Amphotericin B Lipid Complex (Abelcet) in the treatment of invasive mycoses: the North American experience

Nanomaterials in Drug Delivery: Strengths and Opportunities in Medicine

There is a myriad of diseases that plague the world ranging from infectious, cancer and other chronic diseases with varying interventions. However, the dynamism of causative agents of infectious diseases and incessant mutations accompanying other forms of chronic diseases like cancer, have worsened the treatment outcomes. These factors often lead to treatment failure via different drug resistance mechanisms. More so, the cost of developing newer drugs is huge. This underscores the need for a paradigm shift in the drug delivery approach in order to achieve desired treatment outcomes. There is intensified research in nanomedicine, which has shown promises in improving the therapeutic outcome of drugs at preclinical stages with increased efficacy and reduced toxicity. Regardless of the huge benefits of nanotechnology in drug delivery, challenges such as regulatory approval, scalability, cost implication and potential toxicity must be addressed via streamlining of regulatory hurdles and increased research funding. In conclusion, the idea of nanotechnology in drug delivery holds immense promise for optimizing therapeutic outcomes. This work presents opportunities to revolutionize treatment strategies, providing expert opinions on translating the huge amount of research in nanomedicine into clinical benefits for patients with resistant infections and cancer.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

An Overview of Nanomaterial Applications in Pharmacology

Nanotechnology has become one of the most extensive fields of research. Nanoparticles (NPs) form the base for nanotechnology. Recently, nanomaterials (NMs) are widely used due to flexible chemical, biological, and physical characteristics with improved efficacy in comparison to bulk counterparts. The significance of each class of NMs is enhanced by identifying their properties. Day by day, there is an emergence of various applications of NMs, but the toxic effects associated with them cannot be avoided. NMs demonstrate therapeutic abilities by enhancing the drug delivery system, diagnosis, and therapeutic effects of numerous agents, but determining the benefits of NMs over other clinical applications (disease-specific) or substances is an ongoing investigation. This review is aimed at defining NMs and NPs and their types, synthesis, and pharmaceutical, biomedical, and clinical applications.

Nanomedicine and nanoparticle-based delivery systems in plastic and reconstructive surgery

BACKGROUND

Nanotechnology and nanomedicine are rising novel fields in plastic and reconstructive surgery (PRS). The use of nanomaterials often goes with regenerative medicine. Due to their nanoscale, these materials stimulate repair at the cellular and molecular levels. Nanomaterials may be placed as components of nanocomposite polymers allowing enhancement of overall biochemical and biomechanical properties with improved scaffold properties, cellular attachment, and tissue regeneration. They may also be formulated as nanoparticle-based delivery systems for controlled release of signal factors or antimicrobials, for example. However, more studies on nanoparticle-based delivery systems still need to be done in this field. Nanomaterials are also used as frameworks for nerves, tendons, and other soft tissues.

MAIN BODY

In this mini-review, we focus on nanoparticle-based delivery systems and nanoparticles targeting cells for response and regeneration in PRS. Specifically, we investigate their roles in various tissue regeneration, skin and wound healing, and infection control. Cell surface-targeted, controlled-release, and inorganic nanoparticle formulations with inherent biological properties have enabled enhanced wound healing, tumor visualization/imaging, tissue viability, and decreased infection, and graft/transplantation rejection through immunosuppression.

CONCLUSIONS

Nanomedicine is also now being applied with electronics, theranostics, and advanced bioengineering technologies. Overall, it is a promising field that can improve patient clinical outcomes in PRS.

Review of Novel Oral Amphotericin B Formulations for the Treatment of Parasitic Infections

Amphotericin B (AmpB) is a polyene macrolide antibiotic used in the treatment of blood-borne parasitic and fungal infections. However, its use, particularly in the developing world, has been limited by dose-dependent kidney toxicity, other systemic-related toxicity issues following injection, the inconvenience of parenteral administration, and accessibility. Oral formulation approaches have focused on the dual problem of solubility and permeability of AmpB, which is poorly water soluble, amphoteric and has extremely low oral bioavailability. Therefore, to enhance oral absorption, researchers have employed micellar formulations, polymeric nanoparticles, cochleates, pro-drugs, and self-emulsifying drug delivery systems (SEDDS). This paper will highlight current uses of AmpB against parasitic infections such as leishmaniasis, preclinical and clinical formulation strategies, applications in veterinary medicine and the importance of developing a cost-effective and safe oral AmpB formulation.

