Safety, Tolerability, and Pharmacokinetics of Liposomal Amphotericin B in Immunocompromised Pediatric Patients

Development and in vitro evaluation of an infant friendly self-nanoemulsifying drug delivery system (SNEDDS) loaded with an amphotericin B-monoacyl phosphatidylcholine complex for oral delivery

Until relatively recently, the pediatric population has largely been ignored during the development of new drug products, which has led to a high level of "off-label" use of drugs in this particular population. In this study, an infant friendly self-nanoemulsifying drug delivery system (SNEDDS) was developed for oral delivery of a commonly used "off-label" drug - amphotericin B (AmB). AmB was complexed with monoacyl-phosphatidylcholine (MAPC) by lyophilization, transforming crystalline AmB into its amorphous state in the AmB-MAPC complex (APC). The APC-loaded SNEDDS (APC-SNEDDS) showed excellent self-emulsifying properties; after dispersion of the APC-SNEDDS in purified water, nanoscale emulsion droplets were formed within 1 min with a z-average size of 179 ± 1 nm. In vitro pediatric gastrointestinal (GI) digestion and dissolution results showed that the APC-SNEDDS significantly increased the amount of AmB solubilized in aqueous phase and that the precipitated AmB from the APC-SNEDDS re-dissolved faster, compared with crystalline AmB in SNEDDS (AmB-SNEDDS), the complex without the SNEDDS (APC), the physical mixture of AmB and MAPC (AmB/MAPC PM), and crystalline AmB alone (AmB). Overall, the present in vitro results suggest that integrating the APC into an infant friendly SNEDDS is a promising approach for oral delivery of AmB to young pediatric patients.

Therapeutic drug monitoring of liposomal amphotericin B in children. Are we there yet? A systematic review

INTRODUCTION

Therapeutic drug monitoring (TDM) is a tool that supports personalized dosing, but its role for liposomal amphotericin B (L-amb) is unclear. This systematic review assessed the evidence for L-amb TDM in children.

OBJECTIVES

To evaluate the concentration-efficacy relationship, concentration-toxicity relationship and pharmacokinetic/pharmacodynamic (PK/PD) variability of L-amb in children.

METHODS

We systematically reviewed PubMed and Embase databases following PRISMA guidelines. Eligible studies included L-amb PK/PD studies in children aged 0-18 years. Review articles, case series of

RESULTS

In total, 4220 studies were screened; 6 were included, presenting data on 195 children. Invasive candidiasis and aspergillosis were the two most common infections treated with L-amb. Studies showed significant PK variability due to age (mean age ranged from 14 days to 17 years), body weight, non-linear PK and changes in the volume of distribution. Limited evidence supported a peak concentration/MIC (Cmax/MIC) of 25-50 for optimal efficacy and an AUC24 of >600 mg·h/L for nephrotoxicity. L-amb doses of 2.5-10 mg/kg/day were reported to achieve Cmax/MIC > 25 using an MIC of 1 mg/L.

CONCLUSIONS

While significant PK variability was observed in children, evidence to support routine L-amb TDM was limited. Further studies on efficacy and toxicity benefits are required before routine TDM of L-amb can be recommended.

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Key Words Collapse

MESH Headings

• Humans
• Amphotericin B/pharmacokinetics
• Amphotericin B/administration & dosage
• Amphotericin B/adverse effects
• Amphotericin B/therapeutic use
• Drug Monitoring
• Child
• Antifungal Agents/pharmacokinetics
• Antifungal Agents/administration & dosage
• Antifungal Agents/adverse effects
• Antifungal Agents/therapeutic use
• Child, Preschool
• Adolescent
• Infant
• Infant, Newborn
• Aspergillosis/drug therapy
• Microbial Sensitivity Tests

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Grants

• Australian Government (RTP) Scholarship

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Affiliation(s)

