A randomized trial of inhaled cyclosporine in lung-transplant recipients

Orthotopic mouse lung transplantation as experimental methodology to study transplant and tumor biology

Unlike transplantation of other solid organs, vascularized mouse lung transplantation has only recently been developed. In this protocol, we describe a detailed method for performing a vascularized and aerated mouse orthotopic lung transplant, which to date represents the most physiological mouse model of lung transplantation. The procedure is divided into two separate portions consisting of donor harvest followed by implantation using the cuff technique for bronchovascular anastomoses. After a training period spanning several months, the procedure can be successfully mastered and, in experienced hands, requires approximately 90 min to perform. After an initial learning curve, perioperative survival is close to 100%. As the donor hematopoietic cells in the transplanted lung are replaced by those of the host over time, thereby creating a 'chimeric lung,' this model represents a novel research tool for the study of transplantation biology as well as other disease processes, such as malignancies.

Technology and outcomes assessment in lung transplantation

Lung transplantation offers the hope of prolonged survival and significant improvement in quality of life to patients that have advanced lung diseases. However, the medical literature lacks strong positive evidence and shows conflicting information regarding survival and quality of life outcomes related to lung transplantation. Decisions about the use of lung transplantation require an assessment of trade-offs: do the potential health and quality of life benefits outweigh the potential risks and harms? No amount of theoretical reasoning can resolve this question; empiric data are needed. Rational analyses of these trade-offs require valid measurements of the benefits and harms to the patients in all relevant domains that affect survival and quality of life. Lung transplant systems and registries mainly focus outcomes assessment on patient survival on the waiting list and after transplantation. Improved analytic approaches allow comparisons of the survival effects of lung transplantation versus continued waiting. Lung transplant entities do not routinely collect quality of life data. However, the medical community and the public want to know how lung transplantation affects quality of life. Given the huge stakes for the patients, the providers, and the healthcare systems, key stakeholders need to further support quality of life assessment in patients with advanced lung disease that enter into the lung transplant systems. Studies of lung transplantation and its related technologies should assess patients with tools that integrate both survival and quality of life information. Higher quality information obtained will lead to improved knowledge and more informed decision making.

Immunosuppression for lung transplantation

As a result of advances in surgical techniques, immunosuppressive therapy, and postoperative management, lung transplantation has become an established therapeutic option for individuals with a variety of end-stage lung diseases. The current 1-year actuarial survival rate following lung transplantation is approaching 80%. However, the 5- year actuarial survival rate has remained virtually unchanged at approximately 50% over the last 15 years due to the processes of acute and chronic lung allograft rejection (1). Clinicians still rely on a vast array of immunosuppressive agents to suppress the process of graft rejection, but find themselves limited by an inescapable therapeutic paradox. Insufficient immunosuppression results in graft loss due to rejection, while excess immunosuppression results in increased morbidity and mortality from opportunistic infections and malignancies. Indeed, graft rejection, infection, and malignancy are the three principal causes of mortality for the lung transplant recipient. One should also keep in mind that graft loss in a lung transplant recipient is usually a fatal event, since there is no practical means of long-term mechanical support, and since the prospects of re-transplantation are low, given the shortage of acceptable donor grafts. This chapter reviews the current state of immunosuppressive therapy for lung transplantation and suggests alternative paradigms for the management of future lung transplant recipients.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Bronchiolitis obliterans syndrome: alloimmune-dependent and -independent injury with aberrant tissue remodeling

Long-term success in lung transplantation continues to be challenged by chronic graft dysfunction, which is manifest as bronchiolitis obliterans syndrome (BOS). The mechanisms of BOS involve both immune-mediated pathways (rejection, autoimmune-like mechanisms), and alloimmune-independent pathways (infection, aspiration, ischemia, primary graft failure), which lead to a fibroproliferative responses. BOS correlates histologically with obliterative bronchiolitis in terminal bronchioles and evidence of aberrant remodeling in the airway epithelium, vasculature, stroma, and lymphoid system. A potentially important mechanism that supports the progressive and therapy-resistant nature of BOS is a continuous cycle of ongoing injury and aberrant remodeling. Namely, anatomical and functional abnormalities induce and exacerbate immune-mediated and alloimmune-independent pathways through various mechanisms (e.g., epithelial remodeling decreases mucociliary clearance that exacerbates aspiration-related injury). From this viewpoint, we review current therapeutic strategies and revisit the role of transplant surgeons in attenuating the initial transplant-related injuries to prevent the lung grafts from entering the remodeling-injury cycle.

