Triad of acute infusion-related reactions associated with liposomal amphotericin B: analysis of clinical and epidemiological characteristics

Drug repurposing for fungal infections

The rise of multidrug-resistant bacteria is a well-recognized threat to world health, necessitating the implementation of effective treatments. This issue has been identified as a top priority on the global agenda by the World Health Organization. Certain strains, such as Candida glabrata, Candida krusei, Candida lusitaniae, Candida auris, select cryptococcal species, and opportunistic Aspergillus or Fusarium species, have significant intrinsic resistance to numerous antifungal medicines. This inherent resistance and subsequent suboptimal clinical outcomes underscore the critical imperative for enhanced therapeutic alternatives and management protocols. The challenge of effectively treating fungal infections, compounded by the protracted timelines involved in developing novel drugs, underscores the pressing need to explore alternative therapeutic avenues. Among these, drug repurposing emerges as a particularly promising and expeditious solution, providing cost-effective solutions and safety benefits. In the fight against life-threatening resistant fungal infections, the idea of repurposing existing medications has encouraged research into both established and new compounds as a last-resort therapy. This chapter seeks to provide a comprehensive overview of contemporary antifungal drugs, as well as their key resistance mechanisms. Additionally, it seeks to provide insight into the antimicrobial properties of non-traditional drugs, thereby offering a holistic perspective on the evolving landscape of antifungal therapeutics.

Nonclinical Testing Evaluation of Liposomes as Drug Delivery Systems

Various marketed drugs, as well as many in-development, have utilized liposomes, vesicles composed of one or more phospholipid bilayers, as a drug delivery system, often with the statement that they are "non-toxic" materials. This paper examined safety testing considerations and reviewed nonclinical packages used to support the safe clinical use and marketing of drugs using a liposomal drug delivery system, including liposome-only study findings. It was found that most experience has come from use of an established drug (especially in the oncology field) in a liposome formulation with known excipients. From this knowledge, it is proposed that the minimal package of studies (using an oncology indication as an example) needed to support clinical entry should include in vivo pharmacology in selected mouse xenograft models, pharmacokinetic characterization showing enhanced kinetics or disposition and including tumor exposure evaluation along with repeat-dose toxicity testing in one species. It was also found that the liposomes used in drug delivery systems are not truly "non-toxic" materials. However, the majority of findings in toxicity testing relate to macrophage processing of large amounts of lipid material, with no human known safety consequence. Of note, however, are cases of hypersensitivity for some PEGylated liposome forms which translate to the clinic.

Meglumine antimoniate was associated with a higher cure rate than liposomal amphotericin B in the treatment of American tegumentary leishmaniasis: A retrospective cohort study from a Leishmania braziliensis-endemic area

Background

Pentavalent antimonials (PAs) are the primary therapeutic option for American tegumentary leishmaniasis (ATL). However, the use of these drugs is complicated by adverse events (AEs), resistance and contraindications. Alternative therapies relative effectiveness is not well established.

Objective

This study compared the effectiveness of liposomal amphotericin B (LAB) with intravenous meglumine antimoniate (NMG) in the treatment of ATL. We also analysed and compared associated AEs and treatment interruption rates.

Methods

This was a retrospective cohort study from Brazil. The potential risk factors for the primary outcome were age, sex, total cutaneous lesion area, presence of mucosal lesions, AEs and treatment interruption. The primary outcome was lesion healing within 6 months of treatment. AEs and treatment interruption were also analysed. Multiple analytic strategies were employed to evaluate the reliability of the results.

Results

Before propensity score (PS) matching, patients in the LAB group were older and had a higher frequency of mucosal lesions. The NMG group had a higher cure rate than the LAB group (cure rate 88% versus 55% respectively) in the adjusted analysis (relative risk (RR)=1.55 95% CI: 1.19 - 2.02) and after PS matching (RR=1.63 95% CI: 1.20 - 2.21). NMG group had a higher AE rate (event rate 52% versus 44%) in the adjusted analysis (RR= 1.61, 95% CI: 1.06 - 2.43, p=0.02), but this result was not observed after PS matching (RR= 0.87, 95% CI: 0.49 -1.52, p= 0.61).

Conclusions

We observed that the NMG group had a higher cure rate than the LAB group, with an equivocally higher EV rate in the adjusted analysis.

Eravacycline infusion–related hypoesthesia: A case report

Disclaimer

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Purpose

Eravacycline (ERV) is often used for drug-resistant gram-negative and nontuberculous mycobacteria (NTM) infections, but infusion site reactions are a potential adverse effect. We report a case of severe hypoesthesia secondary to ERV infusion.

Summary

A 74-year-old man presented with dyspnea, shortness of breath, and hemoptysis after being treated for community-acquired pneumonia. On the basis of respiratory cultures performed several weeks before the index hospitalization, he was diagnosed with Mycobacterium chelonae pneumonia. On hospital day (HD) 2, the infectious diseases consult team, guided by susceptibilities, initiated a regimen of azithromycin, levofloxacin, and ERV 80 mg (1 mg/kg) intravenously every 12 hours infused over 1 hour in 250 mL of normal saline. Approximately 25 minutes after the ERV infusion began, the patient reported tingling and numbness in his fingers, hands, and mouth, with shooting pain in his head. Symptoms resolved with cessation of the ERV infusion. On HD 3, the same ERV dose and volume was administered with an extended infusion time of 2 hours. The patient experienced the same reaction after 58 minutes, which ceased shortly after the infusion was stopped. Use of ERV was subsequently discontinued. The Naranjo adverse drug reaction probability scale score was 9, indicating a definite reaction. A review of the Food and Drug Administration Adverse Event Reporting System through March 2021 identified 22 ERV-associated events. Among these, 18% appear to be related to ERV infusions. Published results from phase 3 clinical trials did not document any hypoesthesia. It is unknown whether there is a correlation between concentration, dose, or infusion time and associated reactions.

