[Breakthrough pulmonary mucormycosis during voriconazole treatment after reduced-intensity cord blood transplantation for a patient with acute myeloid leukemia]

A 59-year-old man was admitted to our hospital with a diagnosis of acute myeloid leukemia in September 2004. He developed invasive pulmonary aspergillosis (IPA) and candidiasis, which were improved by administration of micafungin and amphotericin B (AMPH-B). He received reduced-intensity unrelated cord-blood transplantation without induction chemotherapy. He developed grade IV graft-versus-host disease (GVHD) and the administration of steroids against GVHD was prolonged. Voriconazole (VRCZ) was used for a long period to prevent recurrence of the IPA. Afterwards, infiltrates in the bilateral upper lung fields were detected on a chest CT scan, and a diagnosis of pulmonary mucormycosis was made following detection of Mucor circinelloides from the patient's sputum culture. He then began receiving AMPH-B but died of massive hemoptysis. Mucormycosis usually occurs in immunocompromised hosts such as neutropenic patients with hematologic diseases and is a fatal fungal infection characterized by a rapid and progressive clinical course. Some overseas investigators have recently reported that VRCZ prophylaxis may result in breakthrough mucormycosis in hematopoietic stem cell transplant recipients. These findings suggest that it is very important to pay attention to mucormycosis in hematopoietic stem cell transplant recipients in this country.

Combined therapies in a murine model of blastoschizomycosis

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.

Acquired resistance to echinocandins in Candida albicans: case report and review

OBJECTIVES

A patient with Candida albicans thrush and oesophagitis was treated with high doses of caspofungin but treatment eventually failed. Four C. albicans isolates were serially recovered before and after caspofungin treatment. A microbiological study was performed to characterize these four isolates.

METHODS

In vitro antifungal susceptibility testing was performed by the EUCAST reference method in RPMI and AM3 and by Etest. Molecular typing of the four isolates was done by sizing three polymorphic microsatellite markers. To look for specific mutations, sequencing of a region of the gene encoding the 1-3-beta-D-glucan synthase was performed for the four isolates.

RESULTS

In vitro antifungal susceptibility testing showed an increase in both caspofungin and micafungin MICs for the two isolates recovered after caspofungin treatment failure. The best discrimination between the pre-treatment and post-treatment isolates was obtained with Etest. Molecular typing of the four isolates showed that the post-treatment isolates with reduced susceptibility were identical to a susceptible pre-treatment isolate, suggesting the acquisition of caspofungin resistance. Sequencing of the gene encoding the 1-3-beta-D-glucan synthase showed a mutation responsible for an amino acid change at Phe-641 that could confer reduced susceptibility to both echinocandins.

CONCLUSIONS

Our results indicate that is it useful to perform in vitro susceptibility testing in the cases of clinical failure during caspofungin therapy.

Serum differentially alters the antifungal properties of echinocandin drugs

Antifungal efficacies of the echinocandin drugs caspofungin, micafungin, and anidulafungin were reduced significantly in the presence of 50% human serum, which yielded nearly equivalent MICs or minimum effective concentrations against diverse Candida spp. and Aspergillus spp. Consistent with a direct drug interaction, serum decreased the sensitivity of glucan synthase to echinocandin drugs.

Successful medical treatment of cutaneous aspergillosis in a premature infant using liposomal amphotericin B, voriconazole and micafungin

Treatment options for primary cutaneous aspergillosis in neonates are limited by the lack of pharmacokinetic and safety data of newer antifungal agents that are effective against Aspergillus spp. We report the successful treatment of cutaneous aspergillosis in an extremely low-birth-weight preterm infant with liposomal amphotericin B, voriconazole and micafungin, and provide pharmacokinetic profiles for voriconazole and micafungin.

The Echinocandins

The changing pattern in fungal infections has driven the need to expand the targets of antifungal activity. The echinocandins are the newest addition to the arsenal against fungal infections. Three echinocandins have been approved by the United States Food and Drug Administration: caspofungin, micafungin, and anidulafungin. These agents have a broad spectrum of activity and are similar to each other with respect to in vitro activity against Candida sp, with micafungin and anidulafungin having similar minimum inhibitory concentrations (MICs) that are generally lower than the MIC of capsofungin. The MICs of the echinocandins are highest against Candida parapsilosis; however, whether this will affect clinical outcomes is unknown. Several case reports have identified clinical failure due to elevated MICs with caspofungin or micafungin against Candida albicans, Candida krusei, and C. parapsilosis. Resistance to the echinocandin class was present in some but not all of the isolates. Empiric therapy with one of the echinocandins for candidemia or invasive candidiasis in patients with neutropenia and those without neutropenia appears to be appropriate when one factors in mortality rate, the increasing frequency of non-albicans Candida infections, and the broad spectrum, safety, and fungicidal effect of the echinocandins. After speciation of the organism, continued therapy with an echinocandin can and should be reevaluated. The echinocandins demonstrate similar in vitro and in vivo activity against Aspergillus sp, but only caspofungin is approved for treatment in patients who are intolerant of or refractory to other therapies. Voriconazole and amphotericin B have demonstrated synergy with the echinocandins. The clinical response to combination therapy has been variable; however, the mortality rate appears to be lower with combination therapy than monotherapy. Large controlled trials are needed to determine the role of combination therapy for invasive aspergillosis. Micafungin and anidulafungin generally have a lower frequency of adverse reactions compared with caspofungin. Phlebitis (3.5-25% of patients) and elevated liver enzyme levels (1-15%) occur more often with caspofungin compared with micafungin and anidulafungin (< 8%). Overall, the three echinocandins are relatively safe and effective agents for the treatment of Candida infections.

