Do variations in molecular structure affect the clinical efficacy and safety of lipid-based amphotericin B preparations?

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

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

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.

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

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

Nanoparticles as safe and effective delivery systems of antifungal agents: Achievements and challenges

Invasive fungal infections are becoming a major health concern in several groups of patients leading to severe morbidity and mortality. Moreover, cutaneous fungal infections are a major cause of visits to outpatient dermatology clinics. Despite the availability of several effective agents in the antifungal drug arena, their therapeutic outcome is less than optimal due to limitations related to drug physicochemical properties and toxicity. For instance, poor aqueous solubility limits the formulation options and efficacy of several azole antifungal drugs while toxicity limits the benefits of many other drugs. Nanoparticles hold great promise to overcome these limitations due to their ability to enhance drug aqueous solubility, bioavailability and antifungal efficacy. Further, drug incorporation into nanoparticles could greatly reduce its toxicity. Despite these interesting nanoparticle features, there are only few marketed nanoparticle-based antifungal drug formulations. This review sheds light on different classes of nanoparticles used in antifungal drug delivery, such as lipid-based vesicles, polymeric micelles, solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and dendrimers with emphasis on their advantages and limitations. Translation of these nanoformulations from the lab to the clinic could be facilitated by focusing the research on overcoming problems related to nanoparticle stability, drug loading and high cost of production and standardization.

Nanopharmaceuticals (part 1): products on the market

In 2000, the National Institute of Health launched the National Nanotechnology Initiative to support, coordinate, and advance research and development of nanoscale projects. The impact of this new program on health-science related research and development became quickly visible. Broad governmental financial support advanced the start of new, and the deepening of already existing, interdisciplinary research. The anticipated merger of nanoscience with medicine quickly instigated the conceptualization of nanomedicine. The adoption of nanoscience terminology by pharmaceutical scientists resulted in the advent of nanopharmaceuticals. The term "nano" became tantamount to "cutting-edge" and was quickly embraced by the pharmaceutical science community. Colloidal drug delivery systems reemerged as nanodrug delivery systems; colloidal gold became a suspension of nano gold particles. In this review, we first review nanoscience related definitions applied to pharmaceuticals, we then discuss all 43 currently approved drug formulations which are publicized as nanopharmaceuticals, and finally we analyze clinical aspects of selected drug formulations.

