Efficacy and toxicity of intermediate-dose amphotericin B lipid complex as a primary or salvage treatment of fungal infections in patients with hematological malignancies

Recent Advances in Pharmaceutical Approaches of Antimicrobial Agents for Selective Delivery in Various Administration Routes

Globally, the increase of pathogenic bacteria with antibiotic-resistant characteristics has become a critical challenge in medical treatment. The misuse of conventional antibiotics to treat an infectious disease often results in increased resistance and a scarcity of effective antimicrobials to be used in the future against the organisms. Here, we discuss the rise of antimicrobial resistance (AMR) and the need to combat it through the discovery of new synthetic or naturally occurring antibacterial compounds, as well as insights into the application of various drug delivery approaches delivered via various routes compared to conventional delivery systems. AMR-related infectious diseases are also discussed, as is the efficiency of various delivery systems. Future considerations in developing highly effective antimicrobial delivery devices to address antibiotic resistance are also presented here, especially on the smart delivery system of antibiotics.

Antifungal Macrocycle Antibiotic Amphotericin B-Its Present and Future. Multidisciplinary Perspective for the Use in the Medical Practice

This review is devoted to a broad analysis of the results of studies of the effect of macrocyclic antifungal polyene antibiotic amphotericin B on cell membranes. A detailed study of polyenes has shown that some of them can have not only antifungal, but also antiviral and antitumor effects. Under conditions of global pandemic fungal pathology develops especially quickly and in this case leads to invasive aspergillosis, which contributes to the complication of coronavirus infection in the lungs and even secondary infection with invasive aspergillosis. The treatment of an invasive form of bronchopulmonary aspergillosis is directly related to the immunomodulatory and immunostimulating properties of the macrocyclic polyene drug amphotericin B. The article presents experimental data on the study of the biological activity and membrane properties of amphotericin B and the effect of its chemically modified derivatives, as well as liposomal forms of amphotericin B on viral, bacterial and fungal infections. The mechanism of action of amphotericin B and its analogues is based on their interaction with cellular and lipid membranes, followed by formation of ion channels of molecular size in the membranes. The importance of these studies is that polyenes are sensitive to membranes that contain sterols of a certain structure. The analysis showed that pathogenic fungal cells containing ergosterol were 10-100 times more sensitive to polyene antibiotics than host cell membranes containing cholesterol. The high sterol selectivity of the action of polyenes opens broad prospects for the use of polyene antifungal drugs in practical medicine and pharmacology in the treatment of invasive mycoses and the prevention of atherosclerosis. In this context, it should be noted that polyene antibiotics are the main tool in the study of the biochemical mechanism of changes in the permeability of cell membranes for energy-dependent substrates. Chemical and genetic engineering transformation of the structure of polyene antibiotic molecules opens prospects for the identification and creation of new biologically active forms of the antibiotic that have a high selectivity of action in the treatment of pathogenic infections.

[Antifungal macrocycle antibiotic amphotericin B - its present and future. Multidisciplinary perspective for the use in the medical practice]

This review is devoted to a broad analysis of the results of studies of the effect of macrocyclic antifungal polyene antibiotic amphotericin B on cell membranes. A multi-prolonged study of polyenes showed that some of them can have not only antifungal, but also antiviral and antitumor action. Fungal pathology develops especially quickly and in this case leads to invasive aspergillosis, which contributes to the complication of coronavirus infection in the lungs and even secondary infection with invasive aspergillosis in the context of a global pandemic. The treatment of an invasive form of bronchopulmonary aspergillosis is directly related to the immunomodulatory and immunostimulating properties of the macrocyclic polyene drug amphotericin B. The article presents experimental data on the study of the biological activity and membrane properties of amphotericin B and the effect of its chemically modified derivatives, as well as liposomal forms of amphotericin B on viral, bacterial and fungal infections. The mechanism of action of amphotericin B and its analogues is based on their interaction with cellular and lipid membranes, by forming ion channels of molecular size in them. The importance of these studies is that polyenes are sensitive to membranes that contain sterols of a certain structure. The analysis showed that pathogenic fungal cells containing ergosterol were 10-100 times more sensitive to polyene antibiotics than host cell membranes containing cholesterol. The high sterol selectivity of the action of polyenes opens up broad prospects for the use of polyene antifungal drugs in practical medicine and pharmacology in the treatment of invasive mycoses and the prevention of atherosclerosis. In this connection, it should be noted that polyene antibiotics are the main tool in the study of the biochemical mechanism of changes in the permeability of cell membranes for energy-dependent substrates. Chemical and genetic engineering transformation of the structure of polyene antibiotic molecules opens up prospects for the identification and creation of new biologically active forms of the antibiotic that have a high selectivity of action in the treatment of pathogenic infections.

