Echinocandins in the treatment of candidaemia and invasive candidiasis: clinical and economic perspectives

Health-economic modelling of cost savings due to the use of rezafungin based on a German cost-of-illness study of candidiasis

Objective

Candida species are responsible for fungal diseases and the development of nosocomial bloodstream infections. Treatment is resource-intensive and economically challenging for healthcare systems. Cost analyses of drugs against candidiasis, such as rezafungin, are thus of great interest to healthcare payers.

Methods

We conducted a cost-of-illness study of patients with Candida infections based on real-word data of the Department I of Internal Medicine, University Hospital Cologne (Germany) between 2016 and 2021. Health-economic parameters were analysed to describe the economic impact of Candida infections. Potential cost savings due to the administration of rezafungin were modelled for patients with invasive candidiasis or candidaemia based on a 5 day reduction of ICU length of stay (LOS) shown by the STRIVE study.

Results

We found 724 cases (652 patients) with Candida infections, of which 61% received ICU treatment (n = 442) and 29% were mechanically ventilated (n = 207). Twenty-six percent died during hospitalization (n = 185). Median LOS was 25 and 15 days, on normal wards and ICU, respectively. Median total treatment costs per case accounted for €22 820. Based on the ICU LOS reduction, the retrospective model showed a median cost-saving potential of €7175 per hospital case with invasive candidiasis or candidaemia. Accumulated cost savings for 37 patients of €283 335 were found.

Conclusions

Treatment of candidiasis is cost intensive due to increased hospital LOS. The ICU LOS reduction rezafungin showed in STRIVE would lead to sustainable cost savings.

Invasive candidiasis: current clinical challenges and unmet needs in adult populations

Invasive candidiasis (IC) is a serious infection caused by several Candida species, and the most common fungal disease in hospitals in high-income countries. Despite overall improvements in health systems and ICU care in the last few decades, as well as the development of different antifungals and microbiological techniques, mortality rates in IC have not substantially improved. The aim of this review is to summarize the main issues underlying the management of adults affected by IC, focusing on specific forms of the infection: IC developed by ICU patients, IC observed in haematological patients, breakthrough candidaemia, sanctuary site candidiasis, intra-abdominal infections and other challenging infections. Several key challenges need to be tackled to improve the clinical management and outcomes of IC patients. These include the lack of global epidemiological data for IC, the limitations of the diagnostic tests and risk scoring tools currently available, the absence of standardized effectiveness outcomes and long-term data for IC, the timing for the initiation of antifungal therapy and the limited recommendations on the optimal step-down therapy from echinocandins to azoles or the total duration of therapy. The availability of new compounds may overcome some of the challenges identified and increase the existing options for management of chronic Candida infections and ambulant patient treatments. However, early identification of patients that require antifungal therapy and treatment of sanctuary site infections remain a challenge and will require further innovations.

Antifungal prescription practices and consumption in a tertiary care hospital of a developing country

BACKGROUND

Antifungal stewardship is a less explored component of antimicrobial stewardship programmes, especially in developing countries.

OBJECTIVE

We aimed to determine antifungal prescription practices in a tertiary centre of a developing country to identify the challenges for antifungal stewardship programmes.

METHODS

Four single-day point prevalent surveys were performed in inpatient units and data were collected from medical records. Antifungal use was recorded in terms of consumption, therapeutic strategies and appropriateness.

RESULTS

We found a 2.42%-point prevalence of antifungal prescriptions. Antifungal use was higher in children than adults (4.1% vs. 2.03%), medical than surgical units (3.7% vs. 1.24%) and ICUs than general wards (5.8% vs. 1.9%). The highest antifungal use was observed in the haematology-oncology units (29.3%) followed by emergency (16.2%) and gastroenterology units (11.6%). Among 215 prescriptions, amphotericin B was the most commonly prescribed (50.2%) followed by fluconazole (31.6%). The targeted antifungal therapy was practised more commonly (31.5%) than empiric (29.1%), pre-emptive (22.6%) and prophylactic (16.8%) therapy. Amphotericin B was commonly used for pre-emptive (p = .001) and targeted (p = .049) therapy, while fluconazole (p = .001) and voriconazole (p = .011) for prophylaxis. The prescriptions were inappropriate in 25.1% due to the wrong choice of antifungal (44.4%), indication (27.7%) and dosage (24%). The overall mean antifungal consumption was 2.71 DDD/1000 PD and 8.96 DOT/1000 PD.