Amphotericin B formulations: a comparative review of efficacy and toxicity

Because of the increasing prevalence and changing microbiological spectrum of invasive fungal infections, some form of amphotericin B still provides the most reliable and broad spectrum therapeutic alternative. However, the use of amphotericin B deoxycholate is accompanied by dose-limited toxicities, most importantly, infusion-related reactions and nephrotoxicity. In an attempt to improve the therapeutic index of amphotericin B, three lipid-associated formulations were developed, including amphotericin B lipid complex (ABLC), liposomal amphotericin B (L-AmB), and amphotericin B colloidal dispersion (ABCD). The lipid composition of all three of these preparations differs considerably and contributes to substantially different pharmacokinetic parameters. ABLC is the largest of the lipid preparations. Because of its size, it is taken up rapidly by macrophages and becomes sequestered in tissues of the mononuclear phagocyte system such as the liver and spleen. Consequently, compared with the conventional formulation, it has lower circulating amphotericin B serum concentrations, reflected in a marked increase in volume of distribution and clearance. Lung levels are considerably higher than those achieved with other lipid-associated preparations. The recommended therapeutic dose of ABLC is 5 mg/kg/day. Because of its small size and negative charge, L-AmB avoids substantial recognition and uptake by the mononuclear phagocyte system. Therefore, a single dose of L-AmB results in a much higher peak plasma level (Cmax) than conventional amphotericin B deoxycholate and a much larger area under the concentration-time curve. Tissue concentrations in patients receiving L-AmB tend to be highest in the liver and spleen and much lower in kidneys and lung. Recommended therapeutic dosages are 3-6 mg/kg/day. After intravenous infusion, ABCD complexes remain largely intact and are rapidly removed from the circulation by cells of the macrophage phagocyte system. On a milligram-to-milligram basis, the Cmax achieved is lower than that attained by conventional amphotericin B, although the larger doses of ABCD that are administered produce an absolute level that is similar to amphotericin B. ABCD exhibits dose-limiting, infusion-related toxicities; consequently, the administered dosages should not exceed 3-4 mg/kg/day. The few comparative clinical trials that have been completed with the lipid-associated formulations have not demonstrated important clinical differences among these agents and amphotericin B for efficacy, although there are significant safety benefits of the lipid products. Furthermore, only one published trial has ever compared one lipid product against another for any indication. The results of these trials are particularly difficult to interpret because of major heterogeneities in study design, disease definitions, drug dosages, differences in clinical and microbiological endpoints as well as specific outcomes examined. Nevertheless, it is possible to derive some general conclusions given the available data. The most commonly studied syndrome has been empiric therapy for febrile neutropenic patients, where the lipid-associated preparations did not appear to provide a survival benefit over conventional amphotericin B deoxycholate, but did offer a significant advantage for the prevention of various breakthrough invasive fungal infections. For treatment of documented invasive fungal infections that usually involved hematological malignancy patients, no individual randomized trial has demonstrated a mortality benefit due to therapy with one of the lipid formulations. Results from meta-analyses have been contradictory, with one demonstrating a mortality benefit from all-cause mortality and one that did not demonstrate a mortality benefit. In the only published study to examine HIV-infected patients with disseminated histoplasmosis, clinical success and mortality were significantly better with L-AmB compared with amphotericin B deoxycholate; there were no differences in microbiological outcomes between treatment groups. The lipid-associated preparations were not significantly better than amphotericin B deoxycholate for treatment of AIDS-associated acute cryptococcal meningitis for either clinical or microbiological outcomes that were studied. In all of the trials that specifically examined renal toxicity, the lipid-associated formulations were significantly less nephrotoxic than amphotericin B deoxycholate. Infusion-related reactions occurred less frequently with L-AmB when compared with amphotericin B deoxycholate; however, ABCD had equivalent or more frequent infusion-related reactions than conventional amphotericin B, and this resulted in the cessation of at least one clinical trial. At the present time, this particular lipid formulation is no longer commercially available. For the treatment of most invasive fungal infections, an amphotericin B lipid formulation provides a safer alternative than conventional amphotericin B, with at least equivalent efficacy. As the cost of therapy with these agents continues to decline, these drugs will likely maintain their important role in the antifungal drug armamentarium because of their efficacy and improved safety profile.

Amphotericin B Formulations and Drug Targeting

Amphotericin B is a low-soluble polyene antibiotic which is able to self-aggregate. The aggregation state can modify its activity and pharmacokinetical characteristics. In spite of its high toxicity it is still widely employed for the treatment of systemic fungal infections and parasitic disease and different formulations are marketed. Some of these formulations, such as liposomal formulations, can be considered as classical examples of drug targeting. The pharmacokinetics, toxicity and activity are clearly dependent on the type of amphotericin B formulation. New drug delivery systems such as liposomes, nanospheres and microspheres can result in higher concentrations of AMB in the liver and spleen, but lower concentrations in kidney and lungs, so decreasing its toxicity. Moreover, the administration of these drug delivery systems can enhance the drug accessibility to organs and tissues (e.g., bone marrow) otherwise inaccessible to the free drug. During the last few years, new AMB formulations (AmBisome, Abelcet, and Amphotec) with an improved efficacy/toxicity ratio have been marketed. This review compares the different formulations of amphotericin B in terms of pharmacokinetics, toxicity and activity and discusses the possible drug targeting effect of some of these new formulations.

Secretion of proinflammatory cytokines and chemokines during amphotericin B exposure is mediated by coactivation of toll-like receptors 1 and 2

Amphotericin B (AmB) is a ligand of toll-like receptor 2 (TLR2). Here, we demonstrate the participation of TLR1 in AmB-induced cell activation that led to the secretion of tumor necrosis factor alpha, interleukin 6 (IL-6), and IL-8. Hence, TLR2-TLR1 coactivation serves as the underlying mechanism for the proinflammatory toxicities associated with AmB.