Sixty years of Amphotericin B: An Overview of the Main Antifungal Agent Used to Treat Invasive Fungal Infections

Introduced in the late 1950s, polyenes represent the oldest family of antifungal drugs. The discovery of amphotericin B and its therapeutic uses is considered one of the most important scientific milestones of the twentieth century . Despite its toxic potential, it remains useful in the treatment of invasive fungal diseases owing to its broad spectrum of activity, low resistance rate, and excellent clinical and pharmacological action. The well-reported and defined toxicity of the conventional drug has meant that much attention has been paid to the development of new products that could minimize this effect. As a result, lipid-based formulations of amphotericin B have emerged and, even keeping the active principle in common, present distinct characteristics that may influence therapeutic results. This study presents an overview of the pharmacological properties of the different formulations for systemic use of amphotericin B available for the treatment of invasive fungal infections, highlighting the characteristics related to their chemical, pharmacokinetic structures, drug–target interactions, stability, and others, and points out the most relevant aspects for clinical practice.

Preclinical Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Antifungal Activity of Liposomal Amphotericin B

The improved safety profile and antifungal efficacy of liposomal amphotericin B (LAmB) compared to conventional amphotericin B deoxycholate (DAmB) is due to several factors including, its chemical composition, rigorous manufacturing standards, and ability to target and transit through the fungal cell wall. Numerous preclinical studies have shown that LAmB administered intravenously distributes to tissues frequently infected by fungi at levels above the minimum inhibitory concentration (MIC) for many fungi. These concentrations can be maintained from one day to a few weeks, depending upon the tissue. Tissue accumulation is dose-dependent with drug clearance occurring most rapidly from the brain and slowest from the liver and spleen. LAmB localizes in lung epithelial lining fluid, within liver and splenic macrophages and in kidney distal tubules. LAmB has been used successfully in therapeutic and prophylactic animal models to treat many different fungal pathogens, significantly increasing survival and reducing tissue fungal burden.

Low Rate of Invasive Fungal Infections During Induction and Consolidation Chemotherapy for Adults with De Novo Acute Myeloid Leukemia Without Anti-mold Prophylaxis: Single-Center 2002-2018 Empirical/Pre-emptive Approach

Broad-spectrum antifungal prophylaxis is currently considered the standard of care for adults with de novo AML for the prevention of invasive fungal infections (IFIs), especially invasive pulmonary aspergillosis (IPA). Because fluconazole has been used in our center as anti-yeast prophylaxis, we sought to analyze in detail the incidence of IFIs over a 17-year period, as well as their impact on outcome. A standardized protocol of patient management, including serum galactomannan screening and thoracic CT-guided diagnostic-driven antifungal therapy, was used in all patients. A total of 214 consecutive adults with de novo AML who were treated in 3 CETLAM (Grupo Cooperativo para el Estudio y Tratamiento de las Leucemias Agudas y Mielodisplasias) protocols from 2002 to 2018 were included. The 90-day incidence of any IFI (including possible cases) was 11% (95% CI 4-15%), most cases occurred during induction chemotherapy (8%, 95% CI 4-12%), and most cases were probable/proven IPA (8%, 95% CI 3-13%). Developing an IFI during induction and consolidation had no impact on 1-year survival. A case-control study with 23 cases of IPA and 69 controls identified induction/re-induction chemotherapy, chronic pulmonary disease and age > 60 years/poor baseline performance status as potential pretreatment risk factors. The current study proves that inpatient induction and consolidation chemotherapy for de novo AML can be given in areas with "a priori" high-burden of airborne molds with fluconazole prophylaxis, while the selective use of anti-mold prophylaxis in patients at very high risk may further reduce the incidence of IFI in this specific clinical scenario.

Treatment of invasive fungal diseases in cancer patients-Revised 2019 Recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

BACKGROUND

Invasive fungal diseases remain a major cause of morbidity and mortality in cancer patients undergoing intensive cytotoxic therapy. The choice of the most appropriate antifungal treatment (AFT) depends on the fungal species suspected or identified, the patient's risk factors (eg length and depth of granulocytopenia) and the expected side effects.

OBJECTIVES

Since the last edition of recommendations for 'Treatment of invasive fungal infections in cancer patients' of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO) in 2013, treatment strategies were gradually moving away from solely empirical therapy of presumed or possible invasive fungal diseases (IFDs) towards pre-emptive therapy of probable IFD.

METHODS

The guideline was prepared by German clinical experts for infections in cancer patients in a stepwise consensus process. MEDLINE was systematically searched for English-language publications from January 1975 up to September 2019 using the key terms such as 'invasive fungal infection' and/or 'invasive fungal disease' and at least one of the following: antifungal agents, cancer, haematological malignancy, antifungal therapy, neutropenia, granulocytopenia, mycoses, aspergillosis, candidosis and mucormycosis.

