Is there a role for cyclosporine in asthma?

[Strategic formulation study on dry powder inhalation system based on modulated molecular properties and controlled pharmacokinetics]

Cyclosporine A (CsA) has been widely used as an immunosuppressive agent, and recent outcomes from clinical studies are indicative of the potent therapeutic potential of CsA for chronic asthma and airway inflammation. The clinical use of CsA for airway inflammatory diseases is partly limited because of low oral bioavailability and severe systemic side effects. A number of CsA dosage forms have been proposed to overcome these drawbacks, for example, nebulizer formulation and metered-dose inhaler formulation for inhalation therapy, whereas these liquid formulations sometimes contain organic solvents and other solubilizers, leading to local irritant potency. In this context, our group developed a dry powder inhalation (DPI) system of CsA, employing a polymer-based amorphous solid dispersion (ASD) approach, for inhalation therapy on airway inflammations. There was marked improvement in dissolution behavior of the ASD formulation compared with that of an amorphous CsA. The new DPI system of CsA exhibited high dispersibility and suitable particle distribution for inhalation therapy. In vivo experiments demonstrated that inhaled DPI system of CsA attenuated inflammatory events in experimental asthma/chronic obstructive pulmonary disease (COPD) model rats as evidenced by a decrease of infiltrated granulocytes, and there was no excessive increase in systemic exposure of CsA at a pharmacologically effective dose, possibly leading to reduced systemic side effects. From these findings, combination use of CsA-loaded ASD and DPI systems might be a promising approach for the treatment of airway inflammatory diseases with improved pharmacodynamics and lower systemic exposure.

Development of cyclosporine A-loaded dry-emulsion formulation using highly purified glycerol monooleate for safe inhalation therapy

The main objective of this study was to improve the safety and oxidative stability of glycerol monooleate (GMO)-based dry-emulsion (DE) formulation containing cyclosporine A (CsA) for inhalation therapy. GMO or highly purified GMO (hpGMO) was used as surfactant for the DE formulations (GMO/DE or hpGMO/DE), the toxicological and physicochemical properties of which were characterized with a focus on oxidative stability, in vitro/in vivo toxicity, and dissolution property. Incubation of GMO at oxidation accelerating conditions for 10 days at 60°C resulted in the formation of lipid peroxides as evidenced by increased malondialdehyde (111 μmol/mg); however, hpGMO samples exhibited increase of only 20.7 μmol/mg in malondialdehyde level. No significant acute cytotoxicity was observed in rat alveolar L2 cells exposed to hpGMO (0.28mM), and intratracheal administration of hpGMO powder in rats did not cause an increase of the plasma LDH level. The hpGMO/DE exhibited marked improvement in dissolution behavior of CsA, and stable fine micelles with a mean diameter of 320 nm were formed when suspended in water. A respirable powder formulation of hpGMO/DE (hpGMO/DE-RP) was newly prepared, and its in vitro inhalation property and in vivo efficacy were also evaluated. The hpGMO/DE-RP exhibited high dispersibility in laser diffraction analysis and significantly improved potency to attenuate recruitment of inflammatory cells into airway and thickening of airway wall in an animal model. Thus, the strategic use of hpGMO would improve oxidative stability and local toxicity compared with a GMO-based DE formulation, and its application to RP formulation could be a promising approach for effective inhalation therapy.

Spray freeze-dried porous microparticles of a poorly water-soluble drug for respiratory delivery

Particles of poorly water-soluble drugs were prepared to develop a dry powder inhaler (DPI). Spray freeze-drying (SFD) technique using a four-fluid nozzle (4N), which has been developed by authors, was applied in this research. Ciclosporin and mannitol were used as a poorly water-soluble model drug and a dissolution-enhanced carrier, respectively. The organic solution of ciclosporin and aqueous solution of mannitol were separately and simultaneously atomized through the 4N, and the two solutions were collided with each other at the tip of the nozzle edge. The spray mists were immediately frozen in liquid nitrogen to form a suspension. Then, the iced droplets were freeze-dried to prepare the composite particles of the drug and carrier. tert-Butyl alcohol (t-BuOH) was used as the organic spray solvent due to its relatively high freezing point. The resultant composite particles with varying drug content were characterized depending on their morphological and physicochemical properties. The particles contained amorphous ciclosporin and δ-crystalline mannitol. The characteristic porous structure of SFD particles potentially contributed to their good aerodynamic performance. A series of particles with a similar size distribution and different drug content revealed that the incorporation of mannitol successfully improved the cohesive behavior of ciclosporin, leading to enhanced aerosol dispersion. The dissolution test method using low-volume medium was newly established to simulate the release process from particles deposited on the surface of the bronchus and pulmonary mucosa. The composite with hydrophilic mannitol dramatically improved the in vitro dissolution behavior of ciclosporin in combination with the porous structure of SFD particles.

