Caspofungin versus liposomal amphotericin B for empirical antifungal therapy in patients with persistent fever and neutropenia

Approach to the complications of treatment for acute leukemia in the elderly

Acute leukemia is common in the elderly and, due to the aging population and poorer prognosis, represents a major challenge. Elderly acute leukemia patients have been arbitrarily defined as >or=55 to 65 years of age and are underrepresented in clinical trials. There are physiologic differences between elderly and non-elderly patients. A comprehensive understanding of these differences allows the development of a systematic approach to assessing the risks for treatment-related complications. Use of a comprehensive geriatric assessment (CGA), initially developed and validated in the general geriatric population, may allow more accurate assessment of the likelihood of chemotherapy-induced complications and allow for proactive risk minimization. Once complications to therapy develop, aggressive treatment is essential. Treatment related to common complications that arise from therapy will be reviewed. Further research directed at this population is required.

In vitro susceptibilities of Candida spp. to caspofungin: four years of global surveillance

Caspofungin is being used increasingly as therapy for invasive candidiasis. Prospective sentinel surveillance for emergence of in vitro resistance to caspofungin among invasive Candida spp. isolates is indicated. We determined the in vitro activity of caspofungin against 8,197 invasive (bloodstream or sterile-site) unique patient isolates of Candida collected from 91 medical centers worldwide from 1 January 2001 to 31 December 2004. We performed antifungal susceptibility testing according to the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) M27-A2 method and used a 24-h prominent inhibition endpoint for determination of the MIC. Of 8,197 invasive Candida spp. isolates, species distribution was as follows: 54% Candida albicans, 14% C. glabrata, 14% C. parapsilosis, 11% C. tropicalis, 3% C. krusei, and 4% other Candida spp. Overall, caspofungin was very active against Candida (MIC50/MIC90, 0.03/0.25 microg/ml; 98.2% were inhibited at a MIC of < or = 0.5 microg/ml and 99.7% were inhibited at a MIC of < or = 1 microg/ml). Results by species (expressed as MIC50/MIC90 and the percentage inhibited at < or = 1 microg/ml) were as follows: C. albicans, 0.03/0.06, 99.9; C. glabrata, 0.03/0.06, 99.9; C. parapsilosis, 0.5/0.5, 99.0; C. tropicalis, 0.03/0.06, 99.7; C. krusei, 0.12/0.5, 99.0; and C. guilliermondii, 0.5/1, 94.4. Of the 25 isolates with caspofungin MICs of >1 microg/ml, 12 isolates were C. parapsilosis, 6 isolates were C. guilliermondii, 2 isolates were C. rugosa, and 1 isolate each was C. albicans, C. glabrata, C. krusei, C. lusitaniae, and C. tropicalis. There was no significant change in caspofungin activity over the 4-year study period. Likewise, there was no difference in activity by geographic region. Caspofungin has excellent in vitro activity against invasive clinical isolates of Candida from centers worldwide. Our prospective sentinel surveillance reveals no evidence of emerging caspofungin resistance among invasive clinical isolates of Candida.

Infectious Disease Update: New Anti-Microbials

Effective antimicrobials are critical in controlling one of the most common conditions encountered in medicine, namely, skin and skin structure infections. Unfortunately, the identification of appropriate and novel antimicrobials is continually challenged by the emergence of antimicrobial resistance among bacteria, fungi, and parasites. This work will focus on describing novel antibacterials and antifungals approved by the United States Food and Drug Administration in the past 4 years.

Modern antifungal therapy for neutropenic fever

Empirical antifungal therapy has been shown to decrease the number of documented fungal infections in the setting of persistent fever during neutropenia. For decades, amphotericin B deoxycholate has been considered the agent of choice for first-line therapy in this setting. New antifungal agents associated with less toxicity, including the lipid formulations of amphotericin, voriconazole, and caspofungin, are now available and are considered to be suitable alternative first-line agents. In order to ensure appropriate therapy, however, the clinician must consider not only the differences between these antifungals but also patient-specific factors before initiating treatment.

A study to determine the safety profile and maximum tolerated dose of micafungin (FK463) in patients undergoing haematopoietic stem cell transplantation

This open-label, dose-escalation study assessed the maximum tolerated dose (MTD) of the new antifungal micafungin in patients undergoing haematopoietic stem cell transplantation (HSCT). Participants received 3, 4, 6 or 8 mg/kg/day micafungin intravenously from 7 days to a maximum of 28 days or until neutropaenia resolved. The MTD was defined as the highest dose not causing the same Grade 3 or 4 adverse event in three or more patients. All 36 participants received >/=8 days treatment for a median of 18 days (range: 8-28); 1 patient withdrew consent and a further 11 discontinued to receive another systemic antifungal agent for a suspected infection. No case of confirmed invasive fungal infection occurred. Adverse events were those expected for patients undergoing HSCT and showed no evidence of dose-related toxicity. Criteria for MTD were not met; no patient had a Grade 3 or 4 adverse event considered causally related to micafungin. Thus, the MTD of micafungin can be inferred to be 8 mg/kg/day or higher.

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.

