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

Liposomal amphotericin B (AmBisome) for fungal infections in immunocompromised adults and children

Invasive fungal infections are rare but life-threatening infections, most often occurring in immunocompromised patients. For a long time, Amphotericin B has been the best choice for treatment, because it is fungicidal with a broad antifungal spectrum and minimal risk of resistance development. The therapeutic use of amphotericin B has, however, been limited by its toxicity-both acute as well as chronic. To counter this, amphotericin B has been encapsulated in liposomes, which reduces its toxicity and allows higher doses to be given. Ambisome is a true, spherical, small unilamellar liposome with a median size of 80 nm. The pharmacokinetic profile was changed, and the maximum concentration and AUC of amphotericin B after AmBisome treatment were greater than those found with the conventional drug. The highest tissue concentrations of AmBisome were found in the liver and spleen, and less than 1% of the administered dose was recovered in other organs. At Huddinge University Hospital, we were the first to use and report on the experience of AmBisome. We now have more than 12 years' experience in transplant recipients, with a good safety profile, improved rate of curing mycological proven infections and reduced mortality in fungal infections. In two placebo-controlled prophylactic trials, we found that AmBisome was effective for preventing fungal colonization and invasive fungal infections, respectively, in allogeneic stem cell and liver transplantation. In uncontrolled and, more recently, in randomized controlled studies at other centers, AmBisome has revealed less toxicity and an efficacy equal or superior to that of the conventional drug in treating neutropenia-associated fever and proven invasive fungal infections in both adults as well as in children. Although investigators tend to increase the dose used, the optimal dose for probable or proven infection is still under debate. Based on our own experience in using AmBisome and the experience at other centers, we can conclude that AmBisome represents a major breakthrough in the treatment of invasive fungal infections, especially in immunocompromised patients.

Efficacy of TAK-457, a novel intravenous triazole, against invasive pulmonary Aspergillosis in neutropenic mice

TAK-457 is an injectable prodrug of TAK-456, which is a novel oral triazole compound with potent antifungal activity. The in vivo efficacy of TAK-457 was evaluated in two models of invasive pulmonary aspergillosis with CDF(1) mice and CBA/J mice with transient neutropenia induced by cyclophosphamide. Against the infection in CDF(1) mice, treatment with 10 mg of TAK-457 and 1 mg of amphotericin B/kg reduced the fungal burden in lungs and rescued all mice. In the infection model with CBA/J mice, TAK-457 at a dose of 10 mg/kg significantly prolonged the survival time of mice, showing significant reduction of lung chitin levels and the plasma beta-D-glucan levels. On the other hand, amphotericin B at 1 mg/kg which was a maximum tolerable dose showed slight but not significant prolongation of survival time of mice, although it also reduced the lung chitin levels and the plasma beta-D-glucan levels to a lower extent but still significantly. These results suggest that TAK-457 is a promising candidate for development for the treatment of invasive aspergillosis in humans.

Voriconazole compared with liposomal amphotericin B for empirical antifungal therapy in patients with neutropenia and persistent fever

BACKGROUND

Patients with neutropenia and persistent fever are often treated empirically with amphotericin B or liposomal amphotericin B to prevent invasive fungal infections. Antifungal triazoles offer a potentially safer and effective alternative.

METHODS

In a randomized, international, multicenter trial, we compared voriconazole, a new second-generation triazole, with liposomal amphotericin B for empirical antifungal therapy.

RESULTS

A total of 837 patients (415 assigned to voriconazole and 422 to liposomal amphotericin B) were evaluated for success of treatment. The overall success rates were 26.0 percent with voriconazole and 30.6 percent with liposomal amphotericin B (95 percent confidence interval for the difference, -10.6 to 1.6 percentage points); these rates were independent of the administration of antifungal prophylaxis or the use of colony-stimulating factors. There were fewer documented breakthrough fungal infections in patients treated with voriconazole than in those treated with liposomal amphotericin B (8 [1.9 percent] vs. 21 [5.0 percent], P=0.02). The voriconazole group had fewer cases of severe infusion-related reactions (P<0.01) and of nephrotoxicity (P<0.001). The incidence of hepatotoxicity was similar in the two groups. Patients receiving voriconazole had more episodes of transient visual changes than those receiving liposomal amphotericin B (22 percent vs. 1 percent, P<0.001) and more hallucinations (4.3 percent vs. 0.5 percent, P<0.001). Parenteral voriconazole was changed to the oral formulation in 22 percent of the voriconazole group, with a reduction in the mean duration of hospitalization by one day in all patients (P=0.17) but by two days in patients at high risk (P=0.03).

CONCLUSIONS

Voriconazole is a suitable alternative to amphotericin B preparations for empirical antifungal therapy in patients with neutropenia and persistent fever.

Liposomal amphotericin B (AmBisome) compared with amphotericin B +/- FMLP induces significantly less in vitro neutrophil aggregation with granulocyte-colony-stimulating factor/dexamethasone-mobilized allogeneic donor neutrophils

Concomitant use of allogeneic donor granulocyte transfusions and amphotericin B in febrile neutropenic recipients may be limited by the increased incidence of respiratory distress. In vitro effects of amphotericin B and AmBisome were compared on polymorphonuclear leukocyte (PMN) aggregation from PMNs isolated from granulocyte-colony-stimulating factor (G-CSF)/dexamethasone-mobilized allogeneic donors. Six allogeneic donors were mobilized with G-CSF (600 microg subcutaneously) and dexamethasone (8 mg orally) 12 hours before leukopheresis. AmBisome was associated with significantly less PMN aggregation (100 microM [microg/mL]) (0.33% +/- 0.33% vs 54.33% +/- 5.82%; P <.001) than amphotericin B. Furthermore, with the addition of the PMN agonist, FMLP, AmBisome was also associated with significantly less aggregation (100 microM [microg/mL]) (18.67% +/- 1.45% vs 54.67% +/- 2.4%; P <.001). In summary, these studies demonstrate that liposomal amphotericin is associated with significantly less in vitro PMN aggregation than amphotericin B and could possibly be administered concomitantly with mobilized allogeneic PMN infusions.