Conclusion

This is a unique case of severe hypoesthesia secondary to ERV infusion leading to drug discontinuation. More data are needed to determine effective mitigation strategies.

Treating pediatric cutaneous Leishmania tropica with systemic liposomal amphotericin B: A retrospective, single-center study

Leishmania tropica (L. tropica) cutaneous leishmaniasis (CL) is associated with high morbidity and low response rate to therapy, especially in pediatric patients. Intravenous (IV) liposomal amphotericin B (LAmB) has been used off-label as a treatment for L. tropica CL for many years. However, data regarding its efficacy and safety in children is lacking. In order to evaluate the efficacy and safety of IV LAmB for treating pediatric patients with L. tropica, we retrospectively reviewed electronic medical records of 24 children who were diagnosed with L. tropica CL and treated with IV LAmB during 2014-2020, at a tertiary medical center in Israel. Fourteen (58%) completed the treatment protocol and 10 (42%) experienced an infusion-related adverse event (IRAE) leading to treatment termination. Complete response was noted in 6/14 (43%) patients, while 8/14 (57%) failed to respond. Lower response rate was noted in lesions involving the mid-facial area. The relatively low response rate is speculated to result from a low dose of LAmB, short follow-up period, and difficult to treat anatomic locations. The observation of a lower response rate for mid-facial lesions should be validated in larger cohorts. The highrisk of IRAE should be considered in physician decisions regarding this treatment.

Amphotericin-Associated Infusion-Related Reactions: A Narrative Review of Pre-Medications

PURPOSE

Amphotericin B has been reported to cause infusion-related adverse effects (IRAEs). To prevent IRAEs, pre-medications may be administered prior to the administration of amphotericin B. The effects of different formulations of amphotericin B (amphotericin B deoxycholate and lipid formulations), duration of infusion, and utility of pre-medications in preventing IRAEs are reviewed.

METHODS

PubMed, Ovid Medline, Embase, Web of Science, the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, and the Scopus databases were searched with the following search terms: pre-medication, amphotericin B, and its related compounds. Upon review, a total of 39 publications were considered for inclusion.

FINDINGS

In vitro and in vivo studies have reported that amphotericin B deoxycholate stimulates pro-inflammatory cytokine genes causing IRAEs. Nonetheless, the clinical literature has reported that IRAEs occur among patients who received pre-medications. In comparison to amphotericin B deoxycholate, lipid-based formulations of amphotericin may result in a lower or similar risk for IRAEs.

IMPLICATIONS

The routine use of pre-medications to prevent IRAEs after the administration of amphotericin B (amphotericin B deoxycholate or lipid formulations) would not be warranted.

Adverse Drug Reaction of Antifungals in the Management of Black Fungus: A Tertiary Care Centre Experience

In India, COVID-19 has led to a surge in cases of a potentially fatal fungal infection called mucormycosis, popularly known as “black fungus.” Intravenous amphotericin B is the only available drug for salvage therapy. Efforts to improve its therapeutic efficacy and decrease its nephrotoxicity have focussed on the reformulation of AmB in three new lipid formulations such amphotericin B lipid complex (Abelcet), amphotericin B colloidal dispersion (Amphotec), and liposomal amphotericin B (AmBisome). The aim of this study is (1) to evaluate the adverse drug reaction of various formulations of amphotericin B used for the treatment of rhinooculocerebralmucormycosis in Indian population. (2) to evaluate the adverse drug reaction of injectable form of posaconazole. This prospective observational study was done on a random sample of 110 patients who got admitted for the management of rhinooculocerebral mucormycosis in a tertiary care centre of middle india… The patients were assessed for the adverse reactions following the administration of various antifungal medication and the findings were analysed. All the 110 patients had received two forms of Amphotericin B (liposomal Amphotericin B and Amphotericin B lipid complex) and Posaconazole injection. 60 patients had received all three forms of Amphotericin B. Out of the 110 patients who received Liposomal amphotericin B, only 2 patients developed adverse drug reaction while in 110 patients who received Amphotericin B Lipid complex, 7 patients had adverse drug effects. Lyophilised amphotericin B had been administered to 60 patients in which 51 patients developed adverse drug reaction and in them one patient went to congestive cardiac failure. Injection posaconazole had been administered to 110 patients in which 72 patients developed drug reaction. In spite of its proven track record of Amphotericin B, its well-known side effects and toxicity will sometimes require discontinuation of therapy despite a life-threatening systemic fungal infection. Lipid formulations of AmB are better tolerated than AmB deoxycholate but infusional drug reactions have been reported in lipid formulation too. So improved strategies for the management of infusion related adverse events are required.

Conventional Amphotericin B Associated Nephrotoxicity in Patients With Hematologic Malignancies

Introduction: Amphotericin B (AmB-d) is one of the most effective therapeutic options against frequently life-threatening systemic fungal infections in patients with hematologic malignancies. However, significant adverse effects including nephrotoxicity associated with its use limit its more widespread use. The objectives of our study were to determine the incidence of AmB-d associated nephrotoxicity, to evaluate clinical and epidemiological characteristics of patients, and to support the notion that conventional amphotericin B remains a valid therapeutic option among hematologic patients with proper patient selection.

Materials and methods: A total of 110 patients with hematologic malignancies were admitted to our Hematology Unit between January 2014 and November 2017 who required anti-fungal therapy during intensive systemic chemotherapy. The incidence of AmB-d associated nephrotoxicity, side effect profile, time to nephrotoxicity, and clinical and epidemiological characteristics associated with treatment success were assessed retrospectively.

