Aerosol amphotericin B for prevention of invasive pulmonary aspergillosis

Inhaled Antifungal Agents for Treatment and Prophylaxis of Bronchopulmonary Invasive Mold Infections

Pulmonary mold infections are life-threatening diseases with high morbi-mortalities. Treatment is based on systemic antifungal agents belonging to the families of polyenes (amphotericin B) and triazoles. Despite this treatment, mortality remains high and the doses of systemic antifungals cannot be increased as they often lead to toxicity. The pulmonary aerosolization of antifungal agents can theoretically increase their concentration at the infectious site, which could improve their efficacy while limiting their systemic exposure and toxicity. However, clinical experience is poor and thus inhaled agent utilization remains unclear in term of indications, drugs, and devices. This comprehensive literature review aims to describe the pharmacokinetic behavior and the efficacy of inhaled antifungal drugs as prophylaxes and curative treatments both in animal models and humans.

Conventional Antifungals for Invasive Infections Delivered by Unconventional Methods; Aerosols, Irrigants, Directed Injections and Impregnated Cement

The administration of approved antifungals via unapproved formulations or administration routes (such as aerosol, direct injection, irrigation, topical formulation and antifungal-impregnated orthopedic beads or cement) may be resorted to in an attempt to optimize drug exposure while minimizing toxicities and/or drug interactions associated with conventional (systemic) administrations. Existing data regarding such administrations are mostly restricted to uncontrolled case reports of patients with diseases refractory to conventional therapies. Attribution of efficacy and tolerability is most often problematic. This review updates prior published summaries, reflecting the most recent data and its application by available prevention and treatment guidelines for invasive fungal infections. Of the various dosage forms and antifungals, perhaps none is more widely reported than the application of amphotericin B-containing aerosols for the prevention of invasive mold infections (notably Aspergillus spp.).

A pilot randomized trial of nebulized amphotericin in patients with allergic bronchopulmonary aspergillosis

BACKGROUND AND AIM

Nebulized amphotericin B (NAB) has been used in the management of acute stage and exacerbations of allergic bronchopulmonary aspergillosis (ABPA). Whether NAB can prevent exacerbations of ABPA is not known. Herein, we evaluate the efficacy and safety of NAB in subjects with ABPA complicating asthma.

METHODS

Consecutive subjects of ABPA with recurrent exacerbations were randomized to receive either NAB plus nebulized budesonide (NEB) or NEB alone. The primary outcome was the time-to-first exacerbation of ABPA. The secondary outcomes were the number of subjects with ABPA exacerbations, ACQ7 scores, lung function, IgE levels, and adverse effects of treatment.

RESULTS

Twenty-one subjects (14 men; mean age, 32.3 years) were randomized to either the NAB (n = 12) or the NEB (n = 9) arm. The baseline characteristics were similar in the two groups. The time-to-first exacerbation was similar in the two groups. At one year, the numbers of patients experiencing exacerbation was significantly lower in the NAB arm (1/12 [8.3%] vs. 6/9 [66.7%]; p = 0.016). The other secondary end points were not different between the two groups. There were no major adverse events leading to discontinuation of any of the study drugs. Three patients experienced bronchospasm after first dose of NAB; however, the subsequent doses were well tolerated.

CONCLUSIONS

NAB seems to be beneficial in decreasing the frequency of exacerbations in patients with ABPA complicating asthma. Larger trials are required to confirm our study results.

Aerosolized amphotericin B as prophylaxis for invasive pulmonary aspergillosis: a meta-analysis

OBJECTIVES

Invasive pulmonary aspergillosis (IPA) is associated with high mortality in high-risk (immunosuppressed) patients. Many studies have investigated whether prophylactic inhalation of amphotericin B (AMB) reduces the incidence of IPA, but no definitive conclusions have been reached. The present meta-analysis was performed to evaluate the efficacy of prophylactic inhalation of AMB for the prevention of IPA.

METHODS

MEDLINE and other databases were searched for relevant articles published until December 2013. Randomized controlled trials that compared aerosolized AMB with placebo were included. Two reviewers independently assessed and extracted the data of all trials.

RESULTS

Six animal studies and two clinical trials involving 768 high-risk patients were eligible. The animal studies showed lower overall mortality rate among animals that underwent aerosolized AMB prophylaxis (odds ratio (OR) 0.13, 95% confidence interval (CI) 0.08-0.21). Similarly, the clinical trials showed a lower incidence of IPA among patients who underwent aerosolized AMB prophylaxis (OR 0.42, 95% CI 0.22-0.79).

CONCLUSIONS

This analysis provides evidence supporting the notion that the prophylactic use of aerosolized AMB effectively reduces the incidence of IPA among high-risk patients.

Liposomes prolong the therapeutic effect of anti-asthmatic medication via pulmonary delivery

Purpose

The main objective of this study was to develop a novel aerosolized liposome formulation for pulmonary delivery of anti-asthmatic medication and to explore the relationship between the bioavailability and anti-asthmatic efficacy of such a formulation. Asthma treatment usually requires frequent administration of medication for sustained bronchodilating response. Liposomes are known for their capability for sustained drug release and thus would be a suitable delivery system for anti-asthmatic medication for prolonged therapeutic effect. Salbutamol sulfate (SBS) was chosen as the model drug in this study because of its high water solubility and fast absorption after administration.

Methods

SBS was efficiently encapsulated into liposomes by the vesicular phospholipid gel technique. SBS permeability across the pulmonary membrane of an Asian toad was determined by in vitro study. Intratracheal administration of liposomes labeled with the fluorescent dye 1,1′-dioctadecyltetramethyl indotricarbocyanine iodide (DiR) in a rat model was assessed by a small animal imaging system and pharmacokinetic analysis. Pharmacodynamic analysis was performed in guinea pigs using the Konzett–Rössler method.

