Invasive aspergillosis. Disease spectrum, treatment practices, and outcomes. I3 Aspergillus Study Group

Invasive filamentous fungal infections in allogeneic hematopoietic stem cell transplant recipients after recovery from neutropenia: Clinical, radiologic, and pathologic characteristics

Invasive filamentous fungal infection (IFFI) is an important cause of mortality in allogeneic hematopoietic stem cell transplant (HSCT) recipients. We reviewed 22 consecutive cases of IFFI in allogeneic HSCT recipients at Roswell Park Cancer Institute. IFFI was diagnosed after neutrophil recovery in 21 patients (95%). All had received corticosteroids within 1 month prior to IFFI diagnosis. Fourteen (64%) presented with dyspnea, and only 7 (32%) were febrile. Aspergillus species were isolated in 18 (82%) cases. Thirty day mortality after IFFI diagnosis was associated with a higher mean daily dose of corticosteroids (P=0.02) and receiving OKT3 (P=0.01) within 1 month prior to IFFI diagnosis and serum creatinine>2 mg/dl at the time of diagnosis (P=0.004). Histopathologic material from biopsy or autopsy was available in 15 patients (68%). In 8 (53%), the predominant lung histopathology was an acellular coagulative necrosis and hyphal angioinvasion was observed in some of these cases. These findings have generally been observed in neutropenic patients but not in non-neutropenic HSCT recipients. The predominance of coagulative necrosis in our series may reflect the high doses of corticosteroids used to treat graft-versus-host disease (GVHD), which may have disabled leukocyte trafficking and hyphal killing.

Peritonitis caused by Aspergillus sydowii in a patient undergoing continuous ambulatory peritoneal dialysis

We describe a patient who received continuous ambulatory peritoneal dialysis and developed catheter-related peritonitis caused by Aspergillus sydowii. Identification of A. sydowii was confirmed by the sequence analysis of the ribosomal RNA genes. The patient remained well after removal of the peritoneal catheter without administration of any anti-fungal agent.

New findings and unique aspects in pediatric aspergillosis

There is a paucity of specific data on pediatric invasive aspergillosis. While the underlying predisposing patient diseases and treatments differ in children and adults, it also appears that there is a heterogeneity of invasive aspergillosis disease that extends to children. These aspects extend in some reports to the Aspergillus spp. distribution as well as the fundamental pathophysiology of the disease in different age groups. For instance, the newer diagnostic tools hold great promise for adult patients but it appears that they have limited usefulness in children. Only through dedicated pediatric study will clinicians fully discover the nuances and unique findings in children with this deadly disease.

The future of animal models of invasive aspergillosis

The diagnosis of invasive aspergillosis remains very difficult, coupled with limited treatment options. Animal models have been utilized to evaluate both the diagnosis and treatment of infection and to assess the pathogenicity and virulence of the organism. However, animal models have not been standardized and have been used in only a limited fashion for genomic evaluation in this disease. Extensive efforts are underway to expand significantly the Aspergillus genomic information. Thus, the standardization of animal models of invasive aspergillosis is critical to create a unified platform to enhance evaluation of newer genomic information and allow assessment of pathogenicity and virulence factors. Proposed models, supported by a recently awarded National Institutes of Health/National Institute of Allergy and Infectious Diseases contract, will be developed in close interaction with the extended Aspergillus community (including academia and industry) to answer key questions in this disease. The goal of this work is to provide the framework to evaluate genomic targets in animal models in order to improve the diagnosis and treatment of invasive aspergillosis that will ultimately result in improved outcomes of patients with this frequently fatal infection.

Aspergillosis in the CLEAR outcomes trial: working toward a real-world clinical perspective

Aspergillosis is a potentially lethal infection of immunocompromised patients. Until 10 years ago, antifungal therapy was largely limited to amphotericin B deoxycholate. Perceived poor response rates and inherent toxicities with amphotericin B deoxycholate were a major stimulus for the development of newer antifungals, including lipid-formulated amphotericin B, broad spectrum azoles, and echinocandins. Response rates to antifungals are highly dependent on the underlying diagnosis and degree of immune suppression of the patient. Patients at highest risk of death from aspergillosis also have very high mortality rates from other causes as well. Outcomes reported in historical literature reviews fail to distinguish between overall mortality and death attributable to aspergillosis. While this distinction can often be difficult to assess clinically, the net effect is to underestimate the therapeutic success rates of antifungals. The CLEAR (Collaborative Exchange of Antifungal Research) project started as a post approval survey to monitor clinical use of amphotericin B lipid complex (ABLC). The scope of the CLEAR project included collection of clinical data to assess outcomes in patients with invasive fungal infections treated with ABLC. Clinical data from more than 3500 patients were entered into the CLEAR database. Outcomes were assessed for 509 patients with documented aspergillosis and complete data records. Overall response rate was 63% (cured/improved/stable) with site-specific response rates of 61%, 59%, and 32% for lung, sinus, and central nervous system infections, respectively. Solid organ transplant recipients had higher response rates than patients with hematological malignancies. Bone marrow transplant recipients had the lowest response rates. Clinical response rates with ABLC reported in the CLEAR trial are higher than response rates reported for amphotericin B deoxycholate in other trials. Since it is unlikely we will see any new comparative Phase III trials for aspergillosis, CLEAR-type outcome studies will prove useful for the foreseeable future to guide clinical management of aspergillosis.

