micafungin and Disease-Models--Animal

The time the earth takes to rotate its axis (the day) has dictated how often pharmaceutical compounds are dosed. The scientific link between the 2 events is materia medica arcana. As an example, in the treatment of invasive candidiasis, antifungal therapy with intravenous micafungin is dosed daily. A literature review revealed population pharmacokinetic analyses, in vivo pharmacokinetics/pharmacodynamics studies, and maximum-tolerated-dose studies of micafungin that examined optimal micafungin dosing strategies. The half-life of micafungin in patient blood was 14 hours in several studies, but was even longer in different organs, so that the concentration will persist above minimum inhibitory concentrations of Candida species for several days. Studies in mice and rabbits with persistent neutropenia and disseminated candidiasis, otherwise fatal, demonstrated that a single large dose of micafungin could clear disseminated candidiasis, even though the micafungin half-life in such animals is shorter than in humans. Human pharmacokinetics/pharmacodynamics studies confirmed this link between micafungin efficacy and the ratio of the area under the concentration-time curve, and the optimal exposures initially identified in neutropenic animals. Maximum tolerated dose studies have demonstrated safety of 900 mg administered daily for several weeks, whereas case reports demonstrate efficacy and safety of single 1400-mg doses. Thus, a single dose of micafungin, or 2 such doses within a few days of each other, is not only logical, but might even lead to faster clearance of Candida.

Topics: Animals; Antifungal Agents; Candida; Candidiasis, Invasive; Clinical Trials as Topic; Disease Models, Animal; Dose-Response Relationship, Drug; Echinocandins; Half-Life; Humans; Lipopeptides; Maximum Tolerated Dose; Micafungin; Mice; Microbial Sensitivity Tests; Rabbits

Micafungin, a potent inhibitor of 1,3-beta-D-glucan synthase, has become the second available agent in the echinocandins class that is approved for use in clinical practice. This agent shares with caspofungin an identical spectrum of in vitro activity against Candida albicans, non-albicans species of Candida, and Aspergillus species, as well as several but not all pathogenic molds. If anything, its in vitro activity appears to be superior to that of caspofungin, although the clinical relevance of this observation is unclear. The clinical role of micafungin appears to be similar to that of caspofungin, although clinical data are still lacking at this stage, with initial approval only for treatment of esophageal candidiasis and prophylaxis in subjects with neutropenia. Pharmacokinetic and pharmacodynamic studies and reports of adverse effects and safety have reported similar but not identical results to those of other agents in the echinocandin class. Factors such as acquisition costs and the potential for resistance development may be more relevant to its widespread use than in vitro and in vivo data comparisons with caspofungin.

Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus; Candida; Candidiasis; Clinical Trials as Topic; Disease Models, Animal; Drug Resistance, Fungal; Echinocandins; Enzyme Inhibitors; Glucosyltransferases; Humans; Lipopeptides; Lipoproteins; Micafungin; Mice; Microbial Sensitivity Tests; Peptides, Cyclic

Invasive fungal infections are important causes of morbidity and mortality in hospitalised patients. Current therapy with amphotericin B and antifungal triazoles has overlapping targets and is limited by toxicity and resistance. Echinocandins are a new class of antifungal drugs, which inhibit the synthesis of 1,3-beta-D-glucan. This homopolysaccharide is an important component of the cell wall of many pathogenic fungi, providing osmotic stability and functioning in cell growth and cell division. Micafungin, which is a member of the echinocandin class, exhibits in vitro fungicidal or fungistatic activity against a variety of fungal pathogens which include Candida and Aspergillus species but not Cryptococcus, Fusarium or Zygomycetes. Micafungin demonstrates linear pharmacokinetics, which are not altered by drugs metabolised through the P450 enzyme system. The preclinical and clinical data strongly support the development of micafungin for treatment of proven or suspected mucosal and invasive Candida infections in immunocompetent and immunocompromised patients. This paper reviews the preclinical and clinical pharmacology of micafungin and its potential role for treatment of fungal invasive infections in patients.

Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus; Candida; Candidiasis; Disease Models, Animal; Echinocandins; Humans; Lipopeptides; Lipoproteins; Micafungin; Microbial Sensitivity Tests; Mycoses; Peptides, Cyclic; Randomized Controlled Trials as Topic

Combination therapy with amphotericin B and flucytosine is considered to be the treatment of choice for cryptococcal infections. However, for other infections and combinations of antifungal infections, the data are less clear-cut. The concurrent use of amphotericin B with an azole has elicited controversy, given the potential of antimicrobial antagonism. The results of one recent candidemia study suggest that the potential antagonism may not be an issue; the combination of amphotericin B and fluconazole provided more effective clearance of Candida from the bloodstream than did fluconazole used alone. Several in vitro and animal studies have shown antagonism between the azoles and amphotericin B for aspergillosis. However, introduction of the new class of agents that target beta-glucan synthase (echinocandins) has invigorated the prospects of combination therapy. The echinocandins and polyenes are not antagonistic, and there is evidence that the echinocandins may provide additive to synergistic activity in combination with triazoles. For patients whose aspergillosis is progressing despite monotherapy, the addition of a second agent, such as an echinocandin, may be reasonable.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Azoles; Candidiasis; Caspofungin; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Echinocandins; Fluconazole; Humans; In Vitro Techniques; Lipopeptides; Lipoproteins; Micafungin; Mycoses; Peptides, Cyclic; Pyrimidines; Randomized Controlled Trials as Topic; Time Factors; Treatment Outcome; Triazoles; Voriconazole

To describe micafungin pharmacokinetic (PK) alterations of sepsis induced in piglets and to determine whether the porcine septic model is able to predict the PK of micafungin in septic patients at the plasma and peritoneal sites.. From healthy (n = 8) and septic piglet group (n = 16), total micafungin concentrations were subject to a population PK analysis using Monolix®. Data from 16 septic humans patients from others studies was used to compare micafungin PK between septic piglets and septic patients.. Sepsis induced in piglets slightly alters the total clearance and the volume of distribution, while inter-compartment clearance is increased (from 3.88 to 5.74 L/h) as well as the penetration into peritoneal cavity (from 61 to 90%). In septic human patients, PK parameters are similar except for the Vd, which is corrected by an allometric factor based on the body weight of each species. Micafungin penetration into peritoneal cavity of humans is lower than in septic piglets (40 versus 90%).. The sepsis induced in the porcine model alters the PK of micafungin comparable to that in humans. In addition, micafungin PK is similar between these two species at the plasma level taking into account the allometric relationship of the body weight of these species on the central volume of distribution. The porcine septic plasma model would be able to predict the micafungin PK in the septic patients. However, further studies on peritoneal penetration are necessary to characterize this inter-species difference.

Topics: Animals; Antifungal Agents; Biological Variation, Population; Disease Models, Animal; Female; Humans; Micafungin; Peritoneum; Sepsis; Species Specificity; Swine

In cases where catheter-related candidemia (CRC) must be managed without catheter withdrawal, antifungal lock therapy using highly active anti-biofilm (HAAB) agents is combined with systemic treatment. However, the activity of HAAB agents has never been studied in in vivo models using bioluminescence. We assessed the efficacy of micafungin using a bioluminescent Candida albicans SKCA23-ACTgLuc strain in an animal model of CRC. We divided 33 female Wistar rats into five groups: sham (A), infected nontreated (B), treated with lock therapy (0.16 mg/ml) (C), systemically treated only (1 mg/kg) (D), and systemically treated+lock (E). Catheters were colonized 24 h before insertion into the femoral vein (day 0). Treatment started on day 1 and lasted 7 days, followed by 7 days of surveillance. Bioluminescence assays were carried out on days 1, 3, 5, and 14, together with daily monitoring of clinical variables. Postmortem microbiological cultures from the catheter and several tissue samples were also obtained. Overall, 28 rats (84.8%) completed the study. Group B animals showed significant weight loss at days 2, 4, and 5 compared with groups C and D (P < .05). In group B, no animals survived after day 7, 75% had CRC, and bioluminescence remained constant 5 days after catheter implantation. Positive catheter culture rates in groups C, D, and E were, respectively, 83.3%, 62.5%, and 25.0% (P = .15). Micafungin proved to be a HAAB agent when administered both systemically and in lock therapy in an animal model of CRC, although the bioluminescence signal persists after treatment. This persistence should be further analyzed.

