Caspofungin

Pharmacological management of invasive mold infections in solid organ transplant recipients

INTRODUCTION

Solid organ transplant (SOT) recipients face an increased susceptibility to invasive fungal infection (IFI) due to filamentous fungi. Post-transplant invasive aspergillosis (IA) and mucormycosis are related to exceedingly high mortality rates and graft loss risk, and its management involve a unique range of clinical challenges.

AREAS COVERED

First, the current treatment recommendations for IA and mucormycosis among SOT recipients are critically reviewed, including the supporting evidence. Next, we discussed particular concerns in this patient population, such as drug-drug interactions (DDIs) between triazoles and post-transplant immunosuppression or treatment-related toxicity. The role for immunomodulatory and host-targeted therapies is also considered, as well as the theoretical impact of the intrinsic antifungal activity of calcineurin inhibitors. Finally, a personal opinion is made on future directions in the pharmacological approach to post-transplant IFI.

EXPERT OPINION

Despite relevant advances in the treatment of mold IFIs in the SOT setting, such as the incorporation of isavuconazole (with lower incidence of DDIs and better tolerability than voriconazole), there remains a large room for improvement in areas such as the position of combination therapy or the optimal strategy for the reduction of baseline immunosuppression. Importantly, future studies should define the specific contribution of newer antifungal agents and classes.

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.

Lower Concentrations of Amphotericin B Combined with Ent-Hardwickiic Acid Are Effective against Candida Strains

Life-threatening Candida infections have increased with the COVID-19 pandemic, and the already limited arsenal of antifungal drugs has become even more restricted due to its side effects associated with complications after SARS-CoV-2 infection. Drug combination strategies have the potential to reduce the risk of side effects without loss of therapeutic efficacy. The aim of this study was to evaluate the combination of ent-hardwickiic acid with low concentrations of amphotericin B against Candida strains. The minimum inhibitory concentration (MIC) values were determined for amphotericin B and ent-hardwickiic acid as isolated compounds and for 77 combinations of amphotericin B and ent-hardwickiic acid concentrations that were assessed by using the checkerboard microdilution method. Time–kill assays were performed in order to assess the fungistatic or fungicidal nature of the different combinations. The strategy of combining both compounds markedly reduced the MIC values from 16 µg/mL to 1 µg/mL of amphotericin B and from 12.5 µg/mL to 6.25 µg/mL of ent-hardwickiic acid, from isolated to combined, against C. albicans resistant to azoles. The combination of 1 µg/mL of amphotericin B with 6.25 µg/mL of ent-hardwickiic acid killed all the cells of the same strain within four hours of incubation.

Prevalence, Antifungal Susceptibility and Etiology of Vulvovaginal Candidiasis in Sub-Saharan Africa: A Systematic Review with Meta-analysis and Meta-regression

Vulvovaginal candidiasis (VVC) is a commonly occurring form of mucocutaneous candidiasis in women. The aim of this study was to comprehensively investigate the prevalence, antifungal susceptibility, and etiology of VVC in sub-Saharan Africa (SSA). A search of studies was conducted in seven online databases and the reference lists of selected studies. Observational studies published between January 2000, to July 2021, that met the eligibility criteria were included. Meta-analyses with random and fixed-effects model, and subgroup analyses were performed using STATA 16.0. A total of 41 studies including 15 723 participants were included in the meta-analyses. The pooled prevalence of VVC was 33% (95% Confidence Interval (CI): 28 - 38%, I2 = 98%, p < 0.001). Pregnant women had 6% higher odds of having VVC compared to non-pregnant women (Odds Ratio (OR): 1.06, 95% CI: 0.99 - 1.13, p = 0.107). The odds of diagnosing VVC were 40% higher in symptomatic patients than general study population (OR: 1.4, 95% CI: 1.3 - 1.5, p < 0.0001). In 17 studies, a total of 2112 isolates of Candida species were reported: 1514 (71.7%) C. albicans, 510 (24.1%) non-albicans Candida (NAC) species and 88 (4.2%) unidentified Candida spp. Of the NAC species detected, C. glabrata (40.9%, n = 209), C. krusei (21.2%, n = 108) and C. tropicalis (22.7%, n = 116) were the most common. Resistance to fluconazole in C. albicans using disc diffusion methods ranged from 6.8% in Cameroon to 53.7% in Ethiopia. One-third of women in SSA have VVC, mainly caused by C. albicans. Data on the susceptibility of the Candida isolates to commonly used antifungal agents is limited and warrants further research.

Echinocandins - structure, mechanism of action and use in antifungal therapy

With increasing number of immunocompromised patients as well as drug resistance in fungi, the risk of fatal fungal infections in humans increases as well. The action of echinocandins is based on the inhibition of β-(1,3)-d-glucan synthesis that builds the fungal cell wall. Caspofungin, micafungin, anidulafungin and rezafungin are semi-synthetic cyclic lipopeptides. Their specific chemical structure possess a potential to obtain novel derivatives with better pharmacological properties resulting in more effective treatment, especially in infections caused by Candida and Aspergillus species. In this review we summarise information about echinocandins with closer look on their chemical structure, mechanism of action, drug resistance and usage in clinical practice. We also introduce actual trends in modification of this antifungals as well as new methods of their administration, and additional use in viral and bacterial infections.