Pharmacokinetics, safety, and efficacy of posaconazole in patients with persistent febrile neutropenia or refractory invasive fungal infection

The pharmacokinetic profiles, safety, and efficacies of different dosing schedules of posaconazole oral suspension in patients with possible, probable, and proven refractory invasive fungal infection (rIFI) or febrile neutropenia (FN) were evaluated in a multicenter, open-label, parallel-group study. Sixty-six patients with FN and 32 patients with rIFI were randomly assigned to one of three posaconazole regimens: 200 mg four times a day (q.i.d.) for nine doses, followed by 400 mg twice a day (b.i.d.); 400 mg q.i.d. for nine doses, followed by 600 mg b.i.d.; or 800 mg b.i.d. for five doses, followed by 800 mg once a day (q.d.). Therapy was continued for up to 6 months in patients with rIFI or until neutrophil recovery occurred in patients with FN. The 400-mg-b.i.d. dose provided the highest overall mean exposure, with 135% (P = 0.0004) and 182% (P < 0.0001) greater exposure than the 600-mg-b.i.d. and 800-mg-q.d. doses, respectively. However, exposure in allogeneic bone marrow transplant (BMT) recipients (n = 12) was 52% lower than in non-BMT patients. Treatment-related adverse events (occurring in 24% of patients) were mostly gastrointestinal in nature. Twenty-four percent of patients had adverse events leading to premature discontinuation (none were treatment related). In efficacy-evaluable patients, successful clinical response was observed in 43% with rIFI (56% of patients receiving 400 mg b.i.d., 17% receiving 600 mg b.i.d., and 50% receiving 800 mg q.d.) and 77% with FN (74% receiving 400 mg b.i.d., 78% receiving 600 mg b.i.d., and 81% receiving 800 mg q.d.). Posaconazole is well tolerated and absorbed. Divided doses of 800 mg (400 mg b.i.d.) provide the greatest posaconazole exposure.

Liposomal amphotericin B: clinical experience and perspectives

While amphotericin B deoxycholate (Fungizone, Apothecon Pharmaceuticals) has been considered by many to be the gold standard for the treatment for numerous invasive fungal infections for over 45 years, toxicities associated with its use often necessitate treatment modification or discontinuation. Lipid-based formulations, including liposomal amphotericin B (AmBisome, Fujisawa Healthcare, Inc.), were developed to decrease many of these toxicities while retaining broad antifungal spectrum and potency of amphotericin B. In clinical trials, liposomal amphotericin B has demonstrated efficacy comparable to that of amphotericin B deoxycholate while reducing the incidence of treatment-related nephrotoxicity, electrolyte-wasting, and infusion-related reactions. In addition, recent clinical trials have also compared liposomal amphotericin B with other antifungal classes. Acquisition costs of liposomal amphotericin B are substantially higher than those of amphotericin B deoxycholate and other antifungals. While pharmacoeconomic analyses consider outcomes and other treatment-related costs, they have yet to clearly demonstrate the cost-effectiveness of liposomal amphotericin B when compared with amphotericin B deoxycholate or other antifungal agents. This review will focus primarily on recent liposomal amphotericin B experience and attempt to put its use into perspective considering other available antifungal agents.

Impact of alternate definitions of fever resolution on the composite endpoint in clinical trials of empirical antifungal therapy for neutropenic patients with persistent fever: analysis of results from the Caspofungin Empirical Therapy Study

BACKGROUND

Sensitivity analyses were incorporated in a Phase III study of caspofungin vs. liposomal amphotericin B as empirical antifungal therapy for febrile neutropenic patients to determine the impact of varying definitions of fever resolution on response rates.

METHODS

The primary analysis used a 5-part composite endpoint: resolution of any baseline invasive fungal infection, no breakthrough invasive fungal infection, survival, no premature discontinuation of study drug, and fever resolution for 48 h during the period of neutropenia. Pre-specified analyses used 3 other definitions for fever resolution: afebrile for 24 h during the period of neutropenia, afebrile at 7 days post therapy, and eliminating fever resolution altogether from the composite endpoint. Patients were stratified on entry by use of antifungal prophylaxis and risk of infection. Allogeneic hematopoietic stem cell transplants or relapsed acute leukemia defined high-risk patients.

RESULTS

In the primary analysis, 41% of patients in each treatment group met the fever-resolution criteria. Low-risk patients had shorter durations of neutropenia but failed fever-resolution criteria more often than high-risk patients. In each exploratory analysis, response rates increased in both treatment groups compared to the primary analysis, particularly in low-risk patients.

CONCLUSIONS

Response rates for the primary composite endpoint for both treatment groups in this study were driven by low rates of fever resolution. Requiring fever resolution during neutropenia in a composite endpoint can mask more clinically relevant outcomes.

Assessment of nephrotoxicity of high-cumulative dose of liposomal amphotericin B in a pediatric patient who underwent allogeneic bone marrow transplantation

We describe a 9-yr-old boy who received the highest cumulative dose so far reported of liposomal amphotericin B. The patient underwent an allogeneic bone marrow transplantation (BMT) for adrenoleucodystrophy, after a conditioning regimen with busulfan, thiothepa and cyclophosphamide. Rabbit antithymoglobulin, cyclosporin and prednisone were used as prophylaxis against graft vs. host disease (GVHD). Post-transplant Epstein-Bar-virus-related lymphoma was diagnosed on day +68 and was treated with donor-derived lymphocytes. The patient developed a severe form of GVHD, and a progressive worsening of his neurological status because of progression of his underlying disease. Death from septic shock occurred 23 months after BMT. During prolonged hospitalization, 19,750 mg of liposomal amphotericin B, about 1000 mg/kg, were given for prophylactic or empirical therapeutic purposes without significant nephrotoxicity. This case suggests that liposomal amphotericin B is safe and well-tolerated even if is administered for long periods and a cumulative dose fivefold greater than the nephrotoxic threshold of amphotericin B deoxycholate is achieved.

Invasive fungal infections in neutropenic enterocolitis: a systematic analysis of pathogens, incidence, treatment and mortality in adult patients

Background

Neutropenic enterocolitis is a life-threatening complication most frequently occurring after intensive chemotherapy in acute leukaemias. Gramnegative bacteria constitute the most important group of causative pathogens. Fungi have also been reported, but their practical relevance remains unclear. The guidelines do not address concrete treatment recommendations for fungal neutropenic enterocolitis.

