Need for alternative trial designs and evaluation strategies for therapeutic studies of invasive mycoses

Preclinical Pharmacokinetic/Pharmacodynamic Studies and Clinical Trials in the Drug Development Process of EMA-Approved Antifungal Agents: A Review

Antifungal drug development is essential as invasive fungal disease is still associated with a very high mortality rate and the emergence of resistant species in the last decade. In Europe, the European Medical Agency (EMA) approves antifungals and publishes the European Public Assessment Report (EPAR) including the information leading up to the authorisation. We looked at EMA-approved antifungals and their reports within the last 23 years. We focused primarily on the role of pharmacokinetic/pharmacodynamic indices in antifungal development and the level of information depicted in their corresponding report. Furthermore, we investigated guidelines applicable to the development process at the time and compared the content with a focus on pharmacokinetic/pharmacodynamic studies and preclinical requirements. Since 2000, six new antifungal substances have been authorised. Most were authorised for treatment of Candida infections or Aspergillus infections but also included rarer pathogens. Pharmacokinetic/pharmacodynamic indices were scarcely investigated and/or mentioned in the report. Current antifungal EMA guidelines started emphasising investigating pharmacokinetic/pharmacodynamic indices in 2010 and then again in 2016. It remains to be seen how this translates into the authorisation process for new antifungals.

Recent drug development and treatments for fungal infections

Fungal infections are now becoming a hazard to individuals which has paved the way for research to expand the therapeutic options available. Recent advances in drug design and compound screening have also increased the pace of the development of antifungal drugs. Although several novel potential molecules are reported, those discoveries have yet to be translated from bench to bedside. Polyenes, azoles, echinocandins, and flucytosine are among the few antifungal agents that are available for the treatment of fungal infections, but such conventional therapies show certain limitations like toxicity, drug interactions, and the development of resistance which limits the utility of existing antifungals, contributing to significant mortality and morbidity. This review article focuses on the existing therapies, the challenges associated with them, and the development of new therapies, including the ongoing and recent clinical trials, for the treatment of fungal infections. Advancements in antifungal treatment: a graphical overview of drug development, adverse effects, and future prospects.

Application of anti-fungal vaccines as a tool against emerging anti-fungal resistance

After viruses and bacteria, fungal infections remain a serious threat to the survival and well-being of society. The continuous emergence of resistance against commonly used anti-fungal drugs is a serious concern. The eukaryotic nature of fungal cells makes the identification of novel anti-fungal agents slow and difficult. Increasing global temperature and a humid environment conducive to fungal growth may lead to a fungal endemic or a pandemic. The continuous increase in the population of immunocompromised individuals and falling immunity forced pharmaceutical companies to look for alternative strategies for better managing the global fungal burden. Prevention of infectious diseases by vaccines can be the right choice. Recent success and safe application of mRNA-based vaccines can play a crucial role in our quest to overcome anti-fungal resistance. Expressing fungal cell surface proteins in human subjects using mRNA technology may be sufficient to raise immune response to protect against future fungal infection. The success of mRNA-based anti-fungal vaccines will heavily depend on the identification of fungal surface proteins which are highly immunogenic and have no or least side effects in human subjects. The present review discusses why it is essential to look for anti-fungal vaccines and how vaccines, in general, and mRNA-based vaccines, in particular, can be the right choice in tackling the problem of rising anti-fungal resistance.