Tony Lai Pharmacy Department, The Children’s Hospital at Westmead, Sydney, NSW, Australia The University of Sydney Infectious Diseases Institute (Sydney ID), Sydney, NSW, Australia Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
Chin-Yen Yeo Pharmacy Department, Concord Hospital, Sydney, Australia
Bradley Rockliff Pharmacy Department, The Children’s Hospital at Westmead, Sydney, NSW, Australia
Michael Stokes Pharmacy Department, The Children’s Hospital at Westmead, Sydney, NSW, Australia The University of Sydney Infectious Diseases Institute (Sydney ID), Sydney, NSW, Australia
Hannah Yejin Kim Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia Pharmacy Department, Westmead Hospital, Sydney, Australia
Ben J Marais The University of Sydney Infectious Diseases Institute (Sydney ID), Sydney, NSW, Australia
Andrew J McLachlan Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
Jan-Willem C Alffenaar The University of Sydney Infectious Diseases Institute (Sydney ID), Sydney, NSW, Australia Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia Pharmacy Department, Westmead Hospital, Sydney, Australia

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AmBisome® Formulations for Pediatrics: Stability, Cytotoxicity, and Cost-Effectiveness Studies

Liposomal amphotericin B (Ambisome®) is the gold standard for the treatment and prevention of fungal infections both in the adult and pediatric populations. The lyophilized dosage form has to be reconstituted and diluted by hospital staff, but its management can be challenging due to the spontaneous tendency of amphotericin B to form aggregates with different biological activity. In this study, the colloidal stability of the liposomes and the chemical stability of amphotericin B were investigated over time at storage conditions. Three liposomal formulations of amphotericin B at 4.0 mg/mL, 2.0 mg/mL, and 0.2 mg/mL were prepared and assayed for changes regarding the dimensional distribution, zeta potential, drug aggregation state, and onset of by-products. Our analyses highlighted that the most diluted formulation, kept at room temperature, showed the greatest changes in the aggregation state of the drug and accordingly the highest cytotoxicity. These findings are clinically relevant since the lower dosages are addressed to the more vulnerable patients. Therefore, the centralization of the dilution of AmBisome® at the pharmacy is of fundamental importance for assuring patient safety, and at the same time for reducing medication waste, as we demonstrated using the cost-saving analysis of drug expense per therapy carried out at the G. Gaslini children hospital.

Current Status of Pharmacokinetic Research in Children: A Systematic Review of Clinical Trial Records

BACKGROUND

Many medications have different pharmacokinetics in children than in adults. Knowledge about the safety and efficacy of medications in children requires research into the pharmacokinetic profiles of children's medicines. By analysing registered clinical trial records, this study determined how frequently pharmacokinetic data is gathered in paediatric drug trials.

METHODS

We searched for the pharmacokinetic data from clinical trial records for preterm infants and children up to the age of 16 from January 2011 to April 2022. The records of trials involving one or more drugs in preterm infants and children up to the age of 16 were examined for evidence that pharmacokinetic data would be collected.

RESULTS

In a total of 1483 records of interventional clinical trials, 136 (9.17%) pharmacokinetic data involved adults. Of those 136 records, 60 (44.1%) records were pharmacokinetics trials involving one or more medicines in children up to the age of 16. 20 (33.3 %) in America, followed by 19 (31.6 %) in Europe. Most trials researched medicines in the field of infection or parasitic diseases 20 (33.3%). 27 (48.2%) and 26 (46.4%) trials investigated medicines that were indicated as essential medicine.

CONCLUSION

The pharmacokinetic characteristics of children's drugs need to be better understood. The current state of pharmacokinetic research appears to address the knowledge gap in this area adequately. Despite slow progress, paediatric clinical trials have experienced a renaissance as the significance of paediatric trials has gained international attention. The outcome of paediatric trials will have an impact on children's health in the future. In recent years, the need for greater availability and access to safe child-size pharmaceuticals has received a lot of attention.

