American Lung Association Asthma Clinical Research Centers. Clinical trial of low-dose theophylline and montelukast in patients with poorly controlled asthma

Asthma outcomes: symptoms

BACKGROUND

Respiratory symptoms are commonly used to assess the impact of patient-centered interventions.

OBJECTIVE

At the request of National Institutes of Health (NIH) institutes and other federal agencies, an expert group was convened to propose which measurements of asthma symptoms should be used as a standardized measure in future clinical research studies.

METHODS

Asthma symptom instruments were classified as daily diaries (prospectively recording symptoms between research visits) or retrospective questionnaires (completed at research visits). We conducted a systematic search in PubMed and a search for articles that cited key studies describing development of instruments. We classified outcome instruments as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an NIH-organized workshop in March 2010 and finalized in September 2011.

RESULTS

Four instruments (3 daily diaries, 1 for adults and 2 for children; and 1 retrospective questionnaire for adults) were identified. Minimal clinically important differences have not been established for these instruments, and validation studies were only conducted in a limited number of patient populations. Validity of existing instruments may not be generalizable across racial-ethnic or other subgroups.

CONCLUSIONS

An evaluation of symptoms should be a core asthma outcome measure in clinical research. However, available instruments have limitations that preclude selection of a core instrument. The working group participants propose validation studies in diverse populations, comparisons of diaries versus retrospective questionnaires, and evaluations of symptom assessment alone versus composite scores of asthma control.

Pharmacogenetics of asthma controller treatment

The interpatient variability in response to asthma controllers is significant and associates with pharmacogenomic variability. The goal of the present study was to identify novel variants that associate with response to common asthma controllers: fluticasone, combination of fluticasone + salmeterol and montelukast with single nucleotide polymorphisms (SNPs) in β2-adrenergic receptor, corticosteroid and leukotriene pathway candidate genes. Participants in a large clinical trial of step-down strategies volunteered for this pharmacogenetic study. A total of 169 SNPs in 26 candidate genes were genotyped in 189 Caucasian participants with asthma who took either fluticasone (100 μg bid), fluticasone propionate (100 μg) + salmeterol (50 μg) (FP/Salm) or montelukast (5 or 10 mg) each night for 16 weeks. Primary outcomes were the slopes of plots of Asthma Control Questionnaire (ACQ) scores versus time following randomization; and the percent change in percent predicted FEV1 (ΔFEV1%pred) from enrollment to the end of the study. Associations between SNPs and outcomes were analyzed using general linear models. False discovery rate and Bonferroni corrections were used to correct for multiple comparisons. In all, 16 SNPs in seven genes were significantly associated with outcomes. For FP/Salm, three SNPs in CHRM2 associated with ACQ slope (P=2.8 × 10⁻⁵), and rs1461496 in HSPA8 associated with ΔFEV1%pred. For fluticasone, five SNPs in CRHR1 (P=1.9 × 10⁻⁴), and three SNPs in COL2A1 associated with ACQ slope and ΔFEV1%pred, respectively. For montelukast, four SNPs in CHRM2 associated with ΔFEV1%pred and predicted an opposite effect compared with fluticasone (P=9 × 10⁻³). The present study indentified several novel SNPs that associate with response to common asthma controllers, and support further pharmacogenomic study and the use of genetic variants to personalize asthma treatment.

Nocturnal asthma

PURPOSE OF REVIEW

The aim is to review pathophysiological mechanisms and treatment of nocturnal asthma.

RECENT FINDINGS

Physiologic changes accompanying sleep, as well as the nocturnal phase of circadian rhythms, may have an adverse effect on asthma control. Chronotherapeutic principles, which consider circadian variation in relevant biologic rhythms, may improve asthma outcomes. Administration of long-acting bronchodilators and inhaled corticosteroids which achieve maximum efficacy at night may improve nocturnal asthma. Comorbid conditions that may contribute to nocturnal asthma should be considered. The prevalence of obstructive sleep apnea is greater in a cohort of patients with severe asthma than in moderate asthma and in BMI and age matched nonasthmatic controls, suggesting a link between these diseases. A large trial concluded that esomeprazole did not improve asthma control even with comorbid acid reflux, questioning the importance of acid reflux in asthma. The role of polymorphisms of the β2-adrenergic receptor and their relationship with nocturnal asthma remain controversial.

SUMMARY

Sleep is a time of vulnerability to respiratory compromise, especially in asthma patients experiencing nocturnal exacerbations. This asthma phenotype is associated with poorer control, reduced sleep quality, daytime somnolence and increased morbidity and mortality. Nocturnal asthma is a common but under-recognized problem.

Achieving symptom control in patients with moderate asthma

Disease severity in asthma can be classified as mild, moderate or severe based upon the frequency of symptoms or the severity of airflow obstruction. This review will focus on the treatment of youths greater than 12 years of age and adults with moderate persistent asthma. Moderate asthmatics may have daily symptoms that cause some limitation with normal daily activities and require use of a rescue inhaled short-acting beta(2)-agonist inhaler or experience nocturnal awakenings secondary to asthma that occur more than once per week. Furthermore, spirometry may reveal airflow obstruction with a reduction in FEV(1) to between 60% and 80% of predicted. Although inhaled corticosteroids (ICS) are the primary controller medication used to modify symptoms in moderate asthmatics, additional controller medications, such as inhaled long-acting beta(2)-agonists (LABA), leukotriene receptor antagonists (LTRA) or theophylline, are often needed to obtain optimal disease control. While the addition of an inhaled LABA to an ICS is very effective at improving disease control in moderate asthma, concerns have arisen over the safety of LABAs, in particular the risk of asthma-related death. Therefore, consideration may be given to initially adding a LTRA, rather than a LABA, to ICS when asthma symptoms are not adequately controlled by ICS alone. Furthermore, individualization of medication regimens, treatment of co-morbid conditions, and patient education are crucial to optimizing compliance with therapy, improving disease control, and reducing the risk of exacerbations. Lastly, the development of new asthma treatments, perhaps based upon personalized medicine, may revolutionize the future treatment of moderate asthma.

