Amphotericin B lipid soluble formulations versus amphotericin B in cancer patients with neutropenia

Polyene Antibiotics Physical Chemistry and Their Effect on Lipid Membranes; Impacting Biological Processes and Medical Applications

This review examined a collection of studies regarding the molecular properties of some polyene antibiotic molecules as well as their properties in solution and in particular environmental conditions. We also looked into the proposed mechanism of action of polyenes, where membrane properties play a crucial role. Given the interest in polyene antibiotics as therapeutic agents, we looked into alternative ways of reducing their collateral toxicity, including semi-synthesis of derivatives and new formulations. We follow with studies on the role of membrane structure and, finally, recent developments regarding the most important clinical applications of these compounds.

Incorporation of Nonyl 3,4-Dihydroxybenzoate Into Nanostructured Lipid Systems: Effective Alternative for Maintaining Anti-Dermatophytic and Antibiofilm Activities and Reducing Toxicity at High Concentrations

Dermatophytosis is the most common mycosis worldwide, affecting approximately 20 to 25% of the population, regardless of gender, race, color, and age. Most antifungal agents used for the treatment of dermatophytosis belong to the azole and allylamine classes. Dermatophytes are reported to be resistant to most commercial drugs, especially microbial biofilms, in addition to their considerable toxicity. It should be emphasized the importance of looking for new molecules with reduced toxicity, as well as new targets and mechanisms of action. This work aims to incorporate nonyl 3,4-dihydroxybenzoate, a potent fungicide compound against planktonic cells and dermatophyte biofilms in nanostructured lipid systems (NLS), in order to reduce toxicity in high concentrations, improve its solubility and maintain its effectiveness. The compound was incorporated into NLS constituted by cholesterol, mixture of polyoxyethylene (23) lauryl ether (Brij^®98) and soybean phosphatidylcholine (Epikuron^® 200)], 2: 1 ratio and PBS (phosphate-buffered saline). The characterization of the incorporation was performed. Susceptibility tests were conducted according to document M38-A2 by CLSI (2008). The toxicity of the NLS compound was evaluated in HaCaT cell lines by the sulforhodamine B method and in alternative models Caenorhabditis elegans and zebrafish. Finally, its efficacy was evaluated against the mature Trichophyton rubrum and Trichophyton mentagrophytes biofilms. NLS and nonyl 3,4-dihydroxybenzoate loaded into NLS displayed sizes ranging from 137.8 ± 1.815 to 167.9 ± 4.070 nm; the polydispersity index (PDI) varying from 0.331 ± 0.020 to 0.377 ± 0.004 and zeta potential ranging from −1.46 ± 0.157 to −4.63 ± 0.398 mV, respectively. Polarized light microscopy results confirmed the formation of NLS of the microemulsion type. Nonyl incorporated into NLS showed minimum inhibitory concentration (MIC) values, ranging from 2 to 15.6 mg/L. The toxicity tests presented cell viability higher than 80% in all tested concentrations, as well as, a significantly increased of the survival of Caenorhabditis elegans and zebrafish models. Anti-biofilm tests proved the efficacy of the incorporation. These findings contribute significantly to the search for new antifungals and allow the systemic administration of the compound, since the incorporation can increase the solubility of non-polar compounds, improve bioavailability, effectiveness and reduce toxicity.

Adverse effects of amphotericin B in children; a retrospective comparison of conventional and liposomal formulations

AIMS

Lipid formulations of amphotericin B, rather than conventional amphotericin (c-amB), are increasingly used despite limited data comparing these preparations in children. Data on the incidence of adverse effects with amphotericin B at standard doses are scarce. This study aimed to compare the adverse effects associated with standard doses of c-amB and liposomal amphotericin (l-amB) in children.

METHODS

Children admitted to the Royal Children's Hospital Melbourne and treated with c-amB or l-amB between January 2010 and September 2013 were included. Clinical and laboratory data were retrospectively extracted from medical records to compare amphotericin-related infusion reactions, nephrotoxicity (glomerulotoxicity and tubulopathy) and hepatotoxicity.

