Aerosol amphotericin B is effective for prophylaxis and therapy in a rat model of pulmonary aspergillosis

Could the Lung Be a Gateway for Amphotericin B to Attack the Army of Fungi?

Fungal diseases are a significant cause of morbidity and mortality worldwide, primarily affecting immunocompromised patients. Aspergillus, Pneumocystis, and Cryptococcus are opportunistic fungi and may cause severe lung disease. They can develop mechanisms to evade the host immune system and colonize or cause lung disease. Current fungal infection treatments constitute a few classes of antifungal drugs with significant fungi resistance development. Amphotericin B (AmB) has a broad-spectrum antifungal effect with a low incidence of resistance. However, AmB is a highly lipophilic antifungal with low solubility and permeability and is unstable in light, heat, and oxygen. Due to the difficulty of achieving adequate concentrations of AmB in the lung by intravenous administration and seeking to minimize adverse effects, nebulized AmB has been used. The pulmonary pathway has advantages such as its rapid onset of action, low metabolic activity at the site of action, ability to avoid first-pass hepatic metabolism, lower risk of adverse effects, and thin thickness of the alveolar epithelium. This paper presented different strategies for pulmonary AmB delivery, detailing the potential of nanoformulation and hoping to foster research in the field. Our finds indicate that despite an optimistic scenario for the pulmonary formulation of AmB based on the encouraging results discussed here, there is still no product registration on the FDA nor any clinical trial undergoing ClinicalTrial.gov.

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.

Aspergillus fumigatus and aspergillosis: From basics to clinics

The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.

A Critical Review on Emerging Trends in Dry Powder Inhaler Formulation for the Treatment of Pulmonary Aspergillosis

Pulmonary aspergillosis (PA), a pulmonary fungal infection caused by Aspergillus spp., is a concern for immunocompromised populations. Despite substantial research efforts, conventional treatments of PA using antifungal agents are associated with limitations such as excessive systemic exposure, serious side effects and limited availability of the therapeutics in the lungs for an adequate duration. To overcome the limitations associated with the conventional regimens, pulmonary delivery of antifungal agents has become a focal point of research because of the superiority of local and targeted drug delivery. Dry powder inhalers and nebulized formulations of antifungal agents have been developed and evaluated for their capability to effectively deliver antifungal agents to the lungs. Moreover, progress in nanotechnology and the utilization of nanocarriers in the development of pulmonary delivery formulations has allowed further augmentation of treatment capability and efficiency. Thus, the following review provides an insight into the advantages and therapeutic potential of the utilization of nanocarriers in pulmonary delivery of antifungal agents for the treatment of PA. In addition, discussions on formulation aspects and safety concerns together with the clinical and regulatory aspects of the formulations are presented, which suggest the possibility and desirability of utilization of nanocarriers in the treatment of PA.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection: let the virus be its own demise

There has been a collaborative global effort to construct novel therapeutic and prophylactic approaches to SARS-CoV-2 management. Although vaccine development is crucial, acute management of newly infected patients, especially those with severe acute respiratory distress syndrome, is a priority. Herein we describe the rationale and potential of repurposing a dual plasmid, Vigil (pbi-shRNA^furin-GM-CSF), now in Phase III cancer trials, for the treatment of and, in certain circumstances, enhancement of the immune response to SARS-CoV-2.

Animal Models of Aspergillosis

Aspergillosis is an airborne fungal disease caused by Aspergillus spp., a group of ubiquitous molds. This disease causes high morbidity and mortality in both humans and animals. The growing importance of this infection over recent decades has created a need for practical and reproducible models of aspergillosis. The use of laboratory animals provides a platform to understand fungal virulence and pathophysiology, assess diagnostic tools, and evaluate new antifungal drugs. In this review, we describe the fungus, various Aspergillus-related diseases in humans and animals and various experimental animal models. Overall, we highlight the advantages and limitations of the animal models, the experimental variables that can affect the course of the disease and the reproducibility of infection, and the critical need for standardization of the species, immunosuppressive drugs, route of infection, and diagnostic criteria to use.

Nebulised amphotericin B-polymethacrylic acid nanoparticle prophylaxis prevents invasive aspergillosis

Aspergillus species are the major life threatening fungal pathogens in transplant patients. Germination of inhaled fungal spores initiates infection, causes severe pneumonia, and has a mortality of > 50%. This is leading to the consideration of pre-exposure prophylaxis to prevent infection. We made a very low MWt amphotericin B-polymethacrylic acid nanoparticle. It was not toxic to lung epithelial cells or monocyte-derived-macrophages in-vitro, or in an in-vivo transplant immuno-suppression mouse model of life threatening invasive aspergillosis. Three days of nebuliser based prophylaxis delivered the nanoparticle effectively to lung and prevented both fungal growth and lung inflammation. Protection from disease was associated with > 99% killing of the Aspergillus and a 90% reduction in lung TNF-α; the primary driver of tissue destructive immuno-pathology. This study provides in-vivo proof-of-principle that very small and cost-effective nanoparticles can be made simply, and delivered safely and effectively to lung by the aerosol route to prevent fungal infections.