Antifungal combination therapy: clinical potential

Combination antifungal therapy has been an area of research and clinical interest since systemic antifungals became available decades ago. In vitro and clinical data were generated for some of the more common invasive fungal infections, especially candidiasis, but until very recently few clinical studies were performed. The first invasive fungal infection to be examined in clinical trials with adequate statistical power was cryptococcal meningitis and several of these trials stand out as classical studies in the clinical evaluation of combination antifungal therapy. More recently, since the availability of the newer antifungal agents, including the echinocandins and extended-spectrum triazoles, there has been a growing interest in examining combination antifungal therapy for invasive fungal disease, especially invasive aspergillosis. This is by no means a comprehensive review of all existing experimental data. Instead, the focus is on the clinical data that have been generated to date and on providing insights into potential future clinical directions. For instance, recent clinical data for cryptococcosis confirm that amphotericin B plus flucytosine is the most active combination for patients with cryptococcal meningitis. A recently completed clinical trial in candidaemia suggests a trend towards improved outcomes among patients receiving amphotericin B plus fluconazole versus fluconazole alone. In aspergillosis, several experimental models suggest benefit of a variety of antifungal combinations, but have not been confirmed in prospective clinical trials. Ultimately, the goal is to provide the reader with a comprehensive but useful review to this complicated and often confusing therapeutic dilemma.

Recent developments in the management of invasive fungal infections in patients with hematological malignancies

Despite recent advances in the last decade, invasive fungal infections are still associated with a high morbidity and mortality. Invasive fungal infections constitute severe infectious complications in patients with hematological malignancies receiving myelosuppressive chemotherapy or sustained immunosuppression after allogeneic transplant regimens. Following a long period of stagnation, considerable progress has been made during the last 5 years in non-culture-based diagnostics and in the treatment of invasive fungal infections. This review highlights recent developments in the epidemiology, diagnosis, and treatment in the context of state-of-the-art management of invasive fungal infections in cancer patients.

Anti-Aspergillus fumigatus efficacy of pentraxin 3 alone and in combination with antifungals

The collectin pentraxin 3 (PTX3) is an essential component of host resistance to pulmonary aspergillosis. Here we examined the protective effects of administration of PTX3 alone or together with deoxycholate amphotericin B (Fungizone) or liposomal amphotericin B (AmBisome) against invasive aspergillosis in a murine model of allogeneic bone marrow transplantation. PTX3, alone or in combination with the polyenes, was given intranasally or parenterally either before, in concomitance with, or after the intranasal infection with Aspergillus fumigatus conidia. Mice were monitored for resistance to infection and parameters of innate and adaptive T-helper immunity. The results showed the following: (i) complete resistance to infection and reinfection was observed in mice treated with PTX3 alone; (ii) the protective effect of PTX3 was similar or superior to that observed with liposomal amphotericin B or deoxycholate amphotericin B, respectively; (iii) protection was associated with accelerated recovery of lung phagocytic cells and T-helper-1 lymphocytes and concomitant decrease of inflammatory pathology; and (iv) PTX3 potentiated the therapeutic efficacy of suboptimal doses of either antimycotic drug. Together, these data suggest the potential therapeutic use of PTX3 either alone or as an adjunctive therapy in A. fumigatus infections.

What is the clinical significance of positive blood cultures with Aspergillus sp in hematopoietic stem cell transplant recipients? A 23 year experience

Hematopoietic stem cell (HSC) transplantation is the most frequent underlying predisposing condition to invasive aspergillosis. However, the significance of positive blood culture with Aspergillus sp in this particular population remains uncertain. We retrospectively reviewed all blood cultures performed in 1453 patients who received HSC transplant at our institution between 1980 and 2002. We identified 19 patients with positive blood cultures with Aspergillus sp. Only one of these patients had clinical, histologic or microbiologic evidence of invasive aspergillosis. Thus, even in a population at highest risk for invasive aspergillosis, positive blood cultures with Aspergillus sp remain unusual, and cannot be readily associated with invasive aspergillosis. A case by case assessment by treating physicians of the clinical and radiologic parameters should be systematically made to establish the significance of aspergillemia. Single bottle positivity, obtained with the lysis-centrifugation blood culture system, is a common indicator of pseudoaspergillemia.

Efficacy and safety of caspofungin for treatment of invasive aspergillosis in patients refractory to or intolerant of conventional antifungal therapy

BACKGROUND

Invasive aspergillosis (IA) is an important cause of morbidity and mortality among immunocompromised patients. Echinocandins are novel antifungal molecules with in vitro and in vivo activity against Aspergillus species.

METHODS

We investigated the efficacy and safety of caspofungin in the treatment of IA. Ninety patients with IA who were refractory to or intolerant of amphotericin B, lipid formulations of amphotericin B, or triazoles were enrolled to receive caspofungin.

RESULTS

Efficacy was assessed for 83 patients who had infection consistent with definitions of IA and who received >or=1 dose of study drug. Common underlying conditions included hematologic malignancy (48% of patients), allogeneic blood and marrow transplantation (25% of patients), and solid-organ transplantation (11% of patients). Seventy-one patients (86%) were refractory to and 12 patients (14%) were intolerant of previous therapy. A favorable response to caspofungin therapy was observed in 37 (45%) of 83 patients, including 32 (50%) of 64 with pulmonary aspergillosis and 3 (23%) of 13 with disseminated aspergillosis. Two patients discontinued caspofungin therapy because of drug-related adverse events. Drug-related nephrotoxicity and hepatotoxicity occurred infrequently.

CONCLUSION

Caspofungin demonstrated usefulness in the salvage treatment of IA.

Design Issues in a Prospective Randomized Double-Blinded Trial of Prophylaxis with Fluconazole versus Voriconazole after Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

Aspergillus infections pose the toughest infectious challenges to the clinician caring for hematopoietic cell transplant recipients. About 15% of patients become infected, with a case fatality rate of approximately 65%. To date, no effective prophylactic strategies have been developed.