Safety, tolerance, and pharmacokinetics of high-dose liposomal amphotericin B (AmBisome) in patients infected with Aspergillus species and other filamentous fungi: maximum tolerated dose study

We conducted a phase I-II study of the safety, tolerance, and plasma pharmacokinetics of liposomal amphotericin B (L-AMB; AmBisome) in order to determine its maximally tolerated dosage (MTD) in patients with infections due to Aspergillus spp. and other filamentous fungi. Dosage cohorts consisted of 7.5, 10.0, 12.5, and 15.0 mg/kg of body weight/day; a total of 44 patients were enrolled, of which 21 had a proven or probable infection (13 aspergillosis, 5 zygomycosis, 3 fusariosis). The MTD of L-AMB was at least 15 mg/kg/day. Infusion-related reactions of fever occurred in 8 (19%) and chills and/or rigors occurred in 5 (12%) of 43 patients. Three patients developed a syndrome of substernal chest tightness, dyspnea, and flank pain, which was relieved by diphenhydramine. Serum creatinine increased two times above baseline in 32% of the patients, but this was not dose related. Hepatotoxicity developed in one patient. Steady-state plasma pharmacokinetics were achieved by day 7. The maximum concentration of drug in plasma (C(max)) of L-AMB in the dosage cohorts of 7.5, 10.0, 12.5, and 15.0 mg/kg/day changed to 76, 120, 116, and 105 microg/ml, respectively, and the mean area under the concentration-time curve at 24 h (AUC(24)) changed to 692, 1,062, 860, and 554 microg x h/ml, respectively, while mean CL changed to 23, 18, 16, and 25 ml/h/kg, respectively. These data indicate that L-AMB follows dose-related changes in disposition processing (e.g., clearance) at dosages of >or=7.5 mg/kg/day. Because several extremely ill patients had early death, success was determined for both the modified intent-to-treat and evaluable (7 days of therapy) populations. Response rates (defined as complete response and partial response) were similar for proven and probable infections. Response and stabilization, respectively, were achieved in 36 and 16% of the patients in the modified intent-to-treat population (n = 43) and in 52 and 13% of the patients in the 7-day evaluable population (n = 31). These findings indicate that L-AMB at dosages as high as 15 mg/kg/day follows nonlinear saturation-like kinetics, is well tolerated, and can provide effective therapy for aspergillosis and other filamentous fungal infections.

Liposomal amphotericin B for prophylaxis of invasive fungal infections in high-risk paediatric patients with chemotherapy-related neutropenia: interim analysis of a prospective study

Invasive fungal infections (IFI) are a major cause of morbidity and mortality in patients with cancer. A retrospective analysis of children with cancer at high risk for IFI treated at Münster University Hospital showed that the incidence (7.4% vs. 1.8%) and lethality (28.1% vs. 0) of documented IFI were lower in patients receiving systemic antifungal prophylaxis with liposomal amphotericin B (l-AmB) in comparison to a historical control group. To determine whether this decline in incidence and lethality was due to antifungal prophylaxis or was produced by advances in diagnostic procedures and early empirical antifungal therapy, a prospective study was initiated. Patients in the prophylaxis arm received thrice-weekly 1 mg kg(-1) body weight l-AmB, whilst patients in the early intervention arm received no prophylaxis. Diagnostic procedures and antifungal therapy for suspected or proven IFI were initiated as clinically indicated for all patients. The primary endpoint of the study was the incidence of IFI. Secondary endpoints were the use of therapeutic doses of l-AmB, the safety of prophylactic l-AmB, and the total consumption of l-AmB for antifungal therapy. The interim analysis after 1 year showed no differences between the two approaches with respect to the incidence of IFI and to safety issues.

Can we decrease amphotericin nephrotoxicity?

Amphotericin B (AmB) is considered the drug of choice for the treatment of systemic fungal infections. Nephrotoxicity is a major complication associated with its use, and appears to be related to higher cumulative doses, diuretic use, abnormal serum creatinine at baseline, and the use of concomitant nephrotoxic drugs. The two major hypotheses for the pathogenesis of AmB-related nephrotoxicity are direct effects of the drug on epithelial cell membranes and vasoconstriction. During the last few years, some randomized trials have tested different strategies to reduce AmB-induced renal toxicity. These strategies include sodium supplementation, low-dose dopamine, slower infusion rates, the administration of AmB in lipid emulsions, and in lipid formulations. The results of these trials showed that the lipid formulations of AmB significantly reduce nephrotoxicity. Unfortunately, these agents are costly, restricting their use to patients with a high risk of developing renal failure.

Improving efficacy of antifungal therapy by polymerase chain reaction-based strategy among febrile patients with neutropenia and cancer

Early detection of fungal infections in and corresponding early treatment of febrile patients with neutropenia and cancer have been important issues and continue to be major challenges for clinicians. The use of nested PCR to make therapeutic decisions was studied. Sequential blood samples obtained from 42 patients with neutropenia and cancer were tested by nested PCR and culture. Instead of the empirical antifungal therapy strategy, amphotericin B treatment was initiated only for patients who had 2 consecutive positive results by nested PCR. A reduced mortality rate was observed for febrile patients with neutropenia and cancer who had fungal infections. Thus, this strategy, combined with the nested PCR for early detection of fungal infection in febrile patients with neutropenia, may be used as a guideline for antifungal therapy.