Methods

Here, we conducted a metaanalysis to answer the questions: What are frequency and mortality of fungal neutropenic enterocolitis? Do frequencies and microbiological distribution of causative fungi support empirical antimycotic therapy? Do reported results of antimycotic therapy in documented fungal neutropenic enterocolitis help with the selection of appropriate drugs? Following a systematic search, we extracted and summarised all detail data from the complete literature.

Results

Among 186 articles describing patients with neutropenic enterocolitis, we found 29 reports describing 53 patients with causative fungal pathogens. We found no randomised controlled trial, no good quality cohort study and no good quality case control study on the role of antifungal treatment. The pooled frequency of fungal neutropenic enterocolitis was 6.2% calculated from all 860 reported patients and 3.4% calculated from selected representative studies only. In 94% of the patients, Candida spp. were involved. The pooled mortality rate was 81.8%. Most authors did not report or perform antifungal therapy.

Conclusion

In patients with neutropenic enterocolitis, fungal pathogens play a relevant, but secondary role compared to bacteria. Evidence concerning therapy is very poor, but epidemiological data from this study may provide helpful clues to select empiric antifungal therapy in neutropenic enterocolitis.

Empiric antifungal therapy in neutropenic cancer patients

Hematopoietic stem cell transplant recipients and those patients with acute leukemia are at greatest risk for invasive fungal infections particularly due to Candida and Aspergillus species during periods of profound neutropenia. Empiric antifungal therapy in persistently febrile neutropenic patients has been adopted as a standard of care. Antifungal therapeutic options include: amphotericin B, lipid formulations of amphotericin B, fluconazole, itraconazole, voriconazole, and caspofungin. Amphotericin B preparations offer a beneficial effect for survival, defervescence, and a decrease in breakthrough fungal infections. Lipid formulations of amphotericin B may provide beneficial effects over amphotericin B with regard to survival, treatment of baseline fungal infection, breakthrough fungal infection, and fewer discontinuations due to lack of efficacy. Amphotericin B compounds produce a trend for better outcomes in defervescence, treatment of baseline fungal infections, prevention of breakthrough infections, and avoidance of discontinuation compared with the azoles. Caspofungin is also effective. The optimal empiric antifungal agent and the precise time of initiation remain to be determined.

Voriconazole versus amphotericin B in cancer patients with neutropenia

BACKGROUND

Opportunistic fungal infections are a major cause of morbidity and mortality in neutropenic cancer patients and antifungal therapy are used both empirically and therapeutically in these patients.

OBJECTIVES

To compare the benefits and harms of voriconazole with those of amphotericin B and fluconazole when used for prevention or treatment of invasive fungal infections in cancer patients with neutropenia.

SEARCH STRATEGY

MEDLINE and the Cochrane Library (May 2005). Letters, abstracts and unpublished trials were accepted. Contact to authors and industry.

SELECTION CRITERIA

Randomised trials comparing voriconazole with amphotericin B or fluconazole.

DATA COLLECTION AND ANALYSIS

Data on mortality, invasive fungal infection, colonisation, use of additional (escape) antifungal therapy and adverse effects leading to discontinuation of therapy were extracted by two authors independently.

MAIN RESULTS

Two trials were included. One trial compared voriconazole to liposomal amphotericin B as empirical treatment of fever of unknown origin (suspected fungal infections) in neutropenic cancer patients (849 patients, 58 deaths). The other trial compared voriconazole to amphotericin B deoxycholate in the treatment of confirmed and presumed invasive Aspergillus infections (391 patients, 98 deaths). In the first trial, voriconazole was significantly inferior to liposomal amphotericin B according to the authors' prespecified criteria. More patients died in the voriconazole group and a claimed significant reduction in the number of breakthrough fungal infections disappeared when patients arbitrarily excluded from analysis by the authors were included. In the second trial, the deoxycholate preparation of amphotericin B was used without any indication of the use of premedication and substitution with electrolytes and salt water to avoid handicapping this drug. This choice of comparator resulted in a marked difference in the duration of treatment on trial drugs (77 days with voriconazole versus 10 days with amphotericin B), and precludes meaningful comparisons of the benefits and harms of the two drugs.

AUTHORS' CONCLUSIONS

Liposomal amphotericin B is significantly more effective than voriconazole for empirical therapy of neutropenic cancer patients and should be preferred. For treatment of aspergillosis, there are no trials that have compared voriconazole with amphotericin B given under optimal conditions.

Treatment with caspofungin in immunocompromised paediatric patients: a multicentre survey

OBJECTIVES

Although a paediatric dosage has not been established, caspofungin is occasionally used in paediatric patients. We conducted a multicentre retrospective survey to obtain data on immunocompromised paediatric patients considered to require caspofungin therapy.

METHODS

The survey identified 64 patients (median age: 11.5 years; 25 females, 39 males) with haematological malignancies (48), marrow failure (9), solid tumours (3), haematological disorders (2) and congenital immunodeficiency (2) who received caspofungin for proven (17), probable (14) and possible (17) invasive fungal infections or empirically (16). Caspofungin was administered until intolerance or maximum efficacy at dosages individually determined by the responsible physician for refractory infection (38), intolerance of other agents (10) or as best therapeutic option (16).

RESULTS

The 64 patients received caspofungin for a median of 37 days (range 3-218) as single agent (20) or in combination (44). The median daily maintenance dosage was 1.07 mg/kg (95% CI 1.09-1.35; range 0.40-2.92) or 34.3 mg/m2 (95% CI 32.3-37.3; range 16.3-57.5). In none of the patients was therapy discontinued due to adverse events (AEs). Clinical AEs were mild to moderate and observed in 34 patients (53.1%). While mean glutamate pyruvate transaminase and glutamate oxalate transaminase values were slightly (P < 0.005) higher at the end of treatment (EOT), serum bilirubin, alkaline phosphatase and creatinine values were not different from baseline. Complete responses, partial responses or stabilization were observed in 5/7/3 of 17 patients with proven, in 3/4/3 of 14 patients with probable and in 7/6/1 of 15 evaluable patients with possible invasive infections. Thirteen of 16 patients on empirical therapy completed without breakthrough infection. Overall survival was 75% at the EOT and 70% at 3 months post-EOT, respectively.