Striking Back against Fungal Infections: The Utilization of Nanosystems for Antifungal Strategies

Fungal infections have become a major health concern, given that invasive infections by Candida, Cryptococcus, and Aspergillus species have led to millions of mortalities. Conventional antifungal drugs including polyenes, echinocandins, azoles, allylamins, and antimetabolites have been used for decades, but their limitations include off-target toxicity, drug-resistance, poor water solubility, low bioavailability, and weak tissue penetration, which cannot be ignored. These drawbacks have led to the emergence of novel antifungal therapies. In this review, we discuss the nanosystems that are currently utilized for drug delivery and the application of antifungal therapies.

The antifungal activity of caspofungin in combination with antifungals or non-antifungals against Candida species in vitro and in clinical therapy

Introduction: Candida species have been regarded as global health threats due to their ability to cause invasive infections. It is challenging to treat Candida bloodstream infections, which are associated with high mortality levels. Monotherapy with antifungals is sometimes not effective against severe Candida infections, and combination therapy is needed in clinical practice.Areas covered: This review was undertaken based on data from a PubMed search for English language reports published before March 2021 by using the terms 'caspofungin,' 'Candida species,' 'combination therapy,' 'antifungal effect,' and 'novel antifungal agent.'Expert opinion: Combination therapy is an empirical strategy for treating refractory Candida infections. Caspofungin has been recommended to treat candidaemia. Caspofungin in combination therapy has some applications, while the efficacy of combination therapy in the treatment of refractory Candida infections needs more study, such as randomized controlled trials. In addition, novel compounds or drugs with potential antifungal activities have been examined, and some of them exhibit synergistic interactions with caspofungin. Thus, the antifungal activity of caspofungin in combination with antifungals or non-antifungals against Candida species in vitro and in clinical therapy is summarized.

Efficacy and mechanism of actions of natural antimicrobial drugs

Microbial infections have significantly increased over the last decades, and the mortality rates remain unacceptably high. The emergence of new resistance patterns and the spread of new viruses challenge the eradication of infectious diseases. The declining efficacy of antimicrobial drugs has become a global public health problem. Natural products derived from natural sources, such as plants, animals, and microorganisms, have significant efficacy for the treatment of infectious diseases accompanied by less adverse effects, synergy, and ability to overcome drug resistance. As the Chinese female scientist Youyou Tu received the Nobel Prize for the antimalarial drug artemisinin, antimicrobial drugs developed from Traditional Chinese Medicine are expected to receive increasing attention again. This review summarizes the antimicrobial agents derived from natural products approved for nearly 20 years and describes their efficacy and mode of action. The aim of this unit is to review the current status of antimicrobial drugs from natural products in order to increase the value of natural products as a source of novel drug candidates for infectious diseases.

Caspofungin: a review of its characteristics, activity, and use in intensive care units

INTRODUCTION

Candidemia is the fourth frequent reason of healthcare-related bloodstream infections in critically ill patients. For initial management of (suspected) invasive candidiasis in critically ill patients, usage of an echinocandin, e.g. caspofungin, has been recommended.

AREAS COVERED

In this study, characteristics of caspofungin and its use in intensive care unit (ICU) patients are reviewed based on an electronic search using PubMed and Google scholar.

EXPERT OPINION

Caspofungin is a semisynthetic derivative from pneumocandin B and the first member of the echinocandins that was approved by the U.S. Food and Drug Administration (FDA) to fight fungal infection. Caspofungin inhibits the enzyme β(1,3)-D-glucan synthase of the fungal cell wall resulted in inhibition of the synthesis of β(1,3)-D-glucan. For critically ill patients, inter- and intraindividual variations affect the caspofungin concentration. The incidence rates and densities of candidemia in surgical ICUs may be higher than medical ICUs resulting in a higher burden of candidemia in surgical ICUs. However, the mortality rate in surgical ICU patients with candidemia is higher than that medical ICU patients due to differences in their underlying conditions.

Nanoscopic cell-wall architecture of an immunogenic ligand in Candida albicans during antifungal drug treatment

Candida albicans evades immunity by limiting cell-wall β-glucan exposure. dSTORM imaging reveals that “unmasking”of glucan by an antifungal drug occurs through nanoscale reorganization of glucan exposure geometry. Nanostructuring of glucan might play a role in innate immune activation and provides insights into the physical regulation of glucan exposure.

The cell wall of Candida albicans is composed largely of polysaccharides. Here we focus on β-glucan, an immunogenic cell-wall polysaccharide whose surface exposure is often restricted, or “masked,” from immune recognition by Dectin-1 on dendritic cells (DCs) and other innate immune cells. Previous research suggested that the physical presentation geometry of β-glucan might determine whether it can be recognized by Dectin-1. We used direct stochastic optical reconstruction microscopy to explore the fine structure of β-glucan exposed on C. albicans cell walls before and after treatment with the antimycotic drug caspofungin, which alters glucan exposure. Most surface-accessible glucan on C. albicans yeast and hyphae is limited to isolated Dectin-1–binding sites. Caspofungin-induced unmasking caused approximately fourfold to sevenfold increase in total glucan exposure, accompanied by increased phagocytosis efficiency of DCs for unmasked yeasts. Nanoscopic imaging of caspofungin-unmasked C. albicans cell walls revealed that the increase in glucan exposure is due to increased density of glucan exposures and increased multiglucan exposure sizes. These findings reveal that glucan exhibits significant nanostructure, which is a previously unknown physical component of the host–Candida interaction that might change during antifungal chemotherapy and affect innate immune activation.

