of infection in human aspergillosis. IMPORTANCE The phenomena of antibacterial tolerance and persistence, where pathogenic microbes can survive for extended periods in the presence of cidal drug concentrations, have received significant attention in the last decade. Several mechanisms of action have been elucidated, and their relevance for treatment failure in bacterial infections demonstrated. In contrast, our knowledge of antifungal tolerance and, in particular, persistence is still very limited. In this study, we have characterized the response of the prominent fungal pathogen Aspergillus fumigatus to the first-line therapy antifungal voriconazole. We comprehensively show that some isolates display persistence to this fungicidal antifungal and propose various potential mechanisms of action. In addition, using an alternative model of infection, we provide initial evidence to suggest that persistence may cause treatment failure in some individuals. Therefore, we propose that azole persistence is an important factor to consider and further investigate in A. fumigatus.

Molecular identification of Aspergillus fumigatus complex from lung transplant recipients using multilocus sequencing analysis (MLSA)

BACKGROUND

Aspergillus infection causes significant morbidity and mortality among lung transplant recipients (LTRs). It is primarily caused by Aspergillus fumigatus. Other closely related species belonging to the section Fumigati have also been found. These cryptic species are often misidentified as A. fumigatus. Thus, we used multilocus sequencing analysis (MLSA) of the calmodulin, β-tubulin, and hydrophobin gene sequences to identify these species and to determine the frequency with which they occur among LTRs.

METHODS

A total of 81 A. fumigatus isolates were initially isolated from bronchoalveolar lavage fluid or sputum specimens collected from lung transplant patients. These isolates were then sub-cultured and genotyped using MLSA. Of these isolates, 53, 17, and 11 were isolated from double LTRs, single LTRs, and pre-LTRs, respectively.

RESULTS

All isolates (100%) carried DNA sequences identical to those of A. fumigatus reference strains and thus clustered in the same clade with A. fumigatus. Analysis of the MLSA data revealed that A. fumigatus species were the only species recovered in this population of LTRs. The MLSA results were consistent with those routinely obtained by conventional mycological procedures in the microbiology laboratory.

CONCLUSIONS

A. fumigatus appears to be the primary causative agent of colonization or invasive aspergillosis among LTRs. No cryptic species were identified.

Effect of CYP2C19 polymorphism on the plasma voriconazole concentration and voriconazole-to-voriconazole-N-oxide concentration ratio in elderly patients

BACKGROUND

Effects of CYP2C19 polymorphism on voriconazole concentration (C0 ), dose-adjusted trough concentrations (C0 /dose) and voriconazole-to-voriconazole-N-oxide concentration ratio (C0 /CN ) have not been fully investigated.

OBJECTIVES

To investigate correlations of CYP2C19 polymorphisms with plasma concentrations of voriconazole and the major metabolite voriconazole-N-oxide in elderly patients.

METHODS

A prospective, multi-centre, non-intervention, open clinical study was conducted within Southwestern Chinese patients clinically diagnosed with invasive fungal infections, to investigate the associations of CYP2C19∗2 (681G > A), CYP2C19∗3 (636G > A) and CYP2C19∗17 (-806C > T) genetic polymorphisms with voriconazole C0 , C0 /dose and C0 /CN .

RESULTS

The study included 131 adult patients, of which 72 were elderly (≥60 years) and 59 were adults (<60 years). The allele frequencies of CYP2C19∗2, ∗3 and ∗17 in the elderly cohort were 61.1%, 29.9% and 7.6%, respectively, which were similar to those in the adult cohort (66.9%, 29.7% and 2.5%, respectively; P > .05). The median voriconazole C0 (C0 ), C0 /dose and C0 /CN ratio in patients with the CYP2C19∗1/∗2 and CYP2C19∗2/∗2 genotypes were significantly higher than those in patients with the CYP2C19∗1/∗1 genotype in the adult cohort (P < .05). The C0 and C0 /dose in patients with the CYP2C19∗1/∗3 and CYP2C19∗2/∗2 genotypes, and the C0 /CN ratio for patients with the CYP2C19∗1/∗2 genotype were numerically higher than those in patients with the CYP2C19∗1/∗1 genotype in the elderly cohort, but this difference was not statistically significant (P > 0.05). The C0 , C0 /dose and C0 /CN in patients with poor metaboliser phenotypes were higher than in those with normal metaboliser phenotypes and C0 in patients with intermediate metaboliser phenotypes were significantly higher than in those with normal metaboliser phenotypes in the adult cohort (P < .05). However, there were no significant differences in the C0 , C0 /dose and C0 /CN among different CYP2C19-predicted metabolic phenotypes in the elderly cohort.