CONCLUSIONS

We report here the low prevalence of antifungal use at a tertiary care centre in a developing country. Though training for antifungal use would be important for antifungal stewardship, the challenge would remain with the affordability of antifungals.

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.

Functional expression of an echinocandin B deacylase from Actinoplanes utahensis in Escherichia coli

Echinocandin B deacylase (ECBD) from Actinoplanes utahensis can be applied to produce echinocandin B nucleus (ECBN), an essential intermediate of the echinocandins antifungal drugs such as anidulafungin. To date, the expression of ECBD has been limited to Streptomyces. To achieve the active expression of ECBD in Escherichia coli (E. coli), we constructed a plasmid carrying two subunits of ECBD for T7 RNA polymerase driven transcription of dicistron messenger after codon optimization. Subsequently, the introduction of peptide tags in the recombinant ECBD was adopted to reduce the formation of inclusion bodies and enhance the ECBD solubility. The peptide tags with the opposite electrostatic charge, hexa-lysine (6K) and GEGEG (GE), exhibited the best positive effect, which was verified by activity assay and structural simulation. After that, optimization of culture conditions and characterization of ECBD were conducted, the optimal pH and temperature were 7.0 and 60 °C. It is the first report concerning the functional expression of ECBD in the host E. coli. Our results reported here can provide a reference for the high-level expression of other deacylases with respect to a possible industrial application.

Economic evaluation of micafungin versus liposomal amphotericin B (LAmB) for treating patients with candidaemia and invasive candidiasis (IC) in Turkey

Micafungin was reported to be non-inferior to liposomal amphotericin B (LAmB) in treating patients with candidaemia and invasive candidiasis (IC). The current study aimed to evaluate the economic impact of using micafungin versus LAmB for treatment of candidaemia and IC in Turkey. A decision analytic model, which depicted economic consequences upon administration of micafungin or LAmB for treating patients with candidaemia and IC in the Turkish hospitals, was constructed. Patients were switched to an alternative antifungal agent if initial treatment failed due to mycological persistence. All patients were followed up until treatment success or death. Outcome probabilities were obtained from published literature and cost inputs were derived from the latest Turkish resources. Expert panels were used to estimate data that were not available in the literature. Cost per patient treated for each intervention was then calculated. Sensitivity analyses including Monte Carlo simulation were performed. For treatment of candidaemia and IC, micafungin (€4809) was associated with higher total cost than LAmB (€4467), with an additional cost of €341 per treated patient. Cost of initial antifungal treatment was the major cost driver for both comparators. The model outcome was robust over a wide variation in input variables except for drug acquisition cost and duration of initial antifungal treatment with micafungin or LAmB. LAmB is cost-saving relative to micafungin for the treatment of candidaemia and IC from the Turkish hospital perspective, with variation in drug acquisition cost of the critical factor affecting the model outcome.

Pharmacoeconomic evaluation of micafungin versus caspofungin as definitive therapy for candidaemia and invasive candidiasis (IC) in Turkey

Micafungin was shown to be as efficacious as caspofungin in treating patients with candidaemia and invasive candidiasis (IC). However, it remains unknown if micafungin or caspofungin is a cost-effective definitive therapy for candidaemia and IC in Turkey. The present study aimed to determine the economic impact of using micafungin versus caspofungin for treatment of candidaemia and IC in the Turkish setting. A decision analytic model was constructed and was populated with data (i.e. transition probabilities, duration of initial antifungal treatment, reasons for treatment failure, percentage of patients who stepped down to oral fluconazole, and duration on oral fluconazole) obtained from a published randomised clinical trial. Cost inputs were derived from the latest Turkish resources while data that were not readily available in the literature were estimated by expert panels. One-way sensitivity analyses, threshold analyses, scenario analyses and probabilistic sensitivity analyses were conducted. Caspofungin (€2693) incurred a lower total cost than micafungin (€4422), with a net cost saving of €1729 per treated patient. Drug acquisition cost was the main cost driver for both study arms. The model outcome was robust over wide variations (of ±100.0% from the base case value) for all input parameters except for micafungin drug cost and the duration of initial treatment with micafungin. Caspofungin appears to be a cost-saving option in treating candidaemia and IC from the Turkish hospital perspective.