Liposomal amphotericin B-the present

Most invasive fungal infections are opportunistic in nature but the epidemiology is constantly changing, with new risk groups being identified. Neutropenia is a classical risk factor for fungal infections, while critically ill patients in the ICU are now increasingly at risk of yeast and mould infections. Factors to be considered when choosing antifungal treatment include the emergence of rarer fungal pathogens, the risk of resistance to azoles and echinocandins and the possibility of drug-drug interactions. Liposomal amphotericin B has retained its place in the therapeutic armamentarium based on its clinical profile: a broad spectrum of antifungal activity with a low risk of resistance, predictable pharmacokinetics with a rapid accumulation at the infection site (including biofilms), a low potential for drug-drug interactions and a low risk of acute and chronic treatment-limiting toxicities versus other formulations of amphotericin B. It is a suitable choice for the first-line empirical or pre-emptive treatment of suspected fungal infections in neutropenic haematology patients and is an excellent alternative for patients with documented fungal disease who can no longer tolerate or continue their first-line azole or echinocandin therapy, both in the haematology setting and in the ICU. Moreover, it is the first-line drug of choice for the treatment of invasive mucormycosis. Finally, liposomal amphotericin B is one of the few antifungal agents approved for use in children of all ages over 1 month and is included in paediatric-specific guidelines for the management of fungal disease.

Liposomal amphotericin B-the past

The discovery of amphotericin B, a polyene antifungal compound, in the 1950s, and the formulation of this compound in a liposomal drug delivery system, has resulted in decades of use in systemic fungal infections. The use of liposomal amphotericin B formulation is referenced in many international guidelines for the treatment of fungal infections such as Aspergillus and cryptococcal disease and Candida infections, as well as other less common infections such as visceral leishmaniasis. With the development of liposomal amphotericin B, an improved therapeutic index could be achieved that allowed the attainment of higher drug concentrations in both the plasma and tissue while simultaneously lowering the toxicity compared with amphotericin B deoxycholate. In over 30 years of experience with this drug, a vast amount of information has been collected on preclinical and clinical efficacy against a wide variety of pathogens, as well as evidence on its toxicity. This article explores the history and nature of the liposomal formulation, the key clinical studies that developed the pharmacokinetic, safety and efficacy profile of the liposomal formulation, and the available microbiological data.

Silver Chitosan Nanocomposites are Effective to Combat Sporotrichosis

The use of silver nanoparticles (AgNPs) embedded in polymeric matrix has acquired special attention as a strategy to reduce metal toxicity without losing its antimicrobial effect. In this work, the green synthesis of AgNPs and their functionalization with chitosan (AgNPs@Chi) was performed, and their antifungal activity investigated against the foremost species responsible for causing sporotrichosis, Sporothrix brasiliensis and Sporothrix schenckii. In vitro studies revealed inhibitory concentrations ranging from 0.12–1 μg/ml for both nanocomposites (NCs). Silver release in suspension displayed chitosan as a potential vehicle for continuous silver discharge, with a complete release after 52 days. No synergistic effects were observed in vitro when the NCs were combined with itraconazole or amphotericin B. Treatment of S. brasiliensis with NCs caused morphological deformities, cell membrane discontinuity and an intense cytoplasmic degeneration. Remarkably, both NCs induced the growth and migration of keratinocytes and fibroblasts when compared to control conditions. In addition, functionalization of AgNPs with chitosan significantly reduced its hemolytic activity, suggesting their potential use in vivo. Finally, silver nanocomposites were used as a daily topical treatment in a murine model of subcutaneous sporotrichosis, showing the ability to reduce the Sporothrix infection and stimulate tissue repair. In combination, our results demonstrate that AgNPs@Chi can be a non-toxic and efficient alternative for sporotrichosis.

Consensus guidelines for the diagnosis and management of invasive fungal disease due to moulds other than Aspergillus in the haematology/oncology setting, 2021