Treatment of systemic fungal infections in older patients: achieving optimal outcomes

Systemic fungal infections are an increasing problem in older adults. For several of the endemic mycoses, this increase is the result of increased travel and leisure activities in areas endemic for these fungi. Immunosuppressive agents, care in an intensive care unit, and invasive devices all contribute to infection with opportunistic fungi. Treatment of systemic fungal infections is usually with an azole or amphotericin B. The preferred regimen depends on the specific fungal infection, the site and the severity of the infection, the state of immunosuppression of the patient and the possible toxicities of each drug for a specific patient. In older adults, drug-drug interactions between the azoles and drugs commonly prescribed for older persons may lead to serious toxicity, and absorption of itraconazole can be problematic. Amphotericin B is associated with significant nephrotoxicity, especially in older adults with pre-existing renal disease, and infusion-related adverse effects. Newer lipid formulations of amphotericin B can obviate some of these toxicities, but their role in the treatment of systemic fungal infections in older adults has not yet been clarified.

The epidemiology of nephrotoxicity associated with conventional amphotericin B therapy

PURPOSE

We sought to quantify the incidence of, define risk factors for, and examine the relation between renal functional impairment and treatment with conventional amphotericin B.

SUBJECTS AND METHODS

We performed a 9-year retrospective analysis of amphotericin B-associated nephrotoxicity in 494 adult inpatients who received > or = 2 doses of amphotericin B. Nephrotoxicity was classified according to two nonmutually exclusive severity categories (50% increase or doubling in the baseline creatinine level).

RESULTS

The median cumulative dosage of amphotericin B was 240 mg (interquartile range, 113 to 500 mg), with the majority of patients (n = 361) receiving it for empiric treatment. Overall, 139 (28%) patients experienced renal toxicity, including 58 (12%) with moderate-to-severe nephrotoxicity. The rate of nephrotoxicity was relatively constant during amphotericin B treatment. For each 10-mg increase in the mean daily amphotericin B dose, the adjusted rate of renal toxicity increased by a factor of 1.13 (95% confidence interval: 1.02 to 1.25). We defined 5 categorical risk factors: mean daily amphotericin B dose > or = 35 mg, male sex, weight > or = 90 kg, chronic renal disease, and use of amikacin or cyclosporine. The incidence of moderate-to-severe nephrotoxicity was 4% (6 of 137) in patients with none of these risk factors, 8% (14 of 181) in those with 1 risk factor, 18% (21 of 117) in those with 2 risk factors, and 29% (17 of 59) in patients with > or = 3 risk factors. Nephrotoxicity rarely led to hemodialysis (n = 3); however, at the time of discharge or death, 70% of patients with moderate-to-severe nephrotoxicity had a serum creatinine level that was > or = 0.5 mg/dL above baseline.

CONCLUSION

Amphotericin B-related nephrotoxicity is an important dose-dependent and duration-dependent toxicity that is accentuated by certain nephrotoxic drugs and patient characteristics. Patients with more than two risk factors for nephrotoxicity are potential candidates for alternative antifungal therapy.

Treatment of documented and suspected neutropenia-associated invasive fungal infections

Factors such as the intensification of anti-tumor regimens have enhanced both the depth and length of neutropenia and endorsed severe deficiencies in other immune systems. As a result, the risk of fungal infections has increased substantially. Clinicians should be aware of the possibility to enable a timely diagnosis because many of the problems in the management of invasive fungal infections during neutropenia are as much the consequence of diagnostic short-comings as of lack of therapeutic options. About 7% of all febrile episodes during neutropenia can ultimately be attributed to fungi, Candida and Aspergillus species being the paramount pathogens. Although the data in favor of prophylactic use of antifungals are not convincing, prophylaxis is still recommended in an attempt to protect particularly high-risk patients. Fluconazole still appears a suitable agent in recipients of a bone marrow transplant. Given the paucity of data, reappraisal of the value of empirical antifungal therapy is warranted. Amphotericin B with or without 5-flucytosine is considered the standard therapy for acute candidiasis with fluconazole as an alternative. Amphotericin B is also first-line therapy for invasive aspergillosis in neutropenic patients; lipid-based formulations are recommended for patients who develop nephrotoxity. Recovery of the granulocytes and other immune systems has shown to be of critical importance in the management of all invasive fungal infections.

Pulmonary reactions during treatment with amphotericin B: review of published cases and guidelines for management

Acute respiratory events occasionally have been observed during the infusion of amphotericin B. Herein we analyze the 21 cases that have been reported, including a fatal reaction observed by us. Some useful guidelines are provided that likely will allow treatment to be continued safely for patients who have experienced such reactions.

Detection of Aspergillus species in blood and bronchoalveolar lavage samples from immunocompromised patients by means of 2-step polymerase chain reaction: clinical results

Bronchoalveolar lavage (BAL) samples from 67 patients who were at high risk for invasive aspergillosis were examined using a recently developed 2-step polymerase chain reaction (PCR) that detects </=10 fg of Aspergillus DNA in blood and BAL samples in vitro. Thirteen of these patients had PCR and diagnostic results positive for Aspergillus infection. Four patients with possible invasive aspergillosis also had positive PCR results, and the remaining 50 had negative PCR results. In addition, 907 blood samples from 218 high-risk patients were screened. Thirty-three patients with positive PCR results had invasive aspergillosis; 148 patients had PCR and diagnostic results that were negative, and 34 patients with positive PCR results had nonconclusive clinical data. Both blood and BAL testing were performed for 45 patients. All 8 patients with proven invasive aspergillosis showed concordance of positive PCR results. Our data suggest that this PCR method has possible clinical value for confirming and improving the diagnosis of invasive aspergillosis in high-risk patients.

