Liposomal amphotericin B for empirical therapy in patients with persistent fever and neutropenia. National Institute of Allergy and Infectious Diseases Mycoses Study Group

Bad bugs need drugs: an update on the development pipeline from the Antimicrobial Availability Task Force of the Infectious Diseases Society of America

The Antimicrobial Availability Task Force (AATF) of the Infectious Diseases Society of America (IDSA) has viewed with concern the decreasing investment by major pharmaceutical companies in antimicrobial research and development. Although smaller companies are stepping forward to address this gap, their success is uncertain. The IDSA proposed legislative and other federal solutions to this emerging public health problem in its July 2004 policy report "Bad Bugs, No Drugs: As Antibiotic R&D Stagnates, a Public Health Crisis Brews." At this time, the legislative response cannot be predicted. To emphasize further the urgency of the problem for the benefit of legislators and policy makers and to capture the ongoing frustration our clinician colleagues experience in their frequent return to an inadequate medicine cabinet, the AATF has prepared this review to highlight pathogens that are frequently resistant to licensed antimicrobials and for which few, if any, potentially effective drugs are identifiable in the late-stage development pipeline.

Antimicrobial therapy for patients with severe sepsis and septic shock: an evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for antimicrobial therapy for patients with severe sepsis and septic shock that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Since the prompt institution of therapy that is active against the causative pathogen is one of the most important predictors of outcome, clinicians must establish a system for rapid administration of a rationally chosen drug or combination of drugs when sepsis or septic shock is suspected. The expanding number of antibacterial, antifungal, and antiviral agents available provides opportunities for effective empiric and specific therapy. However, to minimize the promotion of antimicrobial resistance and cost and to maximize efficacy, detailed knowledge of the likely pathogens and the properties of the available drugs is necessary for the intensivist.

Sepsis associated with immunosuppressive medications: an evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for sepsis associated with immunosuppressive medications that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Immunosuppressed patients, by definition, are susceptible to a wider spectrum of infectious agents than immunologically normal patients and, thus, require a broader spectrum antimicrobial regimen when they present with sepsis or septic shock. Special expertise managing immunosuppressed patient populations is needed to predict and establish the correct diagnosis and to choose appropriate empiric and specific agents and maximize the likelihood that patients will survive these microbial challenges.

Long-term antifungal prophylaxis in high-risk hematopoietic stem cell transplant recipients

The risks for invasive fungal infections, particularly mould infections such as invasive aspergillosis, among hematopoietic stem cell transplant (HSCT) recipients are linked to the duration and severity of myelosuppression and immunosuppression. Strategies to prevent invasive fungal infections have focused primarily on the use of orally administered azole antifungal agents during the neutropenic period rather than on the more prolonged post-engraftment period. The major limitations of these studies included the heterogeneity among the subjects studied for fungal infection risk factors, the agents administered, the dosing, and duration of prophylaxis. More recent studies have attempted to examine the efficacy of antifungal prophylaxis strategies among allogeneic HSCT recipients to day 100 and beyond. It is clear that a variety of products have efficacy in preventing invasive candidiasis, including imidazole and triazole antifungals, low-dose amphotericin B, and the echinocandin, micafungin; however, only the extended spectrum azole, itraconazole, has been shown to impact the incidence of proven invasive aspergillosis. Other extended spectrum azole antifungal agents, voriconazole and posaconazole, are being studied as long-term prophylaxis in high-risk HSCT recipients. While clinical trials have suggested that a duration of prophylaxis against moulds of six months or more may be required, it remains unclear if this is required in all cases. The prophylactic efficacy over time may be linked to the degree of immunosuppression as measured by markers such as the numbers of circulating CD4 T lymphocytes. Concerns about selection for resistant moulds among long-term recipients of these drugs are emerging. The cumulative experience to date suggests that long-term antifungal chemoprophylaxis is feasible and effective when applied in defined circumstances. The concerns about treatment-related toxicities, resistance, and costs are valid.

Pulmonary fungal infection with yeasts and pneumocystis in patients with hematological malignancy

Invasive fungal infections are an important cause of morbidity and mortality in patients with hematological malignancies, and in particular fungal pneumonia is the main clinical manifestation in this category of patients. The fungal agents responsible for this complication are various, but Aspergillus spp. and other molds such as Zygomycetes or Fusarium spp. represent the most frequently isolated micro-organisms. Less commonly, pneumonia could be due to other 'no-molds' fungal agents such as Candida spp, Cryptococcus spp, or Pneumocystis jirovecii . This review mainly focuses on practical aspects relevant to epidemiology, diagnosis and therapeutic management of the rare cases of pneumonia due to no-molds agents in patients affected by hematological malignancies.

Aspergillosis in the CLEAR outcomes trial: working toward a real-world clinical perspective

Aspergillosis is a potentially lethal infection of immunocompromised patients. Until 10 years ago, antifungal therapy was largely limited to amphotericin B deoxycholate. Perceived poor response rates and inherent toxicities with amphotericin B deoxycholate were a major stimulus for the development of newer antifungals, including lipid-formulated amphotericin B, broad spectrum azoles, and echinocandins. Response rates to antifungals are highly dependent on the underlying diagnosis and degree of immune suppression of the patient. Patients at highest risk of death from aspergillosis also have very high mortality rates from other causes as well. Outcomes reported in historical literature reviews fail to distinguish between overall mortality and death attributable to aspergillosis. While this distinction can often be difficult to assess clinically, the net effect is to underestimate the therapeutic success rates of antifungals. The CLEAR (Collaborative Exchange of Antifungal Research) project started as a post approval survey to monitor clinical use of amphotericin B lipid complex (ABLC). The scope of the CLEAR project included collection of clinical data to assess outcomes in patients with invasive fungal infections treated with ABLC. Clinical data from more than 3500 patients were entered into the CLEAR database. Outcomes were assessed for 509 patients with documented aspergillosis and complete data records. Overall response rate was 63% (cured/improved/stable) with site-specific response rates of 61%, 59%, and 32% for lung, sinus, and central nervous system infections, respectively. Solid organ transplant recipients had higher response rates than patients with hematological malignancies. Bone marrow transplant recipients had the lowest response rates. Clinical response rates with ABLC reported in the CLEAR trial are higher than response rates reported for amphotericin B deoxycholate in other trials. Since it is unlikely we will see any new comparative Phase III trials for aspergillosis, CLEAR-type outcome studies will prove useful for the foreseeable future to guide clinical management of aspergillosis.