Comparative studies on physicochemical stability of cyclosporine A-loaded amorphous solid dispersions

The present study aimed to evaluate the physical stability on amorphous solid dispersion (SD) of cyclosporine A (CsA) employing hydroxypropyl cellulose (HPC). SD formulations (5-30% CsA) of CsA such wet-milled SD (WM/SD) and freeze-dried SD (FD/SD) were prepared, and both SD formulations were stored at 40 °C/75% relative humidity for 8 weeks. Transitions in morphology, dissolution behavior, crystallinity and thermal behavior of CsA were evaluated. There was at least 84-fold improvement in initial dissolution rate of SD formulations compared with that of amorphous CsA powder, although their dissolution rate was gradually decreased under accelerated conditions. In particular, aged FD/SD with a drug load of 30% exhibited highly limited dissolution as evidenced by 40% reduction of solubility after 8 weeks of storage. In contrast, aged WM/SD exhibited less reduction in dissolution rate compared with FD/SD. No significant changes were seen in crystallinity and thermal behavior after aging of SD formulations for 8 weeks; however, electron microscopic observations revealed aggregation of drug molecules/particles in the aged FD/SD, possibly leading to the reduced dissolution. From these findings, stability on CsA-loaded SD might be variable depending on the preparation methodology, and the wet-milling approach could be a viable option for preparing efficacious SD formulations with improved stability.

Inhalable dry-emulsion formulation of cyclosporine A with improved anti-inflammatory effects in experimental asthma/COPD-model rats

The main purpose of the present study was to develop a novel respirable powder (RP) formulation of cyclosporine A (CsA) using a spray-dried O/W-emulsion (DE) system. DE formulation of CsA (DE/CsA) was prepared by spray-drying a mixture of erythritol and liquid O/W emulsion containing CsA, polyvinylpyrrolidone, and glyceryl monooleate as emulsifying agent. The DE/CsA powders were mixed with lactose carriers to obtain an RP formulation of DE/CsA (DE/CsA-RP), and its physicochemical, pharmacological, and pharmacokinetic properties were evaluated. Spray-dried DE/CsA exhibited significant improvement in dissolution behavior with ca. 4500-fold increase of dissolution rate, and then, nanoemulsified particles were reconstituted with a mean diameter of 317 nm. Laser diffraction analysis on the DE/CsA-RP suggested high dispersion of DE/CsA on the surface of the lactose carrier. Anti-inflammatory properties of the inhaled DE/CsA-RP were characterized in antigen-sensitized asthma/COPD-model rats, in which the DE/CsA-RP was more potent than the RP formulation of physical mixture containing CsA and erythritol in inhibiting inflammatory responses, possibly due to the improved dissolution behavior. Pharmacokinetic studies demonstrated that systemic exposure of CsA after intratracheal administration of the DE/CsA-RP at a pharmacologically effective dose (100 μg-CsA/rat) was 50-fold less than that of the oral CsA dosage form at a toxic dose (10 mg/kg). From these findings, use of inhalable DE formulation of CsA might be a promising approach for the treatment of airway inflammatory diseases with improved pharmacodynamics and lower systemic exposure.

In vitro and in vivo characterization on amorphous solid dispersion of cyclosporine A for inhalation therapy

