Antifungal combination therapy: where we stand.

Amphotericin B has been used in combination, simultaneously or sequentially, with fluconazole and itraconazole. However, there are no data from clinical trials to suggest the most appropriate use of these drug combinations. In vitro work has consistently described antagonism of polyenes and azoles, but new work suggests that hydrophilic azoles (e.g. fluconazole) with amphotericin B may not result in antagonistic effects, whereas lipophilic azoles (e.g. ketoconazole, itraconazole) antagonize the antifungal effects of amphotericin B. Experimental studies in animals with invasive candidiasis show that fluconazole and amphotericin B are not antagonistic and may be additive in their effects. In contrast, itraconazole and amphotericin B are antagonistic in this same murine candidiasis model. In animals infected with Aspergillus, itraconazole plus amphotericin B seem to be antagonistic when used simultaneously and possibly when used sequentially. Nevertheless, initial therapy with amphotericin B followed by itraconazole in patients with aspergillosis is a common clinical strategy. Recent data and concepts concerning the combined use of available antifungal drugs are discussed in this paper.     

Caspofungin: a review of its use in oesophageal candidiasis, invasive candidiasis and invasive aspergillosis

Echinocandins are a new class of antifungal agents with a novel mechanism of action (interference with fungal cell wall synthesis). Caspofungin (Cancidas), Caspofungin MSD) is the first echinocandin to be approved and is administered intravenously.Caspofungin 50 mg/day had similar efficacy to intravenous fluconazole 200 mg/day and was at least as effective as intravenous amphotericin B 0.5 mg/kg/day in patients with oesophageal candidiasis in two randomised, double-blind studies. A favourable combined clinical and endoscopic response occurred in 81% of caspofungin recipients versus 85% of fluconazole recipients and in 74% of caspofungin recipients versus 63% of amphotericin B recipients. A favourable combined response rate of approximate, equals 90% and approximate, equals 60% occurred in the stratum of patients with oesophageal candidiasis who received caspofungin or amphotericin B in a third randomised, double-blind study.Caspofungin (70 mg loading dose followed by 50 mg/day) had similar efficacy to intravenous amphotericin B (0.7-1.0 mg/kg/day in patients with neutropenia and 0.6-0.7 mg/kg/day in patients without neutropenia) in patients with invasive candidiasis in a double-blind, randomised trial. A favourable overall response occurred in 73.4% of caspofungin recipients and in 61.7% of amphotericin B recipients.In a noncomparative study, salvage therapy with caspofungin (70 mg loading dose followed by 50 mg/day) was effective in patients with invasive aspergillosis who were refractory to or did not tolerate standard antifungal therapy. A favourable response (complete plus partial response) occurred in 37 of 83 patients (45%).Caspofungin was generally well tolerated in clinical trials; it had similar tolerability to intravenous fluconazole and was better tolerated than intravenous amphotericin B. Significantly fewer caspofungin than amphotericin B recipients reported chills, fever, nausea or infusion-related adverse events. In conclusion, caspofungin is a valuable new antifungal agent with a novel mechanism of action. In comparative trials, caspofungin had similar efficacy to fluconazole and was at least as effective as amphotericin B in oesophageal candidiasis and had similar efficacy to amphotericin B in invasive candidiasis. In addition, caspofungin had similar tolerability to fluconazole and was better tolerated than amphotericin B in these indications. Caspofungin was also effective in patients with invasive aspergillosis who were refractory to or intolerant of standard antifungal agents. Thus, caspofungin provides an alternative to triazoles or amphotericin B in oesophageal candidiasis and an alternative to amphotericin B in invasive candidiasis, as well as being an effective salvage therapy in invasive aspergillosis.     