X-linked severe combined immunodeficiency (X-SCID) with high blood levels of immunoglobulins and Aspergillus pneumonia successfully treated with micafangin followed by unrelated cord blood stem cell transplantation

In this report, we describe a patient with X-linked severe combined immunodeficiency (X-SCID) who had high serum IgG, IgA, and IgM levels. The boy did well until 6 months of age, when he developed interstitial pneumonia caused by Aspergillus species, with a white cell count of 12,840/microL and only 10% lymphocytes; IgG, 991 mg/dL; IgA, 65 mg/dL; IgM, 472 mg/dL. Cell markers showed only 6.3% CD3, 2.1% CD4, 0.7% CD8, but 92% CD19 and 0.1% CD16+CD56+ (NK cells). A mutation was detected within exon 2 (C196 A-->C), leading to the substitution of proline for glutamine, which has not been reported previously. The boy was successfully treated with the new antifungal drug, micafangin (MCFG), at 5 mg/kg/day for 89 days. After resolution of the pneumonia, the patient underwent successful hematopoietic stem cell transplantation with completely matched unrelated female cord blood. The CD34 stem cell dose was 3.4 x 10(4) cells/kg. In conclusion, MCFG can be a first line agent for Aspergillus pneumonia in immunocompromised hosts.

Anticoagulant and antithrombotic properties of intracellular protease-activated receptor antagonists

BACKGROUND

Blockade of the thrombin receptors protease-activated receptor (PAR)1 and PAR4 with pepducins, cell-penetrating lipopeptides based on the third intracellular loop of PAR1 and PAR4, effectively inhibits platelet aggregation. We have previously shown that PAR1 pepducin also exerts an anticoagulant activity by partial inhibition of the thrombin plus collagen-induced externalization of phosphatidylserine (PS) at the platelet plasma membrane.

OBJECTIVE

In the present study we examined the effects of PAR1 and PAR4 pepducins on tissue factor (TF)-initiated thrombin generation in platelet-rich plasma (PRP) and the interaction between PAR4 pepducin-loaded mouse platelets and a growing thrombus to confirm the relevance of the in vitro data.

RESULTS

Localization of pepducins at the inner leaflet of the plasma membrane was confirmed with a fluorescence resonance energy transfer assay. Both the PAR1 pepducin, P1pal12, and the PAR4 pepducin, P4pal10, inhibited TF-initiated thrombin generation in PRP. Concentrations of P1pal12 and P4pal10, which blocked the thrombin-induced influx of extracellular calcium ions and inhibited platelet aggregation, reduced the rate of thrombin generation during the propagation phase by 38% and 36%, respectively. Whether this anticoagulant effect is relevant in inhibiting in vivo arterial thrombin growth is uncertain because P4pal10 prevented the incorporation of platelets in a growing thrombus.

CONCLUSIONS

Our findings suggest that in spite of their potential anticoagulant activities the in vivo antithrombotic effect of intracellular PAR pepducins is mainly based on inhibiting platelet-platelet interactions.

[Efficacy of micafungin sodium on fungal infection in critical care]

The clinical effects and tolerability of micafungin sodium in daily practice for the treatment of fungal infection in critically ill patients were evaluated in an open-labeled, non-comparative, observational study. All patients admitted to intensive care units (ICUs) of 3 hospitals in Chiba prefecture between June 2003 and March 2005, who were treated with micafungin because of known or suspected fungal infection, were included in the study. A total of 34 patients received micafungin and 29 cases of them were subjected to analysis. Fungal infections were classified as "proven" in 3 patients (10.3%) and "possible" in 26 (89.7%). Candida was detected in 16 patients, most of them were Candida albicans and 4 cases were non-albicans Candida. Clinical effects of micafungin were "cured" and "improved" in 20 patients (77%), "failure" in 6 (23%), and "undetermined" in 3 cases. Adverse events were reported in 10 patients, but there was no significant event. In conclusion, micafungin was effective in 77% of proven or suspected fungal infections in critically ill patients admitted to the ICU. The drug was well tolerated and discontinuation of its treatment due to adverse events was not experienced during the study period.

Impact of Pharmacometric Reviews on New Drug Approval and Labeling Decisions—a Survey of 31 New Drug Applications Submitted Between 2005 and 2006

Exploratory analyses of data pertaining to pharmacokinetic, pharmacodynamic, and disease progression are often referred to as the pharmacometrics (PM) analyses. The objective of the current report is to assess the role of PM, at the Food and Drug Administration (FDA), in drug approval and labeling decisions. We surveyed the impact of PM analyses on New Drug Applications (NDAs) reviewed over 15 months in 2005-2006. The survey focused on both the approval and labeling decisions through four perspectives: clinical pharmacology primary reviewer, their team leader, the clinical team member, and the PM reviewer. A total of 31 NDAs included a PM review component. Review of NDAs involved independent quantitative evaluation by FDA pharmacometricians. PM analyses were ranked as important in regulatory decision making in over 85% of the 31 NDAs. Case studies are presented to demonstrate the applications of PM analysis.