MegaRibavirin aerosol for the treatment of influenza A virus infections in mice

While newer neuraminidase inhibitors have been used recently to treat influenza A and B virus infections, emergence of drug resistance poses potential problems. Previous ribavirin aerosol treatments of influenza were effective and drug resistance was not observed. To make ribavirin aerosol treatment a quicker process and limited to once or twice daily treatments, a MegaRibavirin formulation (100 mg of ribavirin/mL) was developed that when used with the Aerotech II nebulizer was effective in preventing death in a lethal influenza A virus mouse model. Aerosol generated using the Aerotech II nebulizer flowing at 10 L of air/min produced aerosol droplets that contained 2.3 mg of ribavirin/L with a mass median aerodynamic diameter of 1.8 microm. Using this system for treatment, a single daily 30-min exposure on days 1-4 produced a survival rate of greater than 90%. Delaying the start of aerosol treatment for 48 or 72 h and treating once daily for 30 min for two days (days 2-3 and 3-4, respectively) still significantly increased the number of survivors and mean time to death. For the treatment of influenza in general and for pandemic avian influenza, the MegaRibavirin-Aerotech II method of aerosol treatment allows for short treatment periods, minimizes environmental issues and costs less.

Bronchiolitis obliterans syndrome (BOS), bronchiolitis obliterans organizing pneumonia (BOOP), and other late-onset noninfectious pulmonary complications following allogeneic hematopoietic stem cell transplantation

Pulmonary dysfunction is a significant complication following allogeneic hematopoietic stem cell transplantation (HSCT), and is associated with significant morbidity and mortality. Effective antimicrobial prophylaxis and treatment strategies have increased the incidence of noninfectious lung injury, which can occur in the early posttransplant period or in the months and years that follow. Late-onset noninfectious pulmonary complications are frequently encountered, but diagnostic criteria and terminology for these disorders can be confusing and therapeutic approaches are suboptimal. As a consequence, inaccurate diagnosis of these conditions may hamper the appropriate data collection, enrollment into clinical trials, and appropriate patient care. The purpose of this review is to clarify the pathogenesis and diagnostic criteria of representative conditions, such as bronchiolitis obliterans syndrome and bronchiolitis obliterans organizing pneumonia, and to discuss the appropriate diagnostic strategies and treatment options.

Lung transplantation for cystic fibrosis: Current concepts and one center's experience

BACKGROUND

Although new approaches to the treatment of patients with cystic fibrosis (CF) are significantly prolonging their lives, most patients will eventually develop respiratory failure due to progressive bronchiectasis caused by chronic lung infection and inflammation and die from to respiratory failure. We examined our center's (University of Wisconsin Hospital and Clinics) experience with lung transplantation for patients with CF and reviewed the literature to examine current and evolving approaches to transplantation for this indication.

METHODS

We reviewed all published literature pertaining to lung transplantation for CF through 2006, and we reviewed all aspects of transplantation for patients with CF at our institution from 1994 to 2005.

RESULTS

Major complications following lung transplantation include acute rejection, bacterial infection, and bronchiolitis obliterans. Five-year survival at UWHC (Kaplan-Meier) is 67%, and survival was not adversely affected by transplanting patients receiving mechanical ventilation. The major cause of death for transplant recipients was bronchiolitis obliterans syndrome (BOS).

CONCLUSIONS

Lung transplantation for CF is associated with acceptable survival rates and can improve quality of life. Lung transplant should be offered to all patients with advanced CF lung disease if they meet currently accepted inclusion and exclusion criteria.