Results: Of the 110 patients receiving AmB-d, 70 (63.6%) were male and 40 (36.4%) were female. The mean age of participants was 44 years. The most common diagnosis was acute myeloid leukemia (n=53, 48.2%), and the most common chemotherapy protocol was 7 + 3 remission-induction (cytarabine 100 mg/m² days 1-7, Idarubicin 12 mg/m² days 1-3; n=24, 21.8%). In 56.4% of the patients, antifungal therapy was given empirically. In 40 patients (36.4%), nephrotoxicity was observed following antifungal treatment, and only four patients had stage 3 renal failure. The mean duration of time to nephrotoxicity from initiation of amphotericin B was four days (min: 2, max: 31). All patients were found to receive at least one additional potential nephrotoxic treatment during the antifungal treatment process. 

Conclusion: AmB-d is associated with a significant risk of nephrotoxicity. In most hematological patients, antifungal treatment is initiated empirically, and patients received prolonged courses of treatment. Therefore, it is plausible to initiate such treatment with AmB-d, when one considers the already high treatment costs in this patient group as well as the fact that AmB-d offers similar efficacy to antifungal agents at a lower cost. AmB-d may be recommended as a first-line agent in this patient group with the introduction of newer and more costly antifungal agents when needed, on the basis of the fact that these patients can be closely monitored in a hospital setting, reversible nature of nephrotoxicity upon discontinuation, and rare occurrence of severe renal failure requiring dialysis.

Pharmacological management of antifungal agents in pulmonary aspergillosis: an updated review

INTRODUCTION

Aspergillus may cause different types of lung infections: invasive, chronic pulmonary or allergic bronchopulmonary aspergillosis. Pharmacological management with antifungals poses as a challenge. Patients diagnosed with pulmonary aspergillosis are complex, as well as the problems associated with antifungal agents.

AREAS COVERED

This article reviews the pharmacology of antifungal agents in development and currently used to treat pulmonary aspergillosis, including the mechanisms of action, pharmacokinetics, pharmacodynamics, dosing, therapeutic drug monitoring and safety. Recommendations to manage situations that arise in daily clinical practice are provided. A literature search of PubMed was conducted on November 15^th, 2020 and updated on March 30^th, 2021.

EXPERT OPINION

Recent and relevant developments in the treatment of pulmonary aspergillosis have taken place. Novel antifungals with new mechanisms of action that extend antifungal spectrum and improve pharmacokinetic-related aspects, drug-drug interactions and safety are under current study. For those antifungals already marketed, new data related to pharmacokinetics, pharmacodynamics, dose adjustments in special situations, therapeutic drug monitoring and safety are available. To maximize efficacy and reduce the risk of associated toxicities, it is essential to choose the most appropriate antifungal; optimize its dose, interval, route of administration and length of treatment; and prevent side effects.

Drug repurposing strategies in the development of potential antifungal agents

Abstract

The morbidity and mortality caused by invasive fungal infections are increasing across the globe due to developments in transplant surgery, the use of immunosuppressive agents, and the emergence of drug-resistant fungal strains, which has led to a challenge in terms of treatment due to the limitations of three classes of drugs. Hence, it is imperative to establish effective strategies to identify and design new antifungal drugs. Drug repurposing is a potential way of expanding the application of existing drugs. Recently, various existing drugs have been shown to be useful in the prevention and treatment of invasive fungi. In this review, we summarize the currently used antifungal agents. In addition, the most up-to-date information on the effectiveness of existing drugs with antifungal activity is discussed. Moreover, the antifungal mechanisms of existing drugs are highlighted. These data will provide valuable knowledge to stimulate further investigation and clinical application in this field.

Key points

• Conventional antifungal agents have limitations due to the occurrence of drug-resistant strains.

• Non-antifungal drugs act as antifungal agents in various ways toward different targets.

• Non-antifungal drugs with antifungal activity are demonstrated as effective antifungal strategies.

Nanoparticles as a Tool for Broadening Antifungal Activities

Fungal infections are diseases that are considered neglected although their infection rates have increased worldwide in the last decades. Thus, since the antifungal arsenal is restricted and many strains have shown resistance, new therapeutic alternatives are necessary. Nanoparticles are considered important alternatives to promote drug delivery. In this sense, the objective of the present study was to evaluate the contributions of newly developed nanoparticles to the treatment of fungal infections. Studies have shown that nanoparticles generally improve the biopharmaceutical and pharmacokinetic characteristics of antifungals, which is reflected in a greater pharmacodynamic potential and lower toxicity, as well as the possibility of prolonged action. It also offers the proposition of new routes of administration. Nanotechnology is known to contribute to a new drug delivery system, not only for the control of infectious diseases but for various other diseases as well. In recent years, several studies have emphasized its application in infectious diseases, presenting better alternatives for the treatment of fungal 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.

Nano- and Microformulations to Advance Therapies for Visceral Leishmaniasis

Visceral leishmaniasis (VL) is a deadly, vector-borne, neglected tropical disease endemic to arid parts of the world and is caused by a protozoan parasite of the genus Leishmania. Chemotherapy is the primary treatment for this systemic disease, and multiple potent therapies exist against this intracellular parasite. However, several factors, such as systemic toxicity, high costs, arduous treatment regimen, and rising drug resistance, are barriers for effective therapy against VL. Material-based platforms have the potential to revolutionize chemotherapy for leishmaniasis by imparting a better pharmacokinetic profile and creating patient-friendly routes of administration, while also lowering the risk for drug resistance. This review highlights promising drug delivery strategies and novel therapies that have been evaluated in preclinical models, demonstrating the potential to advance chemotherapy for VL.