Therapeutic vaccination in chronic hepatitis B virus carriers

Despite effective prophylactic vaccines against hepatitis B virus existing for over 20 years, more than 2.5 billion people worldwide have been exposed to the disease and approximately 370 million people are chronically infected with it. Chronic infection in more than two thirds of infected patients results in chronic liver disease, which may lead to cirrhosis, exposure to noncarcinomatous complications and hepatocellular carcinoma. Currently available therapies fail to allow complete control of viral replication in most patients. Viral persistence has been associated with a defect in the development of hepatitis B virus-specific cellular immunity. Immunomodulatory strategies to boost or to broaden the weak virus-specific T-cell response have been proposed to bypass the chronic hepatitis B infection, including hepatitis B virus envelope- and nucleocapsid-based vaccines, and new formulations for recombinant and DNA-based vaccines, which are currently being evaluated in clinical trials.

Efficacy of aminocandin in the treatment of immunocompetent mice with haematogenously disseminated fluconazole-resistant candidiasis

OBJECTIVES

The objective of this study was to compare the activity of aminocandin, a new echinocandin with broad-spectrum activity against Candida spp., with that of amphotericin B, caspofungin and fluconazole, in an immunocompetent murine model of haematogenously disseminated candidiasis caused by a fluconazole-resistant Candida albicans.

METHODS

Mice were infected with a fluconazole-resistant strain of C. albicans and treated with aminocandin 5 and 10 mg/kg intravenously (iv) once and twice weekly, amphotericin B 0.5 mg/kg iv every other day for 5 days, fluconazole 20 mg/kg orally (po) once a day for 5 days and caspofungin 0.5 mg/kg intraperitoneally (ip) once daily for 5 days.

RESULTS

Treatment with aminocandin, given iv twice a week, resulted in 100% survival. Further, the tissue fungal burden of the aminocandin group was equivalent to that of amphotericin B (administered every other day) and caspofungin (administered daily).

CONCLUSIONS

Aminocandin may be an effective addition to the arsenal of antifungal compounds for the treatment of candidiasis caused by fluconazole-resistant C. albicans.

Micafungin: A New Echinocandin Antifungal

The echinocandins represent the newest class of antifungals to combat infections caused by Candida sp. Micafungin is an echinocandin recently approved by the United States Food and Drug Administration. It is indicated in adults for esophageal candidiasis and prophylaxis against candidal infections in hematopoietic stem cell transplant recipients. Micafungin exhibits in vitro fungicidal activity against Candida sp, including fluconazole-resistant isolates. Its in vivo efficacy is comparable to that of fluconazole in the treatment of esophageal candidiasis and superior to that of fluconazole for prophylaxis of invasive candidal infections. Because it is not significantly metabolized by the cytochrome P450 3A system, micafungin is associated with few drug interactions. Micafungin does not require adjustment in patients with renal and/or hepatic impairment, and it has been shown to be well tolerated in both adult and pediatric patients. Its efficacy against Candida sp, coupled with its overall safety and drug interaction profiles, makes it an attractive option in the treatment against esophageal candidiasis and prophylaxis against invasive candidal infections.

Successful treatment of refractory chronic necrotizing pulmonary aspergillosis with micafungin

A 63-year-old man was admitted to our hospital because he complained of fever and productive cough; this was associated with cavitary infiltrates on his chest X-ray. Although several antibiotics were given, his symptoms did not improve. Bronchofiberscope investigation yielded Aspergillus fumigatus; thus, he was diagnosed with chronic necrotizing pulmonary aspergillosis. Itraconazole, 200 mg/day, was given, and his symptoms and infiltrates on chest X-ray gradually improved. After 2 months of treatment, new infiltrates appeared on a chest X-ray. Antibacterial agents had also shown no effect, and voriconazole was substituted for itraconazole. However, the infiltrates progressed in spite of the voriconazole administration. We added micafungin to the voriconazole treatment. Both his symptoms and the infiltrates on chest X-rays improved. Because voriconazole is thought to be the most effective agent against Aspergillus spp., it is difficult to treat cases that are refractory to voriconazole. The treatment of this case provides invaluable information on how to treat pulmonary aspergillosis related to diseases other than hematologic malignancies.

Clinical efficacy of micafungin for chronic pulmonary aspergillosis

The rising incidence of pulmonary aspergillosis is a major clinical concern. However, only a limited number of antifungal drugs are available in Japan that are effective for pulmonary Aspergillus infections. Micafungin (MCFG), a newly developed echinocandin family antifungal drug, has potent antifungal activity in vitro, but few reports detailing its clinical effectiveness have been published to date. A retrospective study was performed using data from nine patients (seven males and two females) with chronic invasive forms of pulmonary aspergillosis, who were treated with either MCFG alone or together with other antifungal drugs between April 2003 and March 2004. The overall efficacy of the treatments was evaluated in the terms of clinical, mycological, serological and radiological responses. The average age of the patients was 61.9 (20-83) years old. Four patients received only MCFG and the remaining five patients were treated with MCFG in combination with amphotericin B (AMB) only (1 patient), itraconazole (ITC) only (2 patients) or AMB backed up by ITC during AMB discontinuation periods (2 patients). The mean duration of MCFG administration was 59.2 (28-96) days. Overall, the treatment was judged to have been effective for seven of nine patients. No patient's condition deteriorated in response to treatment. Administration of MCFG alone was judged to have been effective in three of four patients. No notable adverse effects were documented during MCFG administration. These data suggest that MCFG may be an effective and safe antifungal drug for the treatment of chronic invasive forms of pulmonary aspergillosis.