The Challenges of Quantitative Measurement of Lung Deposition Using 99mTc-DTPA from Delivery Systems with Very Different Delivery Times

In quantifying aerosol delivery, the drug is often mixed with a radiolabel such as (99m)Tc-DTPA whose deposition is used as a proxy for the drug. (99m)Tc-DTPA deposited in the lung is cleared by a combination of absorption into the pulmonary circulation and mucociliary clearance. If administration is not instantaneous, the image will not include that clearance during administration, a problem raised if comparing devices with different administration times. However, if rates of clearance are measured, it will be possible to "correct" the initial image for the clearance that occurred during administration and before counting. Five adult males inhaled a 5-mL solution containing (99m)Tc-DTPA from a breath enhanced jet nebulizer (LC Plus)over the course of 10 min and a 1.25-mL solution from a vibrating membrane device (eFlow), which was delivered in 2.5 min. Quality assurance was the radioactivity count balance (RCB) defined as the difference in the total radioactivity pre-nebulization less post, divided by pre, and expressed as a percentage. Attenuation calculations used a (57)Co flood source (Macey and Marshall). The "correction" for the clearance of (99m)Tc-DTPA was 0.91 +/- 0.04 (mean +/- SD) for the LC Plus) and 0.96 +/- 0.02 for the eFlow). RCB was -0.6 +/- 3.5% for the LC Plus and -4.7 +/- 6.4% for the eFlow, implying acceptable accuracy. For the LC Plus, lung deposition was 15.9(13.4, 18.4)% (mean and 95% CI) of the charge dose, and for the eFlow it was 32.0(29.0, 35.0)%. This technique gave an acceptable level of accuracy for quantitative planar imaging and allowed the comparison of delivery from devices with very different rates of delivery.

Effect of inhaled tacrolimus on cellular and humoral rejection to prevent posttransplant obliterative airway disease

This study aimed to investigate the pharmacokinetics after tacrolimus aerosol inhalation and to assess its efficacy to suppress acute and chronic airway allograft rejection. Orthotopic tracheal transplantations were performed and tacrolimus (4 mg/kg) was administered orally (PO) or via aerosol (AER). Tracheal tissue level AUCs(0-12) were similar in both treatment groups, but blood AUCs(0-12) were approximately 5.5-fold lower with AER (p < 0.001). Interestingly, only PO animals showed elevated BUN, cholesterol and triglycerides on POD 60 (p < 0.05). Histology of grafts harvested after 6 and 60 days revealed that both treatment groups were similarly effective in suppressing graft mononuclear infiltration (p < 0.001). Cellular immune activation (assessed by IFN-gamma- and IL-4-ELISPOTS), however, was far more effectively suppressed by tacrolimus PO (p < 0.001). In both treatment groups, the vigorous alloreactive IgM-antibody surge was effectively inhibited (p < 0.001). Due to the insufficient systemic cellular immunosuppression, discontinuation of tacrolimus AER resulted in a far stronger (3.5-fold) graft infiltration on POD 8 compared to PO (p < 0.001). Tacrolimus aerosol reduces systemic side effects and effectively protects the airway graft from early cellular rejection and chronic obliterative airway disease.

Characterization of a cyclosporine solid dispersion for inhalation

For lung transplant patients, a respirable, inulin-based solid dispersion containing cyclosporine A (CsA) has been developed. The solid dispersions were prepared by spray freeze-drying. The solid dispersion was characterized by water vapor uptake, specific surface area analysis, and particle size analysis. Furthermore, the mode of inclusion of CsA in the dispersion was investigated with Fourier transform infrared spectroscopy. Finally, the dissolution behavior was determined and the aerosol that was formed by the powder was characterized. The powder had large specific surface areas (~ 160 m(2)). The water vapor uptake was dependant linearly on the drug load. The type of solid dispersion was a combination of a solid solution and solid suspension. At a 10% drug load, 55% of the CsA in the powder was in the form of a solid solution and 45% as solid suspension. At 50% drug load, the powder contained 90% of CsA as solid suspension. The powder showed excellent dispersion characteristics as shown by the high emitted fraction (95%), respirable fraction (75%), and fine-particle fraction (50%). The solid dispersions consisted of relatively large (x(50) approximately 7 mum), but low-density particles (rho approximately 0.2 g/cm(3)). The solid dispersions dissolved faster than the physical mixture, and inulin dissolved faster than CsA. The spray freeze-drying with inulin increased the specific surface area and wettability of CsA. In conclusion, the developed powder seems suitable for inhalation in the local treatment of lung transplant patients.