Novel Insights into Fungal Infections Prophylaxis and Treatment in Pediatric Patients with Cancer

Invasive fungal diseases (IFDs) are a relevant cause of morbidity and mortality in children with cancer. Their correct prevention and management impact patients’ outcomes. The aim of this review is to highlight the rationale and novel insights into antifungal prophylaxis and treatment in pediatric patients with oncological and hematological diseases. The literature analysis showed that IFDs represent a minority of cases in comparison to bacterial and viral infections, but their impact might be far more serious, especially when prolonged antifungal therapy or invasive surgical treatments are required to eradicate colonization. A personalized approach is recommended since pediatric patients with cancer often present with different complications and require tailored therapy. Moreover, while the Aspergillus infection rate does not seem to increase, in the near future, new therapeutic recommendations should be required in light of new epidemiological data on Candidemia due to resistant species. Finally, further studies on CAR-T treatment and other immunotherapies are needed in patients with unique needs and the risk of complications. Definitive guidelines on IFD treatment considering the evolving epidemiology of antifungal resistance, new therapeutic approaches in pediatric cancer, novel antifungal drugs and the importance of an appropriate antifungal stewardship are urgently needed.

Methodological and reporting quality of non-inferiority randomized controlled trials comparing antifungal therapies: a systematic review

BACKGROUND

Detailed reporting is essential in non-inferiority randomized controlled trials (NI-RCTs) to assess evidence quality, as these trials inform standards of care.

OBJECTIVES

The primary objective was to evaluate the methodological and reporting quality of antifungal NI-RCTs.

DATA SOURCES

Medline, EMBASE, the Cochrane CENTRAL and the United States Federal Drug Administration (FDA) drugs database were searched to 9 September 2020.

STUDY ELIGIBILITY CRITERIA

NI-RCTs differing by antifungal formulation, type, dose, administration and/or duration were included. Articles were independently assessed in duplicate using quality indicators developed by the Consolidated Standards of Reporting Trials (CONSORT) group.

PARTICIPANTS

Patients enrolled in antifungal trials for prophylactic and therapeutic use.

METHODS

The Cochrane RoB 2.0 tool was used to assess risk of bias. Descriptive statistics were used; all statistical tests were two sided.

RESULTS

Of 32 included studies, 22 (68.7%) did not justify the NIM. Handling of missing data was not described in 20 (62.5%). Intention-to-treat (ITT) and per-protocol (PP) analyses were both reported in 12/32 (37.5%) studies. Eleven of 32 studies (34.3%) reported potentially misleading conclusions. Industry-financed studies were more likely to report only the ITT analysis (n = 14/27, 51.9%). Methodological and reporting quality was unaffected by publication year; risk of bias from missing data changed over time. Overall risk of bias across included studies was moderate to high, with high risk in randomization process (n = 8/32, 25%), missing outcome data (n = 5/32, 15.6%), and selection of reported result (n = 9/32, 28.1%).

CONCLUSIONS

Justification of the non-inferiority margin, reporting of ITT and PP analyses, missing data handling description, and ensuring conclusions are consistent with reported data is necessary to improve CONSORT adherence. Small sample size and overall risk of bias are study limitations. (Systematic Review Registration Number PROSPERO CRD42020219497).

Antimicrobial Peptides: a New Frontier in Antifungal Therapy

Invasive fungal infections in humans are generally associated with high mortality, making the choice of antifungal drug crucial for the outcome of the patient. The limited spectrum of antifungals available and the development of drug resistance represent the main concerns for the current antifungal treatments, requiring alternative strategies. Antimicrobial peptides (AMPs), expressed in several organisms and used as first-line defenses against microbial infections, have emerged as potential candidates for developing new antifungal therapies, characterized by negligible host toxicity and low resistance rates. Most of the current literature focuses on peptides with antibacterial activity, but there are fewer studies of their antifungal properties. This review focuses on AMPs with antifungal effects, including their in vitro and in vivo activities, with the biological repercussions on the fungal cells, when known. The classification of the peptides is based on their mode of action: although the majority of AMPs exert their activity through the interaction with membranes, other mechanisms have been identified, including cell wall inhibition and nucleic acid binding. In addition, antifungal compounds with unknown modes of action are also described. The elucidation of such mechanisms can be useful to identify novel drug targets and, possibly, to serve as the templates for the synthesis of new antimicrobial compounds with increased activity and reduced host toxicity.