Evaluation of culture media for the production of secondary metabolites in a natural products screening program

Variation in the growing environment can have significant impacts on the quantity and diversity of fungal secondary metabolites. In the industrial setting, optimization of growing conditions can lead to significantly increased production of a compound of interest. Such optimization becomes challenging in a drug-discovery screening situation, as the ideal conditions for one organism may induce poor metabolic diversity for a different organism. Here, the impact of different media types, including six liquid media and five solid media, on the secondary metabolite production of three fungal strains was examined in the context of the drug-discovery screening process. The relative production of marker compounds was used to evaluate the usefulness and reliability of each medium for the purpose of producing secondary metabolites.

Characterization and phylogenetic analysis of the mitochondrial genome of Glarea lozoyensis indicates high diversity within the order Helotiales

BACKGROUND

Glarea lozoyensis is a filamentous fungus used for the industrial production of non-ribosomal peptide pneumocandin B0. In the scope of a whole genome sequencing the complete mitochondrial genome of the fungus has been assembled and annotated. It is the first one of the large polyphyletic Helotiaceae family. A phylogenetic analysis was performed based on conserved proteins of the oxidative phosphorylation system in mitochondrial genomes.

RESULTS

The total size of the mitochondrial genome is 45,038 bp. It contains the expected 14 genes coding for proteins related to oxidative phosphorylation,two rRNA genes, six hypothetical proteins, three intronic genes of which two are homing endonucleases and a ribosomal protein rps3. Additionally there is a set of 33 tRNA genes. All genes are located on the same strand. Phylogenetic analyses based on concatenated mitochondrial protein sequences confirmed that G. lozoyensis belongs to the order of Helotiales and that it is most closely related to Phialocephala subalpina. However, a comparison with the three other mitochondrial genomes known from Helotialean species revealed remarkable differences in size, gene content and sequence. Moreover, it was found that the gene order found in P. subalpina and Sclerotinia sclerotiorum is not conserved in G. lozoyensis.

CONCLUSION

The arrangement of genes and other differences found between the mitochondrial genome of G. lozoyensis and those of other Helotiales indicates a broad genetic diversity within this large order. Further mitochondrial genomes are required in order to determine whether there is a continuous transition between the different forms of mitochondrial genomes or G. lozoyensis belongs to a distinct subgroup within Helotiales.

Pharmacologically prospective antibiotic agents and their sources: a marine microbial perspective

Marine microbes have been a storehouse of bioactive metabolites with tremendous potential as drug candidates. Marine microorganism derived secondary metabolites (chemical compounds/peptides) are considered to be a burning area of research since recent past. Many of such compounds have been proven to be anti-bacterial, anti-fungal, anti-algal, anti-HIV, anti-helminthic, anti-protozoan, anti-tumor and anti-allergic agents. Marine bacteria and fungi have been reported to be the producers of such compounds owing to their defense mechanisms and metabolic by products. Although the number of natural products isolated from these classes of marine microbial flora is large, a limited number of such compounds reach the clinical trial and even less number of them get approved as a drug. Here we discuss the recent studies on the isolation, characterization and the pharmacological significances of anti-bacterial, anti-fungal and anti-infective agents of marine microbial origin. Further, the clinical status of such compounds has also been discussed in comparison with those derived from their terrestrial counterparts.

Total synthesis and structure-activity relationships of new echinocandin-like antifungal cyclolipohexapeptides

A series of new echinocandin-like cyclolipohexapeptides were designed and total synthesized via solution phase [3 + 3]-segment coupling strategy with an attempt to improve antifungal activity. The designed compounds showed potent antifungal activities with broad spectrum. In particular, 11 compounds (i.e. 28a-e, 28g, 28i-j, 29a, 29c and 29e) showed better in vitro antifungal activities against Candida albicans or Aspergillus fumigatus than caspofungin. Moreover, the synthesized compounds provided new SAR information for the echinocandins. The findings in this work suggested that the "left" tripeptide segment of cyclolipohexapeptide scaffold might be a hydrophilic structural motif, whereas the "right" lipopeptide segment was preferred as a hydrophobic core. The amino acid component of the cyclolipohexapeptide scaffold could significantly affect the SAR of the side chains.

Implant infection after augmentation mammaplasty: a review of the literature and report of a multidrug-resistant Candida albicans infection

BACKGROUND

Implant breast augmentation is one of the most frequently performed surgical procedures, and fungal infection still is considered exceptional. This report presents a case of bilateral breast implant infection by multidrug-resistant Candida albicans treated with a targeted antifungal therapy.

METHODS

A young woman presented with breast pain and asymmetry as well as implant superficialization in the left breast 3 years after bilateral tuberous breast correction with implant insertion. She did not report any trauma to the chest wall or recent systemic infections. The breast was evaluated through mammary compliance analysis and magnetic resonance imaging (MRI).