RESULTS

AFT of IFDs in cancer patients may include not only antifungal agents but also non-pharmacologic treatment. In addition, the armamentarium of antifungals for treatment of IFDs has been broadened (eg licensing of isavuconazole). Additional antifungals are currently under investigation or in clinical trials.

CONCLUSIONS

Here, updated recommendations for the treatment of proven or probable IFDs are given. All recommendations including the levels of evidence are summarised in tables to give the reader rapid access to key information.

Concurrent lung infections in patients with hematological malignancies and invasive pulmonary aspergillosis: how firm is the Aspergillus diagnosis?

BACKGROUND

Immunocompromised patients with hematological malignancies and/or recipients of hematopoietic stem cell transplants are constantly exposed to several fungal, bacterial, and viral respiratory pathogens.

METHODS

We retrospectively evaluated all patients with invasive pulmonary aspergillosis (IPA) and underlying hematological malignancies for the presence of concurrent, microbiologically documented pulmonary infections during a 5-year period (2005-2010).

RESULTS

We found 126 such patients that frequently had coinfections (49%) with respiratory pathogens other than Aspergillus species, with a higher rate in patients with probable IPA (53%) than in those with proven IPA (29%; P=0.038).

CONCLUSIONS

As the majority of patients with IPA in daily practice have probable IPA, often according to only the combination of positivity for serological biomarkers and radiological findings, our data may raise skepticism about both the certainty of IPA diagnosis and the evaluation of response to antifungals in a subset of these patients.

Amphotericin B lipid complex: treatment of invasive fungal infections in patients refractory to or intolerant of amphotericin B deoxycholate

Amphotericin B lipid complex (ABLC) was introduced in the late 1990s as a less toxic alternative to amphotericin B (AmB) deoxycholate. ABLC is a safe and effective broad-spectrum drug in the treatment of invasive fungal infections in patients with infection refractory to AmB deoxycholate or in patients intolerant of the same formulation. The drug has not been rigorously evaluated for primary therapy. Recent availability of several newer potent and safe drugs has sharply curtailed the use of potentially nephrotoxic ABLC. However, AmB lipid complex is likely to continue to play a limited albeit significant clinical role in view of the narrow spectrum of activity and significant drug-drug interactions of the newer drugs and emergence of drug-resistant fungi.

The current role of amphotericin B lipid complex in managing systemic fungal infections

BACKGROUND

An increase in the number of immunocompromised patients has led to a rising burden of systemic fungal infections. Historically, conventional amphotericin B has been used to treat these infections due to its broad spectrum of activity. The development of lipid-based amphotericin B agents, such as Abelcet * (ABLC), has allowed clinicians to take advantage of the broad spectrum of activity of amphotericin B while reducing adverse events. As well as this, a number of new antifungal agents have been developed in recent years which have significantly added to the treating physician's antifungal armamentarium. * Abelcet is a registered trade name of Cephalon Ltd, Herts, UK.

OBJECTIVES

Review the clinical data that support the use of ABLC and discuss the evidence for its continuing role in the treatment of invasive fungal infections in light of the introduction of newer antifungal agents.

METHODS

Published studies were identified by searching the MEDLINE database and the Cochrane Centre for Reviews up to August 2009. The search was conducted using the following key words: Amphotericin, Lipid, Abelcet, AmBisome, Efficacy, Nephrotoxicity, Renal, Toxicity.

FINDINGS

ABLC is effective and well-tolerated in the treatment of systemic fungal infections and remains a valuable therapeutic option in a variety of immunocompromised patients due to its broad antifungal spectrum and rarity of resistance.

LIMITATIONS

Data from randomised controlled trials of lipid-based amphotericin B formulations, as well as head-to-head comparison studies between ABLC and other antifungal agents are limited. In addition, the review uses a narrative approach and relies to a great extent on the authors' personal views and experiences.

Predicting survival in adults with invasive aspergillosis during therapy for hematological malignancies or after hematopoietic stem cell transplantation: Single-center analysis and validation of the Seattle, French, and Strasbourg prognostic indexes