Topics: Animal Structures; Animals; Antifungal Agents; Biofilms; Candida albicans; Candidemia; Catheter-Related Infections; Catheters; Disease Models, Animal; Female; Luminescent Measurements; Micafungin; Rats, Wistar; Survival Analysis; Treatment Outcome

Candida peritonitis is a crucial disease, however the optimal antifungal therapy regimen has not been clearly defined. Peritoneal fibrosis (PF) can be caused by abdominal surgery, intra-abdominal infection, and malignant diseases, and is also widely recognized as a crucial complication of long-term peritoneal dialysis. However, the influence of PF on Candida peritonitis prognosis remains unknown. Here, we evaluated the severity of Candida peritonitis within the context of PF and the efficacy of micafungin using mice. A PF mouse model was generated by intraperitoneally administering chlorhexidine gluconate. Candida peritonitis, induced by intraperitoneal inoculation of Candida albicans, was treated with a 7-day consecutive subcutaneous administration of micafungin. Candida infection caused a higher mortality rate in the PF mice compared with the control mice on day 7. Proliferative Candida invasion into the peritoneum and intra-abdominal organs was confirmed pathologically only in the PF mice. However, all mice in both groups treated with micafungin survived until day 20. Micafungin treatment tends to suppress inflammatory cytokines in the plasma 12 h after infection in both groups. Our results suggest that PF enhances early mortality in Candida peritonitis. Prompt initiation and sufficient doses of micafungin had good efficacy for Candida peritonitis, irrespective of the underlying PF.

Topics: Animals; Antifungal Agents; Biomarkers; Candida; Cytokines; Disease Models, Animal; Histocytochemistry; Humans; Micafungin; Mice; Peritoneal Fibrosis; Peritonitis; Prognosis; Treatment Outcome

We studied the ability of five echinocandin-susceptible C. glabrata isolates to acquire in vitro resistance to anidulafungin and micafungin. All isolates became phenotypically resistant after 2-4 days of exposure to low and constant micafungin concentrations (P < .05). Mutations in the HS1 region of the FKS2 gene were found in all isolates. The acquisition of resistance was not related to the previous use of antifungal treatment in the patients or the presence of mutations at MSH2 gene. We found differences (P < .0001) in the median survival of Galleria mellonella larvae infected with FKS2 mutant isolates (5 days) and wild-type isolates (3 days).

Topics: Anidulafungin; Animals; Antifungal Agents; Candida glabrata; Candidiasis; Disease Models, Animal; DNA Mutational Analysis; Drug Resistance, Fungal; Glucosyltransferases; Lepidoptera; Micafungin; Mutation; Survival Analysis

We determined micafungin, caspofungin and amphotericin B (AMB) minimum inhibitory concentration (MICs) and killing rates in RPMI-1640 and in RPMI-1640 with 50% serum against three Candida krusei bloodstream isolates. MIC ranges in RPMI-1640 were 0.125-0.25, 0.25 and 0.125-0.5 mg/L, in RPMI-1640 with 50% serum, MICs were 64-128-, 8- and 4-16-fold higher, respectively. In RPMI-1640 micafungin and caspofungin at 1, 4, 16 and 32 mg/L as well as AMB at 2 mg/L were fungicidal against all isolates in ≤3.96, ≤4.42 and 14.96 h, respectively. In RPMI-1640 with 50% serum, caspofungin was fungicidal for all isolates only at 32 mg/L, micafungin and AMB were fungistatic. In neutropenic mice, 5 mg/kg caspofungin and 1 mg/kg AMB were ineffective against two of the three isolates. Thus, in vivo efficacy of echinocandins and AMB is weak or absent against C. krusei. Prescribers treating C. krusei infections with echinocandins should watch out for clinical resistance and therapeutic failure.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Candidemia; Caspofungin; Disease Models, Animal; Drug Evaluation, Preclinical; Humans; Micafungin; Microbial Sensitivity Tests

The formation of Candida biofilms on implanted medical devices is crucial to the development of infections and an important clinical problem because of elevated resistance to antifungals. The aim of this study was to compare the in vitro activity of liposomal amphotericin B (L-AMB) and micafungin (MCFG) against four species of Candida biofilms, and the efficacy of systemic plus lock therapy with L-AMB and MCFG in a Candida biofilm-associated catheter infection model. An XTT-reduction assay was used to measure the metabolic activity of the biofilms to evaluation of in vitro antibiofilm activity. MCFG had better in vitro activity than L-AMB against Candida glabrata biofilms, whereas L-AMB had better activity than MCFG against Candida albicans and Candida tropicalis biofilms. L-AMB and MCFG had comparable efficacy against Candida parapsilosis biofilms. In an in vitro lock therapy model, 2 mg/ml L-AMB, unlike 2 mg/ml MCFG, significantly reduced the metabolic activity of all the strains of biofilms by >96%. Systemic and intraluminal lock treatment with L-AMB for 3-days resulted in more than about 2 log

Topics: Amphotericin B; Animals; Antifungal Agents; Biofilms; Candida albicans; Candida glabrata; Candida parapsilosis; Candida tropicalis; Catheter-Related Infections; Disease Models, Animal; Humans; Male; Micafungin; Mice; Mice, Inbred Strains; Treatment Outcome

Intra-abdominal candidiasis (IAC) is a prominent invasive fungal infection associated with high mortality. Prompt antifungal therapy and source control are crucial for successful treatment. Echinocandin antifungal drugs are first-line agents; however, their clinical effectiveness is highly variable, with known potential for breakthrough resistance, and little is known about drug exposure at the site of infection. Using matrix-assisted desorption ionization mass spectrometry imaging technology, we investigated the spatial and quantitative distribution in tissue lesions for two echinocandin drugs, micafungin and CD101, in a clinically relevant IAC mouse model. Drug accumulation within lesions was observed with both drugs at their humanized therapeutic doses. CD101, but not micafungin, accumulated in lesions at levels above the mutant prevention concentration of the infecting strain. These findings indicate that current echinocandin drugs are limited by penetration at the site of infection and have implications for clinical outcomes and emergence of resistance in patients with IAC.

Topics: Abdominal Abscess; Animals; Antifungal Agents; Candida albicans; Candidiasis; Disease Models, Animal; Drug Resistance, Fungal; Echinocandins; Female; Lipopeptides; Micafungin; Mice; Microbial Sensitivity Tests; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

The echinocandin family of drugs is well characterized for antifungal function that inhibits β-D-glucan synthesis. The aim of this work was to study whether micafungin, a member of the echinocandin family, elicits additional activities that prime the host's immune response. We found that in a Galleria mellonella model, prophylactic treatment with micafungin extended the life of Staphylococcus aureus-infected larvae (a pathogen to which the drug demonstrates no direct antimicrobial activity) compared to insects that did not receive micafungin (P < 0.05). The inhibition of pathogens in the G. mellonella infection model was characterized by a 2.43-fold increase in hemocyte density, compared to larvae inoculated with PBS. In a murine model where animals were provided micafungin prophylaxis 3 days prior to macrophage collection, macrophages were found associated with an average 0.9 more fungal cells per macrophage as compared to saline-treated animals. Interestingly, micafungin-stimulated macrophages killed 11.6 ± 6.2 % of fungal cells compared to 3.8 ± 2.4 % of macrophages from saline-treated animals. The prophylactic provision of micafungin prior to Candida albicans infection was characterized by an increase in the proinflammatory cytokines CXCL13 and SPP1 by 11- and 6.9-fold, respectively. In conclusion, micafungin demonstrated the ability to stimulate phagocytic cells and promote an immune response that can inhibit microbial infections.

Topics: Animals; Candida albicans; Disease Models, Animal; Echinocandins; Immunologic Factors; Lepidoptera; Lipopeptides; Macrophages; Micafungin; Mice; Microbial Viability; Staphylococcal Infections; Survival Analysis; Treatment Outcome

The pharmacokinetic/pharmacodynamic (PK/PD) characteristics of the echinocandins favor infrequent administration of large doses. The in vivo investigation reported here tested the utility of a range of humanized dose levels of micafungin using a variety of prolonged dosing intervals for the prevention and therapy of established disseminated candidiasis. Humanized doses of 600 mg administered every 6 days prevented fungal growth in prophylaxis. Humanized doses of 300 to 1,000 mg administered every 6 days demonstrated efficacy for established infections.

