Long-acting beta2-agonists: comparative pharmacology and clinical outcomes

Onset of bronchodilation with fluticasone/formoterol combination versus fluticasone/salmeterol in an open-label, randomized study

INTRODUCTION

The inhaled corticosteroid, fluticasone propionate (fluticasone), and the long-acting beta(2)-agonist, formoterol fumarate (formoterol), have been combined in a single aerosol inhaler (fluticasone/formoterol). In a randomized, open-label study, fluticasone/formoterol showed similar efficacy to fluticasone/salmeterol after 12 weeks of treatment. This post-hoc analysis compared the onset of bronchodilation with the two treatments.

METHODS

Adults with mild-to-moderate-severe persistent asthma were randomized to fluticasone/formoterol (100/10 or 250/10 μg twice daily [b.i.d.]) or fluticasone/salmeterol (100/50 or 250/50 μg b.i.d.) for 12 weeks. The onset of bronchodilation (the first post-dose time point at which the forced expiratory volume in 1 second [FEV(1)] was ≥12% greater than the pre-dose value), responder rates (the proportion of patients achieving bronchodilation), and changes in FEV(1) were assessed at days 0 (baseline) and 84.

RESULTS

Fluticasone/formoterol (n = 101) provided more rapid onset of bronchodilation than fluticasone/salmeterol (n = 101) over the first 120 min post-dose on days 0 (hazard ratio [HR] = 1.47 [95% CI 1.05-2.05]) and 84 (HR = 1.77 [95% CI 1.14-2.73]). The odds of a patient achieving bronchodilation within 5 min of dosing were almost four-times higher with fluticasone/formoterol than with fluticasone/salmeterol on day 0 (odds ratio [OR] = 3.97 [95% CI 1.96-8.03]) and almost 10-times higher on day 84 (OR = 9.58 [95% CI 2.14-42.90]); the odds of achieving bronchodilation within 120 min post-dose were approximately twofold higher with fluticasone/formoterol on both days. The overall percentage increase in least-squares (LS) mean FEV1 during the 120-min post-dose period was significantly greater with fluticasone/formoterol than fluticasone/salmeterol on days 0 (LS mean treatment difference: 4.70% [95% CI 1.57-7.83]; P = 0.003) and 84 (2.79% [95% CI 0.65-4.93]; P = 0.011).

CONCLUSION

These analyses showed that fluticasone/formoterol provided a faster onset of bronchodilation than fluticasone/salmeterol, which was maintained over 12 weeks of treatment. This benefit may facilitate treatment adherence among patients with asthma.

Budesonide/formoterol combination in COPD: a US perspective

Chronic obstructive pulmonary disease (COPD) is a preventable and treatable disease of the lung caused primarily by exposure to cigarette smoke. Clinically, it presents with progressive cough, sputum production, dyspnea, reduced exercise capacity, and diminished quality of life. Physiologically, it is characterized by the presence of partially reversible expiratory airflow limitation and hyperinflation. Pathologically, COPD is a multicomponent disease characterized by bronchial submucosal mucous gland hypertrophy, bronchiolar mucosal hyperplasia, increased luminal inflammatory mucus, airway wall inflammation and scarring, and alveolar wall damage and destruction. Management of COPD involves both pharmacological and nonpharmacological approaches. Bronchodilators and inhaled corticosteroids are recommended medications for management of COPD especially in more severe disease. Combination therapies containing these medications are now available for the chronic management of stable COPD. The US Food and Drug Administration, recently, approved the combination of budesonide/formoterol (160/4.5 μg; Symbicort™, AstraZeneca, Sweden) delivered via a pressurized meter dose inhaler for maintenance management of stable COPD. The combination also is delivered via dry powder inhaler (Symbicort™ and Turbuhaler™, AstraZeneca, Sweden) but is not approved for use in the United States. In this review, we evaluate available data of the efficacy and safety of this combination in patients with COPD.

Effects of asthma treatment: the present and future

The increasing burden of asthma in both primary and secondary care has led to extensive research into its genetics, pathophysiology and treatment over the past few decades. Inhaled corticosteroids remain an integral component in all but the mildest disease, although despite a low-to-moderate dose, many individuals remain symptomatic. In patients with persistent symptoms despite inhaled corticosteroids, a variety of different nonsteroidal second-line therapies are available as add-on therapy. In this review, existing and potential future pharmacological strategies involved in the management of asthma will be highlighted.