Development of Pharmaceutical Nanomedicines: From the Bench to the Market

Nanotechnology plays a significant role in the field of medicine and in drug delivery, mainly due to the major limitations affecting the conventional pharmaceutical agents, and older formulations and delivery systems. The effect of nanotechnology on healthcare is already being felt, as various nanotechnology applications have been developed, and several nanotechnology-based medicines are now on the market. Across many parts of the world, nanotechnology draws increasing investment from public authorities and the private sector. Most conventional drug-delivery systems (CDDSs) have an immediate, high drug release after administration, leading to increased administration frequency. Thus, many studies have been carried out worldwide focusing on the development of pharmaceutical nanomedicines for translation into products manufactured by local pharmaceutical companies. Pharmaceutical nanomedicine products are projected to play a major role in the global pharmaceutical market and healthcare system. Our objectives were to examine the nanomedicines approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) in the global market, to briefly cover the challenges faced during their development, and to look at future perspectives. Additionally, the importance of nanotechnology in developing pharmaceutical products, the ideal properties of nanocarriers, the reasons behind the failure of some nanomedicines, and the important considerations in the development of nanomedicines will be discussed in brief.

A brief overview about the use of different bioactive liposome-based drug delivery systems in Peritoneal Dialysis and some other diseases

Peritoneal dialysis (PD) is a promising way of treatment used for patients suffering from End-Stage Renal Failure (ESRF). Liposomes are nanocarriers comprised of lipid bilayers encapsulating an aqueous core. Liposomes are extensively used as drug delivery systems and several liposomal nanomedicines have been approved for clinical applications. Nanomedicine constitutes a new direction in peritonitis prevention using peritoneal dialysis (PD). In case of PD; there is a more risk of bacterial infection in the peritoneal cavity along with subcutaneous tunnel and catheter existing site. These infections are the most common complications associated with prolonged peritoneal dialysis (PD) therapy. To prevent such complications, patients used to treat with suitable antibiotic. Nanocarriers consist of assembly of nano-sized vehicles planned to deliver encapsulated/loaded bioactive(s) to the specific target (tissues or organs) and have provided prominent improved therapeutic efficacy for PD patients. The advantage of bioactive loaded nanocarrier has the efficient capacity to deliver at target specific site in PD. This review focuses mainly on the current use of different liposomal encapsulated bioactive compounds in drug delivery systems in the case of PD and other human diseases and briefly highlights the importance and use of different liposomal encapsulated antimicrobial agents to improve the PD technique.

Assessing the Safety, Tolerability, Pharmacokinetics, and Biodistribution of Novel Oral Formulations of Amphotericin B following Single- and Multiple-Dose Administration to Beagle Dogs

The purpose of this study was to assess the safety, tolerability, pharmacokinetics (PK), and biodistribution of novel oral amphotericin B (AmpB) formulations following single- and multiple-oral-dose administration to healthy beagle dogs. The liquid formulation of AmpB was administered to three male dogs, and the capsule formulations of AmpB were administered to each of two groups of six male dogs. Blood was collected for pharmacokinetic evaluation on days 1, 2, and 3 (up to 72 h postdosing). Dogs receiving the capsule formulations further received a single oral dose of 100 mg once daily for three more days, and on the 4th day, blood samples were taken at 24 h postdosing and the dogs were humanely sacrificed with the removal of organs, from which tissue samples were taken for analysis of the AmpB content. Multiple-dose studies were completed for 7 or 14 days with daily doses of up to 1,000 mg/day with the capsule formulations. All oral formulations of AmpB following both single- and multiple-dose administration were well tolerated in the dogs, and there were no relevant adverse signs observed, such as changes in hematologic, coagulation, or biochemistry parameters; loss of weight; changes in food or water intake; or signs of gastrointestinal distress. The oral absorption of AmpB from the liquid formulation and the capsule formulations were similar, with no significant differences. The tissue distributions of AmpB were similar following repeated doses of the two capsule formulations to dogs. Following 14 days of treatment with the iCo-010 liquid formulation and the iCo-019 and iCo-022 capsule formulations, the range of values of the maximum observed plasma concentration (C _max) was 53.2 to 62.3, 24.9 to 66.4, and 36.7 to 85.2 ng/ml, respectively; the range of values of the time to C _max was 4 to 12, 4 to 24, and 2 to 24 h, respectively; and the range of values of the area under the plasma concentration-time curve from time zero to the time of the last quantifiable concentration was 2,635 to 3,071, 1,053 to 2,517, and 1,443 to 3,713 ng · h/ml, respectively. We have developed a safe novel oral AmpB formulation suitable for future efficacy studies.

