Safety of inhaled corticosteroids: room for improvement

The medicinal chemistry evolution of antibody-drug conjugates

Antibody-drug conjugates (ADCs) comprise 3 components of wildly differing sizes: antibody (150 000 Da), linker (typically <500 Da) and payload (typically <500 Da). While the drug-linker makes up only a small percent of the ADC it has a disproportionately massive impact on all aspects of the ADC. Replacing maleimide with bromoacetamide (BrAc) affords stable attachment of the linker to the antibody cysteine, supports total flexibility for linker design and affords a more homogenous ADC. Optimisation of the protease cleavable dipeptide reduces aggregation, facilitates moderation of the physicochemical properties of the ADC and enables long-term stability to facilitate subcutaneous self-administration. Payloads are designed specifically to afford the optimal ADC. Structural information and SAR guide design to improve both potency and selectivity to the small molecule target improving the therapeutic index of resulting ADCs. Minimising the solvent exposed hydrophobic surface area improves the drug-like properties of the ADC, the realisation that the attachment heteroatom can be more than just the site for linker attachment as it can also drive potency and selectivity of the payload and the adoption of a prodrug strategy at project initiation are key areas that medicinal chemistry drives. For an optimal ADC the symbiotic relationship of the three structurally disparate components requires they all function in unison and medicinal chemistry has a huge role to ensure this happens.

Antibody drug conjugates beyond cytotoxic payloads

For many years, antibody drug conjugates (ADC) have teased with the promise of targeted payload delivery to diseased cells, embracing the targeting of the antibody to which a cytotoxic payload is conjugated. During the past decade this promise has started to be realised with the approval of more than a dozen ADCs for the treatment of various cancers. Of these ADCs, brentuximab vedotin really laid the foundations of a template for a successful ADC with lysosomal payload release from a cleavable dipeptide linker, measured DAR by conjugation to the Cys-Cys interchain bonds of the antibody and a cytotoxic payload. Using this ADC design model oncology has now expanded their repertoire of payloads to include non-cytotoxic compounds. These new payload classes have their origins in prior medicinal chemistry programmes aiming to design selective oral small molecule drugs. While this may not have been achieved, the resulting compounds provide excellent starting points for ADC programmes with some compounds amenable to immediate linker attachment while for others extensive SAR and structural information offer invaluable design insights. Many of these new oncology payload classes are of interest to other therapeutic areas facilitating rapid access to drug-linkers for exploration as non-oncology ADCs. Other therapeutic areas have also pursued unique payload classes with glucocorticoid receptor modulators (GRM) being the most clinically advanced in immunology. Here, ADC payloads come full circle, as oncology is now investigating GRM payloads for the treatment of cancer. This chapter aims to cover all these new ADC approaches while describing the medicinal chemistry origins of the new non-cytotoxic payloads.

Inhaled corticosteroids and risk of osteoporosis in late-middle-aged subjects: a multicenter European cohort study

BACKGROUND

Inhaled corticosteroids have been widely used for the regular treatment of asthma and chronic obstructive pulmonary diseases (COPD) over the past few decades. To date, studies investigating the effects of inhaled corticosteroids (ICS) on bone in populations including asthma and COPD patients, show conflicting results. The skeletal effects of ICS remain poorly understood. We assessed the association between ICS exposure and self-reported osteoporosis diagnosis in a European cohort study.

METHODS

The analysis was carried out by using clinical and questionnaire data available for subjects participating in the ECRHS III (European Community Respiratory Health Survey) with age >55 years.

RESULTS

Among the 3004 enrolled subjects, 245 were ICS users with an exposure ≥12 months. Osteoporosis was reported by 16 subjects in the ICS group (6.5%) and by 167 in the not exposed group (6.1%). The adjusted risk of osteoporosis in ICS users (≥12 months) was not greater in exposed subjects when compared with the unexposed ones (OR=1.02, 95CI%: 0.51, 2.03). The same result was observed even when considering in the analysis a longer exposure to the ICS use (≥36.5 months, the median ICS exposure for all subjects). History of COPD, use of oral corticosteroids, Body Mass Index, smoking and physical activity did not show any evidence of an association with osteoporosis.

CONCLUSIONS

Our study did not show any significant association between long- term ICS use and self-reported diagnosis of osteoporosis in subjects aged >55 years. To explore the real effect of ICS on bone status, further studies are needed, especially in the long-term ICS exposure.

Pharmacokinetic considerations surrounding triple therapy for uncontrolled asthma

INTRODUCTION

Solid pharmacological rationale and clinical evidence support the use of a combination of an inhaled corticosteroid (ICS), a long-acting β2-agonist, and a long-acting muscarinic antagonist in severe asthma, which clinically results in increased lung function, improved symptoms, and decreased exacerbation rates.

AREAS COVERED

We examined the pharmacokinetic issues associated with triple therapy for uncontrolled asthma. We considered the pharmacokinetic characteristics of the three drug classes, the role of inhalers in influencing their pharmacokinetic behavior, and the impact of severe asthma on the pharmacokinetics of inhaled drugs.

EXPERT OPINION

The pharmacokinetics of ICSs and bronchodilators are not affected to a great extent by severe asthma, according to a detailed review of the currently accessible literature. Compared to healthy people, patients with severe asthma show only minor variations in a few pharmacokinetic characteristics, which are unlikely to have therapeutic significance and do not require particular attention. However, the difficulty of obtaining pharmacokinetic profiles of the three drugs included in a triple therapy suggests that the clinical response should be followed over time, which can be considered a good surrogate indicator of whether the drugs have reached sufficient concentrations in the lung to exert a valid pharmacological action.

Inhaled Corticosteroids in Adults with Non-cystic Fibrosis Bronchiectasis: From Bench to Bedside. A Narrative Review

Due to their potent anti-inflammatory capacity (particularly in predominantly eosinophilic inflammation) and immunosuppressive properties, inhaled corticosteroids (ICSs) are widely used in asthmatic patients and also in individuals with chronic obstructive pulmonary disease (COPD) who suffer multiple exacerbations or have peripheral eosinophilia. However, there is little evidence for their use in non-cystic fibrosis bronchiectasis (hereafter, bronchiectasis). According to data extracted from large databases of bronchiectasis in adults, ICSs are used in more than 50% of patients without any scientific evidence to justify their efficacy and contrary to the recommendations of international guidelines on bronchiectasis that generally advise against their use. Indeed, bronchiectasis is a disease with predominantly neutrophilic inflammation and a high likelihood of chronic bacterial bronchial infection. Furthermore, it is known that due to their immunosuppressive properties, ICSs can induce an increase in bacterial infections. This manuscript aims to review the basic properties of ICSs, how they impact bronchiectasis in adults, the current position of international guidelines on this treatment, and the current indications and future challenges related to ICS use in bronchiectasis.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Circulating SSEA-1+ stem cell-mediated tissue repair in allergic airway inflammation