CONCLUSIONS

Caspofungin displayed favourable safety and tolerance and may have useful antifungal efficacy in severely immunocompromised paediatric patients.

Caspofungin: a review of its use in the treatment of fungal infections

Caspofungin (Cancidas) is the first of a new class of antifungal agents, the echinocandins, that inhibit the synthesis of the fungal cell wall component beta-(1,3)-D-glucan. Caspofungin is administered once daily by slow intravenous infusion and is used to treat infections caused by Candida spp. and Aspergillus spp. Caspofungin is a valuable new antifungal agent with a novel mechanism of action. In comparative clinical trials, caspofungin was no less effective than liposomal amphotericin B in the empirical treatment of neutropenic patients with persistent fever, amphotericin B deoxycholate in the treatment of invasive candidiasis or fluconazole in the treatment of oesophageal candidiasis. Caspofungin also displayed broadly similar efficacy to amphotericin B deoxycholate in oesophageal or oropharyngeal candidiasis and was effective as salvage therapy in patients with invasive aspergillosis who were refractory to or intolerant of standard therapy. The tolerability profile of caspofungin was similar to that of fluconazole and superior to that of amphotericin B deoxycholate and liposomal amphotericin B. Therefore, in the appropriate indications, caspofungin is a viable alternative to amphotericin B deoxycholate, liposomal amphotericin B or fluconazole.

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

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

Pharmacokinetics, safety, and tolerability of caspofungin in children and adolescents

Caspofungin is a parenteral antifungal that inhibits beta-1,3-D-glucan synthesis. Although licensed for adult use, the appropriate caspofungin dosing regimen in pediatric patients is not yet known. We therefore investigated the pharmacokinetics and safety of caspofungin in pediatric patients. Thirty-nine children (ages 2 to 11 years) and adolescents (ages 12 to 17 years) with neutropenia were administered caspofungin using either a weight-based regimen (1 mg/kg of body weight/day) or a body surface area regimen (50 mg/m2/day or 70 mg/m2/day). Plasma samples for caspofungin profiles were collected on days 1 and 4. These results were compared to those from adults treated with either 50 or 70 mg/day for mucosal candidiasis. In children receiving 1 mg/kg/day (maximum, 50 mg/day), the area under the concentration-time curve over 24 h (AUC(0-24)) was significantly smaller (46% after multiple doses) than that observed in adults receiving 50 mg/day (P < 0.001). In children and adolescents receiving 50 mg/m2/day (maximum, 70 mg/day), the AUC(0-24) following multiple doses was similar to that for the exposure in adults receiving 50 mg/day. The AUC(0-24) and concentration trough (at 24 h) in pediatric patients receiving the 50-mg/m2 daily regimen were consistent across the range of ages. Caspofungin was generally well tolerated in this study. None of the patients developed a serious drug-related adverse event or were discontinued for toxicity. These results demonstrate that caspofungin at 1 mg/kg/day in pediatric patients is suboptimal. Caspofungin administration at 50 mg/m2/day provides a comparable exposure to that of adult patients treated with 50 mg/day.

Efficacy of caspofungin against invasiveCandida or invasiveAspergillus infections in neutropenic patients

BACKGROUND

Neutropenia is an indicator of poor prognosis in patients with fungal infections. All available clinical trial experience from the caspofungin development program was reviewed to ascertain the efficacy of caspofungin in neutropenic patients with documented invasive aspergillosis (IA) or invasive candidiasis (IC).

METHODS

The review was limited to neutropenic patients with proven IC or proven/probable IA at caspofungin onset. Data were available from four clinical trials. All patients had an absolute neutrophil count < 500/mm(3) at the initiation of caspofungin. In all cases caspofungin was administered as monotherapy at a dose of 50 mg/day, after a 70-mg loading dose. In all patients efficacy was assessed at the completion of caspofungin therapy. Success included complete and partial responses.

RESULTS

Sixty-eight neutropenic patients were identified with documented invasive infection, including 27 with IC and 41 with IA. Most patients had acute or chronic leukemia. A favorable response was noted in 63% (17 of 27 patients) of patients with IC, including a 58% (14 of 24 patients) response as first-line therapy and a 100% (3 of 3 patients) response as salvage therapy. Success in candidemia was 68% (17 of 25 patients). Outcomes across the different Candida species were similar. Favorable responses were noted in 39% (16 of 41 patients) of patients with IA, including a 42% (5 of 12 patients) response as first-line therapy and 38% (11 of 29 patients) response as salvage therapy. Success by site of IA was 40% for pulmonary (12 of 30 patients), 43% for sinus (3 of 7 patients), and 25% for skin/disseminated site (1 of 4 patients).

CONCLUSIONS

A review of the caspofungin database demonstrates that this echinocandin is effective in neutropenic patients with documented cases of IC or IA.

Consensus definitions for invasive fungal disease: Strengths, limitations, and revisions

The European Organization for Research and Treatment of Cancer (EORTC)/ Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (MSG) consensus definitions for opportunistic invasive fungal infections have achieved their objective in fostering better communication between researchers but their limitations necessitated revision. In the last two years a group of experts drawn from both sides of the Atlantic have agreed a proposal for a new set of definitions that attempt to rectify omissions and problems arising from the original set whilst preserving their basic principles.