CONCLUSIONS

Voriconazole C0 , C0 /dose and C0 /CN ratio are not significantly affected by the CYP2C19∗2/∗3 polymorphisms in the elderly patients.

Emerging Candida species isolated from renal transplant recipients: Species distribution and susceptibility profiles

Candidiasis is a major challenge among renal transplant recipients (RTRs) worldwide and is associated with high morbidity and mortality rates. Fluconazole is the most commonly used agent for Candida infections. However, frequent relapse and treatment failure are still reported among patients affected with this infection. In the present study, Candida species obtained from RTRs were characterized based on conventional and molecular assays. Furthermore, the antifungal susceptibility profiles of these species were determined. This study was conducted on a total of 126 RTRs within 2012-2016. The patients were categorized according to the referenced diagnostic criteria. The identification of Candida species was accomplished based on conventional examination, assimilation profile test, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The minimum inhibitory concentrations (MICs) of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin were determined based on the guidelines of Clinical and Laboratory Standards Institute. The patients with Candida infection were diagnosed with urinary tract candidiasis (n = 17), peritonitis (n = 8), intra-abdominal candidiasis (n = 6), candidemia (n = 4), hepatosplenic candidiasis (n = 3), and Candida pneumonia (n = 3). A total of 41 Candida isolates, including C. albicans (n = 18), C. famata (n = 8), C. kefyr (n = 4), C. tropicalis (n = 4), C. parapsilosis (n = 3), C. glabrata (n = 2), and C. lusitaniae (n = 2), were isolated from 32.5% (41/126) renal transplant recipients. Fluconazole-resistance was observed in seven isolates, entailing C. albicans (n = 6) and C. tropicalis (n = 1). Fluconazole MIC for C. lusitaniae isolates was above the epidemiologic cut-off value (4-16 μg/ml). Furthermore, MIC range values of fluconazole against C. famata and C. kefyr were obtained as 4-32 μg/ml and 4-8 μg/ml, respectively. Posaconazole exhibited potent activity against Candida isolates, followed by caspofungin. The identification of Candida species, together with susceptibility testing, provides important data about the geographic trends of the fluconazole-resistance profiles of Candida species. It is necessary to maintain a consistent method for the implementation of early diagnosis and adoption of treatment regimen.

Pharmacodynamic studies of voriconazole: informing the clinical management of invasive fungal infections

INTRODUCTION

Voriconazole is a broad-spectrum antifungal agent commonly used to treat invasive fungal infections (IFI), including aspergillosis, candidiasis, Scedosporium infection, and Fusarium infection. IFI often occur in immunocompromised patients, leading to increased morbidity and mortality.

AREAS COVERED

The objective of this review is to summarize the pharmacodynamic properties of voriconazole and to provide considerations for potential optimal dosing strategies. Studies have demonstrated superior clinical response when an AUC/MIC >25 or Cmin/MIC >1 is attained in adult patients, correlating to a trough concentration range as narrow as 2-4.5 mg/L; however, these targets are poorly established in the pediatric population. Topics in this discussion include voriconazole use in multiple age groups, predisposing patient factors for IFI, and considerations for clinicians managing IFI. Expert commentary: The relationship between voriconazole dosing and exposure is not well defined due to the large inter- and intra-subject variability. Development of comprehensive decision support tools for individualizing dosing, particularly in children who require higher dosing, will help to increase the probability of achieving therapeutic efficacy and decrease sub-therapeutic dosing and adverse events.