Structural changes known as airway remodeling characterize chronic/severe asthma and contribute to lung dysfunction. We previously reported that neonatal SSEA-1⁺ pulmonary stem/progenitor cells (PSCs) ameliorated airway inflammation in asthmatic mice. However, the molecular mechanisms by which endogenous SSEA-1⁺ PSC of adult mice afford beneficial effects in alveolar homeostasis and lung repair after allergen challenge remain incompletely understood. To analyze the expression profile and clarify the biological significance of endogenous adult lung SSEA-1⁺ cells in asthmatic mice. Lung SSEA-1⁺ cells and circulating SSEA-1⁺ cells in peripheral blood were determined by confocal microscopy and cytometric analysis. GFP chimeric mice were used to trace cell lineage in vivo. The roles of circulating SSEA-1⁺ cells were verified in ovalbumin-induced and house dust mite-induced allergic asthmatic models. In asthmatic mice, endogenous lung SSEA-1⁺ cells almost disappeared; however, a unique population of circulating SSEA-1⁺ cells was enriched after the challenge phase. In asthmatic mice, adoptive transfer of circulating SSEA-1⁺ cells had a specific homing preference for the lung in response to inhaled antigen through upregulating CXCR7–CXCL11 chemokine axis. Circulating SSEA-1⁺ cells can transdifferentiate in the alveolar space and ameliorate lung inflammation and structural damage through inhibiting the infiltration of inflammatory cells into peribronchovascular and goblet cell hyperplasia areas, reducing the thickened smooth muscle layers and PAS-positive mucus-containing goblet cells. Reinforcing bone marrow-derived circulating SSEA-1⁺ cells from peripheral blood into lung tissue which create a rescue mechanism in maintaining alveolar homeostasis and tissue repair to mediate lung protection for emergency responses after allergen challenge in asthmatic conditions.

Improving the risk-to-benefit ratio of inhaled corticosteroids through delivery and dose: current progress and future directions

INTRODUCTION

Inhaled corticosteroids (ICS) are known to increase the risk of systemic and local adverse effects, especially with high doses and long-term use. Hence, considerable resources are invested to improve pharmacokinetic/pharmacodynamic (PK/PD) properties of ICS, effective delivery systems and novel combination therapies to enhance the risk-to-benefit ratio of ICS.

AREAS COVERED

There is an unmet need for new solutions to achieve optimal clinical outcomes with minimal dose of ICS. This paper gives an overview of novel treatment strategies regarding the safety of ICS therapy on the basis of the three most recent molecules introduced to our everyday clinical practice - ciclesonide, mometasone furoate, and fluticasone furoate. Advances in aerosol devices and new areas of inhalation therapy are also discussed.

EXPERT OPINION

Current progress in improving the risk-to-benefit ratio of ICS through dose and delivery probably established pathways for further developments. This applies both to the improvement of the PK/PD properties of ICS molecules but also includes technical aspects that lead to simplified applicability of the device with simultaneous optimal drug deposition in the lungs. Indubitably, the future of medicine lies not only in the development of new molecules but also in technology and digital revolution.

Pharmacokinetic/pharmacodynamic approaches to drug delivery design for inhalation drugs

Introduction: Inhaled drugs are important in the treatment of many lung pathologies, but to be therapeutically effective they must reach unbound concentrations at their effect site in the lung that are adequate to interact with their pharmacodynamic properties (PD) and exert the pharmacological action over an appropriate dosing interval. Therefore, the evaluation of pharmacokinetic (PK)/PD relationship is critical to predict their possible therapeutic effect.Areas covered: We review the approaches used to assess the PK/PD relationship of the major classes of inhaled drugs that are prescribed to treat pulmonary pathologies.Expert opinion: There are still great difficulties in producing data on lung concentrations of inhaled drugs and interpreting them as to their ability to induce the desired therapeutic action. The structural complexity of the lungs, the multiplicity of processes involved simultaneously and the physical interactions between the lungs and drug make any PK/PD approach to drug delivery design for inhalation medications extremely challenging. New approaches/methods are increasing our understanding about what happens to inhaled drugs, but they are still not ready for regulatory purposes. Therefore, we must still rely on plasma concentrations based on the axiom that they reflect both the extent and the pattern of deposition within the lungs.

The risk of osteoporosis in patients with asthma

It is well-known that use of continuous systemic corticosteroids (SG) affects bone metabolism, bone mineral density (BMD), and ultimately increases the risk of osteoporosis. In patients with asthma, on the other hand, the effects of long-term high-dose inhaled corticosteroids (ICS) on BMD and risk of osteoporotic fractures is controversial. The reasons for this inconsistency could be explained by the fact that only few long-term studies investigating the effect of ICS in patients with asthma exist. The studies are characterized by different study designs and duration of ICS exposure, small study populations, and differences between the used ICS. The aim of this article is to unravel which factors, if any, that contribute to an increased risk of osteoporosis in patients with asthma and to summarize the evidence regarding adverse effects of ICS on bone metabolism, BMD and osteoporotic fractures in patients with asthma.

Relative efficacy and safety of inhaled corticosteroids in patients with asthma: Systematic review and network meta-analysis

BACKGROUND

Inhaled corticosteroids (ICSs) are recommended as first-line controller medications for persistent asthma. However, guidelines on the initial ICS doses, step-up and step-down algorithms, and when to switch to combination therapy vary.

OBJECTIVE

To understand the ideal starting doses of ICS therapy based on current evidence and to systematically compare low, moderate, and high starting doses of ICSs as monotherapy and in combination with long-acting β-agonists with respect to efficacy and safety.

METHODS

MEDLINE, Embase, and Cochrane databases were searched for relevant English-language articles published from 1980 to November 17, 2018. Randomized controlled trials with adult, steroid-naive, ICS-free (for ≥4 weeks) patients with asthma and a duration of 4 weeks or longer with an ICS treatment arm (monotherapy or combination therapy) were included. Separate fixed-effects Bayesian network meta-analyses were conducted on the extracted data for peak expiratory flow, forced expiratory volume in 1 second, nighttime rescue medication use, nighttime symptom score, and study withdrawal because of an adverse event.

RESULTS

A total of 31 randomized controlled trials were analyzed. All starting doses of ICSs were comparable with respect to nighttime rescue medication use, nighttime symptom score, change in forced expiratory volume in 1 second, and study withdrawal because of an adverse event. Significant improvement in morning peak expiratory flow was observed with high-dose ICSs and with low- and moderate-dose ICSs and long-acting β-agonists than with low-dose ICSs.

CONCLUSION

Overall, a high starting dose of ICSs had no additional clinical benefit in 3 of the 4 efficacy parameters compared with low or moderate ICS doses for controlling moderate to severe asthma but might have potential safety concerns.

Erythrocytes as Carriers: From Drug Delivery to Biosensors

Drug delivery using natural biological carriers, especially erythrocytes, is a rapidly developing field. Such erythrocytes can act as carriers that prolong the drug's action due to its gradual release from the carrier; as bioreactors with encapsulated enzymes performing the necessary reactions, while remaining inaccessible to the immune system and plasma proteases; or as a tool for targeted drug delivery to target organs, primarily to cells of the reticuloendothelial system, liver and spleen. To date, erythrocytes have been studied as carriers for a wide range of drugs, such as enzymes, antibiotics, anti-inflammatory, antiviral drugs, etc., and for diagnostic purposes (e.g. magnetic resonance imaging). The review focuses only on drugs loaded inside erythrocytes, defines the main lines of research for erythrocytes with bioactive substances, as well as the advantages and limitations of their application. Particular attention is paid to in vivo studies, opening-up the potential for the clinical use of drugs encapsulated into erythrocytes.