Chronic disseminated candidiasis in patients with acute leukemia: emphasis on diagnostic definition and treatment

BACKGROUND

Chronic disseminated candidiasis (CDC) is a form of invasive fungal infection that occurs most commonly in patients with acute leukemia treated with chemotherapy. Recent studies have provided evidence for diagnostic alternatives to invasive procedures and more therapeutic options for the management of this complication. In order to put diagnostic criteria and methodological approach to the disease into the perspective of developing strategies for therapy, all relevant studies published in the English literature over the last 30 years were examined.

MATERIALS AND METHODS

The English-language articles located through MEDLINE (1966 to present) and from selected bibliographies.

RESULTS

There is increased recognition of CDC as complication of treatment with chemotherapy in patients with acute leukemia. Liver biopsy may not always be revealing or feasible to perform in some patients. Among the imaging modalities, magnetic resonance imaging has obtained preeminence as a non-invasive tool for the diagnosis of hepatosplenic fungal infections. Administration of amphotericin B (Amp B) in relatively large cumulative doses is needed to ensure appropriate control of the infection and prevention of future relapse. Patients intolerant of, or refractory to conventional Amp B have been successfully salvaged using fluconazole or lipid formulations of Amp B. A constellation of clinical, laboratory and radiologic parameters should be used to determine response and efficacy of therapy. There is sufficient evidence to support the safety and feasibility of continuing chemotherapy for acute leukemia in conjunction with antifungal treatment in patients diagnosed with CDC.

CONCLUSION

The development of CDC in patients with acute leukemia does not preclude further chemotherapy or constitute contraindication for bone marrow transplantation. Knowledge of the course and pattern of evolution of the disease and adopting aggressive therapeutic approach will likely reduce the morbidity and mortality from this complication.

Recent developments in the management of invasive fungal infections in patients with hematological malignancies

Despite recent advances in the last decade, invasive fungal infections are still associated with a high morbidity and mortality. Invasive fungal infections constitute severe infectious complications in patients with hematological malignancies receiving myelosuppressive chemotherapy or sustained immunosuppression after allogeneic transplant regimens. Following a long period of stagnation, considerable progress has been made during the last 5 years in non-culture-based diagnostics and in the treatment of invasive fungal infections. This review highlights recent developments in the epidemiology, diagnosis, and treatment in the context of state-of-the-art management of invasive fungal infections in cancer patients.

Drug-Induced Renal Failure in the ICU

Drug-induced renal failure is a frequent complication in the setting of ICU. Generally spoken pathomechanisms leading to drug-induced renal failure can be divided into hemodynamic effects, epithelial toxicity or crystalline nephropathy. The risk of drug-induced renal failure is increased by any form of hypovolemia (i.e. true hypovolemia or reduced effective circulating volume), older age, pre-existent renal impairment, and concomitant application of two or more nephrotoxins. This article reviews drugs most frequently responsible for renal failure in the ICU and discusses preventive measures. (Int J Artif Organs 2004; 27: 1034-42)

Alternative dosing regimens of liposomal amphotericin B (AmBisome) effective in treating murine systemic candidiasis

OBJECTIVES

This study was done to determine whether high dose AmBisome (4-20 mg/kg), given intermittently, could reduce the frequency of dosing needed to treat murine systemic candidiasis when compared with conventional daily treatment.

METHODS

Mice were immunosuppressed with cyclophosphamide every 3 days, beginning day -3 before challenge with log(10) 5.0 cfu Candida albicans. Treatment was begun 48-72 h post-challenge with daily or intermittent dose regimens of AmBisome, followed by determination of kidney cfu for up to 1 month post-treatment.

RESULTS

A single AmBisome dose of 4 mg/kg was as effective as four daily, 1 mg/kg treatments. A total of 8 mg/kg, given as 4 mg/kg on days 2 and 4, or as 5 mg/kg on day 2 followed by 1 mg/kg on days 3, 4, and 5, also produced comparable efficacy. While 20 mg/kg given day 2, 4 and 6 post-challenge as a 1 week loading dose, followed by one 10 mg/kg treatment on day 13, decreased the fungal burden by up to 5 logs compared with controls (log(10) 2.3 cfu/g and log(10) 7.5 cfu/g, respectively), 20 mg/kg given Monday, Wednesday and Friday for 5 weeks, reduced the fungal burden to undetectable levels (i.e. log(10) 1.0 cfu).

CONCLUSIONS

Significant reduction or clearance of kidney cfu, following intermittent, high dose AmBisome treatment, indicated that non-daily dosing regimens could be successfully used instead of conventional daily dosing to treat established C. albicans infection in immunosuppressed mice.

Lipid-based amphotericin in pulmonary zygomycosis: safety and efficacy of high exposure in a renal allograft recipient

Zygomycosis is associated with a high mortality in immunosuppressed patients. Treatment typically includes surgical resection and administration of intravenous amphotericin B. Success of treatment may require withdrawal of immunosuppression, with risk of graft loss. We report the successful treatment of invasive pulmonary zygomycosis, following initial surgical resection, using very high doses of lipid-based amphotericin B without withdrawal of immunosuppression. The patient received daily doses up to 10 mg/kg/day (51 g cumulatively) of lipid-based amphotericin B along with a brief course of intrapleural amphotericin. Despite immunosuppression not being withdrawn, the patient's kidney allograft function remained stable. We conclude that high doses of lipid-based amphotericin B can be safe and effective as part of the treatment regimen for pulmonary zygomycosis.