METHODS

Voriconazole, a recently licensed extended-spectrum azole, with demonstrated efficacy against aspergillus, is currently being tested as a potential prophylactic agent against aspergillus and other invasive fungal infections. Logistic issues--such as patient selection, choice of comparator, blinding of study drugs, duration of study drug administration, and how to handle empirical amphotericin B for possible invasive fungal infections--and analytic concerns, including choice and definition of the primary end point and the potential confounding effect of informative censoring (as a result of noninfectious events), were considered in the design of the clinical trial.

RESULTS

The trial is now under way, with a projected 3-year enrollment period.

CONCLUSIONS

Each design decision shaped the trial in a way that permitted certain questions to be answered while not allowing others to be addressed. Once completed, the trial's results must be interpreted in light of these design details.

The Design of Clinical Trials That Evaluate Antifungal Prophylaxis and Combination Therapy: Introduction and Overview

On 8 February 2003, the second in a series of meetings in honor of John E. Bennett, M.D., was convened in New York City. A report from the previous meeting was published in 2003. The goal of this second meeting was to discuss the design of clinical trials in prophylaxis and combination therapy. This supplement presents 12 articles by leading clinicians who are currently active in trials in this area and presents a current view of the unmet needs and challenges.

Successful treatment of brain aspergillosis with voriconazole

Until recently, brain aspergillosis was almost always fatal, with a response rate to amphotericin B of < 10%. This study describes a retrospective analysis of eight consecutive cases of brain aspergillosis. All patients were immunosuppressed and five required mechanical ventilation. Antifungal treatment included amphotericin B (n = 7), itraconazole (n = 3), voriconazole (n = 2) and flucytosine (n = 1). Three (38%) patients survived following prolonged azole therapy after initial amphotericin B treatment, combined with a reduction in their immunosuppressive treatment. The prognosis of brain aspergillosis might be improved if immunosuppression could be reduced and prolonged oral azole therapy used.

Efficacy of voriconazole plus amphotericin B or micafungin in a guinea-pig model of invasive pulmonary aspergillosis

The efficacy of voriconazole in combination with amphotericin B or micafungin was studied in a transiently neutropenic guinea-pig model of invasive pulmonary aspergillosis. Guinea-pigs treated with the antifungal drugs, alone or in two-drug combinations, had an improved survival rate and reduced fungal burden in the lungs compared to untreated control animals. The efficacy of monotherapy and combination therapy was similar; activity was neither enhanced nor reduced with the two-drug combinations. Further studies of efficacy, dosing and optimal regimens for antifungal combinations are warranted.

A new era of antifungal therapy

Invasive fungal infections pose major management problems for clinicians caring for hematopoietic cell transplant patients. Two major fungal genera, Candida and Aspergillus, account for most fungal infections. Rates of systemic Candida infection range from 15% to 25%, mostly in the pre-engraftment period. Prophylaxis by fluconazole has dramatically reduced the frequency of early Candida infections. Caspofungin has recently been shown to offer an excellent alternative to amphotericin B (with less toxicity) or fluconazole (with a broader spectrum) for therapy of systemic Candida infections. Aspergillus infections occur in 15% to 20% of allogeneic hematopoietic cell transplant patients, most frequently in the post-engraftment period; they are associated with a severe diminution of cell-mediated immune responses by graft-versus-host disease and prolonged corticosteroid use. Voriconazole, a recently introduced broad-spectrum azole, has excellent activity against Aspergillus and is generally well tolerated. Voriconazole currently offers the best prospect for success and tolerance as a first-line treatment for aspergillosis. Second-line therapies include lipid formulations of amphotericin B, caspofungin, or intravenous itraconazole. Unfortunately, early initiation of therapy for aspergillosis is frequently not possible because of inaccurate diagnostics. One new diagnostic, the galactomannan assay, has recently been approved, and others are in development; these offer promise for earlier diagnosis without the need for invasive procedures. It is hoped that these new therapies and new diagnostics will usher in a new era of antifungal therapy.

Combinations of antifungal agents in therapy--what value are they?

Concurrent or sequential antifungal treatment for invasive mycoses has been typically considered as an option to improve results of monotherapy. However, data on the efficacy of combination therapy are sparse and consist largely of results from studies in vitro and experimental animal models. These studies have yielded controversial results depending on the criteria used to evaluate the antifungal interaction. Several combinations that showed synergy in vitro failed to do so in animal models. Overall, apart from cryptococcal infections, combined antifungal therapy is not significantly better than monotherapy in terms of clinical efficacy. It is questionable whether combination therapy should be used in most cases as there is a lack of evidence from well-designed clinical trials. However, combination therapy could be an alternative to monotherapy for patients with invasive infections that are difficult to treat, such as those due to multi-resistant species and for those who fail to respond to standard treatment.

Combination Antifungal Therapy for Invasive Aspergillosis

BACKGROUND

Aspergillosis therapy with amphotericin, azoles, or echinocandins is associated with substantial mortality, ranging from 30% to 80%, depending on the stage of infection and the host's underlying disease. The results of in vitro studies and animal models suggest that combination therapy with azoles and echinocandins may have additive activity against Aspergillus species.

METHODS

We evaluated the outcomes of patients with aspergillosis who experienced failure of initial therapy with amphotericin B formulations and received either voriconazole (n=31) or a combination of voriconazole and caspofungin (n=16) for salvage therapy.

RESULTS

The combination of voriconazole and caspofungin was associated with improved 3-month survival rate, compared with voriconazole alone (hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.17-1.1; P=.048). In multivariable models, salvage therapy with the combination of voriconazole and caspofungin was associated with reduced mortality, compared with therapy with voriconazole (HR, 0.28; 95% CI, 0.28-0.92; P=.011), independent of other prognostic variables (e.g., receipt of transplant and type of conditioning therapy). The probability of death due to aspergillosis was lowest in patients who received the combination regimen.

CONCLUSIONS

Randomized trials are warranted to determine whether this combination should be used as primary therapy for aspergillosis.

