Early clinical experience with anidulafungin at a large tertiary care medical center

Candida parapsilosis: from Genes to the Bedside

Patients with suppressed immunity are at the highest risk for hospital-acquired infections. Among these, invasive candidiasis is the most prevalent systemic fungal nosocomial infection. Over recent decades, the combined prevalence of non-albicans Candida species outranked Candida albicans infections in several geographical regions worldwide, highlighting the need to understand their pathobiology in order to develop effective treatment and to prevent future outbreaks. Candida parapsilosis is the second or third most frequently isolated Candida species from patients. Besides being highly prevalent, its biology differs markedly from that of C. albicans, which may be associated with C. parapsilosis' increased incidence. Differences in virulence, regulatory and antifungal drug resistance mechanisms, and the patient groups at risk indicate that conclusions drawn from C. albicans pathobiology cannot be simply extrapolated to C. parapsilosis Such species-specific characteristics may also influence their recognition and elimination by the host and the efficacy of antifungal drugs. Due to the availability of high-throughput, state-of-the-art experimental tools and molecular genetic methods adapted to C. parapsilosis, genome and transcriptome studies are now available that greatly contribute to our understanding of what makes this species a threat. In this review, we summarize 10 years of findings on C. parapsilosis pathogenesis, including the species' genetic properties, transcriptome studies, host responses, and molecular mechanisms of virulence. Antifungal susceptibility studies and clinician perspectives are discussed. We also present regional incidence reports in order to provide an updated worldwide epidemiology summary.

Antifungal prophylaxis with anidulafungin to minimize drug interactions with an antiepileptic treatment in a hematopoietic stem cell transplant recipient

WHAT IS KNOWN AND OBJECTIVE

Invasive fungal infections are a major cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). This provides a clear rationale for antifungal prophylaxis in this population. A concern is the potential for drug interactions, given that most of antifungals are metabolized through the P450 cytochrome system.

CASE SUMMARY

We present a case of a 33-year-old woman, with a past history of high-risk epilepsy, who underwent allogeneic HSCT for a myelodysplastic syndrome. Anidulafungin was successfully used as antifungal prophylaxis to minimize drug interactions with her antiepileptic treatment.

WHAT IS NEW AND CONCLUSION

This is the first reported case of antifungal prophylaxis with this echinocandin in HSCT. Anidulafungin may be an option in transplant recipients with multiple risk factors for drug interactions.

Treatment of invasive fungal disease using anidulafungin alone or in combination for hematologic patients with concomitant hepatic or renal impairment

BACKGROUND

Invasive fungal disease (IFD) treatment is challenging in hematologic patients due to drug interactions and toxicities that limit the use of the antifungal agents.

AIMS

To analyze retrospectively in terms of safety and potential efficacy anidulafungin therapy, alone or in combination.

METHODS

Our institutional guidelines recommended anidulafungin treatment in hematologic patients with suspected IFD and concomitant renal or liver impairment (to avoid drug interactions and preserve organ function).

RESULTS

From 2008 to 2013, 24 episodes of IFD occurring in 21 patients were classified as proven (4 cases), probable (15 cases) and possible (5 cases). Anidulafungin was administered alone (13%) or in combination (88%). Eight (33%) episodes were resolved, using monotherapy (1 out of 3, 33%) or a combined therapy (7 out of 21, 33%). Twelve cases (50%) were registered as failure (death due to IFD progression in 4 patients, and treatment change due to lack of efficacy in 8), and 4 cases (17%) were not evaluable (death unrelated to the IFD). Anidulafungin was not withdrawn in any case due to toxicity.

CONCLUSIONS

Anidulafungin therapy, alone or in combination, could be considered in hematologic patients with IFD and concomitant liver or renal impairment. Due to the low number of patients, we cannot draw any conclusion about efficacy.

Cost effectiveness of caspofungin vs. voriconazole for empiric therapy in Turkey

Invasive fungal infections from febrile neutropenia are associated with significant cost and mortality. The mainstay of treatment has been liposomal amphotericin B, however, echinocandins and azoles have shown promise as alternative treatments. Data on clinical efficacy exist, however, data incorporating pharmacoeconomic considerations are required in Turkey. The aim of this study was to investigate the cost effectiveness of caspofungin vs. voriconazole in empiric treatment of febrile neutropenia in Turkey. A decision analytic model was utilised, built upon two randomised-controlled trials and supplemented with expert panel input from clinicians in Turkey. A five-point composite outcome measure was utilised and sensitivity analyses were performed to demonstrate the robustness of the model. The base case scenario resulted in caspofungin being preferred by TL2,533, TL29,256 and TL2,536 per patient treated, successfully treated patient and patient survival, respectively (approx. USD1414, 16 328 and 1415); sensitivity analyses did not change the outcome. Monte Carlo simulation highlighted a 78.8% chance of favouring caspofungin. The result was moderately sensitive to treatment duration and acquisition cost of the antifungal agents compared. This is the first pharmacoeconomic study comparing caspofungin to voriconazole within Turkey, resulting in an advantage towards caspofungin. The study will aid in formulary decision-making based on the clinical and economic consequences of each agent in the Turkish health care setting.