Formulation and candidacidal activity of magnetic nanoparticles coated with cathelicidin LL-37 and ceragenin CSA-13

Fungal infections caused by Candida spp. represent an emerging problem during treatment of immunocompromised patients and those hospitalized with serious principal diseases. The ever-growing number of fungal strains exhibiting drug resistance necessitates the development of novel antimicrobial therapies including those based on membrane-permeabilizing agents and nanomaterials as drug carriers. In this study, the fungicidal activities of LL-37 peptide, ceragenin CSA-13 and its magnetic derivatives (MNP@LL-37, MNP@CSA-13) against laboratory and clinical strains of C. albicans, C. glabrata and C. tropicalis were evaluated. These experiments confirm the high anti-fungal activity of these well-characterized agents mediated by their interaction with the fungal membrane and demonstrate elevated activity following immobilization of LL-37 and CSA-13 on the surface of magnetic nanoparticles (MNPs). Furthermore, MNP-based nanosystems are resistant to inhibitory factors present in body fluids and effectively inhibit formation of fungal biofilm. Simultaneously, synthesized nanostructures maintain immunomodulatory properties, described previously for free LL-37 peptide and CSA-13 substrate and they do not interfere with the proliferation and viability of osteoblasts, confirming their high biocompatibility.

Critical review of current clinical practice guidelines for antifungal therapy in paediatric haematology and oncology

PURPOSE

The incidence of invasive fungal disease (IFD) is rising, but its treatment in paediatric haematology and oncology patients is not yet standardised. This review aimed to critically appraise and analyse the clinical practice guidelines (CPGs) that are available for paediatric IFD.

METHODS

Electronic searches of MEDLINE, MEDLINE in-Process & Other non-Indexed Citations, the Guidelines International Network (GIN), guideline.gov and Google were performed and combined fungal disease (Fung* OR antifung*OR Candida* OR Aspergill*) with prophylaxis or treatment (prophyl* OR therap* OR treatment). All guidelines were assessed using the AGREE II tool and recommendations relating to prophylaxis, empirical treatment and specific therapy were extracted.

RESULTS

Nineteen guidelines met the inclusion criteria. The AGREE II scores for the rigour of development domain ranged from 11 to 92 % with a median of 53 % (interquartile range 32-69 %). Fluconazole was recommended as antifungal prophylaxis in all nine of the included guidelines which recommended a specific drug. Liposomal amphotericin B was recommended in all five guidelines giving empirical therapy recommendations. Specific therapy recommendations were given for oral or genital candidiasis, invasive candida infection, invasive aspergillosis and other mould infections.

CONCLUSIONS

In many areas, recommendations were clear about appropriate practice but further clarity was required, particularly relating to the decision to discontinue empirical antifungal treatment, the relative benefits of empiric and pre-emptive strategies and risk stratification. Future CPGs could consider working to published guideline production methodologies and sharing summaries of evidence appraisal to reduce duplication of effort, improving the quality and efficiency of CPGs in this area.

Magnetic nanoparticles as a drug delivery system that enhance fungicidal activity of polyene antibiotics

This study was designed to assess the antifungal/anti-biofilm and hemolytic properties of two polyene antibiotics, amphotericin B (AMF) and nystatin (NYS), attached to the surface of magnetic nanoparticles (MNP) against clinical isolates of Candida species and human red blood cells, respectively. The developed nanosystems, MNP@AMF and MNP@NYS, displayed stronger fungicidal activity than unbound AMF or NYS. Synergistic activity was observed with a combination of polyenes and MNPs against all tested Candida strains. Nanosystems were more potent than unbound agents when tested against Candida strains in the presence of pus, and as agents able to prevent Candida biofilm formation. The observed inactivation of catalase Cat1 in Candida cells upon treatment with the nanosystems suggests that disruption of the oxidation-reduction balance is a mechanism leading to inhibition of Candida growth. The significant decrease of polyenes lytic activity against host cells after their attachment to MNPs surface indicates improvement in their biocompatibility.