Pharmacokinetics and pharmacodynamics of inhaled corticosteroids for asthma treatment

The differences in the pharmacokinetic (PK) characteristics of inhaled corticosteroids (ICSs) critically influence the profile of each of them, but also the significant differences in glucocorticoid receptor selectivity, potency, and physicochemical properties are critical in defining the pharmacodynamic (PD) profile of an ICS. The PK and PD properties of ICSs used in asthma and the importance of their interrelationship have been reviewed. The differences among the ICSs in PK and PD must be considered when an ICS should be prescribed to an asthmatic patient because a better understanding of the PK/PD interrelationship of ICSs could be important to better fit with the between-patient variability and within-patient repeatability in the response to ICSs that often complicate the therapeutic approach to the asthmatic patient. The role of the device in influencing the PK profile of an ICS must be always considered because it is crucial. Also patient-related factors and disease severity affect pulmonary deposition of ICS.

Autologous Red Blood Cell Delivery of Betamethasone Phosphate Sodium for Long Anti-Inflammation

Although glucocorticoids are highly effective in treating various types of inflammation such as skin disease, rheumatic disease, and allergic disease, their application have been seriously limited for their high incidence of side effects, particularly in long term treatment. To improve efficacy and reduce side effects, we encapsulated betamethasone phosphate (BSP) into biocompatible red blood cells (RBCs) and explored its long acting-effect. BSP was loaded into rat autologous erythrocytes by hypotonic preswelling method, and the loading amount was about 2.5 mg/mL cells. In vitro, BSP loaded RBCs (BSP-RBCs) presented similar morphology, osmotic fragility to native RBCs (NRBCs). After the loading process, the loaded cells can maintain around 70% of Na⁺/K⁺-ATPase activity of natural cells. In vivo, a series of tests including survival, pharmacokinetics, and anti-inflammatory effect were carried out to examine the long-acting effect of BSP-RBCs. The results shown that the loaded cells could circulate in plasma for over nine days, the release of BSP can last for over seven days and the anti-inflammatory effect can still be observed on day 5 after injection. Totally, BSP-loaded autologous erythrocytes seem to be a promising sustained releasing delivery system with long anti-inflammatory effect.

Measuring safety of inhaled corticosteroids in asthma

BACKGROUND

Despite evidence demonstrating generally excellent therapeutic ratios for inhaled corticosteroids (ICSs) in asthma treatment, many clinicians and patients have ongoing concerns regarding their safety. To frame discussions of ICS safety, it is important to understand how safety is measured.

OBJECTIVE

To discuss how ICS safety is and should be measured.

METHODS

Discussion is augmented by relevant articles from the literature.

RESULTS

The therapeutic value of corticosteroids depends on the activation and repression of thousands of genes. However, it is not fully known which genes cause the desirable, therapeutic effects and which cause the adverse effects. The drug development process attempts to elucidate the clinically significant therapeutic effects and adverse effects of a candidate molecule and then compare them to those of currently available corticosteroids. Approaches to monitoring safety include clinical trials, retrospective comparison to historical efficacy and safety data, surrogate markers, animal models, and in vitro assays. Both preclinical and clinical data are used to compare safety among corticosteroids; however, no specific pathway or model that can robustly predict therapeutic ratios has been identified. Furthermore, variation in adverse effects is influenced by isoforms of the glucocorticoid receptor, differences in corticosteroid characteristics, differences among patients, and environmental variation.

CONCLUSION

Although some preclinical and patient-based metrics have predictive value, there is a clear need for improved biomarkers of corticosteroid adverse effects. Integrated analysis of preclinical and clinical data, including long-term safety data, could be used to address this important unmet need.

Bone mineral density and fracture risk with long-term use of inhaled corticosteroids in patients with asthma: systematic review and meta-analysis

OBJECTIVES

We aimed to assess the association between long-term use of inhaled corticosteroids (ICS) and bone adverse effects in patients with asthma.

DESIGN

Systematic review and meta-analysis of fracture risk and changes in bone mineral density with long-term ICS use in asthma.

METHODS

We initially searched MEDLINE and EMBASE in July 2013, and performed an updated PubMed search in December 2014. We selected randomised controlled trials (RCTs) and controlled observational studies of any ICS (duration at least 12 months) compared to non-ICS use in patients with asthma. We conducted meta-analysis of ORs for fractures, and mean differences in bone mineral density. Heterogeneity was assessed using the I(2) statistic.

RESULTS

We included 18 studies (7 RCTs and 11 observational studies) in the systematic review. Meta-analysis of observational studies did not demonstrate any significant association between ICS and fractures in children (pooled OR 1.02, 95% CI 0.94 to 1.10, two studies), or adults (pooled OR 1.09, 95% CI 0.45 to 2.62, four studies). Three RCTs and three observational studies in children reported on bone mineral density at the lumbar spine, and our meta-analysis did not show significant reductions with ICS use. Three RCTs and four observational studies in adults reported on ICS use and bone mineral density at the lumbar spine and femur, with no significant reductions found in the meta-analysis compared to control.

CONCLUSIONS

ICS use for ≥12 months in adults or children with asthma was not significantly associated with harmful effects on fractures or bone mineral density.

Pharmacotherapy of critical asthma syndrome: current and emerging therapies

The critical asthma syndrome (CAS) encompasses the most severe, persistent, refractory asthma patients for the clinician to manage. Personalized pharmacotherapy is necessary to prevent the next acute severe asthma exacerbation, not just the control of symptoms. The 2007 National Asthma Education and Prevention Program Expert Panel 3 provides guidelines for the treatment of uncontrolled asthma. The patient's response to recommended pharmacotherapy is highly variable which risks poor asthma control leading to frequent exacerbations that can deteriorate into CAS. Controlling asthma symptoms and preventing acute exacerbations may be two separate clinical activities with their own unique demands. Clinicians must be prepared to use the entire spectrum of asthma medications available but must concurrently be aware of potential drug toxicities some of which can paradoxically worsen asthma control. Medications normally prescribed for COPD can potentially be useful in the CAS patient, particularly those with asthma-COPD overlap syndrome. Immunomodulation with drugs like omalizumab in IgE-mediated asthma syndromes is one important approach. New and emerging drugs address unique aspects of airway inflammation and biology but at a significant financial cost. The pharmacology and toxicities of the agents that may be used in the treatment of CAS to control asthma symptoms and prevent severe exacerbations are reviewed.

