Second-line controller therapy for persistent asthma uncontrolled on inhaled corticosteroids: the step 3 dilemma

Cysteinyl leukotriene receptor-1 antagonists as modulators of innate immune cell function

Cysteinyl leukotrienes (cysLTs) are produced predominantly by cells of the innate immune system, especially basophils, eosinophils, mast cells, and monocytes/macrophages. Notwithstanding potent bronchoconstrictor activity, cysLTs are also proinflammatory consequent to their autocrine and paracrine interactions with G-protein-coupled receptors expressed not only on the aforementioned cell types, but also on Th2 lymphocytes, as well as structural cells, and to a lesser extent neutrophils and CD8⁺ cells. Recognition of the involvement of cysLTs in the immunopathogenesis of various types of acute and chronic inflammatory disorders, especially bronchial asthma, prompted the development of selective cysLT receptor-1 (cysLTR1) antagonists, specifically montelukast, pranlukast, and zafirlukast. More recently these agents have also been reported to possess secondary anti-inflammatory activities, distinct from cysLTR1 antagonism, which appear to be particularly effective in targeting neutrophils and monocytes/macrophages. Underlying mechanisms include interference with cyclic nucleotide phosphodiesterases, 5′-lipoxygenase, and the proinflammatory transcription factor, nuclear factor kappa B. These and other secondary anti-inflammatory mechanisms of the commonly used cysLTR1 antagonists are the major focus of the current review, which also includes a comparison of the anti-inflammatory effects of montelukast, pranlukast, and zafirlukast on human neutrophils in vitro, as well as an overview of both the current clinical applications of these agents and potential future applications based on preclinical and early clinical studies.

Clinico-immunological changes post-immunotherapy with Periplaneta americana

BACKGROUND

Cockroach proteins induce allergies including asthma in predisposed individuals. Well-designed controlled studies are required to show the effect of cockroach immunotherapy (IT). This study is aimed to assess changes in clinical and immunological parameters post-IT with Periplaneta americana extract.

MATERIALS AND METHODS

A double-blind, placebo-controlled trial of cockroach IT was performed for 1year in 50 patients of asthma, rhinitis or both. The efficacy of IT was assessed by change in skin reactivity and clinical parameters such as symptom/drug score, airway reactivity and immunological parameters namely IgE, IgG1 and IgG4, IL-4 and IFN-γ by enzyme-linked immunosorbent assay and western blotting using patients' sera at baseline and after 1year of treatment.

RESULTS

Immunotherapy with cockroach extract demonstrated significant improvement in clinical parameters of active group patients compared with baseline values and placebo group. Specific IgE levels showed a modest reduction, while IgG4 levels increased significantly in active IT group after 1year. IgE immunoblotting demonstrated reduction in intensity and number of specific bands, whereas IgG4 binding showed more number and distinct bands following IT. Active group patients showed correlation between increase in IgG4/IgG1 ratio and reduction in symptom score post-IT.

CONCLUSIONS

Immunotherapy with cockroach extract improved clinical and immunological status of asthma and rhinitis patients. Clinical improvement in patients after IT is associated with immunological changes.

Efficacy of add-on montelukast in patients with non-controlled asthma: a Belgian open-label study

OBJECTIVE

To evaluate the efficacy of add-on montelukast on asthma control and allergic rhinitis symptoms in asthmatic patients still symptomatic with chronic treatment with inhaled corticosteroid and long-acting beta(2) agonist (ICS/LABA), irrespective of the dose.

RESEARCH DESIGN AND METHODS

This 2-month, open-label, real-life, multicentre, observational study was undertaken by 499 general practitioners in Belgium. Patients (>or= 4 years old) with uncontrolled asthma despite fluticasone/salmeterol or budesonide/formoterol therapy had oral montelukast 4, 5, or 10 mg daily added to their therapy, depending on the registered dose for their age. Asthma control, assessed by the 6-item Juniper Asthma Control Questionnaire (ACQ) was recorded at baseline and after 2 months of treatment with montelukast and the patients' global evaluation of asthma was also recorded at the end of the study. Concomitant allergic rhinitis symptoms were evaluated according to the patients' perception.