Identifying and testing potential new anti-asthma agents

INTRODUCTION

Inhaled corticosteroids alone or with long-acting beta-2 agonists (LABA) are the basic treatment for stable asthma. While the majority of patients are controllable, some patients retain chronic severe disease and develop permanent alterations in airway function. For patients such as these it is important to better understand the mechanisms of asthma so that alternative approaches can be developed.

AREA COVERED

Based on data from in vitro cell culture, animal models and clinical trials, this review discusses potential agents targeting either key effector cells, mediators and their receptors in asthma pathogenesis or their signaling cascade molecules.

EXPERT OPINION

As targeting single Th2 cytokines and their receptors has been shown to have limited clinical benefit, it is important to identify and test potential new therapeutic agents. Recent studies suggest that blockade of IgE synthesis, its interaction with its receptors and downstream signaling, identification of molecular targets in innate immune and airways structural cells, and fresh anti-neutrophil strategies should be prominent among these. Further studies are required to clarify the relationship between airways remodeling and asthma severity so that appropriate patients may be targeted.

[Montelukast in the treatment of mild to moderate persistent asthma]

INTRODUCTION

Anti-inflammatory preventive treatment is recommended in cases of persistent asthma. Besides inhaled corticosteroids (ICS), which represent the mainstay of treatment, other therapeutic options are available, of which only antileukotrienes are approved for all age groups.

BACKGROUND

Given as a substitute of low-dose ICS, montelukast prevents exacerbations as efficiently and for a longer period than long-acting β2-agonists. Montelukast is as efficient as doubling the dose of ICS on asthma symptoms in cases of inadequate control with low-dose ICS. Combined with ICS, it can lead to better control of asthma and potentially to ICS sparing.

CONCLUSIONS

Given the efficacy, tolerance and long-term treatment compliance of montelukast in mild persistent asthma in adults and children, montelukast, given as a substitute or combined with ICS, could contribute to enhanced control of asthma, especially in children.

Omalizumab in severe allergic asthma inadequately controlled with standard therapy: a randomized trial

BACKGROUND

Inhaled corticosteroids (ICS) and long-acting β(2)-agonists (LABAs) are recommended in patients with asthma that is not well-controlled; however, many patients continue to have inadequately controlled asthma despite this therapy.

OBJECTIVE

To evaluate the efficacy and safety of omalizumab in patients with inadequately controlled severe asthma who are receiving high-dose ICS and LABAs, with or without additional controller therapy.

DESIGN

Prospective, multicenter, randomized, parallel-group, double-blind, placebo-controlled trial. (ClinicalTrials.gov registration number: NCT00314575).

SETTING

193 investigational sites in the United States and 4 sites in Canada.

PATIENTS

850 patients aged 12 to 75 years who had inadequately controlled asthma despite treatment with high-dose ICS plus LABAs, with or without other controllers.

INTERVENTION

Omalizumab (n = 427) or placebo (n = 423) was added to existing medication regimens for 48 weeks.

MEASUREMENTS

The primary end point was the rate of protocol-defined exacerbations over the study period. Secondary efficacy end points included the change from baseline to week 48 in mean daily number of puffs of albuterol, mean total asthma symptom score, and mean overall score on the standardized version of the Asthma Quality of Life Questionnaire (AQLQ[S]). Safety end points included the frequency and severity of treatment-emergent adverse events.

RESULTS

During 48 weeks, the rate of protocol-defined asthma exacerbations was significantly reduced for omalizumab compared with placebo (0.66 vs. 0.88 per patient; P = 0.006), representing a 25% relative reduction (incidence rate ratio, 0.75 [95% CI, 0.61 to 0.92]). Omalizumab improved mean AQLQ(S) scores (0.29 point [CI, 0.15 to 0.43]), reduced mean daily albuterol puffs (-0.27 puff/d [CI, -0.49 to -0.04 puff/d]), and decreased mean asthma symptom score (-0.26 [CI, -0.42 to -0.10]) compared with placebo during the 48-week study period. The incidence of adverse events (80.4% vs. 79.5%) and serious adverse events (9.3% vs. 10.5%) were similar in the omalizumab and placebo groups, respectively.

LIMITATIONS

The results are limited by early patient discontinuation (20.8%). The study was not powered to detect rare safety events or the treatment effect in the oral corticosteroid subgroup.

CONCLUSION

In this study, omalizumab provided additional clinical benefit for patients with severe allergic asthma that is inadequately controlled with high-dose ICS and LABA therapy.

PRIMARY FUNDING SOURCE

Genentech and Novartis Pharmaceuticals.

Asthma in sickle cell disease: implications for treatment

Objective. To review issues related to asthma in sickle cell disease and management strategies. Data Source. A systematic review of pertinent original research publications, reviews, and editorials was undertaken using MEDLlNE, the Cochrane Library databases, and CINAHL from 1947 to November 2010. Search terms were [asthma] and [sickle cell disease]. Additional publications considered relevant to the sickle cell disease population of patients were identified; search terms included [sickle cell disease] combined with [acetaminophen], [pain medications], [vitamin D], [beta agonists], [exhaled nitric oxide], and [corticosteroids]. Results. The reported prevalence of asthma in children with sickle cell disease varies from 2% to approximately 50%. Having asthma increases the risk for developing acute chest syndrome , death, or painful episodes compared to having sickle cell disease without asthma. Asthma and sickle cell may be linked by impaired nitric oxide regulation, excessive production of leukotrienes, insufficient levels of Vitamin D, and exposure to acetaminophen in early life. Treatment of sickle cell patients includes using commonly prescribed asthma medications; specific considerations are suggested to ensure safety in the sickle cell population. Conclusion. Prospective controlled trials of drug treatment for asthma in patients who have both sickle cell disease and asthma are urgently needed.