Techniques for experimental heterotopic and orthotopic tracheal transplantations — When to use which model?

BACKGROUND

Different animal models have been developed to study the pathogenesis and treatment of obliterative airway disease (OAD). Here we describe the techniques of heterotopic and orthotopic tracheal transplantations in the rat, comparing the kinetics of systemic host immune response and of histopathologic OAD development.

METHODS

Heterotopic and orthotopic tracheal transplantations were performed in both allogeneic (Brown Norway-to-Lewis) and syngeneic (Lewis-to-Lewis) models. Grafts were harvested after 7, 30, and 60 days post-transplant for histologic evaluation and analysis of host cellular and humoral response.

RESULTS

Syngeneic tracheal grafts did not develop luminal obliteration and were morphologically indistinguishable from native tracheas. In heterotopic allografts, airway epithelium was rapidly destroyed and OAD progressed with complete luminal occlusion by 30 days. Orthotopic allografts showed enhanced early infiltration (1298+/-45 vs. 674+/-75 cells/high power field, p<0.001) with concomitant greater day 7 luminal narrowing (45+/-6% vs. 14+/-3%, p<0.001). In this model, donor-type BN epithelium (62+/-17%, 21+/-19%, and 1+/-1% on days 7, 30, and 60) was gradually replaced by recipient-type epithelial cells (2+/-4%, 70+/-22%, and 98+/-2%). OAD developed with circular orientation of cells and connective tissue fibers to 45+/-6% obliteration by day 60. Cellular host response, as determined by IFN-gamma-ELISPOT assay (548+/-132 vs. 402+/-197 spots, p=0.046) and anti-donor alloreactive IgM antibody production (2827+/-148 vs. 1565+/-393 mean channel fluorescence, p<0.001) were significantly stronger in rats bearing orthotopic vs. heterotopic allografts.

CONCLUSIONS

The orthotopic tracheal transplantation model may be more representative of OAD found in human lung transplant recipients and we therefore encourage the wider use of this model.

Harnessing calcineurin as a novel anti-infective agent against invasive fungal infections

The number of immunocompromised patients with invasive fungal infections continues to increase and new antifungal therapies are not keeping pace with the growing incidence of these infections and their associated mortality. Calcineurin inhibition is currently used to exert effective immunosuppression following organ transplantation and in treating various other conditions. However, the calcineurin pathway is also intricately involved in the growth and pathogenesis of the three major fungal pathogens of humans, Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus, and the exploitation of fungal calcineurin pathways holds great promise for the future development of novel antifungal agents. This Review summarizes our current understanding of calcineurin biology in these fungal species, and its exciting potential role in treating invasive fungal infections.

Emerging drugs in lung transplantation

The balance between immunosuppression to ensure graft tolerance while preventing emergence of infectious complications is key in lung transplantation. Although opportunistic infection may appear to be the most important of these complications, malignancies and severe drug toxicities significantly affect the short- and long-term outcomes of the patients. The present practice is combination therapy using drugs with complementary immunosuppressive action, to achieve synergistic immunosuppression with the lowest possible toxicity. Components of immunosuppression include induction and maintenance regimens. Primary graft failure remains an important cause of mortality and morbidity in the immediate post-transplant period. Acute rejection is a common complication after lung transplant, but responds well to augmented immunosuppression and immunomodulation. Chronic rejection still is the major cause of mortality in patients who survive the initial year post-transplantation. Several new drugs have shown promise in decreasing the rate of loss of graft function. This review discusses the current and emerging therapeutic regimens.