Empirical antifungal therapy in patients with neutropenia and persistent or recurrent fever of unknown origin

Persistent or recurrent fever of unexplained origin (PFUO) in neutropenic patients receiving antibiotic therapy is commonly treated with empirical antifungal therapy (EAFT). EAFT was established as an adequate management of PFUO around 20 years ago with conventional amphotericin B deoxycholate (c-AmB), despite its high rate of infusional and systemic toxicities. In recent years, EAFT trials for PFUO have used less toxic agents, such as the lipid formulations of AmB, the new azoles, and the echinocandin, caspofungin. In clinical trials, the lipid formulations of AmB [especially liposomal AmB (L-AmB)] provided similar efficacy with lower toxicity but at a much higher cost. Although rarely used in clinical practice, fluconazole is equivalent to c-AmB, provided patients at high risk of Aspergillus infections are excluded. Intravenous itraconazole was shown to be equivalent to c-AmB, with a lower toxicity. Voriconazole did not meet non-inferiority criteria when compared with L-AmB. Caspofungin was shown to be non-inferior to L-AmB and more effective in treating baseline invasive fungal infections. To date, alternatives to AmB have shown less toxicity, but improved efficacy is less clear. This is probably because of the weakness of the indication and to the consequent difficulty in establishing objective and reproducible endpoints for comparisons. The new challenge for physicians in this field is probably presumptive antifungal therapy, an approach based on patient risk-group stratification for developing invasive candidiasis or aspergillosis and/or the use of new diagnostic techniques to identify patients at a very early stage of infection.

Defining clinical failure for salvage studies

In patients with invasive aspergillosis (IA), there are numerous clinical settings where stable disease or progression of findings or deterioration of the patient's condition does not indicate failure, and subsequent response to a 'salvage' antifungal is not necessarily attributable to this drug. Many patients, in whom pulmonary aspergillosis emerges during profound neutropenia, show enlargement of their lesions on computer tomography (CT) scans, eventually accompanied by clinical deterioration, during hematopoietic recovery. This may in fact represent the recruitment of neutrophils and monocytes to the pulmonary 'battlefield', resulting in a favorable clinical outcome also without changing antifungal treatment. Infarcted tissue may contain vital filamentous fungi, because it is poorly penetrated by the antifungal, not indicating a lack of efficacy of this drug against the respective fungal pathogen. In patients treated with an echinocandin, serum galactomannan levels may increase despite successful treatment. Piperacillin-tazobactam or other semi-synthetic beta-lactam antibiotics may cause false positive serum Aspergillus galactomannan levels. Patients primarily treated with a lipid formulation of AmB (LF-AmB), who are switched to a 'salvage' antifungal, will unequivocally receive a combination therapy due to the persistence of high LF-AmB concentrations in tissue. Criteria to define 'clinical refractoriness', 'resistance', 'non-response' or 'failure' respectively should be re-defined. One option to establish a more valid definition would be to use a composite score including clinical as well as radiological and microbiological or mycological criteria. The latter may include non-culture based methods such as serum galactomannan. Assessment should not be made earlier than after seven days of full-dose systemic antifungal treatment. However, in individual cases, e.g. a patient with hematopoietic recovery, who shows an increasing volume of pulmonary aspergillosis and clinical deterioration, it may be recommended to refrain from switching the patient to another regimen and continue the current antifungal treatment for another seven days before failure is stated. Clinical studies on second-line antifungal treatment for IA should be randomized and blinded, patients should be evaluated separately with respect to their reason for 'failure' of primary antifungal treatment, and stratified according to their previous antifungal treatment. Ideally, the first-line regimen would be standardized. Host criteria such as neutropenia or graft-versus-host disease (GVHD) should be clearly defined and documented with respect to their course over time, and patients should be stratified according to these criteria. A three-arm study (continuation of primary antifungal vs. combination of primary antifungal with a 'salvage' drug vs. the 'salvage' drug alone) would be ideal.

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.

La caspofungine : du mécanisme d'action aux applications thérapeutiques

SUBJECT

Since the last two decades, the incidence of invasive fungal infections has drastically increased. It becomes urgent to enlarge the panel of antifungal drugs with more potent activity and less toxicity. Since the target of all previously available antifungal agents is the synthesis of ergosterol located in the fungal membrane, the fungicidal activity of echinocandins is based on the inhibition of the glucan synthesis. Caspofungin (CAS) (Cancidas MSD France), a cyclic hexapeptide semisynthetic derivative of pneumocandin B, is the first available drug belonging to this new class.

MAIN ISSUES

CAS has a fungicidal activity covering a wide range of pathogens, including Candida spp. Data from animal and human studies demonstrate that the drug is 96% plasmatic protein bound and the proposed route of elimination is hepatic. For the treatment of systemic, oesophageal and oropharyngeal candidiasis, CAS has the same efficacy as amphotericin B or as triazoles. Among 50% of patients suffering of invasive aspergillosis with intolerance or resistance to classical treatments, CAS induces a successful response and even more in combination with these drugs. For patients with fever and neutropenia, the efficacy of CAS is non inferior than Ambisome. CAS is generally well tolerated. The most common adverse effects are fever, nausea, vomiting and complication at the infusion point of the vein. CAS has a better tolerability than amphotericin B and a similar one compared to fluconazole (FCZ) but with less drug interactions.

PERSPECTIVES

For rare but severe localisations (i.e.: endocarditis, cerebral, arthritis, etc.), CAS combinations with classical antifungal drugs could be tested in order to improve the life time in patients suffering from systemic fungal infections.

The prevention of infection post-transplant: the role of prophylaxis, preemptive and empiric therapy

The close linkage of infection with the nature and intensity of the transplant immunosuppressive program has led to the concept of the therapeutic prescription. This has two components: an immunosuppressive one to prevent or treat rejection and graft-versus-host disease and an antimicrobial one to make it safe. This review provides a conceptual framework to approach the risk and risk periods for infection in solid organ and hematopoietic stem cell transplant recipients as well as an approach to antimicrobial use in this population.