Influence of amphotericin B deoxycholate or amphotericin B colloidal dispersion on renal tubule epithelium in rat

Amphotericin B deoxycholate (AmB) or Amphotericin B colloidal dispersion (ABCD) are used in clinics for the treatment of systemic fungal infections. The goal of our study was to compare the nephrotoxicity of these drugs in rat kidney. The effects of AmB and ABCD on the ultrastructure of the epithelium of renal tubules were studied and evaluated using morphometric and statistical methods. Two groups of 3 animals were established: group 1 was treated with AmB desoxycholate and group 2, to which ABCD was applied. AmB caused more than ABCD ultrastructural changes in the cytoplasm of the epithelial cells: damage to mitochondria, vacuolation of cytoplasm, and increased values of volume density of peroxisomes. However, we failed to observe significant differences in morphology and density of the other cell organelles. The proximal tubules seemed to be more sensitive to the nephrotoxic influence of both formulas than the distal tubules of rat kidney. Although, AmB causes more severe damage than ABCD, both drugs cause damage to renal tubuli.

Efficacy and safety of caspofungin for treatment of invasive aspergillosis in patients refractory to or intolerant of conventional antifungal therapy

BACKGROUND

Invasive aspergillosis (IA) is an important cause of morbidity and mortality among immunocompromised patients. Echinocandins are novel antifungal molecules with in vitro and in vivo activity against Aspergillus species.

METHODS

We investigated the efficacy and safety of caspofungin in the treatment of IA. Ninety patients with IA who were refractory to or intolerant of amphotericin B, lipid formulations of amphotericin B, or triazoles were enrolled to receive caspofungin.

RESULTS

Efficacy was assessed for 83 patients who had infection consistent with definitions of IA and who received >or=1 dose of study drug. Common underlying conditions included hematologic malignancy (48% of patients), allogeneic blood and marrow transplantation (25% of patients), and solid-organ transplantation (11% of patients). Seventy-one patients (86%) were refractory to and 12 patients (14%) were intolerant of previous therapy. A favorable response to caspofungin therapy was observed in 37 (45%) of 83 patients, including 32 (50%) of 64 with pulmonary aspergillosis and 3 (23%) of 13 with disseminated aspergillosis. Two patients discontinued caspofungin therapy because of drug-related adverse events. Drug-related nephrotoxicity and hepatotoxicity occurred infrequently.

CONCLUSION

Caspofungin demonstrated usefulness in the salvage treatment of IA.

Intérêt d’Abelcet® dans la prise en charge des enfants neutropéniques fébriles

AIM OF STUDY

In order to optimise the use of new forms of Amphotericine B (Ampho B), a decisional tree was created at the end of 2001 in the paediatric hemato-oncology unit for the empirical antifungal treatment in febrile neutropenic children: the standard remained conventional Ampho B and Abelcet was proposed in case of antecedent or occurrence of a deterioration of the renal function (DRF). In order to validate the place of Abelcet we initiated a retrospective study over year 2002.

RESULTS

21 treatments were begun in 14 children for a median duration of 8 days (1-48 days). Three kind of indications were found: DRF antecedent (10 episodes: A group), DRF occurrence during a treatment with conventional Ampho B (7 episodes: B group), age lower than 1 year (3 episodes). 81% of the children were thus treated according to the decisional tree. The clinical tolerance was good in 90% of the cases, with a premedication in half of the cases. The study of the renal function showed a good renal tolerance for 6 episodes out of 9 evaluable in A group, 3 resolutions and 2 stabilisation of the renal failure for the 5 evaluable episodes of the B group. Seven to ten days of treatment by Abelcet were necessary to obtain the renal failure resolved.

CONCLUSION

This study confirms the interest of Abelcet in the empirical antifungal treatment in febrile neutropenic children and specially in children having antecedents of DRF related or not to a treatment with conventional Ampho B.

Combating infections in hematopoietic stem cell transplant recipients

Infections with a diverse group of microorganisms remain the leading causes of morbidity and mortality after hematopoietic stem cell transplantation. Importantly, the epidemiology of infectious complications has shifted substantially with changes in antimicrobial prophylaxis, conditioning regimens and graft manipulation, such that invasive mould infections and late viral infections are now the over-riding concerns. New antivirals and antifungals have entered clinical practice and hold considerable promise for improved outcomes.

Design of Efficacy Trials of Cytokines in Combination with Antifungal Drugs

Resolution of invasive fungal infections is often dependent on recovery from an immunocompromised state, which indicates that host defense mechanisms are extremely important in the clearance of fungal pathogens. Immunotherapy aimed at enhancement of host defense mechanisms may improve clinical outcome of invasive mycoses. The design of trials of immunotherapy against fungal pathogens requires profound knowledge of the host defense mechanisms that are involved in invasive fungal infections. Prospective phase II studies with recombinant granulocyte colony-stimulating factor and interferon-gamma have been done. Recombinant interferon-gamma is a candidate for phase III trials of adjunctive immunotherapy for cryptococcal meningitis, invasive aspergillosis, and candidemia, but the proper design of future trials will be crucial to establish whether immunotherapy is of clinical value in the treatment of invasive fungal infections.

