Advair: combination treatment with fluticasone propionate/salmeterol in the treatment of asthma

Late-stage modification of bioactive compounds: Improving druggability through efficient molecular editing

Synthetic chemistry plays an indispensable role in drug discovery, contributing to hit compounds identification, lead compounds optimization, candidate drugs preparation, and so on. As Nobel Prize laureate James Black emphasized, "the most fruitful basis for the discovery of a new drug is to start with an old drug"1. Late-stage modification or functionalization of drugs, natural products and bioactive compounds have garnered significant interest due to its ability to introduce diverse elements into bioactive compounds promptly. Such modifications alter the chemical space and physiochemical properties of these compounds, ultimately influencing their potency and druggability. To enrich a toolbox of chemical modification methods for drug discovery, this review focuses on the incorporation of halogen, oxygen, and nitrogen-the ubiquitous elements in pharmacophore components of the marketed drugs-through late-stage modification in recent two decades, and discusses the state and challenges faced in these fields. We also emphasize that increasing cooperation between chemists and pharmacists may be conducive to the rapid discovery of new activities of the functionalized molecules. Ultimately, we hope this review would serve as a valuable resource, facilitating the application of late-stage modification in the construction of novel molecules and inspiring innovative concepts for designing and building new drugs.

Efficacy and safety of fluticasone propionate/salmeterol and fluticasone propionate monotherapy in step-up treatment of childhood asthma: A systematic review and meta-analysis

BACKGROUND

Asthma is a chronic respiratory disease that affects millions of children worldwide and can impair their quality of life and development. Inhaled glucocorticoids are the mainstay of asthma treatment, but some children require step-up therapy with additional drugs to achieve symptom control. Fluticasone propionate and salmeterol (FSC) has been shown to reduce asthma exacerbations and improve lung function in adults. However, the evidence for its efficacy and safety in children is limited.

OBJECTIVE

This study aims to provide a comprehensive basis for treatment selection by summarizing existing clinical randomized controlled trials (RCTs) on the efficacy of FSC compared to fluticasone propionate (FP) monotherapy in children with asthma who require step-up treatment.

METHODS

Five online databases and three clinical trial registration platforms were systematically searched. The effect size and corresponding 95% confidence interval (CI) were calculated based on the heterogeneity among the included studies.

RESULTS

Twelve RCTs were identified and a total of 9, 859 patients were involved. The results of the meta-analysis revealed that the use of FSC was associated with a greater reduction in the incidence of asthma exacerbations than FP alone when the dose of FP was the same or when the duration of treatment exceeded 12 weeks. In addition, FSC resulted in a greater proportion of time with asthma-free and without the use of albuterol compared to FP alone when the duration of treatment exceeded 12 weeks. No significant differences were observed between FSC and FP alone in the incidence of drug-related adverse events and other adverse events.

CONCLUSION

Both FSC and FP alone are viable options for the initial selection of step-up treatment in asthmatic children. While, FSC treatment demonstrates a greater likelihood of reducing asthma exacerbations which is particularly important for reducing the personnel, social and economic burden in children requiring step-up asthma treatment.

Multi-task learning for predicting synergistic drug combinations based on auto-encoding multi-relational graphs

Combinatorial drug therapy is a promising approach for treating complex diseases by combining drugs with synergistic effects. However, predicting effective drug combinations is challenging due to the complexity of biological systems and the limited understanding of pathophysiological mechanisms and drug targets. In this paper, we proposed a computational framework called VGAETF (Variational Graph Autoencoder Tensor Decomposition), which leveraged multi-relational graph to model complex relationships between entities in biological systems and predicted disease-related synergistic drug combinations in an end-to-end manner. In the computational experiments, VGAETF achieved high performances (AUROC [the area under receiver operating characteristic] = 0.9767, AUPR [the area under precision-recall] = 0.9660), outperforming other compared methods. Moreover, case studies further demonstrated the effectiveness of VGAETF in identifying potential disease-related synergistic drug combinations.

Drug Combination Modeling: Methods and Applications in Drug Development

Combination therapies have become increasingly researched and used in the treatment and management of complex diseases due to their ability to increase the chances for better efficacy and decreased toxicity. To evaluate drug combinations in drug development, pharmacokinetic and pharmacodynamic interactions between drugs in combination can be quantified using mathematical models; however, it can be difficult to deduce which models to use and how to use them to aid in clinical trial simulations to simulate the effect of a drug combination. This review paper aims to provide an overview of the various methods used to evaluate combination drug interaction for use in clinical trial development and a practical guideline on how combination modeling can be used in the settings of clinical trials.

Combination of Antidepressants and Antipsychotics as A Novel Treatment Option for Psychosis in Alzheimer's Disease

Background

Psychotic symptoms are reported as one of the most common complications of Alzheimer's disease (AD), affecting approximately half of AD patients, in whom they are associated with more rapid deterioration and increased mortality. Empiric treatments, namely first and second-generation antipsychotics, confer modest efficacy in AD patients with psychosis (AD+P) and themselves increase mortality. A recent genome-wide meta-analysis and early clinical trials suggest the use and beneficial effects of antidepressants among AD+P patients. This motivates our rationale for exploring their potential as a novel combination therapy option amongst these patients.

Methods

We included University of Pittsburgh Medical Center (UPMC) electronic medical records (EMRs) of 10,260 AD patients from January 2004 and October 2019 in our study. Survival analysis was performed to assess the effects of the combination of antipsychotics and antidepressants on the mortality of these patients. To provide more valuable insights on the hidden mechanisms of the combinatorial therapy, a protein-protein interaction (PPI) network representing AD+P was built, and network analysis methods were used to quantify the efficacy of these drugs on AD+P. An indicator score combining the measurements on the separation between drugs and the proximity between the drugs and AD+P was used to measure the effect of an antipsychotic-antidepressant drug pair against AD+P.

Results

Our survival analyses replicated that antipsychotic usage is strongly associated with increased mortality in AD patients while the co-administration of antidepressants with antipsychotics showed a significant beneficial effect in reducing mortality. Our network analysis showed that the targets of antipsychotics and antidepressants are well-separated, and antipsychotics and antidepressants have similar proximity scores to AD+P. Eight drug pairs, including some popular recommendations like Aripiprazole/Sertraline and other pairs not reported previously like Iloperidone/Maprotiline showed higher than average indicator scores which suggest their potential in treating AD+P via strong synergetic effects as seen in our study.

Conclusion

Our proposed combinations of antipsychotics and antidepressants therapy showed a strong superiority over current antipsychotics treatment for AD+P. The observed beneficial effects can be further strengthened by optimizing drug-pair selection based on our systems pharmacology analysis.

Purinergic Receptors P2X7 and P2X4 as Markers of Disease Progression in the rd10 Mouse Model of Inherited Retinal Dystrophy

The purinergic receptor P2X7 (P2X7R) is implicated in all neurodegenerative diseases of the central nervous system. It is also involved in the retinal degeneration associated with glaucoma, age-related macular degeneration, and diabetic retinopathy, and its overexpression in the retina is evident in these disorders. Retinitis pigmentosa is a progressive degenerative disease that ultimately leads to blindness. Here, we investigated the expression of P2X7R during disease progression in the rd10 mouse model of RP. As the purinergic receptor P2X4 is widely co-expressed with P2X7R, we also studied its expression in the retina of rd10 mice. The expression of P2X7R and P2X4R was examined by immunohistochemistry, flow cytometry, and western blotting. In addition, we analyzed retinal functionality by electroretinographic recordings of visual responses and optomotor tests and retinal morphology. We found that the expression of P2X7R and P2X4R increased in rd10 mice concomitant with disease progression, but with different cellular localization. Our findings suggest that P2X7R and P2X4R might play an important role in RP progression, which should be further analyzed for the pharmacological treatment of inherited retinal dystrophies.