Primary Cutaneous Coccidioidomycosis: An Update

Coccidioidomycosis is an endemic mycosis of the southern United States, Northern Mexico, and South America. Primary cutaneous coccidioidomycosis, despite being a very rare clinical presentation, has shown an increasing incidence. An extensive literature search for cutaneous coccidioidomycosis cases was performed using the OLDMEDLINE, PubMed, Cochrane, LILACS and Google Scholar databases for studies published from January 1927 through December 21, 2019. Forty-two observational studies were included totaling 82 cases of primary cutaneous coccidioidomycosis. Narrative reviews, systematic reviews, and meta-analyses were also included. Additionally, an original case was included. Patients with primary cutaneous coccidioidomycosis share the same geographical and epidemiological characteristics as those with pulmonary or disseminated coccidioidomycosis. Most of the imported cases came from endemic areas. A large portion of cases had prior local skin trauma. Tissue culture is still the leading diagnostic method; nevertheless, molecular techniques such as polymerase chain reaction (PCR) are currently relevant to differentiate between species. First-line treatment consists of azoles; however, it has an excellent prognosis even without treatment. Primary cutaneous coccidioidomycosis should be considered a differential diagnosis of unusual infections or neoformations in any part of the body in resident populations of endemic areas or in patients with a previous history of travel to these areas.

Potentially Inappropriate Prescriptions in Heart Failure with Reduced Ejection Fraction (PIP-HFrEF)

Heart failure (HF) is a chronic debilitating and potentially life-threatening condition. Heart Failure patients are usually at high risk of polypharmacy and consequently, potentially inappropriate prescribing leading to poor clinical outcomes. Based on the published literature, a comprehensive HF-specific prescribing review tool is compiled to avoid medications that may cause HF or harm HF patients and to optimize the prescribing practice of HF guideline-directed medical therapies. Recommendations are made in line with the last versions of ESC guidelines, ESC position papers, scientific evidence, and experts' opinions.

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.

Choosing the Right Antifungal Agent in ICU Patients

Fungi are responsible for around 20% of microbiologically documented infections in intensive care units (ICU). In the last decade, the incidence of invasive fungal infections (IFI), including candidemia, has increased steadily because of increased numbers of both immunocompromised and ICU patients. To improve the outcomes of patients with IFI, intensivists need to be aware of the inherent challenges. This narrative review summarizes the features of routinely used treatments directed against IFI in non-neutropenic ICU patients, which include three classes of antifungals: polyenes, azoles, and echinocandins. ICU patients’ pathophysiological changes are responsible for deep changes in the pharmacokinetics of antifungals. Moreover, drug interactions affect the response to antifungal treatments. Consequently, appropriate antifungal dosage is a challenge under these special conditions. Dosages should be based on renal and liver function, and serum concentrations should be monitored. This review summarizes recent guidelines, focusing on bedside management.

The Rise of Coccidioides: Forces Against the Dust Devil Unleashed

Coccidioidomycosis (Valley fever) is a fungal disease caused by the inhalation of Coccidioides posadasii or C. immitis. This neglected disease occurs in the desert areas of the western United States, most notably in California and Arizona, where infections continue to rise. Clinically, coccidioidomycosis ranges from asymptomatic to severe pulmonary disease and can disseminate to the brain, skin, bones, and elsewhere. New estimates suggest as many as 350,000 new cases of coccidioidomycosis occur in the United States each year. Thus, there is an urgent need for the development of a vaccine and new therapeutic drugs against Coccidioides infection. In this review, we discuss the battle against Coccidioides including the development of potential vaccines, the quest for new therapeutic drugs, and our current understanding of the protective host immune response to Coccidioides infection.

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.

Lipsosomal amphotericin B: a review of its properties, function, and use for treatment of cutaneous leishmaniasis

The genus Leishmania includes a number of protozoan parasites that cause a wide range of infections named leishmaniasis. Leishmaniasis may be appear in three clinical forms — cutaneous (CL), visceral, and mucocutaneous (MCL) — with variation in their presentation and severity: diffuse CL and post–kala-azar dermal leishmaniasis). The prevalent signs of CL are nonhealing ulcers on exposed skin, but infected patients may have other dermatologic symptoms. In the 1960s, amphotericin B deoxycholate was introduced as a second-line therapy for CL and MCL. However, widespread administration of the agent was prevented, due to its renal and systemic toxicity, high price, and obstacles to intravenous use in leishmaniasis-endemic regions. Amphotericin B binds to ergosterol in the photogenic cell membranes and causes changes in membrane permeability, leakage of ions, and finally cell death. Compared to amphotericin B deoxycholate, a higher dose of liposomal amphotericin B should be administered to show the treatment effect. A high percentage of liposomal amphotericin B is “fastened” in the liposome and not biologically effective. Amphotericin B deoxycholate has some toxic effects, and liposomal amphotericin B is meaningfully less toxic compared to it. Treatment options for CL are limited, due to variation in species causing CL and pharmacokinetic issues. Amphotericin B is effective against some particular forms of CL.

Current Concepts and Future Directions in the Pharmacology and Treatment of Coccidioidomycosis

Coccidioidomycosis remains a significant clinical problem with substantial morbidity and mortality. The vast majority of infections are asymptomatic and the need for early primary therapy remains controversial. The use of triazole antifungals has improved tolerability of therapy but concerns about acute and long-term toxicities among available agents limit their use. In addition, recent findings of decreased in vitro fluconazole susceptibility to as many as 37% of Coccidioides spp. isolates raises concerns regarding optimal therapy for these infections as fluconazole is commonly used for therapy including central nervous system disease. Thus, new agents from novel antifungal classes are currently in preclinical and clinical development aimed at reducing toxicity and improving outcomes of these serious infections.

Tolerability profile of the current antifungal armoury

The tolerability of available antifungal agents is essential to the final outcome of the management of invasive mycoses. There are limited classes of antifungal agents for use, and they can have serious direct toxicities and/or drug-drug interactions. In this review, we examine the common toxicities noted for antifungal agents and attempt to both identify the issues around the adverse events and provide clinical context for their occurrence in these fragile patients.