Cost-effectiveness analysis of anidulafungin vs fluconazole for the treatment of invasive candidiasis (IC) in Turkey

Anidulafungin has been shown to be non-inferior to, and possibly more efficacious, than fluconazole in treating patients with invasive candidiasis (IC). This study aimed to determine the cost-effectiveness of anidulafungin vs fluconazole for treatment of IC in the Turkish setting. A decision analytic model was constructed to depict downstream economic consequences of using anidulafungin or fluconazole for treatment of IC in the Turkish hospitals. Transition probabilities (ie treatment success, observed or indeterminate treatment failures) were obtained from a published randomised clinical trial. Cost inputs were from the latest Turkish resources. Data not available in the literature were estimated by expert panels. Sensitivity analyses were performed to assess the robustness of the model outcome. While anidulafungin [TL 17 171 (USD 4589)] incurred a higher total cost than fluconazole [TL 8233 (USD 2200) per treated patient, treatment with anidulafungin was estimated to save an additional 0.58 life-years, with an incremental cost-effectiveness ratio of TL 15 410 (USD 4118) per life-years saved. Drug acquisition cost and hospitalisation were the main cost drivers for anidulafungin and fluconazole arms respectively. The model findings were robust over a wide range of input variables except for anidulafungin drug cost. Anidulafungin appears to be a cost-effective therapy in treating IC from the Turkish hospital perspective.

The Surgical Infection Society Revised Guidelines on the Management of Intra-Abdominal Infection

BACKGROUND

Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.

METHODS

Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.

RESULTS

This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.

SUMMARY

The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline.

A Risk Score for Fluconazole Failure among Patients with Candidemia

This study aimed to develop a prediction model to identify patients with candidemia who were at high risk of failing fluconazole treatment. Adult patients in the United States with candidemia who received fluconazole during hospitalization were selected from the Cerner Health Facts Hospital Database (04/2004 to 03/2013). Fluconazole failure was defined as switching/adding another antifungal, positive Candida culture ≥10 days after fluconazole initiation, or death during hospitalization. Patients were randomized into modeling and validation samples. Using the modeling sample, a regression analysis of least absolute shrinkage and selection operator was used to select risk predictors of fluconazole failure (demographics, Candida species, initiation of fluconazole before positive culture and after admission, and comorbidities, procedures, and treatments during the 6 months before admission and fluconazole initiation). The prediction model was evaluated using the validation sample. We found that of 987 identified patients (average age of 61 years, 51% male, 72% Caucasian), 49% failed and 51% did not fail fluconazole treatment. Of those who failed, 70% switched or added another antifungal, 21% had a second positive Candida test, and 42% died during hospitalization. Nine risk factors were included in the prediction model: days to start fluconazole after admission, Candida glabrata or Candida krusei infection, hematological malignancy, venous thromboembolism (VTE), enteral nutrition, use of nonoperative intubation/irrigation, and other antifungal use. All but VTE were associated with a higher risk of failure. The model's c-statistic was 0.65, with a Hosmer-Lemeshow test P value of 0.23. In summary, this prediction model identified patients with a high risk of fluconazole failure, illustrating the potential value and feasibility of personalizing candidemia treatment.

(1,3)-β-d-Glucan-based antifungal treatment in critically ill adults at high risk of candidaemia: an observational study

OBJECTIVES

To determine the effects of a strategy that uses serum (1,3)-β-d-glucan (BDG) results for antifungal treatment of ICU patients at high risk of invasive candidiasis.