Optimal use of existing and new antifungal drugs

Clinicians are increasingly aware that fungal pathogens are a significant cause of morbidity and mortality in hospitalized patients. Historically, these infections occurred in severely immunocompromised patients who were undergoing treatment for hematological malignancy or solid organ transplantation. Currently, however, systemic fungal infections are commonly seen in debilitated patients who are being nursed in intensive care or high-dependency units. These infections are mostly caused by Candida albicans but there is a growing proportion of strains of non- albicans Candida spp, some with reduced susceptibility to commonly used antifungals. The limited armamentarium of antifungal agents to date has meant that amphotericin B continues to be considered the most effective therapeutic agent albeit with a poor record of treatment-limiting side effects. The past decade has seen some encouraging developments in antifungal therapy. Three lipid formulations of amphotericin B showing reduced toxicity compared with the desoxycholate formulation are now licensed. There are three investigational triazoles currently undergoing evaluation that should prove important additions to existing members of this class. The echinocandin caspofungin is the first of a new class of antifungal agents with a novel mode of action, which has recently been approved for use in the United States.

A clinical perspective for the management of invasive fungal infections: focus on IDSA guidelines. Infectious Diseases Society of America

Invasive fungal infections, especially candidiasis and aspergillosis, are a major cause of morbidity and mortality. Many controversies surround the management of these infections. A critical overview of the recent Infectious Diseases Society of America practice guidelines is provided, as are comments on both the conundrums and future perspectives in medical mycology.

Successful treatment of invasive mould infection affecting lung and brain in an adult suffering from acute leukaemia

We describe in detail a 67-yr-old woman who was treated with a cytostatic combination chemotherapy for newly diagnosed common-acute lymphoblastic leukaemia. At the end of induction therapy, the patient acquired invasive mould infection affecting lung and brain. The patient entered complete remission of her leukaemia. Treatment with liposomal amphotericin B was initiated along with surgical excision of the fungal brain abscess. Intrathecal instillation of amphotericin B deoxycholate was started using an Ommaya reservoir because of an anatomical connection between the postoperative cavity and the ventricle. Full dose cytostatic chemotherapy was continued with little delay. A computerised tomography scan of the chest performed 2 months later revealed no fungal abscesses. Magnetic resonance imaging of the brain did not reveal any fungal manifestation. During maintenance therapy/week 69, the patient relapsed from leukaemia. High doses of intravenous liposomal amphotericin B were administered prophylactically. The patient's leukaemia proved refractory to reinduction chemotherapy and the patient died from pneumonia 8 wk later. Post mortem microbiological investigation and histopathological examination of lung and brain tissue did not reveal any macroscopical or microscopical fungal manifestations. This case underlines the feasibility and successful application of combined antileukaemic, antifungal and surgical therapy in a patient with acute leukaemia.

Need for alternative trial designs and evaluation strategies for therapeutic studies of invasive mycoses

Studies of invasive fungal infections have been and remain difficult to implement. Randomized clinical trials of fungal infections are especially slow and expensive to perform because it is difficult to identify eligible patients in a timely fashion, to prove the presence of the fungal infection in an unequivocal fashion, and to evaluate outcome in a convincing fashion. Because of these challenges, licensing decisions for antifungal agents have to date depended heavily on historical control comparisons and secondary advantages of the new agent. Although the availability of newer and potentially more effective agents makes these approaches less desirable, the fundamental difficulties of trials of invasive fungal infections have not changed. Therefore, there is a need for alternative trial designs and evaluation strategies for therapeutic studies of invasive mycoses, and this article summarizes the possible strategies in this area.

Infectious morbidity in critically ill patients with cancer

Infection frequently complicates the course of cancer treatment and often adversely affects the outcome. Patients have a greater tendency for acquiring infections caused by opportunistic microorganisms. Agents with low virulence potential may lead to invasive and often life-threatening infections because of altered host immune function. The immune dysfunction may be caused by the underlying malignancy, by antineoplastic chemotherapy, or by invasive procedures during supportive care.

Infectious complications of febrile leukopenia

It can be foreseen that in the years to come major improvements in neutropenic host infections will be achieved regarding the exact identification of risk factors, allowing better patient stratification; the application of molecular techniques to recognize pathogens; the development of effective new oral antimicrobials allowing home therapy or abbreviated hospitalization; the development of new antifungals; and the development of new effective immunomodulators and cytokines to ameliorate chemotherapy-induced neutropenia. In the years to come the threat of nosocomial infections unfortunately will not be eliminated, while the development of major new parenteral antibiotics cannot be foreseen. It is therefore the caregiver/physician himself who, by applying rational antibiotic policies and strict handwashing rules, will probably escape, for his neutropenic patient's sake, the imminent threat of multiresistant pathogens.

Long term improvement in the treatment of canine leishmaniosis using an antimony liposomal formulation

Pharmacokinetic and clinical effectiveness of liposome-encapsulated N-methylglucamine antimoniate (LMA) was performed in dogs suffering from experimental leishmaniosis. LMA was compared with N-methylglucamine antimoniate (MGA), the same drug in its free form. Sb plasma concentrations for LMA were always higher than those for MGA. Mean residence time (MRT), half-life time (t(1/2)) and clearance (Cl) showed that Sb was eliminated slower after liposome administration. The high volume of distribution (Vd) obtained with LMA suggests that Sb could achieve therapeutic concentrations in parasite-infected tissues. Average plasma concentration at steady state (Css(ave)) shows that Sb body concentrations after LMA treatment (9.8 mg/kg Sb, each 24h) would be effective in Leishmania infantum canine infection. Comparing LMA with MGA in a 1-year follow-up we observed no relapses for LMA and total protein and gammaglobulin concentrations were within normal range, while for MGA both began to rise 3 months after treatment. Use of antimonial liposomal formulations may restore effectiveness to an existing drug and reduce toxicity.