Efficacies of Amphotericin B (AMB) Lipid Complex, AMB Colloidal Dispersion, Liposomal AMB, and Conventional AMB in Treatment of Murine Coccidioidomycosis

The therapeutic efficacy of three lipid formulations of amphotericin B was compared with that of conventional amphotericin B in treatment of murine coccidioidomycosis. All treatments prolonged survival compared with the no-treatment group ( P < 0.0001). Although conventional amphotericin B was more active than lipid formulations on reducing quantitative fungal load on a milligram-per-kilogram basis ( P < 0.003 to 0.0002), the lipid preparations could be administered at higher doses, sterilizing liver and spleen tissues. The efficacies of the lipid preparations were similar in this murine model of coccidioidomycosis.

Efficacy, safety and cost-effectiveness of Amphotericin B Lipid Complex (ABLC): a review of the literature

Amphotericin B Lipid Complex (ABLC) was the first lipid-based formulation of amphotericin B (AmB) to be developed, it was designed to provide a less toxic alternative to conventional AmB without compromising efficacy. Preclinical and early clinical data relating to ABLC have been presented in previous reviews. This paper reviews more recent published data on the efficacy, safety and cost-effectiveness of ABLC. All published manuscripts and conference abstracts were searched on MEDLINE, BIOL and SCIN for the period between January 1997 and August 2003. Comparative and non-comparative studies of ABLC are usually mild or moderate and are manageable were considered. Comparative studies and additional data from non-comparative studies suggest that ABLC 5 mg/kg/day is safe and effective for the treatment of documented or suspected systemic fungal infections in adults and children who are refractory to or intolerant of conventional AmB. ABLC is effective against a wide range of pathogens and efficacy is at least as good as conventional AmB or the other lipid-based formulations. The safety profile of ABLC is improved compared with conventional AmB; ABLC is less nephrotoxic than conventional AmB and can be given safely to patients with pre-existing renal impairment. The most commonly reported adverse effects are transient infusion-related events, including chills, fever, nausea and vomiting, which with premedication. Comparative studies suggest that ABLC is a cost-effective treatment option compared with conventional AmB or other lipid-based formulations of amphotericin B.

Invasive aspergillosis in liver transplant recipients: outcome comparison of therapy with amphotericin B lipid complex and a historical cohort treated with conventional amphotericin B

Invasive aspergillosis (IA) in liver transplant recipients is associated with poor response rates and a very high mortality rate, despite administration of therapy with conventional amphotericin B. We conducted a single-center, retrospective study to compare the outcome of liver transplant recipients with IA who received amphotericin B lipid complex (ABLC) or conventional amphotericin B. IA was present in 12 ABLC-treated patients (definite, 4; probable, 8) and 29 amphotericin B recipients (definite, 11; probable, 18) in the historical cohort. The 60-day mortality rate was lower in the ABLC cohort: 4 (33%) of 12 patients versus 24 (83%) of 29 patients (P=.006). Only 1 of 4 ABLC recipients with definite IA died, compared with all 11 in the amphotericin B group. Sixty-day survival probability curves was significantly lower in the amphotericin B cohort (P=.008). ABLC therapy was the only independent mortality-protective variable (odds ratio, 0.31; 95% confidence interval, 0.07-0.44; P=.02). First-line or early salvage therapy for IA with ABLC was associated with significantly improved survival relative to a comparable historical group treated with amphotericin B.

A systematic review of the antifungal effectiveness and tolerability of amphotericin B formulations

OBJECTIVE

A systematic review was performed to compare the effectiveness and tolerability of lipid-based amphotericin B (AmB) formulations and conventional AmB in the treatment of systemic fungal infections.