Effect of neutropenia and treatment delay on the response to antifungal agents in experimental disseminated candidiasis

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.

Efficacy and safety of micafungin in febrile neutropenic patients treated for hematological malignancies

OBJECTIVE

The purpose of this study was to prospectively evaluate the efficacy and safety of micafungin (MCFG) in empirical therapy for febrile neutropenic patients for whom antibiotic therapy was not effective for hematological malignancies.

PATIENTS AND METHODS

Twenty-three hematological patients aged 27-82 years with febrile neutropenia for whom antibiotic therapy was not effective were enrolled in this study and responses to treatment were evaluated.

RESULTS

Treatment success rate was 73.9%. Treatment success rates by primary diagnosis were 77.8% in patients with AML, 50.0% in patients with NHL and 87.5% in patients with other diseases. Moreover, MCFG at a dose of 100 mg or more have a tendency to be effective. One or more adverse events occurred in five (27.7%) of the patients during the study. All of these adverse events were below grade 2 toxicity.

CONCLUSIONS

Although the number of patients studied was limited, MCFG as a monotherapy seems to be effective and safe as an empirical therapy in patients with febrile neutropenia. However, further investigation using large-scale studies is needed. This study demonstrated the clinical efficacy and safety of MCFG in patients with febrile neutropenia and with hematological malignancies.

Invasive pulmonary aspergillosis with hematological malignancy caused by Aspergillus terreus and in vitro susceptibility of A. terreus isolate to micafungin

A 35-year-old man developed invasive pulmonary aspergillosis (IPA) with severe neutropenia after umbilical cord stem cell transplantation for chronic myelogenous leukemia. Filamentous fungus isolated from his sputum was identified as Aspergillus terreus. Despite systemic amphotericin B (AMPH) administration, IPA progressed. However, intravenous administration of micafungin (MCFG) and oral itraconazole improved clinical data and symptoms, although he later died of massive hemoptysis. Examination of the in vitro susceptibility of this A. terreus isolate to MCFG revealed a good minimum inhibitory concentration and good time-kill assay results compared to AMPH. Thus, MCFG might be useful for IPA caused by A. terreus.

Once-weekly micafungin therapy is as effective as daily therapy for disseminated candidiasis in mice with persistent neutropenia

The effect of micafungin dose scheduling on the treatment of candidemia is unknown. Neutropenic mice with disseminated Candida glabrata infection were treated with single intraperitoneal micafungin doses of 0 to 100 mg/kg of body weight and sacrificed 7 days later. The maximal decline in kidney fungal burden was 5.8 log(10) CFU/g. A 1-week pharmacokinetic-pharmacodynamic study revealed a micafungin serum half-life of 6.13 h. In mice treated with > or =50 mg/kg, there was maximal fungal decline without regrowth during the 1-week dosing interval. Next, doses associated with 34% (34% effective dose [ED(34)]) and 50% (ED(50)) of maximal kill were administered at one of three dose schedules: a single dose at t = 0, two equal doses at t = 0 and t = 3.5 days, and 7 equal doses daily. Some mice received a single dose of 100 mg/kg. Fungal burden was examined on days 1, 5, and 7. In mice treated with the ED(34), microbial kill with the daily therapy initially lagged behind the intermittent doses but exceeded it by day 7. In mice treated with the ED(50), daily and intermittent doses had equivalent day 7 effects. In mice treated with 100 mg/kg, there was no regrowth. The relative likelihoods that the area under the concentration-time curve/MIC ratio was linked to microbial kill versus peak concentration/MIC ratio or time above the MIC was 10.3 and 10,161.2, respectively. In all the experiments, no paradoxical increase in fungal burden was observed with high micafungin doses. However, only a single Candida isolate was tested. Regimens that simulated micafungin concentration-time profiles in patients treated with a single micafungin dose of 1,400 mg once a week demonstrated maximal fungal decline. Once-weekly micafungin therapy is as efficacious as daily therapy in a murine model of disseminated candidiasis.

Effects of Hepatic CYP3A4 Activity on Disposition of Micafungin in Liver Transplant Recipients With Markedly Small-for-Size Grafts

Micafungin, the first candin antifungal drug developed in Japan, has a significant therapeutic effect against deep-seated mycoses caused by Candida or Aspergillus. Little is known, however, about the optimal dosage or disposition of micafungin in patients with severe hepatic impairment. Nine liver transplant recipients (5 males and 4 females) were enrolled in this study. In 1 recipient with a markedly small-for-size graft (ratio of graft volume to standard liver volume at the time of transplantation: 25.9%), the areas under the plasma concentration-time curves up to 12 hours postdose (AUC(0-12 h)) at doses of 50 and 100 mg/d were 79.38 and 601.17 mug.h/mL, respectively. The corresponding elimination half-life (T(1/2)) values were 16.01 and 75.75 hours, and saturated elimination was observed only at the dose of 100 mg/d. The mean urinary ratio of 6beta-hydroxycortisol to cortisol (6beta-OHF/F) in the small-for-size graft recipient was significantly (P < .05) lower than that in the other recipients. In conclusion, graft size was an important factor affecting disposition of micafungin. For liver transplant recipients with markedly small-for-size grafts, the optimal dosage of micafungin to reach and maintain therapeutic plasma levels is estimated to be 50 mg/d.