Therapy for fungal infections in leukemia

Invasive fungal infections remain a common cause of morbidity and mortality among patients with leukemia who become further compromised by neutropenia. Candida and Aspergillus spp account for the vast majority of these infections, but other, less commonly recognized fungi can cause life-threatening infection in these hosts as well. The earlier, more limited antifungal armamentarium of ketoconazole, flucytosine, and amphotericin B has been substantially augmented by the availability of fluconazole, itraconazole, and the lipid-associated amphotericin formulations. Intense clinical study has focused on the use of these agents in empiric treatment, treatment of suspected or proven infection, and prophylaxis. Recognition of the limitations of antifungal therapy in the neutropenic host has led to evaluation of the adjunctive role of immunotherapy.

The cost of treating systemic fungal infections

The increasing incidence of systemic fungal infections and rising medical costs have highlighted the need for an economic appraisal of antifungal agents to determine the most cost-effective therapeutic option. Cost savings derived from the prophylactic or empirical use of antifungal agents have been difficult to estimate because of the lack of information on the costs of systemic fungal infections. Fluconazole is effective in prophylaxis and represents a direct cost saving compared with polyenes. However, itraconazole oral solution, an effective and widely used antifungal prophylactic agent, has not been analysed for cost effectiveness. In empirical therapy, the development of new formulations of existing agents has prompted a number of cost comparisons. In particular, the cost of treatment with conventional amphotericin-B has been compared with the costs of the new lipid-associated formulations of amphotericin-B or the new intravenous (IV) formulation of itraconazole. The acquisition costs of lipid-associated amphotericin-B and IV itraconazole are higher than the cost of conventional amphotericin-B; however, these costs appear to be offset by reductions with both these agents in the cost for increased length of hospital stay and treating adverse events seen with conventional amphotericin-B. In neutropenic patients and bone marrow transplant recipients, IV itraconazole may be the most cost-effective option for empirical therapy.

Current management of fungal infections

The management of superficial fungal infections differs significantly from the management of systemic fungal infections. Most superficial infections are treated with topical antifungal agents, the choice of agent being determined by the site and extent of the infection and by the causative organism, which is usually readily identifiable. One exception is onychomycosis, which usually requires treatment with systemically available antifungals; the accumulation of terbinafine and itraconazole in keratinous tissues makes them ideal agents for the treatment of onychomycosis. Oral candidiasis in immunocompromised patients also requires systemic treatment; oral fluconazole and itraconazole oral solution are highly effective in this setting. Systemic fungal infections are difficult to diagnose and are usually managed with prophylaxis or empirical therapy. Fluconazole and itraconazole are widely used in chemoprophylaxis because of their favourable oral bioavailability and safety profiles. In empirical therapy, lipid-associated formulations of amphotericin-B and intravenous itraconazole are safer than, and at least as effective as, conventional amphotericin-B (the former gold standard). The high acquisition costs of the lipid-associated formulations of amphotericin-B have limited their use.

Clinical experience with itraconazole in systemic fungal infections

The broad spectrum antifungal itraconazole is an effective and well tolerated agent for the prophylaxis and treatment of systemic fungal infections. The recent development of an itraconazole oral solution and an intravenous itraconazole solution has increased the options for the use of this drug and increased the oral bioavailability in a variety of at-risk patients. Reliable absorption of the itraconazole oral solution has been demonstrated in patients with HIV infection, neutropenic patients with haematological malignancy, bone marrow transplant recipients and neutropenic children. In clinical trials, itraconazole oral solution (5 mg/kg/day) was more effective at preventing systemic fungal infection in patients with haematological malignancy than placebo, fluconazole suspension (100 mg/day) or oral amphotericin-B (2 g/kg/day) and was highly effective at preventing fungal infections in liver transplant recipients. There were no unexpected adverse events with the itraconazole oral solution in any of these trials. In addition, intravenous itraconazole solution is at least as effective as intravenous amphotericin-B in the empirical treatment of neutropenic patients with systemic fungal infections, and drug-related adverse events are more frequent in patients treated with amphotericin-B. A large proportion of patients with confirmed aspergillosis also respond to treatment with intravenous itraconazole followed by oral itraconazole. The new formulations of itraconazole are therefore effective agents for prophylaxis and treatment of most systemic fungal infections in patients with haematological malignancy.

[Antifungal drugs in the treatment of systemic candidiasis: susceptibility to antifungal drugs, drug resistance, pharmacological data]

The available antifungal agents are amphotericin B (conventional or lipid formulation), flucytosin and azole derivatives (ketoconazole, fluconazole, itraconazole). The main target of these molecules are a specific compound of fungal membrane, ergosterol. Determination of the fungal sensitivity to antifungal drugs is difficult and no consensus has been achieved so far. Minimal inhibitory concentrations are poor predictors of clinical success or failure. A good correlation between in vitro and in vivo results has been observed only in patients with oropharyngeal candidiasis associated with HIV infection. Combinations of antifungal drugs are currently under study. The role of hemopoietic growth factors (G-CSF, GM-CSF) as an adjuvant has not been fully established. New antifungal drugs (triazole derivatives, echinocandins) should be available within months.