Results

SBS was efficiently encapsulated into liposomes with encapsulation efficiency as high as 70%. The particle size of the SBS liposome suspension was approximately 57 ± 21 nm. In the in vitro study of permeability across the pulmonary membrane of Asian toads, SBS from liposomes demonstrated a slower transport rate compared to free SBS solution. Pulmonary delivery of liposomes in a rat model showed that the liposomes were effectively distributed in the respiratory tract and lungs, and that the release of SBS from liposomes was sustained for at least 48 hours. Pharmacodynamic analysis in a guinea pig model showed that the anti-asthmatic effect of SBS liposomes persisted for up to 18 hours, whereas that of free SBS solution was less than 8 hours.

Conclusion

The overall results demonstrated that liposomes could increase the concentration and retention time of SBS in the lungs and therefore prolong its therapeutic effect.

In vitro characterization of nebulizer delivery of liposomal amphotericin B aerosols

Pharmaceutical aerosols have the potential to prevent pulmonary infectious diseases. Liposomal amphotericin B (LAMB, Ambisome, Astellas Pharma US, Deerfield, IL, USA) is approved as an intravenous infusion for empiric treatment of presumed fungal infections in neutropenic, febrile patients, as well as patients infected with Aspergillus, Cryptococcus, and other fungal pathogens. In this study, four different nebulizers were tested for their ability to deliver LAMB in aerodynamic droplet-size ranges relevant to lung deposition by an inertial sampling technique Mass median aerodynamic diameter (MMAD) and fine particle fraction percent <3.3 μm (FPF(3.3)) and <5.8 μm (FPF(5.8)) were determined by cascade impaction during a 2 min sampling period for each of three trials of all nebulizers. The MMADs for all nebulizers ranged from 1.72 ± 0.11 μm to 2.89 ± 0.12 μm; FPF(3.3) and FPF(5.8) were approximately 80% and 90%, respectively. Although all nebulizers appear acceptable for delivery of LAMB, the Pari LC Star and the Aeroeclipse II were considered the best in terms of delivery of aerosol efficiently and the proportion suitable for lung deposition. Additional research on pulmonary delivery and clinical tolerability is warranted.

A review on the clinical use of inhaled amphotericin B

BACKGROUND

Despite the systemic toxicity of amphotericin B (AMB), it still has a place in treatment or prophylactic regimes of fungal infections.

METHODS

A strategy for minimizing the potential of systemic side effects is to bring it in direct contact with the body site most likely to be infected, such as the administration of AMB as an aerosol. Nebulized amphotericin has been used in humans since 1959. However, due to a lack of sufficient data regarding efficacy, its use is still not established. Little is known about the optimal dose, frequency, duration of administration, and the pharmacokinetics of inhaled AMB in humans.

RESULTS AND CONCLUSIONS

In this review, published data regarding inhaled AMB are summarized, including available descriptions regarding preparation, dose, efficacy, and toxicity, and its place in therapy is discussed. The results from the studies that were reviewed in this article indicate that inhaled AMB may have a place in the prophylactic regimens of patients with prolonged neutropenia and in lung transplant recipients. Furthermore, nebulized (liposomal) AMB may have a place in the treatment of allergic bronchopulmonary aspergillosis (ABPA) in patients with corticosteroid-dependent ABPA.

Antifungal Prophylaxis in Cancer Patients After Chemotherapy or Hematopoietic Stem-Cell Transplantation: Systematic Review and Meta-Analysis

Purpose

To evaluate the effect of antifungal prophylaxis on all-cause mortality as primary outcome, invasive fungal infections (IFIs), and adverse events. Many studies have evaluated the role of antifungal prophylaxis in cancer patients, with inconsistent conclusions.

Methods

We performed a systematic review and meta-analysis of randomized, controlled trials comparing systemic antifungals with placebo, no intervention, or other antifungal agents for prophylaxis in cancer patients after chemotherapy. The Cochrane Library, MEDLINE, conference proceedings, and references were searched. Two reviewers independently appraised the quality of trials and extracted data.

Results

Sixty-four trials met inclusion criteria. Antifungal prophylaxis decreased all-cause mortality significantly at end of follow-up compared with placebo, no treatment, or nonsystemic antifungals (relative risk [RR], 0.84; 95% CI, 0.74 to 0.95). In allogeneic hematopoietic stem-cell transplantation (HSCT) recipients, prophylaxis reduced all-cause mortality (RR, 0.62; 95% CI, 0.45 to 0.85), fungal-related mortality, and documented IFI. In acute leukemia patients, there was a significant reduction in fungal-related mortality and documented IFI, whereas the difference in mortality was only borderline significant (RR, 0.88; 95% CI, 0.74 to 1.06). Prophylaxis with itraconazole suspension reduced documented IFI when compared with fluconazole, with no difference in survival, and at the cost of more adverse events. On the basis of two studies, posaconazole prophylaxis reduced all-cause mortality (RR, 0.74; 95% CI, 0.56 to 0.98), fungal-related mortality, and IFI when compared with fluconazole.

Conclusion

Antifungal prophylaxis decreases all-cause mortality significantly in patients after chemotherapy. Antifungal prophylaxis should be administered to patients undergoing allogeneic HSCT, and should probably be administered to high-risk acute leukemia patients.

Safety of aerosolized amphotericin B

Aerosolized delivery of a number of antimicrobial agents has been studied. Despite a theoretical soundness behind this strategy, full consideration of the potential toxicities associated with this mode of administration is imperative. Aerosolized amphotericin B, as both deoxycholate and lipid formulations, has been studied in a variety of high-risk patient populations for prophylaxis and treatment against fungal infections. Although available data remain inconclusive regarding the clinical efficacy of this therapy, variability among results may be due to lack of standardization of administration methods and doses. Akin to the lack of clinical consensus, data regarding the tolerability of this means of amphotericin B delivery are conflicting. This variability may again be accounted for by the lack of standardized means for aerosolized administration. Owing to uncertain clinical benefit and concern for pulmonary toxicities, the use of aerosolized amphotericin B should be limited to clinical investigations at this time.

Inhaled amphotericin B for prophylaxis against invasive Aspergillus infections

OBJECTIVE

To evaluate the available literature describing the use of inhaled amphotericin B for prophylaxis of invasive Aspergillus spp. infections.