Pharmacoeconomics of antifungal pharmacotherapy – challenges and future directions

The frequency and severity of invasive fungal infections have been increasingly recognised and new antifungal therapies have expanded the therapeutic armamentarium available to manage such infections. Antifungal agents comprise a significant portion of antibiotic expenditures at major medical centres, prompting adoption of cost-containment measures and treatment guidelines. This paper reviews available data regarding the costs associated with managing fungal infections, including pharmacoeconomic analyses that have been performed in the setting of documented fungal infections, as well as prophylactic and empiric use of antifungal agents. The challenges of performing such studies are discussed, as well as the limitations of published investigations. Finally, recommendations are made regarding the design and implementation of future pharmacoeconomic analyses that can help establish the true costs of managing invasive fungal infections in at-risk patient populations.

Breakthrough Candida krusei fungemia during fluconazole prophylaxis followed by breakthrough zygomycosis during caspofungin therapy in a patient with severe aplastic anemia who underwent stem cell transplantation

We report a case of breakthrough invasive zygomycosis in a stem cell transplant recipient who was receiving caspofungin for treatment of a breakthrough Candida krusei fungemia that occurred during fluconazole prophylaxis. Also, patients receiving the echinocandin caspofungin remain at risk for pathogens, such as zygomycetes, that are intrinsically resistant to this agent.

Caspofungin treatment in severely ill, immunocompromised patients: a case-documentation study of 118 patients

BACKGROUND

Caspofungin has shown efficacy in empirical antifungal therapy in neutropenic patients, refractory invasive Aspergillus infections and invasive candidiasis. Here we report the currently largest series of patients treated with caspofungin outside clinical trials.

METHODS

Centres in Germany that were known to treat patients with invasive fungal infections were asked to fill out detailed questionnaires for all patients treated with caspofungin. No effort was made to influence the decision to use caspofungin.

RESULTS

A total of 118 patients were evaluable (median age 48 years, interquartile range 38-58), out of which 41 (35%) suffered from acute leukaemia, 31 (26%) had allogeneic stem cell transplants, 16 (14%) lymphoma or myeloma, 8 (7%) autologous stem cell transplants and 22 (19%) other causes for immunosuppression. One hundred and six patients were evaluable for efficacy out of which 68 (64%) patients achieved a complete or partial remission. A total of 81 out of 115 (70%) patients were alive 30 days after the end of caspofungin therapy. Response rates were similar in proven (20/32, 63%) and probable (27/46, 59%) infections, in neutropenic patients (41/55, 75%) and in patients who were (44/70, 63%) or were not (24/36, 67%) refractory to antifungal pre-treatment. The response rate in mechanically ventilated patients was 29% (7/24). Caspofungin was well tolerated, even in 14 patients, who were concomitantly treated with ciclosporin A, no drug-related elevations of bilirubin, alanine aminotransferase or creatinine were found.

CONCLUSIONS

This open case study of severely ill patients with invasive fungal infections demonstrates both excellent efficacy and very low toxicity of caspofungin.

Caspofungin susceptibility testing of isolates from patients with esophageal candidiasis or invasive candidiasis: relationship of MIC to treatment outcome

The caspofungin clinical trial database offers an opportunity to assess susceptibility results for Candida pathogens obtained from patients with candidiasis and allows for correlations between efficacy outcomes and MICs. Candida isolates have been identified from patients enrolled in four studies of esophageal candidiasis and two studies of invasive candidiasis. The MICs of caspofungin for all baseline isolates were measured at a central laboratory using NCCLS criteria (document M-27A); MICs for caspofungin were defined as the lowest concentration inhibiting prominent growth at 24 h. MICs were then compared to clinical and microbiological outcomes across the two diseases. Susceptibility testing for caspofungin was performed on 515 unique baseline isolates of Candida spp. obtained from patients with esophageal candidiasis. MICs for caspofungin ranged from 0.008 to 4 microg/ml; the MIC50 and MIC90 were 0.5 and 1.0 microg/ml, respectively. Susceptibility testing was also performed on 231 unique baseline isolates of Candida spp. from patients with invasive candidiasis. The majority (approximately 96%) of MICs were between 0.125 and 2 microg/ml, with MIC50 and MIC90 for caspofungin being 0.5 and 2.0 microg/ml, respectively. Overall, caspofungin demonstrated potent in vitro activity against clinical isolates of Candida species. A relationship between MIC for caspofungin and treatment outcome was not seen for patients with either esophageal candidiasis or invasive candidiasis. Patients with isolates for which the MICs were highest (>2 microg/ml) had better outcomes than patients with isolates for which the MICs were lower (<1 microg/ml). Additionally, no correlation between MIC and outcome was identified for specific Candida species.

Safety, diagnostic yield, and therapeutic implications of flexible bronchoscopy in patients with febrile neutropenia and pulmonary infiltrates

OBJECTIVE

To evaluate the safety, diagnostic yield, and therapeutic implications of flexible bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsy in patients with febrile neutropenia and pulmonary infiltrates.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of all patients with neutropenic fever and pulmonary infiltrates evaluated by flexible bronchoscopy and BAL between January and December 2002 at the Mayo Clinic in Rochester, Minn. Appropriate demographic, clinical, microbiological, and histological data and procedure-related complications were summarized. Therapeutic decisions implemented based on Information obtained by bronchoscopy, and 28-day mortality were determined.