Cyclosporine A (CsA) has been clinically used as immunosuppressant, and new application for airway inflammation was also proposed. However, the clinical use of CsA was limited due to severe adverse effects after systemic exposure and the poor solubility. In the present investigation, novel respirable powder (RP) of CsA was developed for pulmonary administration with use of solid dispersion of wet-milled CsA (WM/CsA), and the physicochemical and pharmacological properties of the WM/CsA and its RP formulation were characterized. CsA in the solid dispersion was found to be amorphous by X-ray powder diffraction and differential scanning calorimetry. It exhibited the improved dissolution behavior as compared to active pharmaceutical ingredients. Laser diffraction and cascade impactor analysis of newly developed WM/CsA-RP, consisting of jet-milled WM/CsA and lactose carriers, suggested high dispersion and deposition in the respiratory organs with the emitted dose and the fine particle fraction of 96 and 54%, respectively. Intratracheal administration of WM/CsA-RP (100 microg CsA) in experimental inflammatory rats led to 71 and 85% reduction of granulocyte recruitment in bronchoalveolar lavage fluids and lung tissues, respectively, with showing ca 10(2)-fold reduced AUC and C(max) values of plasma CsA as compared to the oral dosage form of CsA at toxic concentration (10 mg/kg). Upon these findings, WM/CsA-RP would be efficacious dosage form for clinical treatment of airway inflammations with minimal systemic side effects.

Immunomodulatory and biologic therapies for severe refractory asthma

Despite undoubted efficacy of the combination of inhaled corticosteroids and beta(2)-agonists for most asthmatic patients with moderate-to-severe disease, there remains approximately 10% of the asthmatic population with serious unremitting symptoms, resulting in considerable impact on quality of life, disproportionate use of health care resources, and adverse effects from regular systemic steroid use. In an ideal world, optimal treatment of severe refractory asthma should achieve the best possible asthma control and quality of life with the least dose of systemic corticosteroids. The choice and formulation of therapeutic agent are dictated by the severity of disease and may include immunological modifiers and biologic therapies. Unfortunately, current asthma guidelines offer little contribution to the management of the challenging patient with severe refractory asthma and none of them have addressed therapeutic alternatives to oral corticosteroids. This article reviews the current evidence for immunomodulating and biologic approaches in severe refractory asthma.

Additional evidence of acute anti-inflammatory effects of cyclosporin A in a murine model of pleurisy

INTRODUCTION

It is well known that cyclosporin A (CsA) exhibits important anti-inflammatory effects, besides its immunosuppressive activity. However, the mechanisms by which CsA exerts these effects remain unclear.

OBJECTIVE

This study evaluated whether the acute administration of CsA significantly interfered in leukocyte migration, exudation, myeloperoxidase (MPO) and adenosine-deaminase activities and nitrate/nitrite levels, in a mouse model of pleurisy.

MATERIALS AND METHODS

Pleurisy was induced by carrageenan (1%) treatment and the parameters were analyzed 4 and 48 h after. Groups of animals were previously treated with different doses of CsA and compared with non-treated groups.

RESULTS

CsA (0.1-5 mg/kg, intraperitoneal, 1 h before pleurisy induction) inhibited neutrophil migration (P<0.05), but not the exudation that occurred 4 h after pleurisy induction. At this time, CsA (1 mg/kg, 1 h before) also decreased nitrate/nitrite levels and MPO activity (P<0.01). CsA (2 mg/kg, 0.5 h before) was also effective in decreasing mononuclear influx, exudation and nitrate/nitrite levels 48 h after onset of inflammation.

CONCLUSIONS

These results indicate that the acute administration of CsA is able to reduce the two leukocyte populations that occur both at 4 and 48 h after pleurisy induction, late exudation (48 h), MPO activity (4 h) and nitrate/nitrite levels (4 and 48 h). Taken together, these findings indicate that CsA has acute anti-inflammatory effects in immunocompetent animals.

Effects of cyclosporin A administered into the airways against antigen-induced airway inflammation and hyperreactivity in the rat

The immunosuppressant cyclosporin A given orally has anti-asthma properties but carries an undesirable risk of systemic effects. We administered cyclosporin A to Brown Norway rats either orally (p.o.) or topically by intratracheal (i.t.) instillation into the airways before inhaled antigen. Cyclosporin A suppressed the antigen-induced accumulation of activated (CD25+) CD4+ T lymphocytes and eosinophils in the lung, interleukin-5 mRNA expression in lung tissue and airway hyperreactivity. Intratracheal cyclosporin A suppressed cell accumulation at a 10-fold lower dose than that required orally. Minimum effective doses were 3 mg x kg(-1) i.t. and 30 mg x kg(-1) p.o. Intratracheal administration reduced the plasma concentration and systemic exposure compared with an equieffective oral dose, but the reduction (4-5-fold) was not as large as anticipated. Our data suggests that although topical administration to asthmatics would provide some potential for an improved safety margin, it may not offer any major advantage over existing oral therapy. However, the data clearly demonstrate that a novel immunosuppressant with similar anti-inflammatory properties but reduced potential for systemic effects would offer an attractive therapy for severe asthma.