Non-parametric synergy modeling of chemical compounds with Gaussian processes

Background

Understanding the synergetic and antagonistic effects of combinations of drugs and toxins is vital for many applications, including treatment of multifactorial diseases and ecotoxicological monitoring. Synergy is usually assessed by comparing the response of drug combinations to a predicted non-interactive response from reference (null) models. Possible choices of null models are Loewe additivity, Bliss independence and the recently rediscovered Hand model. A different approach is taken by the MuSyC model, which directly fits a generalization of the Hill model to the data. All of these models, however, fit the dose–response relationship with a parametric model.

Results

We propose the Hand-GP model, a non-parametric model based on the combination of the Hand model with Gaussian processes. We introduce a new logarithmic squared exponential kernel for the Gaussian process which captures the logarithmic dependence of response on dose. From the monotherapeutic response and the Hand principle, we construct a null reference response and synergy is assessed from the difference between this null reference and the Gaussian process fitted response. Statistical significance of the difference is assessed from the confidence intervals of the Gaussian process fits. We evaluate performance of our model on a simulated data set from Greco, two simulated data sets of our own design and two benchmark data sets from Chou and Talalay. We compare the Hand-GP model to standard synergy models and show that our model performs better on these data sets. We also compare our model to the MuSyC model as an example of a recent method on these five data sets and on two-drug combination screens: Mott et al. anti-malarial screen and O’Neil et al. anti-cancer screen. We identify cases in which the HandGP model is preferred and cases in which the MuSyC model is preferred.

Conclusion

The Hand-GP model is a flexible model to capture synergy. Its non-parametric and probabilistic nature allows it to model a wide variety of response patterns.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-021-04508-7.

The economics of precision health: preventing air pollution-induced exacerbation in asthma

The demonstrable value of precision medicine, in the context of common environmental exposures, has scarcely been explored. This study evaluated the cost effectiveness of a preventive personalised intervention to reduce the adverse effect of air pollution in the context of asthma.

A decision–analytic model was used to conduct a cost-utility analysis of prevention interventions in case of acute exposure to air pollution in mild asthma. Three different strategies, as follows, were compared: no preventive intervention; precision health strategy based on information from genotype testing, followed with treating high-risk patients; and prescribing additional medication to all mild asthmatics as a preventive intervention. The costs and quality-adjusted life years (QALYs) in the base case and alternative scenarios were obtained through probabilistic analysis.

The results showed that the precision prevention intervention (anticipatory intervention for asthmatics, guided by relevant genetic abnormality, in the face of acute air pollution) is a cost-effective strategy compared with no such intervention, with an incremental cost-effectiveness ratio of CAD 49 555 per QALY. Furthermore, this strategy is a dominant strategy compared with an intervention that prescribes medication indiscriminately to all asthmatics.

The incorporation of genomic testing to stratify risk of asthmatics to pollution-driven exacerbations, and then tailoring a preventive intervention accordingly, may be cost effective relative to untailored methods. These results lend plausibility to the use of precision medicine for limiting asthma exacerbation in the context of air pollution and, potentially, other exposures.

Glutathione-S-transferase genotyping to determine the use of preventive asthma medication in the face of air pollution is cost effective in this model. Precision prevention in the setting of common environmental exposures may be used in other contexts.https://bit.ly/35Lab4b

A new formulation of fluticasone propionate/salmeterol in a metered-dose inhaler (MDI HFA) allows for the reduction of a daily dose of corticosteroid and provides optimal asthma control - A randomized, multi-center, non-inferiority, phase IV clinical study

BACKGROUND

Improvement of the delivery method of inhaled corticosteroids and subsequent dose reduction can minimize the risk of unfavorable outcomes while providing optimal asthma control.

OBJECTIVE

This randomized, multi-center, non-inferiority, phase IV clinical study compared the efficacy and safety of a new formulation of fluticasone propionate/salmeterol (250 μg/50 μg, twice daily) administered in a metered-dose inhaler hydrofluoroalkane (MDI HFA) with a dry-powder inhaler (DPI) containing fluticasone propionate/salmeterol (500 μg/50 μg, twice daily).

METHODS

Adults with asthma (n = 231) were randomly assigned to either the study group (treated for 12 weeks with fluticasone propionate/salmeterol MDI HFA) or a control group (treated for 12 weeks with fluticasone propionate/salmeterol DPI). Asthma symptoms, exacerbations, short-acting β₂-agonist (SABA) use, physical activity, lung function, and general health status were assessed during four study visits.

RESULTS

Compared with the reference drug, the study drug decreased the incidence of daytime and night-time asthma symptoms, asthma exacerbations, self-administration of SABA, and the limitation of physical activity. Comparable improvement in peak expiratory flow ([MDI HFA] from 6.2 ± 0.2 to 6.6 ± 0.2 l/s vs. [DPI] from 6.0 ± 0.2 to 6.9 ± 0.2 l/s; p > 0.05), forced expiratory volume in one second, and forced vital capacity were obtained in both groups. Significantly lower incidence of hoarseness was observed in the study group ([MDI HFA] 0.0% vs. [DPI] 2.8%; p = 0.0267); no major differences were found for other adverse events.

CONCLUSIONS

Fluticasone propionate/salmeterol (250 μg/50 μg, twice daily) MDI HFA provides optimal asthma control and is non-inferior to fluticasone propionate/salmeterol (500 μg/50 μg, twice daily) DPI.

Emerging trends in inhaled drug delivery

Ideally, inhaled therapy is driven by the needs of specific disease management. Lung biology interfaces with inhaler performance to allow optimal delivery of therapeutic agent for disease treatment. Inhalation aerosol products consist of the therapeutic agent, formulation, and device. The manufacturing specifications on each of the components, and their combination, allow accurate and reproducible control of measures of quality and in-vitro performance. These product variables in combination with patient variables, including co-ordination skill during inhaler use, intrinsic lung biology, disease and consequent pulmonary function, contribute to drug safety and efficacy outcomes. Due to the complexity of pulmonary drug delivery, predicting biological outcomes from first principles has been challenging. Ongoing research appears to offer new insights that may allow accurate prediction of drug behavior in the lungs. Disruptive innovations were characteristic of research and development in inhaled drug delivery at the end of the last century. Although there were relatively few new inhaled products launched in the first decade of the new millennium it was evident that the earlier years of exploration resulted in maturation of commercially successful technologies. A significant increase in new and generic products has occurred in the last decade and technical, regulatory and disease management trends are emerging. Some of these developments can trace their origins to earlier periods of creativity in the field while others are a reflection of advances in other areas of basic and computer, sciences and engineering. Select biological and technical advances are highlighted with reflections on the potential to impact future clinical and regulatory considerations.