Combination Antifungal Therapy: A Review of Current Data

The incidence of invasive fungal infections has been on the rise, particularly in transplant recipients and in patients with hematological malignancies and other forms of immunosuppression. There is a mismatch between the rate of antifungal resistance and the development of new antifungal agents. Based on this, the idea of combining antifungals in the treatment of invasive fungal infections appears tempting for many clinicians, particularly after many in vitro studies showed synergism between many antifungal agents. Several randomized controlled trials have been published regarding the efficacy and safety of combination of antifungals, but the high cost, the limited number of cases and the multitude of confounding factors lead in some instances to weak and sometimes contradictory results. The lack of consensus in many clinical scenarios raises the importance of the need for more studies about combination antifungal therapies and should incite infectious disease societies to develop specific recommendations for the clinicians to follow while approaching patients with invasive fungal infections.

Systemic Antifungal Agents: Current Status and Projected Future Developments

By definition, an antifungal agent is a drug that selectively destroys fungal pathogens with minimal side effects to the host. Despite an increase in the prevalence of fungal infections particularly in immunocompromised patients, only a few classes of antifungal drugs are available for therapy, and they exhibit limited efficacy in the treatment of life-threatening infections. These drugs include polyenes, azoles, echinocandins, and nucleoside analogs. This chapter focuses on the currently available classes and representatives of systemic antifungal drugs in clinical use. We further discuss the unmet clinical needs in the antifungal research field; efforts in reformulation of available drugs such as Amphotericin B nanoparticles for oral drug delivery; development of new agents of known antifungal drug classes, such as albaconazole, SCY-078, and biafungin; and new drugs with novel targets for treatment of invasive fungal infections, including nikkomycin Z, sordarin derivatives, VT-1161 and VT-1129, F901318, VL-2397, and T-2307.

The role of the de novo pyrimidine biosynthetic pathway in Cryptococcus neoformans high temperature growth and virulence

Fungal infections are often difficult to treat due to the inherent similarities between fungal and animal cells and the resulting host toxicity from many antifungal compounds. Cryptococcus neoformans is an opportunistic fungal pathogen of humans that causes life-threatening disease, primarily in immunocompromised patients. Since antifungal therapy for this microorganism is limited, many investigators have explored novel drug targets aim at virulence factors, such as the ability to grow at mammalian physiological temperature (37°C). To address this issue, we used the Agrobacterium tumefaciens gene delivery system to create a random insertion mutagenesis library that was screened for altered growth at elevated temperatures. Among several mutants unable to grow at 37°C, we explored one bearing an interruption in the URA4 gene. This gene encodes dihydroorotase (DHOase) that is involved in the de novo synthesis of pyrimidine ribonucleotides. Loss of the C. neoformans Ura4 protein, by targeted gene interruption, resulted in an expected uracil/uridine auxotrophy and an unexpected high temperature growth defect. In addition, the ura4 mutant displayed phenotypic defects in other prominent virulence factors (melanin, capsule and phospholipase) and reduced stress response compared to wild type and reconstituted strains. Accordingly, this mutant had a decreased survival rate in macrophages and attenuated virulence in a murine model of cryptococcal infection. Quantitative PCR analysis suggests that this biosynthetic pathway is induced during the transition from 30°C to 37°C, and that transcriptional regulation of de novo and salvage pyrimidine pathway are under the control of the Ura4 protein.

Antifungal drug development: challenges, unmet clinical needs, and new approaches

Invasive, life-threatening fungal infections are an important cause of morbidity and mortality, particularly for patients with compromised immune function. The number of therapeutic options for the treatment of invasive fungal infections is quite limited when compared with those available to treat bacterial infections. Indeed, only three classes of molecules are currently used in clinical practice and only one new class of antifungal drugs has been developed in the last 30 years. Here we summarize the unmet clinical needs of current antifungal therapy, discuss challenges inherent to antifungal drug discovery and development, and review recent developments aimed at addressing some of these challenges.