Emerging fungal resistance

There has been an increase in systemic fungal infections over the past several decades, partially because of an increasing number of critically ill patients, surgical procedures, and immunosuppressive therapies, as well as the use of more invasive diagnostic and therapeutic medical procedures. Concomitant with this increase in infections has been the increase in azole-resistant Candida species and opportunistic molds with intrinsic resistance to many of the currently available antifungal agents. This review focuses on antifungal resistance, with emphasis on emerging resistance patterns and emerging fungi that are intrinsically resistant to antifungal agents.

Oxidative and amphotericin B-mediated cell death in the opportunistic pathogen Aspergillus fumigatus is associated with an apoptotic-like phenotype

When protoplasts of the opportunistic fungal pathogen Aspergillus fumigatus were treated with low but toxic levels of hydrogen peroxide (0.1 mM) or amphotericin B (0.5 microg ml(-1)), loss of cell viability and death were associated with a number of phenotypic changes characteristic of apoptosis. The percentage of protoplasts staining positive with annexin V-FITC, an indicator of the externalization of phosphatidylserine and an early marker of apoptosis, rose to approximately 55 % within 1 h. This was followed by a similar increase in apoptotic DNA fragmentation detected by the TUNEL assay, and led to a loss of cell permeability and death in approximately 90 % of protoplasts, as indicated by the uptake of propidium iodide. The development of an apoptotic phenotype was blocked when protoplasts were pre-treated with the protein synthesis inhibitor cycloheximide, indicating active participation of the cell in the process. However, no significant activity against synthetic caspase substrates was detected, and the inclusion of the cell-permeant broad-spectrum caspase inhibitor Z-VAD-fmk did not block the development of the apoptotic-like phenotype. Higher concentrations of H(2)O(2) (1.8 mM) and amphotericin B (1 microg ml(-1)) caused protoplasts to die without inducing an apoptotic phenotype. As predicted, the fungistatic antifungal agent itraconazole, which inhibits growth without causing immediate cell death, did not induce an apoptotic-like phenotype.

Prospective clinical evaluation of lower cut-offs for galactomannan detection in adult neutropenic cancer patients and haematological stem cell transplant recipients

The recent advent of an improved commercial serum enzyme-linked immunosorbent assay (ELISA) for the detection of circulating galactomannan (GM), a major constituent of Aspergillus cell walls, has contributed to the diagnosis of invasive aspergillosis (IA) in many haematology and transplant centres. However, the optimal threshold for positivity remains a matter of debate. We prospectively evaluated the impact of lowering the cut-off in 124 neutropenic episodes with a high pretest probability for IA. Two new cut-off points, lower than previously accepted, are proposed: (a) a 'static' cut-off at 0.8 and (b) a 'dynamic' cut-off at 0.5. A single assay with an optical density (OD) index > or = 0.8 warrants the initiation of anti-Aspergillus therapy. A further lowering of the 'static' threshold seems not clinically feasible given the drop in positive predictive value (PPV). However, the demonstration of at least two sequential sera with an OD > or = 0.5 ('dynamic' threshold) increased the specificity and the PPV to 98.6% and the efficiency to 98%. Applying both cut-offs to a subgroup of 21 'possible' fungal infections further identified and upgraded six cases of IA. However, the clinical benefit of lower cut-offs (particularly for earlier diagnosis) depends upon the kinetics of antigenaemia and the intensity of serum sampling.

Infections Due to Aspergillus terreus: A Multicenter Retrospective Analysis of 83 Cases

Current in vitro and in vivo data indicate that invasive aspergillosis due to Aspergillus terreus is resistant to treatment with amphotericin B. Because little clinical data are available to guide therapy, we performed a retrospective cohort study of cases of invasive A. terreus infections from 1997-2002 to determine whether the use of voriconazole, compared with use of other antifungal therapies, led to an improved patient outcome. We analyzed a total of 83 cases of proven or probable invasive A. terreus infection (47% and 53%, respectively). A total of 66.3% of patients (55 of 83) died during management of IA, with 55.8% mortality (19 of 34 patients) in the voriconazole group and 73.4% mortality (36 of 49) in the group that received therapy with other antifungals. By use of Cox proportional hazards modeling, decreased mortality at 12 weeks was observed in those patients who received voriconazole (hazard ratio, 0.29; 95% CI, 0.15-0.56). Voriconazole is likely to be a better treatment choice for A. terreus infection than is a polyene.

Determination of fungicidal activities against yeasts and molds: lessons learned from bactericidal testing and the need for standardization

In certain unique clinical settings, the ability of the antimicrobial agent administered to kill the pathogen outright may be quite important. These situations invariably involve infection of a site not easily accessed by host defenses and/or of a structure with essential anatomic or physiologic function such as the heart (endocarditis), central nervous system (meningitis), or bone (osteomyelitis). Likewise, infections in immunosuppressed hosts, especially those who are neutropenic, are often thought to require microbicidal therapy. Proof of the cidal nature of an antimicrobial agent in vitro is tedious, complex, and fraught with error. Although several methods for assessing in vitro bactericidal activity have been standardized (NCCLS M26-A and M21-A), the clinical relevance of these determinations is questionable and the tests are performed infrequently in most laboratories. Most of the clinical data supporting the need for microbicidal therapy and testing have focused on bacterial infections. However, given the fact that most serious fungal infections occur in profoundly immunosuppressed individuals, it is generally assumed that a cidal regimen would be preferable in that setting as well. In view of this clinical concern and the perceived need to assess the fungicidal activity of a variety of agents, we considered that it would be useful to review what is known about the issues and problems in assessing bactericidal activity and the clinical utility of such measurements. Following this review, we discuss the issue of how one defines fungicidal activity in vitro and in vivo and how feasible it might be to determine the fungicidal activity of organism-drug combinations for purposes of both drug development and clinical care. Proposed methods for fungal time-kill determinations and minimal fungicidal concentration determinations are also discussed.