The Development of Oral Amphotericin B to Treat Systemic Fungal and Parasitic Infections: Has the Myth Been Finally Realized?

Parenteral amphotericin B has been considered as first-line therapy in the treatment of systemic fungal and parasitic infections, however its use has been associated with a number of limitations including affordability, accessibility, and an array of systemic toxicities. Until very recently, it has been very challenging to develop a bioavailable formulation of amphotericin B due to its physical chemical properties, limited water and lipid solubility, and poor absorption. This perspective reviews several novel oral Amphotericin B formulations under development that are attempting to overcome these limitations.

The Multirole of Liposomes in Therapy and Prevention of Infectious Diseases

Liposomes are closed bilayer structures spontaneously formed by hydrated phospholipids that are widely used as efficient delivery systems for drugs or antigens, due to their capability to encapsulate bioactive hydrophilic, amphipathic, and lipophilic molecules into inner water phase or within lipid leaflets. The efficacy of liposomes as drug or antigen carriers has been improved in the last years to ameliorate pharmacokinetics and capacity to release their cargo in selected target organs or cells. Moreover, different formulations and variations in liposome composition have been often proposed to include immunostimulatory molecules, ligands for specific receptors, or stimuli responsive compounds. Intriguingly, independent research has unveiled the capacity of several phospholipids to play critical roles as intracellular messengers in modulating both innate and adaptive immune responses through various mechanisms, including (i) activation of different antimicrobial enzymatic pathways, (ii) driving the fusion–fission events between endosomes with direct consequences to phagosome maturation and/or to antigen presentation pathway, and (iii) modulation of the inflammatory response. These features can be exploited by including selected bioactive phospholipids in the bilayer scaffold of liposomes. This would represent an important step forward since drug or antigen carrying liposomes could be engineered to simultaneously activate different signal transduction pathways and target specific cells or tissues to induce antigen-specific T and/or B cell response. This lipid-based host-directed strategy can provide a focused antimicrobial innate and adaptive immune response against specific pathogens and offer a novel prophylactic or therapeutic option against chronic, recurrent, or drug-resistant infections.

Liposomal Formulations in Clinical Use: An Updated Review

Liposomes are the first nano drug delivery systems that have been successfully translated into real-time clinical applications. These closed bilayer phospholipid vesicles have witnessed many technical advances in recent years since their first development in 1965. Delivery of therapeutics by liposomes alters their biodistribution profile, which further enhances the therapeutic index of various drugs. Extensive research is being carried out using these nano drug delivery systems in diverse areas including the delivery of anti-cancer, anti-fungal, anti-inflammatory drugs and therapeutic genes. The significant contribution of liposomes as drug delivery systems in the healthcare sector is known by many clinical products, e.g., Doxil®, Ambisome®, DepoDur™, etc. This review provides a detailed update on liposomal technologies e.g., DepoFoam™ Technology, Stealth technology, etc., the formulation aspects of clinically used products and ongoing clinical trials on liposomes.