A new era of antifungal therapy

Invasive fungal infections pose major management problems for clinicians caring for hematopoietic cell transplant patients. Two major fungal genera, Candida and Aspergillus, account for most fungal infections. Rates of systemic Candida infection range from 15% to 25%, mostly in the pre-engraftment period. Prophylaxis by fluconazole has dramatically reduced the frequency of early Candida infections. Caspofungin has recently been shown to offer an excellent alternative to amphotericin B (with less toxicity) or fluconazole (with a broader spectrum) for therapy of systemic Candida infections. Aspergillus infections occur in 15% to 20% of allogeneic hematopoietic cell transplant patients, most frequently in the post-engraftment period; they are associated with a severe diminution of cell-mediated immune responses by graft-versus-host disease and prolonged corticosteroid use. Voriconazole, a recently introduced broad-spectrum azole, has excellent activity against Aspergillus and is generally well tolerated. Voriconazole currently offers the best prospect for success and tolerance as a first-line treatment for aspergillosis. Second-line therapies include lipid formulations of amphotericin B, caspofungin, or intravenous itraconazole. Unfortunately, early initiation of therapy for aspergillosis is frequently not possible because of inaccurate diagnostics. One new diagnostic, the galactomannan assay, has recently been approved, and others are in development; these offer promise for earlier diagnosis without the need for invasive procedures. It is hoped that these new therapies and new diagnostics will usher in a new era of antifungal therapy.

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

BACKGROUND

Patients with persistent fever and neutropenia often receive empirical therapy with conventional or liposomal amphotericin B for the prevention and early treatment of invasive fungal infections. Caspofungin, a member of the new echinocandin class of compounds, may be an effective alternative that is better tolerated than amphotericin B.

METHODS

In this randomized, double-blind, multinational trial, we assessed the efficacy and safety of caspofungin as compared with liposomal amphotericin B as empirical antifungal therapy. At study entry, patients were stratified according to risk and according to whether they had previously received antifungal prophylaxis. A successful outcome was defined as the fulfillment of all components of a five-part composite end point.

RESULTS

Efficacy was evaluated in 1095 patients (556 receiving caspofungin and 539 receiving liposomal amphotericin B). After adjustment for strata, the overall success rates were 33.9 percent for caspofungin and 33.7 percent for liposomal amphotericin B (95.2 percent confidence interval for the difference, -5.6 to 6.0 percent), fulfilling statistical criteria for the noninferiority of caspofungin. Among patients with baseline fungal infections, a higher proportion of those treated with caspofungin had a successful outcome (51.9 percent vs. 25.9 percent, P=0.04). The proportion of patients who survived at least seven days after therapy was greater in the caspofungin group (92.6 percent vs. 89.2 percent, P=0.05). Premature study discontinuation occurred less often in the caspofungin group than in the amphotericin B group (10.3 percent vs. 14.5 percent, P=0.03). The rates of breakthrough fungal infections and resolution of fever during neutropenia were similar in the two groups. Fewer patients who received caspofungin sustained a nephrotoxic effect (2.6 percent vs. 11.5 percent, P<0.001), an infusion-related event (35.1 percent vs. 51.6 percent, P<0.001), or a drug-related adverse event or discontinued therapy because of drug-related adverse events.

CONCLUSIONS

Caspofungin is as effective as and generally better tolerated than liposomal amphotericin B when given as empirical antifungal therapy in patients with persistent fever and neutropenia.

Emerging fungal resistance

There has been an increase in systemic fungal infections over the past several decades, partially because of an increasing number of critically ill patients, surgical procedures, and immunosuppressive therapies, as well as the use of more invasive diagnostic and therapeutic medical procedures. Concomitant with this increase in infections has been the increase in azole-resistant Candida species and opportunistic molds with intrinsic resistance to many of the currently available antifungal agents. This review focuses on antifungal resistance, with emphasis on emerging resistance patterns and emerging fungi that are intrinsically resistant to antifungal agents.

Emerging fungal diseases: the importance of the host

More yeasts and molds are now recognized to cause more human disease than ever before. This development is not due to a change in the virulence of these fungi, but rather to changes in the human host. These changes include immunosuppression secondary to the pandemic of HIV, the use of life-saving advances in chemotherapy and organ transplantation, and the use of corticosteroids and other immunosuppressive agents to treat a variety of diseases. Fungi that were once considered common saprophytes are now recognized as potential pathogens in these patients. This situation necessitates better communication than ever between the clinician, pathologist, and clinical mycologist to ensure the prompt and accurate determination of the cause of fungal diseases.

Continuous and 4 h infusion of amphotericin B: a comparative study involving high-risk haematology patients

OBJECTIVES

To assess whether a continuous infusion of amphotericin B (CI-AmB) is less nephrotoxic than a 4 h infusion in haematology patients with fever and neutropenia, including bone-marrow transplant recipients. Efficacy was assessed as a secondary end-point.

PATIENTS AND METHODS

We conducted a retrospective cohort study over a 2 year period. A total of 1073 haematology admissions were reviewed (98.3% complete) and 81 admissions were eligible for study entry; 39 received CI-AmB and 42 a 4 h infusion of AmB.

RESULTS

Renal impairment occurred significantly less frequently with CI-AmB compared with a 4 h infusion of AmB [10% versus 45%, respectively, odds ratio (OR) 0.14; 95% confidence interval (CI) 0.04-0.5, P < 0.001]. The difference was maintained among allogeneic transplant recipients (P = 0.007) and patients receiving concurrent nephrotoxic drugs (P < 0.001). An AmB infusion rate of <0.08 mg/kg/h was associated with a significant reduction in renal impairment (P < 0.001). A difference in survival was observed between the continuous and 4 h infusion of AmB (95% versus 79%, respectively, OR 5.1; 95% CI 1.02-25.1, P = 0.03).

CONCLUSIONS

CI-AmB appears to be significantly less nephrotoxic than 4 h infusion AmB in haematology patients with fever and neutropenia--including high-risk bone-marrow transplant recipients--without increasing mortality. An AmB infusion rate of <0.08 mg/kg/h appears to be a safe threshold, associated with reduced renal impairment.