Theophylline inhibits the differentiation of human monocyte into dendritic cell potentially via adenosine receptor antagonism

BACKGROUND

Theophylline has an anti-inflammatory action that may account for its clinical effectiveness in the reduction of inflammatory cells in the airways. Dendritic cells (DCs) are professional antigen-presenting cells, capable of priming naïve T cells, and play key roles in the activation of immune responses in asthma.

OBJECTIVE

The purpose of this study was to investigate the effects of theophylline on human monocyte differentiation into DCs and whether this involved antagonism of adenosine receptors.

METHODS

Peripheral human blood monocytes were cultured in the presence of granulocyte/macrophage-colony stimulating factor and IL-4 to induce DC differentiation. The cells were incubated with theophylline, KF17837 (a selective A2a receptor antagonist) and enprofylline (A2b receptor antagonist) and co-incubated with selective adenosine A1 and A2a receptor agonists, a phosphodiesterase inhibitor (rolipram) and adenosine deaminase (ADA) to determine their effects on DC differentiation. In addition, depletion of adenosine receptors by small interfering RNA (siRNA) was also examined.

RESULTS

Monocytes differentiated into myeloid DCs in the culture system. The number of DCs was remarkably reduced by 60-70% when theophylline was administered at a therapeutic concentration. This effect was concentration-dependently exacerbated, was partly mediated by cellular apoptosis and was effectively reversed by the addition of the A1 agonists [2-chloro-N(6)-cyclopentyladenosin, N(6)-cyclohexyladenosine, and N-ethylcarboxamidoadenosine (NECA)] or the A2a agonist (CGS-21680, NECA). The depletion of the adenosine A1 receptor by siRNA and addition of ADA remarkably reduced DC differentiation. Meanwhile, both enprofylline and rolipram had little effect.

CONCLUSION

Our findings suggest that the adenosine A1 (and possibly coordinated with A2a) receptors contribute to DC differentiation and survival. These findings provide further evidence that theophylline has an anti-inflammatory action in bronchial asthma.

Development of a Pharmacogenetic Predictive Test in asthma: proof of concept

OBJECTIVE

To assess the feasibility of developing a Combined Clinical and Pharmacogenetic Predictive Test, comprised of multiple single nucleotide polymorphisms (SNPs) that is associated with poor bronchodilator response (BDR).

METHODS

We genotyped SNPs that tagged the whole genome of the parents and children in the Childhood Asthma Management Program (CAMP) and implemented an algorithm using a family-based association test that ranked SNPs by statistical power. The top eight SNPs that were associated with BDR comprised the Pharmacogenetic Predictive Test. The Clinical Predictive Test was comprised of baseline forced expiratory volume in 1 s (FEV1). We evaluated these predictive tests and a Combined Clinical and Pharmacogenetic Predictive Test in three distinct populations: the children of the CAMP trial and two additional clinical trial populations of asthma. Our outcome measure was poor BDR, defined as BDR of less than 20th percentile in each population. BDR was calculated as the percent difference between the prebronchodilator and postbronchodilator (two puffs of albuterol at 180 microg/puff) FEV1 value. To assess the predictive ability of the test, the corresponding area under the receiver operating characteristic curves (AUROCs) were calculated for each population.

RESULTS

The AUROC values for the Clinical Predictive Test alone were not significantly different from 0.50, the AUROC of a random classifier. Our Combined Clinical and Pharmacogenetic Predictive Test comprised of genetic polymorphisms in addition to FEV1 predicted poor BDR with an AUROC of 0.65 in the CAMP children (n = 422) and 0.60 (n = 475) and 0.63 (n = 235) in the two independent populations. Both the Combined Clinical and Pharmacogenetic Predictive Test and the Pharmacogenetic Predictive Test were significantly more accurate than the Clinical Predictive Test (AUROC between 0.44 and 0.55) in each of the populations.

CONCLUSION

Our finding that genetic polymorphisms with a clinical trait are associated with BDR suggests that there is promise in using multiple genetic polymorphisms simultaneously to predict which asthmatics are likely to respond poorly to bronchodilators.

[When and how to modify the management of asthma in children over the age of 4]

The treatment of asthma in children should not be fixed but rather must be regularly adapted to keep the condition under control defined according to clinical and functional criteria. In a child whose asthma is controlled, a step down in therapy should be carried out every 3 to 6 months to achieve the minimal effective level of treatment. In a child whose asthma appears not to be controlled, it is necessary initially to evaluate compliance with therapy and to seek aggravating factors which may include allergic rhinitis, multiple sensitisation, tobacco exposure, psychological factors, obesity, gastro- oesophageal reflux and infection. Where control of asthma is poor the main therapeutic strategy rests on an increase in the dose of inhaled corticosteroid and on the addition of other anti-asthmatic treatments--inhaled long--acting beta 2 agonists and oral leukotriene antagonists.

Therapeutic targets for persistent airway inflammation in refractory asthma

The management of refractory asthma remains a compelling clinical problem that contributes significantly to the morbidity of patients as well as posing a financial burden to the health system. Treatment failure in this group of patients is associated with continued airway inflammation and dampening of the inflammatory cascade is the focus of much research in this area. Continued airway inflammation has been associated with higher patient morbidity and is being increasingly measured using markers of systemic and local inflammation in order to target therapy more effectively. This review focuses on the published evidence for both established and novel treatments in refractory asthma that act to control this pathological inflammatory process. No clear treatment yet exists to control this process and further research into inhibiting newly elucidated inflammatory pathways or new drugs more effectively or accurate targeting existing pathways are discussed along with the clinical evidence and the relative merits of each treatment.