Establishment of correlation between in-silico and in-vitro test analysis against Leishmania HGPRT to inhibitors

Hypoxanthine Phosphoribosyltransferase (HGPRT; EC 2.4.2.8) is a central enzyme in the purine recycling pathway of all protozoan parasites. Protozoan parasites cannot synthesize purine bases (DNA/RNA) which is essential for survival as lack of de-novo pathway. Thus its good target for drug design and discovery as inhibition leads to cessation of replication. PRTase (transferase enzyme) has common PRTase type I folding pattern domain for its activities. Genomic studies revealed the sequence pattern and identified highly conserved residues that catalyzed the reaction in protozoan parasites. A recombinant protein has 24 kDa molecular mass (rLdHGPRT) was cloned, expressed and purified for testing of guanosine monophosphate (GMP) analogous compounds in-vitro by spectroscopically to the rLdHGPRT, lysates protein and MTT assay on Leishmania donovani. The predicted inhibitors of different libraries were screen into FlexX. The reported inhibitors were tested in-vitro. The 2'-deoxyguanosine 5'-diphosphate (DGD) (IC50 value 12.5 μM) is two times more effective when compared to guanosine-5'-diphosphate sodium (GD). Interestingly, LdHGPRT complex has shown stable after 24 ns in molecular dynamics simulation with interacting amino acids are Glu125, Ile127, Lys87 and Val186. QSAR studies revealed the correlation between predicted and experimental values has shown R2 0.998. Concludes that inversely proportional to their docked score with activities.

Adverse effects of antifungal therapies in invasive fungal infections: review and meta-analysis

Amphotericin B is the main therapeutic agent for the treatment of invasive fungal infections; however, it is associated with significant toxicities that limit its use. Other systemic antifungal agents have been developed to improve tolerability while maintaining the efficacy profile of conventional amphotericin B. Fifty-four studies involving 9,228 patients were assessed for the frequency of adverse effects of the main systemic antifungal agents. While the results suggest that liposomal amphotericin B is the least nephrotoxic of the lipid formulations (14.6%), that conventional amphotericin B is the most nephrotoxic (33.2%), and that itraconazole is the most hepatotoxic (31.5%), the lack of standard definitions of antifungal-related adverse effects limits the validity of these results. Furthermore, heterogeneous patient pools and differing protocols make it difficult to draw direct comparisons between studies. With the advent of newer classes of systemic antifungal agents, future trials should conform to definitions that are universally applicable and clinically relevant to allow for such comparisons and to enable evidence-based decision-making.

Adverse effects of antifungal therapies in invasive fungal infections: review and meta-analysis

Amphotericin B is the main therapeutic agent for the treatment of invasive fungal infections; however, it is associated with significant toxicities that limit its use. Other systemic antifungal agents have been developed to improve tolerability while maintaining the efficacy profile of conventional amphotericin B. Fifty-four studies involving 9,228 patients were assessed for the frequency of adverse effects of the main systemic antifungal agents. While the results suggest that liposomal amphotericin B (L-AmB) is the least nephrotoxic of the lipid formulations (14.6%), that conventional amphotericin B (AmB) is the most nephrotoxic (33.2%), and that itraconazole is the most hepatotoxic (31.5%), the lack of standard definitions of antifungal-related adverse effects limits the validity of these results. Furthermore, heterogeneous patient pools and differing protocols make it difficult to draw direct comparisons between studies. With the advent of newer classes of systemic antifungal agents, future trials should conform to definitions that are universally applicable and clinically relevant to allow for such comparisons and to enable evidence-based decision-making.

Comparative efficacies of four amphotericin B formulations--Fungizone, amphotec (Amphocil), AmBisome, and Abelcet--against systemic murine aspergillosis

We compared various amphotericin B formulations (no treatment or 0.8 mg of Fungizone [conventional deoxycholate amphotericin B] per kg of body weight, or 0.8, 4, or 8 mg of Amphocil, AmBisome, or Abelcet per kg of body weight) for treatment of systemic murine aspergillosis. In two studies, all formulations prolonged survival, with the results for AmBisome nearly equivalent to those for Fungizone; Amphocil and Abelcet were less effective or equivalent depending on the severity of infection. No survivors were cured in both kidneys and brain, but each formulation showed efficacy, especially in the kidneys. Although higher doses could be given, no lipid-based formulation showed consistent superiority over Fungizone or over each other.