Update on antifungal treatment of invasive Candida and Aspergillus infections. Derzeitiger Kenntnisstand in der antimykotischen Behandlung invasiver Candida- und Aspergillus-Infektionen

Invasive Candida and Aspergillus infections are among the most common serious complications occurring in chronically immunosuppressed patients, in particular those with hematological malignancies and transplant recipients. A rational, early systemic antifungal treatment can be based upon imaging diagnostic techniques as well as upon conventional mycological and non-culture-based procedures. The availability of well tolerable and highly efficacious systemic antifungals has improved the spectrum of therapeutic options and the success rates of antifungal treatment. However, with respect to high treatment costs associated with these new agents, it is mandatory to specify indications and limitations for the use of these substances. Voriconazole may well become the new standard primary treatment of invasive aspergillosis. The role of the new echinocandins such as caspofungin, which has recently been approved for salvage treatment of resistant and refractory Aspergillus infections, in primary or combination treatment of invasive aspergillosis must be further studied. Caspofungin is at least as effective as, yet significantly better tolerated than amphotericin B for primary treatment of invasive candidosis in non-neutropenic patients, and has been approved for this indication. The selection of systemic antifungals in patients with invasive Candida infection critically depends upon the identification of Candida species involved, because some non-albicans Candida spp. are resistant to azole antifungals.

Empirical Antifungal Therapy in Treating Febrile Neutropenic Patients

Persistent or recurrent unexplained fever in neutropenic patients receiving antibiotics can be caused by invasive fungal infections, which are often difficult to diagnose. Early trials of empirical antifungal therapy with amphotericin B deoxycholate (AmB) documented reductions in the frequency of and the morbidity and mortality associated with invasive fungal infections. Because of AmB's infusional and renal toxicities, subsequent trials used newer, less toxic agents, such as the lipid formulations of AmB, the extended-spectrum azoles, and, more recently, the echinocandins. To date, alternatives to AmB have shown less toxicity, but improved efficacy has been less clear. Overall, empirical antifungal therapy can help prevent the morbidity associated with many fungal infections, eliminate concerns about diagnostic pitfalls, and prevent breakthrough undetected infections. However, its potential shortcomings are overtreatment, toxicity, and increased treatment-related costs when treatment is given to persons not needing it. Newer diagnostic tools are needed to target those most in need of antifungal therapy.

Amphotericin B nephrotoxicity in children

Amphotericin B is the treatment of choice for severe systemic fungal infections. Nephrotoxicity is the most clinically significant adverse effect, but studies examining nephrotoxicity in children are scarce. Nephrotoxicity includes decreased glomerular filtration rate and distal tubulopathy with urinary loss of potassium and magnesium, renal tubular acidosis, loss of urine concentrating ability, and sometimes Fanconi's syndrome. The mechanisms involved in nephrotoxicity include the use of deoxycholate, the vehicle for amphotericin, reduction in renal blood flow and glomerular filtration rate, increased salt concentrations at the macula densa, interaction of amphotericin with ergosterol in the cell membrane, and apoptosis in proximal tubular cells and medullary interstitial cells. Some risk factors for amphotericin nephrotoxicity have been determined over the years. Cumulative dosage, treatment duration, and dosing schedule as well as the combination of amphotericin with other nephrotoxic drugs, such as diuretics and cyclosporine, are important risk factors. Mechanisms to prevent nephrotoxicity include the use of lipid formulations such as amphotericin B lipid complex, amphotericin B colloidal dispersion, and liposomal amphotericin B and the concurrent use of volume repletion. Amiloride can be considered in serious potassium loss.

Effects of fluid and electrolyte management on amphotericin B-induced nephrotoxicity among extremely low birth weight infants

OBJECTIVE

Greater use of invasive procedures and aggressive antimicrobial therapy predispose extremely low birth weight (ELBW) infants to systemic fungal sepsis. Despite its adverse effects (including renal and electrolyte disturbances), amphotericin B (amphoB) remains the preferred drug for fungal therapy. Multiple studies have indicated that sodium loading may prevent renal toxicity among animals and human adults. The effects of fluid and electrolyte management on amphoB-induced nephrotoxicity among ELBW infants have not been evaluated extensively. The purpose of this study was to examine the effects of fluid and electrolyte management on amphoB-induced nephrotoxicity among ELBW infants.

DESIGN/METHODS

The medical records were reviewed for all ELBW infants (birth weights of < or =1250 g) who developed systemic fungal sepsis, requiring amphoB therapy, between January 1992 and December 2000. Demographic, clinical, and laboratory data were collected from the medical records for each patient.

RESULTS

Fungal sepsis requiring amphoB treatment developed for 4.4% of ELBW infants (25 of 573 infants), with a gestational age of 25 +/- 1 weeks and a birth weight of 738 +/- 37 g, at a postnatal age of 16 +/- 2 days. Renal compromise, as manifested by low urine output and high creatinine levels, occurred for 44% of those infants (11 of 25 infants). There was no difference between the infants who developed renal compromise (renal compromise group [RCG], n = 11) and those who did not (no-renal-compromise group [NCG], n = 14) with respect to birth weight, gestational age, and risk factors predisposing the infants to fungal sepsis. The RCG demonstrated a decrease in urine output by 3.4 +/- 2 days and an increase in serum creatinine levels by 3.9 +/- 2 days after the initiation of amphoB therapy. Infants in the RCG had a significantly higher incidence of hyponatremia, compared with infants in the NCG (7 of 11 infants vs 0 of 14 infants), with no significant difference in the incidences of hypokalemia (2 of 11 infants vs 0 of 14 infants). Infants in the RCG, compared with infants in the NCG, had significantly lower mean daily sodium intakes in the 4 days before the initiation of amphoB therapy (2.6-2.9 mEq/kg per day vs 4.2-4.7 mEq/kg per day) and in the first 4 days of amphoB treatment (2.7-3.1 mEq/kg per day vs 4.5-5.6 mEq/kg per day). Mean daily sodium intakes were not statistically significantly different between the 2 groups between day 5 and day 10 of amphoB therapy. Infants in the RCG tended to have lower mean daily potassium intakes in the 4 days before the initiation of amphoB therapy and during the first 4 days of amphoB therapy. Subsequently, the mean daily potassium intakes remained not statistically significantly different between the groups. Mean daily fluid intakes were not different between the groups.