Racial/Ethnic-Specific Differences in the Effects of Inhaled Corticosteroid Use on Bronchodilator Response in Patients With Asthma

American Thoracic Society guidelines recommend inhaled corticosteroid (ICS) therapy, plus a short-acting bronchodilator, in patients with persistent asthma. However, few prior studies have examined the efficacy of this combination in children of all racial/ethnic groups. We evaluated the association between ICS use and bronchodilator response (BDR) in three pediatric populations with persistent asthma (656 African American, 916 Puerto Rican, and 398 Mexican American children). The association was assessed using multivariable quantile regression. After adjusting for baseline forced expiratory volume in one second and use of controller medications, ICS use was significantly associated with increased BDR only among Mexican Americans (1.56%, P = 0.028) but not African Americans (0.49%, P = 0.426) or Puerto Ricans (0.16%, P = 0.813). Our results demonstrate that ICS augmentation is disproportionate across racial/ethnic groups, where improved BDR is observed in Mexican Americans only. This study highlights the complexities of treating asthma in children, and reinforces the importance of investigating the influence of race/ethnicity on pharmacological response.

Current Methods for Quantifying Drug Synergism

The effectiveness of drug combinations for treatment of a variety of complex diseases is well established. "Drug cocktail" treatments are often prescribed to improve the overall efficacy, decrease toxicity, alter pharmacodynamics, etc in an overall treatment strategy. Specifically, if when combined, drugs interact in some way that causes the total effect to be greater than that predicted by their individual potencies, then drugs are considered synergistic. While there are established ways to quantify the impact of drug combinations clinically, it is an open challenge to quantitatively summarize a synergistic interaction. In this paper, we discuss an overview of the current statistical and mathematical methods for the study of drug combination effects, especially drug synergy quantification (where the interaction effect is not just detected, but quantified according to its magnitude). We first introduce two popular reference models for testing to null hypothesis of non-interaction for a combination, including the Bliss independence model and the Loewe additivity model. Then we discuss several methods for quantifying drug synergism. The advantages and disadvantages with these methods are also provided, and finally, we discuss important next directions in this area.

Pairwise combinations of chemical compounds that delay yeast chronological aging through different signaling pathways display synergistic effects on the extent of aging delay

We have recently discovered six plant extracts that delay yeast chronological aging. Most of them affect different nodes, edges and modules of an evolutionarily conserved network of longevity regulation that integrates certain signaling pathways and protein kinases; this network is also under control of such aging-delaying chemical compounds as spermidine and resveratrol. We have previously shown that, if a strain carrying an aging-delaying single-gene mutation affecting a certain node, edge or module of the network is exposed to some of the six plant extracts, the mutation and the plant extract enhance aging-delaying efficiencies of each other so that their combination has a synergistic effect on the extent of aging delay. We therefore hypothesized that a pairwise combination of two aging-delaying plant extracts or a combination of one of these plant extracts and spermidine or resveratrol may have a synergistic effect on the extent of aging delay only if each component of this combination targets a different element of the network. To test our hypothesis, we assessed longevity-extending efficiencies of all possible pairwise combinations of the six plant extracts or of one of them and spermidine or resveratrol in chronologically aging yeast. In support of our hypothesis, we show that only pairwise combinations of naturally-occurring chemical compounds that slow aging through different nodes, edges and modules of the network delay aging in a synergistic manner.

The Prediction of Drug-Disease Correlation Based on Gene Expression Data

The explosive growth of high-throughput experimental methods and resulting data yields both opportunity and challenge for selecting the correct drug to treat both a specific patient and their individual disease. Ideally, it would be useful and efficient if computational approaches could be applied to help achieve optimal drug-patient-disease matching but current efforts have met with limited success. Current approaches have primarily utilized the measureable effect of a specific drug on target tissue or cell lines to identify the potential biological effect of such treatment. While these efforts have met with some level of success, there exists much opportunity for improvement. This specifically follows the observation that, for many diseases in light of actual patient response, there is increasing need for treatment with combinations of drugs rather than single drug therapies. Only a few previous studies have yielded computational approaches for predicting the synergy of drug combinations by analyzing high-throughput molecular datasets. However, these computational approaches focused on the characteristics of the drug itself, without fully accounting for disease factors. Here, we propose an algorithm to specifically predict synergistic effects of drug combinations on various diseases, by integrating the data characteristics of disease-related gene expression profiles with drug-treated gene expression profiles. We have demonstrated utility through its application to transcriptome data, including microarray and RNASeq data, and the drug-disease prediction results were validated using existing publications and drug databases. It is also applicable to other quantitative profiling data such as proteomics data. We also provide an interactive web interface to allow our Prediction of Drug-Disease method to be readily applied to user data. While our studies represent a preliminary exploration of this critical problem, we believe that the algorithm can provide the basis for further refinement towards addressing a large clinical need.

Network motifs modulate druggability of cellular targets

Druggability refers to the capacity of a cellular target to be modulated by a small-molecule drug. To date, druggability is mainly studied by focusing on direct binding interactions between a drug and its target. However, druggability is impacted by cellular networks connected to a drug target. Here, we use computational approaches to reveal basic principles of network motifs that modulate druggability. Through quantitative analysis, we find that inhibiting self-positive feedback loop is a more robust and effective treatment strategy than inhibiting other regulations, and adding direct regulations to a drug-target generally reduces its druggability. The findings are explained through analytical solution of the motifs. Furthermore, we find that a consensus topology of highly druggable motifs consists of a negative feedback loop without any positive feedback loops, and consensus motifs with low druggability have multiple positive direct regulations and positive feedback loops. Based on the discovered principles, we predict potential genetic targets in Escherichia coli that have either high or low druggability based on their network context. Our work establishes the foundation toward identifying and predicting druggable targets based on their network topology.

Analysis of drug combinations: current methodological landscape

Combination therapies exploit the chances for better efficacy, decreased toxicity, and reduced development of drug resistance and owing to these advantages, have become a standard for the treatment of several diseases and continue to represent a promising approach in indications of unmet medical need. In this context, studying the effects of a combination of drugs in order to provide evidence of a significant superiority compared to the single agents is of particular interest. Research in this field has resulted in a large number of papers and revealed several issues. Here, we propose an overview of the current methodological landscape concerning the study of combination effects. First, we aim to provide the minimal set of mathematical and pharmacological concepts necessary to understand the most commonly used approaches, divided into effect-based approaches and dose-effect-based approaches, and introduced in light of their respective practical advantages and limitations. Then, we discuss six main common methodological issues that scientists have to face at each step of the development of new combination therapies. In particular, in the absence of a reference methodology suitable for all biomedical situations, the analysis of drug combinations should benefit from a collective, appropriate, and rigorous application of the concepts and methods reviewed here.