Topics: Animals; Antifungal Agents; Candida; Candidiasis; Disease Models, Animal; Drug Administration Schedule; Echinocandins; Humans; Lipopeptides; Micafungin; Mice; Microbial Sensitivity Tests; Treatment Outcome

The aim of the present study was to evaluate the effects of delayed antifungal therapy on the outcome of invasive aspergillosis due to Aspergillus fumigatus in experimental models of infection.. A clinical isolate of A. fumigatus susceptible to amphotericin B (MIC 0.5 mg/L) and micafungin [minimum effective concentration (MEC) 0.03 mg/L] was used in all experiments. Two models of infection were investigated in immunosuppressed mice: disseminated infection and pulmonary infection. Twenty-four hours (early therapy) and 48 h (delayed therapy) post-infection, the mice were given vehicle, liposomal amphotericin B, micafungin or liposomal amphotericin B plus micafungin (combination). Drug efficacy was assessed by either survival or tissue burden experiments.. In disseminated infection, any drug regimen given early significantly prolonged survival. When therapy was delayed, only micafungin and the combination were effective. In pulmonary infection, although there was a trend towards a prolongation of survival of mice treated early with liposomal amphotericin B, only the combination was effective. Similarly, when therapy was delayed, only the combination was effective. In disseminated infection, any drug regimen given early was effective at reducing the cfu in kidney tissue. In pulmonary infection, only liposomal amphotericin B and the combination given early were effective at reducing the cfu in lung tissue. Conversely, when therapy was delayed, no regimen was effective at reducing the tissue burden, regardless of the type of infection.. Our data indicate that delayed initiation of antifungal therapy is deleterious in experimental models of invasive aspergillosis. A combination regimen seems to have some advantages over a single-drug approach when the therapy is started late.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Colony Count, Microbial; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Female; Invasive Pulmonary Aspergillosis; Lipopeptides; Lung; Micafungin; Mice; Microbial Sensitivity Tests; Survival Analysis; Time Factors; Treatment Outcome

This study evaluated the in vitro and in vivo activity of micafungin alone and in combination with the iron chelator deferasirox against Pythium insidiosum. Micafungin showed a poor in vitro activity when it was used alone, but synergistic interactions were observed for 88.2% of the strains when the drug was combined with deferasirox. Smaller lesions were observed in infected rabbits receiving the combination therapy, although it favored disease dissemination to the lungs. The present results show that micafungin alone is ineffective against P. insidiosum, and the combination micafungin-deferasirox might have deleterious effects for the host.

Topics: Animals; Antifungal Agents; Benzoates; Deferasirox; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Female; Horse Diseases; Horses; Lipopeptides; Micafungin; Microbial Sensitivity Tests; Pythiosis; Pythium; Rabbits; Triazoles

Candida biofilm-associated infections of central venous catheters are a challenging therapeutic problem. Recent in vitro and in vivo studies of the structure, formation, pathogenesis, and treatment establish a rationale for new approaches to management of these tenacious infections.

Topics: Anidulafungin; Animals; Antifungal Agents; Biofilms; Candida; Candidiasis; Caspofungin; Catheter-Related Infections; Disease Models, Animal; Drug Resistance, Fungal; Echinocandins; Humans; Lipopeptides; Micafungin; Microbial Sensitivity Tests; Vascular Access Devices

The current standard of treatment of invasive candidiasis with echinocandins requires once-daily therapy. To improve quality of life, reduce costs, and improve outcome, we studied the pharmacokinetics (PK), efficacy, and safety of alternate dosing regimens of micafungin (MFG) for the treatment of experimental subacute disseminated candidiasis.. MFG was administered for 12 days starting 24 hours after intravenous inoculation of 1 × 10(3) Candida albicans blastoconidia. Study groups consisted of MFG at 1 mg/kg every 24 hours (MFG1), 2 mg/kg every 48 hours (MFG2), and 3 mg/kg every 72 hours (MFG3), and untreated controls. PK of MFG were determined on day 7 by high-performance liquid chromatography and modeled using nonparametric adaptive grid program. A 2-compartment PK model with volume of the central compartment (Vc), clearance (SCL), and the intercompartmental rate constants Kcp and Kpc was used. The fungal burden in 7 tissues was determined 312 hours after the initiation of therapy.. PK of MFG were linear and the parameter means ± SD were Vc = 0.41 ± 0.18 L, Kcp = 2.80 ± 1.55/hour, Kpc = 1.71 ± 0.93/hour, and SCL = 0.16 ± 0.003 L/hour (r(2) = 0.99). The area under the plasma drug concentration - time curve for MFG1, MFG2, and MFG3 was 198.7 ± 19.8, 166.3 ± 36.7, and 192.8 ± 46.2 mg × hour/L, respectively (P = .24). All treatment groups showed significant and comparable resolution of (1→3)-β-D-glucan levels and clearance of C. albicans from liver, spleen, kidney, brain, lung, vitreous humor, and vena cava in comparison to untreated controls (P ≤ .05). There were no differences in hepatic or renal function among study groups.. Less fractionated MFG regimens of every 48 and 72 hours are safe and as effective in experimental disseminated candidiasis as once-daily therapy in neutropenic hosts.

Topics: Animals; Antifungal Agents; beta-Glucans; Candida albicans; Candidiasis; Candidiasis, Invasive; Colony Count, Microbial; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Echinocandins; Female; Lipopeptides; Micafungin; Neutropenia; Proteoglycans; Rabbits

KB425796-C is a novel antifungal metabolite produced by the newly isolated bacterial strain Paenibacillus sp. No. 530603. This compound is a 40-membered macrocyclic lipopeptidolactone consisting of 12 amino acids and a 3-hydroxy-15-methylpalmitoyl moiety. KB425796-C displayed antifungal activity against micafungin-resistant fungi and was fungicidal to Trichosporon asahii in vitro. In a murine systemic infection model of T. asahii, KB425796-C showed excellent efficacy upon i.p. administration at 32 mg kg(-1). In addition, KB425796-C induced morphological changes in the hyphae of Aspergillus fumigatus and had fungicidal effects in combination with micafungin. In a mouse model of septic A. fumigatus infection, although non-treated mice survived for a maximum of only 6 days, the survival rate of micafungin-treated mice (0.1 mg kg(-1)) increased to 20%, while the survival rate of mice treated with a combination of micafungin (0.1 mg kg(-1)) and KB425796-C (32 mg kg(-1)) increased to 100% during the 31-day post-infection period. Our findings suggest that KB425796-C is a good candidate for the treatment of aspergillosis in combination with micafungin.

Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Depsipeptides; Disease Models, Animal; Drug Resistance, Fungal; Drug Synergism; Drug Therapy, Combination; Echinocandins; Female; Injections, Intraperitoneal; Lipopeptides; Micafungin; Mice; Mice, Inbred DBA; Mice, Inbred ICR; Paenibacillus; Sepsis; Survival Rate; Trichosporon; Trichosporonosis

The aim of this study was to compare the in vitro and in vivo activities of micafungin, caspofungin, and anidulafungin against Candida glabrata. The MICs against 28 clinical isolates showed that the overall susceptibilities to caspofungin and to micafungin were not statistically different in the absence of human serum, whereas the isolates were less susceptible to micafungin than to caspofungin in its presence. Minimum fungicidal concentrations, as well as time-kill experiments, showed that caspofungin was more active than anidulafungin, while micafungin was superior to either caspofungin or anidulafungin without serum; its addition rendered caspofungin and micafungin equally effective. A murine model of systemic candidiasis against a C. glabrata-susceptible isolate was performed to study the effects of all three echinocandins, and kidney burden counts showed that caspofungin, micafungin, and anidulafungin were active starting from 0.25, 1, and 5 mg/kg of body weight/day, respectively. Two echinocandin-resistant strains of C. glabrata were selected: C. glabrata 30, a laboratory strain harboring the mutation Fks2p-P667T, and C. glabrata 51, a clinical isolate harboring the mutation Fks2p-D666G. Micafungin activity was shown to be as effective as or more effective than that of caspofungin or anidulafungin in terms of MICs. In vivo studies against these resistant strains showed that micafungin was active starting from 1 mg/kg/day, while caspofungin was effective only when administrated at higher doses of 5 or 10 mg/kg/day. Although a trend toward colony reduction was observed with the highest doses of anidulafungin, a significant statistical difference was never reached.

