Nebulized amphotericin B concentration and distribution in the respiratory tract of lung-transplanted patients

Treatment of pulmonary mucormycosis with adjunctive nebulized amphotericin B (MUCONAB trial): Results of an open-label randomized controlled trial

BACKGROUND

The role of nebulized amphotericin B (NAB) in managing pulmonary mucormycosis (PM) is unknown.

METHODS

In this open-label trial, we randomized PM subjects to receive either intravenous liposomal amphotericin B (control arm, 3-5 mg/kg/day) alone or along with nebulized amphotericin B deoxycholate (NAB, 10 mg twice a day, every alternate day). The primary outcomes were: (1) overall response ('success' [complete or partial response] or 'failure' [stable disease, progressive disease, or death]) at 6 weeks; and (2) the proportion of subjects with adverse events (AE). The key secondary outcome was 90-day mortality. We performed a modified intention-to-treat (mITT) analysis where we included only subjects receiving at least a single dose of NAB.

RESULTS

Fifteen and 17 subjects were randomized to the control and NAB arms; two died before the first dose of NAB. Finally, we included 30 subjects (15 in each arm; mean age 49.8 years; 80% men) for the mITT analysis. Diabetes mellitus (n = 27; 16/27 were COVID-19-associated PM) was the most common predisposing factor. The overall treatment success was not significantly different between the control and the NAB arms (71.4% vs. 53.3%; p = .45). Twenty-nine subjects experienced any AE, but none discontinued treatment. The 90-day mortality was not significantly different between the control (28.6%) and NAB arm (53.3%; p = .26).

CONCLUSION

Adjunctive NAB was safe but did not improve overall response at 6 weeks. A different dosing schedule or nebulized liposomal amphotericin B may still need evaluation. More research is needed to explore other treatment options for PM.

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.

Preclinical Studies of the Nebulized Delivery of Liposomal Amphotericin B

Background: Intravenous liposomal amphotericin B (L-AMB) has accompanying side effects that may be diminished when administering an inhaled form. Delivery systems for inhaled or aerosolized L-AMB vary, and there has not been a recent comparison of available systems to date. Methods: We compared three differently designed nebulizer delivery systems for the inhaled delivery of L-AMB to determine the best combination of efficient lung dosing and treatment time. Aerosol size was measured using a Malvern Mastersizer, and five separate nebulizers were tested. For drug output measurements, a Harvard Lung was used, and aerosol was collected using HEPA filters. Results: Overall aerosol size characteristics were similar for all devices with volume median diameters in the 4-5 μm range. The highest inhaled dose was delivered by the AeroEclipse. The Aerogen and the AeroEclipse had similar predicted pulmonary doses, and the AeroEclipse had the highest pulmonary delivery rates. Conclusion: The AeroEclipse nebulizer may provide more efficient delivery in a shorter amount of time; however, human studies are warranted to assess the safety, tolerability, and efficacy of inhaled delivery of L-AMB from this system.

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.).

Invasive Aspergillosis in solid-organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated AST-IDCOP guidelines provide information on epidemiology, diagnosis, and management of Aspergillus after organ transplantation. Aspergillus is the most common invasive mold infection in solid-organ transplant (SOT) recipients, and it is the most common invasive fungal infection among lung transplant recipients. Time from transplant to diagnosis of invasive aspergillosis (IA) is variable, but most cases present within the first year post-transplant, with shortest time to onset among liver and heart transplant recipients. The overall 12-week mortality of IA in SOT exceeds 20%; prognosis is worse among those with central nervous system involvement or disseminated disease. Bronchoalveolar lavage galactomannan is preferred for the diagnosis of IA in lung and non-lung transplant recipients, in combination with other diagnostic modalities (eg, chest CT scan, culture). Voriconazole remains the drug of choice to treat IA, with isavuconazole and lipid formulations of amphotericin B regarded as alternative agents. The role of combination antifungals for primary therapy of IA remains controversial. Either universal prophylaxis or preemptive therapy is recommended in lung transplant recipients, whereas targeted prophylaxis is favored in liver and heart transplant recipients. In these guidelines, we also discuss newer antifungals and diagnostic tests, antifungal susceptibility testing, and special patient populations.