Utilization and comparative effectiveness of caspofungin and voriconazole early after market approval in the U.S

Objectives

Both caspofungin and voriconazole were initially approved by the FDA with very narrow indications. Our aim was to evaluate the utilization patterns and comparative effectiveness of these agents early after marketing before any labeling change occurred.

Methods

This was a retrospective cohort study utilizing a large healthcare database in the United States. Patients who received at least one dose of systemic antifungal agent between the years 2001 and 2003 were included. Information was available for each hospital-day including underlying conditions, medications, procedures and disease severity scores. Tests for proportions, trend tests and logistic regression were used for evaluation of utilization. Propensity score analysis was used in comparison of mortality.

Results

The study cohort included 381,245 patients with serious underlying conditions. In just two years after marketing, caspofungin and voriconazole use increased to 40% of the total systemic antifungal consumption. However, only 3.4% of caspofungin and 12.5% of voriconazole were used as indicated in labeling. In the propensity score analyses, caspofungin was associated with 7% decrease in mortality (OR: 0.93 95% CI: 0.85–0.98). Voriconazole use was not found to be associated with mortality (OR: 1 . 95% CI: 0.89–1.12)

Conclusions

Caspofungin and voriconazole were mostly used of unapproved indications immediately after their marketing. Although unapproved drug use might be due to a crucial need by clinicians, this may create problems in further antifungal drug development. Our results suggest a survival benefit with caspofungin; however, similar comparative effectiveness studies must be repeated using more recent data.

Response to azolic antifungal agents for treating feline sporotrichosis

The effectiveness and safety of treatment with ketoconazole and itraconazole were compared in 773 sporotrichosis-infected cats over a four-year period (2002 to 2005). Five hundred and ninety-eight cats received oral ketoconazole and 175 received oral itraconazole. Treatment was successful in 238 (30.8 per cent) cats, of which 171 (28.6 per cent) of 598 received 13.5 to 27.0 mg/kg/day ketoconazole and 67 (38.3 per cent) of 175 received 8.3 to 27.7 mg/kg/day itraconazole. Adverse effects were reported in 306 (39.6 per cent) of the cats, 105 (13.6 per cent) died and 430 (55.6 per cent) dropped out of treatment or were still under treatment at the time of data analysis.

Changes in the proteome of Candida albicans in response to azole, polyene, and echinocandin antifungal agents

The yeast Candida albicans is an opportunistic human fungal pathogen and the cause of superficial and systemic infections in immunocompromised patients. The classes of antifungal agents most commonly used to treat Candida infections are the azoles, polyenes, and echinocandins. In the present study, we identified changes in C. albicans protein abundance using two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption ionization-time of flight mass spectroscopy following exposure to representatives of the azole (ketoconazole), polyene (amphotericin B), and echinocandin (caspofungin) antifungals in an effort to elucidate the adaptive responses to these classes of antifungal agents. We identified 39 proteins whose abundance changed in response to ketoconazole exposure. Some of these proteins are involved in ergosterol biosynthesis and are associated with azole resistance. Exposure to amphotericin B altered the abundance of 43 proteins, including those associated with oxidative stress and osmotic tolerance. We identified 50 proteins whose abundance changed after exposure to caspofungin, including enzymes involved in cell wall biosynthesis and integrity, as well as the regulator of beta-1,3-glucan synthase activity, Rho1p. Exposure to caspofungin also increased the abundance of the proteins involved in oxidative and osmotic stress. The common adaptive responses shared by all three antifungal agents included proteins involved in carbohydrate metabolism. Some of these antifungal-responsive proteins may represent potential targets for the development of novel therapeutics that could enhance the antifungal activities of these drugs.