Pharmacoeconomic evaluation of voriconazole vs. liposomal amphotericin B in empiric treatment of invasive fungal infections in Turkey

Background

Invasive fungal infections (IFI) are associated with considerable expense and mortality on healthcare systems. There is a need to provide evidence of both clinical efficacy and value for money with any health technology. The current pharmacoeconomic evaluation investigated the use of liposomal amphotericin B (LAmB) and voriconazole for the empiric treatment of IFI in the Turkish setting.

Methods

Decision analytic modelling was used to create a pathway for patient treatment with a 5-point composite outcome measure. The data was obtained from a major non-inferiority multicentre randomised controlled study, with an expert panel of clinicians in Turkey providing transition probabilities and cost not available in the literature. Sensitivity analyses were performed on the inputs from the clinical trial and the expert panel.

Results

As per the base case analysis, voriconazole was preferred by Turkish Lira (TL) 2,523 per patient treated and TL2,520 per surviving patient. LAmB was the preferred alternative by TL5,362 per successfully treated patient. Removing fever resolution as part of the composite outcome measure resulted in voriconazole being the preferred alternative per successfully treated patient. Univariate sensitivity analysis highlighted that increasing the duration of voriconazole by >1.2 days or decreasing LAmB by >1.0 days changes the result. Monte Carlo Simulation resulted in 69.4% of simulations favouring voriconazole per patient treated.

Conclusion

There is a strong likelihood that voriconazole is economically more favourable than LAmB in the empiric treatment of IFI in Turkey.

[Antifungal therapy update: new drugs and medical uses]

Increases in the rates of fungal infections, as well as their associated morbidity and mortality has led to a need for additional antifungal agents. The most common serious fungal agents in immunosuppressed and critically ill patients are Candida spp. and Aspergillus spp., although other emerging fungi must be considered. Rational, early systemic antifungal treatment should be based on diagnostic imaging techniques and conventional mycological and non-culture-based procedures. While the availability of new therapeutic options is an important advance, antifungal therapy has become increasingly complex. In addition to the available antifungal armamentarium, recent research has resulted in the introduction of three new antifungal agents: micafungin, anidulafungin, and posaconazole. This article provides an update, based on the latest scientific evidence, of the clinical efficacy, pharmacokinetics, safety and dosing of antifungal drugs administered in the management of Candida spp., Aspergillus spp., Cryptococcus spp., Zygomycetes, Scedosporium spp. and Fusarium spp.

Fungal infections: their diagnosis and treatment in transplant recipients

Systemic fungal infections typically occur in individuals who are seriously ill with recognized risk factors such as those frequently found in transplant recipients. Unfortunately, they are often diagnosed late, when the efficacy of the available treatments is low, often less than 50%, and the cost in terms of lives lost, hospital length of stay, and total hospital costs is substantially increased. The application of antifungal therapies associated with reported efficacy rates greater than 50% are those used prophylactically. When used prophylactically, these infections are reduced in greater than 95% of the expected cases. The choice of a prophylactic agent should be based upon its ease of administration, lack of adverse effects, reduced likelihood of potential drug interactions, and its efficacy in patients with established risk factors and comorbid disease processes that include renal, hepatic, and chronic pulmonary disease. The indications for the use of currently available antifungal agents, their adverse effects, drug interactions, ease of dosing, and applicability in patients with preexisting disease states, and especially in liver transplant recipients, are presented in this paper.