DATA SOURCES

A MEDLINE search was conducted (1966-July 2006) using the key terms amphotericin B, inhaled amphotericin B, Aspergillus spp., invasive aspergillosis, solid-organ transplant, neutropenia, and inhalation. Review of the reference lists of the identified articles was also performed.

STUDY SELECTION AND DATA EXTRACTION

Study selection included published trials, case reports, and case series of humans with hematologic disease and solid-organ transplant who used inhaled amphotericin B in the prevention of invasive Aspergillus infections.

DATA SYNTHESIS

Inhaled amphotericin B has been evaluated for the prevention of invasive aspergillosis (IA) infections in neutropenic patients and certain solid-organ transplant recipients. Use of inhaled amphotericin B seems to reduce the incidence of IA in these patients; however, some of the clinical evidence was limited by factors such as small sample sizes, lack of statistical analyses, and lack of power to detect a difference between prophylaxis and control groups. Although the clinical evidence supporting the use of inhaled amphotericin B has some limitations, its use still may be beneficial for the prophylaxis of invasive Aspergillus infections, especially in solid-organ transplant recipients where the evidence is strongest.

CONCLUSIONS

Invasive Aspergillus infections are becoming more prevalent in high-risk populations (eg, patients with malignancies, following bone marrow transplantation, or following solid-organ transplantation). The mortality rates associated with IA are great in these populations, making prophylaxis an important consideration. Inhaled amphotericin B has recently come into vogue as an option for prophylaxis against IA. Some of the data available supports the use of inhaled amphotericin B for the prevention of IA while providing evidence of fewer drug interactions and toxicities associated with other antifungal agents.

[Fungal infection following reduced-intensity stem cell transplantation (RIST)]

Hematopoietic stem cell transplantation has been established as a curative treatment for advanced hematologic malignancies. Transplantation with a reduced-intensity conditioning regimen has been developed, and the minimal toxicity of reduced-intensity stem cell transplantation (RIST) has made this procedure available for patients of advanced age or with organ dysfunction. The response of malignant lymphoma and some solid tumors to RIST has been observed. RIST with unrelated donors and umbilical cord blood has been studied. Fungal infection is an important complication of RIST. Since the prognosis of fungal infection is poor, the management has been focused on its prophylaxis. Given recent progression in RIST management, the strategy of infectious prophylaxis has also changed. Equipment in the hospital is important for fungal infection; however, the median day of the development of fungal infection is day 100, when most patients are followed as outpatients. The focus of fungal management after RIST is oral antifungal agents rather than in-hospital equipment. Various antifungal agents have recently been developed and applied for clinical use, and many of these have been developed simultaneously for the first time. A major change in antifungal management will probably occur in the next several years.

Pulmonary delivery of insulin by liposomal carriers

Growing attention has been given to the potential of a pulmonary route as a non-invasive administration for systemic delivery of therapeutic agents (mainly peptides and proteins). The lungs provide a large absorptive surface area, extremely thin absorptive mucosal membrane, and good blood supply. The non-invasive nature of this pathway makes it especially valuable for the delivery of large molecular protein. However, pulmonary delivery of peptides and proteins is complicated by the complexity of the anatomic structure of the human respiratory system and the effect of disposition exerted by the respiration process. In this study, novel nebulizer-compatible liposomal carrier for aerosol pulmonary drug delivery of insulin was developed and characterized. Experimental results showed that insulin could be efficiently encapsulated into liposomes by preformed vesicles and detergent dialyzing method. The optimal encapsulation efficiency was achieved when 40% ethanol was used. The particle size of liposomal aerosols from ultrasonic nebulizer approximated to 1 mum. Insulin was stable in the liposomal solution. Animal studies showed that plasma glucose level was effectively reduced when liposomal insulin was delivered by inhalation route of using aerosolized insulin-encapsulated liposomes. Including fluorescent probe (phosphatidylethanolamine-rhodamine) into liposome, we found that the liposomal carriers were effectively and homogeneously distributed in the lung aveolar. Liposome-mediated pulmonary drug delivery promotes an increase in drug retention-time in the lungs, and more importantly, a reduction in extrapulmonary side-effects which invariably results in enhanced therapeutic efficacies.

Aerosolised antibiotics: a critical appraisal of their use

Aerosolised antimicrobial agents have been used in clinical practice since the 1950s. The main advantage of this route of administration is the targeted drug delivery to the site of infection in the lung. Exploitation of this targeted delivery can yield high concentrations at the site of infection/colonisation while minimising systemic toxicities. It is important to note that the ability of a drug to reach the target area in the lung effectively is dependent on a number of variables, including the nebuliser, patient technique, host anatomy and disease-specific factors. The most convincing data to support the use of aerosolised antimicrobials has been generated with tobramycin solution for inhalation (TOBI, Chiron Corp.) for maintenance treatment in patients with cystic fibrosis. In addition to cystic fibrosis, the use of aerosolised antimicrobials has also been studied for the treatment or prevention of a number of additional disease states including non-cystic fibrosis bronchiectasis, ventilator-associated pneumonia and prophylaxis against pulmonary fungal infections. Key studies evaluating the benefits and shortcomings of aerosolised antimicrobial agents in these areas are reviewed. Although the theory behind aerosolised administration of antibiotics seems to be sound, there are limited data available to support the routine use of this modality. Owing to the gaps still existing in our knowledge base regarding the routine use of aerosolised antibiotics, caution should be exercised when attempting to administer antimicrobials via this route in situations falling outside clearly established indications such as the treatment of patients with cystic fibrosis or Pneumocystis pneumonia.

Design of aerosolized amphotericin b formulations for prophylaxis trials among lung transplant recipients

BACKGROUND

Emphasis has been placed on the need for antifungal prophylaxis when transplanted organs are directly exposed to the environment. In lung transplantation, one strategy for prevention has been aerosolization of polyenes into the lung. Despite widespread use of amphotericin B aerosols, there are still few studies on how to validate their effectiveness or optimize pharmacokinetics.

METHODS

We compared results of several of our own studies of lung transplant recipients receiving formulations of amphotericin B with results of other studies.