Predictors of asthma control in everyday clinical practice in Switzerland

OBJECTIVE

To identify predictors of improved asthma control under conditions of everyday practice in Switzerland.

RESEARCH DESIGN AND METHODS

A subgroup of 1380 patients with initially inadequately controlled asthma was defined from a cohort of 1893 asthmatic patients (mean age 45.3 + or - 19.2 years) recruited by 281 office-based physicians who participated in a previously-conducted asthma control survey in Switzerland. Multiple regression techniques were used to identify predictors of improved asthma control, defined as an absolute decrease of 0.5 points or more in the Asthma Control Questionnaire between the baseline (V1) and follow-up visit (V2).

RESULTS

Asthma control between V1 and V2 improved in 85.7%. Add-on treatment with montelukast was reported in 82.9% of the patients. Patients with worse asthma control at V1 and patients with good self-reported adherence to therapy had significantly higher chances of improved asthma control (OR = 1.24 and 1.73, 95% CI 1.18-1.29 and 1.20-2.50, respectively). Compared to adding montelukast and continuing the same inhaled corticosteroid/fixed combination (ICS/FC) dose, the addition of montelukast to an increased ICS/FC dose yielded a 4 times higher chance of improved asthma control (OR = 3.84, 95% CI 1.58-9.29). Significantly, withholding montelukast halved the probability of achieving improved asthma control (OR = 0.51, 95% CI = 0.33-078). The probability of improved asthma control was almost 5 times lower among patients in whom FEV(1) was measured compared to those in whom it was not (OR = 0.23, 95% CI = 0.09-0.55). Patients with severe persistent asthma also had a significantly lower probability of improved control (OR = 0.15, 95% CI = 0.07-0.32), as did older patients (OR = 0.98, 95% CI = 0.97-0.99). Subgroup analyses which excluded patients whose asthma may have been misdiagnosed and might in reality have been chronic obstructive pulmonary disease (COPD) showed comparable results.

CONCLUSIONS

Under conditions of everyday clinical practice, the addition of montelukast to ICS/FC and good adherence to therapy increased the likelihood of achieving better asthma control at the follow-up visit, while older age and more severe asthma significantly decreased it.

Measuring asthma control is the first step to patient management: a literature review

Asthma control is recognized as a critical aspect of the evaluation and management of the disease. Here we evaluate and compare existing instruments for measuring asthma control in an attempt to evaluate their clinical utility. Based on a literature review, we identified validated instruments used to assess asthma control in adults. We examined the specific measurement properties and the strengths and weaknesses of each instrument, and evaluated a single instrument, the Asthma Control Questionnaire (ACQ), more closely as an example, evaluating its applicability in the clinical setting. Our review identified five validated instruments designed to measure asthma control: the Asthma Control Questionnaire (ACQ), Asthma Control Scoring System (ACSS), Asthma Control Test (ACT), Asthma Therapy Assessment Questionnaire (ATAQ), and the Lara Asthma Symptom Scale (LASS). None of the instruments covered all relevant control characteristics, but most were aligned with guideline definitions of control. All instruments demonstrated validity and responsiveness, with some measure of reliability. All instruments were short and easily administered, easy to interpret, and all had evidence to support their use in clinical decision making.

Pharmacogenetics and functional genomics in asthma

Asthma is a complex phenotype caused by a combination of genetic and environmental factors that remain poorly understood. The common variants involved in the pathogenesis of asthma have proved difficult to identify by candidate gene association studies. As a result, few genetic variants influencing clinical response to asthma and allergy medications have been uncovered. Recently, genome-wide association, which is more robust in identifying common predisposition variants, has been applied to disorders such as asthma. As genome-wide associations are hypothesis-free, they raise the possibility of identifying novel biological pathways that could be translated to the future benefit of patients through improved diagnostic and therapeutic measures in the form of personalized medicine. This review addresses both recent advances in the genetics of asthma and their potential in transforming the treatment of the disorder into more individualized care in the near future.

Efficacy of esomeprazole for treatment of poorly controlled asthma

BACKGROUND

Gastroesophageal reflux is common among patients with asthma but often causes mild or no symptoms. It is not known whether treatment of gastroesophageal reflux with proton-pump inhibitors in patients who have poorly controlled asthma without symptoms of gastroesophageal reflux can substantially improve asthma control.

METHODS

In a parallel-group, double-blind trial, we randomly assigned 412 participants with inadequately controlled asthma, despite treatment with inhaled corticosteroids, and with minimal or no symptoms of gastroesophageal reflux to receive either 40 mg of esomeprazole twice a day or matching placebo. Participants were followed for 24 weeks with the use of daily asthma diaries, spirometry performed once every 4 weeks, and questionnaires that asked about asthma symptoms. We used ambulatory pH monitoring to ascertain the presence or absence of gastroesophageal reflux in the participants. The primary outcome was the rate of episodes of poor asthma control, as assessed on the basis of entries in asthma diaries.

RESULTS

Episodes of poor asthma control occurred with similar frequency in the placebo and esomeprazole groups (2.3 and 2.5 events per person-year, respectively; P=0.66). There was no treatment effect with respect to individual components of the episodes of poor asthma control or with respect to secondary outcomes, including pulmonary function, airway reactivity, asthma control, symptom scores, nocturnal awakening, or quality of life. The presence of gastroesophageal reflux, which was documented by pH monitoring in 40% of participants with minimal or no symptoms, did not identify a subgroup of patients that benefited from treatment with proton-pump inhibitors. There were fewer serious adverse events among patients receiving esomeprazole than among those receiving placebo (11 vs. 17).