Fungal Infections After Lung Transplantation

Infection remains a significant source of morbidity and mortality after lung transplant, including fungal infection. Various antifungal prophylactic agents are administered for a variable duration after transplant with the goal of preventing invasive fungal infections. Alternatively, some programs target the use of antifungal agents only in those colonized with Aspergillus spp. Despite prophylaxis or preemptive therapy, a significant number of invasive fungal infections occur after lung transplant. Risk factors for fungal infections include single lung transplant, pretransplant Aspergillus colonization, environmental risks, structural lung disease such as cystic fibrosis, augmented immunosuppression, sinus disease, and use of indwelling airway stents.

Complications of invasive mycoses in organ transplant recipients

INTRODUCTION

Opportunistic mycoses remain a significant complication in organ recipients. Areas covered: This review is an evidence-based presentation of current state-of-knowledge and our perspective on recent developments in the field Expert commentary: Invasive fungal infections are associated with reduced allograft and patient survival, increase in healthcare resource utilization, and newly appreciated but largely unrecognized immunologic sequelae, such as immune reconstitution syndrome. Given adverse outcomes associated with established infections, prophylaxis is a widely used strategy for the prevention of these infections. Currently available biomarkers that detect circulating fungal cell wall constituents i.e., galactomannan and 1, 3-β-D-glucan have not proven to be beneficial as screening tools for employing targeted prophylaxis or as diagnostic assays in this patient population. However, subsets of patients at risk for opportunistic fungal infections can be identified based on clinically identifiable characteristics or events. Preventive strategies targeted towards these patients are a rational approach for optimizing outcomes.

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.

Clinical pharmacokinetics of inhaled antimicrobials

Administration of inhaled antimicrobials affords the ability to achieve targeted drug delivery into the respiratory tract, rapid entry into the systemic circulation, high bioavailability and minimal metabolism. These unique pharmacokinetic characteristics make inhaled antimicrobial delivery attractive for the treatment of many pulmonary diseases. This review examines recent pharmacokinetic trials with inhaled antibacterials, antivirals and antifungals, with an emphasis on the clinical implications of these studies. The majority of these studies revealed evidence of high antimicrobial concentrations in the airway with limited systemic exposure, thereby reducing the risk of toxicity. Sputum pharmacokinetics varied widely, which makes it challenging to interpret the result of sputum pharmacokinetic studies. Many no vel inhaled antimicrobial therapies are currently under investigation that will require detailed pharmacokinetic studies, including combination inhaled antimicrobial therapies, inhaled nanoparticle formulations of several antibacterials, inhaled non-antimicrobial adjuvants, inhaled antiviral recombinant protein therapies and semi-synthetic inhaled antifungal agents. Additionally, the development of new inhaled delivery devices, particularly for mechanically ventilated patients, will result in a pressing need for additional pharmacokinetic studies to identify optimal dosing regimens.

Risks and Epidemiology of Infections After Lung or Heart–Lung Transplantation

Nowadays, lung transplantation is an established treatment option of end-stage pulmonary parenchymal and vascular disease. Post-transplant infections are a significant contributor to overall morbidity and mortality in the lung transplant recipient that, in turn, are higher than in other solid organ transplant recipients. This is likely due to several specific factors such as the constant exposure to the outside environment and the colonized native airway, and the disruption of usual mechanisms of defense including the cough reflex, bronchial circulation, and lymphatic drainage. This chapter will review the common infections that develop in the lung or heart–lung transplant recipient, including the general risk factors for infection in this population, and specific features of prophylaxis and treatment for the most frequent bacterial, viral, and fungal infections. The effects of infection on lung transplant rejection will also be discussed.

The Impact of Infection on Chronic Allograft Dysfunction and Allograft Survival After Solid Organ Transplantation

Infectious diseases after solid organ transplantation (SOT) are a significant cause of morbidity and reduced allograft and patient survival; however, the influence of infection on the development of chronic allograft dysfunction has not been completely delineated. Some viral infections appear to affect allograft function by both inducing direct tissue damage and immunologically related injury, including acute rejection. In particular, this has been observed for cytomegalovirus (CMV) infection in all SOT recipients and for BK virus infection in kidney transplant recipients, for community-acquired respiratory viruses in lung transplant recipients, and for hepatitis C virus in liver transplant recipients. The impact of bacterial and fungal infections is less clear, but bacterial urinary tract infections and respiratory tract colonization by Pseudomonas aeruginosa and Aspergillus spp appear to be correlated with higher rates of chronic allograft dysfunction in kidney and lung transplant recipients, respectively. Evidence supports the beneficial effects of the use of antiviral prophylaxis for CMV in improving allograft function and survival in SOT recipients. Nevertheless, there is still a need for prospective interventional trials assessing the potential effects of preventive and therapeutic strategies against bacterial and fungal infection for reducing or delaying the development of chronic allograft dysfunction.