PATIENTS AND METHODS

Adult patients admitted to the ICU from January 2012 to June 2014 were included if they exhibited sepsis at the time of BDG testing and they met Candida score components ≥3. A retrospective analysis of collected data was performed.

RESULTS

In total, 198 patients were studied. Of 63 BDG-positive patients, 47 with candidaemia and 16 with probable Candida infection, all [31.8% (63/198)] received antifungal therapy. Of 135 BDG-negative patients, 110 [55.5% (110/198)] did not receive antifungal therapy, whereas 25 [12.6% (25/198)] were initially treated. Overall, antifungal therapy was started in 88 cases (44.4%), mostly with echinocandins. Antifungals were discontinued in 14 of 25 patients, as negative BDG results became available, and in 16 BDG-false-positive patients for whom subsequent findings allowed candidaemia (and other forms of invasive candidiasis) to be ruled out. Candidaemia was diagnosed only in one patient who did not receive prior antifungal therapy. The median antifungal therapy duration in candidaemic patients differed significantly from that in non-candidaemic patients [14 (IQR, 6-18) days versus 4 (IQR, 3-7) days; P < 0.001]. Using this approach, antifungal therapy was avoided in ∼73% of potentially treatable patients and it was shortened in another ∼20%.

CONCLUSIONS

This study supports the use of serum BDG results in the management of systemic antifungal drug prescription in septic patients. These findings need to be confirmed in additional studies.

Antifungal drug resistance among Candida species: mechanisms and clinical impact

The epidemiology of Candida infections has changed in recent years. Although Candida albicans is still the main cause of invasive candidiasis in most clinical settings, a substantial proportion of patients is now infected with non-albicans Candida species. The various Candida species vary in their susceptibility to the most commonly used antifungal agents, and the intrinsic resistance to antifungal therapy seen in some species, along with the development of acquired resistance during treatment in others, is becoming a major problem in the management of Candida infection. A better understanding of the mechanisms and clinical impact of antifungal drug resistance is essential for the efficient treatment of patients with Candida infection and for improving treatment outcomes. Herein, we report resistance to the azoles and echinocandins among Candida species.

Whole animal HTS of small molecules for antifungal compounds

INTRODUCTION

The high morbidity and mortality among patients with invasive fungal infections and the growing problem of fungal resistance have resulted in an urgent need for new antifungal agents.

AREAS COVERED

This review covers the importance of antifungal drug discovery with an emphasis on whole-animal high-throughput techniques. More specifically, the authors focus on Caenorhabditis elegans, as a substitute model host and discuss C. elegans as an alternative model host for the study of microbial pathogenesis and the identification of novel antifungal compounds.

EXPERT OPINION

There are significant advantages from using the substitute model host C. elegans in high-throughput drug discovery. The C. elegans-microbe model provides a whole animal system where host-pathogen interactions can be studied along with the evaluation of antimicrobial efficacy of compounds. This approach allows the study of compound characteristics, such as toxicity and solubility, during the initial screen and compounds discovered using C. elegans are affective in mammalian models.

Consumption of systemic antifungal agents among acute care hospitals in Catalonia (Spain), 2008-2013

Objective To know the patterns and consumption trends (2008-2013) of antifungal agents for systemic use in 52 acute care hospitals affiliated to VINCat Program in Catalonia (Spain). Methods Consumption was calculated in defined daily doses (DDD)/100 patient-days and analyzed according to hospital size and complexity and clinical departments. Results Antifungal consumption was higher in intensive care units (ICU) (14.79) than in medical (3.08) and surgical departments (1.19). Fluconazole was the most consumed agent in all type of hospitals and departments. Overall antifungal consumption increased by 20.5%during the study period (p = 0.066); a significant upward trend was observed in the consumption of both azoles and echinocandins. In ICUs, antifungal consumption increased by 12.4% (p = 0.019). Conclusions The study showed a sustained increase in the overall consumption of systemic antifungals in a large number of acute care hospitals of different characteristics in Catalonia. In ICUs there was a trend towards the substitution of older agents by the new ones.