Invasive fungal disease (IFD) due to moulds other than Aspergillus is a significant cause of mortality in patients with malignancies or post haemopoietic stem cell transplantation. The current guidelines focus on the diagnosis and management of the common non-Aspergillus moulds (NAM), such as Mucorales, Scedosporium species (spp.), Lomentospora prolificans and Fusarium spp. Rare but emerging NAM including Paecilomyces variotii, Purpureocillium lilacinum and Scopulariopsis spp. are also reviewed. Culture and histological examination of tissue biopsy specimens remain the mainstay of diagnosis, but molecular methods are increasingly being used. As NAM frequently disseminate, blood cultures and skin examination with biopsy of any suspicious lesions are critically important. Treatment requires a multidisciplinary approach with surgical debridement as a central component. Other management strategies include control of the underlying disease/predisposing factors, augmentation of the host response and the reduction of immunosuppression. Carefully selected antifungal therapy, guided by susceptibility testing, is critical to cure. We also outline novel antifungal agents still in clinical trial which offer substantial potential for improved outcomes in the future. Paediatric recommendations follow those of adults. Ongoing epidemiological research, improvement in diagnostics and the development of new antifungal agents will continue to improve the poor outcomes that have been traditionally associated with IFD due to NAM.

Consensus guidelines for the diagnosis and management of cryptococcosis and rare yeast infections in the haematology/oncology setting, 2021

Cryptococcosis caused by the Cryptococcus neoformans-Cryptococcus gattii complex is an important opportunistic infection in people with immunodeficiency, including in the haematology/oncology setting. This may manifest clinically as cryptococcal meningitis or pulmonary cryptococcosis, or be detected incidentally by cryptococcal antigenemia, a positive sputum culture or radiological imaging. Non-Candida, non-Cryptococcus spp. rare yeast fungaemia are increasingly common in this population. These consensus guidelines aim to provide clinicians working in the Australian and New Zealand haematology/oncology setting with clear guiding principles and practical recommendations for the management of cryptococcosis, while also highlighting important and emerging rare yeast infections and their recommended management.

Delivery strategies of amphotericin B for invasive fungal infections

Invasive fungal infections (IFIs) represent a growing public concern for clinicians to manage in many medical settings, with substantial associated morbidities and mortalities. Among many current therapeutic options for the treatment of IFIs, amphotericin B (AmB) is the most frequently used drug. AmB is considered as a first-line drug in the clinic that has strong antifungal activity and less resistance. In this review, we summarized the most promising research efforts on nanocarriers for AmB delivery and highlighted their efficacy and safety for treating IFIs. We have also discussed the mechanism of actions of AmB, rationale for treating IFIs, and recent advances in formulating AmB for clinical use. Finally, this review discusses some practical considerations and provides recommendations for future studies in applying AmB for combating IFIs.

Low-dose liposomal amphotericin B for antifungal prophylaxis in paediatric allogeneic haematopoietic stem cell transplantation

BACKGROUND

Primary antifungal prophylaxis in paediatric allogeneic HSCT recipients is mainly based on azoles, which can have related toxicity and drug interactions. Low-dose liposomal amphotericin B (L-AmB) is an attractive intravenous alternative because of its low toxicity and lower risk of interactions.

OBJECTIVES

To evaluate the effectiveness and safety of L-AmB (1 mg/kg/day) for primary antifungal prophylaxis in pre-engraftment paediatric HSCT patients.

PATIENTS AND METHODS

Retrospective, observational study including all consecutive patients aged ≤18 years who underwent HSCT and received antifungal prophylaxis with intravenous L-AmB (1 mg/kg/day, from day -1 to 48 h before discharge) between January 2012 and December 2016.

RESULTS

In total, 125 HSCT procedures in 118 patients were included, median age 7.2 years (IQR 4.2-11.5). Haematological malignancies were the main underlying condition (63.6%), and 109 (87.2%) were considered at high risk for invasive fungal infection (IFI). Ten patients (7.7%), all high risk, developed breakthrough IFI (three Candida spp., seven invasive mould infections) and tended to have higher overall mortality. The only statistically significant risk factor for IFI was cytomegalovirus co-infection. Adverse events, all grade I, occurred in 25 (20%), requiring L-AmB withdrawal in one case. Overall survival at 30 days was 99.2%. At study completion, one patient had died of IFI.

CONCLUSIONS

The incidence of breakthrough IFI was comparable to that of previous reports, with a very low rate of significant toxicity. Thus, prophylactic L-AmB may be a safe, effective option for antifungal prophylaxis in the pre-engraftment phase for children undergoing HSCT, even those at high risk.