Growth arrest and rapid capture of select pathogens following magnetic nanoparticle treatment

Thorough understanding of magnetic nanoparticle (MNP) properties is essential for developing new theranostics. In this study, we provide evidence that non-modified magnetic iron oxide nanoparticles and their functionalized derivatives may be used to restrict growth and capture different pathogens. Coprecipitation of Fe(2+) and Fe(3+) ions in an alkaline solution was used to synthesize MNPs that subsequently were functionalized by gold and aminosilane coating. Transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to assess their physicochemical properties. A significant decrease of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans outgrown from medium after addition of MNPs or their derivatives was observed during 24h culture. Measurement of optical density revealed that using MNPs, these pathogens can be quickly captured and removed (with efficiency reaching almost 100%) from purposely infected saline buffer and body fluids such as human blood plasma, serum, abdominal fluids and cerebrospinal fluids. These effects depend on nanoparticle concentration, surface chemistry, the type of pathogen, as well as the surrounding environment.

Empirical caspofungin therapy in clinical practice for suspected invasive fungal disease in adults with acute lymphoblastic leukaemia

Patients with acute lymphoblastic leukaemia (ALL) after cytotoxic chemotherapy or haematopoietic stem cell transplantation (HSCT) are at risk for life-threatening invasive fungal disease (IFD). The aim was to evaluate the characteristics, antifungal therapy and outcome of adult patients with ALL after chemotherapy or HSCT receiving caspofungin empirically in a clinical setting. Retrospective chart reviews were conducted at nine large tertiary care centres in Germany. Adult patients with ALL treated empirically with caspofungin according to the product label between 2006 and 2012 were eligible. Data were extracted as case reports. In total, 25 patients (12 males, 13 females; median age 37 years; 19 with B-ALL, 6 with T-ALL) with 28 treatment episodes because of suspected IFD (18 episodes after chemotherapy, 10 episodes after allogeneic HSCT) were included in the analysis. Empirical caspofungin therapy (median duration: 19 days, range 1-105 days) was given as first-line monotherapy in 20 (71.4%), second-line monotherapy in five (17.9%) and combination therapy in three (10.7%) episodes respectively. Therapy rated successful according to the physician's overall assessment (inflammatory parameters, clinical symptoms): 20 (95%) of 21 evaluable episodes with therapy duration of at least 8 days. Empirical caspofungin appears to be an effective therapeutic option in critically ill adult ALL patients with suspected IFD in clinical practice.

Application of caspofungin in China compared with amphotericin B and fluconazole

Fungal infection has increased in the past 2 decades in China. There are three classes of antifungal drugs, polyenes, azoles, and echinocandins, that are applied frequently in China. Caspofungin, which disrupts the fungal cell wall glucan formation through inhibiting the enzyme 1,3-β-glucan synthase, is one of the echinocandins. According to the results of clinical practices applied in China, caspofungin has shown to be superior to the other two classes of antifungal drugs, due to its efficacy in treating fungal infection (15% superior to fluconazole); fewer adverse events such as infusion-related reaction, hepatic dysfunction, and vomiting (25%-50% lower incidence rate); rapid resolution of symptoms (about 3 days quicker than amphotericin B); and absence of antagonism in combination with other antifungal drugs. However, caspofungin will remain as a second-line antifungal drug in the near future because of its high price and the policy of health insurance reimbursement in China.

Disseminated Fusarium infection in a patient with acute lymphoblastic leukemia: A case report and review of the literature

Fusarium is a common soil mold. In severely immunocompromised patients, this fungus may cause disseminated disease and is often confused with Aspergillus, as the two pathogens have similar histopathological appearances. Disseminated Fusarium infection may cause significant morbidity and mortality in immunocompromised patients. The current case report presents a 20-year-old male with acute lymphoblastic leukemia who developed disseminated Fusarium infection during induction chemotherapy. Early diagnosis and treatment is extremely important since the mortality rate is extremely high in such patients. The clinician must consider that the clinical presentation of Fusarium infection resembles that of Aspergillus. There is no optimal treatment for patients with Fusarium infection; however, combination antifungal therapy may have benefit without significant toxicity.