Occupational and environmental bronchiolar disorders

Occupational and environmental causes of bronchiolar disorders are recognized on the basis of case reports, case series, and, less commonly, epidemiologic investigations. Pathology may be limited to the bronchioles or also involve other components of the respiratory tract, including the alveoli. A range of clinical, functional, and radiographic findings, including symptomatic disease lacking abnormalities on noninvasive testing, poses a diagnostic challenge and highlights the value of surgical biopsy. Disease clusters in workplaces and communities have identified new etiologies, drawn attention to indolent disease that may otherwise have been categorized as idiopathic, and expanded the spectrum of histopathologic responses to an exposure. More sensitive noninvasive diagnostic tools, evidence-based therapies, and ongoing epidemiologic investigation of at-risk populations are needed to identify, treat, and prevent exposure-related bronchiolar disorders.

Inhaled anti-infective chemotherapy for respiratory tract infections: successes, challenges and the road ahead

One of the most common causes of illnesses in humans is from respiratory tract infections caused by bacterial, viral or fungal pathogens. Inhaled anti-infective drugs are crucial for the prophylaxis and treatment of respiratory tract infections. The benefit of anti-infective drug delivery via inhalation is that it affords delivery of sufficient therapeutic dosages directly to the primary site of infection, while minimizing the risks of systemic toxicity or avoiding potential suboptimal pharmacokinetics/pharmacodynamics associated with systemic drug exposure. This review provides an up-to-date treatise of approved and novel developmental inhaled anti-infective agents, with particular attention to effective strategies for their use, pulmonary pharmacokinetic properties and safety.

Major complications of adult right lobe living liver donors

BACKGROUND

The right lobe of the liver is generally preferred for living donor liver transplantation in adult patients with end-stage liver disease. It is important to know the preoperative factors relating to the major postoperative complications. We therefore evaluated the possible risk factors for predicting postoperative complications in right lobe liver donors.

METHODS

Data from 378 donors who had undergone right lobe hepatectomy at our center were evaluated retrospectively. The factors we evaluated included donor age, gender, body mass index (BMI), remnant liver volume, operation time, history of previous abdominal surgery, inclusion of the middle hepatic vein and variations in the portal and bile systems.

RESULTS

Of the 378 donors, 219 were male and 159 female. None of the donors died, but 124 (32.8%) donors experienced complications including major complications (Clavien scores III and IV) in 27 (7.1%). Univariate analysis showed that complications were significantly associated with male gender and higher BMI (P<0.05), but not with donor age, remnant liver volume, operation time, graft with middle hepatic vein, variations in the portal and bile systems and previous abdominal surgery (P<0.05). Multivariate logistic regression analysis showed that major complications were significantly associated with male gender (P=0.005) and higher BMI (P=0.029). Moreover, the Chi-square test showed that there were significant relationships between major complications and male gender (P=0.010, X2=6.614, df=1) and BMI >25 kg/m2 (P=0.031, X2=8.562, df=1). Of the 96 male donors with BMI >25 kg/m2, 14 (14.6%) with major complications had significantly smaller mean remnant liver volume than those (82, 85.4%) without major complications (32.50%+/-4.45% vs 34.63%+/-3.11%, P=0.029).

CONCLUSION

Male donors with BMI >25 kg/m2 and a remnant liver volume ≤32.50% had a significantly increased risk for major complications.

Aerosolized liposomal Amphotericin B: a potential prophylaxis of invasive pulmonary aspergillosis in immunocompromised patients

BACKGROUND

Aerosolized liposomal Amphotericin B may reduce the incidence of invasive pulmonary Aspergillosis in adults with chemotherapy-induced prolonged neutropenia with less nephrotoxicity. The breath-actuated AeroEclipse® BAN nebulizer is very efficient and minimizes environmental drug contamination since no aerosol is produced, unless the patient is inspiring through the device. Our aim is to develop an appropriate delivery system suitable for children that does not disrupt the liposomes due to the shear forces in nebulization.