Role of combined indacaterol and glycopyrronium bromide (QVA149) for the treatment of COPD in Japan

Once-daily dual-bronchodilator therapy with combined indacaterol and glycopyrronium bromide in one device (Ultibro, Breezhaler), often called QVA149, was first approved in 2013 in Japan and Europe. As of November 2014, more than 40 countries had approved this medication except for the USA. This is the first dual bronchodilator in one device. Now, the Breezhaler is the only device that can provide long-acting muscarinic antagonist (glycopyrronium bromide), long-acting beta agonist (indacaterol), and a combination of the two medications (QVA149). The choice among the three medications allows a patient to use the same inhalation device even when the regimen is changed from single-bronchodilator therapy to dual-bronchodilator therapy. In addition, the quick bronchodilation effect and once-daily administration can improve patient adherence to medical treatment for chronic obstructive pulmonary disease (COPD). To our knowledge, as of November 2014, the safety and the efficacy of QVA149 have been evaluated in 14 randomized controlled trials. The 14 trials generally showed good safety profiles, and there were better or not-inferior bronchodilator effects of QVA149 when compared with placebo, or other inhaled medication. According to the Japanese Respiratory Society guidelines, QVA149 is a combination of the two first-line bronchodilators. Our meta-analysis indicated that QVA149 is superior to the salmeterol-fluticasone combination to treat COPD in respect of the frequency of adverse effects, exacerbation, pneumonia, and improvement of trough forced expiratory volume in 1 second (FEV1). Thus, we believe that QVA149 can be a key medication for COPD treatments.

DIGRE: Drug-Induced Genomic Residual Effect Model for Successful Prediction of Multidrug Effects

Multidrug regimens are a promising strategy for improving therapeutic efficacy and reducing side effects, especially for complex disorders such as cancer. However, the use of multidrug therapies is very challenging, due to a lack of understanding of the mechanisms of drug interactions. We herein present a novel computational approach-Drug-Induced Genomic Residual Effect (DIGRE) Computational Model-to predict drug combination effects by explicitly modeling drug response curves and gene expression changes after drug treatments. The prediction performance of DIGRE was evaluated using two datasets: (i) OCI-LY3 B-lymphoma cells treated with 14 different drugs and (ii) MCF breast cancer cells treated with combinations of gefitinib and docetaxel at different doses. In both datasets, the predicted drug combination effects significantly correlated with the experimental results. The results indicated the model was useful in predicting drug combination effects, which may greatly facilitate the discovery of new, effective multidrug therapies.

A community computational challenge to predict the activity of pairs of compounds

Recent therapeutic successes have renewed interest in drug combinations, but experimental screening approaches are costly and often identify only small numbers of synergistic combinations. The DREAM consortium launched an open challenge to foster the development of in silico methods to computationally rank 91 compound pairs, from the most synergistic to the most antagonistic, based on gene-expression profiles of human B cells treated with individual compounds at multiple time points and concentrations. Using scoring metrics based on experimental dose-response curves, we assessed 32 methods (31 community-generated approaches and SynGen), four of which performed significantly better than random guessing. We highlight similarities between the methods. Although the accuracy of predictions was not optimal, we find that computational prediction of compound-pair activity is possible, and that community challenges can be useful to advance the field of in silico compound-synergy prediction.

Metabolic cancer biology: structural-based analysis of cancer as a metabolic disease, new sights and opportunities for disease treatment

The cancer cell metabolism or the Warburg effect discovery goes back to 1924 when, for the first time Otto Warburg observed, in contrast to the normal cells, cancer cells have different metabolism. With the initiation of high throughput technologies and computational systems biology, cancer cell metabolism renaissances and many attempts were performed to revise the Warburg effect. The development of experimental and analytical tools which generate high-throughput biological data including lots of information could lead to application of computational models in biological discovery and clinical medicine especially for cancer. Due to the recent availability of tissue-specific reconstructed models, new opportunities in studying metabolic alteration in various kinds of cancers open up. Structural approaches at genome-scale levels seem to be suitable for developing diagnostic and prognostic molecular signatures, as well as in identifying new drug targets. In this review, we have considered these recent advances in structural-based analysis of cancer as a metabolic disease view. Two different structural approaches have been described here: topological and constraint-based methods. The ultimate goal of this type of systems analysis is not only the discovery of novel drug targets but also the development of new systems-based therapy strategies.

Controllability in cancer metabolic networks according to drug targets as driver nodes

Networks are employed to represent many nonlinear complex systems in the real world. The topological aspects and relationships between the structure and function of biological networks have been widely studied in the past few decades. However dynamic and control features of complex networks have not been widely researched, in comparison to topological network features. In this study, we explore the relationship between network controllability, topological parameters, and network medicine (metabolic drug targets). Considering the assumption that targets of approved anticancer metabolic drugs are driver nodes (which control cancer metabolic networks), we have applied topological analysis to genome-scale metabolic models of 15 normal and corresponding cancer cell types. The results show that besides primary network parameters, more complex network metrics such as motifs and clusters may also be appropriate for controlling the systems providing the controllability relationship between topological parameters and drug targets. Consequently, this study reveals the possibilities of following a set of driver nodes in network clusters instead of considering them individually according to their centralities. This outcome suggests considering distributed control systems instead of nodal control for cancer metabolic networks, leading to a new strategy in the field of network medicine.

Risk factors of local oropharyngeal and laryngeal adverse effects from use of single inhaled corticosteroids and long-acting beta-agonists

BACKGROUND

Single inhaled corticosteroids and long-acting beta-agonists (ICS/LABA) are clinically effective and safe. However, if local oropharyngeal and laryngeal adverse effects (LOLAE) appear, adherence to the use of ICS is impaired. To minimize the development of adverse effects, it is essential to identify the underlying risk factors.

METHODS

The study included 481 asthmatic patients who were prescribed ICS/LABA for the first time in their life between January and September of 2010. Patients ranged in age from 14 to 86 years old and consisted of 281 never smokers and 200 smokers. All data were collected retrospectively by respirologists.

RESULTS

Seventy-three out of 481 patients suffered from one or more adverse effects, with 54 of these exhibiting LOLAE. Patients with LOLAE (51.4 ± 16.2 yrs) were significantly older than those without LOLAE (43.7 ± 15.9 yrs) (p = 0.0011) and were also prescribed a significantly higher dose of ICS. The pack-years of patients with LOLAE (2.1 ± 4.9) were significantly lower than those without LOLAE (6.0 ± 13.0) (p = 0.0087). The type of administered ICS was also significantly associated with a risk of developing LOLAE.

CONCLUSIONS

Our survey indicated that a greater age, a higher dose of ICS, and the type of ICS were potential risk factors of LOLAE. The identified factors should be considered in a clinical setting in order to prevent the development of LOLAE and provide optimal treatment to patients.

CDA: combinatorial drug discovery using transcriptional response modules

Background

Anticancer therapies that target single signal transduction pathways often fail to prevent proliferation of cancer cells because of overlapping functions and cross-talk between different signaling pathways. Recent research has identified that balanced multi-component therapies might be more efficacious than highly specific single component therapies in certain cases. Ideally, synergistic combinations can provide 1) increased efficacy of the therapeutic effect 2) reduced toxicity as a result of decreased dosage providing equivalent or increased efficacy 3) the avoidance or delayed onset of drug resistance. Therefore, the interest in combinatorial drug discovery based on systems-oriented approaches has been increasing steadily in recent years.

Methodology

Here we describe the development of Combinatorial Drug Assembler (CDA), a genomics and bioinformatics system, whereby using gene expression profiling, multiple signaling pathways are targeted for combinatorial drug discovery. CDA performs expression pattern matching of signaling pathway components to compare genes expressed in an input cell line (or patient sample data), with expression patterns in cell lines treated with different small molecules. Then it detects best pattern matching combinatorial drug pairs across the input gene set-related signaling pathways to detect where gene expression patterns overlap and those predicted drug pairs could likely be applied as combination therapy. We carried out in vitro validations on non-small cell lung cancer cells and triple-negative breast cancer (TNBC) cells. We found two combinatorial drug pairs that showed synergistic effect on lung cancer cells. Furthermore, we also observed that halofantrine and vinblastine were synergistic on TNBC cells.