Toward more effective antifungal therapy: the prospects of combination therapy

The availability of new antifungal agents with unique mechanisms of action and improved tolerability has widened the possibilities for the use of combination antifungal therapy for difficult-to-treat opportunistic mycoses. However, the use of this therapy is largely governed by empiricism, especially in patients with invasive mould infections, for whom there is a tremendous need to improve outcomes. Because of the difficulties associated with the design and conduct of clinical trials of combination antifungal therapy for opportunistic mycoses, the majority of the studies evaluating antifungal combinations are still performed in the laboratory or using animal models of infection. However, the methods used to assess combined antifungal effects in vitro and in animals are poorly standardized, and there is little evidence that data generated from these studies can be translated in treating human mycotic infections. Despite the empiricism of combination antifungal therapy, certain principles help guide the use and study of these regimens.

Efficacy, safety, and plasma pharmacokinetics of escalating dosages of intravenously administered ravuconazole lysine phosphoester for treatment of experimental pulmonary aspergillosis in persistently neutropenic rabbits

Ravuconazole is a new antifungal triazole with broad-spectrum activity and a long half-life in plasma. We studied the antifungal efficacy, safety, and pharmacokinetics of ravuconazole lysine phosphoester in escalating dosages for the treatment of invasive pulmonary aspergillosis due to Aspergillus fumigatus in persistently neutropenic rabbits. Treatment groups consisted of rabbits treated with ravuconazole at 2.5 (RVC2.5), 5 (RVC5), and 10 (RVC10) mg/kg of body weight/day, rabbits treated with amphotericin B (AMB) at 1 mg/kg/day, or untreated controls. There was a dose-dependent reduction of pulmonary residual fungal burden (CFU per gram) in RVC5-, RVC10-, and AMB-treated rabbits in comparison to untreated controls (P < 0.01, P < 0.001, and P < 0.01, respectively). These findings correlated with progressive galactomannan antigenemia in untreated controls and the RVC2.5-treated rabbits, a lower galactomannan index (GMI) in RVC5- and RVC10-treated rabbits, and a similarly low GMI in AMB-treated rabbits (P < 0.01). Rabbits treated with RVC5, RVC10, and AMB also showed a reduction of organism-mediated pulmonary injury, as measured by infarct scores and lung weights, in comparison to untreated controls (P < 0.001). These results were supported by decreased pulmonary infiltrates detected by computed tomography in RVC5- and RVC10-treated rabbits in comparison to untreated controls (P < 0.05). Survival throughout the entire study was achieved in 95% of RVC5-treated rabbits (P < 0.001), 85% of RVC10-treated rabbits (P < 0.001), and 50% of AMB-treated rabbits (P < 0.05) in comparison to none of the untreated controls. Ravuconazole showed linear plasma pharmacokinetics and a large volume of distribution while maintaining concentrations in plasma above the MIC throughout the dosing interval. There was no evidence of hepatotoxicity or nephrotoxicity among ravuconazole-treated animals. Intravenously administered ravuconazole lysine phosphoester showed dose-dependent efficacy and an excellent safety profile for the treatment of invasive pulmonary aspergillosis in persistently neutropenic rabbits.

History of the development of azole derivatives

Until the 1940s, relatively few agents were available for the treatment of systemic fungal infections. The development of the polyene antifungals represented a major advance in medical mycology. Although amphotericin B quickly became the mainstay of therapy for serious infections, its use was associated with infusion-related side-effects and dose-limiting nephrotoxicity. The continued search for new and less toxic antifungals led to the discovery of the azoles several decades later. Ketoconazole, the first available compound for the oral treatment of systemic fungal infections, was released in the early 1980s. For almost a decade, ketoconazole was regarded as the drug of choice in nonlife-threatening endemic mycoses. The introduction of the first-generation triazoles represented a second major advance in the treatment of fungal infections. Both fluconazole and itraconazole displayed a broader spectrum of antifungal activity than the imidazoles and had a markedly improved safety profile compared with amphotericin B and ketoconazole. Despite widespread use, however, these agents became subject to a number of clinically important limitations related to their suboptimal spectrum of activity, the development of resistance, the induction of hazardous drug-drug interactions, their less than optimal pharmacokinetic profile (itraconazole capsules), and toxicity. In order to overcome these limitations, several analogues have been developed. These so-called 'second-generation' triazoles, including voriconazole, posaconazole and ravuconazole, have greater potency and possess increased activity against resistant and emerging pathogens, in particular against Aspergillus spp. If the toxicity profile of these agents is comparable to or better than that of the first-generation triazoles and drug interactions remain manageable, then these compounds represent a true expansion of our antifungal arsenal.

Les aspergilloses cérébrales

INTRODUCTION

The brain is almost always a localization of invasive aspergillosis, after hematogenous spread from pulmonary aspergillosis. Brain aspergilosis is not rare and is one of the worst prognosis factors of invasive aspergillosis.

STATE OF ART

The incidence of this severe mycosis is currently on the rise due to the development of major immunosuppressive treatments. Brain aspergillosis is noteworthy for its vascular tropism, leading to infectious cerebral vasculitis, mainly involving thalamoperforating and lenticulostriate arteries, with a high frequency of thalamic or basal nuclei lesions. Extra-neurologic features that suggest this diagnosis are: i) risk factors for invasive aspergillosis (major or prolonged neutropenia, hematologic malignancies, prolonged corticosteroid treatment, bone marrow or solid organ transplant, AIDS); ii) persistent fever not responding to presumptive antibacterial treatment; iii) respiratory signs (brain aspergillosis is associated with pulmonary aspergillosis in 80 to 95 p. 100 of cases). Perspectives. Two recent major improvements in brain aspergillosis management must be outlined: i) for diagnostic purposes, the development of testing for Aspergillus antigenemia (a non-invasive procedure with good diagnostic value for invasive aspergillosis); ii) for therapeutic purposes, the demonstration that voriconazole is better than amphotericin B in terms of clinical response, tolerance and survival, for all types of invasive aspergillosis, the benefit being probably even greater in case of brain aspergillosis because of the good diffusion of voriconazole into the central nervous system.