METHODS

This is an in vitro experimental study in vitro. Six ml of 4 mg/ml liposomal Amphotericin B solution (AmBisome®; Astellas Pharma Inc., Markham, Ontario, CA) was nebulized with the breath-actuated nebulizer (AeroEclipse®; Trudell Medical International, Canada) and captured by the glass liquid impinger. Sodium dodecyl sulfate was used as detergent to disrupt the liposomes in control samples. Gel filtration, electron microscopy, and high performance liquid chromatography (HPLC) were used to compare the size and shape of the liposomes, and amount of the drug before and after nebulization. The aerosol particle size was obtained by the laser diffraction.

RESULTS

After nebulization, 97.5% of amphotericin B was captured by the liquid impinger and detected by HPLC. Gel filtration and electron microscopy demonstrated that the drug remained in its liposomal configuration after nebulization. The mass median diameter (MMD) was 3.7 μm and 66% of aerosol particles were less than 5 μm in diameter.

CONCLUSIONS

We demonstrated that liposomal Amphotericin B can be nebulized successfully without disrupting the liposomes and minimize drug loss by using the breath-actuated nebulizer.

Mechanisms of absorption and elimination of drugs administered by inhalation

Pulmonary drug delivery is an effective route for local or systemic drug administration. However, compared with other routes of administration, there is a scarcity of information on how drugs are absorbed from the lung. The different cell composition lining the airways and alveoli makes this task extremely complicated. Lung cell lines and primary culture cells are useful in studying the absorption mechanisms. However, it is imperative that these cell cultures express essential features required to study these mechanisms such as intact tight junctions and transporters. In vivo, the drug has to face defensive physical and immunological barriers such as mucociliary clearance and alveolar macrophages. Knowledge of the physicochemical properties of the drug and aerosol formulation is required. All of these factors interact together leading to either successful drug deposition followed by absorption or drug elimination. These aspects concerning drug transport in the lung are addressed in this review.

Penetration of anti-infective agents into pulmonary epithelial lining fluid: focus on antifungal, antitubercular and miscellaneous anti-infective agents

Epithelial lining fluid (ELF) is often considered to be the site of extracellular pulmonary infections. During the past 25 years, a limited number of studies have evaluated the intrapulmonary penetration of antifungal, antitubercular, antiparasitic and antiviral agents. For antifungal agents, differences in drug concentrations in ELF or bronchoalveolar lavage (BAL) fluid were observed among various formulations or routes of administration, and between agents within the same class. Aerosolized doses of deoxycholate amphotericin B, liposomal amphotericin B and amphotericin B lipid complex resulted in higher concentrations in ELF or BAL fluid than after intravenous administration. The mean concentrations in ELF following intravenous administration of both anidulafungin and micafungin ranged between 0.04 and 1.38 μg/mL, and the ELF to plasma concentration ratios (based on the area under the concentration-time curve for total drug concentrations) were between 0.18 and 0.22 during the first 3 days of therapy. Among the azole agents, intravenous administration of voriconazole resulted in the highest mean ELF concentrations (range 10.1-48.3 μg/mL) and ratio of penetration (7.1). The range of mean ELF concentrations of itraconazole and posaconazole following oral administration was 0.2-1.9 μg/mL, and the ELF to plasma concentration ratios were <1. A series of studies have evaluated the intrapulmonary penetration of first- and second-line oral antitubercular agents in healthy adult subjects and patients with AIDS. The ELF to plasma concentration ratio was >1 for isoniazid, ethambutol, pyrazinamide and ethionamide. For rifampicin (rifampin) and rifapentine, the ELF to plasma concentration ratio ranged between 0.2 and 0.32, but in alveolar macrophages the concentration of rifampicin was much higher (145-738 μg/mL compared with 3.3-7.5 μg/mL in ELF). No intrapulmonary studies have been conducted for rifabutin. Sex, AIDS status or smoking history had no significant effects on the magnitude of ELF concentrations of antitubercular agents. Subjects who were slow acetylators had higher plasma and ELF concentrations of isoniazid than those who were fast acetylators. Penetration of dapsone into ELF was very good, with the range of mean ELF to plasma concentration ratios being 0.65-2.91 at individual sampling times over 48 hours. Once-daily dosing of aerosolized pentamidine resulted in higher concentrations in BAL fluid than after intravenous administration. The mean BAL concentrations at 15-32 days after once- or twice-monthly administration of aerosolized pentamidine 300 and 600 mg ranged from 6.5 to 28.4 ng/mL. No differences in pentamidine BAL concentrations were observed in symptomatic patients who developed Pneumocystis jirovecii pneumonia compared with patients who did not. Zanamivir concentrations in ELF were similar in magnitude (range 141-326 ng/mL) following administration by continuous intravenous infusion (3 mg/hour), oral inhalation (10 mg every 12 hours) and intravenous bolus (200 mg every 12 hours). Data from case reports have suggested that concentrations of nelfinavir and saquinavir in ELF are undetectable, whereas tipranavir and lopinavir had measureable ELF concentrations (2.20 μmol/L and 14.4 μg/mL, respectively) when these protease inhibitors were co-administrated with ritonavir. While the clinical significance of ELF or BAL concentrations remains unknown for this group of anti-infective agents, the knowledge of drug penetration into the extracellular space of the lung should assist in re-evaluating and designing specific dosing regimens for use against potential pathogens.