Emerging drugs for the treatment of sepsis

Septic shock still places a major burden on the healthcare system, although recent years have been marked by the demonstration that corticosteroids and activated protein C may substantially improve survival in selected populations. This review discusses the current management of septic shock and the potential development of new therapeutics following impressive advances in the pathomechanisms of septic shock.

[Hepatitis B vaccine improvement]

Data about ongoing researches in order to increase efficacy and immunogenicity of licensed hepatitis B vaccines and to develop new therapeutic vaccines for chronic hepatitis B treatment are reviewed.

Echinocandins in the management of invasive fungal infections, part 2

PURPOSE

The chemistry, pharmacology, spectrum of activity, resistance, pharmacokinetics, pharmacodynamics, clinical efficacy, adverse effects, drug interactions, dosage and administration, cost, and place in therapy of echinocandins are reviewed.

SUMMARY

Three echinocandins are currently available: caspofungin, micafungin, and anidulafungin. The principal mechanism of action of the echinocandins is the noncompetitive inhibition of beta-(1,3)-D-glucan synthase, an essential component of the cell wall of many fungi that is not present in mammalian cells. Echinocandins exhibit fungicidal activity against Candida species, including triazole-resistant isolates, and fungistatic activity against Aspergillus species. While fungistatic against mold, echinocandins may hold promise for the treatment of these pathogens when given in combination with amphotericin B or broad-spectrum triazoles, such as voriconazole. To date, resistance to echinocandins has been reported in only two patients. Echinocandins exhibit concentration-dependent activity against Candida species. In clinical trials, caspofungin has demonstrated efficacy in treating candidemia, esophageal candidiasis, and febrile neutropenia. Micafungin has demonstrated efficacy as antifungal prophylaxis in hematopoietic stem cell transplant recipients and in the treatment of esophageal candidiasis. Anidulafungin received approved labeling from the Food and Drug Administration in February 2006. Clinical efficacy data will be forthcoming.

CONCLUSION

Echinocandins are fungicidal against yeast and fungistatic against mold. Their limited toxicity profile and minimal drug-drug interactions make them an attractive new option for the treatment of invasive fungal infections. Their cost may limit their use as initial therapy for patients with fungemia in medical centers or intensive care units with a high rate of triazoleresistant Candida infections.

Combined antifungal therapy in a murine infection by Candida glabrata

OBJECTIVES

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.

METHODS

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.

RESULTS AND CONCLUSIONS

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.

Candida glabrata fungemia in a diabetic patient with neurogenic bladder: successful treatment with micafungin

A 69-year-old man was transferred to our hospital because of fever and acute renal failure. 5 weeks prior to admission, he was admitted to another hospital and treated with several antibiotics including vancomycin, but fever did not subside and renal dysfunction showed rapid progression. On admission, laboratory findings revealed pyuria, inflammatory changes, acute renal failure, and disseminated intravascular coagulation (DIC). Computed tomography showed left ureteral stone and hydronephrosis. Gallium scintigraphy showed avid uptake in the left kidney. Serum concentration of vancomycin was 57.4 micro/ml. Candida glabrata was isolated from blood, sputum and urine. Under the diagnosis of fungemia and left pyelonephritis, he was treated with micafungin (150 mg/day), gabexate mesilate and insertion of a double-ended pigtail catheter. The above treatment produced regression of systemic inflammation, DIC and acute renal failure. At the last follow-up 3 weeks after discharge, ureteroscopy showed that the ureter stone had already passed but a soft white-yellowish bezoar was detected in the ureter. In this case, neurogenic bladder, poorly controlled diabetes, and long-term antibiotic treatment probably enhanced the development of C. glabrata infection. Antifungal treatment with micafungin is useful in patients with non-albicans Candida infection.

New agents for the treatment of fungal infections: clinical efficacy and gaps in coverage

The incidence of fungal infections has increased globally, and the introduction of the newer triazoles and echinocandin antifungals is a more-than-welcome and long overdue development. In this report, we review the clinical trials evaluating the therapeutic efficacy of these new antifungal agents and examine possible gaps in coverage. Voriconazole has become the primary treatment for most forms of invasive aspergillosis in a number of centers, posaconazole offers a broad antifungal spectrum, and echinocandins are fungicidal against most Candida species. Moreover, the new agents are active against some fungi that are resistant to amphotericin B, may have a role in the management of fever and neutropenia, and provide exciting options for combination antifungal therapy. However, significant questions remain, including the management of breakthrough infections and treatment failures and the efficacy of the new antifungal agents against less common fungi.