CONCLUSIONS

Despite a high prevalence of asymptomatic gastroesophageal reflux among patients with poorly controlled asthma, treatment with proton-pump inhibitors does not improve asthma control. Asymptomatic gastroesophageal reflux is not a likely cause of poorly controlled asthma. (ClinicalTrials.gov number, NCT00069823.)

Absorption of montelukast is transporter mediated: a common variant of OATP2B1 is associated with reduced plasma concentrations and poor response

OBJECTIVES

To (i) determine whether montelukast undergoes carrier-mediated uptake; (ii) classify the carrier protein(s) responsible for uptake; (iii) identify specific transporters that mediate transport of montelukast; and (iv) evaluate whether variation in the gene encoding the transport protein(s) influences the pharmacokinetics and pharmacodynamics of montelukast.

METHODS

In-vitro permeability studies of montelukast are carried out using Caco-2 cell culture, a standard model of human intestinal drug transport. In-vivo plasma concentrations of montelukast in an asthmatic population are determined by high-performance liquid chromatography, and genotyping of transport proteins is by LightTyper analysis.

RESULTS

Permeability of montelukast has an activation energy of 13.7+/-0.7 kcal/mol, consistent with carrier-mediated transport. Permeability is saturable at high concentrations of montelukast and follows Michaelis-Menten kinetics. Permeability is subject to competition by sulfobromophthalein, estrone-3-sulfate, pravastatin, taurocholic acid, and cholic acid (P<0.05, percentage of control: 72+/-7-86+/-7) and is inhibited by 5-10% citrus juice (P<0.05, maximal inhibition percentage of control: 31+/-2). An MDCKII cell line expressing OATP2B1 (coded for by the SLCO2B1 gene) displays significantly increased permeability of montelukast (P<0.05, percentage of control: 140+/-20). A nonsynonymous polymorphism in SLCO2B1, rs12422149; SLCO2B1 {NM_007256.2}:c.935G>A, associates with significantly reduced plasma concentration in patients measured on the morning after an evening dose (P<0.025, square root mean transformed plasma concentration+/-SE; c.[935G>A]+[935G]=3+/-1, c.[935G]+[935G]=7.0+/-0.9) and differential response as assessed by change in baseline Asthma Symptom Utility Index scores after 1 month of therapy (delta mean Asthma Symptom Utility Index; c.[935G>A]+[935G]=0.02+/-0.01, P=1.0; c.[935G]+[935G]=1.0+/-0.3, P<0.0001).

CONCLUSION

Altogether, these observations suggest that the genetics of SLCO2B1 may be an important variable in determining the pharmacokinetics and the pharmacodynamics of montelukast.

[Guideline-adherent treatment for asthma]

Asthma is a complex syndrome with numerous clinical phenotypes. An increase in prevalence is detectable worldwide. Efforts to optimize diagnosis and care of patients with asthma have led to the development of international and national guidelines. Besides preventive and non-pharmacological measures such as patient education and physical training, the guidelines particularly recommend standardized drug therapy. In the present article we summarize the recommended pharmacotherapy for patients with bronchial asthma.

Pharmacogenetics of asthma

PURPOSE OF REVIEW

Patient response to the asthma drug classes, bronchodilators, inhaled corticosteroids and leukotriene modifiers, are characterized by a large degree of heterogeneity, which is attributable in part to genetic variation. Herein, we review and update the pharmacogenetics and pharmaogenomics of common asthma drugs.

RECENT FINDINGS

Early studies suggest that bronchodilator reversibility and asthma worsening in patients on continuous short-acting and long-acting beta-agonists are related to the Gly16Arg genotype for the ADRB2. More recent studies including genome-wide association studies implicate variants in other genes contribute to bronchodilator response heterogeneity and fail to replicate asthma worsening associated with continuous beta-agonist use. Genetic determinants of the safety of long-acting beta-agonist require further study. Variants in CRHR1, TBX21, and FCER2 contribute to variability in response for lung function, airways responsiveness, and exacerbations in patients taking inhaled corticosteroids. Variants in ALOX5, LTA4H, LTC4S, ABCC1, CYSLTR2, and SLCO2B1 contribute to variability in response to leukotriene modifiers.

SUMMARY

Identification of novel variants that contribute to response heterogeneity supports future studies of single nucleotide polymorphism discovery and include gene expression and genome-wide association studies. Statistical models that predict the genomics of response to asthma drugs will complement single nucleotide polymorphism discovery in moving toward personalized medicine.

The impact of GINA suggested drugs for the treatment of asthma on Health-Related Quality of Life: a GA(2)LEN review

Asthma represents a serious global health problem. People of all ages in countries throughout the world are affected by this chronic airway disorder that, when uncontrolled, can place severe limits on daily life and can even be fatal. Asthma cannot be removed, but asthmatic symptoms can be cured; as for many other chronic diseases, pharmacotherapy is important to reduce the risk of asthma-related mortality, decrease disability and improve symptoms and quality of life. The action of antiasthmatic drugs directly contributes to decrease symptoms severity, improve spirometric results, reduce airway hyperresponsiveness and prevent irreversible airway remodelling. Antiasthmatic therapy is necessary for long-term control of asthma symptoms. Asthma and antiasthmatic drugs can influence patient's quality of life: this is why healthcare systems have recently focused on research studies about Health-Related Quality of Life (HRQL) in asthmatic patients. Numerous validated questionnaires are available and many studies have been performed evaluating HRQL in people affected by asthma, thus testifying a great interest in this topic. The aims of the present review are to examine the scientific literature of the last 4 years (January 2004-December 2007) dealing with the impact of asthma treatments suggested by Global Initiative for Asthma guidelines on patients' quality of life, and to identify the unexplored or not fully investigated areas concerning this issue.