From the Clinical Editor

Aspergillus is an opportunistic pathogen, which affects immunocompromised patients. One novel way to help fight against this infection is pre-exposure prophylaxis. The authors here made PMA based anionic hydrogels carrying amphotericin B, with mucoadhesive behavior. They showed that aerosol route of the drug was very effective in protecting against the disease in an in-vivo model and should provide a stepping-stone towards clinical trials in the future.

The serum glucan level and pathological changes of antifungal treatment for lower respiratory tract infection of Candida albicans

Due to the fact that Candida albicans colonizes in the upper respiratory tracts of healthy people, whether or not its isolation from airway secretions is sufficient to warrant treatment remains controversial. The animal models of immunosuppressive rats with pulmonary candidiasis were established by the intratracheal inoculating suspensions of C. albicans, and the animals were divided into the following three groups: (1) antifungal treatment group, (2) saline control group, and (3) blank control group. We noted the following in our studies: (1) The fungal load of the saline control group gradually increased such that it was higher than those of the antifungal treated group and was significant from the fourth day of treatment (P < 0.01). (2) The serum (1,3)-β-D-glucan (BG) in the saline control group also gradually increased so that it was significantly higher than found with the treated group by the sixth day of treatment (P < 0.05), and in fact, the rank of pulmonary colony count and BG in the two groups at different time points showed an almost perfect linear correlation. (3) The median survival period of the rats in the antifungal treated group and saline control group was 15 and 8 days respectively, no rats died in the blank control group. (4) The lung lesions from the saline control group gradually became more aggravated than those in the antifungal treated group; no significant pathological changes were found in the blank control group. Antifungal treatment (micafungin) is capable of efficaciously decreasing the lung fungal burden, and continuous monitoring of BG is useful for the evaluation of therapeutic effect of antifungals. Infection of C. albicans with associated pathological damage implies the need for antifungal therapy.

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.

Role of nebulized amphotericin B in the management of allergic bronchopulmonary aspergillosis in cystic fibrosis: Case report and review of literature

OBJECTIVES

To review the data available in literature about nebulized amphotericin B (AMB) in the treatment of allergic bronchopulmonary aspergillosis (ABPA) in cystic fibrosis (CF) and to report our experience in the use of this drug, with a particular therapeutic scheme.

CASE REPORT

We used nebulized liposomal amphotericin B (L-AMB) in a patient affected by CF, complicated by ABPA. The previous combined treatment with oral steroids and azoles had no respiratory benefit and caused relevant side effects. Amphotericin B has always been well tolerated and permitted a slight steroid tapering. We also observed benefits in pulmonary function and laboratory tests.

CONCLUSIONS

Few data are available in literature about the use of nebulized AMB in CF and there are no RCTs evaluating antifungals in CF-ABPA. In our opinion, the reported case suggests that nebulized L-AMB could represent a possible strategy in ABPA management in CF patients.

Aerosolized amphotericin B lipid complex as adjunctive treatment for fungal lung infection in patients with cancer-related immunosuppression and recipients of hematopoietic stem cell transplantation

STUDY OBJECTIVE

Aerosolized amphotericin B lipid complex (aeABLC) has been successfully used to prevent fungal disease. Experience with aeABLC as treatment of fungal lung disease is limited.

DESIGN

We evaluated the safety and efficacy of aeABLC adjunct therapy for fungal lung disease in a retrospective study of 32 immunosuppressed adults. All values are given as ± standard deviation.

SETTING

National Cancer Institute-designated Comprehensive Cancer Center.

PATIENTS

Acute leukemia (69%) and severe neutropenia (63%) were common. Fifty-six percent of patients had undergone allogeneic hematopoietic stem cell transplantation 185 ± 424 days prior to aeABLC was commenced.

MEASUREMENT AND MAIN RESULTS

High-dose corticosteroids were administered during aeABLC in 28% of patients. Fungal lung disease was proven or probable in 41% of patients. Most patients (78%) received concurrent systemic antifungal therapy for a median of 14 ± 18 days before aeABLC. The median cumulative aeABLC dose was 1050 ± 2368 mg, and the median duration of aeABLC therapy was 28 ± 130 days. Most patients (78%) received 50 mg aeABLC twice daily. Partial or complete resolution of fungal lung disease was noted in 50% of patients. In three patients (9%) modest cough, mild bronchospasm, and transient chest pain with accompanying nausea and vomiting resolved completely after discontinuation of aeABLC. No patient required hospitalization for drug toxicity or had a serious (grade III or IV) drug-related adverse event.

CONCLUSION

Treatment with aeABLC was tolerated without serious toxicity and may be considered in the setting of severe immunosuppression, cancer, and/or hematopoietic stem cell transplantation in patients with difficult-to-treat fungal lung disease.

Antibacterial efficacy of inhaled squalamine in a rat model of chronic Pseudomonas aeruginosa pneumonia

OBJECTIVES

Squalamine is a steroid extracted from sharks with proven in vitro antibacterial activity. We assessed its efficacy in reducing the lung bacterial load and histological lesions when given via inhalation in a rat model of chronic Pseudomonas aeruginosa pneumonia.