RESULTS

Thirty-five patients with febrile neutropenia and associated pulmonary infiltrates were identified. Flexible bronchoscopy, including 35 BALs and 9 transbronchial biopsies, was performed safely (3 complications). The diagnostic yield of BAL was 49%. Sputum analysis was underused (only 34%) but complementary to BAL. The combined diagnostic yield of BAL and sputum analysis was 63%. Transbronchial biopsy provided additional information to BAL and sputum analysis In only 1 patient and did not substantially increase the combined diagnostic yield. The most common diagnoses identified were fungal pneumonias (15/35 [43%]) and diffuse alveolar hemorrhage (5/35 [14%]). Bronchoscopic findings resulted in management changes in 51% of patients. The 28-day mortality rate was 26% and was highest in patients who required mechanical ventilatory assistance before bronchoscopy.

CONCLUSION

The favorable safety record, good diagnostic yield, and frequent therapeutic implications support the routine use of BAL for the evaluation of pulmonary inflitrates in neutropenic patients. Bronchoalveolar lavage should be combined with the analysis of several sputum specimens. Transbronchial biopsy did only change the management of 1 patient.

Mediastinal Mass Due to Aspergillus fumigatus After Lung Transplantation: A Case Report

We report a rare case of mediastinal mass caused by Aspergillus fumigatus in a lung transplant recipient. The patient presented 9 months after bilateral lung transplantation for cystic fibrosis with intermittent fevers and new onset atrial fibrillation/flutter caused by a 7-cm mediastinal mass invading the left atrium. The mass was resected, and a prolonged course of voriconazole and caspofungin was given, which resulted in a complete clinical response. Despite long-term suppressive therapy with voriconazole, a relapse occurred 16 months after the initial diagnosis. This case highlights the challenges in the prevention and treatment of invasive aspergillosis in lung transplant recipients.

Suitability of Caspofungin for Aerosol Delivery

BACKGROUND

Aerosolized antifungal therapy is a promising route of drug delivery for pulmonary aspergillosis due to attainment of high localized concentrations. Caspofungin, a new antifungal agent with proven efficacy against invasive aspergillosis, has ideal potential for aerosolization.

STUDY OBJECTIVE

To examine in vitro the suitability of caspofungin for aerosol administration by characterizing factors that influence efficacy and airway tolerance of aerosol delivery: physicochemical properties, aerodynamics of drug particles, and efficiency of nebulizing systems.

DESIGN

Physicochemical characteristics of caspofungin solutions (10 mg/mL and 30 mg/mL) were analyzed: osmolality, pH, viscosity, and surface tension. A time-of-flight aerosol spectrometer API Aerosizer was used to determine aerosol particle size and distribution. Drug output was quantified by high-performance liquid chromatography assay. Nebulizer efficiency was measured by drug output and respirable fraction (percentage of aerosolized particles with a 1 to 5 mum aerodynamic diameter) and compared among three jet nebulizer/compressor systems: device 1, Micromist (Hudson RCI; Temecula, CA)/Pulmo-Aide (model 5650D; DeVilbiss; Somerset, PA); device 2, Sidestream MS 2400/Envoy model IRC 1192 (Invacare; Elyria, OH); and device 3, Pari LC Star/Proneb Ultra (Pari Respiratory Equipment; Midlothian, VA).

MEASUREMENTS AND RESULTS

Caspofungin requires 0.9% NaCl rather than sterile water as the diluent and addition of 0.3N NaOH buffer to adjust acidity of solutions (pH 6.17 to 6.26) in order to achieve optimal physicochemical properties for airway tolerability (osmolality, 150 to 550 milliosmol per kilogram; chloride ion, 31 to 300 mmol/L; and pH 7.4). The drug output rate increased with higher concentrations of drug solution: device 1, 4.0 mg/min vs 12.5 mg/min; device 2, 5.4 mg/min vs 14.7 mg/min; and device 3, 2.3 mg/min vs 12 mg/min, respectively. The percentage of particles within the respirable range varies depending on device and concentration of drug solutions (10 mg/mL vs 30 mg/mL): device 1, 85% vs 38%; device 2, 44% vs 57%; and device 3, 83% vs 93%, respectively.

CONCLUSION

Caspofungin solution with adjustments appears to have physicochemical and aerodynamic characteristics suitable for aerosolization when used with either the Pari LC Star/Proneb Ultra or Micromist/Pulmo-Aide devices. Further in vivo testing is warranted.

Tratamiento antifúngico empírico en pacientes seleccionados con fiebre persistente y neutropenia

Empirical antifungal treatment (EAT) in neutropenia is mainly aimed at improving the poor prognosis of patients with invasive fungal infection through early treatment. The Infectious Diseases Society of America recommends initiating EAT in patients with persistent fever after 5-7 days of antibacterial treatment, and in those in whom remission of neutropenia is not imminent. Nevertheless, EAT has not been shown to be more effective than a placebo, it does not show better results than directed antifungal treatment, its effectiveness is minimal, it is not innocuous, and it is not very efficient with the use of most antifungal agents. All considered, we believe that the aforementioned recommendation for EAT treatment is unjustified. In its place we propose the application of EAT in patients selected on the basis of clinical criteria and risk factors.

Cryptococcal fungemia in a neutropenic patient with AIDS while receiving caspofungin

Empiric choice of anti-fungal therapy in febrile neutropenia should be based upon a host's susceptibility to specific fungal pathogens. We present a case of a patient with multiple risk factors for fungemia including HIV infection, Hodgkin's disease, corticosteroid use and chemotherapy-induced neutropenia who developed disseminated cryptococcal infection while receiving caspofungin.

Galactomannan and computed tomography-based preemptive antifungal therapy in neutropenic patients at high risk for invasive fungal infection: a prospective feasibility study

BACKGROUND

Empirical antifungal therapy is the standard treatment for persistent or relapsing antibiotic-resistant neutropenic fever. However, overtreatment resulting in increased toxicity and treatment-related cost is a major shortcoming of such therapy. We assessed the feasibility of a "preemptive" approach based on the incorporation of sensitive, noninvasive diagnostic tests for consecutive high-risk neutropenic patients who had received fluconazole prophylaxis while avoiding empirical therapy.