METHODS

The literature and unpublished studies were searched using MEDLINE, EMBASE, Biological Abstracts, AIDSLINE, CANCERLIT, CRD database, Cochrane Controlled Trials Register, and other databases. Search terms included: amphotericin, liposom*, lipid*, colloid*, antifungal agents, and mycoses. Studies were selected according to predetermined criteria. The outcome measures reviewed were efficacy, mortality, renal toxicity, and infusion-related reactions. Meta-analyses and number-needed-to-treat (NNT) analyses were performed.

RESULTS

Seven studies (8 publications) met the entry criteria. Meta-analysis showed that lipid-based formulations significantly reduced all-cause mortality risk by an estimated 28% compared with conventional AmB (odds ratio [OR], 0.72; 95% CI, 0.54 to 0.97). There was no significant difference in efficacy between the lipid-based formulations and conventional AmB (OR, 1.21; 95% CI, 0.98 to 1.49). AmB lipid complex (ABLC) and liposomal AmB (L-AmB) significantly reduced the risk of doubling serum creatinine by an estimated 58% (OR, 0.42; 95% CI, 0.33 to 0.54). There was no significant reduction in risk of infusion-related reactions with lipid-based formulations, although this was difficult to interpret given the lack of consistent control of confounding factors. Comparing the lipid-based formulations with conventional AmB, the overall NNT to prevent 1 death was 31. The NNT to prevent a doubling of serum creatinine for both ABLC and L-AmB compared with conventional AmB was 6.

CONCLUSIONS

This study demonstrates advantages with lipid-based formulations over conventional AmB in terms of reduced risk of mortality and renal toxicity. Future trials in patients with proven fungal infection should control for factors such as premedication, infusion rates, fluid preloading, sodium/potassium supplementation, and concomitant medication.

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.

Practice guidelines for lipid-based amphotericin B in stem cell transplant recipients

OBJECTIVE

To provide clinicians who practice in the stem cell transplantation (SCT) setting with practical guidelines for the use of lipid-based amphotericin B (AmB) formulations in SCT patients who have documented or probable invasive fungal infections, are experiencing neutropenic fever, or require secondary prophylaxis for fungal infections.

DATA SOURCES

Recommendations are based on the results of a two-day consensus meeting that convened clinicians versed in the management of infectious complications in patients undergoing SCT. This meeting, which was held October 21-23, 1998, in Orlando, Florida, was sponsored by an educational grant from The Liposome Company. In addition, primary articles were identified by MEDLINE search (1980-December 1999) and through secondary sources.

STUDY SELECTION AND DATA EXTRACTION

All of the articles identified from the data sources were evaluated, and all information deemed relevant was included in this review.

DATA SYNTHESIS

Immunocompromised patients, particularly patients undergoing high-dose chemotherapy with SCT, experience a high degree of morbidity and mortality from invasive fungal infections. Historically, treatment for such infections with conventional AmB had been limited primarily by its associated nephrotoxicity. Lipid-based formulations of AmB have helped to advance the management of invasive fungal infections in the SCT population by offering a treatment alternative that allows for administration of adequate amounts of active drug to produce clinical and mycologic responses, compared with conventional AmB, in a delivery system that is less nephrotoxic. Unfortunately, these agents are relatively expensive. Therefore, patients who are candidates for lipid-based products must be selected carefully.

CONCLUSIONS

Practical guidelines are provided for the use of lipid-based AmB formulations in SCT patients who have documented or probable invasive fungal infections, are experiencing neutropenic fever, or require secondary prophylaxis for fungal infections.

Amphotericin B preparations: a maximum tolerated dose in severe invasive fungal infections?