METHODS

Sprague-Dawley rats were inoculated by tracheal intubation with 150 μL of a solution containing 10(8) cfu/mL of agar bead-embedded P. aeruginosa strain PAO1. MICs of squalamine and colistin for this strain were 2-8 and 0.5-1 mg/L, respectively. Starting the day after infection, the animals were treated twice daily with aerosolized squalamine (3 mg), colistin (160 mg) or 0.9% saline for 6 days. The bacterial load and lung histological lesions were evaluated on the seventh day.

RESULTS

Aerosols of squalamine and colistin resulted in a significant reduction in median (IQR) pulmonary bacterial count compared with saline [10(3) (6 × 10(2)-2 × 10(3)), 10(3) (9 × 10(2)-6 × 10(3)) and 10(5) (9 × 10(4)-2 × 10(5)) cfu/lung, respectively; P < 0.001 for both treated groups versus saline]. The lung weight and the lung histological severity score were significantly lower in both treated groups.

CONCLUSIONS

In a model of chronic P. aeruginosa pneumonia, treatment twice daily with a squalamine aerosol for 6 days leads to a significant reduction in the pulmonary bacterial count and pneumonia lesions with an efficacy comparable to that of colistin.

A nebulized intra-tracheal rat model of invasive pulmonary aspergillosis

Animal models are particularly useful for the study of many infectious diseases, including those caused by fungi. Invasive pulmonary aspergillosis is most frequently studied in mouse models. We present here an animal model of this disease based on undernourished immunocompromised rats infected with Aspergillus fumigatus spores by intra-tracheal nebulisation.

Nebulization of four commercially available amphotericin B formulations in persistently granulocytopenic rats with invasive pulmonary aspergillosis: evidence for long-term biological activity

The nebulization of amphotericin B desoxycholate (AMB-DOC), liposomal amphotericin B (L-AMB), amphotericin B lipid complex (ABLC) and amphotericin B colloidal dispersion (ABCD) has been investigated. Particle sizes of generated aerosol droplets were measured. Pulmonary amphotericin B deposition and amphotericin B concentration in blood directly after nebulization and at six weeks after nebulization was measured in healthy rats. The efficacy of nebulized amphotericin B formulations was evaluated in persistently granulocytopenic rats with invasive pulmonary aspergillosis. Treatment was given either after or before fungal inoculation. The endpoint was survival of animals. Aerosol particle sizes, expressed as the values for the mass median diameter were 1.38, 2.43, 0.90 and 2.29 μm for AMB-DOC, L-AMB, ABLC and ABCD, respectively. Amphotericin B concentrations in the lungs directly after nebulization exceeded the minimum inhibitory concentration of Aspergillus fumigatus and amphotericin B was still detected in lungs of rats at six weeks after nebulization. Treatment, started at 16 h after fungal inoculation, resulted in a significantly prolonged survival as compared with sham-treated rats for all four formulations. Prophylactic treatment at one week before fungal inoculation resulted in a significantly prolonged survival for all four formulations. Aerosol treatment given at two weeks before inoculation was effective only for AMB-DOC and L-AMB, whereas treatment given at six weeks resulted in a significantly prolonged survival for L-AMB only. All commercially available amphotericin B preparations could be nebulized efficiently and may be of value in the prophylactic treatment of invasive pulmonary aspergillosis.

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.

Inhaled therapeutics for prevention and treatment of pneumonia

The lungs are the most common site of serious infection owing to their large surface area exposed to the external environment and minimum barrier defense. However, this architecture makes the lungs readily available for topical therapy. Therapeutic aerosols include those directed towards improving mucociliary clearance of pathogens, stimulation of innate resistance to microbial infection, cytokine stimulation of immune function and delivery of antibiotics. In our opinion inhaled antimicrobials are underused, especially in patients with difficult-to-treat lung infections. The use of inhaled antimicrobial therapy has become an important part of the treatment of airway infection with Pseudomonas aeruginosa in cystic fibrosis and the prevention of invasive fungal infection in patients undergoing heart and lung transplantation. Cytokine inhaled therapy has also been explored in the treatment of neoplastic and infectious disease. The choice of pulmonary drug delivery systems remains critical as air-jet and ultrasonic nebulizer may deliver sub-optimum drug concentration if not used properly. In future development of this field, we recommend an emphasis on the study of the use of aerosolized hypertonic saline solution to reduce pathogen burden in the airways of subjects infected with microbes of low virulence, stimulation of innate resistance to prevent pneumonia in immunocompromised subjects using cytokines or synthetic pathogen-associated molecular pattern analogues and more opportunities for the use of inhaled antimicrobials. These therapeutics are still in their infancy but show great promise.