ARG1 is a novel bronchodilator response gene: screening and replication in four asthma cohorts

RATIONALE

Inhaled beta-agonists are one of the most widely used classes of drugs for the treatment of asthma. However, a substantial proportion of patients with asthma do not have a favorable response to these drugs, and identifying genetic determinants of drug response may aid in tailoring treatment for individual patients.

OBJECTIVES

To screen variants in candidate genes in the steroid and beta-adrenergic pathways for association with response to inhaled beta-agonists.

METHODS

We genotyped 844 single nucleotide polymorphisms (SNPs) in 111 candidate genes in 209 children and their parents participating in the Childhood Asthma Management Program. We screened the association of these SNPs with acute response to inhaled beta-agonists (bronchodilator response [BDR]) using a novel algorithm implemented in a family-based association test that ranked SNPs in order of statistical power. Genes that had SNPs with median power in the highest quartile were then taken for replication analyses in three other asthma cohorts.

MEASUREMENTS AND MAIN RESULTS

We identified 17 genes from the screening algorithm and genotyped 99 SNPs from these genes in a second population of patients with asthma. We then genotyped 63 SNPs from four genes with significant associations with BDR, for replication in a third and fourth population of patients with asthma. Evidence for association from the four asthma cohorts was combined, and SNPs from ARG1 were significantly associated with BDR. SNP rs2781659 survived Bonferroni correction for multiple testing (combined P value = 0.00048, adjusted P value = 0.047).

CONCLUSIONS

These findings identify ARG1 as a novel gene for acute BDR in both children and adults with asthma.

Sleep quality in asthma: results of a large prospective clinical trial

RATIONALE

Previous studies have suggested that asthmatics have an increased incidence of sleep disturbances. However, these studies have been limited by reliance on population surveys or small numbers of participants.

OBJECTIVES

We sought to measure sleep quality and daytime sleepiness in a cohort of symptomatic asthmatics and to measure the effects of improved asthma control on sleep quality.

METHODS

Data were collected in sub-study of a large multi-center randomized double-masked controlled trial of mild-moderate asthmatics evaluating the effect of low-dose theophylline on asthma control in comparison to montelukast and placebo. Each participant was administered sleep symptom questionnaires at randomization and at the final visit (6 months after randomization). These included the Pittsburgh Sleep Quality Questionnaire (PSQI) and the Epworth Sleepiness Scale (ESS).

MEASUREMENTS AND MAIN RESULTS

Data were available for 487 participants. Baseline mean values were: age 40 +/- 15 years, 74% female, forced expiratory volume in 1 second (FEV(1)) 79 +16 percent predicted, Juniper Asthma Control Questionnaire (ACQ) score 2.35 +/- 0.63, PSQI 7.8 +/-4, and ESS 8.5 +/-4.9. There were no significant differences in the PSQI or ESS between the three treatment groups. Significant correlations were found at baseline between the global PSQI score and ACQ and quality of life and marginally with lung function. Significant correlation existed between improvements in PSQI and ESS with improved asthma control and quality of life.

CONCLUSIONS

Sleep disturbances are common in asthmatics and are associated with asthma control and quality of life. Clinicians caring for asthmatics may need to complete a more detailed sleep history in patients with poorly controlled asthma. In addition, low-dose theophylline does not seem to impair sleep quality in asthmatics.

Targeting airway inflammation in asthma: current and future therapies

Asthma is a chronic inflammatory disease of the airway that requires long-term antiinflammatory therapy. Inhaled corticosteroids (ICSs) are recommended for first-line treatment of persistent disease, but not all patients achieve asthma control even when these agents are used in high doses and in combination with other medications, including a long-acting beta(2)-agonist or a leukotriene modifier. Such patients may require additional therapy. As information about asthma pathophysiology and inflammatory phenotypes continues to increase, and additional antiinflammatory options become available, it may be possible to target antiinflammatory therapy to various aspects of the disease and consequently to improve the treatment of patients with inadequate responses to standard ICS-based therapy. Several novel antiinflammatory therapies are in different stages of clinical development. The most clinically advanced of these is omalizumab, a recombinant humanized monoclonal antibody that specifically targets IgE and is indicated for patients with moderate-to-severe asthma caused by allergies. Omalizumab has demonstrated efficacy in patients with moderate-to-severe asthma and documented evidence of allergen sensitivity. Other key therapy options in clinical development either target proinflammatory cytokines (eg, interleukin-4 and tumor necrosis factor-alpha) or inflammatory cells (eg, T-helper type 2 cells and eosinophils). This review provides an overview of the current and future approaches targeting airway inflammation in patients with asthma.

Association of corticotropin-releasing hormone receptor-2 genetic variants with acute bronchodilator response in asthma

OBJECTIVE

Corticotropin-releasing hormone receptor (CRHR)-2 participates in smooth muscle relaxation response and may influence acute airway bronchodilator response to short-acting beta2-agonist treatment of asthma. We aim to assess associations between genetic variants of CRHR2 and acute bronchodilator response in asthma.

METHODS

We investigated 28 single nucleotide polymorphisms in CRHR2 for associations with acute bronchodilator response to albuterol in 607 Caucasian asthmatic patients recruited as part of the Childhood Asthma Management Program. Replication was conducted in two Caucasian adult asthma cohorts--a cohort of 427 participants enrolled in a completed clinical trial conducted by Sepracor Inc. (Massachusetts, USA) and a cohort of 152 participants enrolled in the Clinical Trial of Low-Dose Theophylline and Montelukast conducted by the American Lung Association Asthma Clinical Research Centers.

RESULTS

Five variants were significantly associated with acute bronchodilator response in at least one cohort (P

CONCLUSION

We report for the first time, at the gene level, replicated associations between CRHR2 and acute bronchodilator response. Although no single variant was significantly associated in all three cohorts, the findings that variants at the 5' end of CRHR2 are associated in each of three cohorts strongly suggest that the causative variants reside in this region and its genetic effect, although present, is likely to be weak.