[Liposomal amphotericin B: Clinical pharmacology, pharmacokinetics and pharmacodynamics]

Liposomal amphotericin B is a lipid formulation of the antifungal drug amphotericin B with some distinguishing characteristics in its pharmacological behavior that entail some clinical differences of great interest. The significant improvement in the systemic and renal tolerability is one of them. This fact is related to the great stability of the liposome, promoted by its negative charge, the presence of cholesterol and the remarkable thermo-stability of the remaining lipids that compose it. In this situation, amphotericin B seems to be released from the liposome not spontaneously but when the liposome binds to the ergosterol in the fungal cell membrane. For this reason, there is almost no free amphotericin B in plasma or tissues, although it seems that its availability is greater when there is fungal infection. As a consequence, when the pharmacokinetic behavior is studied, the concentration and availability of liposomal amphotericin B are very high, and its volume of distribution is reduced in comparison with the other formulations.

Polymeric and Lipid Nanoparticles: Which Applications in Pediatrics?

This review aims to provide the state of the art on polymeric and lipid nanoparticles, used or suggested to approach pediatric diseases’ problems and needs, and to inspire new researches in this field. Several drugs are currently not available in formulations suitable for pediatric patients. The United States Pediatric Formulation Initiative suggested applying new technologies to pediatric drug formulations, for instance, nanotechnology. The literature analysis showed that polymeric and lipid nanoparticles have been widely studied to treat pediatric diseases, and albumin nanoparticles and liposomes are already used in clinical practice. Nevertheless, these studies are focused almost exclusively on pediatric cancer treatment. Although nanomedicine may solve many needs of pediatric diseases and medicines, the unavailability of data on pharmacokinetics, safety and efficacy of both drugs and nanoparticles in pediatric patients limits the development of new pediatric medicines based on nanoparticles. Therefore, nanomedicine applied in pediatrics remains a significant challenge in the near future.

Preclinical safety evaluation of amphotericin A21: A novel antifungal

Safety studies are essential in drug development. This study evaluates the safety of Amphotericin A21 (AmB-A21), a derivative of amphotericin B with antifungal therapeutic potential. We performed a chronic toxicity study, a targeted organ study and a dermal irritation test. To evaluate chronic toxicity, 18 male adult rats were treated orally with AmB-21 (2 mg/kg) for 26 weeks. The effects on body-weight and animal health were measured, and haematological, clinical chemistry and histopathological tests were conducted on various organs. In the target organ toxicity study, male adult rats received a daily oral dose of AmB-21 (2 mg/kg) for 6 and 17 weeks; testicle histology and testosterone levels were then evaluated. For the dermal irritation study, AmB-21 (200 and 1000 mg/kg) was placed on the skin of adult male rabbits; macroscopic and microscopic studies, as well as haematological and clinical chemistry tests were then conducted. The chronic toxicity study revealed that AmB-21 caused testicle damage, and the testicle-targeted study showed structural alterations and changes in testosterone levels at 17 weeks. However, these alterations were no longer observed 8 weeks after discontinuation of treatment, and the testes showed very similar characteristics to those in the control group. The dermal irritation study showed skin thickening and reddening in rabbits treated with 2000 mg of AmB-A21 after 14 days of exposure. This same group also showed changes in liver enzymes, renal parameters and platelet levels. Based on our results, we consider AmB-21 to be a potential candidate for safe, long-term antifungal treatment given its reduced side effects.

Efficacy of liposomal amphotericin against febrile neutropenia in pediatric patients receiving prophylactic voriconazole

BACKGROUND

The risk factors for invasive fungal infection have gradually become evident for pediatric patients with hematological diseases. Here we analyze the efficacy of liposomal amphotericin (L-AMB) for pediatric patients with febrile neutropenia using prophylactic voriconazole (VRCZ).

METHOD

We administered L-AMB (2.5 mg/kg/day) in patients with febrile neutropenia who were receiving prophylactic VRCZ (10 mg/kg/day, orally) and were resistant to second-line antibiotics therapy. Thirteen patients (5 males, 8 females) with 19 febrile neutropenia episodes were targeted in this analysis. The median age of the patients was 14 years (range, 1-19 years). Eighteen out of 19 episodes occurred in patients with acute myeloid leukemia, with the remaining episode occurring in a patient with acute unclassified leukemia.