Conclusions

CDA provides a new way for rational drug combination. Together with phExplorer, CDA also provides functional insights into combinatorial drugs. CDA is freely available at http://cda.i-pharm.org.

Meta-analysis of the efficacy and safety of bronchial thermoplasty in patients with moderate-to-severe persistent asthma

This meta-analysis assessed the efficacy and safety of a novel intervention for asthma, bronchial thermoplasty (BT), in patients with moderate-to-severe persistent asthma. An electronic literature search identified three randomized controlled trials (RCT) of BT that recruited 421 patients in total. Outcomes of interest were the Asthma Quality of Life Questionnaire (AQLQ) score, morning peak expiratory flow (PEF), tolerability and safety. Compared with standard medications and sham BT treatment, BT significantly improved AQLQ scores and PEF from baseline to the end of the trials. There were more respiratory adverse events and hospitalizations for adverse respiratory events with BT than with medications or sham treatment during the treatment period, but most events resolved, on average, within a week. This effect of BT treatment was not seen during the posttreatment period. Additional long-term RCT are required to confirm whether BT provides benefit to patients with moderate-to-severe persistent asthma.

Multidetector row computed tomography to assess changes in airways linked to asthma control

BACKGROUND

In asthma, multidetector row computed tomography (MDCT) detects abnormalities that are related to disease severity, including increased bronchial wall thickness. However, whether these abnormalities could be related to asthma control has not been investigated yet.

OBJECTIVE

Our goal was to determine which changes in airways could be linked to disease control.

METHODS

Twelve patients with poor asthma control were included and received a salmeterol/fluticasone propionate combination daily for 12 weeks. Patients underwent clinical, functional, and MDCT examinations before and after the treatment period. MDCT examinations were performed using a low-dose protocol at a controlled lung volume (65% TLC). Bronchial lumen (LA) and wall areas (WA) were evaluated at a segmental and subsegmental level using BronCare software. Lung density was measured at the base of the lung. Baseline and end-of-treatment data were compared using the Wilcoxon signed-rank test.

RESULTS

After the 12-week treatment period, asthma control was achieved. Airflow obstruction and air trapping decreased as assessed by the changes in FEV(1) (p < 0.01) and expiratory reserve volume (p < 0.01). Conversely, LA and WA did not vary significantly. However, a median decrease in LA of >10% was observed in half of the patients with a wide intra- and intersubject response heterogeneity. This was concomitant with a decrease in lung density (p < 0.02 in the anteroinferior areas).

CONCLUSIONS

MDCT is insensitive for demonstrating any decrease in bronchial wall thickness. This is mainly due to changes in bronchial caliber which may be linked to modifications of the elastic properties of the bronchopulmonary system under treatment.

Dynamical analysis of cellular networks based on the Green's function matrix

The complexity of cellular networks often limits human intuition in understanding functional regulations in a cell from static network diagrams. To this end, mathematical models of ordinary differential equations (ODEs) have commonly been used to simulate dynamical behavior of cellular networks, to which a quantitative model analysis can be applied in order to gain biological insights. In this paper, we introduce a dynamical analysis based on the use of Green's function matrix (GFM) as sensitivity coefficients with respect to initial concentrations. In contrast to the classical (parametric) sensitivity analysis, the GFM analysis gives a dynamical, molecule-by-molecule insight on how system behavior is accomplished and complementarily how (impulse) signal propagates through the network. The knowledge gained will have application from model reduction and validation to drug discovery research in identifying potential drug targets, studying drug efficacy and specificity, and optimizing drug dosing and timing. The efficacy of the method is demonstrated through applications to common network motifs and a Fas-induced programmed cell death model in Jurkat T cell line.

Mechanisms of drug combinations: interaction and network perspectives

Understanding the molecular mechanisms underlying synergistic, potentiative and antagonistic effects of drug combinations could facilitate the discovery of novel efficacious combinations and multi-targeted agents. In this article, we describe an extensive investigation of the published literature on drug combinations for which the combination effect has been evaluated by rigorous analysis methods and for which relevant molecular interaction profiles of the drugs involved are available. Analysis of the 117 drug combinations identified reveals general and specific modes of action, and highlights the potential value of molecular interaction profiles in the discovery of novel multicomponent therapies.

Finding multiple target optimal intervention in disease-related molecular network

Drugs against multiple targets may overcome the many limitations of single targets and achieve a more effective and safer control of the disease. Numerous high-throughput experiments have been performed in this emerging field. However, systematic identification of multiple drug targets and their best intervention requires knowledge of the underlying disease network and calls for innovative computational methods that exploit the network structure and dynamics. Here, we develop a robust computational algorithm for finding multiple target optimal intervention (MTOI) solutions in a disease network. MTOI identifies potential drug targets and suggests optimal combinations of the target intervention that best restore the network to a normal state, which can be customer designed. We applied MTOI to an inflammation-related network. The well-known side effects of the traditional non-steriodal anti-inflammatory drugs and the recently recalled Vioxx were correctly accounted for in our network model. A number of promising MTOI solutions were found to be both effective and safer.

Human metabolic network reconstruction and its impact on drug discovery and development

This paper describes the process for the reconstruction of a high quality human metabolic network from the genome information, the existing problems in the reconstruction and why a time-consuming literature based consolidation process is needed. The reconstructed metabolic network provides a unified platform to integrate all the biological and medical information on genes, proteins, metabolites, disease, drugs and drug targets for a system level study of the relationship between metabolism and disease. System analysis of metabolic networks will help us, not only in identifying new drug targets but also in developing a system-oriented drug design strategy.

Synergistic effect of formoterol and mometasone in a mouse model of allergic lung inflammation

BACKGROUND AND PURPOSE

Controversy still exists as to whether or not inhaled beta (2)-adrenoceptor agonists and corticosteroids act synergistically in vivo. In this study, we have used a murine model of lung inflammation to study the synergistic effect of an inhaled beta (2)-adrenoceptor agonist (formoterol) and an inhaled corticosteroid (mometasone).

EXPERIMENTAL APPROACH

Actively sensitized mice were challenged with aerosolized ovalbumin, once a day, for three consecutive days. Three days after the last of the three challenges, a final allergen challenge was given. Allergen-induced increase in Penh was measured 4 h after the last challenge. A day after the last challenge, increased airway sensitivity to aerosolized methacholine was demonstrated and this was concomitant with an influx of inflammatory cells in the bronchoalveolar lavage fluids.

KEY RESULTS

Mometasone (0.1 to 3 mg kg(-1)) given intranasally either an hour before or after the last allergen challenge, dose-dependently inhibited all parameters. When given intranasally either one or three hours after the last allergen challenge, but not an hour before, formoterol (1.5 to 150 microg kg(-1)) also dose-dependently inhibited most of the parameters to different degree. A synergistic effect on the allergen-induced increase in Penh was demonstrated for mometasone and formoterol given in combination, an hour after the challenge, at the following doses: mometasone/formoterol (in microg kg(-1)) 1/10, 1/100, 5/10, and 5/100.