Voriconazole and its clinical potential in the prophylaxis of systemic fungal infection in patients with hematologic malignancies: a perspective review

Invasive fungal infections (IFIs) have become high prevalence in patients with hematologic malignancies. Drug-based strategies for IFIs include various approaches such as prophylactic, empiric, preemptive, and directed treatment. Prophylaxis is an attractive strategy in high-risk patients, given the lack of reliable diagnostics and the high mortality rate associated with IFIs. Prophylaxis includes the use of antifungal drugs in all patients at risk. An ideal antifungal compound for prophylaxis should have a potent and broad activity, be available both orally and intravenously, and have a low toxicity profile. Voriconazole fulfills all these criteria. The clinical efficacy of voriconazole against the majority of fungal pathogens makes it potentially very useful for the prevention of IFIs in patients with hematologic malignancies. Voriconazole appears to be very effective for the primary and secondary prevention of IFIs in these patients and recipients of allogeneic hematopoietic stem-cell transplantation. Randomized controlled trials evaluating voriconazole as primary antifungal prophylaxis in patients with neutropenia treated for a variety of hematologic malignancies have been performed, confirming its value as a prophylactic agent. Voriconazole is generally safe and well tolerated; however, its use is also associated with a number of concerns. In most patients with hematologic malignancies there is the potential for pharmacokinetic drug-drug interactions given that voriconazole is metabolized through the P450 cytochrome system.

Brazilian guidelines for the management of candidiasis - a joint meeting report of three medical societies: Sociedade Brasileira de Infectologia, Sociedade Paulista de Infectologia and Sociedade Brasileira de Medicina Tropical

Candida infections account for 80% of all fungal infections in the hospital environment, including bloodstream, urinary tract and surgical site infections. Bloodstream infections are now a major challenge for tertiary hospitals worldwide due to their high prevalence and mortality rates. The incidence of candidemia in tertiary public hospitals in Brazil is approximately 2.5 cases per 1000 hospital admissions. Due to the importance of this infection, the authors provide a review of the diversity of the genus Candida and its clinical relevance, the therapeutic options and discuss the treatment of major infections caused by Candida. Each topography is discussed with regard to epidemiological, clinical and laboratory diagnostic and therapeutic recommendations based on levels of evidence.

Candida albicans infections in renal transplant recipients: effect of caspofungin on polymorphonuclear cells

This study aimed to compare the caspofungin immunomodulating activities against Candida albicans on polymorphonuclear cells (PMNs) from renal transplant recipients (RTRs) and healthy subjects (HSs). RTR PMNs showed a significantly reduced fungicidal activity compared with that of HS PMNs. Addition of caspofungin to RTR PMNs significantly potentiated the yeast intracellular killing rate, achieving values similar to those observed for HS PMNs. These data show that caspofungin is suitable for invasive candidiasis treatment in patients with immune system-impaired components.

Mucormycosis: its contemporary face and management strategies

Several countries have seen rising frequencies of mucormycosis among patients with haematological disorders, malignancies, or diabetes mellitus, and among transplant recipients. Growing numbers of immunocompromised hosts, widespread use of antifungal agents inactive against mucormycosis, or other unidentified factors, could be contributing to this situation. The predominant clinical manifestations of mucormycosis vary from host to host. Additionally, risk factors specific to different subgroups have been identified, such as leukaemia, allogeneic haemopoietic stem-cell transplant, voriconazole prophylaxis, diabetes, and malnutrition. We summarise the current state of knowledge of characteristics and risk factors and discuss topical developments in therapeutic methods and strategies in the management of mucormycosis.