Dose tolerability of chronically inhaled voriconazole solution in rodents

Invasive pulmonary aspergillosis (IPA) is a fungal disease of the lung associated with high mortality rates in immunosuppressed patients despite treatment. Targeted drug delivery of aqueous voriconazole solutions has been shown in previous studies to produce high tissue and plasma drug concentrations as well as improved survival in a murine model of IPA. In the present study, rats were exposed to 20 min nebulizations of normal saline (control group) or aerosolized aqueous solutions of voriconazole at 15.625 mg (low dose group) or 31.25mg (high dose group). Peak voriconazole concentrations in rat lung tissue and plasma after 3 days of twice daily dosing in the high dose group were 0.85+/-0.63 microg/g wet lung weight and 0.58+/-0.30 microg/mL, with low dose group lung and plasma concentrations of 0.38+/-0.01 microg/g wet lung weight and 0.09+/-0.06 microg/mL, respectively. Trough plasma concentrations were low but demonstrated some drug accumulation over 21 days of inhaled voriconazole administered twice daily. Following multiple inhaled doses, statistically significant but clinically irrelevant abnormalities in laboratory values were observed. Histopathology also revealed an increase in the number of alveolar macrophages but without inflammation or ulceration of the airway, interstitial changes, or edema. Inhaled voriconazole was well tolerated in a rat model of drug inhalation.

The utility of a nebulised intra-tracheal rat model of invasive pulmonary aspergillosis

Invasive pulmonary aspergillosis (IPA) is of particular concern to immunodeficient patients, whose mortality rates may exceed 80%. The development of an animal model that faithfully reproduces the pathophysiology of IPA would improve the studies on diagnostic and therapeutic modes, and the use of rats as a possible model for IPA seems to have been largely overlooked. Such a model could be established with the MicroSprayer IA-1B. Male Sprague-Dawley rats (6-8 weeks old) were rendered immunodeficient by cyclophosphamide injections and a protein-deficient diet. On day D0, they were anaesthetised by inhalation of 5% isoflurane and infected by the intra-tracheal aerosolization of 100 microl of an Aspergillus fumigatus spore suspension through a MicroSprayer IA-1B. This inoculation process was simple and rapid, with no deaths observed during or immediately after the procedure. The rats regained consciousness within 1 min. Follow-up data including those for clinical factors (weight changes, mortality rate), biological factors (Aspergillus antigens) and histological factors were consistent with previous studies. The advantages of this model include the ease of animal manipulation, the reproducibility of infection and the potential for repeated blood sampling.

Meta-analysis of nebulized amphotericin B to prevent or treat pulmonary aspergillosis in immunosuppressed animals

OBJECTIVES

Pulmonary aspergillosis in immunosuppressed patients is associated with significant mortality and morbidity. We assessed the prophylactic and therapeutic effect of nebulized amphotericin B (AmB) on mortality of immunosuppressed animals with pulmonary aspergillosis in this meta-analysis.

METHODS

Literature search was based on MEDLINE (1966 to January 15, 2007), EMBASE, and Cochrane-Controlled Trials Register (2006 issue 4) databases. Only randomized-controlled studies comparing nebulized AmB with placebo on immunosuppressed animals were included. Two reviewers reviewed and extracted the data independently.

RESULTS

Eight studies including 839 immunosuppressed animals were considered. The overall mortality of the immunosuppressed animals with pulmonary aspergillosis treated with nebulized AmB was reduced (69.4% versus 87.7%, odds ratio [OR] 0.12, 95% confidence interval [CI]: 0.08-0.19; P < 0.0001). The effect of nebulized AmB on mortality was more significant when the drug was administered as prophylaxis before the inoculation of Aspergillus fumigatus (OR 0.07, 95% CI: 0.03-0.12, P = 0.0001; I(2) = 0) than as a therapeutic agent (OR 0.20, 95% CI: 0.11-0.36, P < 0.0001; I(2) = 0) (ratio of the 2 ORs = 2.86, 95% CI: 1.03-6.11; P = 0.04). The effectiveness of AmB desoxycholate (OR 0.16, 0.06-0.38, P < 0.0001; I(2) = 0) and lipid-associated (liposomal, or lipid complex or colloidal dispersion) amphotericin (OR 0.11, 95% CI: 0.06-0.20, P < 0.0001; I(2) = 0) was not significantly different (ratio of the 2 ORs = 1.46, 95% CI: 0.49-4.39; P = 0.50). Three studies evaluated the potential side effects of nebulized amphotericin and showed that there was no significant renal toxicity but the amphotericin desoxycholate had some detrimental effects on pulmonary surfactant function.

CONCLUSIONS

The use of nebulized amphotericin, either as a prophylactic or therapeutic agent, is effective in reducing mortality of immunosuppressed animals with pulmonary aspergillosis. A large randomized controlled trial is needed to confirm whether combining nebulized amphotericin with systemic antifungal agents will reduce mortality in immunosuppressed patients with suspected or proven pulmonary aspergillosis.

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.

Unlabeled uses of nebulized medications

PURPOSE

The uses, dosing recommendations, benefits, and disadvantages of unlabeled drugs administered by nebulization are reviewed.