Characterization of the Candida parapsilosis complex in East China: species distribution differs among cities

Candida parapsilosis, which was previously considered to be a complex of three genetically distinct groups, has emerged as a significant agent of nosocomial infections. Recently, this complex was separated into three species: C. parapsilosis sensu stricto, C. orthopsilosis and C. metapsilosis. In China, data pertaining to these fungi are limited. In this study, we examined 57 isolates of members of the C. parapsilosis complex collected from four cities in East China, i.e., Nanjing (n = 22), Nanchang (n = 20), Shanghai (n = 12) and Jinan (n = 3). C. parapsilosis sensu stricto represented 71.9% of all isolates, while C. metapsilosis accounted for the remaining 28.1%. C. orthopsilosis could not be identified. A significantly high prevalence of C. metapsilosis was observed in strains recovered from Nanchang, 60% (12/20) of the isolates were C. metapsilosis. Sequence analysis of internal transcribed spacer region revealed two unevenly distributed genotypes among the C. metapsilosis strains. A PCR-restriction fragment length polymorphism assay was described for rapid identification. The strains were susceptible to fluconazole, voriconazole, amphoterincin B and micafungin. Six (15%) isolates of C. parapsilosis sensu stricto and three (18.8%) of C. metapsilosis were found to be dose-dependent susceptible to itraconazole. C. parapsilosis sensu stricto strains were less susceptible to micafungin than C. metapsilosis.

Anidulafungin: Review of its Role in the Treatment of Invasive Candidiasis

In 2006 a third echinocandin, anidulafungin, was approved in the USA for the treatment of candida esophagitis, candidemia, and invasive candida infections such as intra-abdominal abscesses and peritonitis in the non-neutropenic patient. Two years later it was approved in the EU for invasive candidiasis in non-neutropenic patients. Like other echinocandins, it is fungicidal against Candida species and fungistatic against Aspergillus species. It does not need adjustment for renal or hepatic insufficiency, and has no known drug interactions. Its administration is by the intravenous route only, and it is well tolerated. A steady state concentration can be achieved on day two by giving twice the maintenance dose on day one.

Anidulafungin for the treatment of invasive candidiasis

Candidaemia/invasive candidiasis (C/IC) is the most frequently occurring invasive fungal infection worldwide, with a particularly strong impact and high incidence in the intensive-care unit, where there is a need for new treatment options and strategies. The echinocandin anidulafungin has broad in vitro activity against a wide range of Candida species, along with favourable pharmacokinetics that allow administration in hepatic and renal impairment and with any comedication without the need for dose adjustments. The efficacy and safety of anidulafungin for the treatment of C/IC were demonstrated in a number of clinical studies and by some limited data from clinical practice. In a randomized comparative trial for the treatment of C/IC in adults, 76% of patients receiving anidulafungin and 60% of those given fluconazole were treated successfully (95% CI for difference: 4-27; p 0.01). Post hoc analyses suggest that anidulafungin is significantly more effective than standard-dose fluconazole for the treatment of candidaemia in critically ill patients. Anidulafungin is generally well tolerated, with commonly reported side effects including headache, hypokalaemia, gastrointestinal symptoms, abnormal liver function test results, and rash. In pharmaco-economic analyses, anidulafungin compared favourably with fluconazole (in terms of overall costs and hospital resource use) as well as with other echinocandins. Echinocandins, including anidulafungin, are now generally recommended as first-line therapy in moderately to severely ill patients, those with prior azole exposure, and patients with C/IC caused by Candida glabrata or Candida krusei.

[Drug interactions in critically-ill patients. An important factor in the use of micafungin?]

Currently there are three main drug groups for the prevention and treatment of fungal infections: polyenes (amphotericin B deoxycholate or its lipid formulations), azoles (fluconazole, itraconazole or posaconazole) and echinocandins (caspofungin, micafungin and anidulafungin). However, a major characteristic to be evaluated when choosing an antifungal agent -apart from antifungal spectrum, pharmacokinetics and adverse effects- is the absence of significant drug interactions. Amphotericin B lacks interactions but may cause renal dysfunction, leading to the accumulation of renally metabolized drugs. Nephrotoxicity is significantly lower with lipid formulations, especially with liposomal amphotericin B. Azoles modify the metabolism of a wide range of drugs by inhibiting their biotransformation or altering their distribution and elimination. These drugs are metabolized in the liver through the P450 cytochrome complex, inhibiting several isoenzymes, especially CYP3A4, the main drug-metabolizing enzyme. Moreover, itraconazole and posaconazole are substrates and inhibitors of the transporter protein, P-glycoprotein. Fluconazole is the azole with the fewest drug-drug interactions. The echinocandins have increased the therapeutic arsenal and a particular feature of these drugs is their safety, due to the absence of severe adverse effects and the scarce number of interactions. The echinocandin with the highest number of interactions is caspofungin. Micafungin is an echinocandin lacking in relevant interactions and consequently its dosage requires no adjustment in any of its indications. This drug can be used both in adults and in the pediatric population, including neonates.