CONCLUSIONS

Conventional amphoB combined with adequate hydration and higher sodium intakes of >4 mEq/kg per day may provide effective protection against amphoB-induced nephrotoxicity among ELBW infants. Our data confirm the published results of animal and human adult studies and suggest that higher sodium intakes may prevent renal compromise during amphoB therapy among ELBW infants.

[New antifungal agents and bronchopulmonary mycoses]

The frequency of respiratory mycosal infections has increased over recent Years. Diagnosis has been improved by recent epidemiological data and advances in radiological and mycological diagnostic methods. Two new antifungal agents have recently received marketing approval: voriconazole and caspofungine. Voriconazole belongs to the echinocandin family of antifungals. Sites of action of antifungals have become more diversified: amphotericins act on ergosterol directly, azolated agents act on the synthesis of ergosterol, flucytosine affects synthesis of nucleic acids, and echinocandins alter the fungal wall. Synergetic or additive combinations, such as amphotericin-caspofungine, or voriconazole-caspofungine, can be proposed for advanced disease. Thus both first intention and secondary treatments, particularly for systemic candidiasis and aspergillosis, have been modified. These new protocols take into consideration the severity of the mycosal infection, co-morbidity, and drug combinations as well as cost.

Safety and efficacy of caspofungin and liposomal amphotericin B, followed by voriconazole in young patients affected by refractory invasive mycosis

OBJECTIVE

Data on the use of combination of liposomal amphotericin B and caspofungin followed by voriconazole, as maintenance or further rescue treatment, in 10 patients with invasive mycosis are reported.

MATERIAL AND METHODS

The diagnoses were acute leukemia (7), myelodysplastic syndrome (1) and Hodgkin's lymphoma (1). All patients developed an invasive mycosis (proven, 3; probable, 6; and possible, 1) refractory to first-line antifungal treatment (liposomal amphotericin B in all patients except one who received fluconazole).

RESULTS

Rescue therapy with a combination of caspofungin and liposomal amphotericin B was well tolerated, hypokalemia, and thrombophlebitis being the most common side-effects. Combination therapy was administered for a median of 17 d, range 6-40. Among the nine patients with proven or probable mycosis, one was not evaluated because of early death caused by massive hemoptysis whilst in the remaining eight patients, the response was classified as complete, stable and failure in four, three, and one patients, respectively. Complete response was also observed in patient with possible mycosis. Eight of nine patients received voriconazole for a median of 75 d, range 42-194. Voriconazole was well tolerated although some drug interactions were observed during treatment with methotrexate and digoxin. After a median follow-up of 125 d, nine of 10 patients are alive. Overall, a favorable response to antifungal treatment (including the case of possible mycosis) was obtained in eight of 10 patients.

CONCLUSION

These data suggest that medical antifungal treatment may be intensified in severely ill patients without significantly compromising patient safety. The combination of synergistic antifungal drugs as well as their sequential use warrants further investigation by a larger randomized controlled study.

Localised invasive sino-orbital aspergillosis: characteristic features

BACKGROUND/AIM

To describe the characteristic constellation of historical, clinical, radiographic, and histopathological findings of localised invasive sino-orbital aspergillosis based on the authors' recent experience of four consecutive cases presenting over a 6 month period. Treatment and outcome are reviewed.

METHODS

A case series of four patients with review of the English language literature.

RESULTS

There have been 17 reported cases of invasive sino-orbital aspergillosis in healthy individuals over the past 33 years. The authors report four patients who presented during a 6 month period with persistent and significant pain followed by progressive ophthalmic signs-clinical histories reflecting the literature. Similar imaging findings were also noted: focal hypodense areas within apical infiltrates on contrasted computed tomography correspond to abscesses seen at surgery, and sinus obliteration or involvement of the adjacent sinus lining was noted on magnetic resonance imaging. Bone erosion (often focal) was also seen. There is frequently a delay in making the correct diagnosis, and often disease progression occurs despite treatment.

CONCLUSIONS

The authors encountered four cases of invasive sino-orbital aspergillosis, three of which occurred in otherwise healthy individuals. The clinician must be aware of the characteristic presentation so that earlier diagnosis, management, and improved outcomes can be achieved.

Low-dose amphotericin B lipid complex vs. conventional amphotericin B for empirical antifungal therapy of neutropenic fever in patients with hematologic malignancies--a randomized, controlled trial

BACKGROUND

Conventional amphotericin B (c-AmB) remains the empirical antifungal treatment of choice for neutropenic patients with persistent fever of unknown origin (FUO). Unfortunately, empirical treatment with c-AmB is hampered by its safety profile, with frequent infusion-related adverse events (IRAEs) and renal toxicity. Amphotericin B lipid complex (ABLC) has been investigated for this indication due to its low toxicity profile. The recommended dose of ABLC is 5 mg/kg/d, which is five to seven times higher than the recommended dose of c-AmB.

METHODS

This randomized, controlled trial includes 105 adult patients with hematologic malignancies and with FUO after receiving chemotherapy or autologous stem cell transplantation. Patients were randomly allocated to receive ABLC at 1 mg/kg/d or c-AmB at 0.6 mg/kg/d for empirical antifungal therapy.

RESULTS

The incidence of renal toxicity was significantly lower in the ABLC group, compared with c-AmB group: 8% vs. 32%, respectively (P = 0.003). The rates of IRAEs were similar in both groups (73% for ABLC vs. 77% for c-AmB). The overall response rate was 72% for ABLC compared with 48% for c-AmB (P = 0.018). This difference was mainly due to the significantly higher renal toxicity in the c-AmB group. The number of emergent fungal infections and overall mortality were similar in both groups.