Antifungal agents in hematopoietic stem cell transplantation

Invasive fungal infections are major complications of stem cell transplantation associated with significant morbidity and mortality. Allogeneic stem cell transplant recipients are at a significantly greater risk for fungal infection than recipients of autologous transplantation. Although with the wide use of fluconazole prophylaxis the incidence and associated mortality of invasive candidiasis has been minimized, mold diseases remain a significant complication during periods of prolonged immunosuppression for graft versus host disease. Posaconazole prophylaxis during periods of high risk was recently demonstrated to be effective in preventing fungal infections and associated mortality. Preemptive strategy employing laboratory markers and serial CT scans to identify mold infection at an early stage is promising. However its efficacy has to be validated in clinical trials. Several new antifungal agents have been introduced lately, characterized by improved safety profile and broader antifungal spectrum. Voriconazole has become the standard of care for the treatment of invasive aspergillosis. Finally there has been increasing interest on combination therapy for invasive aspergillosis due to the high rate of failure of the currently available antifungals, especially in the profoundly immunocompromised host.     

Caspofungin: first approved agent in a new class of antifungals

Caspofungin (Cancidas, Merck & Co. Inc.) is the first echinocandin antifungal agent to gain FDA-approval for use in the US. It has excellent clinical activity against Candida spp. and Aspergillus spp. but lacks significant activity against Cryptococcus neoformans. Caspofungin may have some activity against dimorphic fungi such as Histoplasma capsulatum and Coccidioides immitis, but no clinical data is available for treatment of these infections. Caspofungin has demonstrated poor activity against most filamentous fungi in vitro. Several clinical trials have demonstrated its efficacy in the treatment of oropharyngeal, oesophageal and invasive candidiasis, as well as invasive aspergillosis. As a result of caspofungin's unique mechanism of action, and the high morbidity and mortality of invasive fungal infections, there is considerable interest in using this new antifungal agent as part of a combination antifungal therapy. In vitro studies and small case series indicate that caspofungin does not appear to be antagonistic when combined with other antifungals, such as itraconazole, voriconazole or amphotericin B against Aspergillus spp. Caspofungin exerts concentration-dependent killing effects in many different in vitro and animal models of disseminated fungal infection. The usual daily dose is 50 mg/day i.v. following a 70 mg i.v. loading dose. However, higher caspofungin doses have been safely administered and up to 70 mg/day can be administered for patients who fail to respond to lower doses. Caspofungin has an excellent safety profile with reduced toxicities, compared to other licensed antifungal agents. Fever, thrombophlebitis, headache and liver enzyme elevations were the most common drug-related side effects reported in clinical trials so far. Additional data are needed to document its safety in long-term use, and with higher doses in patients with invasive fungal infections. Caspofungin is a promising agent as first-line therapy for invasive candidiasis, and as salvage therapy for invasive aspergillosis. However, more clinical data are needed to define its role as primary therapy for invasive aspergillosis, and its role in combination antifungal therapy.     

Caspofungin: a review of its use in the treatment of fungal infections

Caspofungin (Cancidas) is the first of a new class of antifungal agents, the echinocandins, that inhibit the synthesis of the fungal cell wall component beta-(1,3)-D-glucan. Caspofungin is administered once daily by slow intravenous infusion and is used to treat infections caused by Candida spp. and Aspergillus spp.Caspofungin is a valuable new antifungal agent with a novel mechanism of action. In comparative clinical trials, caspofungin was no less effective than liposomal amphotericin B in the empirical treatment of neutropenic patients with persistent fever, amphotericin B deoxycholate in the treatment of invasive candidiasis or fluconazole in the treatment of oesophageal candidiasis. Caspofungin also displayed broadly similar efficacy to amphotericin B deoxycholate in oesophageal or oropharyngeal candidiasis and was effective as salvage therapy in patients with invasive aspergillosis who were refractory to or intolerant of standard therapy. The tolerability profile of caspofungin was similar to that of fluconazole and superior to that of amphotericin B deoxycholate and liposomal amphotericin B. Therefore, in the appropriate indications, caspofungin is a viable alternative to amphotericin B deoxycholate, liposomal amphotericin B or fluconazole.     