RESULTS

The median period from start of L-AMB administration to resolution of fever was 4 days (1-27 days). In 15 out of 19 episodes, fever resolved within 5 days from commencement of L-AMB administration. Using criteria proposed by T. J. Walsh et al., the success rate of L-AMB for febrile neutropenia was 89.5% in this study.

CONCLUSIONS

Although the sample size of our study was small, the extremely high efficacy of L-AMB warrants its administration in patients with febrile neutropenia who are receiving VRCZ.

Contribution of Population Pharmacokinetics of Glycopeptides and Antifungals to Dosage Adaptation in Paediatric Onco-hematological Malignancies: A Review

The response to medications in children differs not only in comparison to adults but also between children of the different age groups and according to the disease. This is true for anti-infectives that are widely prescribed in children with malignancy. In the absence of pharmacokinetic/pharmacodynamic paediatric studies, dosage is frequently based on protocols adapted to adults. After a short presentation of the drugs, we reviewed the population pharmacokinetic studies available for glycopeptides (vancomycin and teicoplanin, n = 5) and antifungals (voriconazole, posaconazole, and amphotericin B, n = 9) currently administered in children with onco-hematological malignancies. For each of them, we reported the main study characteristics including identified covariates affecting pharmacokinetics and proposed paediatric dosage recommendations. This review highlighted the very limited amount of data available, the lack of consensus regarding PK/PD targets used for dosing optimization and regarding dosage recommendations when available. Additional PK studies are urgently needed in this specific patient population. In addition to pharmacokinetics, efficacy may be altered in immunocompromised patients and prospective clinical evaluation of new dosage regimen should be provided as they are missing in most cases.

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.

Administration and Dosing of Systemic Antifungal Agents in Pediatric Patients

Neonates and immunosuppressed/immunocompromised pediatric patients are at high risk of invasive fungal diseases. Appropriate antifungal selection and optimized dosing are imperative to the successful prevention and treatment of these life-threatening infections. Conventional amphotericin B was the mainstay of antifungal therapy for many decades, but dose-limiting nephrotoxicity and infusion-related adverse events impeded its use. Despite the development of several new antifungal classes and agents in the past 20 years, and their now routine use in at-risk pediatric populations, data to guide the optimal dosing of antifungals in children are limited. This paper reviews the spectra of activity for approved antifungal agents and summarizes the current literature specific to pediatric patients regarding pharmacokinetic/pharmacodynamic data, dosing, and therapeutic drug monitoring.

Pharmacokinetics of nanotechnology-based formulations in pediatric populations

The development of therapeutics for pediatric use has advanced in the last few decades. However, off-label use of adult medications in pediatrics remains a significant clinical problem. Furthermore, the development of therapeutics for pediatrics is challenged by the lack of pharmacokinetic (PK) data in the pediatric population. To promote the development of therapeutics for pediatrics, the United States Pediatric Formulation Initiative recommended the investigation of nanotechnology-based delivery systems. Therefore, in this review, we provided comprehensive information on the PK of nanotechnology-based formulations from preclinical and clinical studies in pediatrics. Specifically, we discuss the relationship between formulation parameters of nanoformulations and PK of the encapsulated drug in the context of pediatrics. We review nanoformulations that include dendrimers, liposomes, polymeric long-acting injectables (LAIs), nanocrystals, inorganic nanoparticles, polymeric micelles, and protein nanoparticles. In addition, we describe the importance and need of PK modeling and simulation approaches used in predicting PK of nanoformulations for pediatric applications.