[Efficacies and clinical roles of new antifungal agents]

Micafungin, a new class of the antifungal agent "echinocandin" released in 2002, and voriconazole, a new triazole antifungal agent released in 2005 in Japan have in vitro activities against Aspergillus spp. Results of large-scale clinical trials in Europe and the United States showed voriconazole to have superior efficacy against invasive pulmonary aspergillosis in comparison with conventional amphotericin B, and caspofungin, a member of the echinocandins, was effective as an empirical antifungal therapy in patients with persistent fever and neutropenia. In this way, choices of therapeutic medicine for aspergillosis are increasing more and more, and it is expected that the method of treatment will change greatly in future. On the other hand, we need to establish a new standard therapy for aspergillosis to avoid the clinical disruption caused by the variety of pharmaceutical choice caused. In this report, we describe the role of new antifungal agents for non-fumigatus Aspergillus infections, and the breakthrough in counteracting fungal infection using these new drugs.

Successful Treatment of Breakthrough Trichosporon asahii Fungemia with Voriconazole in a Patient with Acute Myeloid Leukemia

We describe a 55-year-old man with acute myelogenous leukemia who developed breakthrough Trichosporon asahii fungemia during 5 days of micafungin treatment. Although the patient's clinical condition improved considerably after the start of voriconazole treatment, blood culture results remained positive for T. asahii for 3 days, and fever persisted for 7 days thereafter. The patient achieved complete hematological remission, and he received successful consolidation chemotherapy without developing Trichosporon infection with the prophylactic use of voriconazole therapy. This case report illustrates that voriconazole may be useful in the treatment of disseminated T. asahii infection in neutropenic patients.

Pharmacokinetics-pharmacodynamics of micafungin in Japanese patients with deep-seated mycosis

The objective of this study was to describe the pharmacokinetic profile and investigate the effective concentration of micafungin in Japanese male patients with deep-seated mycosis. 66 patients were treated with i.v. micafungin 12.5-150 mg intravenously for up to 56 days. At this dose range, micafungin showed linear pharmacokinetics, and the mean values of Cmax and Cmin amounted to 3.16-12.9 microg/mL and 0.70-3.68 microg/mL, respectively. The mean value for the elimination half-life was 13.5 h (95 samples from 65 patients), and it remained almost constant over the dose range. In addition, the elimination half-life was not influenced by age, gender or weight, and was similar to that found in healthy subjects. The active metabolites M1 and M2 were detectable, but their exposure was lower than that of the unchanged drug. The pharmacokinetic-pharmacodynamics ob micafungin were then investigated. The overall clinical response rate against aspergillosis and candidiasis showed good results at a dose of 50 mg and over. The Cmax and Cmin at the latter dose amounted to 5.16 and 1.41 microg/mL, respectively. In conclusion, micafungin showed linear pharmacokinetics at doses ranging from 12.5 to 150 mg, and the effective concentration was considered to be over 5 microg/mL as maximum level in Japanese patients with deep-seated mycosis such as candidiasis and aspergillosis.

Pharmacological inhibition of tissue factor

Tissue factor plays an essential role in the initiation of coagulation in vivo. In severe conditions, including sepsis and acute lung injury, increased expression of tissue factor may induce disseminated intravascular coagulation and fibrin deposition in organs, which are believed to have a determining impact on patient outcome. Tissue factor also acts as a signaling receptor and is involved in the systemic inflammatory response, as in cancer progression and atherosclerosis. Interventions aiming at limiting tissue factor activities have been evaluated in multiple experimental studies and the observed results have supported the potential benefits for coagulation disorders, inflammation, and survival. The effects of the main physiological inhibitor of tissue factor, tissue factor pathway inhibitor, have been evaluated in two large clinical trials in sepsis. Even though they are not associated with an improved outcome, the observed data support further clinical studies.

Micafungin (FK463), alone or in combination with other systemic antifungal agents, for the treatment of acute invasive aspergillosis

BACKGROUND

Micafungin (FK463) is a new lipopeptide compound (echinocandin) with activity against Aspergillus and Candida species. This study evaluated the safety and efficacy of micafungin in patients with proven or probable invasive aspergillosis (IA).

METHODS

A multinational, non-comparative study was conducted to examine proven or probable (pulmonary only) Aspergillus species infection in a wide variety of patient populations. The study employed an open-label design utilizing micafungin alone or in combination with another systemic antifungal agent. Criteria for IA and therapeutic responses were judged by an independent panel.

RESULTS

Of the 331 patients enrolled, only 225 met diagnostic criteria for IA as determined by the independent panel and received at least one dose of micafungin. Patients included 98/225 who had undergone hematopoietic stem cell transplantation (HSCT) (88/98 allogeneic), 48 with graft versus host disease (GVHD), and 83/225 who had received chemotherapy for hematologic malignancy. A favorable response rate at the end of therapy was seen in 35.6% (80/225) of patients. Of those only treated with micafungin, favorable responses were seen in 6/12 (50%) of the primary and 9/22 (40.9%) of the salvage therapy group, with corresponding numbers in the combination treatment groups of 5/17 (29.4%) and 60/174 (34.5%) of the primary and salvage treatment groups, respectively. Of the 326 micafungin-treated patients, 183 (56.1%) died during therapy or in the 6-week follow-up phase; 107 (58.5%) deaths were attributable to IA.

CONCLUSIONS

Micafungin as primary or salvage therapy proved efficacious and safe in high-risk patients with IA, although patient numbers are small in the micafungin-only groups.

Micafungin: a new echinocandin

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.