Posaconazole: a new broad-spectrum antifungal agent

The rising incidence of invasive fungal infections and the emergence of broader fungal resistance have led to the need for novel antifungal agents. Posaconazole is a new member of the triazole class of antifungals. It is available as an oral suspension and has a favorable toxicity profile, has demonstrated clinical efficacy in the treatment of oropharyngeal candidiasis and has shown promise as salvage therapy for invasive aspergillosis, zygomycosis, cryptococcal meningitis and a variety of other fungal infections. In addition, data from randomized controlled studies support its efficacy for use in prophylaxis of invasive fungal infections in patients who are severely immunocompromised. The wide spectrum activity of posaconazole in in vitro studies, animal models and preliminary clinical studies suggest that posaconazole represents an important addition to the antifungal armamentarium.     

Posaconazole: a new broad-spectrum antifungal agent

The rising incidence of invasive fungal infections and the emergence of broader fungal resistance have led to the need for novel antifungal agents. Posaconazole is a new member of the triazole class of antifungals. It is available as an oral suspension and has a favorable toxicity profile, has demonstrated clinical efficacy in the treatment of oropharyngeal candidiasis and has shown promise as salvage therapy for invasive aspergillosis, zygomycosis, cryptococcal meningitis and a variety of other fungal infections. In addition, data from randomized controlled studies support its efficacy for use in prophylaxis of invasive fungal infections in patients who are severely immunocompromised. The wide spectrum activity of posaconazole in in vitro studies, animal models and preliminary clinical studies suggest that posaconazole represents an important addition to the antifungal armamentarium.     

Fluconazole. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in superficial and systemic mycoses

Fluconazole is a bis-triazole antifungal drug with novel pharmacokinetic properties (metabolic stability, relatively high water solubility) which contribute to its therapeutic activity. Clinical experience is limited to a relatively small number of mycoses and, as might be expected at this early stage of development, optimal dosage and duration of treatment for some serious mycoses is not yet established. Further study to evaluate higher dosages and to establish the efficacy of fluconazole relative to more established antifungal agents is required. In patients with oropharyngeal or oesophageal candidiasis, fluconazole produces rapid relief and eradicates the yeast in 50 to 90% of patients. Relapse of oral infection is common in chronically immunocompromised patients regardless of the antifungal used, and adequate primary therapy plus long term prophylaxis appears necessary in patients with AIDS. A single oral dose of fluconazole was comparable to standard topical azole therapy in women with acute vaginal candidiasis. Preliminary reports of success against deep-seated candidiasis are encouraging; moreover, experience in noncomparative clinical trials suggests that fluconazole 200 to 400mg once daily resolves infection in the majority of seriously ill patients. Clinical improvement has been reported in a few cases of pulmonary Aspergillus infection but the overall efficacy of conventional dosages of fluconazole in this mycosis has not been as impressive. Early experience in coccidioidosis, predominantly meningitis, suggests a beneficial clinical effect with oral fluconazole in this difficult to treat mycosis but relapse remains a problem. Fluconazole is a promising treatment of cryptococcal meningitis. The rate of clinical resolution and eradication of Cryptococcus neoformans from cerebrospinal fluid has been similar between fluconazole and amphotericin B treatment groups in comparative trials. Comparative trials of maintenance therapy indicate a similar low rate of relapse among patients given oral fluconazole once daily and intravenous amphotericin B once weekly. However, these results are preliminary and further study is required. Fluconazole has been well tolerated to date but wider clinical experience is needed, especially with regard to the rate occurrence of hepatotoxicity and exfoliative skin reactions. The promising clinical response of patients with various forms of candidiasis or cryptococcosis--together with convenient administration regimens--recommends fluconazole as a useful addition to currently available systemic antifungal therapies, in particular for the treatment of mycoses in patients with AIDS.     