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Key Words

• asthma
• genetics
• corticotrophin releasing hormone receptor 2
• crhr2
• bronchodilator response
• polymorphism
• β₂ adrenergic receptor agonist

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MESH Headings

• Albuterol/therapeutic use
• Anti-Asthmatic Agents/adverse effects
• Anti-Asthmatic Agents/therapeutic use
• Asthma/drug therapy
• Asthma/genetics
• Asthma/physiopathology
• Bronchodilator Agents/therapeutic use
• Child
• Child, Preschool
• Double-Blind Method
• Female
• Gene Frequency
• Humans
• Linkage Disequilibrium
• Male
• Placebos
• Polymorphism, Single Nucleotide
• Receptors, Corticotropin-Releasing Hormone/genetics
• Respiration/drug effects
• Respiration/genetics
• Theophylline/therapeutic use
• Time Factors
• Treatment Outcome

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Grants

• U01 HL065899 NHLBI NIH HHS
• UO1 HL65899 NHLBI NIH HHS
• P01 HL067664 NHLBI NIH HHS
• N01HR16049 NHLBI NIH HHS
• N01-HR-16049 NHLBI NIH HHS
• R01 HL071394 NHLBI NIH HHS
• HL-071394 NHLBI NIH HHS
• P01 HL67664 NHLBI NIH HHS

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Affiliation(s)

Audrey H Poon Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
Kelan G Tantisira
Augusto A Litonjua
Ross Lazarus
Jingsong Xu
Jessica Lasky-Su
John J Lima
Charles G Irvin
John P Hanrahan
Christoph Lange
Scott T Weiss

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Targeting improvements in asthma morbidity in Chicago: a 10-year retrospective of community action

Chicago has been described as "asthma ground zero" due to its disproportionately high rates of asthma-related hospitalization and mortality. Asthma prevalence rates in Chicago are higher for whites and African Americans than the national average. In an effort to address the asthma burden and disparities in Chicago, multiple initiatives throughout the city have been launched and continue due largely to the support of the Otho S.A. Sprague Memorial Institute. The purpose of this article is to describe the policy, advocacy, educational, surveillance, research, quality improvement, community, and consortia activities over the past 10 years and their impact on asthma morbidity and disparities in Chicago.

Recent development in pharmacogenomics: from candidate genes to genome-wide association studies

Genetic diversity, most notably through single nucleotide polymorphisms and copy-number variation, together with specific environmental exposures, contributes to both disease susceptibility and drug response variability. It has proved difficult to isolate disease genes that confer susceptibility to complex disorders, and as a consequence, even fewer genetic variants that influence clinical drug responsiveness have been uncovered. As such, the candidate gene approach has largely failed to deliver and, although the family-based linkage approach has certain theoretical advantages in dealing with common/complex disorders, progress has been slower than was hoped. More recently, genome-wide association studies have gained increasing popularity, as they enable scientists to robustly associate specific variants with the predisposition for complex disease, such as age-related macular degeneration, Type 2 diabetes, inflammatory bowel disease, obesity, autism and leukemia. This relatively new methodology has stirred new hope for the mapping of genes that regulate drug response related to these conditions. Collectively, these studies support the notion that modern high-throughput single nucleotide polymorphism genotyping technologies, when applied to large and comprehensively phenotyped patient cohorts, will readily reveal the most clinically relevant disease-modifying and drug response genes. This review addresses both recent advances in the genotyping field and highlights from genome-wide association studies, which have conclusively uncovered variants that underlie disease susceptibility and/or variability in drug response in common disorders.

Placebo versus best-available-therapy control group in clinical trials for pharmacologic therapies: which is better?

There are valid scientific and ethical considerations for using a control group in a clinical trial. Placebo-controlled trials are justifiable when they are supported by sound methodologic consideration and when their use does not expose research participants to excessive risk of harm. Consideration should be given to "best available therapy" control groups in the evaluation of a new therapy or intervention over an existing therapy. Investigators should keep in mind that one should not sacrifice the scientific merit of a trial to include a best-available-therapy control group as long as the placebo control group poses little harm to participants and, importantly, the trial offers potential benefit to the subject. The pros and cons of using placebo versus best-available-therapy control groups are discussed.

The effect of montelukast and low-dose theophylline on cardiovascular disease risk factors in asthmatics

BACKGROUND

Recent studies have implicated the 5-lipoxygenase/leukotriene (LT) pathway in cardiovascular disease (CVD), which may have important implications for asthmatics because several drugs that target this pathway are currently used to treat asthma. We sought to determine whether montelukast, a cysteinyl LT antagonist, and low-dose theophylline affected serum inflammatory and lipid CVD risk factors in a recently completed clinical trial in asthmatic patients.

METHODS

Patients were randomized to receive either montelukast (10 mg/d), theophylline (300 mg/d), or placebo. A baseline run-in period of 7 to 14 days was followed by treatment for 6 months. Serum levels of C-reactive protein (CRP), interleukin-6, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density cholesterol (HDL-C) were measured 1 month and 6 months after treatment.

RESULTS

Patients with moderate-to-severe asthma receiving montelukast (n = 60) had significantly lower serum CRP compared to placebo (n = 73) after 1 month (1.7 mg/L vs 3.2 mg/L, respectively; p < 0.006) and 6 months of treatment (2.3 mg/L vs 3.5 mg/L, respectively; p < 0.04). At both time points, serum levels of all lipids were also significantly lower in the montelukast and theophylline groups compared to placebo, but these effects were primarily observed in individuals who were also receiving inhaled corticosteroids as monotherapy for asthma.

CONCLUSIONS

Asthmatic patients receiving montelukast and, to some extent, low-dose theophylline have lower levels of CVD-associated inflammatory biomarkers and lipid levels. These observations suggest these asthma medications may have some beneficial value in asthmatics with respect to CVD risk, although the effects on HDL-C levels should also be taken into consideration.