RESULTS

A total of 5769 patients were eligible for analysis. Addition of montelukast was associated with significant decrease in mean (SD) ACQ score (from 1.97 [0.77] at baseline to 1.05 [0.69] after add-on treatment, p < 0.001). There was also a significant improvement in all individual symptoms of the ACQ score (p < 0.001). After 2 months, 89% of the patients reported global improvement of their asthma, with a good correlation between patients' global evaluation and change in ACQ scores. Of the 2442 patients who reported allergic rhinitis symptoms at baseline, 91% showed a global improvement of their asthma symptoms and 82% in their rhinitis symptoms after adding montelukast.

CONCLUSION

This open-label observational study showed an improvement, after 2 months of add-on therapy with montelukast, in both asthma and allergic rhinitis symptoms in patients not adequately controlled on a fixed association of ICS/LABA.

Immunotherapy with mosquito (Culex quinquefasciatus) extract: a double-blind, placebo-controlled study

BACKGROUND

Mosquito allergy is well established, but mosquito immunotherapy requires validation using clinical and immunologic variables.

OBJECTIVE

To evaluate the tolerability and efficacy of specific immunotherapy with Culex quinquefasciatus (mosquito) extract.

METHODS

We performed a randomized, double-blind, placebo-controlled trial of immunotherapy for 1 year in 40 patients with asthma, rhinitis, or both. Patients were evaluated by means of intradermal testing, symptom and drug scores, and histamine provocation testing before and after 1 year of immunotherapy. Mosquito specific IgE and IgG subclass antibody responses were evaluated at the basal level and after 1 year.

RESULTS

Patients receiving allergen immunotherapy for 1 year showed a significant improvement compared with baseline and patients receiving placebo regarding skin reactions, symptom scores (rhinitis and asthma), and forced expiratory volume in 1 second. Provocation concentration of histamine that caused a decrease in forced expiratory volume in 1 second of 20% by inhalation was elevated in the group receiving immunotherapy. In the active group serologic analysis showed a slight reduction in IgE levels (P = .02) but a significant elevation in IgG4 levels (P = .001), with a significant decrease in the IgE/IgG4 ratio (P = .001). All these changes in the placebo group were nonsignificant.

CONCLUSIONS

Allergen immunotherapy with mosquito extract was well tolerated, with improvement in symptoms and airway reactivity. Good clinical outcome was associated with increased IgG4 antibody levels.

Recent advances in the development of anti-allergic drugs

Research over the past decade has provided information concerning the onset and treatment of allergic diseases, including bronchial asthma, allergic rhinitis and atopic dermatitis. Recent studies also indicated that allergic inflammation is the basic pathophysiology of allergic diseases and is closely associated with their progression and exacerbation. Our understanding of the mechanism of allergic inflammation with regard to therapeutic agents has improved as a result of immunological and molecular biological studies. While much effort has been paid to developing a new anti-allergic drug, allergic disease has yet to be completely conquered. More extensive research will allow the development of new therapeutics to combat allergic diseases. This article provides an overview of recent advances in the development of anti-allergic drugs.

Add-on therapy options in asthma not adequately controlled by inhaled corticosteroids: a comprehensive review

Many patients with persistent asthma can be controlled with inhaled corticosteroids (ICS). However, a considerable proportion of patients remain symptomatic, despite the use of ICS. We present systematically evidence that supports the different treatment options. A literature search was made of Medline/PubMed to identify randomised and blinded trials. To demonstrate the benefit that can be obtained by increasing the dose of ICS, dose-response studies with at least three different ICS doses were identified. To demonstrate whether more benefit can be obtained by adding long-acting beta2-agonist (LABA), leukotriene antagonist (LTRA) or theophylline than by increasing the dose of ICS, studies comparing these options were identified. Thirdly, studies comparing the different "add-on" options were identified. The addition of a LABA is more effective than increasing the dose of ICS in improving asthma control. By increasing the dose of ICS, clinical improvement is likely to be of small magnitude. Addition of a LTRA or theophylline to the treatment regimen appears to be equivalent to doubling the dose of ICS. Addition of a LABA seems to be superior to an LTRA in improving lung function. However, addition of LABA and LTRA may be equal with respect to asthma exacerbations. However, more and longer studies are needed to better clarify the role of LTRAs and theophylline as add-on therapies.