The preclinical toxicology of salmeterol hydroxynaphthoate

An extensive toxicology programme on salmeterol hydroxynaphthoate (SereventTM), a marketed long-acting β2-adrenoceptor agonist, has been carried out. The studies evaluated both the local (respiratory tract) and systemic tolerance to single and repeated dosing, effects on all stages of reproduction, as well as the genotoxic and oncogenic potential. High acute doses were well tolerated and caused no specific target organ toxicity. In repeat dose studies, animals tolerated salmeterol very well both locally and systemically. No significant effects on the respiratory tract of dogs were seen and only minor laryngeal changes, typical of those occurring with many inhaled medicines, were noted in rats. The high systemic concentrations achieved resulted in a number of changes that are considered to be the result of excessive and prolonged β 2-adrenoceptor stimulation. These included tachycardia, skeletal muscle hypertrophy and minor haematological and blood biochemical changes in general toxicity studies, foetal effects in rabbit organogenesis studies and increased incidences of smooth muscle tumours of the mesovarium in the rat and of the uterus in the mouse oncogenicity studies. Salmeterol showed no evidence of any genotoxic potential. Results of the extensive toxicology programme provide good assurance of the safety for the inhaled use of salmeterol in patients; this has ben confirmed by many years of clinical experience during its development and marketing.

Formoterol dry-powder inhaler for the treatment of asthma and chronic obstructive pulmonary disease

Formoterol, a long-acting beta2-adrenergic agonist, is used as an inhaled bronchodilator therapy for patients with asthma or for the prevention of exercise-induced bronchospasm in children and in chronic obstructive pulmonary disease. Formoterol has unique characteristics of rapid onset and sustained duration of action compared with other bronchodilators. In addition to its effectiveness as regular maintenance therapy in asthma and chronic obstructive pulmonary disease, formoterol is also reported to be effective as an as-needed reliever therapy in patients with asthma. Formoterol is available in several different types of dry-powder inhalers and pressurized metered-dose inhalers.

Asthmatic patients' poor awareness of inadequate disease control: a pharmacy-based survey

BACKGROUND

Many asthmatic patients fail to perceive their level of disease control.

OBJECTIVE

To investigate whether patients' ability to identify asthma control varied with personal characteristics or factors related to disease management.

METHODS

Asthmatic patients were consecutively recruited at 348 pharmacies. They completed a questionnaire (regarding personal characteristics and asthma management) linked to pharmacies records of dispensed medications. The Asthma Control Test questionnaire includes 4 dimensions of asthma control (activity limitations, dyspnea, nocturnal awakenings, and rescue medication use) and assesses patients' perception of control ("How would you rate your asthma control during the past 14 days?"). Analyses were restricted to patients with inadequate control. Patients' perception of control was compared across the other dimensions of the questionnaire. The correlates of patients' failure to perceive inadequate asthma control were investigated.

RESULTS

Seven hundred eighteen (68.5%) of the 1,048 patients with inadequate asthma control and documented perception of control considered themselves to be "completely" or "well" controlled. Patients' perception of control did not vary with each dimension of inadequate control. High rates of failure to perceive poor control were observed in patients with at least weekly dyspneas (60%) or nocturnal symptoms (60%). Failure to perceive inadequate control was more likely in patients aged 41 to 50 years (odds ratio, 1.51; 95% confidence interval, 1.05-2.15). No significant effect of factors related to asthma management was observed.

CONCLUSIONS

Patients with most uncontrolled asthma have difficulty in properly perceiving their level of disease control regardless of their personal characteristics or disease management. The reasons for this poor perception should be investigated. Education programs should be created that focus on knowledge of asthma miscontrol criteria.