The acute management of asthma

Patients presenting to the emergency department (ED) or clinic with acute exacerbation of asthma (AEA) can be very challenging varying in both severity and response to therapy. High-dose, frequent or continuous nebulized short-acting beta2 agonist (SABA) therapy that can be combined with a short-acting muscarinic antagonist (SAMA) is the backbone of treatment. When patients do not rapidly clinically respond to SABA/SAMA inhalation, the early use of oral or parenteral corticosteroids should be considered and has been shown to impact the immediate need for ICU admission or even the need for hospital admission. Adjunctive therapies such as the use of intravenous magnesium and helium/oxygen combination gas for inhalation and for driving a nebulizer to deliver a SABA and or SAMA should be considered and are best used early in the treatment plan if they are likely to impact the patients' clinical course. The use of other agents such as theophylline, leukotriene modifiers, inhaled corticosteroids, long-acting beta2 agonist, and long-acting muscarinic antagonist currently does not play a major role in the immediate treatment of AEA in the clinic or the ED but is an important therapeutic option for physicians to be aware of and to consider initiating at the time of discharge from clinic, hospital, or ED to reduce later clinical worsening and readmission to the ED and hospital. A comprehensive summary is provided of the currently available respiratory pharmaceuticals approved for asthma and other airway syndromes. Clinicians must be prepared to use the entire spectrum of medications available for the treatment of acute asthma exacerbations and the agents that should be initiated to prevent worsening or additional exacerbations. They need to be familiar with the major potential drug toxicities associated with their use.

Novel glucocorticoid receptor agonists in the treatment of asthma

INTRODUCTION

Inhaled corticosteroids are the only drugs that effectively suppress the airway inflammation, but they can induce considerable systemic and adverse effects when they are administered chronically at high doses. Consequently, the pharmaceutical industry is still searching for newer entities with an improved therapeutic index.

AREAS COVERED

Herein, the authors review the research in the glucocorticoid field to identify ligands of the glucocorticoid receptor (GR). These ligands preferentially induce transrepression with little or no transactivating activity, in order to have a potent anti-inflammatory action and a low side-effects profile.

EXPERT OPINION

Several agents have been synthesized, but few have been tested in experimental models of asthma. Furthermore, only three (BI-54903, GW870086X and AZD5423) have entered clinical development, although the development of at least one of them (BI-54903) was discontinued. The reason for the limited success so far obtained is that the model of transactivation versus transrepression is a too simplistic representation of GR activity. It is difficult to uncouple the therapeutic and harmful effects mediated by GR, but some useful information that might change the current perspective is appearing in the literature. The generation of gene expression 'fingerprints' produced by different GR agonists in target and off-target human tissues could be useful in identifying drug candidates with an improved therapeutic ratio.

Impact of Inhaled Corticosteroids on Growth in Children with Asthma: Systematic Review and Meta-Analysis

Background

Long-term inhaled corticosteroids (ICS) may reduce growth velocity and final height of children with asthma. We aimed to evaluate the association between ICS use of >12 months and growth.

Methods

We initially searched MEDLINE and EMBASE in July 2013, followed by a PubMed search updated to December 2014. We selected RCTs and controlled observational studies of ICS use in patients with asthma. We conducted random effects meta-analysis of mean differences in growth velocity (cm/year) or final height (cm) between groups. Heterogeneity was assessed using the I² statistic.

Results

We found 23 relevant studies (twenty RCTs and three observational studies) after screening 1882 hits. Meta-analysis of 16 RCTs showed that ICS use significantly reduced growth velocity at one year follow-up (mean difference -0.48 cm/year (95% CI -0.66 to -0.29)). There was evidence of a dose-response effect in three RCTs. Final adult height showed a mean reduction of -1.20 cm (95% CI -1.90 cm to -0.50 cm) with budesonide versus placebo in a high quality RCT. Meta-analysis of two lower quality observational studies revealed uncertainty in the association between ICS use and final adult height, pooled mean difference -0.85 cm (95% CI -3.35 to 1.65).

Conclusion

Use of ICS for >12 months in children with asthma has a limited impact on annual growth velocity. In ICS users, there is a slight reduction of about a centimeter in final adult height, which when interpreted in the context of average adult height in England (175 cm for men and 161 cm for women), represents a 0.7% reduction compared to non-ICS users.

Differences in the efficacy and safety among inhaled corticosteroids (ICS)/long-acting beta2-agonists (LABA) combinations in the treatment of chronic obstructive pulmonary disease (COPD): Role of ICS

Inhaled corticosteroids (ICS) are frequently recommended for the treatment of asthma and COPD, often in combination with long-acting beta2-agonists (LABA), depending on the severity of the disease and/or on the specific phenotype. Several ICS/LABA combinations are currently available that differ in their pharmacokinetic characteristics and dose of both components. Thus, this review assesses differences in the efficacy and the safety profiles of the ICS components in the two more frequently used ICS/LABA combinations (budesonide/formoterol and fluticasone/salmeterol) for the management of COPD. Whereas the basic mechanism of action is similar for all ICS (binding with the intracellular glucocorticoid receptor, which mediates both genomic and non genomic effects), the pharmacokinetic and characteristics of ICS are quite different in terms of receptor affinity, bioavailability, lipophilicity and drug persistence in the airways. Fluticasone persists longer in airway mucus and requires more time to dissolve in the lining fluid and then enter the airway wall, whereas budesonide is cleared more quickly from the airways. Comparative efficacy of the two major ICS/LABA combinations recommended for the treatment of COPD show similar efficacy in terms of reduction of exacerbations, improvement in forced expiratory volume in the first second (FEV1) and quality of life. One retrospective cohort study suggested a greater efficacy for the budesonide/formoterol combination on hospital or emergency department admissions, oral corticosteroid courses, and addition of tiotropium, and an observational real-life study reported a greater reduction of COPD exacerbations with budesonide/formoterol than with fluticasom/salmeterol combination. Among the potential side effects of chronic ICS treatment in patients with COPD, recently the use of fluticasone or fluticasone/salmeterol combination has been associated with a higher prevalence of pneumonia in the major long-term studies. On the other hand, no similar increased risk of pneumonia has been reported in patients with COPD treated with the budesonide/formoterol combination. A recent population-based cohort study from the Quebec database showed that the adjusted odds ratio for having severe pneumonia was higher for fluticasone (2.1) than for budesonide (1.17) or other ICS (1.41). Of the ICS studied, only fluticasone demonstrated a dose-related increase in risk of pneumonia in patients with COPD. This difference between fluticasone and budesonide may be explained by the longer retention of fluticasone in the airways, with potentially greater inhibition of type-1 innate immunity. Therefore, the risk:benefit ratio should be evaluated thoroughly when choosing an ICS/LABA combination for patients with COPD.

Inhaled corticosteroids in children: effects on bone mineral density and growth

Potent, topically active corticosteroids with minimum systemic activity have fewer adverse effects than do systemic corticosteroids, and can control both asthma and allergic rhinitis when given in recommended doses. However, study findings show that children with asthma receiving budesonide and beclometasone dipropionate have decreased linear growth, and that children who receive long-term inhaled corticosteroid therapy for asthma have height deficits 1-2 years after treatment initiation that persist into adulthood. The effects of inhaled corticosteroids on growth seem to be dependent on both dose and duration; the degree of systemic effects is dependent on pharmacokinetic properties (ie, absorption, distribution, and elimination), whereas the effective dose delivered is dependent on the delivery system and potency of the molecule. The effects of corticosteroids on bone mineral density in children seem to be more amenable to intervention; long-term therapy with inhaled corticosteroid therapy is safer than frequent bursts of oral corticosteroids on bone mineral accretion in this regard. Importantly, adequate nutrition (particularly sufficient intake of calcium and vitamin D) should prevent or blunt the effects of corticosteroids on bone mineral density. The potential adverse effects of inhaled corticosteroids need to be weighed against the large and well established benefit of these drugs to control persistent asthma. To minimise any adverse effects, treatment with inhaled corticosteroids should always aim to reach the lowest effective dose that gives the patient good asthma control.