Breakthrough Trichosporonosis in Patients with Hematologic Malignancies Receiving Micafungin

BACKGROUND

Micafungin is a newly approved antifungal agent in the echinocandin class that is active against Candida species and Aspergillus species. However, this agent has limited activity against a number of fungi, including Trichosporon species. We describe 4 patients who developed disseminated trichosporonosis during the use of micafungin. No cases of trichosporonosis had been seen in the 2 years prior to January 2003, when micafungin became available in our hospital.

METHODS

We reviewed microbiological records of patients at Kameda General Hospital (Kamogawa City, Chiba, Japan) from 1 January 2002 to 31 July 2005, and identified 4 patients whose blood culture results were positive for Trichosporon species.

RESULTS

Since January 2003, four patients--3 with acute myelocytic leukemia and 1 with myelodysplastic syndrome--developed disseminated trichosporonosis while receiving treatment with micafungin with or without amphotericin B. The initial 2 isolates were identified as Trichosporon beigelii, and the later 2 isolates were identified as Trichosporon asahii. All 4 patients received micafungin, and 2 also received amphotericin B concomitantly. Minimal inhibitory concentrations of micafungin were >16 microg/mL for the 2 isolates available for susceptibility testing. One patient with hematologic recovery (neutrophils >500 cells/mm3) showed elimination of the fungus after receiving treatment with voriconazole. However, the 3 other patients without hematologic or immunological recovery died of disseminated infection.

CONCLUSIONS

The rarity of trichosporonosis in our hospital and its emergence after the introduction of micafungin therapy support the idea that micafungin may exert a significant, selective pressure toward resistant fungi, such as Trichosporon species. Therefore, care should be taken regarding the possibility of trichosporonosis in patients receiving micafungin with or without amphotericin B.

Treatment of Candida glabrata infection in immunosuppressed mice by using a combination of liposomal amphotericin B with caspofungin or micafungin

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.

Comparative efficacies of conventional amphotericin b, liposomal amphotericin B (AmBisome), caspofungin, micafungin, and voriconazole alone and in combination against experimental murine central nervous system aspergillosis

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.

Tissue factor pathway inhibitor: structure, biology and involvement in disease

Tissue factor (TF)-initiated coagulation plays a significant role in the pathophysiology of many diseases, including cancer and inflammation. Tissue factor pathway inhibitor (TFPI) is a plasma Kunitz-type serine protease inhibitor, which modulates initiations of coagulation induced by TF. In a factor (F) Xa-dependent feedback system, TFPI binds directly and inhibits the TF-FVII/FVIIa complex. Normally, TFPI exists in plasma both as a full-length molecule and as variably carboxy-terminal truncated forms. TFPI also circulates in complex with plasma lipoproteins. The levels and the dual inhibitor effect of TFPI on FXa and TF-FVII/FVIIa complex offers insight into the mechanisms of various pathological conditions triggered by TF. The use of selective pharmacological inhibitors has become an indispensable tool in experimental haemostasis and thrombosis research. In vivo administration of recombinant TFPI (rTFPI) in an experimental animal model prevents thrombosis (and re-thrombosis after thrombolysis), reduces mortality from E. coli-induced-septic shock, prevents fibrin deposition on subendothelial human matrix and protects against disseminated intravascular coagulation (DIC). Thus, TFPI may play an important role in modulating TF-induced thrombogenesis and it may also provide a unique therapeutic approach for prophylaxis and/or treatment of various diseases. In this review, we consider structural and biochemical aspects of the TFPI molecule and detail its inhibitory mechanisms and therapeutic implications in various disease conditions.

Progressive loss of echinocandin activity following prolonged use for treatment of Candida albicans oesophagitis

OBJECTIVES

To illustrate the progressive loss of cross-echinocandin activity on Candida albicans isolates with strong clonal homology from a patient with advanced HIV infection and chronic oesophagitis progressively resistant to uninterrupted micafungin treatment.

METHODS

Antifungal susceptibility profiles for different antifungal agents were determined against serial C. albicans isolates retrieved before and during therapy. Multilocus sequencing typing (MLST) was performed on each of the isolates. FKS1 mutations conferring reduced susceptibility to echinocandin drugs were determined by DNA sequence analysis.

RESULTS

Four C. albicans isolates showing identical allelic homology were retrieved from the patient at the initiation and during therapy with micafungin. The progressive lack of clinical response to micafungin therapy was associated with increased MICs of all three echinocandin drugs (caspofungin, micafungin and anidulafungin) in association with the acquisition of mutations in the FKS1 gene.

CONCLUSIONS

This report documents for the first time a progressive loss of activity of all three echinocandin drugs against clonally related C. albicans isolates following long-term clinical exposure to this new class of antifungal agents.

Activities of flucytosine, fluconazole, amphotericin B, and micafungin in a murine model of disseminated infection by Candida glabrata

We compared the efficacies of amphotericin B, fluconazole, flucytosine, and micafungin in a systemic murine infection by three isolates of Candida glabrata. Amphotericin B showed the best results, although none of the drugs dramatically reduced mortality or tissue burden in liver or spleen.

Successful Treatment of Invasive Sinus Aspergillosis with Micafungin and Itraconazole

BACKGROUND

We report a case of invasive sinus aspergillosis that extended to the orbital cavity and cavernous sinus and was improved by treatment with micafungin and itraconazole.