Design and studies of multiple mechanism of anti-Candida activity of a new potent Trp-rich peptide dendrimers

PURPOSE

Eight peptide dendrimers were designed as structural mimics of natural cationic amphiphilic peptides with antifungal activity and evaluated for their anti-Candida potential against the wild type strains and mutants.

METHODS

Dendrimer 14 containing four Trp residues and dodecyl tail and a slightly smaller dendrimer 9 decorated with four N-methylated Trp that displayed 100 and 99.7% of growth inhibition at 16 μg/mL respectively, were selected for evaluation against the Candida albicans mutants with disabled biosynthesis of aspartic proteases responsible for host tissue colonization and morphogenesis during biofilm formation (sessile model). Flow cytometry method was employed to detect apoptotic cells with membrane alterations (phosphatidylserine translocation), and differentiation of apoptotic from necrotic cells was also performed. Simultaneous staining of cell surface phosphatidylserine with Annexin-V-Fluorescein and necrotic cells with propidium iodide was conducted.

RESULTS

14 at 16 μg/mL caused C. albicans cells to undergo cellular apoptosis but its increasing concentrations induced necrosis. 14 influenced C. albicans biofilm viability as well as hyphal and cell wall morphology. Confocal microscopy and cell wall staining with calcofluor white revealed that in epithelial model the cell surface structure was perturbed at MIC of peptide dendrimer. It appears that tryptophan or 1-methyltryptophan groups displayed at the surface and positive charges hidden in the dendrimer tree along with hydrocarbon tail located at C-terminus are important for the anti-Candida activity since dendrimers containing tryptamine at C-terminus showed only a moderate activity.

CONCLUSIONS

Our results suggest that membranolytic dendrimer 14, targeting cellular apoptotic pathway and impairing the cell wall formation in mature biofilm, may be a potential multifunctional antifungal lead compound for the control of C. albicans infections.

Potential Targets for Antifungal Drug Discovery Based on Growth and Virulence in Candida albicans

Fungal infections, especially infections caused by Candida albicans, remain a challenging problem in clinical settings. Despite the development of more-effective antifungal drugs, their application is limited for various reasons. Thus, alternative treatments with drugs aimed at novel targets in C. albicans are needed. Knowledge of growth and virulence in fungal cells is essential not only to understand their pathogenic mechanisms but also to identify potential antifungal targets. This article reviews the current knowledge of the mechanisms of growth and virulence in C. albicans and examines potential targets for the development of new antifungal drugs.

Is Fluconazole or an Echinocandin the Agent of Choice for Candidemia

OBJECTIVE

Candidemia is among the most common nosocomial bloodstream infections and is associated with high mortality, increased length of hospital stay, and significant economic burden. The introduction of the echinocandins in the 2000s has expanded the armamentarium against Candida spp and provides therapeutic options that are effective, safe, and tolerable. Although the Infectious Diseases Society of America favors echinocandins as treatment for candidemia in selected settings (at least as initial therapy), there remain divergent opinions about whether an echinocandin or fluconazole is the preferred agent for candidemia, and clinical practice guidelines are in flux. In this review, the currently available laboratory and clinical data are summarized and critically evaluated.

DATA SOURCES

A MEDLINE search of the English language literature was performed using the search terms echinocandin, fluconazole, and candidemia. References of review articles and guidelines were also screened for inclusion.

STUDY SELECTION AND DATA EXTRACTION

Studies whose primary goal was to compare echinocandins with fluconazole were evaluated as well as studies that differentiated pharmacological and pharmacokinetic properties between agents.

DATA SYNTHESIS

It is clear that echinocandins and fluconazole each have roles in the management of candidemia. Specific recommendations are provided that will hopefully optimize outcomes in candidemia while incorporating stewardship concepts of cost-effectiveness and limiting the emergence of resistance.

CONCLUSIONS

Despite the advantages brought by the echinocandins and fluconazole, outcomes among patients with candidemia remain suboptimal. Improved treatment of candidemia may ultimately be achieved by optimizing the use of antifungal agents rather than the development of new drugs.