RESULTS

Seventy-six children received c-amB and 39 received l-amB. Standard drug administration (recommended dose and infusion time) occurred in 74% (56/76) of patients on c-amB and 85% (33/39) on l-amB. In these 89 children, infusion-related reactions were similar for both c-amB and l-amB (23% (13/56) vs. 9% (3/33); P = 0.15); none occurred in children aged <90 days. There was no difference in amphotericin-associated glomerulotoxicity (c-amB 14% (8/56) vs. l-amB 21% (7/33); P = 0.40) or in the median maximum potassium requirements (c-amB 3.1 vs. l-amB 2.3 mmol kg^-1  d^-1 ; P = 0.29). Hepatotoxicity occurred more frequently with l-amB than c-amB (83% (24/29) vs. 56% (20/36); P = 0.032).

CONCLUSIONS

When appropriately administered, l-amB was associated with more hepatotoxicity than c-amB, with no difference in infusion-related reactions or nephrotoxicity. Differences in adverse effects between the preparations is not as marked in children as reported in adults.

Nanomedicinal products: a survey on specific toxicity and side effects

Due to their specific properties and pharmacokinetics, nanomedicinal products (NMPs) may present different toxicity and side effects compared to non-nanoformulated, conventional medicines. To facilitate the safety assessment of NMPs, we aimed to gain insight into toxic effects specific for NMPs by systematically analyzing the available toxicity data on approved NMPs in the European Union. In addition, by comparing five sets of products with the same active pharmaceutical ingredient (API) in a conventional formulation versus a nanoformulation, we aimed to identify any side effects specific for the nano aspect of NMPs. The objective was to investigate whether specific toxicity could be related to certain structural types of NMPs and whether a nanoformulation of an API altered the nature of side effects of the product in humans compared to a conventional formulation. The survey of toxicity data did not reveal nanospecific toxicity that could be related to certain types of structures of NMPs, other than those reported previously in relation to accumulation of iron nanoparticles (NPs). However, given the limited data for some of the product groups or toxicological end points in the analysis, conclusions with regard to (a lack of) potential nanomedicine-specific effects need to be considered carefully. Results from the comparison of side effects of five sets of drugs (mainly liposomes and/or cytostatics) confirmed the induction of pseudo-allergic responses associated with specific NMPs in the literature, in addition to the side effects common to both nanoformulations and regular formulations, eg, with liposomal doxorubicin, and possibly liposomal daunorubicin. Based on the available data, immunotoxicological effects of certain NMPs cannot be excluded, and we conclude that this end point requires further attention.

Amphotericin B deoxycholate versus liposomal amphotericin B: effects on kidney function

BACKGROUND

The incidence of invasive fungal infections has increased globally as a result of several factors. Conventional amphotericin B (sodium deoxycholate) has been used as standard therapy for the treatment of invasive fungal infections; however, it is associated with adverse drug reactions, including acute kidney injury (AKI). New formulations of amphotericin B have aimed to improve the safety profile of the conventional formulation.

OBJECTIVES

This review aimed to assess the effects of amphotericin B deoxycholate versus liposomal amphotericin B on kidney function.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 10 March 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared amphotericin B sodium deoxycholate with liposomal amphotericin B.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for eligibility and conducted risk of bias evaluation.

MAIN RESULTS

We included 12 studies (2298 participants) in this review. Of these, 10 were meta-analysed (2172 participants). Liposomal amphotericin B was found to be significantly safer than conventional amphotericin B in terms of serum creatinine increase (RR 0.49, 95% CI 0.40 to 0.59). There was significant decrease in all infusion-related reactions in the liposomal group compared with the conventional group: fever (4 studies, 1092 participants): RR 0.39, 95% CI 0.28 to 0.55; I(2) = 32%); chills and/or rigours (5 studies, 1081 participants): RR 0.27, 95% CI 0.15 to 0.48; I(2) = 75%); fever and/or rigours (2 studies, 720 participants): RR 0.68, 95% CI 0.52 to 0.90; I(2) = 58%); nausea (6 studies, 1187 participants): RR 0.50, 95% CI 0.35 to 0.72; I(2) = 0%); and vomiting (3 studies, 1019 participants): RR 0.51, 95% CI 0.27 to 0.95; I(2) = 61%). Overall, risk of bias in included studies was low or unclear for most domains. However, blinding of participants and personnel, blinding of outcome assessment and other bias (funding) tended to have a high risk of bias. The sensitivity analysis performed did not change the significance of difference in favour of the liposomal formulation. Assessment for publication bias found that review results were robust.