CONCLUSIONS AND IMPLICATIONS

Our results support the hypothesis that when given as a fixed combination, inhaled corticosteroid and beta (2)-adrenoceptor agonist act synergistically in vivo.

Minimizing matrix effects in the development of a method for the determination of salmeterol in human plasma by LC/MS/MS at low pg/mL concentration levels

Salmeterol is an inhaled bronchodilator drug used for treatment of asthma. Its concentrations in plasma are very low or undetectable by previously developed methods. The present paper describes a method for analysis of salmeterol in human plasma with 2.5 pg/mL lower limit of quantitation. Despite the basic character of the drug the method uses mixed mode anion-exchange solid phase extraction for sample preparation combined with a column switching approach to minimize matrix effects. Samples are separated and detected by LC/MS/MS. The method is easy to use, only requires 0.5 mL of plasma and was validated for use in bioanalytical applications. The method does not suffer from interference from co-administered fluticasone propionate.

Zileuton added to low-dose inhaled beclomethasone for the treatment of moderate to severe persistent asthma

OBJECTIVE

To assess the therapeutic effects of oral zileuton tablets combined with low-dose beclomethasone compared to doubling the dose of beclomethasone, in improving lung function and reducing asthma symptoms.

METHODS

Randomized, active-control, double-blind, parallel, multi-center study of zileuton (400 or 600 mg QID)+200 microg beclomethasone dipropionate (BDP) BID versus placebo+BDP 400 microg BID in asthmatics with baseline FEV(1) percent predicted values between 40% and 80% following a single-blind ICS (BDP 200 microg BID) 2-week run-in. During the 3-month double-blind treatment period, assessments included safety, daytime and nighttime symptoms, acute asthma exacerbations, beta(2)-agonist use, AM and PM peak expiratory flow (PEF) and FEV(1).

RESULTS

The addition of a 5-lipoxygenase (5-LO) inhibitor added to a low-dose of BDP showed no significant difference in FEV(1) compared to doubling the dose of BDP. FEV(1) improved in all 3 treatment groups, with mean increases of 10% with zileuton 600 mg QID+BDP 200 microg BID, 12% with zileuton 400mg QID+BDP 200 microg BID, and 11% with BDP 400 microg BID by study end. Within each treatment group, there were significant improvements in asthma symptoms and AM and PM PEF compared to baseline. No significant differences were observed between groups with regards to salbutamol use, acute asthma exacerbations, the requirement for oral/parenteral corticosteroids and adverse clinical events.

CONCLUSIONS

The addition of a 5-LO inhibitor added to low-dose beclomethasone may be an alternative to higher-doses of ICS in patients unable to achieve sufficient asthma control on low-dose ICS therapy.

Adherence to a fixed-dose combination of rosiglitazone maleate/metformin hydrochloride in subjects with type 2 diabetes mellitus: a retrospective database analysis

BACKGROUND

In 2002, fixed-dose combination therapy (FDCT) with rosiglitazone maleate plus metformin hydrochloride became available for the treatment of type 2 diabetes mellitus (DM-2) in subjects whose disease was uncontrolled on monotherapy with metformin or a thiazolidinedione. FDCT allows a reduced pill burden and a less complex medication regimen.

OBJECTIVE

The objective of this study was to assess changes in medication adherence rates associated with oral hypoglycemic agents in subjects switching from either monotherapy or dual therapy with metformin and/or rosiglitazone to rosiglitazone-metformin FDCT.

METHODS

In this retrospective database analysis, data were obtained from the pharmacy claims database of a large health benefits company. Prescription claims for subjects aged > or =18 years with DM-2 whose disease was uncontrolled on monotherapy with metformin or a thiazolidinedione were analyzed over a 12-month study period (a 6-month preindex period and a 6-month postindex period). Some subjects were receiving monotherapy with either metformin or rosiglitazone during the preindex period and remained on monotherapy throughout the postindex period (Mono/Mono cohort), switched to dual therapy with both agents (Mono/Dual cohort), or switched to FDCT (Mono/FDCT cohort). Some subjects were receiving dual therapy with metformin and rosiglitazone during the preindex period and remained on dual therapy throughout the postindex period (Dual/Dual cohort) or switched to FDCT (Dual/FDCT cohort). A medication possession ratio (MPR)-a proxy measurement of medication adherence-was calculated for each subject for each period. Changes in medication adherence were compared using a general linear model.

RESULTS

Overall, data from the records of 16,928 subjects (8499 men, 8429 women; mean [SD] age, 58.12 [11.97] years) were included in this study. There was significantly less reduction in the MPR change for the Mono/FDCT cohort compared with the Mono/Dual cohort (-4.6% vs -12.4%; P < 0.001). There was significant improvement in the mean MPR change for the Dual/FDCT cohort compared with the Dual/Dual cohort (3.5% vs -1.3%; P < 0.005).

CONCLUSIONS

The results of this retrospective database analysis suggest that rosiglitazone-metformin FDCT yielded significant improvements in medication adherence rates compared with dual therapy regimens.

Asthma and therapeutics: inhaled corticosteroids, corticosteroid osteoporosis, and the risk of fracture in chronic asthma

Current guidelines for the diagnosis and treatment of osteoporosis do not address the risks to bone density and the likelihood of fracture that may be associated with inhaled corticosteroid treatment for asthma. This review outlines an approach to the use of bone densitometry in clinical practice for the diagnosis, prevention, and treatment of osteoporosis in asthmatic patients receiving inhaled corticosteroid therapy.

Cetirizine and loratadine-based antihistamines with 5-lipoxygenase inhibitory activity

A series of compounds possessing both H(1) histamine receptor antagonist and 5-lipoxygenase (5-LO) inhibitory activities was synthesized. The H(1)-binding scaffolds of cetirizine, efletirizine, and loratadine were linked to a lipophilic N-hydroxyurea, the 5-LO inhibiting moiety of zileuton. Both activities were observed in vivo, as was increased CYP3A4 inhibition compared to their respective single-function drugs. Selected analogs in the series were shown to be orally active in guinea pig models.

Differential control of TH1 versus TH2 cell responses by the combination of low-dose steroids with beta2-adrenergic agonists

BACKGROUND

Combination treatment with steroids and long-acting beta2-agonists provides greater asthma control than simply increasing the dose of steroids.

OBJECTIVE

Although the effects of combination treatment with steroids and long-acting beta2-agonists have been attributed to their anti-inflammatory and bronchodilator effects, the ability of this combination to act synergistically on T cells has not been explored.

METHODS

PBMCs from control subjects and allergic asthmatic patients were stimulated with PHA in the presence of low doses of fluticasone propionate (FP) with or without salmeterol for 72 hours. The inhibition of T-cell proliferation, cytokine production, and glucocorticoid receptor translocation was measured.