RESULTS

Recent aerosol studies suggest that aerosols of a lipid formulation of amphotericin B are safe and better tolerated than is amphotericin B deoxycholate. Their use in prophylaxis is associated with very few pulmonary fungal infections.

CONCLUSION

This safe drug delivery at a local body site to directly protect the transplanted organ without systemic antifungal drug exposure is attractive from a cost and toxicity standpoint. However, careful multicenter, comparative studies are still needed to ensure that this strategy is consistently successful.

Antimicrobial prophylaxis in allogeneic bone marrow transplantation. Guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Haematology and Oncology

Patients undergoing allogeneic stem cell transplantation are at high risk for infection with a variety of pathogens during different phases of the procedure. Bacteria and fungi predominate the first phase until engraftment. During the second phase, from engraftment to about day 100, major infectious problems are caused by fungi and cytomegalovirus. Both pathogens remain important under continued immunosuppression, however, in the late post-transplantation period infections with encapsulated bacteria may become a problem. In this review the Infectious Diseases Working Party of the DGHO gives recommendations for prophylaxis of infections under allogeneic stem cell transplantation with drugs and other measures. The aim of the group was to do this on an evidence-based-medicine rating, if possible.

Aspergillus infections in transplant recipients

Aspergillus infections are occurring with an increasing frequency in transplant recipients. Notable changes in the epidemiologic characteristics of this infection have occurred; these include a change in risk factors and later onset of infection. Management of invasive aspergillosis continues to be challenging, and the mortality rate, despite the use of newer antifungal agents, remains unacceptably high. Performing molecular studies to discern new targets for antifungal activity, identifying signaling pathways that may be amenable to immunologic interventions, assessing combination regimens of antifungal agents or combining antifungal agents with modulation of the host defense mechanisms, and devising diagnostic assays that can rapidly and reliably diagnose infections represent areas for future investigations that may lead to further improvement in outcomes.

Comparative safety of amphotericin B lipid complex and amphotericin B deoxycholate as aerosolized antifungal prophylaxis in lung-transplant recipients

BACKGROUND

Aerosolized administrations of amphotericin B deoxycholate (AmBd) and amphotericin B lipid complex (ABLC) in lung transplant recipients were compared for safety and tolerability. The incidence of invasive fungal infections in patients receiving aerosolized amphotericin B formulations as sole prophylaxis was determined.

METHODS

A prospective, randomized (1:1), double-blinded trial was conducted with 100 subjects. AmBd and ABLC were administered postoperatively by nebulizer at doses of 25 mg and 50 mg, respectively, which were doubled in mechanically ventilated patients. The planned treatment was once every day for 4 days, then once per week for 7 weeks. Treatment-related adverse events and invasive fungal infections were quantitated for 2 months after study drug initiation.

RESULTS

Intent-to-treat analysis revealed study drug was discontinued for intolerance in 6 of 49 (12.2%) and 3 of 51 (5.9%) patients in the AmBd- and ABLC-treated groups, respectively (p=0.313). Subjects receiving AmBd were more likely to have experienced an adverse event (odds ratio 2.16, 95% confidence interval 1.10, 4.24, p=0.02). Primary prophylaxis failure within 2 months of study drug initiation was observed in 7 of 49 (14.3%) AmBd-treated patients and 6 of 51 (11.8%) ABLC-treated patients. No fungal pneumonias were observed. Only two (2%) patients experienced documented primary prophylaxis failure with Aspergillus infections within the follow-up period.

CONCLUSIONS

Both aerosol AmBd and ABLC appear to be associated with a low rate of invasive pulmonary fungal infection in the early posttransplant period. Patients receiving ABLC were less likely to experience a treatment-related adverse event.

Effective protection of allogeneic stem cell recipients against Aspergillosis by HEPA air filtration during a period of construction--a prospective survey

High incidence of aspergillosis on transplant units or hematological wards without HEPA air conditioning during periods of demolishing or construction has been reported by several investigators. Here we report monitoring of fungal air contamination during a period of construction on a stem cell transplantation ward using the gravity air-setting plate (GASP) method. Fungal air contamination in HEPA-conditioned patient rooms was constantly low, independent from construction activity. Outside of the patient rooms at the ward's corridor, the fungal load was significantly higher with some peak values. Outside the transplant unit measures of construction led to a significant increase of fungal spore concentration in air. Transplant activity was not reduced during construction and patients were nursed strictly under HEPA conditions. Patients were monitored prospectively for incidence of infections since 1990 and data of patients grafted during construction (n = 28) were compared to those grafted outside building activity (n = 652). An increase of aspergillosis during construction could be clearly excluded. It can be concluded: Nursing of patients undergoing stem cell transplantation in HEPA-conditioned rooms is an effective protection against acquisition of aspergillus-infection, even under environmental conditions with increased air contamination by conidia. The gravity air-setting plate (GASP) method is not expensive and easy to use and allows reliable and quantitative aerobiological spore monitoring.

Risk factors for the development of invasive fungal infections in allogeneic blood and marrow transplant recipients

Blood and marrow transplantation (BMT) is increasingly used to treat malignant and nonmalignant diseases. Despite significant advances in the management of transplant recipients, however, fungal infections remain important life-threatening complications of BMT. Over the past two decades, the incidence of fungal infections in this population has continued to rise. Several factors predispose BMT recipients to invasive fungal infections. These include but are not limited to use of intensive myeloablative chemotherapy and radiation therapy combined with prolonged granulocytopenia; development of acute and chronic graft-versus-host disease; administration of immunosuppressive therapy, particularly using corticosteroids; use of central venous catheters; and prolonged impairment of cell-mediated immunity secondary to the underlying disease and post-transplant immunodeficiency. Environmental factors also play a key part in the pathogenesis of fungal infections. Therefore, infection-control measures are critical to the prevention of such infections. In addition, although Candida and Aspergillus species are still the major culprits, other opportunistic fungi have emerged in recent years.