Posaconazole prophylaxis in patients with acute myelogenous leukaemia--results from an observational study

Patients with acute myelogenous leukaemia (AML) and neutropenia after chemotherapy are at high risk for life-threatening invasive fungal disease (IFD), in particular, invasive aspergillosis (IA). The aim of the study was to evaluate data on characteristics, risk factors, complications and additional antifungal treatment of patients with AML receiving posaconazole prophylaxis (PP) after chemotherapy in an actual clinical setting. A retrospective single-centre observational study on 40 patients with AML, median age 66 years, was conducted. PP 200 mg three times daily was given routinely. After 76 cycles of remission induction chemotherapy followed by PP, median duration of 31 days (range 6-61 days), no fatal case occurred. The majority of patients had at least one additional risk factor for IFD and during 32 cycles (42.1%), three risk factors were present. During 40 therapy cycles (52.6%), fever of unknown origin occurred. Pneumonia was diagnosed after 23 cycles (30.3%), thereof one case of proven IA (1.3%). PP was interrupted in 25 cycles (32.9%) and was followed by systemic antifungal therapy with different agents, with a median duration 15 days (range: 6-32 days). PP appears to be an effective and well-tolerated protection against IFD for AML patients under natural clinical conditions.

Antifungal drug resistance: do molecular methods provide a way forward?

PURPOSE OF REVIEW

Antifungal drug resistance is a confounding factor that negatively impacts clinical outcome for patients with serious mycoses. Early detection of fungi in blood or other specimens with a rapid assessment of drug susceptibility could improve the survival of patients with invasive disease by accelerating the initiation of appropriate antifungal treatment. Recent years have seen the growth of molecular technology that is ideally suited for fungal identification and assessment of drug resistance mechanisms.

RECENT FINDINGS

Elucidation of the genetic mechanisms responsible for triazole and echinocandin resistance in prominent Candida spp. and Aspergillus spp. provides an opportunity to develop molecular diagnostic platforms suitable for rapid detection of primary and secondary drug resistance. Several highly dynamic and robust amplification/detection methodologies are now available that can provide simultaneous species identification and high fidelity discrimination of resistance alleles.

SUMMARY

Molecular diagnostic platforms are ideal for rapid detection of fungal pathogens and they provide an opportunity to develop in parallel molecular assays that can evaluate antifungal drug resistance.

Amphotericin B-induced nephrotoxicity: characterization of blood and urinary biochemistry and renal morphology in mice

This study was conducted to characterize blood and urinary biochemistry, and renal morphology, after single or 1-week repeated dosing of mice with the polyene macrolide antibiotic, amphotericin B (AMB). AMB was intravenously administered to mice at 2 or 4 mg/kg for the single-dose experiment or once daily at 1 or 2 mg/kg for 1 week for the repeated-dose experiment. The most prominent histopathological findings included necrosis of the tubular epithelial cells in the thick ascending limb of Henle's loop in the renal outer medulla at a single dose of 2 or 4 mg/kg, and the severity of the lesion was dose-dependent. Blood chemistry and urinalysis revealed several changes suggestive of renal dysfunction such as reduction of plasma filtration ability (increases in plasma creatinine and blood urea nitrogen, a decrease in creatinine clearance) and polyuria accompanied with dehydration (decrease in renal water reabsorption, increases in plasma total protein and albumin) at a dose of 4 mg/kg in the single-dose experiment. Among the parameters analyzed, urinary lactate dehydrogenase was the most sensitive and reliable parameter for the prediction of AMB-induced nephrotoxicity in mice. These data provided comprehensive information on the nephrotoxicity of AMB and indicate useful markers for the sensitive detection of AMB-induced renal injury in mice.

Liposomal amphotericin B: a review of its use as empirical therapy in febrile neutropenia and in the treatment of invasive fungal infections