Does bronchial hyperresponsiveness in asthma matter?

Bronchial hyperresponsiveness is a fundamental component of the asthmatic inflammatory process causing airway narrowing on exposure to a bronchoconstrictor stimulus. This in turn causes patients to experience symptoms of breathlessness, chest tightness, cough and wheeze. Bronchial challenge tests can be performed in the laboratory to establish the degree of bronchial hyperresponsiveness to both direct and indirect stimuli. The extent to which asthma pharmacotherapy attenuates bronchial hyperresponsiveness is therefore an important measure of efficacy. This review article discusses the effects of inhaled and oral asthma treatment upon bronchial hyperresponsiveness and highlights how, in conjunction with conventional measures of asthma control, it can be used as an aid to optimally manage patients.

Benefit-risk assessment of long-acting beta2-agonists in asthma

The use of a regular long-acting beta2-adrenoceptor agonists (beta2-agonists; LABA) is now established in asthma guidelines as the preferred option for second-line controller therapy in addition to inhaled corticosteroids. This has been driven by data showing beneficial effects of LABAs on exacerbation rates, in turn suggesting a putative corticosteroid-sparing effect. As LABAs are devoid of any clinically meaningful anti-inflammatory activity in vivo, their effects on exacerbations are presumably due to a diurnal stabilising effect on airway smooth muscle. LABAs have marked effects on symptoms and lung function, and this may make it difficult to assess anti-inflammatory control with inhaled corticosteroids when used in a combination inhaler such as fluticasone propionate/salmeterol or budesonide/formoterol. The use of fixed-dose combination inhalers is in many respects counter-intuitive to conventional teaching regarding flexible dosage titration with inhaled corticosteroids. It would therefore seem prudent first to gain optimal control of inflammation with inhaled corticosteroids before considering adding a LABA. Increasing the dosage of inhaled corticosteroids will have a relatively greater effect on exacerbations than on symptoms and lung function, whereas the converse applies when adding a LABA. Another option is to add a leukotriene receptor antagonist, which confers additional anti-inflammatory activity and is as effective on exacerbations as adding a LABA. Despite in vitro and ex vivo data showing a ligand-independent effect of LABAs on glucocorticoid receptor activation, clinical data do not indicate any relevant synergy between LABAs and inhaled corticosteroids when used together in the same inhaler. In particular, there is no evidence of potentiation by LABAs of the in vivo anti-inflammatory activity of inhaled corticosteroids that would suggest any genuine corticosteroid-sparing activity. Nonetheless, the data support the additive effects of inhaled corticosteroids and LABAs when used together due to their separate effects on inflammation and smooth muscle, respectively. Tolerance with LABAs is a predictable pharmacological phenomenon that occurs despite concomitant therapy with inhaled corticosteroids. Moreover, cross-tolerance also develops to short-acting beta2-agonists used for protection against bronchoconstrictor stimuli as a result of LABA-induced down-regulation, desensitisation and prolonged occupancy of beta2-adrenoceptors. The exact role of beta2-adrenoceptor polymorphism in determining tolerance with LABAs requires further prospective clinical studies evaluating long-term effects on outcomes such as exacerbations in patients with relevant genotypes and haplotypes. The next decade will provide challenging issues for clinicians with respect to defining further the role of LABAs as add-on controller therapy, particularly in evaluating the long-term effects of combination inhalers on inflammatory outcomes and airway remodelling.