Lung transplantation

PURPOSE OF REVIEW

To describe recent advances in lung transplantation relevant to anesthesiologists.

RECENT FINDINGS

There is recent literature describing medical, surgical, anesthetic and critical care of lung transplant recipients.

SUMMARY

There have been substantial changes in preoperative selection and preparation of lung transplant recipients; these include donation after cardiac death, and improved lung-preservation solutions. Newer immunosuppression regimens have been successfully evaluated in clinical trials. Particular advances in anesthesia include endorsement of fluid restriction in thoracic surgery, greater use of transesophageal echocardiography, and postoperative extracorporeal membrane oxygenation.

Genetic regulation of rejection and survival following human lung transplantation by the innate immune receptor CD14

We have developed the hypothesis that genetic polymorphisms which alter the expression or function of innate immune receptors contribute to the marked interindividual differences in the onset and severity of lung transplant rejection. In this analysis, we considered the effects of a common promotor polymorphism of the lipopolysaccharide receptor CD14 associated with increased transcriptional activity upon the development of posttransplant rejection and graft survival. Genotyping was performed in 226 lung transplant recipients well characterized with regards to clinical outcomes. An earlier onset of acute rejection, bronchiolitis obliterans syndrome (BOS) and worse posttransplant graft survival due to greater BOS related deaths was evident in patients with the CD14 -159 TT genotype (TT). The adverse effect upon graft survival of the TT genotype remained significant in a multivariate Cox model (Hazard Ratio 1.65, 95% CI, 1.03-2.64, p-value = 0.04) after adjusting for other important covariates. Furthermore, TT patients have significantly greater sCD14, TNF-alpha and IFN-gamma in the peripheral blood implying a heightened state of innate immune activation drives the development of increased post-transplant rejection. Inhibition of innate immune activation through CD14 represents a novel and potentially important therapeutic target to prevent post-transplant rejection and improve outcomes after human lung transplantation.

Efficacy and safety of inhaled tacrolimus in rat lung transplantation

OBJECTIVE

Because acute rejection is the most important cause of chronic rejection in lung transplantation, the use of conventional systemic immunosuppression to improve long-term survival needs to be reassessed. The aim of this study was to investigate the efficacy and safety of inhaled tacrolimus for preventing acute rejection of rat lung allografts.

METHODS

Orthotopic left lung transplantation was performed in rats that were divided into 6 groups: control group received no treatment; groups 1.0-IM, 0.5-IM, and 0.3-IM received tacrolimus by intramuscular injection at 1.0, 0.5, and 0.3 mg/(kg.d), respectively; and groups 12-IT and 6-IT received 12 and 6 puffs of inhaled tacrolimus 3 times per day, respectively. Allografts were studied histologically. Whole blood and allograft tacrolimus concentrations were determined.

RESULTS

In groups 1.0-IM and 12-IT, histologic grade of the graft showed significantly less rejection than in the other groups. The blood tacrolimus concentration in group 12-IT (4.87 ng/mL) was significantly lower than that in group 1.0-IM (13.05 ng/mL, P = .0017) on postoperative day 7. Higher allograft tacrolimus concentrations were achieved in group 1.0-IM (478.0 ng/g) than in group 12-IT (270.4 ng/g, P = .009). Weight loss and diarrhea in group 12-IT were less severe than in the groups that received systemic tacrolimus. The proliferating cell nuclear antigen index in bronchus-associated lymphoid tissue cells was significantly lower in group 12-IT than in group 1.0-IM (P = .0209).

CONCLUSION

Local immunotherapy with inhaled tacrolimus has great potential for controlling pulmonary allograft rejection in clinical lung transplantation because it has fewer side effects than systemic immunosuppressive agents.