RESULTS

At surgery, both implants showed capsule contracture and were surrounded by a gelatinous yellow-brown and turbid fluid, which was sent for microbial and fungal analysis. A bilateral capsulectomy was performed. After copious irrigation of the subglandular pockets, submuscular pockets were created, and implants were substituted. Culture swabs tested positive for C. albicans and showed drug resistance to amphotericin B, fluconazole, itraconazole, and voriconazole on the fungal antibiogram. Targeted antifungal therapy with caspofungin was administrated in association with oral antibiotic therapy. Follow-up assessment at 1, 3, 6, 12, and 24 months did not show any infection or contracture relapse.

CONCLUSIONS

This is the first report in the literature on a breast implant infection by a multidrug-resistant C. albicans. The study focused on the association between fungal contamination and capsular contracture and investigated the importance of a fungal antibiogram in cases of suspected prosthesis infection for performance of a targeted antifungal treatment.

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.

[Cost effectiveness of posaconazole versus fluconazole/itraconazole in the prophylactic treatment of invasive fungal infections in Mexico]

Cost effectiveness of posaconazole versus fluconazole/itraconazole therapy in the prophylaxis against invasive fungal Infections among high-risk neutropenic patients in Mexico.

OBJECTIVE

To estimate the cost effectiveness and long-term combined effects of Posaconazole versus fluconazole/itraconazole (standard azole) therapy in the prophylaxis against invasive fungal Infections among high-risk neutropenic patients in Mexico.

METHODS

A previously validated Markov model was used to compare the projected lifetime costs and effects of two theoretical groups of patients, one receiving Posaconazole and the other receiving standard azole. The model estimates total costs, numbers of IFIs, and QALY per patient in each prophylaxis group. To extrapolate trial results to a lifetime horizon, the model was extended with one-month Markov cycles in which mortality risk is specific to the underlying disease. Data on the probabilities of IFI were obtained from Study Protocol PO1899. Drug costs were taken from average wholesale drug reports for 2009. Cost and health effects were discounted at 5% according to the Mexican guideline. The analysis was conducted from the Mexican healthcare perspective using 2008 unit cost prices.

RESULTS

Our model projects an accumulated cost to the Mexican healthcare system per patient receiving the Posaconazol regimen of $US 5,634 compared to $US 7,463 for the standard azole regimen. The accumulated discounted effect is 3.13 LY or 2.25 QALYs per patient receiving Posaconazol, compared to 2.96 LY or 2.13 QALYs per patient receiving standard azole. Posaconazol remained the dominant strategy across each scenario. Probabilistic sensitivity analysis tested numerous assumptions about the model cost and efficacy parameters and found that the results were robust to most changes.

CONCLUSION

Posaconazole provides modest incremental benefits compared with standard azole therapy in the prophylaxis against IFIs among high-risk neutropenic patients. Routine Posaconazole use appears a cost saving when the likelihood of IFIs or the cost of treatment medications is high.

Caspofungin: when and how? The microbiologist's view

The echinocandins are antifungal agents, which act by inhibiting the synthesis of β-(1,3)-D-glucan, an integral component of fungal cell walls. Caspofungin, the first approved echinocandin, demonstrates good in vitro and in vivo activity against a range of Candida species and is an alternative therapy for Aspergillus infections. Caspofungin provides an excellent safety profile and is therefore favoured in patients with moderately severe to severe illness, recent azole exposure and in those who are at high risk of infections due to Candida glabrata or Candida krusei. In vivo/in vitro resistance to caspofungin and breakthrough infections in patients receiving this agent have been reported for Candida and Aspergillus species. The types of pathogens and the frequency causing breakthrough mycoses are not well delineated. Caspofungin resistance resulting in clinical failure has been linked to mutations in the Fksp subunit of glucan synthase complex. European Committee for Antimicrobial Susceptibility Testing and Clinical and Laboratory Standards Institute need to improve the in vitro susceptibility testing methods to detect fks hot spot mutants. Caspofungin represents a significant advance in the care of patients with serious fungal infections.

Caspofungin: in pediatric patients with fungal infections

Caspofungin is the first echinocandin to be approved for the treatment of fungal infections in pediatric patients. The antifungal properties of caspofungin result from interference with fungal cell-wall integrity. In vitro, caspofungin is fungicidal against Candida spp. and fungistatic against Aspergillus spp., but has little or no fungicidal or fungistatic activity against Cryptococcus neoformans, the Zygomycetes, Fusarium spp., or Trichosporon beigelii. Caspofungin was effective as empirical antifungal therapy in pediatric patients with persistent fever and neutropenia. Almost half (46%) of caspofungin recipients and one-third (32%) of liposomal amphotericin B recipients achieved an overall favorable response in a randomized, double-blind trial. Caspofungin was also effective in pediatric patients with fungal infections (invasive candidiasis, invasive aspergillosis refractory to or intolerant of standard antifungal agents, or esophageal candidiasis). Positive responses to treatment were seen in 30 of 37 patients with invasive candidiasis, 5 of 10 patients with invasive aspergillosis, and in the one patient with esophageal candidiasis, in a noncomparative, open-label trial. Caspofungin was generally well tolerated in the clinical trials in pediatric patients with febrile neutropenia requiring empirical antifungal treatment, or with fungal infections. Few caspofungin recipients reported serious drug-related adverse events or discontinued treatment as a result of drug-related adverse events.