Eradication of severe neonatal systemic candidiasis with amphotericin B lipid complex

OBJECTIVE

To report the successful use of amphotericin B lipid complex in treating severe systemic candidiasis in a very-low-birth-weight infant.

CASE SUMMARY

A preterm female infant, born at 25 weeks' gestational age with a birth weight of 870 g, had received full supportive care in the neonatal intensive care unit (NICU), including mechanical ventilation, total parenteral nutrition, and placement of central venous catheters. At seven weeks of age, she developed severe disseminated candidiasis, which failed to respond to conventional amphotericin B and fluconazole therapy. Her progressive deterioration was reversed only after amphotericin B lipid complex (A-complex) was substituted for conventional amphotericin B. The improvement in her condition was impressive, and she made a full recovery without any adverse effect.

DISCUSSION

With increased reliance on invasive technologies for life support, systemic candida infections have become increasingly common among premature infants in the NICU. Such infections are potentially fatal for the high-risk neonate. A literature review shows limited documentation of the use of lipid-based formulations of amphotericin B, especially A-complex, in preterm infants. However, the collective experience with these products appears to show that they are effective and cause fewer adverse effects than conventional amphotericin B. The infant reported here had shown progressive deterioration from disseminated candidiasis until conventional amphotericin B therapy was replaced with A-complex. Her recovery corresponded to the clearance of the candidemia.

CONCLUSIONS

With favorable results and increasing experience with lipid-based formulations of amphotericin B, it is reasonable to consider these new formulations as therapy for candidemia in preterm infants who are at a high risk of nephrotoxicity or who have failed conventional therapy.

Retrospective analysis of the dosage of amphotericin B lipid complex for the treatment of invasive fungal infections

STUDY OBJECTIVE

To understand the relationship between dosage and therapeutic response of amphotericin B lipid complex (ABLC) by analyzing underlying diseases, types of infections, and therapeutic outcomes with different dosages as second-line antifungal therapy.

DESIGN

Retrospective analysis of low-dose (initial dose < or = 3 mg/kg) ABLC from three open-label, clinical, second-line treatment studies.

SETTING

Centers in the United States (204), Canada (3), Australia (1), Mexico (1), and The Netherlands (1).

PATIENTS

Five hundred fifty-one patients (5 enrolled twice) with invasive fungal infections, of whom 289 failed and 267 were intolerant to conventional antifungal therapy.

INTERVENTIONS

Patients were to receive the recommended dosage of ABLC 5 mg/kg/day, with dosage reduction for markedly increased serum creatinine. The duration of treatment was 4 weeks; therapy could be extended if the investigator considered additional treatment necessary.

MEASUREMENTS AND MAIN RESULTS

Seventy-three patients (13%) received ABLC 3 mg/kg/day (low dosage) instead of the protocol-recommended 5 mg/kg/day Response was 65% and 56%, respectively. Logistic regression analysis revealed that the following patients are most likely to start therapy at the lower dosage: those with candidiasis and other yeast infections, patients with nephrotoxicity due to prior amphotericin B, and those with underlying conditions other than hematologic malignancy.

CONCLUSION

These results suggest that ABLC 3 mg/kg/day may be effective in treating patients with candidiasis who do not have hematologic malignancy.

A comparative review of conventional and lipid formulations of amphotericin B

Over the past 15 years, factors suh as corticosteroid treatment, cytotoxic chemotherapy, excessive use of broad spectrum antibiotics and HIV have led to an increased risk of serious fungal infections in both adults and pediatric patients. This increase in invasive fungal infections poses increasing difficulty in their treatment. Three new lipid formulations of amphotericin B are now available in the U.S.: amphotericin B lipid complex (Abelcet), amphotericin B colloidal dispersion (Amphotec), and liposomal amphotericin B (AmBisome). These newer formulations are substantially more expensive, but allow patients to receive higher doses for longer periods of time with decreased renal toxicity than conventional amphotericin B. The properties of these new agents are summarized in this review. Discussion of current national guidelines as well as those used at our institution are presented to provide guidance for the development of institution specific guidelines for the most cost-effective drug for most patients, some may benefit more from one of the newer lipid formulations.