Immune reconstitution inflammatory syndrome associated with disseminated histoplasmosis and TNF-alpha inhibition

Endemic fungal infections are a significant problem for patients on TNF-alpha inhibitors. Immune reconstitution inflammatory syndrome, IRIS, can present in patients with waning TNF-alpha inhibition and an endemic fungal infection. There may be a potential role that TNF-alpha inhibitors can play in mitigating IRIS related to disseminated endemic fungal infections.

Antifungal benzo[b]thiophene 1,1-dioxide IMPDH inhibitors exhibit pan-assay interference (PAINS) profiles

Fungi cause serious life-threatening infections in immunocompromised individuals and current treatments are now complicated by toxicity issues and the emergence of drug resistant strains. Consequently, there is a need for development of new antifungal drugs. Inosine monophosphate dehydrogenase (IMPDH), a key component of the de novo purine biosynthetic pathway, is essential for growth and virulence of fungi and is a potential drug target. In this study, a high-throughput screen of 114,000 drug-like compounds against Cryptococcus neoformans IMPDH was performed. We identified three 3-((5-substituted)-1,3,4-oxadiazol-2-yl)thio benzo[b]thiophene 1,1-dioxides that inhibited Cryptococcus IMPDH and also possessed whole cell antifungal activity. Analogs were synthesized to explore the SAR of these hits. Modification of the fifth substituent on the 1,3,4-oxadiazole ring yielded compounds with nanomolar in vitro activity, but with associated cytotoxicity. In contrast, two analogs generated by substituting the 1,3,4-oxadiazole ring with imidazole and 1,2,4-triazole gave reduced IMPDH inhibition in vitro, but were not cytotoxic. During enzyme kinetic studies in the presence of DTT, nucleophilic attack of a free thiol occurred with the benzo[b]thiophene 1,1-dioxide. Two representative compounds with substitution at the 5 position of the 1,3,4-oxadiazole ring, showed mixed inhibition in the absence of DTT. Incubation of these compounds with Cryptococcus IMPDH followed by mass spectrometry analysis showed non-specific and covalent binding with IMPDH at multiple cysteine residues. These results support recent reports that the benzo[b]thiophene 1,1-dioxides moiety as PAINS (pan-assay interference compounds) contributor.

Glutathione-PEGylated liposomal methylprednisolone in comparison to free methylprednisolone: slow release characteristics and prolonged lymphocyte depression in a first-in-human study

AIMS

Intravenous high-dose free methylprednisolone (MP) hemisuccinate is the primary treatment for an acute relapse in relapsing-remitting multiple sclerosis. However, it is inconvenient and its side effects are undesirable. Both dose and dosing frequency can be reduced by incorporating free MP in glutathione-PEGylated liposomes, creating a slow-release formulation with reduced toxicity and prolonged peripheral efficacy. This first-in-human study was designed to assess the safety, pharmacokinetics and pharmacodynamics of glutathione-PEGylated liposomes containing MP (2B3-201).

METHODS

The first part was a double-blind, three-way cross over study in 18 healthy male subjects, receiving ascending doses of 2B3-201, active comparator (free MP) or placebo. Part 2 of the study was an open-label infusion of 2B3-201 (different doses), exploring pretreatment with antihistamines and different infusion schedules in another 18 healthy male subjects, and a cross-over study in six healthy female subjects. MP plasma concentrations, lymphocyte counts, adrenocorticotropic hormone, osteocalcin and fasting glucose were determined. Safety and tolerability profiles were assessed based on adverse events, safety measurements and central nervous system tests.

RESULTS

The most frequent recorded AE related to 2B3-201 was an infusion related reaction (89%). 2B3-201 was shown to have a plasma half-life between 24 and 37 h and caused a prolonged decrease in the lymphocyte count, adrenocorticotropic hormone and osteocalcin, and a rise in fasting glucose.

CONCLUSION

2B3-201 is considered safe, with no clinically relevant changes in central nervous system safety parameters and no serious adverse events. In addition, 2B3-201 shows a long plasma half-life and prolonged immunosuppressive effects.

Pharmacokinetics of antifungal drugs: practical implications for optimized treatment of patients

Introduction

Because of the high mortality of invasive fungal infections (IFIs), appropriate exposure to antifungals appears to be crucial for therapeutic efficacy and safety.

Materials and methods

This review summarises published pharmacokinetic data on systemically administered antifungals focusing on co-morbidities, target-site penetration, and combination antifungal therapy.

Conclusions and discussion

Amphotericin B is eliminated unchanged via urine and faeces. Flucytosine and fluconazole display low protein binding and are eliminated by the kidney. Itraconazole, voriconazole, posaconazole and isavuconazole are metabolised in the liver. Azoles are substrates and inhibitors of cytochrome P450 (CYP) isoenzymes and are therefore involved in numerous drug–drug interactions. Anidulafungin is spontaneously degraded in the plasma. Caspofungin and micafungin undergo enzymatic metabolism in the liver, which is independent of CYP. Although several drug–drug interactions occur during caspofungin and micafungin treatment, echinocandins display a lower potential for drug–drug interactions. Flucytosine and azoles penetrate into most of relevant tissues. Amphotericin B accumulates in the liver and in the spleen. Its concentrations in lung and kidney are intermediate and relatively low myocardium and brain. Tissue distribution of echinocandins is similar to that of amphotericin. Combination antifungal therapy is established for cryptococcosis but controversial in other IFIs such as invasive aspergillosis and mucormycosis.