Liposomal amphotericin B (AmBisome) is a lipid-associated formulation of the broad-spectrum polyene antifungal agent amphotericin B. It is active against clinically relevant yeasts and moulds, including Candida spp., Aspergillus spp. and filamentous moulds such as Zygomycetes, and is approved for the treatment of invasive fungal infections in many countries worldwide. It was developed to improve the tolerability profile of amphotericin B deoxycholate, which was for many decades considered the gold standard of antifungal treatment, despite being associated with infusion-related events and nephrotoxicity. In well controlled trials, liposomal amphotericin B had similar efficacy to amphotericin B deoxycholate and amphotericin B lipid complex as empirical therapy in adult and paediatric patients with febrile neutropenia. In addition, caspofungin was noninferior to liposomal amphotericin B as empirical therapy in adult patients with febrile neutropenia. For the treatment of confirmed invasive fungal infections, liposomal amphotericin B was more effective than amphotericin B deoxycholate treatment in patients with disseminated histoplasmosis and AIDS, and was noninferior to amphotericin B deoxycholate in patients with acute cryptococcal meningitis and AIDS. In adults, micafungin was shown to be noninferior to liposomal amphotericin B for the treatment of candidaemia and invasive candidiasis. Data from animal studies suggested that higher dosages of liposomal amphotericin B might improve efficacy; however, in the AmBiLoad trial in patients with invasive mould infection, there was no statistical difference in efficacy between the standard dosage of liposomal amphotericin B 3 mg/kg/day and a higher 10 mg/kg/day dosage, although the standard dosage was better tolerated. Despite being associated with fewer infusion-related adverse events and less nephrotoxicity than amphotericin B deoxycholate and amphotericin B lipid complex, liposomal amphotericin B use is still limited to some extent by these adverse events. Both echinocandins were better tolerated than liposomal amphotericin B. The cost of liposomal amphotericin B therapy may also restrict its use, but further pharmacoeconomic studies are required to fully define its cost effectiveness compared with other antifungal agents. Based on comparative data from well controlled trials, extensive clinical experience and its broad spectrum of activity, liposomal amphotericin B remains a first-line option for empirical therapy in patients with febrile neutropenia and in those with disseminated histoplasmosis, and is an option for the treatment of AIDS-associated cryptococcal meningitis, and for invasive Candida spp. or Aspergillus spp. infections. Amphotericin B, a macrocyclic, polyene antifungal agent, is thought to act by binding to ergosterol, the principal sterol in fungal cell membranes and Leishmania cells. This results in a change in membrane permeability, causing metabolic disturbance, leakage of small molecules and, as a consequence, cell death. In vitro and in vivo studies have shown that liposomal amphotericin B remains closely associated with the liposomes in the circulation, thereby reducing the potential for nephrotoxicity and infusion-related toxicity associated with conventional amphotericin B. Amphotericin B shows very good in vitro activity against a broad spectrum of clinically relevant fungal isolates, including most strains of Candida spp. and Aspergillus spp., and other filamentous fungi such as Zygomycetes. Liposomal amphotericin B has proven effective in various animal models of fungal infections, including those for candidiasis, aspergillosis, fusariosis and zygomycosis. Liposomal amphotericin B also shows immunomodulatory effects, although the mechanisms involved are not fully understood, and differ from those of amphotericin B deoxycholate and amphotericin B colloidal dispersion. In adult patients with febrile neutropenia, intravenous liposomal amphotericin B has nonlinear pharmacokinetics, with higher than dose-proportional increases in exposure being consistent with reticuloendothelial saturation and redistribution of amphotericin B in the plasma compartment. Liposomal amphotericin B is rapidly and extensively distributed after single and multiple doses, with steady-state concentrations of amphotericin B attained within 4 days and no clinically relevant accumulation of the drug following multiple doses of 1-7.5 mg/kg/day. In autopsy tissue, the highest concentrations of the drug were found in the liver and spleen, followed by the kidney, lung, myocardium and brain tissue. Elimination of liposomal amphotericin B, like that of amphotericin B deoxycholate, is poorly understood; its route of metabolism is not known and its excretion has not been studied. The terminal elimination half-life is about 7 hours. No dosage adjustment is required based on age or renal impairment. In several randomized, double-blind trials (n = 73-1095) in adult and/or paediatric patients, liposomal amphotericin B was effective as