RESULTS

Both groups showed a similar degree of inhibition of PHA-induced T-cell proliferation with FP (inhibitory concentration of 50% approximately 10(-9) mol/L) alone. Use of lower concentrations of FP (10(-12) to 10(-11) mol/L) in combination with salmeterol (10(-10) to 10(-7) mol/L) in control subjects provided similar inhibition of proliferation. This combination treatment was associated with significantly greater glucocorticoid receptor translocation into the cell nucleus compared with that seen with FP alone (10(-12) mol/L; P <.01). In contrast, FP-salmeterol failed to act synergistically in asthmatic patients. The 2-drug combination significantly inhibited production of TNF-alpha and IFN-gamma in both groups (P <.05) but failed to inhibit TH2 cytokine (IL-5 and IL-13) production by PBMCs from asthmatic patients. Because allergic inflammation is associated with increased levels of cellular phosphodiesterases that might degrade salmeterol-induced cyclic adenosine monophosphate, rolipram (10(-6) mol/L), a phosphodiesterase 4 inhibitor, was added to the FP-salmeterol combination. This triple combination of drugs enhanced inhibitory activity of low-dose steroids on T-cell proliferation in asthmatic patients and inhibited IL-13 production.

CONCLUSION

These data suggest that beta2-agonists in combination with low doses of steroids can suppress T-cell proliferation and TH1 cytokine production from healthy individuals, but suppression of T cells with a combination of FP and salmeterol in asthmatic patients requires inhibition of phosphodiesterases.

Severe asthma

Severe asthma is a term that is commonly used to describe patients with refractory, brittle, near fatal, and difficult-to-control asthma. Patients with severe asthma typically experience persistent symptoms despite medical therapy, report decreased quality of life and suffer an accelerated loss of lung function. The role of genetics, environmental exposure, and infection in the development of more severe asthma is the focus of ongoing research. While pathologic changes in these patients are now believed to involve lung parenchyma, in addition to large and small airways, the independent contribution of each of these compartments to the severe asthma phenotype is not well defined. The clinical evaluation of severe asthma patients should include investigating conditions commonly associated with severe asthma, such as gastroesophageal reflux disease, vocal cord dysfunction, and rhinosinusitis. In addition, advanced imaging techniques, measurement of exhaled gas or sputum indices, and airway biopsy are tools that may aid in evaluating severe asthma patients in the near future. Management of patients with severe asthma requires a comprehensive approach that includes non-pharmacological and pharmacological measures. Combination antiinflammatory and long-acting bronchodilator therapy remains the mainstay of management.

[Pulmonary diseases in the elderly. Problems of pharmacotherapy]

In asthma, inhaled corticosteroids (ICS) can be regarded as disease-modifying drugs. They represent the mainstay of pharmacotherapy of asthma. In elderly, ICS are currently underused. In chronic obstructive pulmonary disease (COPD), there is recent evidence to suggest that ICS may reduce the rate and severity of COPD exacerbations and may improve health-related quality of life. Particularly patients with moderate-to-severe COPD appear to benefit from ICS therapy. In both asthma and COPD, fixed combinations of ICS and long-acting beta 2-agonists may provide clinically meaningful benefits to patients and may represent a further therapeutic advantage.

Targeting the issues in chronic obstructive lung disease

Chronic obstructive pulmonary disease (COPD) is a disease of unclear aetiology and variable pathology among patients. Little is known about the cellular mechanisms which cause this condition and, although the incidence of COPD has been rising worldwide for some time, research efforts have only very recently increased. Medication thus far has focused on symptom treatment rather than targeting identifiable disease mechanisms. Such treatment has consisted primarily of bronchodilators, both beta-agonists and anticholinergic in action. Treatment with steroids has been disappointing, except in the case of acute exacerbation, and this has shifted the research focus to characterising the inflammatory process in COPD as distinct from that in asthma. New targets for pharmacotherapy are coming to light as information is gained about specific inflammatory mediators active in COPD and the role of oxidative stress in this disease. In addition, new approaches include describing the role of exogenous antiproteases in restoring the balance between protease-antiprotease mechanisms that may be defective in this disease. Ultimately, exploration of the molecular genetics of COPD will provide new targets for future pharmacological agents.

Improved ability to perform strenuous activities after treatment with fluticasone propionate/salmeterol combination in patients with persistent asthma

Patients with asthma experience disruptions in usual activities that can impair their quality of life, and in patients whose daily routine involves an active lifestyle, these disruptions can be severe. We assessed the patient-perceived effect of treatment with fluticasone propionate/salmeterol combination (FSC), compared with fluticasone propionate (FP) or salmeterol (SAL) alone, on activity limitations, particularly strenuous physical activities. The Asthma Quality of Life Questionnaire (AQLQ) was administered in two 12-week, randomized, double-blind, placebo-controlled trials comparing FSC 100/50 or 250/50 microg twice daily vs. the individual components alone in 686 adults and adolescents with asthma. In one study, patients were stratified by prior treatment [low to medium doses of inhaled corticosteroids (ICS) or SAL], and in the other study, all patients were previously treated with medium to high doses of ICS. Patients prospectively identified five activities they performed regularly and were asked how these activities were limited by their asthma. The effect of randomized treatment on strenuous activities (e.g., aerobics, cycling, hiking, and basketball) was assessed. In both studies, treatment with FSC resulted in clinically meaningful improvements (i.e., change in AQLQ of > or = 0.5) and was statistically significantly better than SAL in both studies and FP in one study. Treatment of the two main components of asthma--inflammation and bronchoconstriction--with FSC results in clinically meaningful improvements in the ability of patients with persistent asthma to perform not only their usual activities but also strenuous activities.

Concomitant occasional use of salbutamol influences bronchoprotective responsiveness afforded by formoterol in patients with the glycine-16 genotype

BACKGROUND

Predisposition to subsensitivity with long-acting beta(2)-agonists (LABA) or regular short-acting beta(2)-agonists (SABA) is related to polymorphisms at codon 16 of the beta(2)-adrenoceptor.

OBJECTIVE

To determine whether the use of occasional SABA induces further baseline downregulation of the beta(2)-adrenoceptor to that of endogenous catecholamines alone, in Gly-16 patients.

METHODS

A post-hoc analysis of two studies was performed. Twenty-three homozygous Gly-16 asthmatic patients received 12 microg inhaled formoterol either o.d. or b.i.d. for 2 weeks. Patients had been supplied with ipratropium bromide (IB) to use as reliever therapy preferentially over salbutamol. Spirometry and adenosine monophosphate (AMP) bronchial challenge was performed after 7-14 days of placebo and after active treatment.

RESULTS

A review of domiciliary diary card data indicated 13 patients (mean FEV(1): 76.8% pred., AMP PC(20): 23.4 mg/ml) did not require salbutamol, and 10 patients (mean FEV(1): 77.9% pred., AMP PC(20): 27.9 mg/ml) required occasional salbutamol (1.67 puffs/day) during run-in and/or formoterol periods. No significant difference in spirometry or AMP PC(20) were found between the populations after placebo. After formoterol, compared with placebo, patients requiring occasional salbutamol had no improvement in AMP PC(20) [geometric mean PC(20) (and 95% CI): 28.0 mg/ml (20.5-38.4) versus 34.46 mg/ml (25.1-47.3)], while those patients not requiring salbutamol had a significant ( p<0.05) improvement in AMP PC(20) with formoterol compared with placebo [89.9 mg/ml (52.4-154.3) versus 30.6 mg/ml (17.8-52.5)]. This amounted to a 3.12-fold (95% CI: 0.16-6.07) geometric mean fold difference between groups.

CONCLUSIONS

Our results indicate that homozygous Gly-16 patients using occasional salbutamol have reduced responsiveness to formoterol in terms of bronchoprotection to AMP than patients not using salbutamol. Patients expressing the homozygous gly-16 genotype of the beta(2)-adrenoceptor genotype receiving a LABA may benefit from the substitution of their usual SABA for an alternative reliever.