Amphotericin B lipid nanoemulsion aerosols for targeting peripheral respiratory airways via nebulization

Amphotericin B (AmB) lipid nanoemulsions were prepared and characterized and their suitability for pulmonary delivery via nebulization was evaluated. AmB nanoemulsions were prepared by sonicating and vortexing the drug with two commercially available lipid nanoemulsions: the Intralipid(®) or Clinoleic(®). Loading the nanoemulsions with the drug slightly increased the size of the lipid droplets and did not affect the zeta potential of the nanoemulsions. The loading efficiency of AmB was found to be 87.46±2.21% in the Intralipid(®) nanoemulsions and 80.7±0.70% in the Clinoleic(®) formulation. This respectively corresponded to 21.86 mg and 20.19 mg of AmB being successfully loaded in the nanoemulsions. On aerosolization using a Pari Sprint jet nebulizer, both nanoemulsions produced very high drug output which was approximately 90% for both formulations. Using the two-stage impinger, the Clinoleic(®) emulsion had higher fine particle fraction (FPF) than the Intralipid(®), since the Clinoleic(®) displayed higher deposition of AmB in the lower impinger stage (exceeding 80%), compared to 57% for the Intralipid(®). Overall, the ease of preparation of the AmB lipid nanoemulsions, along with their in vitro nebulization performance suggest that lipid nanoemulsions could be successful nanocarriers for delivery of AmB to the peripheral respiratory airways.

Multidisciplinary approach to the treatment of invasive fungal infections in adult patients. Prophylaxis, empirical, preemptive or targeted therapy, which is the best in the different hosts?

The high morbidity, mortality, and health care costs associated with invasive fungal infections, especially in the critical care setting and immunocompromised host, have made it an excellent target for prophylactic, empiric, and preemptive therapy interventions principally based on early identification of risk factors. Early diagnosis and treatment are associated with a better prognosis. In the last years there have been important developments in antifungal pharmacotherapy. An approach to the new diagnosis tools in the clinical mycology laboratory and an analysis of the use new antifungal agents and its application in different clinical situations has been made. Furthermore, an attempt of developing a state of the art in each clinical scenario (critically ill, hematological, and solid organ transplant patients) has been performed, trying to choose the best strategy for each clinical situation (prophylaxis, pre-emptive, empirical, or targeted therapy). The high mortality rates in these settings make mandatory the application of early de-escalation therapy in critically ill patients with fungal infection. In addition, the possibility of antifungal combination therapy might be considered in solid organ transplant and hematological patients.

[The lungs and immunosuppressants: practical problems]

With a growing number of patients receiving immunosuppressive drugs, lung specialists are faced with new problems. This review addresses: 1: specific interactions between some pre-existing respiratory diseases (asthma, bronchiectasis, infiltrative lung disease, repeated pneumonia, etc) and immunosuppressants; 2: some particular issues in the care of respiratory complications (infections, thoracic surgery, neoplasia, thromboembolism, etc) in patients undergoing immunosuppressive treatment.