[Future role of micafungin in the treatment of invasive mycoses caused by filamentous fungi]

BACKGROUND

Micafungin is a echinocandin. It inhibits beta-1,3-D-glucan synthesis, thus achieving fungicidal activity against virtually all Candida spp., including those resistant to fluconazole, and fungistatic activity against Aspergillus spp., as well as several but not all pathogenic molds. Results from in vitro studies, animal models, small clinical trials, hint at possible future indications such as invasive aspergillosis and empirical viantifungal therapy, although currently there is little information published.

AIMS

To describe published data of micafungin as treatment against invasive mold infections, specially analysing its role in the inmunodepressed host and critical care setting.

METHODS

A systematic review of literature using the principal medical search engines was performed. Terms such as micafungin, aspergillosis, zygomycosis, invasive fungal infections, emerging fungal infections, antifungal treatment or therapy, antifungal prophylaxis, empiric or pre-emptive therapy were crossed. Febrile neutropenia patients were excluded.

RESULTS

Several studies in these setting were identified and were described in this review. Although there were no blinded randomized clinical trials published, treatment or prophylaxis of invasive aspergillosis and other invasive mould infections with micafungin described in open clinical studies were analyzed.

CONCLUSIONS

Micafungin could play a future important role as a primary or rescue therapy, alone or in combination, in the treatment or prophylaxis of invasive fungal infections caused by moulds. New randomized clinical trials are needed to confirm their efficacy.

Peptide antibiotics: an alternative and effective antimicrobial strategy to circumvent fungal infections

Mycosis, caused by both filamentous fungi and pathogenic yeasts is a major concern nowadays especially in the immunocompromised patient population. The emergence of pathogenic fungi resistant to current therapies in the last few decades has intensified the search for new antifungals like cationic peptides, which are the key components of innate defense mechanism. The review provides an inventory of different peptides from a diverse array of organisms from bacteria to mammals with proven antifungal activity, their therapeutic options and also about those which are in various stages of preclinical development. Literature, on the total and semi-synthetic variants of the parent peptides that exhibit an improved antifungal activity is also reviewed.

Recent advances and challenges in the treatment of invasive fungal infections

The frequency of invasive fungal infections (IFIs) has increased over the last decade with the rise in at-risk populations of patients. The morbidity and mortality of IFIs are high and management of these conditions is a great challenge. With the widespread adoption of antifungal prophylaxis, the epidemiology of invasive fungal pathogens has changed. Non-albicans Candida, non-fumigatus Aspergillus and moulds other than Aspergillus have become increasingly recognised causes of invasive diseases. These emerging fungi are characterised by resistance or lower susceptibility to standard antifungal agents. Invasive infections due to these previously rare fungi are therefore more difficult to treat. Recently developed antifungal agents provide the potential to improve management options and therapeutic outcomes of these infections. The availability of more potent and less toxic antifungal agents, such as second-generation triazoles and echinocandins, has led to considerable improvement in the treatment of IFIs. This article reviews the changing spectrum of invasive mycosis, the properties of recently developed antifungal agents and their role in the management of these infections.

Micafungin sodium, the second of the echinocandin class of antifungals: theory and practice

Micafungin is a new drug in the echinocandin class and is currently being investigated in Phase III clinical trials. Like other echinocandins, it inhibits 1,3-beta-D-glucan synthesis, thus achieving fungicidal activity against virtually all Candida spp., including those resistant to fluconazole, and fungistatic activity against Aspergillus spp. Micafungin sodium is available for intravenous administration only. It has a favorable safety and drug-drug interaction profile. Micafungin has been approved by the US FDA for treatment of esophageal candidiasis and for antifungal prophylaxis during the pre-engraftment phase in patients undergoing hematopoietic stem cell transplantation. Considering the competitive pricing as well as the good tolerability and efficacy, at present micafungin seems to be another choice for both of these indications. Current research has proven micafungin sodium to add a rational and effective option to the antifungal armamentarium, especially in esophageal candidiasis refractory to fluconazole treatment, in those intolerant to triazoles or in patients needing concomitant therapy interacting with triazoles. In addition to the current indications, recent uncontrolled clinical trials have demonstrated a marked success in the treatment of candidemia and invasive candidiasis. Results from in vitro studies, animal models, small clinical trials, as well as the obvious comparison with the more established caspofungin, hint at possible future indications such as invasive aspergillosis and empirical antifungal therapy. However, preclinical data on micafungin is inconsistent and published well-designed clinical studies are scarce. More controlled and sufficiently scaled trials are imperative in order to establish micafungin as a reliable and safe option in clinical practice.