SUMMARY

Nebulization is gaining popularity as a treatment alternative, and many drugs are used unlabeled in a nebulized form, including the opioids, lidocaine, magnesium sulfate, amphotericin B, and colistin. The opioids are frequently used to treat dyspnea in end-stage diseases. Common dosages include 1-2 mg every two hours as needed for hydromorphone and 25-50 microg every two hours for fentanyl citrate. Lidocaine can be used to relieve bronchoconstriction and cough symptoms as well as acting as a local anesthetic. It is typically given in a dose between 20 and 160 mg. Nebulized magnesium sulfate can be used in managing acute asthma and is given in dosages between 125 and 250 mg every 20 minutes, with no more than four consecutive doses. Nebulized amphotericin B can be used to prevent infections in immunocompromised patients. A typical amphotericin B regimen is 25 mg every 24 hours. Nebulized colistin is being studied in the prevention and treatment of gram-negative infections and in patients awaiting lung transplants. Colistin is often given as 75 mg every 12 hours to combat infections.

CONCLUSION

Unlabeled nebulization of opioids, lidocaine, magnesium, amphotericin B, and colistin is an alternative method of treatment for patients with pulmonary problems or infections or for those undergoing bronchoscopy. More research is needed to develop guidelines for their use since nebulization may provide benefits to many patients who otherwise cannot be treated or would be at risk of systemic adverse effects of the drugs.

Non-comparative evaluation of the safety of aerosolized amphotericin B lipid complex in patients undergoing allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplant (HSCT) recipients are at increased risk for invasive fungal infections (IFIs) over prolonged periods of time. Aerosolized amphotericin B lipid complex (ABLC) has shown promise in lung transplant recipients as a convenient means of delivering protective drug to the upper airways avoiding systemic toxicities. The safety and tolerability of aerosolized ABLC in 40 subjects undergoing allogeneic HSCT was prospectively investigated in an open-labeled, non-comparative study. Subjects received aerosolized ABLC treatment once daily for 4 days, then once weekly for 13 weeks; fluconazole was administered daily as standard of care through post-transplant day 100. Pulmonary mechanics were measured before and after each dose of inhaled ABLC; adverse events (AEs) and the development of IFI were also monitored. Cough, nausea, taste disturbance, or vomiting followed 2.2% of 458 total inhaled ABLC administrations; 5.2% of inhaled ABLC administrations were associated with >or=20% decrease in pulmonary function measurements (forced expiratory volume in 1 second or forced vital capacity) and none required treatment with bronchodilators or withdrawal from study. Four mild AEs were considered possibly or probably related to study treatment; no deaths or withdrawals from treatment were attributed to study drug. Of 3 proven IFIs occurring during the study period, only 1, a catheter-related case of disseminated fusariosis, occurred while the subject was receiving study medication. Aerosolized ABLC was well tolerated in allogeneic HSCT recipients. With only 1 of 40 subjects developing IFI while receiving treatment, the combination of fluconazole and inhaled ABLC warrants further study as antifungal prophylaxis following allogeneic HSCT.

The use of topical nonabsorbable gastrointestinal antifungal prophylaxis to prevent fungal infections in critically ill immunocompetent patients: A meta-analysis

OBJECTIVE

To investigate the preventive effect of topical nonabsorbable gastrointestinal antifungal prophylaxis on the incidence of fungal infection in critically ill immunocompetent patients.

DATA SOURCE

Randomized controlled studies involving critically ill pediatric and adult patients in different languages from the Cochrane Controlled Trial Register (2004, issue 1), EMBASE, and MEDLINE databases (1966 to 30 April 2004) were included. Studies evaluating absorbable antifungal prophylaxis were excluded. Two reviewers assessed the quality of the studies and performed data extraction independently.

DATA

Amphotericin B and nystatin were used as the nonabsorbable antifungal prophylaxis in the 15 studies included in this meta-analysis. Ten studies used a concomitant systemic antibiotic and four more studies used concomitant topical nonabsorbable antibiotics in the treatment group. Only one study compared topical nonabsorbable antifungal prophylaxis alone with placebo. The total incidence of fungal infections (relative risk [RR], 0.30; 95% confidence interval [CI], 0.18-0.48; p < .00001; extent of inconsistency [I(2)] = 0%) and proportion of patients with fungal infection (RR, 0.50; 95% CI, 0.28-0.87; p = .02; I(2) = 0%) were significantly reduced with topical nonabsorbable antifungal prophylaxis. The incidence of fungal urinary tract infection was significantly reduced (RR, 0.27; 95% CI, 0.10-0.74; p = .01; I(2)= 0%) but not fungal pneumonia (RR, 0.57; 95% CI, 0.28-1.16; p = .12; I(2)= 0%). Fungemia and catheter-related fungal sepsis were rare and not significantly reduced with nonabsorbable antifungal prophylaxis. The results remained unchanged in the sensitivity analyses after exclusion of studies with unclear study quality or exclusion of the contribution of fungal urinary tract infections to the total incidence of fungal infections.

CONCLUSIONS

In critically ill immunocompetent patients who are at high risk of fungal infection, topical nonabsorbable gastrointestinal antifungal prophylaxis was associated with a reduced incidence of urinary fungal infections and a trend toward reduction in respiratory fungal infections and fungemia. Limitations in study data are such that many of these infections may have represented superficial infections of uncertain clinical importance; a large, randomized, controlled trial is needed to assess the cost-effectiveness and safety of topical nonabsorbable antifungal prophylaxis in critically ill patients.