Combination therapy: appropriate for everyone?

The severity of asthma often varies throughout the course of the disease. At times the symptoms and underlying inflammation that are characteristic of asthma can worsen. Thus during an episode of viral-induced asthma or during a seasonal increase in asthma severity, a patient may be directed to increase his or her dosage of asthma controllers (i.e., inhaled corticosteroid) or add a long-acting bronchodilator (or other controller medications such as antileukotrienes) to manage symptoms, as recommended in guidelines published by the National Institutes of Health (NIH). Similarly, when symptoms are stable, decreasing dosages or discontinuing certain medications may be appropriate. The recent introduction of a combination product, of a long-acting bronchodilator formulated in the same dry powder device with an inhaled corticosteroid raises new challenges for the step care approach to asthma management recommended by the NIH in 1997. Although unquestionably more convenient for the patient, a combination formulation has the potential to decrease the flexibility required to successfully manage asthma over long periods. In addition, controversy exists regarding long-acting beta-agonists alone because their regular use may mask inflammation in the lung and decrease responsiveness to the bronchodilating effects of rescue medications (i.e., short-acting beta-agonists). The purpose of this article is to help physicians make informed therapeutic decisions for their patients with asthma. It focuses on the advantages and potential disadvantages of using combination products, which contain both an inhaled corticosteroid and a long-acting beta-agonist in the context of the NIH step care approach. Recent publications outlining the use of other add-on controller medications are also discussed.

Inhaled corticosteroids in chronic obstructive pulmonary disease: new trials and old practices

The practice of using inhaled steroids (ICS) in chronic obstructive pulmonary disease (COPD) is common but controversial. Four large randomized controlled trials provide an objective assessment of this practice. An examination of the design of these studies is useful to explaining some of the differences between their results but may also help to appropriately integrate the findings of these studies into clinical practice. All studies agree that the early introduction of the inhaled corticosteroids (ICS) does not appear to affect the rate of decline in FEV1. Thus, the routine prescription of these agents to asymptomatic patients with well-preserved lung function is not indicated. However, more selective use of ICS in patients with moderately severe disease (FEV1 < 50% predicted) may produce clinical benefit as measured by an increase in FEV1, reduced symptoms and fewer exacerbations. The effectiveness of ICS in patients with severe disease (FEV < 800 mL, or chronic respiratory failure) has not been studied due to practical difficulties of enrolling and maintaining such patients in clinical trials. Similarly patients with evidence of chronic bronchitis and emphysema who demonstrate high degrees of reversibility (>10% predicted FEV1) are usually excluded from both COPD and asthma trials, and the effectiveness of ICS in this population is also not known. Neither responsiveness to a single dose of beta(2)-agonist nor to a 14-day trial of systemic steroids has been shown to be a reliable predictor of response to ICS. For individual patients with moderate or severe symptomatic COPD, an 8-week therapeutic trial with ICS may be needed to assess clinical benefit.

Inhaled salmeterol/fluticasone propionate combination: a pharmacoeconomic review of its use in the management of asthma

Asthma guidelines recommend an inhaled corticosteroid plus a long-acting inhaled beta(2)-agonist (beta(2)-adrenoceptor agonist) as the preferred maintenance therapy for moderate and severe persistent asthma. Advair/Seretide Diskus also registered as Accuhaler is fixed-dose salmeterol (a long-acting inhaled beta(2)-agonist) and fluticasone propionate (a corticosteroid) administered via a single powder inhalation device. The clinical effectiveness of salmeterol/fluticasone propionate in patients with persistent asthma symptoms has been established in comparative clinical trials. Pharmacoeconomic analyses, based on data from these clinical trials, have been conducted from a healthcare payer perspective in various countries. In patients with asthma not controlled with inhaled corticosteroids, salmeterol/fluticasone propionate was associated with more favourable (lower) cost-effectiveness ratios than fluticasone propionate monotherapy, oral montelukast plus inhaled fluticasone propionate, inhaled budesonide, and inhaled formoterol plus budesonide. As the initial maintenance therapy in patients with persistent asthma symptoms while receiving short-acting beta(2)-agonists alone, salmeterol/fluticasone propionate was cost effective relative to montelukast monotherapy. Although the total cost of asthma management tended to be slightly higher with salmeterol/fluticasone propionate than with fluticasone propionate or montelukast monotherapy, salmeterol/fluticasone propionate consistently had a more favourable cost-effectiveness ratio in terms of per successfully treated week or symptom-free day and/or was associated with small incremental costs to achieve significant additional clinical benefits. In clinical practice, salmeterol plus fluticasone propionate was associated with lower asthma-related costs than treatment with other maintenance therapies.In patients with asthma symptoms despite treatment with inhaled corticosteroids, salmeterol/fluticasone propionate produced clinically meaningful improvements in overall Asthma Quality of Life Questionnaire (AQLQ) scores relative to salmeterol or placebo monotherapy, in emotional function domain scores relative to fluticasone propionate or budesonide, and in asthma symptoms domain scores relative to budesonide. In patients with persistent asthma symptoms while receiving short-acting beta(2)-agonists alone, salmeterol/fluticasone propionate produced clinically meaningful improvements in overall AQLQ scores compared with fluticasone propionate or montelukast.

CONCLUSIONS

Pharmacoeconomic analyses indicate that salmeterol/fluticasone propionate administered via a single inhaler represents a cost-effective treatment option (relative to fluticasone propionate at the same nominal dosage, budesonide, formoterol plus budesonide and montelukast plus fluticasone propionate) in patients with asthma not controlled with inhaled corticosteroid therapy. In patients with asthma not controlled with short-acting beta(2)-agonists alone, salmeterol/fluticasone propionate is a cost effective treatment relative to monotherapy with montelukast. Importantly, salmeterol/fluticasone propionate is also associated with improvements in health-related quality of life.

Update on glucocorticoid action and resistance

Glucocorticoids (GCs) are the most common group of medications used in the treatment of allergic and autoimmune disorders. They produce potent anti-inflammatory effects by inducing or repressing the expression of target genes. Although most patients with allergic diseases and autoimmune disorders respond to GC therapy, a small subset of patients demonstrate persistent tissue inflammation despite treatment with high doses of GCs. This condition results from an interaction between susceptibility genes, the host's environment, and immunologic factors. The treatment of these patients requires a systematic approach to rule out underlying conditions that lead to steroid resistance or treatment failure, as well as the use of alternative strategies to inhibit tissue inflammation.

The use of inhaled corticosteroids in children with asthma

The inhaled corticosteroids (ICSs) are the most effective long-term controllers for the treatment of childhood asthma. There is now substantial controlled clinical trial data to support the efficacy and safety of ICS therapy in infants and young children (6 months to 4 years of age). These data support the use of nebulizer suspension or metered-dose inhalers with valved holding chambers as effective forms of delivery in this age group. Currently, selection of delivery method depends on the comfort of the parent and the cooperation of the child, as well as on which drug the clinician chooses. The ICSs have a favorable safety profile when administered in currently recommended dosages. A transient 0.5- to 2-cm growth delay occurs in prepubescent children but does not appear to affect attainment of predicted adult height. Long-term trials support the existing recommendations of lowering dosage once control is achieved and stopping therapy when the child's asthma is in remission.