回顾性分析新型隐球菌性脑膜炎的诊断与治疗

目的 分析隐球菌性脑膜炎临床资料并探讨隐球菌性脑膜炎的诊断与治疗。方法 总结近8年来本院隐球菌性脑膜炎的诊断、治疗和预后情况。结果 23例患者中有6，3，2，2例分别误诊为结核性脑膜炎、病毒性脑膜炎、血管炎、系统性红斑狼疮脑病。比较氟康唑和两性霉素B联用与两性霉素B和氟胞嘧啶联用，其治疗痊愈率无明显差别。结论 隐球菌脑膜炎误诊率较高，建议对可疑病例做反复腰穿、墨汁涂片和霉菌培养。     

Caspofungin: pharmacology,safety and therapeutic potential in superficial and invasive fungal infections

Invasive fungal infections are important causes of morbidity and mortality in hospitalised patients. Current therapy with amphotericin B and antifungal triazoles has overlapping targets and is limited by toxicity and resistance. The echinocandin lipopeptide caspofungin is the first of a new class of antifungal compounds that inhibit the synthesis of 1,3-β-D-glucan. This homopolysaccharide is a major component of the cell wall of many pathogenic fungi and yet is absent in mammalian cells. It provides osmotic stability and is important for cell growth and cell division. In vitro, caspofungin has broad-spectrum antifungal activity against Candida and Aspergillus spp. without cross-resistance to existing agents. The compound exerts prolonged post-antifungal effects and fungicidal activity against Candida spp. and causes severe damage of Aspergillus fumigatus at the sites of hyphal growth. Animal models have demonstrated efficacy against disseminated candidiasis and disseminated and pulmonary aspergillosis, both in normal and in immunocompromised animals. Caspofungin possesses favourable pharmacokinetic properties and is not metabolised through the cytochrome P450 (CYP) enzyme system. It showed highly promising antifungal efficacy in Phase II and III clinical trials in immunocompromised patients with oesophageal candidiasis. Caspofungin was effective in patients with invasive aspergillosis intolerant or refractory to standard therapies. Based on its documented antifungal efficacy and an excellent safety profile, caspofungin has been approved recently by the US Food and Drug Administration for the treatment of invasive aspergillosis in patients who are refractory to or intolerant of other therapies (i.e., amphotericin B, lipid formulations of amphotericin B, and/or itraconazole). Phase III clinical trials in patients with candidaemia and in persistently febrile neutropenic patients requiring empirical antifungal therapy are ongoing. This paper reviews the preclinical and clinical pharmacology of caspofungin and its potential role for treatment of invasive and superficial fungal infections in patients.     

Caspofungin

Caspofungin is the first in a new class of antifungal agents, the glucan synthesis inhibitors, that interfere with fungal cell wall synthesis. Caspofungin exhibited in vitro and in vivo efficacy against a wide range of fungi and yeasts including Aspergillus and Candida species. A complete or partial response to caspofungin therapy was seen in 40.7% of immunocompromised adults with invasive aspergillosis who did not respond to, or did not tolerate, other antifungal agents in a noncomparative multicentre study. Caspofungin was effective in patients with oropharyngeal or oesophageal candidiasis, according to the preliminary results of 2 randomised double-blind trials. Caspofungin was generally well tolerated in a multicentre noncomparative trial involving patients with invasive aspergillosis. One or more drug-related clinical adverse effects were experienced by 13.8% of caspofungin recipients (the most common were fever, nausea, vomiting and complications associated with the vein into which caspofungin was infused). The tolerability of caspofungin appeared to be better than that of amphotericin B and similar to that of fluconazole in double-blind, randomised trials involving patients with mucosal candidiasis.     

Combination antifungal therapy for invasive aspergillosis: utilizing new targeting strategies

The optimal therapy for invasive aspergillosis (IA) is unknown, and there is little agreement on the exact antifungal management of IA. The previously stagnant landscape of antifungal choices for IA is rapidly changing with newer antifungals and newer targets. While amphotericin B has historically been the preferred therapy, recent studies support voriconazole as primary therapy or caspofungin as salvage therapy. However, even these newer therapies have only elevated clinical response rates to approximately 50%. Recent in vitro studies, animal models, and limited clinical reports suggest that combination antifungal therapy utilizing novel targeting strategies might offer improved outcome. Until very recently, combination antifungal therapy for IA was of little consequence since there were a limited number of possible permutations available. There has been a great deal of new data published exploring the possibilities of combination therapy, but clinicians need to be aware of the potential advantages and disadvantages of combination antifungal therapy for IA.     