Overview of treatment options for invasive fungal infections

The introduction of several new antifungals has significantly expanded both prophylaxis and treatment options for invasive fungal infections (IFIs). Relative to amphotericin B deoxycholate, lipid-based formulations of amphotericin B have significantly reduced the incidence of nephrotoxicity, but at a significant increase in drug acquisition cost. Newer, broad-spectrum triazoles (notably voriconazole and posaconazole) have added significantly to both the prevention and treatment of IFIs, most notably Aspergillus spp. (with voriconazole) and the treatment of some emerging fungal pathogens. Finally, a new class of parenteral antifungals, the echinocandins, is employed most frequently against invasive candidal infections. While the role of these newer agents continues to evolve, this review summarizes the activity, safety and clinical applications of agents most commonly employed in the treatment of IFIs.

Conclusions. Anidulafungin is a new echinocandin developed for more effective treatment of serious systemic fungal infections

Anidulafungin is a new echinocandin developed for more effective treatment of serious systemic fungal infections. Anidulafungin is a well tolerated echinocandin with a favorable pharmacokinetic profile; in particular, its lack of hepatic metabolism and renal excretion enables drug administration without dosage adjustment to subjects with any degree of impaired hepatic or renal function. This simplifies dosing, with a requirement for only once-daily administration and a lack of drug-drug interactions in patients who require multiple medications.

Echinocandins: The Newest Class of Antifungals

Objective:

To review the mechanism of action, antifungal spectrum of activity, pharmacodynamics, pharmacokinetics, clinical efficacy, and safety of the echinocandins.

Data Sources:

A MEDLINE search (1982–May 2009) was conducted for articles published in the English language using the key words caspofungin, micafungin, anidulafungin, and echinocandins.

Study Selection and Data Extraction:

Medicinal chemistry, in vitro, and animal studies, as well as human trials were reviewed for information on the pharmacodynamics, pharmacokinetics, efficacy, and safety of each echinocandin. Clinical trials were reviewed and included to compare and contrast the available echinocandins.

Data Synthesis:

Three echinocandin antifungal agents are currently approved for use in the US: caspofungin, micafungin, and anidulafungin. The echinocandins have a unique mechanism of action, inhibiting β-(1,3)-d-glucan synthase, an enzyme that is necessary for the synthesis of an essential component of the cell wall of several fungi. The echinocandins display fungistatic activity against Aspergillus spp. and fungicidal activity against most Candida spp., including strains that are fluconazole-resistant. The echinocandins have been shown to be efficacious for the treatment of esophageal candidiasis, candidemia, and invasive candidiasis. In addition, caspofungin has demonstrated efficacy as empiric treatment of febrile neutropenia and salvage therapy for the treatment of invasive aspergillosis, and it is the only echinocandin approved for use in pediatric patients. Micafungin is the only echinocandin approved for use as prophylaxis against Candida infections in patients undergoing hematopoietic stem cell transplantation. Overall, resistance to echinocandins is still rare, and all agents are well tolerated, with similar adverse effect profiles and few drug–drug interactions.

Conclusions:

Echinocandins, the newest addition to the arsenal of antifungals, offer potential advantages over other classes of agents. Clinicians should assess their distinguishing characteristics, including route of metabolism, drug interaction profile, and approved indications for use, when determining which agent to include on a formulary.

[Current treatment of candidemia. Role of anidulafungin]

Despite recent advances in antifungal therapy, the incidence of invasive Candida infections and resulting mortality have remained unchanged in the last few years. In surveillance studies published to date, the estimated incidence of candidemia differs depending on the geographic area and is significantly higher in North America than in Europe. The main predisposing conditions for candidemia are neutropenia, cellular immunity deficit, and alteration of normal microbial flora. Some independent risk factors have been identified, such as previous colonization, antibiotic therapy, central venous catheters, neutropenia, and renal dysfunction. In the last two decades, the proportion of infections due to non-albicans Candida has markedly increased. Although fluconazole use has been considered one of the main causes for the epidemiologic change in invasive candidiasis, especially in the increase of species less sensitive to this agent, this association remains unproven. These recent epidemiological changes are highly important when selecting treatment for candidemia. The echinocandins, which include anidulafungin, represent a step forward in the treatment of these infections. The clinical efficacy, tolerability and safety of anidulafungin have been demonstrated in controlled clinical trials in candidemia and invasive candidiasis. Current recommendations include this antifungal agent in the initial empirical therapy of certain patients, especially in those with a critical clinical situation, previous azole exposure, or the possibility of developing adverse events or drug interactions.