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

The safety, tolerability, and pharmacokinetics of the liposomal formulation of amphotericin B (L-AMB) were evaluated in 40 immunocompromised children and adolescents. The protocol was an open-label, sequential-dose-escalation, multidose pharmacokinetic study with 10 to 13 patients in each of the four dosage cohorts. Each cohort received daily dosages of 2.5, 5.0, 7.5, or 10 mg of amphotericin B in the form of L-AMB per kg of body weight. Neutropenic patients between the ages of 1 and 17 years were enrolled to receive empirical antifungal therapy or treatment of documented invasive fungal infections. The pharmacokinetic parameters of L-AMB were measured as those of amphotericin B by high-performance liquid chromatography and calculated by noncompartmental methods. There were nine adverse-event-related discontinuations, four of which were related to infusions. Infusion-related side effects occurred for 63 (11%) of 565 infusions, with 5 patients experiencing acute infusion-related reactions (7.5- and 10-mg/kg dosage levels). Serum creatinine levels increased from 0.45 ± 0.04 mg/dl to 0.63 ± 0.06 mg/dl in the overall population (P = 0.003), with significant increases in dosage cohorts receiving 5.0 and 10 mg/kg/day. At the higher dosage level of 10 mg/kg, there was a trend toward greater hypokalemia and vomiting. The area under the concentration-time curve from 0 to 24 h (AUC_0-24) values for L-AMB on day 1 increased from 54.7 ± 32.9 to 430 ± 566 μg · h/ml in patients receiving 2.5 and 10.0 mg/kg/day, respectively. These findings demonstrate that L-AMB can be administered to pediatric patients at dosages similar to those for adults and that azotemia may develop, especially in those receiving ≥5.0 mg/kg/day.

Liposomal Amphotericin B (AmBisome(®)): A Review of the Pharmacokinetics, Pharmacodynamics, Clinical Experience and Future Directions

Liposomal amphotericin B (AmBisome(®); LAmB) is a unique lipid formulation of amphotericin B. LAmB is a standard of care for a wide range of medically important opportunistic fungal pathogens. LAmB has a significantly improved toxicity profile compared with conventional amphotericin B deoxycholate (DAmB). Despite nearly 20 years of clinical use, the pharmacokinetics and pharmacodynamics of this agent, which differ considerably from DAmB, remain relatively poorly understood and underutilized in the clinical setting. The molecular pharmacology, preclinical and clinical pharmacokinetics, and clinical experience with LAmB for the most commonly encountered fungal pathogens are reviewed. In vitro, experimental animal models and human clinical trial data are summarized, and novel routes of administration and dosing schedules are discussed. LAmB is a formulation that results in reduced toxicity as compared with DAmB while retaining the antifungal effect of the active agent. Its long terminal half-life and retention in tissues suggest that single or intermittent dosing regimens are feasible, and these should be actively investigated in both preclinical models and in clinical trials. Significant gaps remain in knowledge of pharmacokinetics and pharmacodynamics in special populations such as neonates and children, pregnant women and obese patients.

Diagnosis and Treatment of Leishmaniasis: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH)

It is important to realize that leishmaniasis guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. The IDSA and ASTMH consider adherence to these guidelines to be voluntary, with the ultimate determinations regarding their application to be made by the physician in the light of each patient's individual circumstances.

Management of rhinomaxillary mucormycosis with Posaconazole in immunocompetent patients

Mucormycosis is an opportunistic, uncommon and serious systemic fungal infection mostly presenting in immunocompromised patients. The combination of surgical debridement, parenteral therapy with Amphotericin B and management of the underlying systemic disease is the standard treatment modality for mucormycosis. The drawback of this regime is the need for long hospitalization due to the serious side effects of Amphotericin B requiring regular monitoring. Oral Posaconazole is one of the newer antifungals that have shown promising results. This paper highlights a case series of rhinomaxillary mucormycosis in immunocompetent patients diagnosed and managed successfully with surgical debridement and oral Posaconazole administration on out-patient basis.

Practice Guidelines for the Diagnosis and Management of Aspergillosis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Safety and efficacy of treatment with liposomal amphotericin B in elderly patients at least 65 years old with hematological diseases

The safety and efficacy of treatment with liposomal amphotericin B (L-AMB) in elderly patients has not been clarified, especially in Japanese patients. Therefore, we retrospectively analyzed 33 elderly patients with hematological diseases of at least 65 years old who received L-AMB between 2009 and 2012. Their clinical outcomes were compared to those of 21 patients who were younger than 65 years. L-AMB was administered for empirical therapy (n = 2) or target therapy for possible (n = 14) or probable/proven (n = 17) invasive fungal infection. There was no discontinuation of L-AMB due to adverse events. More than 2-fold increases from the baseline Cre, AST, and ALT values were observed in 21.2%, 39.4%, and 45.5% of the older group and 38.1%, 61.9%, and 52.4% of the younger group, respectively. The concurrent use of nephrotoxic antibiotics was the only risk factor for the development of a 2-fold increase in the serum Cre level. The duration of L-AMB was significantly longer in patients who developed grade III-IV hypokalemia. A partial or complete response was observed in 54.8% and 62.5% of the elderly and younger groups, respectively. In conclusion, L-AMB therapy appeared to be acceptably safe as empirical therapy or treatment for invasive fungal infection.