METHODS

A total of 136 treatment episodes for persons who were at risk of acquiring invasive fungal infection (IFI) were screened for the presence of galactomannan with an enzyme immunoassay. A diagnostic evaluation, which included thoracic computed tomography scanning (HRCT) and bronchoscopy with lavage, was performed on the basis of well-defined clinical, radiological, and microbiological criteria. Only seropositive patients and patients with a positive microbiological test result plus supportive radiological findings received liposomal amphotericin B.

RESULTS

Neutropenic fever developed in 117 episodes, of which at least 41 episodes (35%) satisfied existing criteria for empirical antifungal therapy. However, our protocol-driven preemptive approach reduced the rate of antifungal use for these episodes from 35% to 7.7% (a 78% reduction) and led to the early initiation of antifungal therapy in 10 episodes (7.3%) that were clinically not suspected of being IFI. No undetected cases of invasive aspergillosis were identified; 1 case of zygomycosis was missed. Breakthrough candidemia was diagnosed by conventional culture techniques and was treated successfully. With use of a preemptive approach, the 12-week survival rate for patients with IFI was 63.6% (it was 63.1% for those with invasive aspergillosis).

CONCLUSION

Preemptive therapy based on enzyme immunoassay and HRCT reduced the exposure to expensive and potentially toxic drugs and offered effective antifungal control, but it failed to detect non-Aspergillus IFI.

Pharmacological properties and clinical efficacy of a recently licensed systemic antifungal, caspofungin

Caspofungin, a semisynthetic derivative of the pneumocandin B(0), is the first licensed compound of a new class of antifungal agents, the echinocandins. It attacks the fungal cell by selective inhibition of the beta-(1,3)-d-glucan synthase, which is not present in mammalian cells. In vitro studies have indicated a potent fungicidal effect on Candida species, and in vivo studies in immunocompromised animals with invasive candidiasis demonstrated a favourable outcome. In randomized clinical trials in patients with oropharyngeal/oesophageal and invasive candidiasis, caspofungin was at least as effective as amphotericin B deoxycholate, yet showed a significantly superior safety profile. Of patients with invasive aspergillosis refractory to or intolerant of other antifungal agents, 45% showed a partial or complete response to caspofungin given as a salvage treatment. Also, it demonstrated comparable clinical efficacy but superior tolerability in the empirical antifungal therapy in neutropenic patients compared with liposomal amphothericin B. Caspofungin has an excellent tolerability and a low potential for drug interactions. Thus, caspofungin represents an interesting and clinically valuable new antifungal drug that broadens the available therapeutic armamentarium for the treatment of invasive fungal infections.

Specific substitutions in the echinocandin target Fks1p account for reduced susceptibility of rare laboratory and clinical Candida sp. isolates

An association between reduced susceptibility to echinocandins and changes in the 1,3-beta-d-glucan synthase (GS) subunit Fks1p was investigated. Specific mutations in fks1 genes from Saccharomyces cerevisiae and Candida albicans mutants are described that are necessary and sufficient for reduced susceptibility to the echinocandin drug caspofungin. One group of amino acid changes in ScFks1p, ScFks2p, and CaFks1p defines a conserved region (Phe 641 to Asp 648 of CaFks1p) in the Fks1 family of proteins. The relationship between several of these fks1 mutations and the phenotype of reduced caspofungin susceptibility was confirmed using site-directed mutagenesis or integrative transformation. Glucan synthase activity from these mutants was less susceptible to caspofungin inhibition, and heterozygous and homozygous Cafks1 C. albicans mutants could be distinguished based on the shape of inhibition curves. The C. albicans mutants were less susceptible to caspofungin than wild-type strains in a murine model of disseminated candidiasis. Five Candida isolates with reduced susceptibility to caspofungin were recovered from three patients enrolled in a clinical trial. Four C. albicans strains showed amino acid changes at Ser 645 of CaFks1p, while a single Candida krusei isolate had a deduced R1361G substitution. The clinical C. albicans mutants were less susceptible to caspofungin in the disseminated candidiasis model, and GS inhibition profiles and DNA sequence analyses were consistent with a homozygous fks1 mutation. Our results indicate that substitutions in the Fks1p subunit of GS are sufficient to confer reduced susceptibility to echinocandins in S. cerevisiae and the pathogens C. albicans and C. krusei.

Safety of Caspofungin for Treating Invasive Nasal Sinus Aspergillosis in a Kidney Transplant Recipient

INTRODUCTION

Invasive fungal sinusitis is a rare but often fatal infection in immunocompromised patients. Aggressive antifungal treatment is mandatory, but is not without risk. Caspofungin, an antifungal agent that is a member of the echinocandin family, an inhibitor of glucan synthesis in the fungal wall, is active against Aspergillus and Candidae infections. Although it works on the fungal wall, it does not affect mammalian cells; hence, its toxicity is minimal.

CASE SUMMARY

This report describes a case of invasive Aspergillus sinusitis in a kidney transplant recipient with diabetes mellitus. The infection involved the apex of the right orbit causing optic nerve compression. The patient was treated with transnasal endoscopic decompression of the optic nerve and intravenous AmBisome (liposomal amphotericin B) for 2 weeks without clinical improvement. The combination of caspofungin and AmBisome administered for another 2 weeks yielded partial improvement. The AmBisome had to be discontinued due to deterioration of renal and hepatic function, but the patient completed a further 7-week course of caspofungin alone. Retro-orbital biopsy confirmed a complete response to treatment; the patient's renal and hepatic function returned to normal.

CONCLUSION

This case indicates that caspofungin is effective to treat invasive Aspergillus sinusitis in kidney transplant recipients. This agent is well tolerated and safe with respect to renal and hepatic function.