CONCLUSIONS

This randomized trial suggests that ABLC at 1 mg/kg/d produces less nephrotoxicity than c-AmB, without differences in the incidence of IRAEs and with similar efficacy.

Empirical antifungal therapy

The number of fungal infections is increasing, particularly in patients with cancer, and represent a major problem given the relatively poor response rates, especially for aspergillosis, and the high cost. Empirical therapy has become an accepted practice as delay in instituting therapy is clearly associated with increased morbidity and mortality. In terms of efficacy for the management of persistent febrile neutropenic patients, there is no convincing evidence that conventional amphotericin B (ampho B) is inferior to any other agent; the lipid formulations of ampho B provide similar efficacy with lower toxicity but at a much higher cost. Fluconazole is equivalent to ampho B, provided patients at high risk of aspergillus infections are excluded. Itraconazole and voriconazole, as empirical therapies, are equivalent to conventional ampho B and liposomal ampho B, respectively; toxicity is definitely lower and voriconazole is more effective at preventing breakthrough fungal infections.

Guidelines for the use of antifungal agents in the treatment of invasiveCandidaand mould infections

ABSTRACT Treatment of invasive fungal infections is increasingly complex. Amphotericin B deoxycholate has long been the mainstay of treatment. However, there has been increasing recognition of both the propensity for nephro-toxicity in haematology, transplant and intensive care patients as well as its adverse impact on morbidity and mortality. This has coincided with the availabilty of newer, and in certain settings, more effective antifungal agents. Although the newer agents clearly cause less nephrotoxicity than amphotericin B, drug interactions, hepatic effects and unique side-effects need to be considered. The spectrum of the newer triazoles and echinocandins varies, highlighting the importance of accurate identification of the causative organism where possible. Consensus Australian guidelines have been developed to assist clinicians with treatment choices by reviewing the current evidence for the efficacy, the toxicity and the cost of these agents.

Management of infectious complications in the hematopoietic stem cell transplant recipient

Despite impressive accomplishments in supportive care over the past decade, infections with a diverse group of microorganisms remain leading causes of morbidity and mortality after hematopoietic stem cell transplantation. The epidemiology of infectious complications has shifted substantially in the past decade with changes in antimicrobial prophylaxis, conditioning regimens, and graft manipulation, such that invasive mould infections and late viral infections are now the overriding concerns. Individual patient risk for infections is predicated on multiple disease-specific, patient-specific, and transplant-related factors but often tracks with the cumulative level of immunosuppression (such as dose of corticosteroids used for the treatment of graft vs host disease [GVHD]). New antivirals and antifungals have entered clinical practice and hold considerable promise for improved outcomes.

New and emerging antifungal agents: impact on respiratory infections

Fungal pathogens are increasingly important causes of respiratory disease, yet the number of antifungal agents available for clinical use is limited. Use of amphotericin B deoxycholate is hampered by severe toxicity. Triazole agents currently available have significant drug interactions; fluconazole has a limited spectrum of activity and itraconazole was, until recently, available only in oral formulations with limited bioavailability. The development of resistance to all three agents is increasingly being recognized and some filamentous fungi are resistant to the action of all of these agents. In the past few years, new antifungal agents and new formulations of existing agents have become available.The use of liposomal amphotericin B preparations is associated with reduced, but still substantial, rates of nephrotoxicity and infusion-related reactions. An intravenous formulation of itraconazole has been introduced, and several new triazole agents have been developed, with the view of identifying agents that have enhanced potency, broader spectra of action and improved pharmacodynamic properties. One of these, voriconazole, has completed large-scale clinical trials. In addition, caspofungin, the first of a new class of agents, the echinocandins, which inhibit cell wall glucan synthesis, was approved for use in the US in 2001 as salvage therapy for invasive aspergillosis. It is hoped that the availability of these agents will have a significant impact on the morbidity and mortality of fungal respiratory infections. However, at the present time, our ability to assess their impact is limited by the problematic nature of conducting trials for antifungal therapy.

Acute toxic renal failure

Acute renal failure (ARF) is a common problem in intensive care medicine. Even modest degrees of ARF not requiring dialysis treatment increase the risk of death approximately fivefold. Despite the widespread appreciation of the role of nephrotoxic drugs in their contribution to ARF, these drugs continue to have an ongoing aetiological role. Potentially nephrotoxic drugs include non-steroidal anti-inflammatory drugs, radiocontrast agents, antimicrobial and anaesthetic agents. Endogenous compounds such as myoglobin and haemoglobin may furthermore cause toxic nephropathy. Tubular injury initiated by toxins often results from a combination of acute renal vasoconstriction and direct cellular toxicity due to intracellular accumulation of the toxin, or, alternatively, may be mediated immunologically in case of interstitial nephritis. Patients with reduced renal functional reserve, cardiovascular co-morbidity, diabetes mellitus, and advanced age are at increased risk. Awareness of the range of toxins on the one hand and simple measures such as adequate pre-hydration of the patient and drug monitoring on the other hand may be sufficient to avoid drug-induced ARF or minimize its clinical severity in susceptible patients.