Therapeutic drug monitoring of systemic antifungal agents: a pragmatic approach for adult and pediatric patients

Introduction: Therapeutic drug monitoring (TDM) has been shown to optimize the management of invasive fungal infections (IFIs), particularly for select antifungal agents with a well-defined exposure-response relationship and an unpredictable pharmacokinetic profile or a narrow therapeutic index. Select triazoles (itraconazole, voriconazole, and posaconazole) and flucytosine fulfill these criteria, while the echinocandins, fluconazole, isavuconazole, and amphotericin B generally do not do so. Given the morbidity and mortality associated with IFIs and the challenges surrounding the use of currently available antifungal agents, TDM plays an important role in therapy.Areas covered: This review seeks to describe the rationale for TDM of antifungal agents, summarize their pharmacokinetic and pharmacodynamic properties, identify treatment goals for efficacy and safety, and provide recommendations for optimal dosing and therapeutic monitoring strategies.Expert opinion: Several new antifungal agents are currently in development, including compounds from existing antifungal classes with enhanced pharmacokinetic or safety profiles as well as agents with novel targets for the treatment of IFIs. Given the predictable pharmacokinetics of these newly developed agents, use of routine TDM is not anticipated. However, expanded knowledge of exposure-response relationships of these compounds may yield a role for TDM to improve outcomes for adult and pediatric patients.

Extended Dosing Regimens for Fungal Prophylaxis

Invasive fungal diseases carry high morbidity and mortality in patients undergoing chemotherapy for hematological malignancies or allogeneic hematopoietic stem cell transplantation. In order to prevent these life-threatening infections, antifungal chemoprophylaxis plays an important role in daily clinical practice. Broad-spectrum antifungal triazoles are widely used but exhibit disadvantages such as relevant drug-drug interactions. Therefore, amphotericin B products or echinocandins can be an alternative in selected patient populations. As these compounds are available as intravenous formulations only, there is growing interest in extended dosing regimens. Although not approved for these agents, this strategy is a rational option, as these compounds have properties suitable for this strategy, including dose-proportional pharmacokinetics, prolonged elimination half-life, and a large therapeutic window. As the use of extended dosing regimens in antifungal prophylaxis is expanding in clinical practice, we reviewed the pharmacokinetic and pharmacodynamic rationale for this strategy, animal model data, dose escalation studies, and clinical trials supporting this concept.

ESCMID-ECMM guideline: diagnosis and management of invasive aspergillosis in neonates and children

SCOPE

Presenting symptoms, distributions and patterns of diseases and vulnerability to invasive aspergillosis (IA) are similar between children and adults. However, differences exist in the epidemiology and underlying conditions, the usefulness of newer diagnostic tools, the pharmacology of antifungal agents and in the evidence from interventional phase 3 clinical trials. Therefore, the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) and the European Confederation of Medical Mycology (ECMM) have developed a paediatric-specific guideline for the diagnosis and management of IA in neonates and children.

METHODS

Review and discussion of the scientific literature and grading of the available quality of evidence was performed by the paediatric subgroup of the ESCMID-ECMM-European Respiratory Society (ERS) Aspergillus disease guideline working group, which was assigned the mandate for the development of neonatal- and paediatric-specific recommendations.

QUESTIONS

Questions addressed by the guideline included the epidemiology of IA in neonates and children; which paediatric patients may benefit from antifungal prophylaxis; how to diagnose IA in neonates and children; which antifungal agents are available for use in neonates and children; which antifungal agents are suitable for prophylaxis and treatment of IA in neonates and children; what is the role of therapeutic drug monitoring of azole antifungals; and which management strategies are suitable to be used in paediatric patients. This guideline provides recommendations for the diagnosis, prevention and treatment of IA in the paediatric population, including neonates. The aim of this guideline is to facilitate optimal management of neonates and children at risk for or diagnosed with IA.

Clinical Pharmacokinetics, Pharmacodynamics, Safety and Efficacy of Liposomal Amphotericin B

Since its introduction in the 1990s, liposomal amphotericin B (LAmB) continues to be an important agent for the treatment of invasive fungal diseases caused by a wide variety of yeasts and molds. This liposomal formulation was developed to improve the tolerability of intravenous amphotericin B, while optimizing its clinical efficacy. Since then, numerous clinical studies have been conducted, collecting a comprehensive body of evidence on its efficacy, safety, and tolerability in the preclinical and clinical setting. Nevertheless, insights into the pharmacokinetics and pharmacodynamics of LAmB continue to evolve and can be utilized to develop strategies that optimize efficacy while maintaining the compound's safety. In this article, we review the clinical pharmacokinetics, pharmacodynamics, safety, and efficacy of LAmB in a wide variety of patient populations and in different indications, and provide an assessment of areas with a need for further clinical research.