Fungal infections in patients with neutropenia: challenges in prophylaxis and treatment

Fungal infections are a leading cause of mortality in patients with neutropenia. Candidiasis and aspergillosis account for most invasive fungal infections. General prophylactic measures include strict hygiene and environmental measures. Haemopoietic growth factors shorten the duration of neutropenia and thus may reduce the incidence of fungal infections. Fluconazole is appropriate for antifungal prophylaxis and should be offered to patients with prolonged neutropenia, such as high-risk patients with leukaemia undergoing remission induction or consolidation therapy and high-risk stem cell transplant recipients. Empirical antifungal therapy is mandatory in patients with persistent febrile neutropenia who fail to respond to broad-spectrum antibacterials. Intravenous amphotericin B at a daily dose of 0.6 to 1 mg/kg is preferred whenever aspergillosis cannot be ruled out. Lipid formulations of amphotericin B have demonstrated similar efficacy and are much better tolerated. Fluconazole is the best choice for acute candidiasis in stable patients; amphotericin B should be used in patients with unstable disease. Use of fluconazole is restricted by the existence of resistant strains (Candida krusei and, to a lesser extent, C. glabrata). Amphotericin B still remains the gold standard for invasive aspergillosis. Lipid formulations of amphotericin B are effective in aspergillosis and because they are less nephrotoxic are indicated in patients with poor renal function. Itraconazole is an alternative in patients who have good intestinal function and are able to eat. Mucormycosis, trichosporonosis, fusariosis and cryptococcosis are less common but require specific management. New antifungal agents, especially new azoles, are under development. Their broad in vitro spectrum and preliminary clinical results are promising.     

Newer systemic antifungal agents : pharmacokinetics, safety and efficacy

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.     

Echinocandins: A ray of hope in antifungal drug therapy

Invasive fungal infections are on the rise. Amphotericin B and azole antifungals have been the mainstay of antifungal therapy so far. The high incidence of infusion related toxicity and nephrotoxicity with amphotericin B and the emergence of fluconazole resistant strains of Candida glabrata egged on the search for alternatives. Echinocandins are a new class of antifungal drugs that act by inhibition of β (1, 3)-D- glucan synthase, a key enzyme necessary for integrity of the fungal cell wall.Caspofungin was the first drug in this class to be approved. It is indicated for esophageal candidiasis, candidemia, invasive candidiasis, empirical therapy in febrile neutropenia and invasive aspergillosis. Response rates are comparable to those of amphotericin B and fluconazole. Micafungin is presently approved for esophageal candidiasis, for prophylaxis of candida infections in patients undergoing hematopoietic stem cell transplant (HSCT) and in disseminated candidiasis and candidemia. The currently approved indications for anidulafungin are esophageal candidiasis, candidemia and invasive candidiasis.The incidence of infusion related adverse effects and nephrotoxicity is much lower than with amphotericin B. The main adverse effect is hepatotoxicity and derangement of serum transaminases. Liver function may need to be monitored. They are, however, safer in renal impairment. Even though a better pharmacoeconomical choice than amphotericin B, the higher cost of these drugs in comparison to azole antifungals is likely to limit their use to azole resistant cases of candidial infections and as salvage therapy in invasive aspergillosis rather than as first line drugs.     

symbol: see text]Caspofungin and [symbol: see text]voriconazole for fungal infections

Systemic fungal infections are difficult to treat and often fatal. Established treatment options include conventional amphotericin B or one of its lipid-based or liposomal formulations, or a triazole antifungal such as fluconazole or itraconazole. [symbol: see text]Caspofungin (Cancidas--Merck Sharp & Dohme) and [symbol: see text]voriconazole (Vfend--Pfizer) are two new antifungals for severe infections caused by Candida spp. (invasive candidiasis) and Aspergillus spp. (invasive aspergillosis). Caspofungin is the first licensed echinocandin antifungal, while voriconazole is a triazole. Promotional claims for caspofungin include that it "provides an effective, yet less toxic, alternative to amphotericin B" while voriconazole is claimed to offer "significantly improved survival in invasive aspergillosis compared with amphotericin B". Here we consider the place of caspofungin and voriconazole in managing patients with severe fungal infections.     