Amphotericin B in lung transplant recipients

Although the verdict may still be out on the clinical utility of prophylactic administration of amphotericin B, the findings presented by Marra et al. strengthen the argument for its theoretical use by demonstrating that a relatively reproducible range of concentrations can be achieved in the target patient group. Additionally, it was demonstrated that at an inhaled dose of 30 mg, amphotericin B concentrations at the interface of epithelial lining fluid and the lung tissue, the battleground for host invasion, approach therapeutically relevant concentrations. Even though the debate over the utility of aerosolized administration of antimicrobials is far from over, data continue to accumulate that demonstrate the tolerability and describe the characteristics of drug distribution of nebulized amphotericin B. Even with the absence of definitive clinical data, aerosolized administration of amphotericin B may become a viable option for prophylaxis against serious pulmonary fungal infections owing to the severity of disease, lack of serious toxicities associated with this route of administration, and pharmacokinetic and susceptibility data, suggesting a theoretical basis for activity.

Amphotericin B disposition after aerosol inhalation in lung transplant recipients

BACKGROUND

Bronchopulmonary fungal infections continue to be a major cause of morbidity and mortality in lung transplant recipients, and amphotericin B remains the drug of choice for prophylaxis of most fungal infections. Unfortunately, intravenous amphotericin B has numerous serious adverse effects; thus, nebulized amphotericin B could decrease the incidence of adverse effects seen with the intravenous formulation and provide high local concentrations in the lung tissue. We performed a prospective pilot study to characterize the bronchoalveolar lavage (BAL), lung tissue, and plasma concentrations of amphotericin B following inhalation administration to lung transplant recipients.

METHODS

Amphotericin B 30 mg was administered by nebulizer prior to a routine bronchoscopy. Amphotericin B concentrations in BAL samples from the upper and lower lobes, transbronchial biopsies, and plasma (obtained by drawing a blood sample 30 min after the amphotericin B inhalation) were analyzed by HPLC.

RESULTS

Eight patients were enrolled in the study (mean age 50.0 +/- 16.1 y; number of years posttransplant 3.0 +/- 1.9; type of transplant 5 double-lung, 3 single-lung). The mean amphotericin B concentration in the upper and lower lobe BAL samples were 0.68 +/- 0.36 and 0.50 +/- 0.31 microgram/mL, respectively. Amphotericin B concentrations, detected in only 2 of 5 biopsy samples, were 0.118 and 0.03 microgram/g. Amphotericin B was detected in the plasma of only 1 patient (0.19 mg/L).

CONCLUSIONS

This pilot study demonstrated that detectable concentrations of amphotericin B can be attained in both the upper and lower BAL samples following aerosol administration. However, the frequency of the dose and duration of treatment still need to be determined in a larger study.

Spectrum of Aspergillus infection in lung transplant recipients: case series and review of the literature

STUDY OBJECTIVES

(1) To define the incidence and natural history of Aspergillus colonization and infection in lung transplant recipients, and (2) to assess the impact of prophylaxis, surveillance, and therapy on the incidence and outcome of the disease.

DESIGN

Retrospective review of 133 consecutive single or bilateral lung transplantations performed at a single institution, and review of the published literature.

RESULTS

Airway colonization, isolated tracheobronchitis, and invasive pneumonia due to Aspergillus species occurred in 29%, 5%, and 8% of our series, and in 26%, 4%, and 5% of the pooled published data (all series, including ours), respectively. Greater than 50% of all diagnoses were made in the first 6 months after transplantation in both our series and the published literature. Incidence of progression from airway colonization to invasive disease was 1 in 38 in our series and 3 of 97 (3%) in the pooled published data. In patients with isolated tracheobronchitis, all 6 patients in our series and 41 of 50 patients (82%) in all published series, including ours, responded to antifungal therapy and/or surgical debridement. Among patients with invasive pneumonia or disseminated disease, however, 5 of 10 patients in our series and 26 of 64 patients (41%) in the pooled series survived their infection.

CONCLUSIONS

The role of antifungal therapy in Aspergillus airway colonization in lung transplant recipients is unclear. Data support a strategy of scheduled screening bronchoscopy followed by aggressive treatment for isolated Aspergillus tracheobronchitis in lung transplant recipients.

Severe allergic bronchopulmonary aspergillosis in an infant with cystic fibrosis and her asthmatic father

An infant with cystic fibrosis and her asthmatic father were diagnosed as suffering from allergic bronchopulmonary aspergillosis (ABPA). Cystic fibrosis was diagnosed in the infant at 6 weeks of age, and gene mutations were W1282X/G542X. She was diagnosed definitively as suffering from ABPA at age 3.5 years, but had suggestive symptoms from age 11 months. This may be the youngest age described to date for ABPA. The child responded well to systemic steroid therapy, but remained steroid-dependent over the next 4 years. Treatment with itraconazole enabled a marked reduction in steroid dosage. The father was an asthmatic, and a heterozygote for the cystic fibrosis transmembrane regulator (CFTR) mutation W1282X. He had a normal sweat test, atopy, and moderate reversible airway obstruction. There was no proven exposure to Aspergillus in the home environment. The importance of considering the diagnosis of ABPA even in infancy, the therapeutic dilemmas, and the possible role of abnormal CFTR function in the development of ABPA are discussed.

Tc-99m erythromycin lactobionate inhalation scintigraphy in parenchymal lung diseases

We have investigated Technetium 99m erythromycin lactobionate (Tc 99m EL) clearance from the lungs after inhalation, in the presence of an alveolitis. Eighteen patients (6 sarcoidosis, 7 idiopathic fibrosis, and 5 miliary tuberculosis) were imaged after the patients inhaled 1,110 MBq of Tc 99m EL. Clearance half time for the first 45 min, for 24 h, and retention at 24 h correlated with percentage of lymphocytes in bronchoalveolar lavage fluid (BAL) (r = .729, r = .883, and r = .826, respectively). There was a positive correlation between peripheral penetration (PP) and forced expiratory volume in 1 s (FEV1) (r = .806) and forced vital capacity (FVC) (r = .781). Retention was more marked in sarcoidosis compared with tuberculosis (0.025 < p < or = 0.05). Radioaerosol lung imaging may reflect the pulmonary function impairment in parenchymal lung diseases. Retention of Tc 99m EL may be related to number of BAL cells or presence of a lymphocytic alveolitis. Long residency time of Tc 99m EL in the lungs implies that erythromycin can also be administered by inhalation for therapeutic purposes.