Screening for circulating galactomannan as a noninvasive diagnostic tool for invasive aspergillosis in prolonged neutropenic patients and stem cell transplantation recipients: a prospective validation

The diagnosis of invasive aspergillosis (IA) in patients with hematologic disorders is not straightforward; lack of sensitive and specific noninvasive diagnostic tests remains a major obstacle for establishing a precise diagnosis. In a series of 362 consecutive high-risk treatment episodes that were stratified according to the probability of IA based on recently accepted case definition sets, the potential for diagnosis of serial screening for circulating galactomannan (GM), a major aspergillar cell wall constituent was validated. After incorporating postmortem findings to allow a more accurate final analysis, this approach proved to have a sensitivity of 89.7% and a specificity of 98.1%. The positive and negative predictive values equaled 87.5% and 98.4%, respectively. False-positive reactions occurred at a rate of 14%, although this figure might be overestimated due to diagnostic uncertainty. More or less stringent criteria of estimation could highly influence sensitivity, which ranged from 100% to 42%; the impact on other test statistics was far less dramatic. All proven cases of IA, including 23 cases confirmed after autopsy only, had been detected before death, although serial sampling appeared to be necessary to maximize detection. The excellent sensitivity and negative predictive value makes this approach suitable for clinical decision making. Unfortunately, given the species-specificity of the assay, some emerging non-Aspergillus mycoses were not detected. In conclusion, serial screening for GM, complemented by appropriate imaging techniques, is a sensitive and noninvasive tool for the early diagnosis of IA in high-risk adult hematology patients.

Comparison of effects of amphotericin B deoxycholate infused over 4 or 24 hours: randomised controlled trial

OBJECTIVE

To test the hypothesis that amphotericin B deoxycholate is less toxic when given by continuous infusion than by conventional rapid infusion.

DESIGN

Randomised, controlled, non-blinded, single centre study.

SETTING

University hospital providing tertiary clinical care.

PATIENTS

80 mostly neutropenic patients with refractory fever and suspected or proved invasive fungal infections.

INTERVENTION

Patients were randomised to receive 0.97 mg/kg amphotericin B by continuous infusion over 24 hours or 0.95 mg/kg by rapid infusion over four hours.

MAIN OUTCOME MEASURES

Patients were evaluated for side effects related to infusion, nephrotoxicity, and mortality up to three months after treatment. Analysis was on an intention to treat basis.

RESULTS

Patients in the continuous infusion group had fewer side effects and significantly reduced nephrotoxicity than those in the rapid infusion group. Overall mortality was higher during treatment and after three months' follow up in the rapid infusion than in the continuous infusion group.

CONCLUSION

Continuous infusions of amphotericin B reduce nephrotoxicity and side effects related to infusion without increasing mortality.

Lipid-based amphotericin B: a review of the last 10 years of use

The last decade has been remarkable for the dramatic increase in the prevalence of serious fungal infections in patients with haematological disorders and neutropenic cancer patients. The mortality rate of deep-seated infection has been in excess of 90% and there is no doubt that this is one of the greatest challenges currently facing haematologists and oncologists. The development of the lipid-based drugs - liposomal amphotericin (AmBisome(R)), amphotericin B lipid complex, ABLC (Abelcet(R)), amphotericin B colloidal dispersion, Amphocil (ABCD(R)), has meant that doses of amphotericin B can be safely escalated for the first time whilst the problems of nephrotoxicity, infusion related reactions (including chills, rigors, fevers and hypoxia) can be reduced. These toxicities are variably reduced with AmBisome more than Abelcet and more than Amphocil and there is little information from randomised trials other than for AmBisome. AmBisome used in the setting of persistent fever and neutropenia not responding after 3-4 days of intravenous antibiotics, is associated with less breakthrough systemic fungal infections. There is also much less need for premedication, including steroids, compared with amphotericin B and Abelcet. The use of intermittent doses of Ambisome given prophylactically is now being explored. A new and exciting era of antifungal therapy is opening up with new compounds, such as itraconazole voriconazole, posaconazole and echinocandins, being investigated and for the first time, we also have options for combination therapy and prophylaxis.

Oral antifungals as prophylaxis in haematological malignancy

In the standard treatment of patients with haematological malignancy, immunosuppressive therapy produces prolonged periods of neutropenia and mucositis, which increase the risk of systemic fungal infection. In allogeneic bone marrow transplantation, this risk extends well beyond the period of neutropenia when graft-versus-host disease, and its treatment, result in prolonged lymphocytopenia. Various agents are used for antifungal prophylaxis and treatment but all have limitations: amphotericin B is restricted by the need for intravenous infusion and the occurrence of adverse events, fluconazole by its narrow spectrum of activity and the emergence of fluconazole-resistant fungi and itraconazole capsules by erratic absorption. Oral administration of antifungals has clear advantages in prophylaxis and an important current strategy is to maximize the extent and reliability of the oral bioavailability of antifungal agents. Mucositis is the main obstacle for success of strategies based on oral delivery. In this review, the ability of these new oral formulations to deliver sufficient antifungal prophylaxis is evaluated.

Amphotericin B--not so terrible

OBJECTIVE

To describe a patient who developed adverse reactions to two different lipid formulations of amphotericin B: liposomal amphotericin B (AmBisome) and amphotericin B colloidal dispersion (ABCD, Amphocil), yet tolerated amphotericin B deoxycholate (Fungizone) despite renal toxicity.

CASE SUMMARY

A 72-year-old woman with acute myelomonocytic leukemia was treated with amphotericin B deoxycholate for suspected pulmonary aspergillosis; the drug was well tolerated but resulted in renal failure. Antifungal therapy was then changed to liposomal amphotericin B. Within 10 minutes of liposomal amphotericin B infusion, the patient developed severe dyspnea, chest pain, and a feeling of imminent death. On the following day, liposomal amphotericin B was switched to amphotericin B colloidal dispersion. Again, within 10 minutes of this infusion, the patient developed fever, chills, hypotension, severe chest pain, dsypnea, and a feeling of imminent death. The patient refused any further treatment with these drugs and insisted on switching back to amphotericin B deoxycholate, which was then administered for 10 days and was well tolerated.

DISCUSSION

Severe adverse reactions, such as anaphylaxis, cardiac toxicity, and respiratory failure, following administration of all three lipid formulations of amphotericin B have been reported. In most reported cases, switching to a different lipid formulation of amphotericin B was well tolerated. This is in contrast to our case, where a severe reaction was repeated when another lipid preparation was given, necessitating switching back to amphotericin B deoxycholate despite its nephrotoxicity.