Topics: Anidulafungin; Animals; Antifungal Agents; Candida glabrata; Candidiasis; Caspofungin; Disease Models, Animal; Drug Resistance, Fungal; Echinocandins; Female; Humans; Lipopeptides; Micafungin; Mice; Microbial Sensitivity Tests; Mutation

We recently observed that the micafungin MICs for some Candida glabrata fks hot spot mutant isolates are less elevated than those for the other echinocandins, suggesting that the efficacy of micafungin may be differentially dependent on such mutations. Three clinical C. glabrata isolates with or without (S3) fks hot spot mutations R83 (Fks2p-S663F) and RR24 (Fks1p-S629P) and low, medium, and high echinocandin MICs, respectively, were evaluated to assess the in vivo efficacy in an immunocompetent mouse model using three doses of each echinocandin. Drug concentrations were determined in plasma and kidneys by high-performance liquid chromatography (HPLC). A pharmacokinetic-pharmacodynamic mathematical model was used to define the area under the concentration-time curve (AUC) that produced half- and near-maximal activity. Micafungin was equally efficacious against the S3 and R83 isolates. The estimates for the AUCs of each echinocandin that induced half-maximal effect (E(50)s) were 194.2 and 53.99 mg · h/liter, respectively. In contrast, the maximum effect (E(max)) for caspofungin was higher against S3 than R83, but the estimates for E(50) were similar (187.1 and 203.5 mg · h/liter, respectively). Anidulafungin failed to induce a ≥1-log reduction for any of the isolates (AUC range, 139 to 557 mg · h/liter). None of the echinocandins were efficacious in mice challenged with the RR24 isolate despite lower virulence (reduced maximal growth, prolonged lag phase, and lower kidney burden). The AUC associated with half-maximal effect was higher than the average human exposure for all drug-dose-bug combinations except micafungin and the R83 isolate. In conclusion, differences in micafungin MICs are associated with differential antifungal activities in the animal model. This study may have implications for clinical practice and echinocandin breakpoint determination, and further studies are warranted.

Topics: Anidulafungin; Animals; Antifungal Agents; Area Under Curve; Biological Availability; Candida glabrata; Candidiasis; Caspofungin; Chromatography, High Pressure Liquid; Disease Models, Animal; Drug Resistance, Fungal; Echinocandins; Genes, Fungal; Glucosyltransferases; Humans; Kidney; Lipopeptides; Micafungin; Mice; Microbial Sensitivity Tests; Mutation

To investigate the correlation between in vitro killing activity and in vivo efficacy of micafungin (MCFG) and liposomal amphotericin B (L-AMB) against Candida tropicalis in a neutropenic murine lethal infection model.. Candida albicans (one strain) and C. tropicalis (three strains) were tested in time-kill studies. Cyclophosphamide-treated mice were inoculated intravenously with each strain. One day after inoculation, antifungals were administered intravenously once daily for 1 or 3 days.. MCFG exhibited fungicidal activity against C. albicans ATCC 90029 and C. tropicalis SP-20142, and fungistatic activity against C. tropicalis ATCC 42678 and SP-20047. The ED(50)s (dosage that results in 50% survival) of MCFG for C. tropicalis ATCC 42678 and SP-20047 (4.1-50 mg/kg) were higher than those for other strains (1.6-12 mg/kg). A 1-day course of MCFG was not effective against C. tropicalis ATCC 42678 and SP-20047 at the clinical dose (5 mg/kg), which achieved an AUC level almost equal to that of 100 mg in humans, whereas a 3-day course of 5 mg/kg MCFG was efficacious against all strains. In contrast, L-AMB showed fungicidal activity against all strains tested and the ED(50)s of L-AMB were 0.08-0.65 mg/kg. In both treatment regimens, the minimum effective doses of L-AMB (≤0.5 mg/kg) were less than the clinical dosage (≤5 mg/kg).. The in vivo efficacy of MCFG and L-AMB showed a correlation with the in vitro killing activity. At the clinical dose, L-AMB exerted anti-C. tropicalis activity within a shorter treatment period than MCFG.

Topics: Amphotericin B; Animals; Antifungal Agents; Area Under Curve; Candida tropicalis; Candidiasis; Disease Models, Animal; Echinocandins; Lipopeptides; Male; Micafungin; Mice; Microbial Sensitivity Tests; Neutropenia

Liposomal amphotericin B (LAmB) combined wither either micafungin or deferasirox was synergistic in previous murine studies with mucormycosis or aspergillosis. We hypothesized that triple therapy using LAmB, micafungin, and deferasirox could further improve outcomes of mucormycosis or aspergillosis. Triple therapy improved survival and reduced tissue fungal burden of mice with mucormycosis and to a lesser extent with aspergillosis. Continued investigation into the use of triple therapy against mucormycosis and aspergillosis is warranted.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Echinocandins; Iron Chelating Agents; Lipopeptides; Micafungin; Mice; Mice, Inbred BALB C; Mucormycosis; Polyenes; Rhizopus

Invasive pulmonary aspergillosis remains problematic in immunocompromised patient populations. We studied potential therapeutic options in a murine model of pulmonary aspergillosis in triamcinolone-suppressed DBA/2 mice infected intranasally with conidia from Aspergillus fumigatus. Mice were treated with liposomal-amphotericin B (AmBi; AmBisome), lipid-complexed amphotericin B (ABLC; Abelcet), voriconazole (VCZ), micafungin (MICA), caspofungin (CAS) or deoxycholate amphotericin B (AMBd) given alone or in combination. Monotherapy with AmBi, ABLC, AMBd, CAS or MICA had activity in prolonging survival; however, only AMBd or CAS reduced fungal burden in the lungs and kidneys. Combinations of AmBi plus CAS or MICA prolonged survival, but were not better than monotherapy. VCZ was ineffective and AMBd plus CAS showed a possible antagonism. AmBi or ABLC at higher dosages, or loading-doses of AmBi resulted in reduced survival. Histopathology showed increased incidence of serious renal and mild hepatic toxicity in triamcinolone-treated mice given an amphotericin B regimen compared to no or only triamcinolone (minimal renal changes occurred with CAS or VCZ with or without triamcinolone); suggestive of combined toxicity of triamcinolone and the amphotericin B in AmBi or ABLC. Infected treated mice showed progressive pulmonary disease including abscesses, angioinvasion and abundant intralesional fungi. High loading-doses of AmBi were associated with nephrosis and damage to other tissues. No monotherapy or combination regimen showed superiority for the treatment of pulmonary aspergillosis in corticosteroid suppressed mice and the potential for combined drug toxicity was enhanced in these mice. High dosages of lipid-formulated amphotericin B also proved unsatisfactory. Additional studies are needed to evaluate improved treatment.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Caspofungin; Colony Count, Microbial; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Echinocandins; Humans; Invasive Pulmonary Aspergillosis; Lipopeptides; Male; Micafungin; Mice; Mice, Inbred DBA; Pyrimidines; Triazoles; Voriconazole

We examined whether the pharmacokinetic disposition of micafungin (MCFG), an echinocandin class antifungal agent, is altered in hyperbilirubinemia using a rat model prepared by bile duct ligation (BDL). Serum bilirubin levels were increased depending upon the duration of BDL. The elimination rate constant and total body clearance (CL(tot)) of MCFG were reduced by 24% and 16%, respectively, after BDL for 1 h, but there was no significant change in the apparent volume of distribution at steady-state. The degree of reduction in the CL(tot) was much greater 7 days after BDL as compared with that 1 h after BDL (44% vs. 16%). However, the proportion of the biliary clearance in the CL(tot) was about 10%. This is similar to the extent of decrease in the CL(tot) by occlusion of the bile duct, demonstrating that decreased biliary excretion of MCFG makes only a minor contribution to its pharmacokinetic change. These findings suggest that the metabolic capacity of MCFG is markedly impaired in hepatic hypofunction secondary to hyperbilirubinemia, providing a fundamental explanation for the previous clinical report that there is a significant correlation between dose-adjusted plasma MCFG concentration and serum bilirubin levels.