Cyclosporin as an oral corticosteroid sparing agent in stable asthma

BACKGROUND

Patients with chronic severe asthma are often dependent on the long term prescription of oral corticosteroids. The use of steroids is associated with serious side effects. Physicians treating such patients continue to search for alternative therapies that reduce the need for chronic dosing with oral steroids. Cyclosporin is an immunosuppressive agent and has benefits in the treatment of a number of inflammatory disorders. It has therefore been identified as an potentially useful agent in the treatment of chronic severe asthma both in terms of possible efficacy and as a steroid sparing agent.

OBJECTIVES

The objective of this review was to assess the effects of adding cyclosporin to oral steroids in the treatment of chronic steroid dependent asthmatics.

SEARCH STRATEGY

The Cochrane Airways Group trials register and reference lists of identified articles were searched.

SELECTION CRITERIA

Randomised trials looking at the addition of cyclosporin compared to placebo in adult steroid dependent asthmatics.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data extraction was carried out by two reviewers independently. Study authors were contacted for missing information.

MAIN RESULTS

Three trials fulfilled the criteria for inclusion in the review and a total of 106 patients were recruited into these studies. Data from 98 patients could be analysed. There was a small but significant treatment effect for cyclosporin in terms of steroid dose reduction (SMD -0.5, 95% CI -1.0, -0.04). No meta-analyses could be performed for measures of lung function although one study showed small, but significant improvements in lung spirometry.

REVIEWER'S CONCLUSIONS

The changes with cyclosporin are small and of questionable clinical significance. Given the side effects of cyclosporin, the evidence available does not recommend routine use of this drug in the treatment of oral corticosteroid dependent asthma.

Nebulizer-compatible liquid formulations for aerosol pulmonary delivery of hydrophobic drugs: glucocorticoids and cyclosporine

This review discusses pulmonary delivery of glucocorticoids and cyclosporine in pharmaceutically acceptable organic solvents and liposomes, as well as in micellar solutions and microemulsions, by means of liquid aerosols generated by nebulizers. The review points out the importance of a variety of parameters for successful treatment of immunologically mediated lung diseases by inhalation of drug containing aerosols with particular references to physico-chemical properties of formulations, aerosol parameters, pharmacokinetics, and lung deposition in experimental animals and humans. The prospects for the use of these types of formulations for clinical treatment of asthma, lung transplant rejection processes and other lung diseases are summarized.

New insights into the pathogenesis and management of steroid-resistant asthma

A population of difficult-to-control asthmatics exists who, despite high-dose daily GC therapy, continue to display evidence for active disease. This group has been termed steroid resistant since they fail to adequately respond to aggressive courses of high-dose oral and inhaled GC therapy. Persistent immune activation and airway inflammation which to varying degrees is resistant to GC therapy appears to define the immunological abnormality underlying SR asthma. Recent studies utilizing molecular biological techniques have identified both ligand- and DNA-binding defects that could possibly account for steroid resistance at a molecular level. The evaluation of the SR asthmatic must be comprehensive in its scope as several confounding factors can contribute to this symptom complex. Among others, these include poor compliance, improper medication technique, inadequate anti-inflammatory therapy, unrecognized contributing diseases, incorrect diagnoses, environmental factors, and psychosocial disturbances. The management of the SR asthmatic is challenging, and every attempt should be made to maximize conventional therapy in these patients prior to embarking on alternative therapies as all of the alternative anti-inflammatory/immunomodulatory modalities are associated with significant toxicity or cost. Second-generation inhaled GC therapy, methotrexate, cyclosporine, IVIG, and leukotriene antagonists are potential alternative therapies, and although they remain viable options, they have been used in small numbers, and for short periods of time, and fail to result in long-term remissions. Although much insight into the pathogenesis of SR asthma has been gained, several issues remain unresolved. Ongoing airway inflammation is thought to contribute to steroid resistance, but at present, we have no standard method of determining the degree of inflammation. The incorporation of bronchoscopy with transbronchial biopsy has the potential to provide the greatest amount of information regarding the presence or absence of ongoing airway inflammation, but the invasive nature of the procedure precludes its use in pediatric patients and the most severe adult asthmatics. Large multicenter, placebo-controlled studies evaluating the available alternative therapies that incorporate markers of airway inflammation are needed, as are studies that evaluate these therapies over longer periods of time. It is hoped that by better understanding the mechanisms involved and the natural history of the SR asthmatic, specific treatment modalities will be developed for this challenging group of severe asthmatics.