CONCLUSIONS

Brain aspergillosis is a severe emerging opportunistic infection for which diagnostic and therapeutic tools have recently improved. Thus, this diagnostic must be suspected early, especially in the immunocompromised patient, in the event of respiratory symptoms and when the brain lesions are localized in the central nuclei and the thalamus.

Activity of posaconazole combined with amphotericin B against Aspergillus flavus infection in mice: comparative studies in two laboratories

Posaconazole and/or amphotericin B was given to mice pretreated with a steroid and then infected by inhalation of Aspergillus flavus conidia. Two laboratories conducted studies using almost identical protocols to evaluate both survival and lung tissue burdens 8 days after infection. The results of the in vivo studies performed at both laboratories were consistent. We found that (i). up to 5 mg of amphotericin B per kg of body weight was poorly effective in treating invasive aspergillosis; (ii). posaconazole at 2 or 10 mg/kg/dose prolonged survival and reduced lung tissue CFU; and (iii). there was generally no antagonistic interaction of the drugs in combination, even when the experiments were designed to maximize the likelihood of antagonism. These studies do not confirm the antagonistic interaction of triazoles and polyenes reported by others.

Guidelines for the use of antifungal agents in the treatment of invasiveCandidaand mould infections

ABSTRACT Treatment of invasive fungal infections is increasingly complex. Amphotericin B deoxycholate has long been the mainstay of treatment. However, there has been increasing recognition of both the propensity for nephro-toxicity in haematology, transplant and intensive care patients as well as its adverse impact on morbidity and mortality. This has coincided with the availabilty of newer, and in certain settings, more effective antifungal agents. Although the newer agents clearly cause less nephrotoxicity than amphotericin B, drug interactions, hepatic effects and unique side-effects need to be considered. The spectrum of the newer triazoles and echinocandins varies, highlighting the importance of accurate identification of the causative organism where possible. Consensus Australian guidelines have been developed to assist clinicians with treatment choices by reviewing the current evidence for the efficacy, the toxicity and the cost of these agents.

Risk factors of invasive aspergillosis after heart transplantation: protective role of oral itraconazole prophylaxis

The study was designed to identify a subset of heart transplant (HT) recipients who could benefit from the administration of targeted antifungal prophylaxis and to evaluate the efficacy of oral itraconazole as the preventive drug. We have analyzed the risk factors for invasive aspergillosis (IA) in our entire population of HT recipients (1988-2002) and also the role of oral itraconazole prophylaxis that was provided to all patients since 1995 [400 mg q.d. of itraconazole oral (PO) for 3-6 months]. There were 24 cases of IA. Our main results indicate that the independent risk factors for IA after heart transplantation are: re-operation (RR 5.8; 95% CI 1.8-18, p=0.002), cytomegalovirus (CMV) disease (RR 5.2; 95% CI 2-13.9, p=0.001), post-transplant hemodialysis (RR 4.9; 95% CI 1.2-18, p=0.02), and the existence of an episode of IA in the HT program 2 months before or after the transplantation date (RR 4.6; 95% CI 1.5-14.4, p=0.007). Itraconazole prophylaxis showed an independent protective value against developing IA (RR 0.2; 95% CI 0.07-0.9, p=0.03) and also determined a significantly prolonged 1-year survival (RR 0.5; 95% CI 0.3-0.8, p=0.01). We believe that antifungal prophylaxis in heart transplant patients should be offered at least to patients with one or more of these predisposing conditions.

Invasive aspergillosis in patients with hematologic malignancies

Invasive aspergillosis is an increasingly common and often fatal opportunistic fungal infection in patients with hematologic malignancies. Prolonged and profound neutropenia remains a key risk factor for the development of invasive aspergillosis. However, qualitative deficiencies in host immune responses resulting from prolonged corticosteroid therapy, graft-versus-host disease, and cytomegalovirus infection are important risk factors for the recurrence and progression of Aspergillus infections after bone marrow recovery. Early diagnosis of invasive aspergillosis remains a challenge, and few tools are available for monitoring its course once the diagnosis is established. Even with the recent introduction of new antifungal therapies, mortality in patients with invasive aspergillosis remains high, and uniformly effective prophylaxis or preemptive therapeutic strategies are lacking. Strategies such as combination antifungal therapy and immunotherapy often are used as first-line treatment approaches in patients with documented invasive aspergillosis despite a paucity of clinical trial data. Recent advances in our understanding of the epidemiology, pathogenesis, and treatment of invasive aspergillosis in patients with hematologic malignancies are reviewed. The problems and controversies associated with defining optimal treatment strategies for invasive aspergillosis in this heavily immunocompromised population are highlighted.

Aspergillus niger infection in patients with haematological diseases: a report of eight cases. Fallbericht. Aspergillus niger-Infektionen bei Patienten mit hamatologischen Erkrankungen

In this paper we analysed clinical, laboratory characteristics and outcome of patients with haematological diseases who developed an Aspergillus niger infection, in a multicentre study involving 14 Italian Haematological Divisions during a 10-year period. The study recorded 194 consecutive microbiologically documented aspergilloses, eight of which (4%) were due to A. niger, and were observed only in five of the participating centres. The primary localization of infection was lung in seven cases and paranasal sinus in one case. Seven patients died at the end of follow-up. The death was mainly attributable to A. niger progression in six of them. Our study that collected the largest number of cases of A. niger infection in haematological malignancies confirms that this infrequent complication is characterized by a high mortality rate.