AUTHORS' CONCLUSIONS

Current evidence suggests that liposomal amphotericin B is less nephrotoxic than conventional amphotericin B (when the effect on kidney function is measured as an increase in serum creatinine level equal to or greater than two-fold from the baseline level). We also found that there were fewer infusion-related reactions associated with the liposomal formulation.

Small intestinal fungal overgrowth

Small intestinal fungal overgrowth (SIFO) is characterized by the presence of excessive number of fungal organisms in the small intestine associated with gastrointestinal (GI) symptoms. Candidiasis is known to cause GI symptoms particularly in immunocompromised patients or those receiving steroids or antibiotics. However, only recently, there is emerging literature that an overgrowth of fungus in the small intestine of non-immunocompromised subjects may cause unexplained GI symptoms. Two recent studies showed that 26 % (24/94) and 25.3 % (38/150) of a series of patients with unexplained GI symptoms had SIFO. The most common symptoms observed in these patients were belching, bloating, indigestion, nausea, diarrhea, and gas. The underlying mechanism(s) that predisposes to SIFO is unclear but small intestinal dysmotility and use of proton pump inhibitors has been implicated. However, further studies are needed; both to confirm these observations and to examine the clinical relevance of fungal overgrowth, both in healthy subjects and in patients with otherwise unexplained GI symptoms. Importantly, whether eradication or its treatment leads to resolution of symptoms remains unclear; at present, a 2-3-week course of antifungal therapy is recommended and may be effective in improving symptoms, but evidence for eradication is lacking.

Flaws in design, analysis and interpretation of Pfizer's antifungal trials of voriconazole and uncritical subsequent quotations

We have previously described how a series of trials sponsored by Pfizer of its antifungal drug, fluconazole, in cancer patients with neutropenia handicapped the control drug, amphotericin B, by flaws in design and analysis. We describe similar problems in two pivotal trials of Pfizer's new antifungal agent, voriconazole, published in a prestigious journal. In a non-inferiority trial, voriconazole was significantly inferior to liposomal amphothericin B, but the authors concluded that voriconazole was a suitable alternative. The second trial used amphothericin B deoxycholate as comparator, but handicapped the drug by not requiring pre-medication to reduce infusion-related toxicity or substitution with electrolytes and fluid to reduce nephrotoxicity, although the planned duration of treatment was 84 days. Voriconazole was given for 77 days on average, but the comparator for only 10 days, which precludes a meaningful comparison. In a random sample of 50 references to these trials, we found that the unwarranted conclusions were mostly uncritically propagated. It was particularly surprising that relevant criticism raised by the FDA related to the first trial was only quoted once, and that none of the articles noted the obvious flaws in the design of the second trial. We suggest that editors ensure that the abstract reflects fairly on the remainder of the paper, and that journals do not impose any time limit for accepting letters that point out serious weaknesses in a study that have not been noted before.

Children in reviews: methodological issues in child-relevant evidence syntheses

BACKGROUND

The delivery of optimal medical care to children is dependent on the availability of child relevant research. Our objectives were to: i) systematically review and describe how children are handled in reviews of drug interventions published in the Cochrane Database of Systematic Reviews (CDSR); and ii) determine when effect sizes for the same drug interventions differ between children and adults.

METHODS

We systematically identified all of the reviews relevant to child health in the CDSR 2002, Issue 4. Reviews were included if they investigated the efficacy or effectiveness of a drug intervention for a condition that occurs in both children and adults. Information was extracted on review characteristics including study methods, results, and conclusions.

RESULTS

From 1496 systematic reviews, 408 (27%) were identified as relevant to both adult and child health; 52% (213) of these included data from children. No significant differences were found in effect sizes between adults and children for any of the drug interventions or conditions investigated. However, all of the comparisons lacked the power to detect a clinically significant difference and wide confidence intervals suggest important differences cannot be excluded. A large amount of data was unavailable due to inadequate reporting at the trial and systematic review level.

CONCLUSION

Overall, the findings of this study indicate there is a paucity of child-relevant and specific evidence generated from evidence syntheses of drug interventions. The results indicate a need for a higher standard of reporting for participant populations in studies of drug interventions.