Effect of inhaled corticosteroids on glycemic status

Although the dysglycemic effects of systemic glucocorticoid therapy are well known, the effect of inhaled corticosteroids (ICS) on carbohydrate metabolism is still a subject of debate. The systemic bioavailability of ICS is claimed to be minimal and the side effects negligible. However, some large retrospective cohort studies showed a definite association between ICS use and incident diabetes or worsening glycemic control in pre-existing diabetes. There are no professional-body recommended guidelines on the diagnosis and management of steroid-induced diabetes for the general population. This review aims to evaluate the systemic dysglycemic effect of ICS treatment and to propose a management algorithm.

Inhaled corticosteroids for asthma: on-demand or continuous use

Continuous inhaled corticosteroid treatment is highly effective in children and adults with mild persistent asthma, although some therapeutic benefits are not lost if treatment is delayed. Many patients do not adhere to continuous treatment with inhaled corticosteroids, but rather take them intermittently, usually at the time of increased symptoms. Based on these observations it has been proposed that for patients with mild persistent asthma inhaled corticosteroids should be used on-demand when symptoms are troublesome, rather than on a continuous basis. The article reviews the pharmacological properties of inhaled corticosteroids used in clinical trials of on-demand treatment, as well as the evidence for the efficacy and safety of on-demand compared with continuous inhaled corticosteroid treatment of mild persistent asthma in adults and children. The place of on-demand treatment with inhaled corticosteroids in the management of asthma is discussed, as well as future directions for different management strategies for this group.

Inhaled corticosteroids in lung diseases

Inhaled corticosteroids (ICSs) are used extensively in the treatment of asthma and chronic obstructive pulmonary disease (COPD) due to their broad antiinflammatory effects. They improve lung function, symptoms, and quality of life and reduce exacerbations in both conditions but do not alter the progression of disease. They decrease mortality in asthma but not COPD. The available ICSs vary in their therapeutic index and potency. Although ICSs are used in all age groups, younger and smaller children may be at a greater risk for adverse systemic effects because they can receive higher mg/kg doses of ICSs compared with older children. Most of the benefit from ICSs occurs in the low to medium dose range. Minimal additional improvement is seen with higher doses, although some patients may benefit from higher doses. Although ICSs are the preferred agents for managing persistent asthma in all ages, their benefit in COPD is more controversial. When used appropriately, ICSs have few adverse events at low to medium doses, but risk increases with high-dose ICSs. Although several new drugs are being developed and evaluated, it is unlikely that any of these new medications will replace ICSs as the preferred initial long-term controller therapy for asthma, but more effective initial controller therapy could be developed for COPD.

Therapeutic options for severe asthma

As the overall prevalence of asthma has escalated in the past decades, so has the population of patients with severe asthma. This condition is often difficult to manage due to the relative limitation of effective therapeutic options for the physician and the social and economic burden of the disease on the patient. Management should include an evaluation and elimination of modifiable risk factors such as smoking, allergen exposure, obesity and non-adherence, as well as therapy for co-morbidities like gastro-esophageal reflux disease and obstructive sleep apnea. Current treatment options include conventional agents such as inhalational corticosteroids, long acting β(2) agonists, leukotriene antagonists, and oral corticosteroids. Less conventional treatment options include immunotherapy with methotrexate, cyclosporine and tacrolimus, biological drugs like monoclonal antibodies, tumor necrosis factor-α blockers and oligonucleotides, phosphodiesterase inhibitors, antimicrobials and bronchial thermoplasty.

Complementary anti-inflammatory effects of a β-blocker and a corticosteroid in an asthma model

Glucocorticosteroids are the mainstay treatment for chronic asthma; however, adverse effects can limit their usefulness. We previously determined in experimental asthma that chronic administration of β₂-adrenoceptor inverse agonists reduced airway hyperresponsiveness and indexes of inflammation. However, the effect of co-administration of glucocorticosteroids with β₂-adrenoceptor inverse agonists is unknown. Therefore, we evaluated the anti-inflammatory effect of co-administration of dexamethasone, a glucocorticosteroid, and nadolol, a β₂-inverse agonist, in a murine asthma model. We measured eosinophils and cytokines in bronchoalveolar lavage fluid and mucin content in epithelial cells after exposure to different concentrations of dexamethasone and nadolol. Dexamethasone was administered for 3 days and nadolol for 24 days prior to ovalbumin challenge. Both drugs were continued during five daily intranasal challenges with ovalbumin. Independent administration of dexamethasone (0.4 mg/kg/day) or nadolol (25 ppm) reduced bronchoalveolar lavage eosinophils by 58% and 36%, respectively (P < 0.05). Co-administration of both drugs yielded an additive reduction in eosinophils (81%, P < 0.05). Co-administration of both drugs (dexamethasone 0.4 mg/kg/day and nadolol 25 ppm) also yielded a greater reduction in mucin volume density (83%) than either drug alone (18% for dexamethasone and 62% for nadolol) and greater than high-dose dexamethasone (71%) alone (P < 0.05). Similarly, co-administration of both drugs (dexamethasone 0.4 mg/kg/day and nadolol 25 ppm) yielded an additive effect on the reduction of type 2 cytokines in bronchoalveolar lavage fluid equivalent to the administration of a 10-fold higher dose of dexamethasone. In Summary, the simultaneous administration of a glucocorticosteroid and a β₂-adrenoceptor inverse agonist was more effective at reducing indexes of airway inflammation than either drug given alone; suggesting nadolol may possess "glucocorticoid-sparing" properties.

Inhaled corticosteroids should be the first line of treatment for children with asthma

Although montelukast is claimed to be preferable to inhaled corticosteroids in children with asthma and allergic rhinitis, virus-induced exacerbations, exercise induced asthma, and in those experiencing difficulties with inhalation therapy, there is no scientific evidence to support any of these claims. In comparative trials and systematic reviews, inhaled corticosteroids are clearly more effective than montelukast in reducing asthma exacerbations, improving lung function, symptom scores, and rescue medication use. The effects on exercise induced bronchoconstriction appear to be similar. Because of their superior efficacy and excellent long-term efficacy and safety profile, inhaled corticosteroids are the treatment of first choice for the maintenance therapy of childhood asthma, irrespective of age or clinical phenotype.

Ciclesonide modulates in vitro allergen-driven activation of blood mononuclear cells and allergen-specific T-cell blasts

BACKGROUND

Ciclesonide, an inhaled corticosteroid with almost no affinity for the glucocorticoid receptor, is highly effective in downregulating in vitro pro-inflammatory activities of airway parenchymal cells when converted into the active metabolite desisobutyryl-ciclesonide.