Thymosin alpha 1 activates dendritic cells for antifungal Th1 resistance through toll-like receptor signaling

Dendritic cells (DCs) show a remarkable functional plasticity in the recognition of Aspergillus fumigatus and orchestrate the antifungal immune resistance in the lungs. Here, we show that thymosin alpha 1, a naturally occurring thymic peptide, induces functional maturation and interleukin-12 production by fungus-pulsed DCs through the p38 mitogen-activated protein kinase/nuclear factor (NF)-kappaB-dependent pathway. This occurs by signaling through the myeloid differentiation factor 88-dependent pathway, involving distinct Toll-like receptors. In vivo, the synthetic peptide activates T-helper (Th) cell 1-dependent antifungal immunity, accelerates myeloid cell recovery, and protects highly susceptible mice that received hematopoietic transplants from aspergillosis. By revealing the unexpected activity of an old molecule, our finding provides the rationale for its therapeutic utility and qualify the synthetic peptide as a candidate adjuvant promoting the coordinated activation of the innate and adaptive Th immunity to the fungus.

Comparison of Etest with modified broth microdilution method for testing susceptibility of Aspergillus spp. to voriconazole

We compared the Etest with a broth microdilution method, performed according to a modified National Committee for Clinical Laboratory Standards guideline (M38-A), for determining the in vitro susceptibility of 77 isolates of Aspergillus spp. (26 A. fumigatus, 21 A. flavus, 10 A. terreus, 9 A. niger, 5 A. nidulellus, 4 A. glaucus, and 2 A. flavipes isolates). Overall, there was 92.2% agreement between both methods when Etest MICs were read at 24 h and 83.1% agreement when both methods were read at 48 h. When Etest MICs were read at 24 h, the agreement was >90% for all species tested except for A. fumigatus (84.6%). When Etest MICs were read at 48 h, the agreement ranged from 50 to 100%. The poorest agreement was seen with A. glaucus (50%) and A. fumigatus (65%). Where a discrepancy was observed between Etest and the reference method, the Etest MIC was generally higher. The Etest appears to be a suitable alternative procedure for testing the susceptibility of Aspergillus spp. to voriconazole.

Salvage therapy with voriconazole for invasive fungal infections in patients failing or intolerant to standard antifungal therapy

BACKGROUND

Invasive fungal infections (IFI), particularly those caused by Aspergillus and other angioinvasive molds, are associated with an excessive mortality despite therapy.

METHODS

Voriconazole was prescribed on a compassionate basis to patients with IFI who were intolerant to or who had progressed despite standard therapy. Outcome was determined by protocol-based criteria as established by the consensus definitions (complete response [CR], partial response [PR], stable disease, failure, and intolerance).

RESULTS

Forty-five patients were enrolled in a compassionate release program (29 [64%] because of failure of response to standard therapy), between 1998 and 2002. Of the 45 patients enrolled, 35 (78%) had invasive Aspergillus, 3 (7%) had Fusarium, and 2 (4%) had Scedosporium infections. Underlying illnesses were as follows: 13 (29%) solid-organ transplant (SOT), 11 (24%) BMT, and 7 (13%) hematologic malignancy. Site of infection was as follows: 26 (58%) pulmonary, 9 (20%) disseminated, 5 (11%) central nervous system (CNS), and 3 (7%) sinus. Overall response rates were as follows: 9 (20%) CR, 17 (38%) PR, 15 (33%) failure, and 4 (9%) intolerant. Seven of the eight (88%) patients with sinus or CNS disease demonstrated stabilization of the IFI. The median duration of voriconazole therapy was 79 days with 9 (20%) patients receiving over 1 year of therapy. Nine thousand one hundred twenty-eight days of therapy were given with only four serious adverse events in two cases considered possibly or probably drug related.

CONCLUSIONS

In this population of severely immunocompromised patients with life-threatening IFI who have failed or were intolerant to standard antifungal therapy, voriconazole demonstrated substantial efficacy and an acceptable level of toxicity.

Use of turbidimetric growth curves for early determination of antifungal drug resistance of filamentous fungi

A previously described microbroth kinetic system (J. Meletiadis, J. F. Meis, J. W. Mouton, and P. E. Verweij, J. Clin. Microbiol. 39:478-484, 2001) based on continuous monitoring of changes in the optical density of fungal growth was used to describe turbidimetric growth curves of different filamentous fungi in the presence of increasing concentrations of antifungal drugs. Therefore, 24 clinical mold isolates, including Rhizopus oryzae, Aspergillus fumigatus, Aspergillus flavus, and Scedosporium prolificans, were tested against itraconazole, terbinafine, and amphotericin B according to NCCLS guidelines. Among various parameters of the growth curves, the duration of the lag phase was strongly affected by the presence of antifungal drugs. Exposure to increasing drug concentrations resulted in prolonged lag phases of the turbidimetric growth curves. The lag phases of the growth curves at drug concentrations which resulted in more than 50% growth (for itraconazole and terbinafine) and more than 75% growth (for amphotericin B) after 24 h of incubation for R. oryzae, 48 h for Aspergillus spp., and 72 h for S. prolificans were 4 h longer than the lag phases of the growth curves at the corresponding drug-free growth controls which varied from 4.4 h for R. oryzae, 6.5 h for A. flavus, 7.9 h for A. fumigatus, and 11.6 h for S. prolificans. The duration of the lag phases showed small experimental and interstrain variability, with differences of less than 2 h in most of the cases. Using this system, itraconazole and terbinafine resistance (presence of >50% growth) as well as amphotericin B resistance (presence of >75% growth) was determined within incubation periods of 5.0 to 7.7 h for R. oryzae (for amphotericin B resistance incubation for up to 12 h was required), 8.8 to 11.4 h for A. fumigatus, 6.7 to 8.5 h for A. flavus, and 13 to 15.6 h for S. prolificans while awaiting formal MIC determination by the NCCLS reference method.