Aerosolized Delivery of Antifungal Agents

Pulmonary infections caused by Aspergillus species are associated with significant morbidity and mortality in immunocompromised patients. Although the treatment of pulmonary fungal infections requires the use of systemic agents, aerosolized delivery is an attractive option in prevention because the drug can concentrate locally at the site of infection with minimal systemic exposure. Current clinical evidence for the use of aerosolized delivery in preventing fungal infections is limited to amphotericin B products, although itraconazole, voriconazole, and caspofungin are under investigation. Based on conflicting results from clinical trials that evaluated various amphotericin B formulations, the routine use of aerosolized delivery cannot be recommended. Further research with well-designed clinical trials is necessary to elucidate the therapeutic role and risks associated with aerosolized delivery of antifungal agents. This article provides an overview of aerosolized delivery systems, the intrapulmonary pharmacokinetic properties of aerosolized antifungal agents, and key findings from clinical studies.

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.

Fungal infections after lung transplantation

PURPOSE OF REVIEW

Lung transplant's Achilles heel is chronic rejection. This is the reason why high immunosuppression is used, which leads to the development of infections. Fungal infections are a great obstacle in lung transplant patients' progress, not only because of their impact on patient survival, but also because fungal infections indirectly have an influence on the graft's progress. This review highlights the changing spectrum of invasive fungal infections as well as the most recent developments in diagnosis, prophylaxis, treatment and monitoring of lung transplantation.

RECENT FINDINGS

Fungal infections have a bimodal presentation: early onset, in relation to difficult postsurgeries and prior colonizations, and late onset, primarily in relation to chronic rejection and terminal renal insufficiency. The clinical impact of non-Aspergillus moulds is still unknown. Recent efforts have focused on nonculture-based methods to establish a rapid diagnosis. However, multicentre studies are needed to establish the diagnostic value of galactomannan antigen assay in invasive aspergillosis in lung transplantation. In addition, studies of the sensitivity and specificity of PCR assays are required to establish their diagnostic value. Unfortunately, only some advances in the diagnosis of aspergillosis have been achieved.

SUMMARY

Prophylaxis should be tailored according to the different individual patient's risk status. Combined treatments, including surgical therapy, may be useful in some patients.

Efficiency and safety of inhaled amphotericin B lipid complex (Abelcet) in the prophylaxis of invasive fungal infections following lung transplantation

BACKGROUND

Invasive fungal infections (IFIs) in patients undergoing lung transplantation (LT) are associated with significant mortality. Previous studies have shown the efficacy of aerosolized amphotericin B deoxycholate and oral fluconazole for antifungal prophylaxis. Evolving data show a potential advantage of prophylaxis with lipid-based formulations of amphotericin B in the prevention of IFIs. We reviewed the incidence of IFIs among patients receiving aerosolized amphotericin B lipid complex (ABLC) in LT.

METHODS

We undertook a retrospective review of the results of our antifungal protocol in a cohort of 60 LT patients. We analyzed the efficiency, safety, and tolerability of 50 mg of aerosolized ABLC administered postoperatively for IFI prophylaxis once every 2 days for 2 weeks and then once per week for at least 13 weeks. In addition, these transplanted patients received fluconazole (200 mg/d) during the first 21 days posttransplant. The prophylaxis-related efficiency and safety were quantified for IFIs and adverse events (AEs) for 6 months after study drug initiation.

RESULTS

Prophylaxis was efficient in 59 (98.3%) patients. Only one patient developed a possible IFI, due to Aspergillus fumigatus. Four patients presented nausea and vomiting as an AE, although aerosolized amphotericin B was ongoing.

CONCLUSIONS

Nebulized ABLC was effective, safe, and well tolerated for the prophylaxis of aspergillosis in lung transplant patients during the early posttransplant period.

Aerosol drug delivery in lung transplant recipients

BACKGROUND

Inhaled drug delivery after lung transplantation provides a unique opportunity for direct treatment of a solid organ transplant. At present, no inhaled therapies are approved for this population though several have received some development. Primary potential applications include inhaled immunosuppressive and anti-infective drugs.

OBJECTIVES

The objective of this article is to review potential applications of inhaled medications for lung transplant recipients, the techniques used to develop inhaled drugs and the challenges of aerosol delivery in this specific population.

METHODS

The results of relevant studies are reviewed and two developmental examples are presented.

RESULTS/CONCLUSIONS

Inhaled medications may provide significant advantages for lung transplant recipients. Past studies with inhaled cyclosporine and amphotericin-B provide useful guidance for clinical development of new preparations.

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.