Emerging fungal pathogens, drug resistance and the role of lipid formulations of amphotericin B in the treatment of fungal infections in cancer patients: a review

The incidence of life-threatening invasive fungal infections in immunocompromised patients has increased dramatically in recent years. Candida spp other than C. albicans are increasingly being isolated, and Aspergillus infections also are on the increase, as well as infections due to previously uncommon organisms. It is likely that this phenomenon is multifactorial in origin, although the extensive use of antifungal prophylaxis may have played a role, especially for the emergence of non-albicans Candida. Amphotericin B remains the antifungal agent with the broadest spectrum of action available and is thus the standard treatment for immunocompromised patients with proven or suspected fungal infections, especially aspergillosis. However, its potential for nephrotoxicity limits its usefulness. Lipid formulations of amphotericin B may allow therapy to be administered with reduced renal toxicity. Three different lipid formulations of amphotericin B currently are available. These compounds have different pharmacokinetic properties and seem to achieve higher serum or tissue concentrations than amphotericin B. This statement is based on animal models and scattered human data. At present, there are no studies comparing the lipid formulations with each other and only a few randomized trials comparing them with conventional amphotericin B. However, a number of open clinical trials and compassionate-use protocols suggest that lipid-based forms of amphotericin B can achieve good response rates with minimal toxicity in patients with a variety of invasive mycoses, including those who have proved refractory or intolerant to previous therapy with conventional amphotericin B. Unfortunately, the cost of these compounds remains high and may represent a limiting factor to their use.

In vitro activity of Syn-2869, a novel triazole agent, against emerging and less common mold pathogens

The in vitro activity of Syn-2869 was compared with that of amphotericin B and itraconazole. MICs for 100 isolates of pathogenic molds belonging to 12 species were determined by a broth microdilution adaptation of the method recommended by the National Committee for Clinical Laboratory Standards. Syn-2869 and itraconazole showed comparable, good activity against the dematiaceous molds Cladophialophora bantiana, Cladophialophora carrionii, Exophiala dermatitidis, Fonsecaea pedrosoi, Phialophora parasitica, and Ramichloridium mackenziei. Neither of the azole agents was active against the hyaline molds Fusarium solani, Scedosporium prolificans, and Scopulariopsis brevicaulis, but both were more active than amphotericin B against Scedosporium apiospermum. The MICs of the three agents were comparable for the mucoraceous mold Absidia corymbifera, but Syn-2869 appeared to be the least active against the dimorphic mold Sporothrix schenckii. Our results suggest that Syn-2869 could be effective against a range of mold infections in humans.

Aspergillus fumigatus and aspergillosis

Aspergillus fumigatus is one of the most ubiquitous of the airborne saprophytic fungi. Humans and animals constantly inhale numerous conidia of this fungus. The conidia are normally eliminated in the immunocompetent host by innate immune mechanisms, and aspergilloma and allergic bronchopulmonary aspergillosis, uncommon clinical syndromes, are the only infections observed in such hosts. Thus, A. fumigatus was considered for years to be a weak pathogen. With increases in the number of immunosuppressed patients, however, there has been a dramatic increase in severe and usually fatal invasive aspergillosis, now the most common mold infection worldwide. In this review, the focus is on the biology of A. fumigatus and the diseases it causes. Included are discussions of (i) genomic and molecular characterization of the organism, (ii) clinical and laboratory methods available for the diagnosis of aspergillosis in immunocompetent and immunocompromised hosts, (iii) identification of host and fungal factors that play a role in the establishment of the fungus in vivo, and (iv) problems associated with antifungal therapy.

An EORTC multicentre prospective survey of invasive aspergillosis in haematological patients: diagnosis and therapeutic outcome. EORTC Invasive Fungal Infections Cooperative Group

OBJECTIVES

The EORTC Invasive Fungal Infections Cooperative Group (IFICG) conducted a prospective survey by questionnaire of all cases of invasive aspergillosis (IA) in cancer patients to ascertain current diagnostic and therapeutic approaches.