Voriconazole : a review of its use in the management of invasive fungal infections

Voriconazole (VFEND), a synthetic second-generation, broad-spectrum triazole derivative of fluconazole, inhibits the cytochrome P450 (CYP)-dependent enzyme 14-alpha-sterol demethylase, thereby disrupting the cell membrane and halting fungal growth. In the US, intravenous and/or oral voriconazole is recommended in adults for the treatment of invasive aspergillosis, candidaemia in non-neutropenic patients, disseminated infections caused by Candida spp., oesophageal candidiasis, and in patients with scedosporiosis and fusariosis who are refractory to or intolerant of other antifungal therapy. In Europe, intravenous and/or oral voriconazole is recommended in adults and paediatric patients of at least 2 years of age for the treatment of invasive aspergillosis, candidaemia in non-neutropenic patients, fluconazole-resistant serious invasive Candida spp. infections, scedosporiosis and fusariosis. In large randomised trials, voriconazole was an effective and generally well tolerated primary treatment for candidiasis and invasive aspergillosis in adults and adolescents. More limited data also support the use of voriconazole for the treatment of invasive fungal infections in children, in those with rare fungal infections, such as Fusarium spp. or Scedosporium spp., and in those refractory to or intolerant of other standard antifungal therapies. The availability of both parenteral and oral formulations and the almost complete absorption of the drug after oral administration provide for ease of use and potential cost savings, and ensure that therapeutic plasma concentrations are maintained when switching from intravenous to oral therapy. On the other hand, the numerous drug interactions associated with voriconazole may limit its usefulness in some patients. Further clinical experience will help to more fully determine the position of voriconazole in relation to other licensed antifungal agents. In the meantime, voriconazole is a valuable emerging option for the treatment of invasive aspergillosis and rare fungal infections, including Fusarium spp. and Scedosporium spp. infections, and provides an alternative option for the treatment of candidiasis, particularly where the causative organism is inherently resistant to other licensed antifungal agents.

Anidulafungin ? state of affairs from a clinical perspective

Anidulafungin is the most recent development in the echinocandin class antifungals. Like other echinocandins, it inhibits 1,3-beta-d-glucan synthesis, thus achieving fungicidal activity against many Candida spp. including those resistant to fluconazole as well as fungistatic activity against some clinically important filamentous fungi, especially Aspergillus spp. The drug is well tolerated, even in patients with renal or hepatic impairment. It has a low drug-drug interaction profile as it does not significantly interfere with the cytochrome P450 pathway. Anidulafungin has been approved for treatment of candidaemia, intra-abdominal abscesses, peritonitis and oesophageal candidiasis. Trials have shown non-inferiority of anidulafungin to fluconazole in the treatment of invasive and non-invasive candidiasis. After promising results from animal models, the role of anidulafungin in the treatment of invasive aspergillosis and other filamentous fungi is yet to be cleared. Currently, anidulafungin offers another alternative in the treatment of Candida infections, especially in patients where avoidance of drug-drug interactions is needed. Future investigations may elucidate how anidulafungin performs clinically in comparison with the other echinocandins.

Caspofungin for the treatment of fungal infections: a systematic review of randomized controlled trials

During the last decade, owing to the low effectiveness and high toxicity of older antifungals, new antifungal agents have been released to the market for the treatment of patients with fungal infections. Several randomized controlled trials (RCTs) have been designed to evaluate the effectiveness of caspofungin in comparison with other antifungal agents. This review was conducted to examine further the role of caspofungin in the treatment of patients with fungal, mainly Candida, infections. Two reviewers independently performed the literature search, study selection and data extraction from relevant RCTs. A total of six RCTs comparing caspofungin with amphotericin B (deoxycholate in four and liposomal in one RCT) or fluconazole (in one RCT), which studied a total of 1974 patients, were included in our review. Success of the applied treatment in the clinically evaluable patients was achieved in 496/943 (52.6%) of the caspofungin-treated patients and in 381/852 (44.7%) of the amphotericin B- and lipid amphotericin B-treated patients. Discontinuation due to drug toxicity was significantly less common in patients receiving caspofungin than amphotericin B (odds ratio (OR) 0.25, 95% confidence interval (CI) 0.07-0.85, random effects model). Development of nephrotoxicity, hypokalaemia and fever also occurred significantly less often with caspofungin than amphotericin B (OR 0.23, 95% CI 0.14-0.36, fixed effects model; OR 0.3, 95% CI 0.12-0.76, random effects model; and OR 0.26, 95% CI 0.08-0.79, random effects model, respectively). No difference in mortality was noted. Caspofungin was associated with better clinical outcomes (higher cure and fewer adverse effects) than amphotericin B in the treatment of patients with fungal infections.

Antifungal activity of C-27 steroidal saponins

As part of our search for new antifungal agents from natural resources, 22 C-27 steroidal saponins and 6 steroidal sapogenins isolated from several monocotyledonous plants were tested for their antifungal activity against the opportunistic pathogens Candida albicans, Candida glabrata, Candida krusei, Cryptococcus neoformans, and Aspergillus fumigatus. The results showed that the antifungal activity of the steroidal saponins was associated with their aglycone moieties and the number and structure of monosaccharide units in their sugar chains. Within the 10 active saponins, four tigogenin saponins (compounds 1 to 4) with a sugar moiety of four or five monosaccharide units exhibited significant activity against C. neoformans and A. fumigatus, comparable to the positive control amphotericin B. The antifungal potency of these compounds was not associated with cytotoxicity to mammalian cells. This suggests that the C-27 steroidal saponins may be considered potential antifungal leads for further preclinical study.