Efficacy and safety of micafungin for the prophylaxis of invasive fungal infection during neutropenia in children and adolescents undergoing allogeneic hematopoietic SCT

The objective of this study was to evaluate the efficacy and safety of micafungin for the prevention of invasive fungal infection (IFI) during the neutropenic phase of allogeneic hematopoietic SCT (allo-HSCT) in children and adolescents. This was a prospective, multicenter, open-label, single-arm study. Micafungin was administered i.v. at a dose of 1 mg/kg/day (max 50 mg) from the beginning of conditioning until neutrophil engraftment. Treatment success was defined as the absence of proven, probable, possible or suspected IFI through to 4 weeks after therapy. From April 2010 to December 2011, 155 patients were enrolled from 11 institutions in Korea, and 147 patients were analyzed. Of the 147 patients, 121 (82.3%) completed the protocol without premature interruption. Of the 132 patients in whom micafungin efficacy could be evaluated, treatment success was achieved in 119 patients (90.2%). There was no proven fungal infection in any patient. The number of patients with probable, possible and suspected IFI was two, two and nine, respectively. Thirty-five patients (23.8%) experienced 109 adverse events (AEs) possibly related to micafungin. No patients experienced grade IV AEs. Two patients (1.4%) discontinued micafungin administration due to adverse effects. None of the deaths were related to the study drug.

PRTX-100 and methotrexate in patients with active rheumatoid arthritis: A Phase Ib randomized, double-blind, placebo-controlled, dose-escalation study

PRTX-100 is a highly-purified preparation of staphylococcal protein A (SpA), with immunologic activity in vitro and in animal models of immune-mediated inflammation. Following single-dose healthy volunteer studies of safety and pharmacokinetics (PK), a multicenter, double-blind, placebo-controlled, sequential dose-escalation, repeated-dose phase I trial was conducted in patients with active rheumatoid arthritis (RA) on methotrexate therapy. Patients were randomized to receive either weekly intravenous PRTX-100 (0.15, 0.45, 0.90, or 1.50 µg/kg) or placebo for 4 weeks. Safety and disease activity were assessed over 16 weeks. Pharmacokinetic profiles were obtained after the first and fourth doses. The most common treatment-related adverse events were nausea, muscle spasms, dizziness, flushing, fatigue, RA flare, and headache. No serious adverse events were considered related to PRTX-100, and none occurred in the highest dose group. Geometric mean values for plasma Cmax (ng/mL) were 4.1, 15.7, 26.5, and 51.2 for doses of 0.15, 0.45, 0.90, and 1.5 µg/kg, respectively. Anti-drug antibodies (ADAs) developed in most PRTX-100 patients, but incidence and titer were not dose-dependent. At the two highest doses, data suggest PRTX-100 may have an effect on RA disease activity, even in patients with ADAs.

Renal retention of lipid microbubbles: a potential mechanism for flank discomfort during ultrasound contrast administration

BACKGROUND

The etiology of flank pain sometimes experienced during the administration of ultrasound contrast agents is unknown. The aim of this study was to investigate whether microbubble ultrasound contrast agents are retained within the renal microcirculation, which could lead to either flow disturbance or local release of vasoactive and pain mediators downstream from complement activation.

METHODS

Retention of lipid-shelled microbubbles in the renal microcirculation of mice was assessed by confocal fluorescent microscopy and contrast-enhanced ultrasound imaging with dose-escalating intravenous injection. Studies were performed with size-segregated microbubbles to investigate physical entrapment, after glycocalyx degradation and in wild-type and C3-deficient mice to investigate complement-mediated retention. Urinary bradykinin was measured before and after microbubble administrations. Renal contrast-enhanced ultrasound in human subjects (n = 13) was performed 7 to 10 min after the completion of lipid microbubble administration.

RESULTS

In both mice and humans, microbubble retention was detected in the renal cortex by persistent contrast-enhanced ultrasound signal enhancement. Microbubble retention in mice was linearly related to dose and occurred almost exclusively in cortical glomerular microvessels. Microbubble retention did not affect microsphere-derived renal blood flow. Microbubble retention was not influenced by glycocalyx degradation or by microbubble size, thereby excluding lodging, but was reduced by 90% (P < .01) in C3-deficient mice. Urinary bradykinin increased by 65% 5 min after microbubble injection.

CONCLUSIONS

Lipid-shelled microbubbles are retained in the renal cortex because of complement-mediated interactions with glomerular microvascular endothelium. Microbubble retention does not adversely affect renal perfusion but does generate complement-related intermediates that are known to mediate nociception and could be responsible for flank pain.

Invasive fungal infections in acute leukemia

Invasive fungal infection (IFI) is among the leading causes for morbidity, mortality, and economic burden for patients with acute leukemia. In the past few decades, the incidence of IFI has increased dramatically. The certainty of diagnosis of IFI is based on host factors, clinical evidence, and microbiological examination. Advancement in molecular diagnostic modalities (e.g. non-culture-based serum biomarkers such as β-glucan or galactomannan assays) and high-resolution radiological imaging has improved our diagnostic approach. The early use of these diagnostic tests assists in the early initiation of preemptive therapy. Nonetheless, the complexity of IFI in patients with leukemia and the limitations of these diagnostic tools still mandate astute clinical acumen. Its management has been further complicated by the increasing frequency of infection by non-Aspergillus molds (e.g. zygomycosis) and the emergence of drug-resistant fungal pathogens. In addition, even though the antifungal armamentarium has expanded rapidly in the past few decades, the associated mortality remains high. The decision to initiate antifungal treatment and the choice of anti-fungal therapy requires careful consideration of several factors (e.g. risk stratification, local fungal epidemiologic patterns, concomitant comorbidities, drug-drug interactions, prior history of antifungal use, overall cost, and the pharmacologic profile of the antifungal agents). In order to optimize our diagnostic and therapeutic management of IFI in patients with acute leukemia, further basic research and clinical trials are desperately needed.

Risk factors of amphotericin B toxicty in the nonneonatal pediatric population

BACKGROUND

Amphotericin B (AmB) traditionally has been the mainstay of therapy for children with candidemia but is associated with drug-related toxicities (DRT). Studies investigating the risk factors for AmB DRT in children are limited.

METHODS

A retrospective review of patients aged 6 months to ≤18 years with candidemia who received ≥1 dose of AmB from 2003 to 2009 was conducted at Texas Children's Hospital, Houston, TX. Patient demographics, risk factors, drug dosages, laboratory adverse effects and infusion-related side effects (INFRT) were recorded.