OBJECTIVE

We evaluate whether ciclesonide could effectively downregulate also antigen- or allergen-induced activation of peripheral blood mononuclear cell and of allergen-specific T-cell blasts.

METHODS

Peripheral blood mononuclear cells were isolated from non atopic and atopic asthmatic children sensitized to Phleum pratense (PhlP5). Proliferation toward Candida albicans or PhlP5 in the presence of ciclesonide or desisobutyryl-ciclesonide (0.003-3.0 μM) was evaluated as [(3)H]thymidine incorporation. Modulation of PhlP5-specific T-cell blasts proliferation and PhlP5-induced interleukin 4 expression by ciclesonide and desisobutyryl-ciclesonide were measured.

RESULTS

Peripheral blood mononuclear cell proliferation to C. albicans was dose-dependently inhibited by 0.3-3.0 μM ciclesonide and desisobutyryl-ciclesonide but inhibition by desisobutyryl-ciclesonide was higher. A significant proliferation to PhlP5 was observed only in cultures from atopic subjects: an effective downregulation was already detected at 0.03 μM ciclesonide and 0.003 μM desisobutyryl-ciclesonide (complete inhibition at 3 μM ciclesonide and 0.03 μM desisobutyryl-ciclesonide). 3 μM ciclesonide and desisobutyryl-ciclesonide reduced the PhlP5-specific T-cell blast proliferation and interleukin 4-producing cell proportion.

CONCLUSIONS AND CLINICAL RELEVANCE

These in vitro data, obtained at concentrations similar to those reached in vivo at bronchial level, are in favor of an efficient inhibition of ciclesonide on the T-cell mediated response toward allergens. Additional studies are required to confirm these preliminary data on the reduced activity of the drug on allergen-specific T-cell blast activation that may have clinical relevance.

Ciclesonide in wheezy preschool children with a positive asthma predictive index or atopy

BACKGROUND

Few large-scale studies have examined inhaled corticosteroid treatment in preschool children with recurrent wheeze. We assessed the effects of ciclesonide in preschool children with recurrent wheeze.

METHODS

We included children 2-6 yrs with recurrent wheeze and a positive asthma predictive index or aeroallergen sensitization to, excluding patients with episodic viral wheezing. After a 2-4-week baseline period, patients with ongoing symptoms or rescue medication use were randomised to once-daily ciclesonide 40, 80, 160 μg or placebo for 24 weeks.

RESULTS

The number of wheeze exacerbations requiring systemic corticosteroids was unexpectedly low in all groups: 25 (10.2%) in placebo group, as compared to 11 (4.4%), 18 (7.3%), and 17 (6.7%) in ciclesonide 40, 80, and 160 μg, respectively. The difference in time to first exacerbation was not significantly different between groups (p = 0.786), but the difference in exacerbation rates between placebo and the pooled ciclesonide groups was (p = 0.03). Large and significant (p < 0.0001) improvements in symptom scores and rescue medication use occurred in all groups, including placebo. Improvements in FEV(1) and FEF(25-75) (measured in 284 4-6 yr olds) were larger in the ciclesonide than in the placebo group. No differences in safety parameters (adverse events, height growth, serum and urinary cortisol levels) between ciclesonide and placebo were observed.

CONCLUSIONS

In preschool children with recurrent wheeze and a positive asthma predictive index, ciclesonide modestly reduces wheeze exacerbation rates and improves lung function. A large placebo response and unexpected selection of patients with mild disease may have affected outcomes, highlighting the heterogeneity of preschool wheezing disorders.

Conjugated linoleic acid (CLA): is it time to supplement asthma therapy?

The limitations and side effects of existing asthma therapies prompt interest in complementary and alternative therapies. Conjugated linoleic acids (CLA) are a family of natural fatty acids found primarily in beef and dairy products. These molecules have a variety of biological properties which suggest potential benefit in asthma, including effects on energy regulation, lipid metabolism, inflammation and immune function. Here we review the evidence for these effects from pre-clinical and clinical studies, their significance in the context of human asthma, and discuss the potential role for CLA supplementation in asthma management.

Long-term use of fluticasone propionate/salmeterol fixed-dose combination and incidence of nonvertebral fractures among patients with COPD in the UK General Practice Research Database

INTRODUCTION

There has been inconsistent evidence on the association between use of inhaled corticosteroids (ICS) and increased risk of nonvertebral fractures in patients with asthma or chronic obstructive pulmonary disease (COPD). In a large population-based study in the United Kingdom, we estimated the association between fluticasone propionate/salmeterol fixed-dose combination (FSC) and other ICS use and nonvertebral fracture incidence among patients with COPD.

METHODS

We identified a cohort of patients aged ≥ 45 years with COPD in the General Practice Research Database (GPRD) between 2003 and 2006. We used a nested case-control design to estimate the odds of incident nonvertebral fractures associated with prior prescriptions of FSC and other ICS, applying conditional logistic regression and controlling for potential confounders. Exposure to FSC and other ICS was assessed by recency, duration, and number of prescriptions. Average daily dose was defined as low, medium, high, or very high using fluticasone propionate equivalents.

RESULTS

We identified 1523 nonvertebral fracture cases among 53 191 patients with COPD at risk in the cohort. Use of FSC in the year prior to the index date was associated with a statistically significant increase in the odds of nonvertebral fractures (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.07-1.47); however, there was no increase in the odds of nonvertebral fractures for other ICS use (OR, 1.12; 95% CI, 0.97-1.30). When examining results by the recent use of prescriptions, an exposure that occurred farther from the index date was associated with a significant increase in nonvertebral fracture (26-52 days prior OR, 1.36; 95% CI, 1.04-1.77; 53-365 days prior OR, 1.39; 95% CI, 1.07-1.78), whereas categories of more recent use (0-12 days prior or 13-25 days prior) were not associated with nonvertebral fractures relative to no FSC use. No pattern of association between increasing levels of FSC or other ICS average daily dose and increased odds of nonvertebral fracture was observed.

CONCLUSION

We did not observe a consistent association between prescriptions of FSC or other ICS in terms of recent use or average daily dose in the prior year and increases in the odds of nonvertebral fractures in patients with COPD, although ever use of FSC was associated with a slight elevation in the odds.

Long-term therapy in COPD: any evidence of adverse effect on bone?

Patients with COPD have high risk for osteoporosis and fractures. Hip and vertebral fractures might impair mobility, and vertebral fractures further reduce lung function. This review discusses the evidence of bone loss due to medical treatment opposed to disease severity and risk factors for COPD, and therapeutic options for the prevention and treatment of osteoporosis in these patients. A review of the English-language literature was conducted using the MEDLINE database until June 2009. Currently used bronchodilators probably lack adverse effect on bone. Oral corticosteroids (OCS) increase bone resorption and decrease bone formation in a dose response relationship, but the fracture risk is increased more than reflected by bone densitometry. Inhaled corticosteroids (ICS) have been associated with both increased bone loss and fracture risk. This might be a result of confounding by disease severity, but high doses of ICS have similar effects as equipotent doses of OCS. The life-style factors should be modified, use of regular OCS avoided and use of ICS restricted to those with evidenced effect and probably kept at moderate doses. The health care should actively reveal risk factors, include bone densitometry in fracture risk evaluation, and give adequate prevention and treatment for osteoporosis.