Topics: Animals; Antifungal Agents; Bile; Bilirubin; Cholestasis; Disease Models, Animal; Echinocandins; Hyperbilirubinemia; Injections, Intravenous; Lipopeptides; Male; Metabolic Clearance Rate; Micafungin; Rats; Rats, Sprague-Dawley

Aminocandin (IP960; HMR3270; NXL201) is a new echinocandin with broad-spectrum in vitro activity against Aspergillus and Candida spp. We compared the activity of aminocandin with that of amphotericin B (AmB), itraconazole (ITC) and caspofungin (CAS) in murine models of disseminated aspergillosis against three strains of A. fumigatus, two of which were fully susceptible (AF293 and A1163) and one was resistant to ITC (AF91). Mice were rendered temporarily neutropenic or persistently neutropenic with cyclophosphamide and were infected intravenously 3 days later. Temporarily neutropenic mice were treated with either intraperitoneal (i.p.) AmB (5mg/kg/dose), oral (p.o.) ITC (25mg/kg/dose), intravenous (i.v.) aminocandin (0.25-10mg/kg/dose), i.p. aminocandin (1mg/kg/dose) or solvent control for 9 days. Mice were euthanised 11 days post infection and the kidneys and liver were removed for quantitative culture. Following infection with AF293, only aminocandin 5mg/kg i.v. yielded 100% survival. Aminocandin 1mg/kg i.v., AmB 5mg/kg i.p. or ITC 25mg/kg p.o. were equivalent (P>0.05). Aminocandin 5mg/kg was superior to aminocandin 0.25mg/kg (P<0.0001) as well as all controls (P<0.0001) in reducing mortality. Following infection with AF91, only aminocandin at 5mg/kg and 1mg/kg i.v. yielded 100% survival, which was superior to ITC, aminocandin 0.25mg/kg and controls (all P<0.0001). In the persistently neutropenic model with A1163, aminocandin, CAS and micafungin (2-10mg/kg) were all effective at prolonging survival, with some impact on reducing culture burdens, even with alternate-day dosing (4mg/kg). The only fungicidal regimen was aminocandin 5mg/kg, which sterilised 40% and 50% of mice following infection with AF293 and AF91, respectively. Aminocandin at doses of > or =1mg/kg is highly effective in reducing mortality and organ burden in disseminated infection caused by ITC-susceptible and -resistant A. fumigatus.

Topics: Administration, Oral; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Caspofungin; Colony Count, Microbial; Disease Models, Animal; Echinocandins; Injections, Intraperitoneal; Injections, Intravenous; Itraconazole; Kidney; Lipopeptides; Liver; Male; Micafungin; Mice; Survival Analysis; Treatment Outcome

We report the appearance of Candida glabrata strains with reduced sensitivity during treatment with the echinocandin drug micafungin (MCF). Four C. glabrata strains were isolated from sputum, gastric juice, and blood taken from a patient during hospitalization. Two of these strains, one of which was obtained after treatment with MCF for suspected Candida pneumonia and the other of which was obtained during MCF treatment for candidemia, were isolated from blood and found to have a reduced susceptibility to MCF. These two clinical isolates showed a high minimum inhibitory concentration (MIC) for MCF, with this change in MIC being unique for MCF among established antifungal drugs. To further investigate the mechanism underlying this reduced sensitivity, an in vivo mouse infection model and in vitro enzymatic analysis were performed. MCF had little effect in the mouse disseminated infection model and enzymatic analysis showed the low affinity of MCF to the 1,3-Beta-D-glucan synthase of the clinical isolates, although the enzymes of both clinical isolates and control strain were noncompetitively inhibited by MCF. Taken together, this low affinity of MCF for the enzymes is likely to cause the reduced sensitivities. These data further indicate that MCF could induce acquired MCF-resistant strains during clinical use.

Topics: Aged; Animals; Antifungal Agents; Body Temperature; Candida glabrata; Candidemia; Disease Models, Animal; Echinocandins; Fatal Outcome; Female; Glucosyltransferases; Humans; Kinetics; Lipopeptides; Male; Micafungin; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests

We tested ten day courses of amphotericin B (AMB), micafungin (MFG), voriconazole (VRC), flucytosine (5FC) and posaconazole (PSC) alone and in double or triple combinations in the treatment of disseminated infections caused by Cladophialophora bantiana in a murine model. Animals were monitored for survival for 40 days. We found that PSC at 100 mg/kg or 5FC at 180 mg/kg prolonged survival over controls. The combinations PSC+MFG and PSC+5FC improved survival compared to MFG and 5FC alone, but were not superior to PSC alone. The triple combination of PSC+MFG+5FC improved the survival with respect to both the control group and the component monotherapies, but all the animals died during the experiment. When treatment with this triple therapy was extended up to 30 days, half of the animals survived for at least 10 months. Combination therapy with the three drugs (PSC, MFG and 5FC) appears to be a promising option for the treatment of C. bantiana infections.

Topics: Amphotericin B; Animals; Antifungal Agents; Ascomycota; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Flucytosine; Humans; Lipopeptides; Male; Micafungin; Mice; Mycoses; Treatment Outcome; Triazoles

We have evaluated the efficacies of micafungin, amphotericin B, and voriconazole, alone and in double and triple combinations, in a murine model of systemic infection by Scedosporium prolificans. Micafungin combined with voriconazole or amphotericin B was the most effective, these being the only treatments able to prolong survival and to reduce the fungal load in the kidneys and brain. Triple combinations of these drugs did not improve the results obtained with double combinations.

Topics: Amphotericin B; Animals; Antifungal Agents; Brain; Disease Models, Animal; Drug Resistance, Fungal; Drug Therapy, Combination; Echinocandins; Humans; Kidney; Lipopeptides; Male; Micafungin; Mice; Microbial Sensitivity Tests; Mycetoma; Pyrimidines; Scedosporium; Treatment Outcome; Triazoles; Voriconazole

Candida albicans is the leading fungal pathogen of humans, causing life-threatening disease in immunocompromised individuals. Treatment of candidiasis is hampered by the limited number of antifungal drugs whose efficacy is compromised by host toxicity, fungistatic activity, and the emergence of drug resistance. We previously established that the molecular chaperone Hsp90, which regulates the form and function of diverse client proteins, potentiates resistance to the azoles in C. albicans and in the model yeast Saccharomyces cerevisiae. Genetic studies in S. cerevisiae revealed that Hsp90's role in azole resistance is to enable crucial cellular responses to the membrane stress exerted by azoles via the client protein calcineurin. Here, we demonstrate that Hsp90 governs cellular circuitry required for resistance to the only new class of antifungals to reach the clinic in decades, the echinocandins, which inhibit biosynthesis of a critical component of the fungal cell wall. Pharmacological or genetic impairment of Hsp90 function reduced tolerance of C. albicans laboratory strains and resistance of clinical isolates to the echinocandins and created a fungicidal combination. Compromising calcineurin function phenocopied compromising Hsp90 function. We established that calcineurin is an Hsp90 client protein in C. albicans: reciprocal co-immunoprecipitation validated physical interaction; Hsp90 inhibition blocked calcineurin activation; and calcineurin levels were depleted upon genetic reduction of Hsp90. The downstream effector of calcineurin, Crz1, played a partial role in mediating calcineurin-dependent stress responses activated by echinocandins. Hsp90's role in echinocandin resistance has therapeutic potential given that genetic compromise of C. albicans HSP90 expression enhanced the efficacy of an echinocandin in a murine model of disseminated candidiasis. Our results identify the first Hsp90 client protein in C. albicans, establish an entirely new role for Hsp90 in mediating resistance to echinocandins, and demonstrate that targeting Hsp90 provides a promising therapeutic strategy for the treatment of life-threatening fungal disease.

Topics: Analysis of Variance; Animals; Antifungal Agents; Azoles; Calcineurin; Candida albicans; Candidiasis; Disease Models, Animal; DNA-Binding Proteins; Drug Resistance, Fungal; Echinocandins; Fungal Proteins; HSP90 Heat-Shock Proteins; Lipopeptides; Male; Micafungin; Mice; Stress, Physiological; Transcription Factors

SPK-843, a new polyene antifungal, exhibited dose-dependent efficacy on murine pulmonary aspergillosis models. SPK-843 doses of higher than 1.0 mg/kg of body weight exhibited no renal toxicities and a tendency toward better survival prolongation than the estimated maximum tolerated doses of amphotericin B (Fungizone) (1.0 mg/kg) and liposomal amphotericin B (AmBisome) (8.0 mg/kg).