Efficacy of nebulized liposomal amphotericin B in treatment of experimental pulmonary aspergillosis

The efficacy of therapeutic aerosolized amphotericin B (AMB) was studied in a steroid-immunosuppressed murine model of invasive pulmonary aspergillosis. Nebulized liposomal AMB can be a valid approach to the treatment of this infection, with subjects showing significantly improved survival relative to that of subjects given intravenous deoxycholate AMB, as well as lower lung weights and pulmonary glucosamine levels.

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.

New and emerging antifungal agents: impact on respiratory infections

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

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.

Disseminated aspergillosis due to Aspergillus flavus in an experimental model: efficacy of azole therapy

The aim of this investigation was to create a reproducible experimental model of disseminated Aspergillus flavus aspergillosis, and to compare the relative therapeutic efficacies of itraconazole and fluconazole in this model. Temporarily immunosuppressed male Wistar rats received intravenous challenge by A. flavus conidia. Treatment was initiated 24 h later with oral itraconazole (1 mg kg-1 BW day-1), oral fluconazole (1 mg kg-1 BW day-1) or excipient only (infected-untreated rats); this was continued for 10 days. At this time, although 100% mortality had occurred among all infected-untreated rats, no mortality was noted among the control-uninfected, infected-itraconazole-treated or infected-fluconazole-treated rats. After killing, essential organs were processed for microbiological and histopathological studies. Aspergillus flavus was recovered in high colony counts from the organs of infected-untreated rats (lungs > liver > brain > kidneys), but in significantly lower colony counts, or not at all, from the organs of itraconazole-treated and fluconazole-treated rats. Histopathological alterations were pronounced in tissues of infected-untreated rats, but less so in treated rats. These data suggest that administration of itraconazole or fluconazole sufficiently early may prevent, or retard, progression of lesions in disseminated aspergillosis.

Nebulized amphotericin B prophylaxis for Aspergillus infection in lung transplantation: study of risk factors

BACKGROUND

Aspergillus infection remains a major cause of morbidity and mortality after lung transplantation. Therefore, some strategies have been attempted, one of which is nebulized amphotericin B (nAB); however, the efficacy of this prophylaxis has not been shown clearly. The aim is to study whether nAB can protect against Aspergillus infection in lung transplant recipients.

PATIENTS AND METHODS

A study of risk factors was conducted in 55 consecutive lung allograft recipients. Twenty-three potential risk factors were analyzed. In 44 (80%) patients, nAB was indicated as prophylaxis. Multivariate analysis using logistic regression was performed.

RESULTS

Eighteen of the 55 patients (33%) developed infection due to Aspergillus spp. Multivariate analysis showed nAB to be a preventive factor (odds ratio: 0.13; 95% confidence interval [CI] 0.02-0.69; p < 0.05) and cytomegalovirus (CMV) disease was an independent risk factor for developing Aspergillus infection (odds ratio: 5.1; 95% CI 1.35-19.17; p < 0.05). Only 1 patient required withdrawal of the prophylaxis owing to bronchospasm. nAB was well-tolerated in the remaining patients with only a few, mild, easily controlled side effects.

CONCLUSIONS

The present results show that nAB prophylaxis may be efficient and safe in preventing Aspergillus infection in lung-transplanted patients, and CMV disease increases the probability of Aspergillus infection.

Aspergillosis in bone marrow transplant recipients

Invasive aspergillosis in bone marrow transplant recipient is associated with a high mortality. Diagnosis is often delayed because the inflammatory response is blunted by immunosuppression. The gold standard of tissue biopsy is often considered too in invasive as the procedure is often complicated by bleeding and secondary infection. Recent finding on non-invasive tests such as serial measurement of peripheral blood galactomannan antigen or DNA appears to be promising. However, the limited availability of such tests and requirement for expertise are still hampering their use in routine clinical management. More often than not, initiation of antifungal therapy is empirical and based on suggestive radiological changes. Amphotericin B remains the gold standard of therapy but liposconal preparation may prove to be less nephrotoxic and equally effective. Treatment outcome depends more on the acceleration of the recovery of the immune system and the reduction of anti-GVHD therapy than the antifungal agent followed by surgical resection. The efficacy of many reported anti-aspergillosis prophylactic regimen has not been proved in randomized control trials. Despite the absence of data, such policy should still be considered in transplant units with high incidence of aspergillus or undergoing renovation.

Prevention and prophylaxis of invasive fungal sinusitis in the immunocompromised patient

Fungal infections are a leading cause of morbidity and mortality among immunocompromised patients. Invasive fungal sinusitis is a devastating complication of immunosuppression. Treatment options are limited and often ineffective, making prevention important. Measures to decrease environmental exposure, indications for antifungal prophylaxis, and limitations of current regimens are discussed.