CASE REPORT

A 83-year-old woman was referred to our hospital because of headache and impaired of eye movement on the right side. Physical examination revealed impaired function of cranial nerves, II, II, IV, and VI on the right side. MRI showed evidence of inflammation of the right sphenoid sinus and ethmoidal sinus and an enhancing mass in the right cavernous sinus and orbit. Because a culture of a specimen from the right sphenoid sinus extracted during endoscopic sinus surgery, yielede Aspergillus fumigatus, a diagnosed of invasive sinus aspergillosis complicated by cavernous sinus symdrome and orbital apex symdrome was made. It was difficult to completely remove the mass in the sinuses surgically and drug therapy with micafungin was started and then itraconazole was added. The clinical manifestations and the impaired function of cranial nerves II, III, IV, and VI improved, and MRI showed regression of the mass in the sinuses temporary in response to drug therapy.

CONCLUSION

Invasive sinus aspergillosis often progresses rapidly in the absence of surgery. Our case is valuable, because invasive sinus aspergillosis was improved by drug therapy alone, and combined treatment with micafungin and itraconazole was effective.

Micafungin, a novel antifungal agent, as empirical therapy in acute leukemia patients with febrile neutropenia

OBJECTIVE

Invasive fungal infection is a major cause of morbidity and mortality in patients with febrile neutropenia unresponsive to antibacterial treatment. Empirical antifungal therapy with amphotericin B has been the standard of care for these patients; however, there remains a need for less toxic alternative drugs.

PATIENTS AND METHODS

We conducted a prospective study to evaluate the efficacy and safety of micafungin (MCFG), a novel antifungal agent of the echinocandin class, in an empirical therapy setting for patients with febrile neutropenia.

RESULTS

A total of 31 patients with acute leukemia who developed febrile neutropenia were enrolled in the study. Among them, 18 patients fulfilling the protocol-defined criteria, including 10 with persistent fever and 8 with recurrent fever, received MCFG empirically. Underlying diseases consisted of acute myeloid leukemia (n=15) and acute lymphoblastic leukemia (n=3). The median duration of neutropenia and drug administration was 22 and 9.5 days, respectively. Treatment success, defined as defervescence during the neutropenic period, absence of breakthrough fungal infections, and requiring no replacement of antifungal drugs, was achieved in 14 patients (78%). None of the patients required discontinuation or dose reduction due to adverse events except for one patient with severe hypokalemia.

CONCLUSIONS

Although the studied patients were limited in number, our results indicate that MCFG is an encouraging agent for empirical antifungal therapy in patients with febrile neutropenia, and deserves further investigation in large-scale studies.

Linear Pharmacokinetics of Micafungin and Its Active Metabolites in Japanese Pediatric Patients with Fungal Infections

The objective of this study was to propose the appropriate dosage regimen of micafungin for pediatric use, considering the effects of dose-linearity, age and other cofactors on the pharmacokinetics. Pharmacokinetic analysis of micafungin and its active metabolites (M1 and M2) after intravenous infusion at doses of 1 to 3 mg/kg was conducted for 19 Japanese pediatric patients (3 infants, 7 toddlers, and 9 pupils) with deep mycosis caused by either Aspergillus or Candida species. One patient was given the maximum dose of 6 mg/kg. The Cmax of micafungin increased in proportion to the dose. The mean values (S.D.) were 5.03 (2.33), 10.25 (4.45), 14.8 (5.52) and 21.1 microg/ml at 1, 2 , 3 and 6 mg/kg, respectively. These parameters were comparable to those seen in adults when the parameter was normalized by body weight. The elimination half life (t1/2) of micafungin over the dose range was apparently constant with the value of 13.1 h. There was no difference between the age groups observed. In fact, the metabolite concentrations were almost the same as those obtained for non-pediatric patients. Thus, micafungin showed the same dose-proportional pharmacokinetics in pediatric patients as it did in adults. No age dependent pharmacokinetics were observed in this study. It was concluded that the body weight adjustment was adequate for the treatment of micafungin in pediatric patients.

Efficacy of micafungin alone or in combination against experimental pulmonary aspergillosis

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.

Population Pharmacokinetic Analysis of Micafungin in Japanese Patients with Fungal Infections

The object of this analysis was to develop a population pharmacokinetic model of micafungin, a new anti-fungal agent of the echinocandin class, to optimize dosing in Japanese patients with fungal infections. Population pharmacokinetics parameters were determined using NONMEM based on pharmacokinetic data from 198 subjects in seven clinical studies, comprising four phase I, two phase II and one pediatric phase III study. The healthy subjects received intravenous infusion of 2.5-150 mg micafungin. Adult and pediatric patients, age range of 8 month to 15 yeras old, were received 25-150 mg and 1-6 mg/kg daily, respectively. A total of 1825 micafungin plasma samples were available for this analysis. Two-compartment pharmacokinetic model was adopted. The clearance of micafungin was influenced by body weight in children and platelet counts (PLT). However the PLT accounted for less than 20% of the variation of micafungin clearance in Japanese subjects. In conclusions, body weight is the primary covariate factor in pediatric patients. The dose adjustment by body weight would be required only pediatric patients for the micafungin therapy in Japanese patients with fungal infection.