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus flavus; Disease Models, Animal; Dose-Response Relationship, Drug; Echinocandins; Lipopeptides; Lipoproteins; Lung Diseases, Fungal; Male; Micafungin; Mice; Polyenes; Treatment Outcome

Previous studies using in vivo candidiasis models have demonstrated that the concentration-associated pharmacodynamic indices, the maximum concentration of a drug in serum/MIC and 24-h area under the curve (AUC)/MIC, are associated with echinocandin treatment efficacy. The current investigations used a neutropenic murine model of disseminated Candida albicans and C. glabrata infection to identify the 24-h AUC/MIC index target associated with a stasis and killing endpoint for the echinocandin, micafungin. The kinetics after intraperitoneal micafungin dosing were determined in neutropenic infected mice. Peak levels and AUC values were linear over the 16-fold dose range studied. The serum drug elimination half-life ranged from 7.5 to 16 h. Treatment studies were conducted with 4 C. albicans and 10 C. glabrata isolates with micafungin MICs varying from 0.008 to 0.25 microg/ml to determine whether similar 24-h AUC/MIC ratios were associated with efficacy. The free drug AUC/MICs associated with stasis and killing (1-log) endpoints were near 10 and 20, respectively. The micafungin exposures associated with efficacy were similar for the two Candida species. Furthermore, the free drug micafungin exposures required to produce stasis and killing endpoints were similar to those recently reported for another echinocandin, anidulafungin, against the identical Candida isolates in this model.

Topics: Animals; Antifungal Agents; Candida albicans; Candida glabrata; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Echinocandins; Female; Lipopeptides; Micafungin; Mice; Mice, Inbred ICR; Neutropenia

In a neutropenic murine model of invasive pulmonary aspergillosis, prophylaxis with single doses of liposomal amphotericin B or micafungin at >or=5 mg/kg of body weight improved animal survival and suppressed the lung fungal burden for up to 7 days after infection, demonstrating the potential utility of infrequent dosing with these antifungals.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Colony Count, Microbial; Disease Models, Animal; Drug Administration Schedule; Echinocandins; Female; Invasive Pulmonary Aspergillosis; Lipopeptides; Liposomes; Micafungin; Mice; Mice, Inbred BALB C; Neutropenia

The treatment, diagnosis and therapeutic monitoring of hematogenous Candida meningoencephalitis (HCME) are not well understood. We therefore studied the expression of (1-->3)-beta-D-glucan (beta-glucan) in cerebrospinal fluid (CSF) and plasma in a nonneutropenic rabbit model of experimental HCME treated with micafungin and amphotericin B. Groups studied consisted of micafungin (0.5 to 32 mg/kg) and amphotericin B (1 mg/kg) treatment groups and the untreated controls (UC). Despite well-established infection in the cerebrum, cerebellum, choroid, vitreous humor (10(2) to 10(3) CFU/ml), spinal cord, and meninges (10 to 10(2) CFU/g), only 8.1% of UC CSF cultures were positive. By comparison, all 25 UC CSF samples tested for beta-glucan were positive (755 to 7,750 pg/ml) (P < 0.001). The therapeutic response in CNS tissue was site dependent, with significant decreases of the fungal burden in the cerebrum and cerebellum starting at 8 mg/kg, in the meninges at 2 mg/kg, and in the vitreous humor at 4 mg/kg. A dosage of 24 mg/kg was required to achieve a significant effect in the spinal cord and choroid. Clearance of Candida albicans from blood cultures was not predictive of eradication of organisms from the CNS; conversely, beta-glucan levels in CSF were predictive of the therapeutic response. A significant decrease of beta-glucan concentrations in CSF, in comparison to that for UC, started at 0.5 mg/kg (P < 0.001). Levels of plasma beta-glucan were lower than levels in simultaneously obtained CSF (P < 0.05). CSF beta-glucan levels correlated in a dose-dependent pattern with therapeutic responses and with Candida infection in cerebral tissue (r = 0.842). Micafungin demonstrated dose-dependent and site-dependent activity against HCME. CSF beta-glucan may be a useful biomarker for detection and monitoring of therapeutic response in HCME.

Topics: Amphotericin B; Animals; Antifungal Agents; beta-Glucans; Biomarkers; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Monitoring; Echinocandins; Female; Lipopeptides; Meningitis, Fungal; Meningoencephalitis; Micafungin; Rabbits

Hematogenous Candida meningoencephalitis (HCME) is a relatively frequent manifestation of disseminated candidiasis in neonates and is associated with significant mortality and neurodevelopmental abnormalities. The outcome after antifungal therapy is often suboptimal, with few therapeutic options. Limited clinical data suggest that echinocandins may have role to play in the treatment of HCME.. We studied the pharmacokinetics and pharmacodynamics of micafungin in a rabbit model of neonatal HCME and bridged the results to neonates by use of population pharmacokinetics and Monte Carlo simulation.. Micafungin exhibited linear plasma pharmacokinetics in the range of 0.25-16 mg/kg. Micafungin penetrated most compartments of the central nervous system (CNS), but only with doses >2 mg/kg. Micafungin was not reliably found in cerebrospinal fluid. With few exceptions, drug penetration into the various CNS subcompartments was not statistically different between infected and noninfected rabbits. A dose-microbiological response relationship was apparent in the brain, and near-maximal effect was apparent with doses of 8 mg/kg. Monte Carlo simulations revealed that near-maximal antifungal effect was attained at human neonatal doses of 12-15 mg/kg.. These results provide a foundation for clinical trials of micafungin in neonates with HCME and a model for antimicrobial bridging studies from bench to bedside in pediatric patients.

Topics: Animals; Antifungal Agents; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Echinocandins; Female; Humans; Infant, Newborn; Lipopeptides; Lipoproteins; Meningoencephalitis; Micafungin; Microbial Sensitivity Tests; Monte Carlo Method; Rabbits

We previously found that caspofungin synergized with amphotericin B lipid complex in treating murine mucormycosis. We now report a similarly enhanced activity of liposomal amphotericin combined with micafungin or anidulafungin in mice with disseminated mucormycosis. The efficacy of combination echinocandin-polyene therapy for mucormycosis is a class effect.

Topics: Amphotericin B; Anidulafungin; Animals; Antifungal Agents; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Humans; Lipopeptides; Lipoproteins; Liposomes; Male; Micafungin; Mice; Mice, Inbred BALB C; Mucormycosis; Polyenes; Rhizopus; Treatment Outcome

In a murine model of blastoschizomycosis, amphotericin B combined with micafungin, flucytosine or voriconazole did not improve the efficacy of fluconazole. However, such combinations can constitute therapeutic options for those cases where fluconazole fails.

Topics: Amphotericin B; Animals; Antifungal Agents; Colony Count, Microbial; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Echinocandins; Flucytosine; Geotrichosis; Geotrichum; Humans; Immunocompromised Host; Lipopeptides; Lipoproteins; Male; Micafungin; Mice; Mice, Inbred Strains; Microbial Sensitivity Tests; Mycoses; Peptides, Cyclic; Pyrimidines; Survival Analysis; Triazoles; Trichosporon; Voriconazole

Disseminated candidiasis is associated with a high rate of morbidity and mortality. The presence of neutrophils and the timely administration of antifungal agents are likely to be critical factors for a favorable therapeutic outcome of this syndrome. The effect of neutropenia on the temporal profile of the burden of Candida albicans in untreated mice and those treated with amphotericin B was determined using a pharmacodynamic model of disseminated candidiasis. A mathematical model was developed to describe the rate and extent of the C. albicans killing attributable to neutrophils and to amphotericin B. The consequences of a delay in the administration of amphotericin B, flucytosine, or micafungin were studied by defining dose-response relationships. Neutrophils caused a logarithmic decline in fungal burden in treated and untreated mice. The combination of amphotericin B and neutrophils resulted in a high rate of Candida killing and a sustained anti-C. albicans effect. In neutropenic mice, 5 mg/kg of body weight of amphotericin B was required to prevent progressive logarithmic growth. An increased delay in drug administration resulted in a reduction in the maximum effect to a point at which no drug effect could be observed. Neutrophils and the timely initiation of antifungal agents are critical determinants in the treatment of experimental disseminated candidiasis.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Candidiasis; Disease Models, Animal; Dose-Response Relationship, Drug; Echinocandins; Flucytosine; Kidney; Lipopeptides; Lipoproteins; Male; Micafungin; Mice; Microbial Sensitivity Tests; Neutropenia; Neutrophils; Peptides, Cyclic; Time Factors