Pharmacotherapy of Candida Infections with Echinocandins

The classic recommended antifungal agents for the treatment of invasive Candida infections were amphotericin B, a lipid formulation of amphotericin B and fluconazole in both neutropenic or nonneutropenic patients as either primary or alternative therapies. Voriconazole has been recommended when additional coverage for filamentous fungi is needed (e.g. neutropenic patients). More recently and based on well designed comparative clinical trials, the three echinocandins, caspofungin, anidulafungin and micafungin have been added as primary or alternative therapies especially for critically ill or neutropenic patients. In general, the echinocandins are most useful when patients have previously been exposed to an azole or are unstable.

Anidulafungin: a novel echinocandin for candida infections

A third echinocandin, anidulafungin, has recently been approved for Candida infections in the non-neutropenic patient. In the EU it is indicated for invasive candidiasis; in 2006 it was approved in the USA for candida esophagitis, candidemia, and two types of invasive infections, peritonitis and intra-abdominal abscesses. It is fungicidal against Candida species and fungistatic against Aspergillus species. In addition to its favorable tolerability in studies to date, it does not need adjustment for renal or hepatic insufficiency and has no known drug interactions. A steady state concentration can be achieved on day 2 following a loading dose of twice the maintenance concentration on day 1, and the drug is administered intravenously once daily. Cross resistance with other classes of antifungals is not a concern as it possesses a unique mechanism of action.

Newer antifungal agents for invasive fungal infections in patients with haematological malignancy

Since 2001 five new systemically administered antifungal agents have been approved for clinical use. This represents a major advance for antifungal therapy in haematological malignancy patients undergoing chemotherapy or haematopoietic stem cell transplant (HSCT). The echinocandins are a new class of antifungals with a novel mode of action. Capsofungin has already established itself as a valuable therapy for candidaemia and salvage therapy of invasive aspergillosis. Although both anidulafungin and micafungin are approved for treatment of candidiasis, their role in invasive aspergillosis requires more clinical trial evaluation. Of the two newer triazoles, voriconazole has been recommended in international guidelines as primary therapy for acute invasive aspergillosis. Posaconazole has a broad spectrum of activity in vitro and a potentially key role in antifungal prophylaxis in high-risk HSCT recipients and during prolonged neutropenia. Although some of these drugs have important interactions with other medications, and potential toxicities, they are safer to use and more efficacious than amphotericin B deoxycholate. Their arrival gives more choices to treat rarer mycoses and will facilitate clinical trial assessment of combination therapy of aspergillosis where single agent therapy gives less than 50% success rates.

Candida parapsilosis, an emerging fungal pathogen

SUMMARY

Candida parapsilosis is an emerging major human pathogen that has dramatically increased in significance and prevalence over the past 2 decades, such that C. parapsilosis is now one of the leading causes of invasive candidal disease. Individuals at the highest risk for severe infection include neonates and patients in intensive care units. C. parapsilosis infections are especially associated with hyperalimentation solutions, prosthetic devices, and indwelling catheters, as well as the nosocomial spread of disease through the hands of health care workers. Factors involved in disease pathogenesis include the secretion of hydrolytic enzymes, adhesion to prosthetics, and biofilm formation. New molecular genetic tools are providing additional and much-needed information regarding C. parapsilosis virulence. The emerging information will provide a deeper understanding of C. parapsilosis pathogenesis and facilitate the development of new therapeutic approaches for treating C. parapsilosis infections.

[The role of anidulafungin therapy in solid organ transplant recipients]

Anidulafungin is a new echinocandin recently approved for the treatment of esophageal candidiasis, candidemia and other forms of invasive candidiasis, such as peritonitis and intra-abdominal abscesses in non-neutropenic patients. It is fungicidal against Candida spp. and fungistatic against Aspergillus spp. It is active against Pneumocystis jirovecii. In contrast, anidulafungin does not have activity against Cryptococcus neoformans, Zygomycetes or molds, other than Aspergillus spp. The drug is well tolerated, even in patients with renal or hepatic impairment. In contrast to other echinocandins, it does not significantly interfere with the cytochrome P450 pathway and has a low drug-drug interaction profile, including calcineurinic agents and other drugs used in transplant recipients. So far, anidulafungin appears to have an excellent safety profile with few adverse events and it promises a special consideration in the management of fungal infections happening in transplant recipients.