Availability of lipid formulations of amphotericin B has opened up the possibility of treating invasive fungal infections in immunocompromised patients with high doses of this antifungal agent. Evidence is emerging to suggest that lipid formulations may have heightened efficacy compared to conventional amphotericin B. The issue of optimal dosage has been a neglected area. This article reviews published data accrued from clinical, open-label, salvage, and other studies, and finds little support that the use of high doses of lipid formulations are more efficacious than lower doses. The response rates for invasive fungal infection from most studies are predictably around 56%, irrespective of the lipid formulation and dose used. Animal models provide evidence that low doses of a lipid formulation are as successful in reducing fungal dissemination and in prolonging survival as higher doses, although concomitant tissue fungal eradication is not as effectively achieved by the lower doses (survival-mycologic eradication dissociation). Kinetic studies performed in the clinically relevant setting of critically ill patients give further support to the use of low doses, since levels of liposomal amphotericin B at all dosages between 1 and 4 mg/kg/day are similar and above maximum inhibitory concentrations for commonly encountered fungi. There has only been one prospective randomised study designed with the primary end-point of comparing two dosages of an amphotericin B lipid formulation on clinical response and survival. That European Organization for Research and Treatment of Cancer (EORTC) study concluded that liposomal amphotericin B given at 1 mg was as efficacious as 4 mg/kg/day in treating neutropenic patients with invasive pulmonary aspergillosis. There are a multitude of unanswered questions concerning dosing, and their answers are confounded by difficulties in performing clinical trials and the multiplicity of factors other than antifungal chemotherapy that influence outcome. Maximum tolerated dose studies using existing lipid formulations, or perhaps with the newer formulations such as pegylated immunoliposomal amphotericin B, could be performed to shed light on this difficult area.

Amphotericin B colloidal dispersion (Amphocil) vs fluconazole for the prevention of fungal infections in neutropenic patients: data of a prematurely stopped clinical trial

We conducted an open label, randomised clinical trial to compare amphotericin B colloidal dispersion (ABCD, Amphocil) 2 mg/kg/day intravenously with fluconazole 200 mg/day orally, for the prevention of fungal disease in neutropenic patients with haematological malignancies. In the event of unresolved fever after 4 days of empirical antibacterial therapy, patients in both treatment groups were to receive ABCD, 4 mg/kg/day. However, the study had to be stopped in an early phase, due to severe side-effects of ABCD. A total of 24 patients were enrolled, 12 patients were randomly assigned to receive prophylactic ABCD, which was administered for a mean of 13.9 days. Fluconazole prophylaxis was given to 12 patients for a mean of 21.2 days. Therapeutic ABCD, 4 mg/kg, was initiated in four patients because of suspected fungal infection, all of whom had initially received fluconazole. A high rate of infusion-related toxicity of ABCD was observed. Chills occurred in 15/16 ABCD recipients (94%), accompanied by a temperature rise of >/=2 degrees C in 4/16 patients and of >/=1 degrees C but <2 degrees C in 10/16 patients. Other ABCD-related adverse events were hypotension (4/16), nausea with vomiting (5/16), tachycardia (7/16), headache (3/16) and dyspnoea (3/16). For premedication patients received: antihistamines (12/16), hydrocortisone (9/16) and/or morphine (6/16). ABCD was discontinued in 8/16 patients (50%) due to side-effects, which ultimately dictated early termination of the study. We conclude that ABCD is not suitable for antifungal prophylaxis in neutropenic patients due to severe infusion-related side-effects. Subject numbers were too low for conclusions on variables of antifungal efficacy.

A comparative analysis of lipid-complexed and liposomal amphotericin B preparations in haematological oncology

No comparative clinical information on the properties of lipid-associated amphotericin preparations is presently available. In this single-centre retrospective analysis over a 5-year period the indications, efficacy and toxicity of true liposomal amphotericin (AmBisome) were compared with a lipid complexed preparation (Abelcet). In a novel approach APACHE III scores were used in addition to neutrophil counts, disease status and additional immunosuppression to accurately assess the severity of illness in both groups and enable valid comparison. Overall, AmBisome at a median dose of 1.9 mg/kg/d was found to have similar clinical outcome to Abelcet at a median dose of 4.8 mg/kg/d. Nephrotoxicity and electrolyte abnormalities were similar in both groups. Rigors and febrile episodes were more common with Abelcet. Prospective randomized comparative trials are required to clarify the optimum dosages and therapeutic and economic issues associated with these agents.