Recent advances in antifungal prevention and treatment

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

Should we continue using amphotericin B deoxycholate for the treatment of fungal infections? Adverse events and clinical outcomes

Amphotericin B deoxycholate (AmBd) has been a standard therapy for IFI but is associated with high adverse event and mortality rates. A retrospective review was undertaken to describe adverse events and clinical outcomes in adult patients with IFI treated with only AmBd as initial therapy.

Pharmacoeconomics of antifungal pharmacotherapy – challenges and future directions

The frequency and severity of invasive fungal infections have been increasingly recognised and new antifungal therapies have expanded the therapeutic armamentarium available to manage such infections. Antifungal agents comprise a significant portion of antibiotic expenditures at major medical centres, prompting adoption of cost-containment measures and treatment guidelines. This paper reviews available data regarding the costs associated with managing fungal infections, including pharmacoeconomic analyses that have been performed in the setting of documented fungal infections, as well as prophylactic and empiric use of antifungal agents. The challenges of performing such studies are discussed, as well as the limitations of published investigations. Finally, recommendations are made regarding the design and implementation of future pharmacoeconomic analyses that can help establish the true costs of managing invasive fungal infections in at-risk patient populations.

Combination therapy for invasive mycoses: evaluation of past clinical trial designs

BACKGROUND

Despite the availability of new antifungals, single-agent therapy frequently falls short of high cure rates. Combination therapy offers potentially higher cure rates, especially for resistant organisms. In vitro studies and experimental animal models have provided conflicting data.

METHODS

Retrospective, randomized, controlled clinical studies were reviewed.

RESULTS

Results indicate a clear advantage for polyene and flucytosine combination therapy in cryptococcal meningitis and a possible advantage for combination amphotericin B and fluconazole for candidemia. Unfortunately, the few studies published have been flawed by design problems that have compromised the determination of outcome. Study review allows investigators the opportunity to design future studies to ensure optimal evaluation of efficacy.

CONCLUSION

Combination antifungal therapy is advantageous in cryptococcal diseases and may have a role in the treatment of invasive candidiasis. The greatest potential exists for combination therapy against aspergillosis and resistant fungi in patients with refractory mycotic disease who experience failure of monotherapy.

Assessment of preemptive treatment to prevent severe candidiasis in critically ill surgical patients(*)

OBJECTIVE

To assess the efficacy of a preemptive antifungal therapy in preventing proven candidiasis in critically ill surgical patients.

DESIGN

Before/after intervention study, with 2-yr prospective and 2-yr historical control cohorts.

SETTING

Surgical intensive care unit (SICU) in a university-affiliated hospital.

PATIENTS

Nine hundred and thirty-three patients, 478 in the prospective group and 455 in the control group, with SICU stay > or =5 days.

INTERVENTIONS

During the prospective period, systematic mycological screening was performed on all patients admitted to the SICU, immediately at admittance and then weekly until discharge. A corrected colonization index was used to assess intensity of Candida mucosal colonization. Patients with corrected colonization index > or =0.4 received early preemptive antifungal therapy (fluconazole intravenously: loading dose 800 mg, then 400 mg/day for 2 wks).

MEASUREMENTS AND MAIN RESULTS

End points of this study were the frequency of proven candidiasis, especially SICU-acquired candidiasis. During the retrospective period, 32 patients of 455 (7%) presented with proven candidiasis: 22 (4.8%) were imported and 10 (2.2%) were SICU-acquired cases. During the prospective period, 96 patients with corrected colonization index > or =0.4 of 478 received preemptive antifungal treatment and only 18 cases (3.8%) of proven candidiasis were diagnosed; all were imported infections. Candida infections occurred more frequently in the control cohort (7% vs. 3.8%; p = .03). Incidence of SICU-acquired proven candidiasis significantly decreased from 2.2% to 0% (p < .001, Fisher test). Incidence of proven imported candidiasis remained unchanged (4.8% vs. 3.8%; p = .42). No emergence of azole-resistant Candida species (especially Candida glabrata, Candida krusei) was noted during the prospective period.