Lipid formulations of amphotericin B preserve and stabilize renal function in HSCT recipients

The current study assessed renal function based on medical records in adult hematopoietic stem cell transplant (HSCT) recipients with proven or probable invasive fungal infection (IFI) transplanted between 1995 and 2000. We confirm that amphotericin B deoxycholate (AmB-d) is nephrotoxic in a large percentage of HSCT recipients. Due to nephrotoxicity, defined as serum creatinine (SCr) >2.5 mg/dl or a 100% increase in SCr from baseline, 88% of patients treated with AmB-d were switched to a lipid formulation of amphotericin B (LFAB). In total, 53% of patients initiated on AmB-d were switched within the first week of therapy. Significantly more patients (70.6%) treated with AmB-d experienced a 100% increase in SCr from baseline compared to patients treated with either AmBisome (44.4%) or Abelcet (41.2%). A Cox Proportional Hazards Model revealed that, compared to patients initiated on AmBisome or Abelcet, the risk of nephrotoxicity (RR=1.5 vs AmBisome; RR=1.7 vs Abelcet), dialysis (RR=2.4 vs AmBisome; RR=1.4 vs Abelcet), and death (RR=2.0 vs AmBisome; RR=1.1 vs Abelcet) were all increased for patients initiated on AmB-d. Study results suggest that renal function improves and mortality declines when an LFAB is given to HSCT patients as initial therapy rather than as second-line therapy, the current practice.

Comparative drug disposition, urinary pharmacokinetics, and renal effects of multilamellar liposomal nystatin and amphotericin B deoxycholate in rabbits

The comparative drug dispositions, urinary pharmacokinetics, and effects on renal function of multilamellar liposomal nystatin (LNYS; Nyotran) and amphotericin B deoxycholate (DAMB; Fungizone) were studied in rabbits. Drug concentrations were determined by high-performance liquid chromatography as total concentrations of LNYS and DAMB. In comparison to a standard dose of 1 mg of DAMB/kg of body weight, therapeutic dosages of LNYS, i.e., 2, 4, and 6 mg/kg, resulted in escalating maximum concentrations (Cmax) (17 to 56 microg/ml for LNYS versus 3.36 microg/ml for DAMB; P<0.001) and values for the area under the concentration-time curve from 0 to 24 h (AUC(0-24)) (17 to 77 microg.h/ml for LNYS versus 12 microg.h/ml for DAMB; P<0.001) in plasma but a significantly faster total clearance from plasma (0.117 to 0.080 liter/h/kg for LNYS versus 0.055 liter/h/kg for DAMB; P=0.013) and a < or =8-fold-smaller volume of distribution at steady state (P=0.002). Urinary drug concentration data revealed a > or =10-fold-higher Cmax (16 to 10 microg/ml for LNYS versus 0.96 microg/ml for DAMB; P=0.015) and a 4- to 7-fold-greater AUC(0-24) (63 to 35 microg.h/ml for LNYS versus 8.9 microg.h/ml for DAMB; P=0.015) following the administration of LNYS, with a dose-dependent decrease in the dose-normalized AUC(0-24) in urine (P=0.001) and a trend toward a dose-dependent decrease in renal clearance. Except for the kidneys, the mean concentrations of LNYS in liver, spleen, and lung 24 h after dosing were severalfold lower than those after administration of DAMB (P, <0.002 to <0.001). Less than 1% each of the total dose of LNYS was recovered from the kidneys, liver, spleen, and lungs; in contrast, a quarter of the total dose was recovered from the livers of DAMB-treated animals. LNYS had dose-dependent effects on glomerular filtration and distal, but not proximal, renal tubular function which did not exceed those of DAMB at the highest investigated dosage of 6 mg/kg. The results of this experimental study demonstrate fundamental differences in the dispositions of LNYS and DAMB. Based on its enhanced urinary exposure, LNYS may offer a therapeutic advantage in systemic fungal infections involving the upper and lower urinary tracts that require therapy with antifungal polyenes.

Infections due to emerging and uncommon medically important fungal pathogens

The emergence of less common but medically important fungal pathogens contributes to the rate of morbidity and mortality, especially in the increasingly expanding population of immunocompromised patients. These pathogens include septate filamentous fungi (e.g., Fusarium spp., Scedosporium spp., Trichoderma spp.), nonseptate Zygomycetes, the endemic dimorphic pathogen Penicillium marneffei, and non-Cryptococcus, non-Candida pathogenic yeast (e.g., Trichosporon spp.). The medical community is thus called upon to acquire an understanding of the microbiology, epidemiology and pathogenesis of these previously uncommon pathogens in order to become familiar with the options for prevention and treatment.

Metaanálisis de la seguridad y eficacia de la anfotericina B liposómica en el tratamiento empírico de la neutropenia febril

BACKGROUND AND OBJECTIVE

We compared the safety and efficacy of liposomal amphotericin B with other formulations of amphotericin B and voriconazol as an empirical treatment of febrile neutropenia.

MATERIAL AND METHOD

Several randomized controlled clinical trials, designed to evaluate the safety and/or efficacy of liposomal amphotericin B in the empirical treatment of febrile neutropenia, in comparison with other amphotericin B formulations or voriconazol, were identified by means of a search in MEDLINE, EMBASE and Cochrane Controlled Trials Register's data bases. American Society of Microbiology and American Society of Clinical Oncology abstracts, presented between 1999 and 2002, were also included in the search. Prior to data extraction, concepts like nephrotoxicity, infusion-related adverse events and efficacy (success rate and mortality) were defined.

RESULTS

Two studies comparing liposomal amphotericin B with conventional amphotericin B, one comparing liposomal amphotericin B with amphotericin B lipid complex and one comparing liposomal amphotericin B with voriconazol were included in the analysis. Patients treated with liposomal amphotericin B had lower nephrotoxicity than patients treated with other amphotericin B formulations or with conventional amphotericin B (RR = 0.49); conversely, no statistically significant differences with regard to voriconazol were observed. In terms of efficacy, mortality rate and therapeutic failure, patients treated with limposomal amphotericin B showed a slightly higher efficacy.

CONCLUSIONS

Liposomal amphotericin B is a lipidic formulation with a slightly higher efficacy than other amphotericin B formulations and voriconazol. In terms of nephrotoxicity, liposomal amphotericin B showed lower nephrotoxicity than other amphotericines while its safety rates were similar to those of voriconazol.