METHODS

All members of the IFICG were asked prospectively to complete a detailed questionnaire for each IA case identified in their institution over a 12-month period.

RESULTS

One hundred and thirty questionnaires were returned. All cases were independently evaluated (DWD & JC) and 123 were eligible. Cases came from 20 hospitals in eight countries and the number of cases per institution varied from 1-21. Acute myeloid leukaemia (AML) (60, 49%), acute lymphoblastic leukaemia (ALL) (21, 17%) and lymphoma (11, 9%) were the most frequent underlying diseases, and 16 (12%) patients had received an allogeneic bone marrow transplant. Pulmonary involvement was present in 87%, infection of sinuses/nose in 16% and brain in 8%. The chest radiograph was initially normal in 9% of those with primary pulmonary disease. The diagnosis was confirmed in 50%, probable in 31% and possible in 19%. The evidence for IA was on the basis of clinical and radiological features alone in 28%, with culture or histology in another 31% and 9%, respectively, and with both culture and histology in 29%. In three (2%) patients with diagnosis was based on culture or histology alone. Treatment was given to 120 patients (98%)-amphotericin B 75%, lipid-associated amphotericin B 36%, itraconazole 40%, flucytosine 12%, growth factors 33%, lobectomy 5%. At 3 months after diagnosis or first suspicion of IA, 44 (36%) patients were alive and 79 (64%) dead. Outcome was best in those with AML (30% death and 46% with a complete antifungal response or cure). Growth factors (mostly granulocyte colony stimulating factor) appeared not to influence outcome (P = 0.99).

CONCLUSION

IA remains a considerable diagnostic and therapeutic challenge. No single diagnostic procedure was universally successful and a multifaceted approach including surgery is necessary. There was no discernable difference in outcome between initial therapy with amphotericin B, itraconazole or lipid-associated amphotericin B, although numbers are limited and the study was retrospective.

Comparison of fungizone, Amphotec, AmBisome, and Abelcet for treatment of systemic murine cryptococcosis

Three lipid-based formulations of amphotericin B have been approved for use in various countries. The aim of this study was to compare Amphotec (ABCD; Sequus), AmBisome (AmBi; Nexstar), Abelcet (ABLC; The Liposome Co.), and conventional deoxycholate amphotericin B (Fungizone; Bristol Meyers Squibb) for the treatment of experimental systemic cryptococcosis. A model was established in 10-week-old female CD-1 mice by intravenous (i.v.) injection of 6.25 x 10(5) viable Cryptococcus neoformans yeast cells. Therapy began 4 days later, with i.v. administration three times per week for 2 weeks. Mice received either no treatment, 1 mg of Fungizone per kg of body weight, or 1, 5, or 10 mg of ABCD, AmBi, or ABLC per kg. Ninety percent of control mice died between days 15 and 34. All treatment regimens except ABLC at 1 mg/kg prolonged survival compared with no treatment (P < 0.01 to 0.001). All mice receiving 5 or 10 mg of ABCD or AmBi per kg and 90% of mice given 10 mg of ABLC per kg survived, whereas < or =50% of those given other treatment regimens survived. Fungizone was the least effective of the four formulations, with 5 or 10 mg of ABCD, AmBi, or ABLC per kg resulting in a significantly better outcome than Fungizone (P < 0.001). Among the three formulations, ABCD and AmBi were equally effective, both being better than ABLC at equal 5- or 10-mg/kg doses (P < 0.001). Comparison of residual infectious burdens in various organs showed that each drug had some dose-responsive efficacy in three or more organs at escalating doses. In the brain, ABCD or AmBi at 5 or 10 mg/kg or ABLC at 10 mg/kg was more effective than Fungizone at 1 mg/kg or no treatment, while ABCD or AmBi at 1 mg/kg was as effective as ABLC at 10 mg/kg. Similar results were obtained for the kidneys and lungs. In the spleen, ABCD at 10 mg/kg cured all mice of infection and was superior to all other regimens. In the liver, AmBi at 5 mg/kg was superior to an equal dose of ABCD or ABLC. Overall, the efficacies of ABCD and AmBi were equal to that of Fungizone at 1 mg/kg and were about 10-fold better than that of ABLC, particularly in the brain; a comparative rank order of efficacies was ABCD approximately equal to AmBi > ABLC >> Fungizone. This is the first study that compared all four amphotericin B formulations.