Amelioration of bleomycin-induced pulmonary injury by cyclosporin A

This study evaluated the effect of cyclosporin-A (CyA), a potent immunosuppressive drug, on Bleomycin (Bleo)-induced pulmonary inflammation in hamsters. Pulmonary injury was induced by a single intratracheal (i.t.) instillation of Bleo. Four groups of 10 male Syrian hamsters each received one of four treatments: (1) i.t. Bleo and daily intraperitoneal (i.p.) injections of CyA starting 1 day before i.t. instillation of Bleo (Bleo-CyA); (2) i.t. Bleo and i.p. injections of saline (Bleo-Sal); (3) i.t. saline and i.p. CyA (Sal-CyA); (4) i.t. saline and i.p. saline (Sal-Sal). Animals were sacrificed 14 days after i.t. treatment. Lung injury was evaluated histologically, biochemically, and by analysis of bronchoalveolar lavage (BAL) fluid. Treatment of hamsters with CyA significantly ameliorated the Bleo-induced lung injury, as determined by a semiquantitative morphological index that assesses the severity and extent of the injury on a scale of 0-3. Lung hydroxyproline measurements were lower in Bleo-CyA compared to Bleo-Sal, comparable to Sal-Sal and Sal-CyA controls. The percentage of neutrophils, eosinophils, and lymphocytes in BAL fluid was higher in Bleo-Sal and Bleo-CyA animals when compared with control Sal-CyA or Sal-Sal animals. A further increase in percentage of eosinophils was observed in Bleo-CyA compared with Bleo-Sal animals (13.3 +/- 6.6% [mean +/- SE] and 3.7 +/- 2.1%, respectively, p = .0007). BAL fluid protein content was higher in Bleo-Sal compared to Sal-Sal animals, but BAL fluid protein content from Bleo-CyA was not significantly different from that of Bleo-Sal animals. These results indicate that CyA ameliorates the Bleo-induced inflammation but does not prevent leakage of plasma protein or cells into the airspaces. The increased eosinophil numbers in Bleo-CyA-treated hamsters suggests enhanced production of interleukin-4 and -5.

The cyclosporins

This review presents the progress and some aspects achieved during recent years with cyclosporin sources, chemistry, biological activities, side effects, biosynthesis and metabolism. Although incomplete the results indicate future research trends and some white spots to be studied in the near future to afford unique insights into cell biology and to improve the search for similar and even more specific agents based on rational drug design.

The granulocyte-macrophage colony-stimulating factor/interleukin 3 locus is regulated by an inducible cyclosporin A-sensitive enhancer

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 3 (IL-3) are pleiotropic hemopoietic growth factors whose genes are closely linked and induced in T lymphocytes in a cyclosporin A (CsA)-sensitive fashion. Since we found that the human GM-CSF and IL-3 proximal promoters were not sufficient to account for the observed regulation of these genes, we mapped DNase I hypersensitive sites across the GM-CSF/IL-3 locus in the Jurkat human T-cell line to identify additional regulatory elements. We located an inducible DNase I hypersensitive site, 3 kb upstream of the GM-CSF gene, that functioned as a strong CsA-sensitive enhancer of both the GM-CSF and IL-3 promoters. Binding studies employing Jurkat cell nuclear extracts indicated that four sites within the enhancer associate with the inducible transcription factor AP1. Three of these AP1 elements lie within sequences that also associate with factors resembling the CsA-sensitive, T cell-specific transcription factor NFAT. We provide additional evidence suggesting that an AP1-like factor represents one of the components of NFAT. We propose that the intergenic enhancer described here is required for the correctly regulated activation of both GM-CSF and IL-3 gene expression in T cells and that it mediates the CsA sensitivity of the GM-CSF/IL-3 locus.

Allergy of the respiratory tract

The past year has seen significant advances in several fields of asthma and allergy research. Notable among these advances were the following: the demonstration that inflammatory granulocytes may be a source of cytokines; an increased understanding of the inter-relationships between the inflammatory cells invading the asthmatic bronchial mucosa; some important new approaches to asthma therapy; and the beginnings of a systematic classification of the structure of allergens and their antigenic epitopes.