Aspergillus fumigatus and aspergillosis

Aspergillus fumigatus is one of the most ubiquitous of the airborne saprophytic fungi. Humans and animals constantly inhale numerous conidia of this fungus. The conidia are normally eliminated in the immunocompetent host by innate immune mechanisms, and aspergilloma and allergic bronchopulmonary aspergillosis, uncommon clinical syndromes, are the only infections observed in such hosts. Thus, A. fumigatus was considered for years to be a weak pathogen. With increases in the number of immunosuppressed patients, however, there has been a dramatic increase in severe and usually fatal invasive aspergillosis, now the most common mold infection worldwide. In this review, the focus is on the biology of A. fumigatus and the diseases it causes. Included are discussions of (i) genomic and molecular characterization of the organism, (ii) clinical and laboratory methods available for the diagnosis of aspergillosis in immunocompetent and immunocompromised hosts, (iii) identification of host and fungal factors that play a role in the establishment of the fungus in vivo, and (iv) problems associated with antifungal therapy.

Accumulation of amphotericin B in human macrophages enhances activity against Aspergillus fumigatus conidia: quantification of conidial kill at the single-cell level

A cytofluorometric assay that allowed assessment of damage to phagocytosed Aspergillus fumigatus conidia at the single-cell level was developed. After ingestion by monocyte-derived macrophages (MDMs), conidia were reisolated by treatment of the cells with streptolysin O, a pore-forming toxin with lytic properties on mammalian cells but not on fungi. The counts obtained by staining of damaged conidia with propidium iodide and quantification by cytofluorometry correlated with colony counts. By the use of this method, we demonstrate that MDMs differentiated in vitro by low-dose granulocyte-macrophage colony-stimulating factor and gamma interferon have only a limited capacity to damage Aspergillus conidia in vitro. The killing rate 12 h after phagocytosis was found to be only 10 to 15%. However, intracellular loading of the phagocytes with amphotericin B (AmB) dose dependently enhanced the anticonidial activity. Preincubation of macrophages with only 1 microg of AmB per ml resulted in an uptake of 18 fg of AmB/cell, leading to killing rates of 50 to 60%. The experimental protocol provides a new tool for the rapid quantification of anticonidial activity against A. fumigatus in vitro. Intracellular accumulation of AmB may represent an important factor underlying the efficacy of this antifungal drug in the prophylaxis and treatment of Aspergillus infections.

Amphotericin B determination in respiratory secretions by reversed-phase liquid chromatography

Direct delivery of amphotericin B (AMB) to the respiratory tract may be an alternative to intravenous administration. The use of inhalation allows high AMB concentrations to be achieved at the site of infection. A reversed-phase high-performance liquid chromatographic method with a 30-mm-long column is described for assaying AMB in respiratory secretions obtained by bronchoaspiration (BAS) and bronchoalveolar lavage (BAL). Sample clean-up involved treatment with methanol (BAS) and solid-phase extraction onto Sep-Pak C18 cartridges (BAL). The mobile phase consisted of 2.5 mM Na2EDTA-acetonitrile (70:30, v/v). The retention time of AMB was 1.5 min. The range of the assay was from 0.1 to 5 micrograms/ml. The mean recovery was over 90% for both fluids. Within-day and between-day RSDs ranged from 3.10 to 11.87%. AMB in the BAS samples was stable for two days at 20-25 degrees C and for three months at -20 degrees C. The drug in the BAL fluid was stable for one day at 20-25 degrees C, seven days at 4 degrees C and for one month at -20 degrees C.

Pharmacokinetic evaluation of amphotericin B in lung tissue: lung lymph distribution after intravenous injection and airspace distribution after aerosolization and inhalation of amphotericin B

We have studied the pharmacokinetics of amphotericin B (AmB) in lung lymph circulation and bronchial-wash fluid after intravenous infusion and inhalation, respectively. For two experiments with awake sheep, we used lung lymph fistulas and tracheotomy. In experiment 1, AmB concentrations in plasma and lung lymph after intravenous infusion of AmB (1 mg/kg of body weight) over 1.5 h were measured. The mean peak in plasma level was 756.0 +/- 188.8 ng/ml at 3 h after the start of infusion, and the level then decreased gradually to 194.8 +/- 28.9 ng/ml at 24 h. The stable and maximal levels in lung lymph last 5 to 9 h after the start of AmB infusion. The concentrations in lung lymph after 9 h were slightly higher than those in plasma. Thus, the lung lymph-to-plasma ratio of AmB concentrations increased gradually during infusion, and the ratio was more than 1.0 after the end of infusion, suggesting that AmB could be easily moved from plasma to pulmonary interstitium and/or lung lymph circulation. In another experiment, 5 or 30 mg of aerosol AmB was inhaled, and the concentration of AmB in the bronchial-wash fluid was determined by bronchoalveolar lavage. The peak AmB concentration in the fluid was observed at 0.5 h. After that, AmB was slowly eliminated over 24 h. The area under the concentration-time curve for 30 mg of inhaled AmB was higher than that for 5 mg, but maximum concentrations of AmB in serum for 5 and 30 mg were almost similar. These observations identify the pharmacokinetic characteristics of AmB in the lung and may provide a new insight into the strategy for clinical treatment of fungal pneumonia.

Successful treatment of rhinocerebral mucormycosis by a combination of aggressive surgical debridement and the use of systemic liposomal amphotericin B and local therapy with nebulized amphotericin--a case report

A case of mucormycosis involving the nose and paranasal sinuses in a 55-year-old man with recently diagnosed acute promyelocytic leukaemia is reported. It was successfully treated with a combination of aggressive surgical debridement and systemic amphotericin B. In addition, local nebulized amphotericin B was used as an adjunct to therapy. We believe this is only the second documented use of nebulized amphotericin in the management of sinonasal mucormycosis. The need for a high index of suspicion and early aggressive management is emphasized.