Fungal pneumonia in a captive black rhinoceros

A captive black rhinoceros (Diceros bicornis) with a hoof abscess was treated with long-term antibiotic therapy. After 9 months of treatment, there was rapid deterioration, marked weight loss and reluctance to stand. Profuse, bilateral epistaxis developed accompanied by collapse and the animal was euthanased. Necropsy revealed pulmonary aspergillosis with concurrent Pseudomonas aeruginosa infection. Though a well-recognized disease of black rhinoceros, fungal pneumonia has not been reported in this species in Australia. The cost and efficacy of treatment have been questioned, however, prophylactic antifungal drug administration will be considered in any further cases of chronic, debilitating illness in black rhinoceros at Western Plains Zoo.

Aerosolised liposomal hamycin for treatment of systemic Candida infections in mice

Mice lethally infected with Candida albicans were exposed to small-particle aerosols containing hamycin liposomes. The drug, when administered twice daily for 2 h (0.68 mg kg(-1) body weight per day) on days 1, 2 and 3 post inoculation, significantly reduced the numbers of Candida organisms in the kidneys. Aerosol treatment increased the survival time of mice given two 2-h treatments once a week for 4 weeks. A twice weekly 2-h small particle aerosol administration of hamycin for 1, 2, or 3 weeks significantly increased both the mean time of survival and percent survival.

Efficacy of NND-502, a novel imidazole antimycotic agent, in experimental models of Candida albicans and Aspergillus fumigatus infections

In vitro and in vivo anti-Candida albicans and anti-Aspergillus fumigatus activities of NND-502, a new imidazole-antimycotic, were compared with those of fluconazole (FCZ), itraconazole (ITZ) and/or amphotericin B (AmB). NND-502 exhibited strong in vitro antifungal activity against both fungal species; its MIC against C. albicans was 1-4 times lower than that of FCZ, and its MIC against A. fumigatus was at least 60-2000 times lower than that of ITZ and AmB. In vivo antifungal treatments with each drug were initiated 1 h after inoculation in the experimental models, so that antifungal potential reflected prophylactic activity rather than therapeutic activity. The oral regimen of NND-502 in a murine model of systemic C. albicans infection was much less effective than that of FCZ. In vivo anti-A. fumigatus activity of oral NND-502 in a murine model of systemic infection was apparently superior to that of FCZ and ITZ in terms of prolonging survival. In addition to the murine model of systemic aspergillosis, intravenous NND-502 was shown to be highly effective in a rat model of pulmonary aspergillosis compared with intravenous AmB; 90% of animals survived at a dose of 2.5 mg/kg per day of NND-502 while only 30% of animals escaped death when 5 mg/kg per day of AmB was used. This potent efficacy of NND-502 was also confirmed in a sublethal challenge study in which the administration of the agent at a dose as low as 1.25 mg/kg per day resulted in the significant reduction of organisms in the lung; no comparable effect of AmB was found.

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.

Activity of voriconazole (UK-109,496) against clinical isolates of Aspergillus species and its effectiveness in an experimental model of invasive pulmonary aspergillosis

Voriconazole, a new azole antifungal agent, showed potent activity against clinical isolates of Aspergillus spp. in vitro. For A. fumigatus, the MIC range was < 0.03 to 0.5 microgram/ml and the MIC at which 90% of isolates are inhibited was 0.25 microgram/ml. In an experimental model of invasive pulmonary aspergillosis which mimics infection in humans, oral voriconazole at dosages of 30 mg/kg of body weight per day significantly delayed or prevented mortality.

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.

Carrier effects on biological activity of amphotericin B

Amphotericin B (AmB), the drug of choice for the treatment of most systemic fungal infections, is marketed under the trademark Fungizone, as an AmB-deoxycholate complex suitable for intravenous administration. The association between AmB and deoxycholate is relatively weak; therefore, dissociation occurs in the blood. The drug itself interacts with both mammalian and fungal cell membranes to damage cells, but the greater susceptibility of fungal cells to its effects forms the basis for its clinical usefulness. The ability of the drug to form stable complexes with lipids has allowed the development of new formulations of AmB based on this property. Several lipid-based formulations of the drug which are more selective in damaging fungal or parasitic cells than mammalian cells and some of which also have a better therapeutic index than Fungizone have been developed. In vitro investigations have led to the conclusion that the increase in selectivity observed is due to the selective transfer of AmB from lipid complexes to fungal cells or to the higher thermodynamic stability of lipid formulations. Association with lipids modulates AmB binding to lipoproteins in vivo, thus influencing tissue distribution and toxicity. For example, lipid complexes of AmB can be internalized by macrophages, and the macrophages then serve as a reservoir for the drug. Furthermore, stable AmB-lipid complexes are much less toxic to the host than Fungizone and can therefore be administered in higher doses. Experimentally, the efficacy of AmB-lipid formulations compared with Fungizone depends on the animal model used. Improved therapeutic indices for AmB-lipid formations have been demonstrated in clinical trials, but the definitive trials leading to the selection of an optimal formulation and therapeutic regimen have not been done.