Bioluminescence resonance energy transfer as a screening assay: Focus on partial and inverse agonism

The reported data for compound screening with the bioluminescence resonance energy transfer (BRET2) assay is very limited, and several questions remain unaddressed, such as the behavior of agonists. Eleven beta2 adrenergic receptor (beta2-AR) agonists were tested for full or partial agonism in an improved version of the receptor/beta-arrestin2 BRET2 assay and in 2 cyclic adenosine monophosphate (cAMP) assays (column cAMP assay and ALPHAscreen cAMP assay). Tested in the highly sensitive ALPHAscreen cAMP assay, all selected agonists behaved as full agonists, using isoproterenol as a reference compound. In the less sensitive column cAMP assay, ephedrine and dopamine had a clear partial response. For the BRET2 assay, a highly graded picture was obtained. Moreover, beta2-AR antagonists were tested for inverse agonism. Pronounced inverse agonism was detected in the ALPHAscreen cAMP assay. Only marginal inverse agonistic responses were seen for alprenolol and pindolol in the column cAMP assay, and no inverse agonism was seen in the BRET2 assay. For the beta2-AR, the BRET2 assay may be superior for secondary screening of agonists where a separation of full and partial agonists is needed and the ALPHAscreen cAMP assay may be preferred for primary screening of agonists where all receptor activating compounds are desired.

Effects of tiotropium and other long acting bronchodilators in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) accounts for a major workload in both primary and secondary care. It is characterised by progressive airflow obstruction which does not fully reverse to inhaled or oral pharmacotherapy. The diagnosis should be considered in any current or former smoker who has symptoms of breathlessness, wheeze, cough, sputum production and impaired exercise tolerance. From a pharmacological perspective, short-acting bronchodilators (anti-cholinergics and beta(2)-agonists) play a vital role in immediate relief of symptoms. However, in patients with persistent symptoms and exacerbations, long-acting bronchodilator therapy is advocated for regular use. Tiotropium is a newly introduced long-acting anti-cholinergic which facilitates once daily administration. This evidence based review article discusses the use of long acting bronchodilators in COPD with a particular emphasis on the putative benefits of tiotropium.

N-coumaroyldopamine and N-caffeoyldopamine increase cAMP via beta 2-adrenoceptors in myelocytic U937 cells

N-caffeoyldopamine is a phytochemical found in various plants, including cocoa (Theobroma cacao L.). N-caffeoyldopamine and its natural analogs (N-cinnamoyldopamine, N-coumaroyldopamine, N-feruloyldopamine, and N-sinapoyldopamine) were synthesized and investigated to determine their potency as beta-adrenoceptor agonists, because they have chemical structural moieties found in beta-adrenoceptor agonists. Among the compounds tested in this study, N-coumaroyldopamine and N-caffeoyldopamine were the two most potent compounds, able to increase cAMP at the concentrations < 0.05 microM in U937 cells. The decreasing order of potency was N-coumaroyldopamine > N-caffeoyldopamine > N-feruloyldopamine > N-sinapoyldopamine > N-cinnamoyldopamine. Using beta2-specific antagonists (butoxamine and ICI 118551), N-coumaroyldopamine and N-caffeoyldopamine were found to increase cAMP via beta2-adrenoceptors in U937 cells. In producing cAMP in U937 cells, N-coumaroyldopamine and N-caffeoyldopamine were as potent as several well-known beta2-adrenoceptor agonists (salbutamol, procaterol, and fenoterol). These results indicate that N-coumaroyldopamine and N-caffeoyldopamine are potent compounds able to increase cAMP via beta2-adrenoceptors in U937 cells, and may have potential effects on human health.

Effects of dual therapy with corticosteroids plus long acting beta2-agonists in asthma

Asthma is a common condition characterised by inflammation, airway hyperresponsiveness and reversible airflow obstruction. Effective pharmacotherapy must therefore be aimed at attenuating these underlying hallmark features. Despite the use of regular low-to-moderate doses of inhaled corticosteroids, many patients remain symptomatic and require further 2nd line controller therapy. The addition of a concomitant long acting beta2-agonist provides an effective means in which to alleviate symptoms and reduce exacerbation frequency. Moreover, both agents can be combined in a single inhaler, and provide patients with a more convenient and effective way in which to deliver treatment to the endobronchial tree. This evidenced-based review article discusses the effects of such combination inhalers upon a variety of outcome parameters and their effects upon asthmatics across a range of severities.