CONCLUSIONS

In some patients, paradoxically, lipid formulations of amphotericin B may be less tolerable than conventional amphotericin B.

Management of fever in neutropenic patients

Substantial progress has been made in the management of febrile episodes in neutropenic patients, largely by the prompt administration of potent, broad-spectrum antimicrobial agents. During the past several decades, the spectrum of organisms has changed from a predominance of gram-negative pathogens to a predominance of gram-positive pathogens. In recent years, some hospitals have experienced an increase of infections caused by multi-drug-resistant pathogens. Hence, it is no longer possible to rely on standardized regimens, but antimicrobial therapy must be selected based on the predominant pathogens and antimicrobial susceptibility patterns at each institution. It is customary to initiate antifungal therapy empirically in those patients whose fever persists despite broad-spectrum antibacterial therapy. Alternatives now exist to amphotericin B, including lipid formulations of this drug, and fluconazole. It is critically important that each patient be carefully re-assessed before starting antifungal therapy, because there are many other potential causes for persistent fever, including resistant bacteria and viruses. Novel approaches to therapy include outpatient antibiotics, and use of growth factors as adjunctive therapy. There also has been a renewed interest in white blood cell transfusions. Although the prognosis for infection in neutropenic patients has improved greatly, new infectious problems have emerged that limit our successful management of these complications.

Mortality and costs of acute renal failure associated with amphotericin B therapy

To assess the mortality and resource utilization that results from acute renal failure associated with amphotericin B therapy, 707 adult admissions in which parenteral amphotericin B therapy was given were studied at a tertiary-care hospital. Main outcome measures were mortality, length of stay, and costs; we controlled for potential confounders, including age, sex, insurance status, baseline creatinine level, length of stay before beginning amphotericin B therapy, and severity of illness. Among 707 admissions, there were 212 episodes (30%) of acute renal failure. When renal failure developed, the mortality rate was much higher: 54% versus 16% (adjusted odds of death, 6.6). When acute renal failure occurred, the mean adjusted increase in length of stay was 8.2 days, and the adjusted total cost was $29,823. Although residual confounding exists despite adjustment, the increases in resource utilization that we found are large and the associated mortality is high when acute renal failure occurs following amphotericin B therapy.

Practice guidelines for lipid-based amphotericin B in stem cell transplant recipients

OBJECTIVE

To provide clinicians who practice in the stem cell transplantation (SCT) setting with practical guidelines for the use of lipid-based amphotericin B (AmB) formulations in SCT patients who have documented or probable invasive fungal infections, are experiencing neutropenic fever, or require secondary prophylaxis for fungal infections.

DATA SOURCES

Recommendations are based on the results of a two-day consensus meeting that convened clinicians versed in the management of infectious complications in patients undergoing SCT. This meeting, which was held October 21-23, 1998, in Orlando, Florida, was sponsored by an educational grant from The Liposome Company. In addition, primary articles were identified by MEDLINE search (1980-December 1999) and through secondary sources.

STUDY SELECTION AND DATA EXTRACTION

All of the articles identified from the data sources were evaluated, and all information deemed relevant was included in this review.

DATA SYNTHESIS

Immunocompromised patients, particularly patients undergoing high-dose chemotherapy with SCT, experience a high degree of morbidity and mortality from invasive fungal infections. Historically, treatment for such infections with conventional AmB had been limited primarily by its associated nephrotoxicity. Lipid-based formulations of AmB have helped to advance the management of invasive fungal infections in the SCT population by offering a treatment alternative that allows for administration of adequate amounts of active drug to produce clinical and mycologic responses, compared with conventional AmB, in a delivery system that is less nephrotoxic. Unfortunately, these agents are relatively expensive. Therefore, patients who are candidates for lipid-based products must be selected carefully.

CONCLUSIONS

Practical guidelines are provided for the use of lipid-based AmB formulations in SCT patients who have documented or probable invasive fungal infections, are experiencing neutropenic fever, or require secondary prophylaxis for fungal infections.

[New lipid formulations of amphotericin B. Review of the literature]

INTRODUCTION

Amphotericin B (amB) remains the gold standard for treatment of invasive fungal infections. Lipid formulations of amB have been developed in an attempt to improve both efficacy and tolerability (especially renal toxicity): amB lipid complex (ABLC), liposomal amB (AmBisome), amB colloidal dispersion (ABCD) and amB in lipid emulsion (Intralipid). This review analyzes the data available in the literature.

CURRENT KNOWLEDGE AND KEY POINTS

ABLC, AmBisome and ABCD are effective in various fungal infections, including invasive aspergillosis, systemic candidiasis, cryptococcal meningitis, mucormycosis and fusariosis. These formulations are also effective in persistent febrile neutropenia and in leishmaniosis. The three formulations show little renal toxicity and are safer than conventional amB in this respect. Preliminary data are available on amB in Intralipid: infusion-related adverse effects are reduced, but few data are available on efficacy in documented mycoses.

FUTURE PROSPECTS AND PROJECTS

Large-scale comparative clinical trials may clarify issues of relative efficacy in various forms of fungal infections.