Montelukast as an alternative to low-dose inhaled corticosteroids in the management of mild asthma (the SIMPLE trial): an open-label effectiveness trial

OBJECTIVE

To evaluate the effectiveness of montelukast as monotherapy for patients with mild asthma who remain uncontrolled or unsatisfied while on inhaled corticosteroid (ICS) monotherapy.

DESIGN

A multicentre, open-label study. Patients (six years of age or older) had ICS therapy discontinued and were treated with orally administered montelukast once daily for six weeks.

MAIN OUTCOME MEASURES

The primary outcome measure was the rate at which asthma symptom control was achieved or maintained after six weeks of treatment. The secondary outcome measures were to compare compliance and physician satisfaction, and to further assess the safety and tolerability of montelukast.

RESULTS

Of the 534 patients enrolled, 481 (90.1%) completed the study. Mean (+/- SD) age was 27.8+/-19.0 years. The number of patients with uncontrolled symptoms decreased from 455 (85.2%) at baseline to 143 (26.8%) at week 6 (P<0.001), and mean Asthma Control Questionnaire score decreased from 1.4+/-0.8 to 0.6+/-0.6 (P<0.001), representing a clinically significant improvement. Of the 79 patients with controlled asthma symptoms at baseline, 73.4% maintained asthma control at week 6. Compliance to asthma therapy increased from 41% at baseline for ICS to 88% at week 6 for montelukast (P<0.001). Physician satisfaction with treatment increased from 43% to 85% (P<0.001) and patient satisfaction increased from 45% at baseline to 94% at week 6. No serious adverse events were reported over the course of the study.

CONCLUSION

Montelukast is an effective and well-tolerated alternative to ICS treatment in patients with mild asthma who are uncontrolled or unsatisfied with low-dose ICS therapy.

Effect of betamethasone phosphate loaded polymeric nanoparticles on a murine asthma model

Although inhaled steroids are the treatment of first choice to control asthma, administration of systemic steroids is required for treatment of asthmatic exacerbation and intractable asthma. To improve efficacy and reduce side effects, we examine the effects of betamethasone disodium phosphate (BP) encapsulated in biocompatible, biodegradable blended nanoparticles (stealth nanosteroids) on a murine model of asthma. These stealth nanosteroids were found to accumulate at the site of airway inflammation and exhibit anti-inflammatory activity. Significant decreases in BALF eosinophil number were maintained for 7 days with a single injection of nanosteroids containing 40 microg BP. Airway responsiveness was also attenuated by the injection of stealth nanosteroids. A single injection of 40 microg of free BP and 8 microg of free BP once daily for 5 days did not show any significant effects. We conclude that stealth nanosteroids achieve prolonged and higher benefits at the site of airway inflammation compared to free steroids.

Comparison of inhaled corticosteroids: an update

OBJECTIVE

To review the basis for the estimated comparative daily dosages of inhaled corticosteroids for children and adults that are presented in the National Heart, Lung, and Blood Institute's Expert Panel Report 3; in addition, the pharmacodynamic and pharmacokinetic basis for potential clinical differences among inhaled corticosteroids is discussed.

DATA SOURCES

A complete MEDLINE search was conducted of human studies of asthma pharmacotherapy published between January 1, 2001, and March 15, 2006, followed by a PubMed search up until August 2008, using ciclesonide, inhaled corticosteroids, and pharmacokinetics as key words. Product information on each inhaled corticosteroid was also included.

STUDY SELECTION AND DATA EXTRACTION

Comparative clinical trials of inhaled corticosteroids and systematic reviews for efficacy comparisons were evaluated. Extensive literature reviews, meta-analyses, and selected clinical studies that illustrate or represent specific points of view were selected. Pharmacodynamic and pharmacokinetic data extracted from previously published reviews and specific studies were included.

DATA SYNTHESIS

Pharmacodynamic characteristics (glucocorticoid receptor binding) and lung delivery determine the relative clinical efficacy and pharmacokinetic properties (oral bioavailability, lung retention, systemic clearance) and determine comparative therapeutic index of the inhaled corticosteroids. Secondary pharmacokinetic differences (intracellular fatty acid esterification, high serum protein binding) that have been posited to improve duration of action and/or therapeutic index are unproven, and current comparative clinical trials do not support the hypotheses that they provide an advantage. Ultrafine particle meter-dose inhalers (MDIs) have not demonstrated superior asthma control or improved safety over older MDIs. All of the inhaled corticosteroids demonstrate efficacy with once-daily dosing, and all are more effective when dosed twice daily.

CONCLUSIONS

Current evidence suggests that all of the inhaled corticosteroids have sufficient therapeutic indexes to provide similar efficacy and safety in low to medium doses. Whether or not some of the newer inhaled corticosteroids offer any advantages at higher doses has yet to be determined.

Inhaled corticosteroids for asthma: are they all the same?

OBJECTIVES

To assess similarities and differences among currently available inhaled corticosteroids (ICS) for treatment of asthma, with special emphasis on factors that may affect the relative safety of these medications.

METHODS

PubMed was searched for relevant reviews and original articles. Information from these studies was synthesized and critically assessed.

RESULTS

Differences in corticosteroid formulations and delivery systems can create variations in therapeutic efficacy. Chemical properties of the various corticosteroids may also affect their relative safety. Ciclesonide and beclomethasone dipropionate are administered as prodrugs activated by enzymes present in the lungs but not the oropharynx. Corticosteroid-specific adverse effects in the oropharynx are thus avoided, although formulation-specific effects may remain. Other adverse effects require systemic availability, either via the gastrointestinal tract or the lung. Once they enter the systemic circulation, all ICS are rapidly metabolized by the liver. Oral bioavailability of ICS such as fluticasone, ciclesonide and mometasone is minimal, as a result of their essentially complete first-pass metabolism in the liver. Ciclesonide also undergoes extrahepatic metabolism that eliminates it even more rapidly. Additionally, ciclesonide and mometasone exhibit very high levels of binding to serum proteins that reduces their ability to stimulate glucocorticoid receptors outside the lung.

CONCLUSIONS

Despite acting by similar mechanisms, currently available ICS and their delivery systems differ in ways that can potentially affect both safety and therapeutic effectiveness for individual patients.

Ciclesonide: a review of its use in the management of asthma

Ciclesonide (Alvesco) is an inhaled corticosteroid used in the preventative treatment of persistent bronchial asthma in adults, adolescents and, in some countries, children. The drug is delivered by a non-chlorofluorocarbon hydrofluoroalkane (HFA) metered-dose inhaler (MDI). In the lungs, ciclesonide is converted to an active metabolite, which is responsible for the beneficial effects of the drug in patients with asthma. Ciclesonide and its active metabolite have low systemic bioavailability and therefore have a low potential to produce systemic adverse events. Inhaled ciclesonide delivered by HFA-MDI is effective in the prophylactic treatment of persistent asthma in adults, adolescents and children, and is generally well tolerated. In general, ciclesonide improves lung function and reduces asthma symptoms and rescue medication use in adults and adolescents with asthma of varying severity. The drug is generally no less effective than other inhaled corticosteroids with regard to maintaining or improving lung function and may have a more favourable tolerability profile than some other agents in this class. Ciclesonide has also shown efficacy in paediatric patients with asthma. Data on its long-term effects on other clinical outcomes, such as asthma exacerbations, would be of interest. Further comparative and long-term studies would also be beneficial in order to definitively position ciclesonide with respect to other inhaled corticosteroids. In the meantime, ciclesonide offers an effective and well tolerated first-line preventative treatment option for persistent asthma.

