Drug treatment of asthma in the 1990s: achievements and new strategies

Inhibitory effects of diterpene acids from root of Aralia cordata on IgE-mediated asthma in guinea pigs

This study evaluated the anti-asthmatic activities of four diterpene acids isolated from Aralia cordata root that are proposed to be the active ingredients in its traditional use as a treatment for inflammation, overheating, pain and spasm in Korea. The diterpene acids were identified as kaurenoic acid, 7-oxo-sandaracopimaric acid, 17-hydroxy-ent-kaur-15-en-19-oic acid, and hederagenin, by comparing their phytochemical and spectroscopic data with previous reports. The effects of diterpene acids on asthma were evaluated by determining the specific airway resistance (sRaw) during the immediate asthmatic response (IAR) and the late-phase asthmatic response (LAR) in guinea pigs with IgE-mediated asthma. Recruitment of leukocytes and the presence of chemical mediators in bronchoalveolar lavage fluid (BALF) were determined, and histopathological surveys performed. The four diterpene acids dosed at 25 approximately 100 mg/kg had dose-dependently anti-asthmatic effects: 7-oxo-sandaracopimaric acid > 17-hydroxy-ent-kaur-15-en-19-oic acid > kaurenoic acid > hederagenin. 7-oxo-sandaracopimaric acid (25 mg/kg) significantly (p < 0.05) inhibited sRaw by 59.5% in IAR and LAR, and also dose-dependently inhibited recruitment of eosinophils and neutrophils into lung and release of chemical mediators, histamine, and the activity of phospholipase A(2) and eosinophil peroxidase in BALF. 7-Oxo-sandaracopimaric acid had the highest activity among the diterpene acids. But its effect was lower than cromolyn sodium, salbutamol, or dexamethasone in both the IAR and the LAR. These results suggested that C(7)-oxo radical of 7-oxo-sandaracopimaric acid was more active than the C(7)-hydroxy and hydrogen of the other compounds, and showed diterpene acids have anti-asthmatic effects, supporting the traditional application of this herb in treating IgE-mediated asthma.

Anti-asthmatic activity of phenolic compounds from the roots of Gastrodia elata Bl

We previously reported that 4-hydroxy-3-methoxybenzaldehyde has the most potent anti-inflammatory and analgesic activity of eight phenolic compounds obtained from the dried roots of Gastrodiaelata (GE) Blume (Orchidaceae); its activity may be related to inhibition of cyclooxygenase activities and oxidation. In the present study, the effects of nine phenolic compounds from GE on immediate-phase (IAR) and late-phase (LAR) asthmatic responses after aerosolized-ovalbumin (OA) challenge were evaluated by determining the specific airway resistance (sRaw) using a double-chambered plethysmograph in conscious guinea pigs with IgE-mediated asthma. Furthermore, recruitment of leukocytes, histamine release, and eosinophil peroxidase (EPO) and phospholipase A(2) (PLA(2)) activities were determined in bronchoalveolar lavage fluids (BALF) 24h after the antigen challenge. 4-Hydroxy-3-methoxybenzyl alcohol (12.5mg/kg) significantly (p<0.05) inhibited sRaw in IAR and in LAR by 51.97+/-4.96% and 39.93+/-3.46%, respectively, compared to that of the controls. Further, hydroxy-3-methoxybenzyl alcohol significantly (p<0.05) inhibited recruitment of leukocytes in accordance with amelioration of eosinophilia and neutrophilia, histamine (30.66+/-5.20%), EPO activity (21.58+/-2.02%), and specific PLA(2) activity (16.60+/-2.52%) in BALF compared with the control. In addition, bis-(4-hydroxyphenyl) methane, 4-hydroxy-3-methoxybenzoic acid, and 4-hydroxy-3-methoxybenzaldehyde (12.5mg/kg) significantly (p<0.05) inhibited sRaw, while bis-(4-hydroxyphenyl) methane, benzyl alcohol, and 4-hydroxybenzaldehyde at 12.5mg/kg significantly (p<0.05) inhibited leukocytes, histamine, EPO and PLA(2) activities in BALF compared with the controls. The phenolic glycoside, parishin had less activity compared to aglycones, 4-hydroxybenzyl compounds. These results suggest that the C(4) hydroxy and C(3) methoxy radicals in benzyl alcohols and aldehydes play important roles in mediating the anti-asthmatic activities of these compounds.

Allergens in the pathogenesis of asthma: potential role of anti-immunoglobulin E therapy

Evidence suggests that allergy is a significant triggering factor in asthma in children and adults alike. In immunoglobulin (Ig) E-mediated allergic reactions, sensitization occurs when allergen-specific B cells are stimulated and switched to IgE antibody production by interleukin (IL)-4 and IL-13 provided by helper T cells type 2 (Th2). The IgE antibodies act by arming cells bearing either the high-affinity (FcepsilonRI) or low-affinity (FcepsilonRII or CD23) receptor. The subsequent interaction of allergen with IgE-FcepsilonRI complexes on mast cells and basophils causes cross-linking of receptors that triggers the release of a variety of inflammatory mediators, cytokines and chemokines. Therefore, the ability to lower circulating free IgE levels is desirable because most individuals are exposed to multiple allergens to which they are sensitive at any given time. Omalizumab (formerly known as rhuMAb-E25) is a recently developed humanized monoclonal anti-IgE antibody directed at the FcepsilonRI binding domain of human IgE. It inhibits binding of IgE to mast cells without provoking mast cell activation. Preliminary clinical data from randomized controlled trials have shown that the addition of omalizumab to standard asthma therapy reduces asthma exacerbations and decreases inhaled corticosteroid and rescue medication use. The compound is also well tolerated. Omalizumab represents a novel therapeutic approach in the management of asthma.