empirical therapy or as treatment for confirmed invasive fungal infections, including invasive candidiasis, candidaemia, invasive mould infection (mainly aspergillosis), histoplasmosis and cryptococcal meningitis. All agents were administered as an intravenous infusion; the typical dosage for liposomal amphotericin B was 3 mg/kg/day. Treatment was generally given for 1-2 weeks. Participants in trials evaluating empirical therapy had neutropenia and a persistent fever despite antibacterial treatment and had received chemotherapy or undergone haematopoietic stem cell transplantation. As empirical therapy in adult and paediatric patients, liposomal amphotericin B appeared to be as effective as amphotericin B deoxycholate (approximately 50% of patients in each group achieved treatment success) or amphotericin B lipid complex (approximately 40% of liposomal amphotericin B recipients experienced treatment success). Of note, in the first trial, results of the statistical test to determine equivalence between treatments were not reported. In the second trial, efficacy was assessed as an 'other' endpoint. In another trial, caspofungin was shown to be noninferior to liposomal amphotericin B, with approximately one-third of patients in each group experiencing treatment success. Liposomal amphotericin B was significantly more effective than amphotericin B deoxycholate for the treatment of moderate to severe disseminated histoplasmosis in patients with AIDS, with 88% and 64% of patients, respectively, having a successful response. Liposomal amphotericin B was noninferior to amphotericin B deoxycholate for the treatment of cryptococcal meningitis in terms of mycological success. Micafungin therapy was shown to be noninferior to liposomal amphotericin B for the treatment of adult patients with candidaemia or invasive candidiasis. In a substudy in paediatric patients, which was not powered to determine noninferiority, liposomal amphotericin B was as effective as micafungin for the treatment of candidaemia or invasive candidiasis. In this patient population, within each trial, 90% of adult patients and approximately three-quarters of paediatric patients in both treatment groups experienced a successful response. In patients with invasive mould infection (mainly aspergillosis), there was no difference in efficacy between a higher dosage of liposomal amphotericin B (10 mg/kg/day) and the standard dosage (3 mg/kg/day), with 46% and 50% of patients experiencing a favourable overall response. In well designed clinical trials, liposomal amphotericin B was generally at least as well tolerated as other lipid-associated formulations of amphotericin B and better tolerated than amphotericin B deoxycholate in adult and paediatric patients. Compared with other amphotericin B formulations, liposomal amphotericin B treatment was associated with a lower incidence of infusion-related adverse events and nephrotoxicity. A higher than recommended dosage of liposomal amphotericin B (10 mg/kg/day) was associated with an increased incidence of nephrotoxicity compared with the standard dosage (3 mg/kg/day), although the incidence of infusion-related reactions did not differ between treatment groups. In general, liposomal amphotericin B treatment was not as well tolerated as echinocandin therapy in well designed clinical trials. As empirical therapy or for the treatment of confirmed invasive fungal infections in adult patients, liposomal amphotericin B recipients experienced more infusion-related events and nephrotoxicity than caspofungin or micafungin recipients. There was no difference in the incidence of these adverse events between the liposomal amphotericin B and micafungin groups in a study in paediatric patients.

[Clinical use of micafungin for the treatment of invasive candidiasis in critical ill patients]

BACKGROUND

Over the last 30 years a significant increase of Candida spp. invasive disease has been observed in non-neutropenic critical ill patients. Both fluconazole and amphotericin B have been considered first line treatment for invasive (proven and probable) Candida spp. disease, although the mortality rate is still high.

OBJECTIVES

To review the current data on the use of micafungin for the treatment of Candida invasive disease in critical ill patients.

METHODS

The pharmacologic, mycological and clinical properties of micafungin are reviewed based on current published data. The use and efficacy of micafungin for the treatment of Candida invasive disease in critical ill patients is discussed.

RESULTS AND CONCLUSIONS

To reduce the rate of mortality more effective antifungals and pre-emptive treatment strategies are currently warranted. Candins achieve better results for the treatment of invasive Candida disease in non-neutropenic critical ill patients. Micafungin has a good safety profile (similar to fluconazole). Micafungin is a first line drug for the treatment of invasive Candida disease and may be used as a pre- emptive approach followed by a de-escalating strategy with azoles.