Newer Systemic Antifungal Agents

The past few years have seen the advent of several new antifungal agents, including those of a new class and a new generation of an existing class. Caspofungin, the first available echinocandin, has greatly expanded the antifungal armamentarium by providing a cell wall-active agent with candidacidal activity as well as demonstrated clinical efficacy in the therapy of aspergillosis refractory to available therapy. In addition, in clinical trials, caspofungin had comparable efficacy to amphotericin B for candidaemia and invasive Candida infections. Caspofungin and two more recently introduced echinocandins, micafungin and anidulafungin, are available as intravenous formulations only and characterised by potent anti-candidal activity, as well as few adverse events and drug interactions. Voriconazole, the first available second-generation triazole, available in both intravenous and oral formulations, has added a new and improved therapeutic option for primary therapy of invasive aspergillosis and salvage therapy for yeasts and other moulds. In a randomised trial, voriconazole demonstrated superior efficacy and a survival benefit compared with amphotericin B followed by other licensed antifungal therapy. This and data from a noncomparative study led to voriconazole becoming a new standard of therapy for invasive aspergillosis. Voriconazole has several important safety issues, including visual adverse events, hepatic enzyme elevation and skin reactions, as well as a number of drug interactions. Posaconazole, only available orally and requiring dose administration four times daily, shows encouraging efficacy in difficult to treat infections due to zygomycetes. Ravuconazole, available in both intravenous and oral formulations, has broad-spectrum in vitro potency and in vivo efficacy against a wide range of fungal pathogens. Clinical studies are underway. Despite the advances offered with each of these drugs, the morbidity and mortality associated with invasive fungal infections remains unacceptable, especially for the most at-risk patients. For individuals with severe immunosuppression as a result of chemotherapy, graft-versus-host disease and its therapy, or transplantation, new drugs and strategies are greatly needed.

Invasive aspergillosis in patients with solid tumors

Invasive aspergillosis (IA) has been reported only rarely among patients with solid tumors. In the current study, the authors retrospectively identified 13 episodes of definite or probable IA (using European Organization for Research and Treatment of Cancer criteria) occurring in patients with solid tumors who were treated between 1994-2003. Nine patients had pulmonary IA and three patients were found to have IA of the brain. Seven patients (54%) had primary or metastatic brain tumors and 6 patients (46%) received systemic steroids within 30 days prior to the diagnosis of IA. The majority of patients (69%) had a lymphocyte count < 500/microL but only 1 patient was neutropenic within the 30 days before the diagnosis of IA was made. Nodular infiltrates and cavities were the most common radiologic findings. Seven patients (54%) responded to antifungal treatment.

Pulmonary Infiltrates in the Non-HIV-Infected Immunocompromised Patient

Pulmonary complications remain a major cause of both morbidity and mortality in immunocompromised patients. When such individuals present with radiographic infiltrates, the clinician faces a diagnostic challenge. The differential diagnosis in this setting is broad and includes both infectious and noninfectious processes. Rarely are the radiographic findings classic for one disease, and most potential etiologies have overlapping clinical and radiographic appearances. In recent years, several themes have emerged in the literature on this topic. First, an aggressive approach to identifying a specific etiology is necessary; as a corollary, diagnostic delay increases the risk for mortality. Second, the evaluation of these infiltrates nearly always entails bronchoscopy. Bronchoscopy allows identification of some etiologies with certainty, and often allows for the exclusion of infectious agents even if the procedure is otherwise unrevealing. Third, early use of CT scanning regularly demonstrates lesions missed by plain radiography. Despite these advances, initial therapeutic interventions include the use of broad-spectrum antibiotics and other anti-infectives in order to ensure that the patients is receiving appropriate therapy. With the results of invasive testing, these treatments are then narrowed. Frustratingly, outcomes for immunocompromised patients with infiltrates remain poor.

Rapid improvement of disseminated aspergillosis with caspofungin/voriconazole combination in an adult leukemic patient

A 57-year-old man with acute myeloid leukemia (AML) French-American-British (FAB) 4 developed disseminated invasive cerebral and pulmonary aspergillosis during postinduction aplasia. According to international consensus, infection was categorized as probable (two host factors: deep neutropenia for >10 days and refractory fever for >96 h; major clinical criteria of lower respiratory tract and CNS invasive fungal infection; positive results for galactomannan antigen in three blood samples). After the failure of standard amphotericin-based therapy, the spectacular regression of multifocal brain and lung lesions was rapidly achieved under a caspofungin acetate/voriconazole combination. Further permanent caspofungin maintenance with voriconazole added during aplasia periods permitted two consolidation courses and autograft-based intensification without any delay.

Polyene and cytokine treatment of experimental aspergillosis

The aim of the present study was to assess the efficacy of amphotericin B (AMB), AMB-intralipid admixture (AMB-IL) or nystatin-IL formulation (Ny-IL) in combination with granulocyte colony stimulating factor (G-CSF) in treatment of experimental murine aspergillosis. ICR mice were immunosuppressed by cyclophosphamide and 3 days later inoculated intravenously (i.v.) with Aspergillus fumigatus. Treatment was initiated 2 h later and administered for 5 consecutive days (polyenes, i.v.; G-CSF, intraperitoneally). Combination therapy, particularly G-CSF with AMB or AMB-IL, significantly increased the survival rate (up to 87.3%) and prolonged the mean survival time (MST) (up to 28.8 days) in comparison to untreated controls (0% survival, MST 6.7 days) and to treatment with polyenes alone (up to 51.5% survival, MST 18.4 days). These data indicate that combination therapy could be beneficial for management of disseminated aspergillosis in humans.