CONCLUSIONS

Targeted preemptive strategy may efficiently prevent acquisition of proven candidiasis in SICU patients. Further studies are being performed to assess cost-effectiveness of this strategy and its impact on selection of azole-resistant Candida strains on a long-term basis.

Design of Efficacy Trials of Cytokines in Combination with Antifungal Drugs

Resolution of invasive fungal infections is often dependent on recovery from an immunocompromised state, which indicates that host defense mechanisms are extremely important in the clearance of fungal pathogens. Immunotherapy aimed at enhancement of host defense mechanisms may improve clinical outcome of invasive mycoses. The design of trials of immunotherapy against fungal pathogens requires profound knowledge of the host defense mechanisms that are involved in invasive fungal infections. Prospective phase II studies with recombinant granulocyte colony-stimulating factor and interferon-gamma have been done. Recombinant interferon-gamma is a candidate for phase III trials of adjunctive immunotherapy for cryptococcal meningitis, invasive aspergillosis, and candidemia, but the proper design of future trials will be crucial to establish whether immunotherapy is of clinical value in the treatment of invasive fungal infections.

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.

New and emerging antifungal agents: impact on respiratory infections

Fungal pathogens are increasingly important causes of respiratory disease, yet the number of antifungal agents available for clinical use is limited. Use of amphotericin B deoxycholate is hampered by severe toxicity. Triazole agents currently available have significant drug interactions; fluconazole has a limited spectrum of activity and itraconazole was, until recently, available only in oral formulations with limited bioavailability. The development of resistance to all three agents is increasingly being recognized and some filamentous fungi are resistant to the action of all of these agents. In the past few years, new antifungal agents and new formulations of existing agents have become available.The use of liposomal amphotericin B preparations is associated with reduced, but still substantial, rates of nephrotoxicity and infusion-related reactions. An intravenous formulation of itraconazole has been introduced, and several new triazole agents have been developed, with the view of identifying agents that have enhanced potency, broader spectra of action and improved pharmacodynamic properties. One of these, voriconazole, has completed large-scale clinical trials. In addition, caspofungin, the first of a new class of agents, the echinocandins, which inhibit cell wall glucan synthesis, was approved for use in the US in 2001 as salvage therapy for invasive aspergillosis. It is hoped that the availability of these agents will have a significant impact on the morbidity and mortality of fungal respiratory infections. However, at the present time, our ability to assess their impact is limited by the problematic nature of conducting trials for antifungal therapy.

Combination chemotherapy for invasive fungal infections: what laboratory and clinical studies tell us so far

Despite potential benefits, few objective clinical data (with the exception of cryptococcocal meningitis) are available supporting the routine use of combination antifungal regimens in patients with invasive mycoses, importantly aspergillosis or candidiasis. There is considerable debate on what constitutes synergy or antagonism in vitro and whether these laboratory findings are translated to beneficial interactions in patients. Given the lack of rigorous clinical data, a better understanding of the important concepts for the justification of the clinical and pharmacoeconomic threshold of antifungal therapy is needed. Such concepts include standardized methods for screening antifungal combinations in culture or in animals and collaborative efforts to collect clinical data on the efficacy and safety of combination regimens.

Amphotericin B: time for a new "gold standard"

When introduced in 1959, amphotericin B deoxycholate (AmBD) was clearly a life-saving drug. Randomized studies demonstrating its efficacy were not thought to be necessary, and it was granted indications for many invasive fungal infections. Despite its formidable toxicities, AmBD is thus often used as the primary comparator in studies of invasive fungal infections. Safer lipid-based versions of amphotericin B (AmB) have been introduced, but difficulties with studying these agents generally led to licensure for salvage therapy, not primary therapy. However, the cumulative clinical experience to date with the lipid-based preparations is now adequate to demonstrate that these agents are no less active than AmBD, and, for some infections, it can now be stated that specific lipid-based preparations of AmB are superior to AmBD. Given their superior safety profiles, these preparations can now be considered suitable replacements for AmBD for primary therapy for many invasive fungal infections in clinical practice and research.