Characterization of amphotericin B aerosols for inhalation treatment of pulmonary aspergillosis

In recent years, the incidence of invasive pulmonary aspergillosis has increased in patients receiving immunosuppressive therapy and/or organ transplantation. For prophylaxis against Aspergillus infections, amphotericin B may be a useful drug when inhaled as aerosol. In this study, the aerosolization of amphotericin B was investigated using eight different medical nebulizers under various operating conditions and with different amphotericin B concentrations in the solution. The output of each nebulizer was characterized by the mass flow of spray (drug) leaving the mouthpiece and by the size distribution of the droplets. An effective prevention of pulmonary aspergillosis via amphotericin B inhalation requires a high pulmonary deposition of the drug within an acceptable time of administration associated with a low deposition in the oropharyngeal region. To evaluate the dosages of drug delivered by various types of nebulizers to different regions of the respiratory tract, a semi-empirical deposition model was applied which is based on experimental aerosol deposition data from over 20 normal adults. The main results of the study are: Solutions with amphotericin B concentrations up to 10 mg/ml can be converted into sprays by means of medical nebulizers without any problems. For most nebulizers, the slight foaming of the amphotericin B solution has no effect on the production of the aerosol. To optimize amphotericin B treatment of the lungs via inhalation, sprays with mass flows above 100 mg/min and with mass median aerodynamic diameters (MMAD) below 3 microns should be slowly inhaled by the subject. Applying these criteria to the nebulizers investigated, three out of eight devices have proved suitable for amphotericin B treatment via inhalation.

Fungal infections in lung and heart-lung transplant recipients. Report of 9 cases and review of the literature

We reviewed the pattern and incidence of fungal infections in patients undergoing lung and heart-lung transplantation at Duke University Medical Center from September 1992 until August 1995, and present here 9 illustrative cases. Of the 73 lung and heart-lung transplant recipients studied, 59 (81%) had positive fungal cultures at some point after transplantation. The cases presented here illustrate that lung transplant recipients are predisposed to a wide variety of fungal infections. The clinical pattern of these infections ranges from asymptomatic to rapidly progressive fatal disease. In addition to the reactivation of previous fungal infections and recent exposure to new environmental sources, the donor lung itself can be the source of fungal infection, as we showed by using molecular epidemiology techniques. Because of the associated morbidity and mortality, efforts should be directed at investigating prophylactic antifungal regimens in lung transplant recipients. Preliminary reports on the use of itraconazole and aerosolized amphotericin B have been encouraging. Prospective randomized studies are needed to assess the safety and cost effectiveness of different regimens. Fungal infections in patients after lung transplantation can significantly impede recovery and lead to substantial mortality.

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.

The physiologic effects of inhaled amphotericin B

Our institution used an experimental protocol for the use of inhaled amphotericin B as a prophylactic measure to prevent fungal disease in severely immunocompromised patients. We did a prospective study of the physiologic effects of amphotericin B administration. We looked specifically at oxygen saturation levels, peak flow values, and symptoms of patients given amphotericin B. We collected data on a series of 18 patients and of 132 amphotericin B administrations. Four (22%) of the patients stopped treatments because of nausea and vomiting which were believed to be due to the inhaled amphotericin B. For the remaining patients, no treatment was stopped because of symptoms or physiologic changes caused by amphotericin B, although there were 9 instances of clinically significant bronchospasm as defined by a drop in peak flow of 20% or more, 9 clinically relevant increases in cough, and 3 clinically relevant increases in dyspnea. Forty-eight percent of the clinically relevant changes occurred in patient 8. Another 16% occurred in asthmatic subjects who were significantly more likely (p = 0.03) to experience a 20% or more drop in peak flow than were patients without asthma. The physiologic profile of the response to inhaled amphotericin B is acceptable.

Aerosol and parenteral pneumocandins are effective in a rat model of pulmonary aspergillosis

The pneumocandins are semisynthetic analogs of echinocandin-like compounds that have shown efficacy in animal models of systemic candidiasis, disseminated aspergillosis, and pneumocystis pneumonia. However, the most common form of Aspergillus infection in susceptible patients is pulmonary aspergillosis, which was not directly tested in the mouse models used in the past. We have evaluated three pneumocandins, L-693,989, L-731,373, and L-733,560, in a rat model of pulmonary aspergillosis. Male Sprague-Dawley rats were treated for 2 weeks with cortisone and tetracycline and fed a low-protein diet before being inoculated via the trachea with 10(6) conidia of Aspergillus fumigatus H11-20. In the absence of drug treatment, the animals developed a progressive, rapidly fatal bronchopneumonia. All three pneumocandins at doses of 5 mg/kg (intraperitoneally [i.p.] every 12 h [q12h]) were effective in delaying mortality in this model. Survival at day 7 postinfection was 20% among controls (n = 10 for all groups), while it was 60, 80, and 90% in groups that were treated with L-693,989, L-731,373, and L-733,560, respectively. In another trial, survival at day 7 postinfection was 25% among controls (n = 8 for all groups); it was 87.5% in a group treated with amphotericin B (0.5 mg/kg i.p. q12h) and was 100% in a group treated with L-733,560 (0.625 mg/kg i.p. q12h). In a separate trial, aerosol L-693,989 administered 2 h before infection (5 mg/kg) delayed mortality. Eight of the 10 animals treated with aerosol L-693,989 survived for 7 days, whereas only 2 of 10 control animals survived. We conclude that the pneumocandins we tested were highly effective in an animal model of pulmonary aspergillosis.