Isoliquiritigenin, a flavonoid from licorice, relaxes guinea-pig tracheal smooth muscle in vitro and in vivo: role of cGMP/PKG pathway

Licorice root is used to treat asthma as a component of Shaoyao-Gancao-tang, a traditional Chinese medicine formula. In this study, we investigated the tracheal relaxation effects of isoliquiritigenin, a flavonoid isolated from the roots of Glycyrrhiza glabra (a kind of Licorice), on guinea-pig tracheal smooth muscle in vitro and in vivo. The tension changes of isolated tracheal rings were isometrically recorded on a polygraph. The large-conductance Ca2+-activated K+ channels (BKCa) were measured by inside-out patch-clamp techniques and intracellular Ca2+concentrations ([Ca2+]i) were tested by microfluorometric method in guinea-pig tracheal smooth muscle cells (TSMCs). Isoliquiritigenin produced concentration-dependent relaxation in isolated guinea-pig tracheal rings precontracted with acetylcholine, KCl, and histamine. Pretreatments with charybdotoxin, ODQ and KT5823 attenuated the relaxation induced by isoliquiritigenin. Isoliquiritigenin significantly increased intracellular cGMP level in cultured TSMCs and inhibited the activity of phosphodiesterase (PDE) 5 in human platelets. Moreover, isoliquiritigenin increased by 9-fold the probability of BKCa channel openings of TSMCs in inside-out patches and markedly reduced [Ca2+]i rise induced by acetylcholine inTSMCs, pretreatment with KT5823 attenuated above two responses to isoliquiritigenin. In vivo experiment isoliquiritigenin significantly prolonged the latency time of histamine-acetylcholine aerosol-induced collapse and inhibited the increase of lung overflow induced by intravenously administered histamine dose-dependently. These data indicate that isoliquiritigenin relaxes guinea-pig trachea through a multiple of intracellular actions, including sGC activation, inhibition of PDEs, and associated activation of the cGMP/PKG signaling cascade, leading to the opening of BKCa channels and [Ca2+]i decrease through PKG-dependent mechanism and thus to tracheal relaxation.

Modulation of human lung fibroblast functions by ciclesonide: evidence for its conversion into the active metabolite desisobutyryl-ciclesonide

BACKGROUND

Ciclesonide, an inhaled corticosteroid administered as inactive compound with almost no binding affinity for the glucocorticoid receptor, is clinically effective in asthma being converted by airway epithelial cells into its active metabolite desisobutyryl-(des)-ciclesonide.

AIM

To evaluate whether ciclesonide could directly modulate in vitro bronchial fibroblast functions being converted into des-ciclesonide by these pluripotent cells involved in the regulation of airway inflammation and remodelling.

METHODS

Ciclesonide (0.09-9.0 microM) was added to a human adult lung fibroblast cell line (CCL-202), seeded in medium in the presence of the following cytokines and growth factors: (a) basic fibroblast growth factor (bFGF) for cell proliferation, measured by tritiated thymidine ([3H]TdR) incorporation; (b) tumour necrosis factor (TNF)-alpha, to stimulate intercellular adhesion molecule (ICAM)-1 expression and monocyte chemoattractant protein-1 (MCP-1) and eotaxin release, evaluated by flow cytometry and ELISA, respectively; (c) transforming growth factor (TGF)-beta1, for induction of alpha smooth muscle actin (alpha-SMA) protein expression and modification of the organization of alpha-SMA stress fibres, evaluated by Western blot analysis and fluorescence microscopy.

RESULTS

The presence of ciclesonide in cell cultures induced a significant downregulation of: (a) bFGF-induced fibroblast proliferation and TNF-alpha-induced ICAM-1 expression, at the 0.3-9.0 microM concentrations (p<0.05); (b) TNF-alpha-induced MCP-1 release, at all the concentrations tested (p<0.05); (c) TNF-alpha-induced eotaxin release, at the three highest concentrations (0.9-9.0 microM) (p<0.05); (d) TGF-beta1-induced of alpha-SMA protein expression at the 0.3-3.0 microM concentrations, associated with a reduction in the organization of alpha-SMA stress fibres.

CONCLUSIONS

These data show at cellular level an effective anti-inflammatory activity of ciclesonide on human lung fibroblasts and support the hypothesis that also these cells, in addition to airway epithelial cells, may be involved in converting the parental compound into its active metabolite in the airways.

Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma

Asthma is an increasingly common disorder responsible for considerable morbidity and mortality. Although obesity is a risk factor for asthma and weight loss can improve symptoms, many patients do not adhere to low calorie diets and the impact of dietary restriction on the disease process is unknown. A study was designed to determine if overweight asthma patients would adhere to an alternate day calorie restriction (ADCR) dietary regimen, and to establish the effects of the diet on their symptoms, pulmonary function and markers of oxidative stress, and inflammation. Ten subjects with BMI>30 were maintained for 8 weeks on a dietary regimen in which they ate ad libitum every other day, while consuming less than 20% of their normal calorie intake on the intervening days. At baseline, and at designated time points during the 8-week study, asthma control, symptoms, and Quality of Life questionnaires (ACQ, ASUI, mini-AQLQ) were assessed and blood was collected for analyses of markers of general health, oxidative stress, and inflammation. Peak expiratory flow (PEF) was measured daily on awakening. Pre- and postbronchodilator spirometry was obtained at baseline and 8 weeks. Nine of the subjects adhered to the diet and lost an average of 8% of their initial weight during the study. Their asthma-related symptoms, control, and QOL improved significantly, and PEF increased significantly, within 2 weeks of diet initiation; these changes persisted for the duration of the study. Spirometry was unaffected by ADCR. Levels of serum beta-hydroxybutyrate were increased and levels of leptin were decreased on CR days, indicating a shift in energy metabolism toward utilization of fatty acids and confirming compliance with the diet. The improved clinical findings were associated with decreased levels of serum cholesterol and triglycerides, striking reductions in markers of oxidative stress (8-isoprostane, nitrotyrosine, protein carbonyls, and 4-hydroxynonenal adducts), and increased levels of the antioxidant uric acid. Indicators of inflammation, including serum tumor necrosis factor-alpha and brain-derived neurotrophic factor, were also significantly decreased by ADCR. Compliance with the ADCR diet was high, symptoms and pulmonary function improved, and oxidative stress and inflammation declined in response to the dietary intervention. These findings demonstrate rapid and sustained beneficial effects of ADCR on the underlying disease process in subjects with asthma, suggesting a novel approach for therapeutic intervention in this disorder.