Factors affecting UK primary-care costs of managing patients with asthma over 5 years

OBJECTIVE

To determine the effect of age, disease severity and compliance on the annual primary-care cost of managing patients with asthma initially on British Thoracic Society British Guidelines on Asthma Management (BGAM) treatment steps 2/3 over 5 years.

DESIGN AND SETTING

A modelling study performed from the perspective of the UK's National Health Service (NHS). STUDY PARTICIPANTS AND INTERVENTIONS: A data set was created comprising 4519 patients with asthma in the DIN-link database who were prescribed twice-daily inhaled corticosteroids and who were on steps 2/3 between 1 January and 31 December 1993. These patients were followed over 5 years.

METHODS

Asthma-related primary-care resource utilisation data obtained from the DIN-link database were stratified by patients' age, compliance and BGAM treatment step. Unit costs at 1999-2000 prices were applied to the resource use estimates to determine the mean annual cost per patient.

MAIN OUTCOME MEASURES AND RESULTS

High compliance with inhaled corticosteroids was not associated with a reduction in use of other primary-care resources, although the ratio of the number of prescriptions for inhaled corticosteroids to that for short-acting beta(2)-agonists increased, suggesting that patients' asthma was better controlled. Overall, the primary-care cost of managing a patient starting on steps 2/3 was found to be most strongly influenced by whether that patient moved onto steps 4/5 or continued to be managed on the same treatment step. If a patient continued to be managed at steps 2/3, costs were influenced in descending order of impact by compliance, previous BGAM step and the patient's age.

CONCLUSIONS

Better compliance with inhaled corticosteroids is likely to lead to better asthma control and fewer asthma attacks. Notwithstanding this, increasing compliance is likely to increase primary-care costs. Consequently increasing healthcare expenditure may be the inevitable consequence of improving asthma control.

Efficacy of budesonide in inhaled corticosteroid-naive patients and patients with mild persistent asthma

BACKGROUND

Patients with mild intermittent or mild persistent asthma represent 70% of asthma sufferers. Inhaled corticosteroids (ICSs) are the mainstay of treatment for persistent asthma, although many of the early clinical studies of these drugs included only patients with moderate to severe asthma.

OBJECTIVE

This article reviews the literature on the efficacy of budesonide in the treatment of mild persistent asthma, including newly diagnosed ICS-naive patients.

METHODS

Published data were identified by a MEDLINE search of the English-language literature from 1992 to 2002 using the terms budesonide plus efficacy or safety, both with and without the termsfluticasone or beclomethasone. An AstraZeneca reference database was also used to identify publications from the same period. Controlled, randomized studies that included patients with mild persistent asthma and early-treatment intervention were selected for inclusion.

RESULTS

Inhaled budesonide has been used for almost 20 years in the treatment and control of moderate to severe asthma. Studies involving patients with mild persistent asthma have demonstrated significant improvements in peak expiratory flow (PEF) rates (P < 0.01) and forced expiratory volume in I second (P < 0.016) values for adult, adolescent, and pediatric patients treated with budesonide compared with placebo. Budesonide therapy is effective when given once or twice daily via dry powder inhaler or nebulizer, even at a low starting dose (200 microg/d). No significant adverse events have been reported with budesonide within the dose range used to treat mild persistent asthma (200 to 400 microg/d). Significant improvements in PEF rates (P < 0.01) and significant reductions in the risk of exacerbations and the number of days with poorly controlled asthma have been reported for ICS-naive patients treated with budesonide compared with placebo (both P < 0.001). In the primary care setting, mild persistent asthma may be undertreated. Patients with mild persistent asthma benefit significantly from early treatment with budesonide (P < 0.05).

CONCLUSIONS

Budesonide is effective and well tolerated in the treatment of mild persistent asthma in adults and children, including many patients whose primary care physicians do not think they require daily ICS treatment.

Phosphodiesterase 4 inhibitors as novel anti-inflammatory agents

Preclinical and clinical studies of phosphodiesterase 4 inhibitors have shown that these agents may find utility in a wide range of inflammatory disorders, including asthma, chronic obstructive pulmonary disease, atopic dermatitis, rheumatoid arthritis, multiple sclerosis and various neurological disorders. The future of this class of drugs will depend upon the ability to demonstrate a reasonable safety margin against emesis and other typical phosphodieserase (PDE4) side effects, as well as in identification of the inflammatory disorder(s) most relevant to PDE4 inhibition.