To evaluate the efficacy of subconjunctival injection of micafungin in the treatment of experimental Candida albicans keratitis in rabbits compared with fluconazole.. In 1 eye of 24 New Zealand white rabbits, C. albicans (5 x 10 yeast cells) was inoculated in the corneal stroma. The animals were randomly assigned to 3 groups and received subconjunctival injection of 0.5 mL of 0.1% micafungin, 0.2% fluconazole, or physiologic saline once a day for 3 weeks. The eyes were examined slit-lamp biomicroscopically and histopathologically. The clinical course of fungal keratitis was compared among the 3 groups. In another 36 rabbits, a microbiological examination was performed using a quantitative isolate recovery technique, and the numbers of colony-forming units were compared among groups.. The clinical scores were significantly lower in the micafungin group than in the other 2 groups throughout the study period (P < 0.0001 approximately P = 0.0027, Bonferroni multiple comparison). The fluconazole group showed significantly lower clinical scores than the saline group on day 18 (P = 0.0343). At the end of the study period, there were significant differences between the saline and micafungin groups (P < 0.0001), the saline and fluconazole groups (P = 0.0072), and the fluconazole and micafungin groups (P = 0.0013). Histopathologically, similar results were obtained. Moreover, the results of the microbiological examination nearly matched the clinical and histopathologic findings.. Subconjunctival administration of micafungin was effective in the treatment of experimental Candida keratitis. Local application of micafungin to the eye would be a feasible treatment option for clinical fungal keratitis.

Topics: Animals; Antifungal Agents; Candidiasis; Conjunctiva; Disease Models, Animal; Echinocandins; Eye Infections, Fungal; Fluconazole; Injections; Keratitis; Lipopeptides; Lipoproteins; Male; Micafungin; Peptides, Cyclic; Rabbits

Mortality from invasive pulmonary aspergillosis approaches 80% with few useful therapeutic options available. In these studies, we examined the efficacy of micafungin (MICA) alone or in combination with other antifungals in a model of pulmonary aspergillosis in immunosuppressed DBA/2 mice infected intranasally with conidia of Aspergillus fumigatus 10AF. In the initial study, groups of mice were given saline, or 1, 3 or 10 mg kg(-1) of MICA b.i.d., s.c. All saline controls, and 90% of untreated mice succumbed to infection. The efficacy of MICA was difficult to assess because of an apparent toxicity at 10 mg kg(-1). MICA given at 1 mg/kg significantly prolonged survival over the saline controls (P = 0.008). MICA at 3 or 10 mg kg(-1) versus the saline controls approached significance. No treatment regimen differed in efficacy. The efficacy of combination therapy was assessed, with mice given either no treatment, MICA at 1 mg/kg/dose, 0.8 mg kg(-1) of intravenous amphotericin B (AMB), 100 mg kg(-1) of oral itraconazole (ICZ), or 100 mg/kg/dose of twice-daily subcutaneous nikkomycin Z (NIK). AMB alone and MICA + AMB or MICA +NIK significantly prolonged survival (P < 0.05 - 0.02) over that of the controls. ICZ alone, ICZ+MICA and NIK alone did not significantly prolong survival. MICA alone at 1 mg/kg approached significance in prolonging survival. The combination of MICA and ICZ appeared to be potentially antagonistic. Although AMB+MICA was efficacious, no synergistic activity was noted for any of the regimens. Overall, these results indicate that MICA has moderate activity against pulmonary aspergillosis and might be useful in combination with conventional AMB.

Topics: Aminoglycosides; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Drug Antagonism; Drug Therapy, Combination; Echinocandins; Female; Immunosuppression Therapy; Itraconazole; Lipopeptides; Lipoproteins; Lung Diseases, Fungal; Micafungin; Mice; Mice, Inbred DBA; Peptides, Cyclic; Survival Analysis

To develop proper treatments for patients who do not respond to current antifungal treatments, we tested new combinations of antifungal drugs for treating disseminated infections by Candida glabrata in a murine model.. Mice were rendered neutropenic by intraperitoneal cyclophosphamide and intravenous 5-fluorouracil administration. The animals were infected intravenously with 2 x 10(8) cfu of C. glabrata. The efficacies of micafungin combined with amphotericin B, fluconazole or flucytosine, and of amphotericin B combined with fluconazole were evaluated by survival and tissue burden reduction.. Micafungin plus amphotericin B was the most effective combination at reducing tissue burden. Micafungin at 10 mg/kg combined with amphotericin B at 0.75, 1.5 or 3 mg/kg prolonged survival with respect to the monotherapies, but only the second combination showed a synergistic effect in reducing fungal load in spleen and kidney. Amphotericin B at 1.5 mg/kg combined with micafungin at 5, 10 or 20 mg/kg reduced tissue burden with respect to the monotherapies, but the effects of the three combinations were very similar. These results suggest that amphotericin B in combination with micafungin is promising for the treatment of disseminated C. glabrata infections.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida glabrata; Candidiasis; Colony Count, Microbial; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Echinocandins; Fluconazole; Flucytosine; Immunocompromised Host; Kidney; Lipopeptides; Lipoproteins; Micafungin; Mice; Peptides, Cyclic; Spleen; Survival Analysis

We performed a scanning and transmission electron microscopic study on the efficacy of micafungin (MCFG) to understand what kind of damage MCFG causes to Aspergillus and to confirm its previously reported in vitro killing activity against Aspergillus in a mouse model of pulmonary aspergillosis. Aspergillus hyphae in MCFG-treated mice displayed hyphal burst, evidenced as either flattened or atrophied appearance and leakage of cellular contents after collapse of the cell wall. Thus, MCFG can induce the destruction of Aspergillus hyphae at the focus of infection. The results of the present study indicate that MCFG improves pulmonary aspergillosis due to lethal damage to Aspergillus hyphae. This action can effectively reduce the invasive ability of Aspergillus even though MCFG does not sterilize the fungal burden.

Topics: Animals; Antifungal Agents; Aspergillosis, Allergic Bronchopulmonary; Aspergillus; Disease Models, Animal; Echinocandins; Lipopeptides; Lipoproteins; Micafungin; Mice; Peptides, Cyclic

This study was conducted to evaluate the effectiveness of a new antifungal drug, micafungin, and standard antifungal drugs against endophthalmitis induced in a rabbit by intravitreal injection of Aspergillus fumigatus, an important fungal pathogen. Effectiveness was evaluated by the preservation of b-wave amplitude at 72 h after injection of the fungus relative to the b-wave amplitude at baseline before any intravitreal injections. A 0.06 ml inoculum of 10(6) conidia of A. fumigatus was injected into the vitreous of the right eye of all rabbits; and, 12 h later, a 0.06 ml solution containing one of 3 antifungal drugs or saline was injected into the vitreous of both eyes. All three antifungal drugs produced significant b-wave preservation at 72 h in infected eyes compared to that in infected eyes receiving saline injections. There was no statistically significant difference between the effects of micafungin and amphotericin B in the right eyes with fungal endophthalmitis, and both produced significantly more preservation of b-wave amplitude than voriconazole. Amphotericin B, but neither micafungin nor voriconazole produced significant reduction of the b-wave amplitude in the left eyes.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Echinocandins; Electroretinography; Endophthalmitis; Eye Infections, Fungal; Follow-Up Studies; Lipopeptides; Lipoproteins; Micafungin; Ophthalmoscopy; Peptides, Cyclic; Pyrimidines; Rabbits; Retina; Triazoles; Vitreous Body; Voriconazole