Invasive aspergillosis in severely neutropenic patients over 18 years: impact of intranasal amphotericin B and HEPA filtration

The impact of intranasal amphotericin B and high-efficiency particulate air (HEPA) filtration on the incidence of invasive aspergillosis was reviewed in patients from 1977 to 1994 undergoing intensive chemotherapy. Overall, the incidence of proven invasive aspergillosis was reduced from 24.4% (1977-1984) to 7.1% (1985-1991) (P < 0.001) following the introduction of intranasal prophylaxis, but when probable cases of aspergillosis were included and lymphoma cases excluded, there was no change in incidence. Following the introduction of HEPA filtration, patient exposure to aspergillus spores as measured by air sampling was markedly reduced and there were no new cases of invasive aspergillosis. HEPA filtration proved effective in reducing invasive aspergillosis and has allowed increasingly aggressive treatment regimens to be introduced.

Disposition of aerosolized liposomal amphotericin B

Amphotericin B (AmB) is an important drug for the treatment of fungal infection, but toxicity limits the lung tissue doses which may be achieved through intravenous administration. Although incorporation of AmB in liposomes reduces these effects and increases the therapeutic index for intravenous administration, targeted delivery to lung tissues via inhaled liposomal AmB aerosol may be a more effective approach. Aerosolization of liposomal amphotericin B targets the lungs, the organs first infested by many fungi. Development of optimal aerosolized liposomal AmB therapies requires a better understanding of the effect that liposome surface charge has on lung clearance kinetics. In this work we evaluated the clearance kinetics and organ distribution of inhaled liposomal AmB in male Balb/C mice. Mice were exposed via nose only to AmB-containing liposomal aerosols having positive, negative, or neutral surface charge characteristics. The formulations were aerosolized using a Collison nebulizer. Groups of animals were euthanized at predetermined times and the lungs and other organs were analyzed for AmB. AmB was not detected in serum and other organs such as kidneys, liver, and brain. The disposition of neutral and positive liposomal amphotericin B in lungs followed biexponential kinetics. The alpha and beta phase half-lives for positive liposomes were 1.3 and 15.1 days, respectively, and 2.3 and 22 days for neutral liposomes. AmB delivered via negative liposomes exhibited monoexponential clearance with a half-life of 4.5 days. These results suggest that toxic side effects in nontarget tissues are minimal and may indicate a potential for long term protection against fungal infections.

Antifungal prophylaxis during neutropenia and immunodeficiency

Fungal infections represent a major source of morbidity and mortality in patients with almost all types of immunodeficiencies. These infections may be nosocomial (aspergillosis) or community acquired (cryptococcosis), or both (candidiasis). Endemic mycoses such as histoplasmosis, coccidioidomycosis, and penicilliosis may infect many immunocompromised hosts in some geographic areas and thereby create major public health problems. With the wide availability of oral azoles, antifungal prophylactic strategies have been extensively developed. However, only a few well-designed studies involving strict criteria have been performed, mostly in patients with hematological malignancies or AIDS. In these situations, the best dose and duration of administration of the antifungal drug often remain to be determined. In high-risk neutropenic or bone marrow transplant patients, fluconazole is effective for the prevention of superficial and/or systemic candidal infections but is not always able to prolong overall survival and potentially selects less susceptible or resistant Candida spp. Primary prophylaxis against aspergillosis remains investigative. At present, no standard general recommendation for primary antifungal prophylaxis can be proposed for AIDS patients or transplant recipients. However, for persistently immunocompromised patients who previously experienced a noncandidal systemic fungal infection, prolonged suppressive antifungal therapy is often indicated to prevent a relapse. Better strategies for controlling immune deficiencies should also help to avoid some potentially life-threatening deep mycoses. When prescribing antifungal prophylaxis, physicians should be aware of the potential emergence of resistant strains, drug-drug interactions, and the cost. Well-designed, randomized, multicenter clinical trials in high-risk immunocompromised hosts are urgently needed to better define how to prevent severe invasive mycoses.

Tolerance and efficacy of Amphotericin B inhalations for prevention of invasive pulmonary aspergillosis in haematological patients

The tolerance of aerosolised amphotericin B as prophylaxis against invasive pulmonary aspergillosis was investigated in 61 granulocytopenic periods in 42 patients treated for a haematologic malignancy. Each patient was to receive amphotericin B in doses escalating to 10 mg three times daily (t.i.d.), but only 20 (48%) patients managed to complete the scheduled regimen. One patient tolerated the full dose initially, but had to discontinue treatment when dyspnea developed as a result of pneumonia and acute respiratory distress. Another 22 patients (52%) experienced side effects, including eight (19%) who reported mild coughing and dyspnea but who tolerated the full dose and three (7%) patients whose dose was reduced to 5 mg t.i.d. Another six (14%) patients could tolerate only 5 mg t.i.d., and five (12%) others stopped treatment because of intolerance. Elderly patients (p < 0.05) and those with a history of chronic pulmonary obstructive disease (p = 0.09) were more likely to develop side effects during inhalation. Twelve (28%) patients developed proven of possible invasive fungal infections, but no correlation was established between infection and the total amount of amphotericin B inhaled. Inhalation of aerosolised amphotericin B is poorly tolerated and does not appear useful in preventing invasive pulmonary aspergillosis in granulocytopenic patients.

Efficacy of prophylactic aerosol amphotericin B lipid complex in a rat model of pulmonary aspergillosis

Invasive pulmonary aspergillosis remains an important cause of morbidity and mortality among transplant recipients and patients receiving cancer chemotherapy. The lipid-associated formulation of amphotericin B (AmB), AmB lipid complex (ABLC), was evaluated for its prophylactic efficacy when it was administered as an aerosol in a rat model of pulmonary aspergillosis. Aerosol ABLC (aero-ABLC), in doses from 0.4 to 1.6 mg/kg of body weight given 2 days before infection, significantly delayed mortality compared to the mortality of rats given placebo (P < 0.001). At day 10 postinfection, 50% of rats in the 0.4-mg/kg group and 75% of rats in the 1.6-mg/kg group were alive, while all control animals had died. In a second trial aero-ABLC was more effective than an equivalent dose of aerosol AmB (aero-AmB) in prolonging survival, with 100% survival at day 14 postinfection in the ABLC group, compared to 62.5% survival in the AmB group. Mean concentrations of AmB in lungs were 3.7 times higher at day 1 (P < 0.002) and almost six times higher at day 7 (P < 0.001) after treatment with aero-ABLC than after treatment with a similar dose of aero-AmB. We conclude that aero-ABLC provided higher and more prolonged levels of the parent compound in the lungs than aero-AmB and was more effective in delaying mortality from aspergillosis in this model.