RESULTS

A total of 223 episodes of candidemia occurred in 179 patients. AmB was administered in 172 (77%) episodes. Amphotericin B deoxycholate, Amphotericin B lipid complex and liposomal Amphotericin B were administered in 65 (38%), 96 (55%) and 11 (6.4%) episodes, respectively. When the first episode of AmB use was analyzed separately (n = 138), DRT occurred in 83% (n = 114); nephrotoxicity occurred in 45% (n = 62), hypokalemia in 47% (n = 62) and INFRT in 31 % (n = 41). The most common INFRT was chills and rigors (80%, n = 33) followed by fever (31.7%, n = 13) and hypotension (9.7%, n = 4). Patients with lower baseline creatinine clearance were at increased risk of having nephrotoxicity than those with higher baseline creatinine clearance (P = 0.004). Nephrotoxicity was less likely in patients who received immunosuppressants (P = 0.02). Neutropenia (P = 0.02) and prior hypokalemia (P = 0.001) were independently associated with hypokalemia. The receipt of premedication was independently associated with a lower likelihood of INFRT (P ≤ 0.0001). It is important to note that most AmB-related DRT was quickly reversible.

CONCLUSIONS

AmB-associated DRT was common and reversible in our nonneonatal pediatric population. Prospective studies are required to further evaluate risk factors and determine whether they are modifiable.

Caspofungin as antifungal prophylaxis in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation: a retrospective analysis

Background

Pediatric patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) often receive intravenous liposomal amphotericin B (L-AmB) as antifungal prophylaxis. There are no guidelines for antifungal prophylaxis in children in this situation. Caspofungin (CAS), a broad-spectrum echinocandin, could be an effective alternative with lower nephrotoxicity than L-AmB.

Methods

We retrospectively analyzed the safety, feasibility, and efficacy of CAS in our center, and compared the results with L-AmB as antifungal monoprophylaxis in pediatric patients undergoing HSCT. 60 pediatric patients received L-AmB (1 or 3 mg/kg bw/day) and another 60 patients received CAS (50 mg/m²/day) as antifungal monoprophylaxis starting on day one after HSCT. The median ages of patients receiving L-AmB and CAS were 7.5 years and 9.5 years, respectively.

Results

No proven breakthrough fungal infection occurred in either group during the median treatment period of 23 days in the L-AmB group and 24 days in the CAS group. One patient receiving CAS developed probable invasive aspergillosis. During L-AmB treatment, potassium levels significantly decreased below normal values. Patients treated with L-AmB had more drug-related side effects and an increased need for oral supplementation with potassium, sodium bicarbonate and calcium upon discharge as compared with the CAS group. CAS was well-tolerated and safe in this cohort of immunocompromised pediatric patients, who underwent high-dose chemotherapy and HSCT.

Conclusion

Prophylactic CAS and L-AmB showed similar efficacy in this biggest cohort of pediatric patients after allogeneic HSCT reported, so far. A prospective randomized trial in children is warranted to allow for standardized guidelines.

An evaluation of hepatotoxicity and nephrotoxicity of liposomal amphotericin B (L-AMB)

Hepatic and renal functions are important considerations when selecting antifungal therapy. This investigation of liposomal amphotericin B (L-AMB) was conducted to determine the incidence and factors associated with the development of hepatotoxicity and nephrotoxicity. A retrospective chart review was conducted of 100 consecutive patients receiving L-AMB at doses of 1, 3, and 5 mg/kg. Hepatotoxicity was defined as an increase of bilirubin greater than 1.5 mg/dl or AST and ALT greater than three times the normal range. Nephrotoxicity was defined as an increase in serum creatinine of 0.5 mg/dl or an increase of 50% from baseline. Patients were included if they were 18 years of age or older. Patients were excluded if they had developed hepatic or renal dysfunction prior to L-AMB administration. Seventy-five patients were included based upon the predefined inclusion/exclusion criteria. Twenty-one percent (16/75) developed hepatotoxicity based upon the predefined criteria. There were no additive correlates for this adverse effect. Overall, 56% (42/75) of patients developed nephrotoxicity. Seventy-four percent (31/42) were exposed to IV contrast, and 90% (38/42) were receiving nephrotoxins concurrently. Age, cumulative dose, concomitant nephrotoxins, and IV contrast exposure were associated with increased nephrotoxicity (p<0.001). The development of hepatotoxicity was observed; however, no correlates (age, dose escalation, or cumulative dose) were significantly associated with its occurrence. Overall nephrotoxicity with L-AMB was common and often multifactorial. Lipid amphotericin B products are associated with lower rates of nephrotoxicity than conventional amphotericin; however, in this analysis, L-AMB was associated with a high incidence of nephrotoxicity.

Lipsosomal amphotericin B for treatment of cutaneous leishmaniasis

Treatment options for cutaneous leishmaniasis in the United States are problematic because the available products are either investigational, toxic, and/or of questionable effectiveness. A retrospective review of patients receiving liposomal amphotericin B through the Walter Reed Army Medical Center for the treatment of cutaneous leishmaniasis during 2007-2009 was conducted. Twenty patients who acquired disease in five countries and with five different strains of Leishmania were treated, of whom 19 received a full course of treatment. Sixteen (84%) of 19 experienced a cure with the initial treatment regimen. Three patients did not fully heal after an initial treatment course, but were cured with additional dosing. Acute infusion-related reactions occurred in 25% and mild renal toxicity occurred in 45% of patients. Although the optimum dosing regimen is undefined and the cost and toxicity may limit widespread use, liposomal amphotericin B is a viable treatment alternative for cutaneous leishmaniasis.