Central nervous system (CNS) aspergillosis is a severe disease that responds poorly to current therapies. The current studies examined the efficacies of several antifungal agents alone or in combination with a murine model of CNS aspergillosis. Immunosuppressed mice were infected intracerebrally with Aspergillus fumigatus and treated with an amphotericin B preparation, an echinocandin, or voriconazole (VCZ) given alone or in combination. Monotherapy studies showed that micafungin (MICA), caspofungin (CAS), VCZ, conventional amphotericin B (AMB), Abelcet (ABLC) (a lipid-carried AMB formulation; Enzon Pharmaceuticals, Inc.), and AmBisome (AmBi) (liposomal AMB; Gilead Sciences, Inc.) were efficacious. However, doses of AmBi above 15 mg/kg of body weight showed reduced efficacy. Neither MICA nor CAS showed dose responsiveness at the doses tested (1, 5, or 10 mg/kg). Only the 40-mg/kg dose of VCZ was effective. AmBi and ABLC showed dose responsiveness, with 10-mg/kg doses causing a significant reduction in fungal burden; they had equivalent activities at the 10-mg/kg dose. Suboptimal dosages of AmBi in combination with MICA, CAS, or VCZ were effective in prolonging survival. However, significantly enhanced activity was demonstrated only with AmBi and VCZ in combination. AmBi in combination with MICA or CAS showed a trend toward enhanced activity, but the combination was not significantly superior to monotherapy. The use of AmBi with CAS or VCZ at optimal doses did not improve efficacy. Cure was not attained with any dosage combinations. These results indicate that AmBi in combination with VCZ may be superior for treatment of CNS aspergillosis; combinations of AmBi and MICA or CAS were not antagonistic and may have a slight benefit.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Caspofungin; Central Nervous System Fungal Infections; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Echinocandins; Lipopeptides; Lipoproteins; Liposomes; Micafungin; Mice; Peptides, Cyclic; Pyrimidines; Triazoles; Voriconazole

While Candida albicans remains the most common Candida isolate, Candida glabrata accounts for approximately 15 to 20% of all Candida infections in the United States. In this study we used immunosuppressed mice infected with C. glabrata to investigate the efficacy of liposomal amphotericin B alone or in combination with the echinocandin caspofungin or micafungin. For monotherapy, mice were given six daily doses of liposomal amphotericin B (3 to 20 mg/kg of body weight), caspofungin (1 to 5 mg/kg), or micafungin (2.5 to 10 mg/kg). With concomitant therapy, mice received liposomal amphotericin B (7.5 mg/kg) in addition to caspofungin (2.5 mg/kg) or micafungin (2.5 mg/kg) for 6 days. For sequential therapy, liposomal amphotericin B was administered on days 1 to 3 and caspofungin or micafungin was given on days 4 to 6; conversely, caspofungin or micafungin was administered on days 1 to 3 and liposomal amphotericin B was given on days 4 to 6. Efficacy was based on the number of CFU per gram of kidney 21 days postchallenge. Monotherapy with liposomal amphotericin B (7.5 to 20 mg/kg) was significantly more effective than no drug treatment (control group) (P < 0.05) and demonstrated a dose-dependent response, with 20 mg/kg lowering the CFU/g from 6.3 to 4.2 (significantly different from the value for the control group [P < 0.001]). Monotherapy with all echinocandin doses lowered the CFU/g from 6.0 to 6.4 to 2.7 to 3.3 (significantly different from the value for the control group [P < 0.001]) with no dose-dependent response. Complete clearance of infection could be achieved only when liposomal amphotericin B was given either concomitantly with caspofungin or micafungin or if liposomal amphotericin B was given sequentially with caspofungin. In conclusion, the combination of liposomal amphotericin B with an echinocandin markedly improved the therapeutic outcome in murine C. glabrata systemic infection.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida; Candidiasis; Caspofungin; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Immunocompromised Host; Lipopeptides; Lipoproteins; Liposomes; Micafungin; Mice; Peptides, Cyclic

The efficacy of voriconazole in combination with amphotericin B or micafungin was studied in a transiently neutropenic guinea-pig model of invasive pulmonary aspergillosis. Guinea-pigs treated with the antifungal drugs, alone or in two-drug combinations, had an improved survival rate and reduced fungal burden in the lungs compared to untreated control animals. The efficacy of monotherapy and combination therapy was similar; activity was neither enhanced nor reduced with the two-drug combinations. Further studies of efficacy, dosing and optimal regimens for antifungal combinations are warranted.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Colony Count, Microbial; Disease Models, Animal; Drug Therapy, Combination; Echinocandins; Female; Guinea Pigs; Lipopeptides; Lipoproteins; Lung; Lung Diseases, Fungal; Micafungin; Peptides, Cyclic; Pyrimidines; Survival Analysis; Triazoles; Voriconazole

Invasive pulmonary aspergillosis is an important cause of morbidity and mortality in immunocompromised patients. Simultaneous inhibition of fungal cell-wall and cell-membrane biosynthesis may result in synergistic interaction against Aspergillus fumigatus. We studied the antifungal activity of micafungin, a new echinocandin, in combination with ravuconazole, a second-generation triazole, against experimental invasive pulmonary aspergillosis in persistently neutropenic rabbits. This combination led to significant reductions in mortality (P

Topics: Animals; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Echinocandins; Female; Lipopeptides; Lipoproteins; Lung; Lung Diseases, Fungal; Micafungin; Organ Size; Peptides, Cyclic; Rabbits; Thiazoles; Triazoles

Micafungin is a new echinocandin with broad-spectrum in vitro and in vivo antifungal activity against both Aspergillus and Candida species. We compared the activity of micafungin with that of amphotericin B and fluconazole in a persistently immunocompromised murine model of disseminated candidiasis against a strain of Candida tropicalis that was resistant to amphotericin B and fluconazole in vitro. Mice were rendered persistently neutropenic with multiple doses of cyclophosphamide and infected intravenously with C. tropicalis. Mice were treated with either intraperitoneal amphotericin B (0.5-5 mg/kg per dose), oral fluconazole (50 mg/kg twice a day), intravenous micafungin (1-10 mg/kg per dose) or solvent control for 7 days. Mice were killed at 11 days post-infection and kidneys, lungs, brain and liver removed for quantitative culture. Overall mortality in the model was low, with rates varying between 10% and 25% in treatment groups. Micafungin at doses between 2 and 10 mg/kg were the only regimes able to reduce cfu below the level of detection of tissues infected with C. tropicalis. Micafungin was well tolerated by the mice and was much more effective than amphotericin B or fluconazole against an amphotericin B- and fluconazole-resistant C. tropicalis.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida tropicalis; Candidiasis; Disease Models, Animal; Echinocandins; Lipopeptides; Lipoproteins; Male; Micafungin; Mice; Neutropenia; Peptides, Cyclic

The prophylactic effect of FK463, a new water-soluble echinocandin-like lipopeptide with inhibitory activity against 1, 3-beta-D-glucan synthase, against Pneumocystis carinii infection was investigated with the severe combined immunodeficient (SCID) mouse model. Treatment with FK463, pentamidine, and saline only was performed for 6 weeks from the day after the SCID mice were inoculated intranasally with infected lung homogenates. FK463 at 0.2 or 1.0 mg/kg of body weight, pentamidine at 4 mg/kg, or saline was subcutaneously administered daily into the backs of the SCID mice. The effects of the drugs were evaluated by detection of P. carinii cysts in mouse lung homogenates by toluidine blue O staining, lung histology, and PCR amplification of a P. carinii-specific DNA fragment from the lungs. P. carinii cysts were detected in the lungs of all mice administered saline. In contrast, no cysts were detected in mice administered both doses of FK463 and pentamidine. A specific DNA fragment was amplified from all mice administered saline and at least half or more of the mice administered FK463 and pentamidine. These results indicate that FK463 acts on cyst wall formation but not on trophozoite proliferation and is extremely effective in preventing P. carinii-associated pneumonia. These results suggest that FK463 is potentially useful as a prophylactic agent against P. carinii infection.

Topics: Animals; Antibiotic Prophylaxis; Antifungal Agents; Disease Models, Animal; Echinocandins; Female; Immunocompromised Host; Lipopeptides; Lipoproteins; Micafungin; Mice; Mice, SCID; Peptides, Cyclic; Pneumocystis; Pneumonia, Pneumocystis; Polymerase Chain Reaction