Early detection of chronic pulmonary allograft dysfunction by exhaled biomarkers

RATIONALE

Early detection of bronchiolitis obliterans syndrome (BOS) is important because therapies are more likely to be effective if employed early in the disease process.

OBJECTIVES

To compare the performance of exhaled NO and CO (which reflect airway inflammation) and the slope of the alveolar plateau for helium (which reflects heterogeneity of ventilation distribution) for detection of BOS stages 0-p and 1.

METHODS

Recipients of bilateral (n=64) and single (n=1) lung grafts were prospectively monitored for 1,249 days; the helium slope was derived from single-breath washouts and exhaled NO and CO were measured by chemiluminescence on 933 occasions.

MEASUREMENTS AND MAIN RESULTS

At the end of follow-up, 9 patients were in stage 0-p and 16 patients were in BOS stage 1 or higher; 21 patients had at least one measurement made in BOS stage 0-p. All markers increased in BOS stage 0-p, but only the helium slope increased in BOS stage 1. The helium slope had better sensitivity for detection of stages 0-p and 1 than either exhaled NO or CO, but considering exhaled NO and CO together improved their sensitivity; the best sensitivity was found with the three markers in combination. The biomarkers had high negative predictive values, but low specificity and positive predictive values.

CONCLUSIONS

After lung transplantation, (1) the helium slope and exhaled NO, but also exhaled CO, increase in BOS stage 0-p, (2) the helium slope has better sensitivity than exhaled NO and CO for the detection of BOS stages 0-p and 1, and (3) exhaled biomarkers have high negative predictive values, but low specificity and positive predictive values.

Disease, destination, dose and delivery aspects of ciclosporin: the state of the art

Since its discovery in 1971, ciclosporin has revolutionized organ transplantation and the treatment of autoimmune disorders. The wide array of applications resulting from its clinical efficacy warrant unique administration strategies and varying doses, times of exposure and extents of distribution, depending on target tissue. The poor biopharmaceutical characteristics of low solubility and permeability makes this uphill task even more challenging for the drug delivery scientist. Efforts underway have explored various body routes employing approaches like emulsions, microspheres, nanoparticles, liposomes, iontophoresis and penetration enhancers. This review attempts a brief holistic view of the "four Ds" (disease, destination, dose and delivery) surrounding this immunomodulator drug.

Aerosol deposition of lipid complex amphotericin-B (Abelcet) in lung transplant recipients

Lung transplant recipients exhibit a high incidence of invasive aspergillosis. The inhalation of lipid complex amphotericin-B (Abelcet; ABLC) offers a possible prophylactic strategy. The goals of this study were to select the optimal nebulizer delivery system for ABLC and to measure deposited aerosol dose in 12 lung transplant recipients. In vitro testing was performed to select a nebulizer delivery system, and an empirical model was used to estimate lung deposition. Estimated pulmonary doses varied by as much as 2-fold between different nebulizers. Aerosol deposition testing was performed in six single and six double lung recipients, each of whom received one 7 mL (35 mg) nebulized dose of Technetium-labeled ABLC using the selected nebulizer. In single lung recipients, the average deposited doses were 3.9 +/- 1.6 mg (mean +/- S.D.) in the allograft versus 2.1 +/- 1.1 mg in the native lung. Double lung recipients deposited on average 2.8 +/- 0.8 mg (left lung) and 4.0 +/- 1.3 mg (right lung). The drug was well distributed throughout the lungs, but delivery to the native lung was in some cases suboptimal. These studies provide an important precursor to studies of the efficacy of inhaled ABLC as a prophylaxis of invasive aspergillosis after lung transplant.

Inhaled delivery of aerosolized cyclosporine

Aerosolized cyclosporine was the first calcineurin inhibitor to be developed for inhaled administration. Its use as a topical immunosuppressant after lung transplantation is reviewed. Animal studies in transplant and non-transplant models are considered, as is nebulized delivery of the drug, including the results of scintigraphy and pharmacokinetic studies. Open label clinical studies of the drug for the treatment of chronic and acute lung transplant rejection are detailed. Placebo controlled trials for rejection prophylaxis are described and future directions for the drug are considered. Aerosol cyclosporine provides an excellent example of how inhaled aerosol delivery can provide therapeutic concentrations of drug in the lungs while minimizing the side effects associated with high systemic concentrations. In the case of lung transplantation, the drug is delivered directly to the airways, the location of the pathology resulting in most mortality in this population (chronic allograft rejection), maximizing the efficacy of this dose-dependent immunosuppressant.