Fungal pneumonias in transplant recipients

Fungi are ubiquitous in the environment. Opportunistic fungal pneumonias in the immunocompromised host continue to increase most commonly due to Aspergillus sp. Affected patients are usually hematopoietic stem cell and lung transplant recipients. Clinical presentation is protean, and the diagnosis is challenging. Culture of respiratory specimens has limited utility. The detection of circulating fungal antigens and DNA seems promising, but more studies are needed. Value of prophylactic strategies or preemptive therapy remains contentious. New antifungal drugs for managing invasive pulmonary aspergillosis continue to emerge, with better safety, efficacy, and pharmacologic profiles.

Forum report: issues in the evaluation of diagnostic tests, use of historical controls, and merits of the current multicenter collaborative groups

This forum report contains conclusions about 3 different issues relevant to conducting clinical trials in deep mycoses. (1) Trials of diagnostic tests for deep mycoses must define the population appropriate for testing and the clinical question being asked. The unanswered question for the serum Aspergillus galactomannan assay is whether knowledge of results can change use of empirical therapy to treat febrile patients at high risk of invasive aspergillosis. (2) Use of historical controls is suboptimal but offers a pragmatic solution for studying rare mycoses; use of contemporaneous controls, matched for critical variables and evaluated by a blinded data review committee using detailed criteria, appears optimal. (3) Established groups of independent investigators, such as the European Organization for Research on Treatment of Cancer's Invasive Fungal Infections Group and National Institute of Allergy and Infectious Diseases's Bacteriology and Mycology Study Group, provide a pool of experienced investigators, defined operating rules, impartiality, and specialized expertise. Considering the enormous investment required for adequately powered efficacy trials of antifungal agents and the importance of these trials to guide clinical practice, use of collaborative groups outweighs the extra administrative time that is sometimes required.

Antifúngicos de uso sistémico

Invasive fungal infection is the infectious complication with highest associated mortality. Until the 90's amphotericin B was the only drug available to treat these infections. Its spectrum of antifungal activity is excellent, but its use is associated with toxicity in many cases. The development of amphotericin B lipid formulations has resulted in a significant decrease in most of the side effects associated with this drug. Triazoles are safe and effective for treating most invasive fungal infections. Fluconazole is an excellent drug for the prevention and treatment of Candida and Cryptococcus infections, itraconazole has good activity against Candida and Aspergillus, and voriconazole has shown to be better than amphotericin B for invasive aspergillosis. Caspofungin belongs to a new group of antifungal agents, the echinocandins, which are very safe and present excellent activity against Candida and Aspergillus.