Treatment heterogeneity in asthma: genetics of response to leukotriene modifiers

Despite advances in treatment, asthma continues to be a significant health and economic burden. Although asthma cannot be cured, several drugs, including beta2 agonists, corticosteroids, and leukotriene (LT) modifiers, are well tolerated and effective in minimizing symptoms, improving lung function, and preventing exacerbations. However, inter-patient variability in response to asthma drugs limits their effectiveness. It has been estimated that 60-80% of this inter-patient variability may be attributable to genetic variation. LT modifiers, in particular, have been associated with heterogeneity in response. These drugs exert their action by inhibiting the activity of cysteinyl leukotrienes (CysLTs), which are potent bronchoconstrictors and pro-inflammatory agents. Two classes of LT modifiers are 5-lipoxygenase (ALOX5) inhibitors (zileuton) and leukotriene receptor antagonists (LTRAs) [montelukast, pranlukast, and zarfirlukast]. LT modifiers can be used as alternatives to low-dose inhaled corticosteroids (ICS) in mild persistent asthma, as add-on therapy to low- to medium-dose ICS in moderate persistent asthma, and as add-on to high-dose ICS and a long-acting ss2 agonist in severe persistent asthma. At least six genes encode key proteins in the LT pathway: arachidonate 5-lipoxygenase (ALOX5), ALOX5 activating protein (ALOX5AP [FLAP]), leukotriene A4 hydrolase (LTA4H), LTC4 synthase (LTC4S), the ATP-binding cassette family member ABCC1 (multidrug resistance protein 1 [MRP1]), and cysteinyl leukotriene receptor 1 (CYSLTR1). Studies have reported that genetic variation in ALOX5, LTA4H, LTC4S, and ABCC1 influences response to LT modifiers. Plasma concentrations of LTRAs vary considerably among patients. Physio-chemical characteristics make it likely that membrane efflux and uptake transporters mediate the absorption of LTRAs into the systemic circulation following oral administration. Genes that encode efflux and uptake transport proteins harbor many variants that could influence the pharmacokinetics, and particularly the bioavailability, of LTRAs, and could contribute to heterogeneity in response. In the future, large, well designed clinical trials studying the pharmacogenetics of LT modifiers in diverse populations are warranted to determine whether a genetic signature can be developed that will accurately predict which patients will respond.

Oral xanthines as maintenance treatment for asthma in children

BACKGROUND

Xanthines have been used in the treatment of asthma as a bronchodilator, though they may also have anti-inflammatory effects. The current role of xanthines in the long-term treatment of childhood asthma needs to be reassessed.

OBJECTIVES

To determine the efficacy of xanthines (e.g. theophylline) in the maintenance treatment of paediatric asthma.

SEARCH STRATEGY

A search of the Cochrane Airways Group Specialised Register was undertaken with predefined search terms. Searches are current to May 2005.

SELECTION CRITERIA

Randomised controlled trials,lasting at least four weeks comparing a xanthine with placebo, regular short-acting beta-agonist (SABA), inhaled corticosteroids (ICS), cromoglycate (SCG), ketotifen (KET) or leukotriene antagonist, in children with diagnosed with chronic asthma between 18 months and 18 years old.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected each study for inclusion in the review and extracted data. Primary outcome was percentage of symptom-free days.

MAIN RESULTS

Thirty-four studies (2734 participants) of adequate quality were included. Xanthine versus placebo (17 studies): The proportion of symptom free days was larger with xanthine compared with placebo (7.97% [95% CI 3.41, 12.53]). Rescue medication usage was lower with xanthine, with no significant difference in symptom scores or hospitalisations. FEV1 , and PEF were better with xanthine. Xanthine was associated with non - specific side-effects. Data from behavioural scores were inconclusive. Xanthine versus ICS (four studies) : Exacerbations were less frequent with ICS, but no significant difference on lung function was observed. Individual studies reported significant improvements in symptom measures in favour of steroids, and one study reported a difference in growth rate in favour of xanthine. No difference was observed for study withdrawal or tremor. Xanthine was associated with more frequent headache and nausea. Xanthine versus regular SABA (10 studies): No significant difference in symptoms, rescue medication usage and spirometry. Individual studies reported improvement in PEF with beta-agonist. Beta-agonist treatment led to fewer hospitalisations and headaches. Xanthine was associated with less tremor. Xanthine versus SCG (six studies ): No significant difference in symptoms, exacerbations and rescue medication. Sodium cromoglycate was associated with fewer gastro-intestinal side-effects than xanthine. Xanthine versus KET (one study): No statistical tests of significance between xanthine and ketotifen were reported. Xanthine + ICS versus placebo + same dose ICS (three studies) : Results were conflicting due to clinical/methodological differences, and could not be aggregated.

AUTHORS' CONCLUSIONS

Xanthines as first-line preventer alleviate symptoms and reduce requirement for rescue medication in children with mild to moderate asthma. When compared with ICS they were less effective in preventing exacerbations. Xanthines had similar efficacy as single preventative agent compared with regular SABA and SCG. Evidence on AEs (adverse effects) was equivocal: there was evidence for increased AEs overall, but no evidence that any specific AE (including effects on behaviour and attention) occurred more frequently than with placebo. There is insufficient evidence from available studies to make firm conclusions about the effectiveness of xanthines as add-on preventative treatment to ICS, and there are no published paediatric studies comparing xanthines with alternatives in this role. Our data suggest that xanthines are only suitable as first-line preventative asthma therapy in children when ICS are not available. They may have a role as add-on therapy in more severe asthma not controlled by ICS, but further studies are needed to examine this, and to define the risk-benefit ratio compared with other agents.