World Transplant Congress. Boston, Massachusetts, USA, 22-27 July 2006

The World Transplant Congress (WTC) is the first joint international transplant meeting co-organised by the Transplantation Society, the American Society of Transplantation (AST) and the American Society of Transplant Surgeons (ASTS). It was the first meeting of this calibre that was being held by three world-renowned authorities in the field of transplantation. Under the direction of the congress president, AB Cosimi, the attendance of this meeting is a 'must' for all working in the field of transplantation. The congress had provided an important forum for the exchange of new scientific and clinical information that is relevant to solid organ and tissue transplantation. In addition, it also created an arena for the interchange of ideas regarding the care and management of transplant recipients. There were many sessions that were engineered in order to facilitate the discussion of socioeconomic, ethical and regulatory issues related transplantation. On the whole, the meeting has set a very high standard for any future transplant congresses to match-providing the delegates with updates on transplantation with the new scientific prospectives in T cell costimulation, innate immunity (dendritic cells), anatomy of immune response and regulatory T cell biology. More importantly, it has highlighted the potentials of harnessing these new findings for future biological therapies in preventing rejection and inducing tolerance.

Ciclosporin aerosol in lung transplantation

The development of ciclosporin as an aerosol for rejection immunosuppression following lung transplantation started as a research idea at the University of Pittsburgh in 1989. In the 17 subsequent years, the development of the aerosol, testing in animals and several protocols testing the drug in patients have all taken place at the University of Pittsburgh and State University of New York. No other medical advances have displaced the potential of the drug during this time in lung transplantation, which still has a dismal 5-year survival of 50%. Therefore, the recent publication of the double-blind, placebo-controlled study of aerosolised ciclosporin for long-term use to significantly improve patient survival was heralded as a breakthrough by the commentary in the New England Journal of Medicine. Nevertheless, multiple problems may prevent this drug from ever receiving FDA approval and reaching the market. These problems include the need for a multi-centre study, a lack of surrogate markers for chronic rejection in lung transplant patients and a drug formulation that will prevent the expansion of the use of aerosolised ciclosporin for other indications.

Advances in aerosols: adult respiratory disease

Recognition of the importance of breathing pattern in aerosol delivery and deposition has led to the design of devices that allow targeting of deposition to airways and alveoli. Systems incorporating patient feedback provide control of factors affecting deposition, and the control of dose to the lung can now be expected. New devices combined with a medical realization of therapeutic need are beginning to affect the range of drugs now available to the caregiver or in development for the immediate future. The interface between the patient and the device represents a new area of practical research. Facemasks have been shown to be important in terms of drug delivery with different behavior in metered dose inhaler (MDI)/valved holding chambers compared to nebulizers. Recently completed clinical trials have demonstrated the usefulness of therapy targeted to the lungs in reducing systemic toxicity with enhanced efficacy. A prime example is aerosolized cyclosporine, used to prevent rejection in lung transplantation. This agent has recently been shown to reduce mortality in transplant recipients and will lead to a new drug application in the United States. For larger patient populations, the pursuit of therapies to reduce the incidence of ventilator-associated pneumonia (VAP) can affect the outcome of illness in the intubated patient in the Intensive Care Unit (ICU). Patients with idiopathic pulmonary fibrosis (IPF) may benefit from high doses of aerosolized interferon gamma. Patient and caregiver safety are additional factors that will affect future approaches to therapy.

Lung transplantation in Australia: barriers to translating new evidence into clinical practice

Evidence "beyond reasonable doubt" may never be achievable for low-volume drugs.