Invasive fungal infections: evolving challenges for diagnosis and therapeutics

Invasive fungal infections (IFI) parallel the explosive increase in the immunocompromized patient population, and are characterized by diagnostic difficulties and extreme mortality. Candidemia in a tertiary referral hospital in the Middle East confirms the current epidemiologic shift in this common blood stream pathogen towards non-malignancy cases (38%) and antifungal prophylaxis failure (20%), high presentation sepsis scores and attributable mortality (32%). Invasive aspergillosis (IA) is also associated with high mortality. Use of non-invasive computerized tomographic (CT) radiologic scanning linked to early administration of high dose liposomal amphotericin B (LAB) is associated with a reduced mortality of 9.5% compared to historical experience of 28%.Life threatening invasive aspergillosis also occurs in patients who are less obviously immunocompromized. Investigations may reveal subtle immune deficits which could place the patient at some risk for an invasive mycosis. Antifungal treatment used in combination with progenitor cell growth factors and gamma-interferon has proved successful in such situations of progressive fungal disease unresponsive to antifungal therapy alone. Pharmacologic remodeling of existing compounds by lipidisation reduces both the toxicity denominator and the efficacy numerator of the therapeutic index when compared to the parent drug. A comparative dose study of liposomal amphotericin B in aspergillosis has demonstrated equi-efficacy, generated debate over the ability of the controlled clinical trial to be capable of assessing antifungal efficacy, and illustrated that recovery from an invasive fungal infection may require maximum tolerated doses and immunomanipulation. Several new antifungal strategies are under clinical investigation. These include reformulating existing antifungals, exploitation of the growing knowledge of virulence factors to synthesize antagonists, immune reconstitution and immunoprotection. An interim analysis of an ongoing placebo controlled study of recombinant interleukin-11 to assess its efficacy in reducing sepsis in leukemia patients through prevention of chemotherapy induced gut epithelial cell apoptosis, has demonstrated a difference in the two study arms in sepsis rates and preservation of gastrointestinal epithelial cell integrity. The unique and special challenges presented by the dynamic epidemiologics of invasive fungal infections are demanding and attracting considerable responses, in the fields of diagnosis and therapeutics. Current strategies need considerable improvement, yet ongoing collaborative efforts will have a positive impact on our understanding of the fungus-host interaction and ultimately our ability to offer better care for our patients with invasive mycoses.

Invasive pulmonary aspergillosis

Invasive pulmonary aspergillosis is the most common fungal pulmonary infection in certain immunocompromised patients. The most commonly affected patients are hematopoietic stem cell transplant recipients and patients with hematological malignancies undergoing intensive chemotherapy. The survival of patients with invasive pulmonary aspergillosis is very poor because of difficulties in early diagnosis and lack of effective treatment options. Research efforts are being made constantly to improve different diagnostic techniques. Early, repeated, high resolution computed tomography of the chest, and sequential nonculture-based monitoring of Aspergillus antigen and DNA can improve earlier diagnosis. New antifungal drugs for treatment and prevention of invasive pulmonary aspergillosis continue to emerge, with better safety, efficacy, and pharmacologic profiles.

Preventing opportunistic infections after hematopoietic stem cell transplantation: the Centers for Disease Control and Prevention, Infectious Diseases Society of America, and American Society for Blood and Marrow Transplantation Practice Guidelines and beyond

This review presents evidence-based guidelines for the prevention of infection after blood and marrow transplantation. Recommendations apply to all myeloablative transplants regardless of recipient (adult or child), type (allogeneic or autologous) or source (peripheral blood, marrow or cord blood) of transplant. In Section I, Dr. Dykewicz describes the methods used to rate the strength and quality of published evidence supporting these recommendations and details the two dozen scholarly societies and federal agencies involved in the genesis and review of the guidelines. In Section II, Dr. Longworth presents recommendations for hospital infection control. Hand hygiene, room ventilation, health care worker and visitor policies are detailed along with guidelines for control of specific nosocomial and community-acquired pathogens. In Section III, Dr. Boeckh details effective practices to prevent viral diseases. Leukocyte-depleted blood is recommended for cytomegalovirus (CMV) seronegative allografts, while ganciclovir given as prophylaxis or preemptive therapy based on pp65 antigenemia or DNA assays is advised for individuals at risk for CMV. Guidelines for preventing varicella-zoster virus (VZV), herpes simplex virus (HSV) and community respiratory virus infections are also presented. In Section IV, Drs. Baden and Rubin review means to prevent invasive fungal infections. Hospital design and policy can reduce exposure to air contaminated with fungal spores and fluconazole prophylaxis at 400 mg/day reduces invasive yeast infection. In Section V, Dr. Sepkowitz details effective clinical practices to reduce or prevent bacterial or protozoal disease after transplantation. In Section VI, Dr. Sullivan reviews vaccine-preventable infections and guidelines for active and passive immunizations for stem cell transplant recipients, family members and health care workers.