Invasive Candidiasis in Infants and Children: Recent Advances in Epidemiology, Diagnosis, and Treatment

This paper reviews recent advances in three selected areas of pediatric invasive candidiasis: epidemiology, diagnosis, and treatment. Although the epidemiological trends of pediatric invasive candidiasis illustrate a declining incidence, this infection still carries a heavy burden of mortality and morbidity that warrants a high index of clinical suspicion, the need for rapid diagnostic systems, and the early initiation of antifungal therapy. The development of non-culture-based technologies, such as the T2Candida system and (1→3)-β-d-glucan detection assay, offers the potential for early laboratory detection of candidemia and CNS candidiasis, respectively. Among the complications of disseminated candidiasis in infants and children, hematogenous disseminated Candida meningoencephalitis (HCME) is an important cause of neurological morbidity. Detection of (1→3)-β-d-glucan in cerebrospinal fluid serves as an early diagnostic indicator and an important biomarker of therapeutic response. The recently reported pharmacokinetic data of liposomal amphotericin B in children demonstrate dose–exposure relationships similar to those in adults. The recently completed randomized clinical trial of micafungin versus deoxycholate amphotericin B in the treatment of neonatal candidemia provides further safety data for an echinocandin in this clinical setting.

Promising nanotherapy in treating leishmaniasis

Leishmaniases are infectious diseases caused by an intracellular protozoan in humans by 20 different species of Leishmania among more than 53 species. There are at least twelve million cases of infections worldwide and three hundred and fifty million people are at risk in at least 98 developing countries in Africa, South-East Asia, and the Americas. Only Brazil presented high burden for both visceral leishmaniasis (VL) and cutaneous (CL). Chemotherapy is the main means of dealing with this infection. Nevertheless, only a few effective drugs are available, and each has a particular disadvantage; toxicity and long-term regimens compromise most chemotherapeutic options, which decreases patient compliance and adherence to the treatment and consequently the emergence of drug-resistant strains. Nano drug delivery systems (NanoDDS) can direct antileishmanial drug substances for intracellular localization in macrophage-rich organs such as bone marrow, liver, and spleen. This strategy can improve the therapeutic efficacy and reduce the toxic effects of several antileishmanial drug substances. This review is an effort to comprehensively compile recent findings, with the aim of advancing understanding of the importance of nanotechnology for treating leishmaniases.

Analysis of Hypokalemia as a Side Effect of Liposomal Amphotericin in Pediatric Patients

BACKGROUND

Liposomal amphotericin (L-AMB) is a widely used broad-spectrum antifungal drug. Although L-AMB demonstrates better safety compared with amphotericin, renal dysfunction and hypokalemia are well-known adverse effects of L-AMB.

METHOD

We analyzed 56 episodes in 40 children and adolescents who received L-AMB therapy to determine risk factors of hypokalemia.

RESULTS

Hypokalemia (<3.0 mEq/L continuously for more than 2 episodes) was observed in 31 of 56 episodes (55.4%). The median onset of hypokalemia was at 10 days on L-AMB (range, 3-54 days), and the median cumulative dose of L-AMB at occurrence of hypokalemia was 25 mg/kg (range, 10-167.5 mg/kg). None of the patients with hypokalemia had solid tumors, and they had significantly higher estimated glomerular filtration rates than those with normokalemia (P = 0.013). Seven of 25 (28.0%) patients in the normokalemia group and 1 of 31 (3.2%) patients in the hypokalemia group had eGFRs of <90 mL/min/1.73 m(2) (P = 0.017).

CONCLUSION

Although the reason for the association between estimated glomerular filtration rates and hypokalemia is unclear, assessing the estimated glomerular filtration rates before L-AMB administration may predict the development of hypokalemia.