Immunotherapy for invasive fungal infections: from bench to bedside.

Immunotherapy for invasive fungal infections has been an area of significant research and clinical interest since the first-half of the twentieth century when hyperimmune equine immunoglobulin was first successfully administered to patients with acute and chronic cryptococcal meningitis. Since that time, effective antifungal compounds have been developed, but a much more complex array of host disorders have also emerged creating an even greater need for immunotherapy in conjunction with conventional antifungal therapy. In this review, the scientific foundation supporting the use of various immunotherapeutic interventions including granulocyte infusions, cytokine growth factors, pro-inflammatory cytokines including IFN-gamma and interleukin-12, immunoglobulin therapy, and active immunization will be discussed. Clinical data supporting the use of these interventions are often scant and inconclusive, however, relevant clinical information will be presented. In theory, adjunctive immunotherapy for invasive fungal infections has significant potential for improving clinical outcomes in a growing population of patients at risk for these potentially devastating infections. Clearly, randomized double-blind clinical trials will need to be performed to better understand the precise role of these interventions. There are several obstacles preventing the conduct of these studies, but these pressing clinical issues must be addressed through carefully considered study design and effective implementation.     

Treatment of acute cryptococcal disease

Successful treatment outcome for cryptococcal disease has been available since the introduction of the polyene antifungal, amphotericin B. Over the past 15 - 20 years, treatment of acute cryptococcal disease has dramatically improved. Several therapeutic strategies have been introduced which improve overall outcome of therapy and help decrease the duration of treatment. Not surprisingly, most data now exists on the treatment of AIDS-associated cryptococcal disease, especially cryptococcal meningitis. Currently, amphotericin B with or without flucytosine is regarded as the best initial therapy for patients with meningitis or more severe illness, although, the azoles and other formulations of amphotericin B can considered in other situations. The choice of treatment for cryptococcal disease depends on both the anatomic sites of involvement and the host’s immune status, all of which will be addressed in this article.     

Treatment of acute cryptococcal disease

Successful treatment outcome for cryptococcal disease has been available since the introduction of the polyene antifungal, amphotericin B. Over the past 15-20 years, treatment of acute cryptococcal disease has dramatically improved. Several therapeutic strategies have been introduced which improve overall outcome of therapy and help decrease the duration of treatment. Not surprisingly, most data now exists on the treatment of AIDS-associated cryptococcal disease, especially cryptococcal meningitis. Currently, amphotericin B with or without flucytosine is regarded as the best initial therapy for patients with meningitis or more severe illness, although, the azoles and other formulations of amphotericin B can considered in other situations. The choice of treatment for cryptococcal disease depends on both the anatomic sites of involvement and the host's immune status, all of which will be addressed in this article.     

Systemic antifungal therapy: new options, new challenges

The frequency of invasive fungal infections has increased dramatically in recent decades because of an expanding population at risk. Until now, treatment options for invasive mycoses have been primarily amphotericin B and the azoles, fluconazole and itraconazole. Traditional agents are limited by an inadequate spectrum of activity, drug resistance, toxicities, and drug-drug interactions. The recent approval of caspofungin and voriconazole clearly has expanded the number of existing antifungal drugs available. However, the enthusiasm that accompanies their availability is counterbalanced by limited clinical experience, high drug acquisition costs, and distinctive toxicities. The pharmacologic characteristics, extent of clinical experience (efficacy and toxicity), and drug acquisition costs among available systemic antifungal agents are compared, with emphasis on the new agents. Also, recommendations on the role of each agent are provided according to the most common indications for systemic antifungal therapy: invasive candidiasis, invasive aspergillosis, and febrile neutropenia.