Evaluation of antifungals in the surgical intensive care unit: a multi-institutional study

In the USA, >50% of candidemia episodes occur in medical or surgical intensive care units (SICU). However, studies focused on patterns and rationale for antifungal use are lacking. The objective of this study was to evaluate systemic antifungal usage in SICU patients. Retrospective audit of SICU patients receiving antifungal therapy from four American hospitals. Medical records were reviewed for demographics, hospital variables, microbiology results, antifungal regimens and indications for therapy. A total of 2411 patient-days of antifungal use were evaluated in 225 patients. Fluconazole was the most frequently prescribed antifungal (1846 patient-days) followed by amphotericin B deoxycholate (251 patient-days), lipid formulations of amphotericin B (201 patient-days), itraconazole (71 patient-days), and caspofungin (42 patient-days). Antifungals were prescribed empirically (44%), for preemptive therapy in critically ill patients colonised with Candida (43%), or for candidiasis (12%). Candida species were recovered from 98% of patients with positive fungal cultures most commonly from pulmonary (53%) or urinary sources (17%). Fluconazole is the most frequently prescribed antifungal agent in SICUs and is most often prescribed for empiric or preemptive indications. Research efforts to identify patients who warrant preemptive antifungal therapy for invasive candidiasis could dramatically change antifungal prescribing patterns in the SICU.

Drug discovery from natural sources

Organic compounds from terrestrial and marine organisms have extensive past and present use in the treatment of many diseases and serve as compounds of interest both in their natural form and as templates for synthetic modification. Over 20 new drugs launched on the market between 2000 and 2005, originating from terrestrial plants, terrestrial microorganisms, marine organisms, and terrestrial vertebrates and invertebrates, are described. These approved substances, representative of very wide chemical diversity, together with several other natural products or their analogs undergoing clinical trials, continue to demonstrate the importance of compounds from natural sources in modern drug discovery efforts.

Treatment with caspofungin in immunocompromised paediatric patients: a multicentre survey

OBJECTIVES

Although a paediatric dosage has not been established, caspofungin is occasionally used in paediatric patients. We conducted a multicentre retrospective survey to obtain data on immunocompromised paediatric patients considered to require caspofungin therapy.

METHODS

The survey identified 64 patients (median age: 11.5 years; 25 females, 39 males) with haematological malignancies (48), marrow failure (9), solid tumours (3), haematological disorders (2) and congenital immunodeficiency (2) who received caspofungin for proven (17), probable (14) and possible (17) invasive fungal infections or empirically (16). Caspofungin was administered until intolerance or maximum efficacy at dosages individually determined by the responsible physician for refractory infection (38), intolerance of other agents (10) or as best therapeutic option (16).

RESULTS

The 64 patients received caspofungin for a median of 37 days (range 3-218) as single agent (20) or in combination (44). The median daily maintenance dosage was 1.07 mg/kg (95% CI 1.09-1.35; range 0.40-2.92) or 34.3 mg/m2 (95% CI 32.3-37.3; range 16.3-57.5). In none of the patients was therapy discontinued due to adverse events (AEs). Clinical AEs were mild to moderate and observed in 34 patients (53.1%). While mean glutamate pyruvate transaminase and glutamate oxalate transaminase values were slightly (P < 0.005) higher at the end of treatment (EOT), serum bilirubin, alkaline phosphatase and creatinine values were not different from baseline. Complete responses, partial responses or stabilization were observed in 5/7/3 of 17 patients with proven, in 3/4/3 of 14 patients with probable and in 7/6/1 of 15 evaluable patients with possible invasive infections. Thirteen of 16 patients on empirical therapy completed without breakthrough infection. Overall survival was 75% at the EOT and 70% at 3 months post-EOT, respectively.

CONCLUSIONS

Caspofungin displayed favourable safety and tolerance and may have useful antifungal efficacy in severely immunocompromised paediatric patients.

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.

Experience with caspofungin in the treatment of persistent fungemia in neonates

OBJECTIVE

To review our experience of caspofungin in the treatment of persistent candidemia in the neonatal intensive care unit.

STUDY DESIGN

This was a retrospective chart review on 13 infants in whom caspofungin was added to conventional antifungals (amphotericin B and/or fluconazole or flucytosine) for the treatment of refractory candidemia.

RESULTS

A total of 12 infants were preterm (gestational age, 24 to 28 weeks) and one was term; the median birth weight was 800 g (range, 530 to 5600 g). Candidemia (Candida albicans in five, C. parapsilosis in six, C. albicans and C. parapsilosis in one and C. tropicalis in one) persisted despite 6 to 30 days of conventional antifungal therapy. After the addition of caspofungin, sterilization of blood cultures was achieved in 11 infants at the median time of 3 days (range, 1 to 21 days). Adverse events included thrombophlebitis (one patient), hypokalemia (two patients) and elevation of liver enzymes (four patients). Three infants had a second episode of candidemia and seven patients died.

CONCLUSION

Caspofungin may be an efficacious addition for treatment of candidemia refractory to conventional antifungal therapy. This drug should be further investigated in neonates.