Lack of utility of the lysis-centrifugation blood culture method for detection of fungemia in immunocompromised cancer patients

We retrospectively compared the utility of a fungal isolation device (Isolator) versus conventional techniques for recovering fungal organisms from blood cultures obtained from neutropenic cancer patients. Positive cultures were deemed true pathogens, possible pathogens, or contaminants according to laboratory and clinical criteria. Fifty-three patients had 66 positive blood cultures for fungi, nine on multiple occasions. In 20 episodes true pathogens were recovered, 6 from broth medium alone, 4 from the Isolator system alone, and 10 from both systems. False-negative cultures were noted in 4 of 20 (20%) cases in which broth medium was used and in 6 of 20 (30%) cases in which the Isolator system was used. Possible pathogens were detected in 4 of 66 blood culture-positive cases. Forty-two positive cultures were considered contaminants, 1 collected from standard medium and 41 of 42 (98%) which grew only in Isolators. Eleven of 18 patients with true fungal infections expired as a result of infection, while 4 of 33 patients with a contaminant expired, none from a fungal cause. We do not advocate the routine use of Isolator tubes in the evaluation of the febrile, neutropenic patient due to the high rates of false positives and of contamination.

Amphotericin B lipid complex

OBJECTIVE

To evaluate the published data on the effectiveness and safety of amphotericin B lipid complex (ABLC) for the treatment of invasive mycosis and to evaluate data describing the pharmacologic properties and pharmacokinetic behavior of ABLC in both animals and humans.

DATA SOURCE

A MEDLINE search was conducted to identify literature published from 1965 to January 1997 for amphotericin B deoxycholate (DCAB) and ABLC. In addition, preliminary data published as abstracts and presented at national conferences on infectious disease and hematology within the last 6 years were also included in this review.

STUDY SELECTION

Both human and animal studies were reviewed. Animal and in vitro studies were selected to evaluate the pharmacologic and toxicologic properties of ABLC. For the evaluation of the efficacy, safety, and pharmacokinetic behavior of ABLC, large, well-controlled studies were reviewed. In addition, data from open-label and emergency use protocols were also included in the review.

DATA EXTRACTION

The study and analytical methods, results, and conclusions of the selected studies were evaluated. Pharmacokinetic data for both ABLC and DCAB that were derived from human subjects were also evaluated.

DATA SYNTHESIS

DCAB has been the cornerstone for the treatment of invasive mycosis, even though it has a narrow therapeutic index. Infusion-related toxicities (e.g., fever, chills, rigors) are likely due to DCAB stimulation of cytokine and prostaglandin synthesis. Conversely, nephrotoxicity, the primary non-infusion-related toxicity, likely results from the nonselective cytotoxic interaction between DCAB and cholesterol-containing mammalian cells. ABLC represents a new approach to improving the therapeutic index of DCAB. Mammalian cytotoxicity is attenuated by complexing amphotericin B to a mixture of phospholipids. This alters the affinity of amphotericin B and decreases its selective transfer from the complex to cholesterol-containing mammalian cells. Fungi also possess lipase, which improves the selective transfer from the complex to ergosterol-containing cell membranes. In humans, the lipid formulation increases the volume of distribution of amphotericin B. Thus, compared with DCAB, larger doses of ABLC can be administered for a longer duration with less nephrotoxicity. However, the prevalence of infusion-related toxicities associated with ABLC is similar to that of DCAB. Whether the alteration in distribution improves efficacy by improving tissue concentrations of amphotericin B has not been determined. The cost of this agent will limit its use.

CONCLUSIONS

ABLC has been shown to be at least as effective as DCAB, and it has been well tolerated in the clinical studies to date. Despite large dosages and extended courses of administration, there is little nephrotoxicity associated with its use. However, the cost of this agent will limit its use to the treatment of refractory mycosis or to cases where DCAB is contraindicated due to significant renal insufficiency.