Preventing opportunistic infections after hematopoietic stem cell transplantation: the Centers for Disease Control and Prevention, Infectious Diseases Society of America, and American Society for Blood and Marrow Transplantation Practice Guidelines and beyond

This review presents evidence-based guidelines for the prevention of infection after blood and marrow transplantation. Recommendations apply to all myeloablative transplants regardless of recipient (adult or child), type (allogeneic or autologous) or source (peripheral blood, marrow or cord blood) of transplant. In Section I, Dr. Dykewicz describes the methods used to rate the strength and quality of published evidence supporting these recommendations and details the two dozen scholarly societies and federal agencies involved in the genesis and review of the guidelines. In Section II, Dr. Longworth presents recommendations for hospital infection control. Hand hygiene, room ventilation, health care worker and visitor policies are detailed along with guidelines for control of specific nosocomial and community-acquired pathogens. In Section III, Dr. Boeckh details effective practices to prevent viral diseases. Leukocyte-depleted blood is recommended for cytomegalovirus (CMV) seronegative allografts, while ganciclovir given as prophylaxis or preemptive therapy based on pp65 antigenemia or DNA assays is advised for individuals at risk for CMV. Guidelines for preventing varicella-zoster virus (VZV), herpes simplex virus (HSV) and community respiratory virus infections are also presented. In Section IV, Drs. Baden and Rubin review means to prevent invasive fungal infections. Hospital design and policy can reduce exposure to air contaminated with fungal spores and fluconazole prophylaxis at 400 mg/day reduces invasive yeast infection. In Section V, Dr. Sepkowitz details effective clinical practices to reduce or prevent bacterial or protozoal disease after transplantation. In Section VI, Dr. Sullivan reviews vaccine-preventable infections and guidelines for active and passive immunizations for stem cell transplant recipients, family members and health care workers.

The changing spectrum of candidemia in oncology patients: therapeutic implications

Infections caused by Candida spp. are frequent and serious in oncology patients. Over the past decade, the introduction of azole antifungals as prophylactic agents, and other factors have caused a shift in the species of Candida that cause infection. During the period under review (June 1999 to June 2000), several studies have been reported that confirm the impact of antifungal prophylaxis and the emergence of non-albicans Candida spp. as pathogens. Moreover, laboratory studies to determine the antifungal susceptibilities and virulence properties of non-albicans Candida spp. have enabled the formation of microbe-specific management strategies. More of these studies will be necessary as we enter an age in which multiple antifungal compounds will become available for clinical use.

Safety, toxicokinetics and tissue distribution of long-term intravenous liposomal amphotericin B (AmBisome): a 91-day study in rats

PURPOSE

Amphotericin B in small, unilamellar liposomes (AmBisome) is safer and produces higher plasma concentrations than other formulations. Because liposomes may increase and prolong tissue exposures, the potential for drug accumulation or delayed toxicity after chronic AmBisome was investigated.

METHODS

Rats (174/sex) received intravenous AmBisome (1, 4, or 12 mg/kg), dextrose, or empty liposomes for 91 days with a 30-day recovery. Safety (including clinical and microscopic pathology) and toxicokinetics in plasma and tissues were evaluated.

RESULTS

Chemical and histopathologic changes demonstrated that the kidneys and liver were the target organs for chronic AmBisome toxicity. Nephrotoxicity was moderate (urean nitrogen [BUN] < or = 51 mg/dl; creatinine unchanged). Liposome-related changes (vacuolated macrophages and hypercholesterolemia) were also observed. Although plasma and tissue accumulation was nonlinear and progressive (clearance and volume decreased, half-life increased with dose and time), most toxic changes occurred early, stabilized by the end of dosing, and reversed during recovery. There were no delayed toxicities. Concentrations in liver and spleen greatly exceeded those in plasma: kidney and lung concentrations were similar to those in plasma. Elimination half-lives were 1-4 weeks in all tissues.

CONCLUSIONS

Despite nonlinear accumulation, AmBisome revealed predictable hepatic and renal toxicities after 91 days, with no new or delayed effects after prolonged treatment at high doses that resulted in plasma levels >200 microg/ml and tissue levels >3000 microg/g.

Successful non-surgical treatment of disseminated polymicrobial fungal infection in a patient with pancytopenia and graft-versus-host disease

Invasive fungal infections after bone marrow transplantation have an extremely poor prognosis. Surgical excision in combination with antifungal therapy is considered necessary for treatment, especially for central nervous system (CNS) infection. We describe successful medical management with lipid complex amphotericin B (ABLC) and itraconazole, without surgical excision, of disseminated fungal infection involving the lungs and CNS in a patient with pancytopenia and graft-versus-host disease.

Fungal infections in patients with neutropenia: challenges in prophylaxis and treatment

Fungal infections are a leading cause of mortality in patients with neutropenia. Candidiasis and aspergillosis account for most invasive fungal infections. General prophylactic measures include strict hygiene and environmental measures. Haemopoietic growth factors shorten the duration of neutropenia and thus may reduce the incidence of fungal infections. Fluconazole is appropriate for antifungal prophylaxis and should be offered to patients with prolonged neutropenia, such as high-risk patients with leukaemia undergoing remission induction or consolidation therapy and high-risk stem cell transplant recipients. Empirical antifungal therapy is mandatory in patients with persistent febrile neutropenia who fail to respond to broad-spectrum antibacterials. Intravenous amphotericin B at a daily dose of 0.6 to 1 mg/kg is preferred whenever aspergillosis cannot be ruled out. Lipid formulations of amphotericin B have demonstrated similar efficacy and are much better tolerated. Fluconazole is the best choice for acute candidiasis in stable patients; amphotericin B should be used in patients with unstable disease. Use of fluconazole is restricted by the existence of resistant strains (Candida krusei and, to a lesser extent, C. glabrata). Amphotericin B still remains the gold standard for invasive aspergillosis. Lipid formulations of amphotericin B are effective in aspergillosis and because they are less nephrotoxic are indicated in patients with poor renal function. Itraconazole is an alternative in patients who have good intestinal function and are able to eat. Mucormycosis, trichosporonosis, fusariosis and cryptococcosis are less common but require specific management. New antifungal agents, especially new azoles, are under development. Their broad in vitro spectrum and preliminary clinical results are promising.