Pharmacological properties and clinical efficacy of a recently licensed systemic antifungal, caspofungin

Caspofungin, a semisynthetic derivative of the pneumocandin B(0), is the first licensed compound of a new class of antifungal agents, the echinocandins. It attacks the fungal cell by selective inhibition of the beta-(1,3)-d-glucan synthase, which is not present in mammalian cells. In vitro studies have indicated a potent fungicidal effect on Candida species, and in vivo studies in immunocompromised animals with invasive candidiasis demonstrated a favourable outcome. In randomized clinical trials in patients with oropharyngeal/oesophageal and invasive candidiasis, caspofungin was at least as effective as amphotericin B deoxycholate, yet showed a significantly superior safety profile. Of patients with invasive aspergillosis refractory to or intolerant of other antifungal agents, 45% showed a partial or complete response to caspofungin given as a salvage treatment. Also, it demonstrated comparable clinical efficacy but superior tolerability in the empirical antifungal therapy in neutropenic patients compared with liposomal amphothericin B. Caspofungin has an excellent tolerability and a low potential for drug interactions. Thus, caspofungin represents an interesting and clinically valuable new antifungal drug that broadens the available therapeutic armamentarium for the treatment of invasive fungal infections.

Caspofungin as first line therapy of pulmonary invasive fungal infections in 32 immunocompromised patients with hematologic malignancies

Invasive Fungal Infections (IFI) remain a severe and major complication among patients with hematologic diseases, but the recent availability of new antifungal agents (echinocandins and new azoles) have improved the chance of cure. Caspofungin (Cancidas-Merck) is a large lipopeptide molecule able to inhibit the enzyme complex 1,3-d-glucan synthetase; this action specifically damages the fungal cell wall. Caspofungin (CAS) is active, in vitro and in vivo, against most Candida species and Aspergillus species. We report on our experience with this drug as first-line therapy for proven or probable pulmonary IFI in immunocompromised patients with hematologic malignancies. Thirty-two consecutive patients (20 males and 12 females, with a median age of 52 yr) have been treated with CAS (27 acute leukemias, 1 chronic leukemia, 3 lymphomas and 1 multiple myeloma). Sixteen patients (50%) had a relapsed or resistant hematologic disease, while 12 patients were in complete remission and 4 were at onset of disease; 8/32 (25%) developed IFI after a hematopoietic stem cell transplant (HSCT) procedure. Seven out of 32 patients (22%) had a proven pulmonary IFI (7/7 Aspergillosis) and 25 (78%) had a probable IFI with pulmonary localization as defined according to international consensus. Thirty-one patients (97%) had less than 1000 granulocytes/mL at onset of infection and at the start of CAS therapy. The CAS was given at the dose of 70 mg on day 1, followed by 50 mg/day. Median duration of CAS therapy was 20 d (range 8-64); all the 31 neutropenic patients received concomitant granulocyte colony-stimulating factor (G-CSF). The overall response rate was 56% (18/32) with 12/18 complete responses and 6/18 partial responses; two patients (6%) had a stable disease. Twelve out of 32 (38%) did not respond and seven died of mycotic infection. Univariate analysis showed that granulocytes recovery (>500/mL vs. <500/mL) and status of hematologic disease (remission/onset vs. refractory/relapsed) were significantly associated to favourable outcome. No clinical adverse events (AE) were reported and only a grades I and II transient increase of serum alkaline phosphatase and/or transaminases occurred in 4/32 (12%) patients. After CAS therapy six non-responders and six cases with a partial or stable response were rescued with voriconazole. Two out of six patients (33%) in the former group and 6/6 (100%) in the latter obtained a complete resolution of IFI. Our experience suggests an efficacy of CAS, in combination with G-CSF, as first-line treatment of proven or probable IFI with pulmonary localization. The drug was well tolerated and there were no significant hepatic AE even in patients receiving CAS with cyclosporine after a HSCT. A significant proportion of non-responders or partial responders to CAS can be rescued with a subsequent voriconazole-based therapy.

Natural products to drugs: natural product derived compounds in clinical trials

Natural product and natural product-derived compounds that are being evaluated in clinical trials or in registration (current 31 December 2004) have been reviewed. Natural product derived drugs launched in the United States of America, Europe and Japan since 1998 and new natural product templates discovered since 1990 are discussed.

Native valve endocarditis due to Candida glabrata treated without valvular replacement: a potential role for caspofungin in the induction and maintenance treatment

Conventional antifungal therapy for fungal endocarditis has been associated with a poor cure rate. Therefore, combined medical and surgical therapy has been recommended. However, new potent antifungal agents, such as echinocandins, could increase the medical options and, in some cases, avoid the need for surgery. We report a case of Candida endocarditis treated successfully without valve replacement with intravenous liposomal amphotericin B (total dose, 4 g) and intravenous caspofungin (a 100-mg loading dose followed by 50 mg per day for 8 weeks) as induction therapy and intravenous caspofungin (100 mg 3 times per week for 12 weeks) as maintenance therapy.

In vitro activity of anidulafungin against selected clinically important mold isolates

In this study, we evaluated the in vitro activity of anidulafungin against selected mold isolates. Anidulafungin showed promising activity against Bipolaris spicifera, Exophiala jeanselmei, Fonsecaea pedrosoi, Madurella mycetomatis, Penicillium marneffei, Phialophora verrucosa, Pseudallescheria boydii, Sporothrix schenckii, and Wangiella dermatitidis.