Aerosol amphotericin B inhalations for prevention of invasive pulmonary aspergillosis in neutropenic cancer patients

To determine the value of aerosol amphotericin B inhalations for prevention of invasive pulmonary aspergillosis (IPA), we initiated a prospective randomized multicenter trial. The scheduled intent-to-treat interim analysis included 115 patients (30%) with prolonged neutropenia after chemotherapy for acute myeloid leukemia, acute lymphoblastic leukemia/high-grade non-Hodgkin's lymphoma, or solid tumors undergoing autologous stem cell transplantation. Sixty-five patients had been randomized to receive prophylactic aerosol amphotericin B inhalations at a dose of 10 mg twice daily (group A); for the remaining 50 patients no aerosol amphotericin B prophylaxis was used (group B). No serious side effects from amphotericin B inhalations occurred, but coughing (54%), bad taste (51%), and nausea (37%) caused early cessation of aerosol amphotericin B prophylaxis in 23% (15/65) of courses. In group A, the incidence of proven, probably, or possible IPA was 5% (3/65) as compared with 12% (6/50) in group B (p > 0.05). Microbiologically documented bacterial pneumonias were observed in 5/65 (8%) patients in group A and in 1/50 (2%) patients in group B (p > 0.05). Thus, no reduction in incidence of IPA from use of prophylactic aerosol amphotericin B inhalations was found in this interim analysis. As there were no serious side effects from aerosol amphotericin B prophylaxis, accrual in the study will continue for a total of 380 patients.

Prevention and therapy of fungal infections in cancer patients. A review of recently published information

This review of recent publications in the field of fungal infections in cancer patients clearly confirms that protracted severe granulocytopenia is a major risk factor for their development. Because severe and prolonged granulocytopenia plays such a major predisposing role for fungal infections, it is likely that the use of the colony-stimulating factors, which are able to reduce the duration and the severity of granulocytopenia, might prove effective in decreasing the frequency and the severity of these infections. Another conclusion is that certain categories of patients with granulocytopenia might benefit from antifungal prophylaxis and empiric therapy. Conversely, there are other populations who will benefit only marginally from such strategies. Imidazoles, namely fluconazole, for the prevention of local and systemic Candida infections have been shown to be effective in granulocytopenic patients. So far, the development of resistance has not been a major problem. In patients at the greatest risk of developing severe fungal infections, such as those receiving high-dose corticosteroid therapy for GVHD after allogeneic bone marrow transplantation, early administration of low doses of amphotericin B seems to be effective in reducing the development of systemic fungal infection. In terms of therapy, amphotericin B is still the standard approach, especially for empiric treatment, prior to the recognition of a specific pathogen.

[Prophylaxis and therapy of fungal infections in oncology]

The observation of a considerable incidence of fungal infections in oncology patients has promoted a large number of studies both on prophylaxis and treatment in this patient group. Trials using triazoles, especially fluconazole, have shown effect in preventing fungal infections. In neutropenic patients, their role in therapy still remains less clear. Amphotericin B is the drug of choice for most life-threatening infections. With this drug, efforts concentrate upon the amelioration of side effects by sodium loading, administration in lipid emulsions or liposomes. The use of AMB as low-dose systemic prophylaxis or by inhalation needs further study.

Use of amphotericin B aerosols for the prevention of pulmonary aspergillosis

Invasive pulmonary Aspergillus infections are increasingly recognized among severely neutropenic and/or immunosuppressed individuals. As the infections are usually acquired through the inhalation of Aspergillus conidia, at present prevention of invasive pulmonary aspergillosis consists mainly of the reduction of environmental exposure to aspergillus conidia. More recently, prophylaxis with amphotericin B aerosols has been investigated. Inhalations with amphotericin B aerosols significantly delayed mortality in an animal model of invasive pulmonary aspergillosis and high pulmonary concentrations of amphotericin B could be achieved. In man, pulmonary deposition of amphotericin B could also be demonstrated using commercially available nebulizers. Inhalations were well tolerated with little systemic absorption of the drug. In order to evaluate the efficacy of aerosol amphotericin B administrations for the prevention of invasive pulmonary aspergillosis, a prospective randomized trial has been initiated.

Low incidence of invasive fungal infections after bone marrow transplantation in patients receiving amphotericin B inhalations during neutropenia

The incidence of invasive fungal infections after bone marrow transplantation (BMT) was analyzed in 303 consecutive marrow graft recipients (allogeneic n = 271, autologous n = 27, syngeneic n = 5). All patients received inhalations with amphotericin B (10 mg twice daily) during neutropenia. The overall incidence of invasive fungal infections within the first 120 days after transplant was 3.6% (11/303; aspergillosis: 6; yeast infection: 5). Four of the 11 cases occurred early, and seven cases were observed after neutrophil recovery and discontinuation of amphotericin B inhalation treatment. Late infection was significantly associated with the development of acute graft-versus-host disease. Four of the 11 infections (early 2/4; late: 2/7) were observed in patients with a history of previous fungal infection. Other patient and treatment characteristics were not helpful in defining potential risk factors. In particular, the incidence of invasive fungal infections did not differ between patients with more or less strict reverse isolation measures. Occasional side effects such as initial mild cough and bad taste were rare, usually disappeared during continued administration, and were in no case the reason for discontinuation of treatment. These data suggest that aerosolized amphotericin B may be a useful, convenient, and efficient prophylactic antifungal regimen in BMT.