In this retrospective monocenter study, we analyzed the outcomes of 130 adult hematological patients who developed a proven (n = 23), probable (n = 71), and possible (n = 36) invasive aspergillosis (IA) in a 13-year period. Forty-nine patients (38%) were recipients of an allogeneic hematopoietic stem cell transplantation (AlloHSCT). The main goal of the study was the identification of prognostic factors for 4-month aspergillosis free survival (AFS) and overall survival (OS). IA was identified as the main cause of death in 27/49 recipients of an AlloHSCT (55%) and 28/81 nontransplanted patients (35%). Diagnosis of IA at or before 2000 had a negative impact in both 4-month AFS and 4-month OS in the entire group. In multivariate analysis performed separately for nontransplanted and allo-HSCT patients, five variables (excluding the year of diagnosis) decreased 4-month AFS: (i) impairment of one organ function (OF), (ii) impairment of two or more OFs (two points), (iii) disseminated IA, (iv) neutropenia lasting more than 10 days (non-AlloHSCT group only) or monocytopenia (<0.1 x 10(9)/l) [AlloHSCT group only], and (v) high-dose steroids (non-AlloHSCT group only) or an alternative donor (AlloHSCT group only). According to the number of adverse risk factors, three prognostic subgroups were defined in non-transplanted and alloHSCT patients with good (97% and 78% AFS), intermediate (73% and 32% AFS) and poor prognosis (20% and 11% AFS) of IA [P < 0.01]. In addition, we validated the French and Seattle prognostic indexes for allo-HSCT recipients and the Strasbourg model for all hematological patients with IA.

Invasive aspergillosis: epidemiology, diagnosis and management in immunocompromised patients

Morbidity and mortality caused by invasive Aspergillus infections are increasing. This is because of the higher number of patients with malignancies treated with intensive immunosuppressive therapy regimens as well as their improved survival from formerly fatal bacterial infections, and the rising number of patients undergoing allogeneic haematopoietic stem cell or organ transplantation. Early initiation of effective systemic antifungal treatment is essential for a successful clinical outcome in these patients; however, clinical clues for diagnosis are sparse and early microbiological proof of invasive aspergillosis (IA) is rare. Clinical diagnosis is based on pulmonary CT scan findings and non-culture based diagnostic techniques such as galactomannan or DNA detection in blood or bronchoalveolar lavage samples. Most promising outcomes can be expected in patients at high risk for aspergillosis in whom antifungal treatment has been started pre-emptively, backed up by laboratory and imaging findings. The gold standard of systemic antifungal treatment is voriconazole, which has been proven to be significantly superior to conventional amphotericin B and has led to a profound improvement of survival rates in patients with cerebral aspergillosis. Liposomal amphotericin B at standard dosages appears to be a suitable alternative for primary treatment, while caspofungin, amphotericin B lipid complex or posaconazole have shown partial or complete response in patients who had been refractory to or intolerant of primary antifungal therapy. Combination therapy with two antifungal compounds may be a promising future strategy for first-line treatment. Lung resection helps to prevent fatal haemorrhage in single patients with pulmonary lesions located in close proximity to larger blood vessels, but is primarily considered for reducing the risk of relapse during subsequent periods of severe immunosuppression. Strict reverse isolation appears to reduce the incidence of aspergillosis in allogeneic stem cell transplant recipients and patients with acute myeloid leukaemia undergoing aggressive anticancer therapy. Well designed, prospective randomised studies on infection control measures effective to prevent aspergillosis are lacking. Prophylactic systemic antifungal treatment with posaconazole significantly improves survival and reduces IA in acute myeloid leukaemia patients and reduces aspergillosis incidence rates in patients with intermediate-to-severe graft-versus-host reaction emerging after allogeneic haematopoietic stem cell transplantation. Voriconazole prophylaxis may be suitable for prevention of IA as well; however, the results of large clinical trials are still awaited.

Nosocomial fungal infections: epidemiology, diagnosis, and treatment

Invasive fungal infections are increasingly common in the nosocomial setting. Furthermore, because risk factors for these infections continue to increase in frequency, it is likely that nosocomial fungal infections will continue to increase in frequency in the coming decades. The predominant nosocomial fungal pathogens include Candida spp., Aspergillus spp., Mucorales, Fusarium spp., and other molds, including Scedosporium spp. These infections are difficult to diagnose and cause high morbidity and mortality despite antifungal therapy. Early initiation of effective antifungal therapy and reversal of underlying host defects remain the cornerstones of treatment for nosocomial fungal infections. In recent years, new antifungal agents have become available, resulting in a change in standard of care for many of these infections. Nevertheless, the mortality of nosocomial fungal infections remains high, and new therapeutic and preventative strategies are needed.

Is there a role for polyenes in treating invasive mycoses?

PURPOSE OF REVIEW

This is a clinical review on the current role of polyene antifungals in the treatment of invasive fungal infections. It is timely and relevant because the number of new antifungals being developed has never been greater than today. In addition to re-examining the landmark clinical trials of the past, the more recent findings are put into perspective. The past year has been particularly rich in clinical trials.

RECENT FINDINGS

The main topics of this review are invasive candidiasis, invasive aspergillosis, and the so-called rare fungal infections: zygomycosis, fusariosis, cryptococcosis and histoplasmosis.

SUMMARY

Practical implications of the recent developments are the almost complete replacement of amphotericin B deoxycholate by lipid-based formulations; antifungal efficacy without compromising safety; and treatment choices for infections previously considered untreatable.