Achieving asthma control in patients with moderate disease

What have we learnt about asthma control from trials of budesonide/formoterol as maintenance and reliever?

Despite improvements in medications, devices and understanding of the disease, about half of all asthma patients worldwide remain inadequately controlled, suggesting the need for a new approach to asthma management. Poor adherence to prescribed maintenance therapy and over-reliance on SABA reliever medication is a common cause of inadequate control. This article reviews published data from 6- to 12-month, double-blind, RCT and open-label real-world studies involving budesonide/formoterol maintenance and reliever therapy (MART) and relevant comparator approaches to asthma management, and considers how these compare in achieving the treatment goals described in guidelines. The data confirm that patients with asthma treated with budesonide/formoterol MART achieved the same or better asthma symptom control compared with ICS/LABA plus SABA regimens at similar or higher ICS doses, with consistently lower rates of exacerbations and considerably lower annual requirement for oral corticosteroids. These findings have been confirmed across a range of severities of persistent asthma. With the MART approach, maintenance dosing ensures coverage for day-to-day control, and the use of a reliever with anti-inflammatory properties (budesonide/formoterol) provides extra doses of ICS as soon as symptoms prompt the use of reliever, resulting in a 40-50% reduction of exacerbations compared with an ICS-based treatment approach plus as-needed SABA as reliever. As-needed, budesonide/formoterol has also recently been shown to be more effective as a reliever in mild asthma than SABA alone, reducing exacerbations by up to 64% in the SYGMA studies.

SKI3301, a purified herbal extract from Sophora tonkinensis, inhibited airway inflammation and bronchospasm in allergic asthma animal models in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Sophora tonkinensis (Leguminosae, ST) is a traditional herbal plant in Korea and China. Its roots and rhizomes have been used to dissipate heat, to clear toxic material and to treat acute pharyngolaryngeal infections and sore throats.

AIM OF STUDY

In this study, we tried to investigate the anti-inflammatory and anti-asthmatic effects of a purified extract (SKI3301) from Sophora tonkinensis using in vitro enzyme assay models and ovalbumin (OVA)-induced asthma animal models.

MATERIALS AND METHODS

The effect of SKI3301 on pro-inflammatory enzymes such as 5-lipoxygenase, phosphodiesterase 3 & 4, and thromboxane synthase was assayed in vitro. BALB/c mice were sensitized with OVA/Alum ip injection and nebulized with OVA to induce airway inflammation. Bronchoalveolar lavage (BAL) fluid was collected and analyzed for leukocytes infiltration and IL-5 production along with lung histopathology. Guinea pigs passively sensitized with anti-OVA antiserum were used to investigate the effect of SKI3301 on bronchospasm in vitro and in vivo.

RESULTS

SKI3301 potently inhibited the activities of 5-lipoxygenase, phosphodiesterase 3 & 4, and thromboxane synthase. Orally administered SKI3301 attenuated the total leukocytes and eosinophil infiltration and IL-5 level in BAL fluids. Histopathological changes associated with lung inflammation were also reduced by SKI3301. SKI3301 inhibited OVA-induced contraction of isolated trachea from sensitized guinea pigs. SKI3301 also protected OVA-induced bronchoconstriction in the sensitized guinea pigs. Maackiain, one of 3 major components of SKI3301, was effective in inhibiting 5-lipoxygenase and OVA-induced airway inflammation.

CONCLUSION

In this study, SKI3301 potently inhibited pro-inflammatory enzymes and attenuated OVA-induced bronchospasm in animal model of allergic asthma. These results suggest that SKI3301 may have therapeutic potential for allergic asthma.

Effects of ONO-6950, a novel dual cysteinyl leukotriene 1 and 2 receptors antagonist, in a guinea pig model of asthma

We assessed in this study the anti-asthmatic effects of ONO-6950, a novel cysteinyl leukotriene 1 (CysLT1) and 2 (CysLT2) receptors dual antagonist, in normal and S-hexyl glutathione (S-hexyl GSH)-treated guinea pigs, and compared these effects to those of montelukast, a CysLT1 selective receptor antagonist. Treatment with S-hexyl GSH reduced animals LTC4 metabolism, allowing practical evaluation of CysLT2 receptor-mediated airway response. ONO-6950 antagonized intracellular calcium signaling via human and guinea pig CysLT1 and CysLT2 receptors with IC50 values of 1.7 and 25 nM, respectively (human receptors) and 6.3 and 8.2 nM, respectively (guinea pig receptors). In normal guinea pigs, both ONO-6950 (1 or 0.3 mg/kg, p.o.) and the CysLT1 receptor antagonist montelukast (0.3 or 0.1 mg/kg, p.o.) fully attenuated CysLT1-mediated bronchoconstriction and airway vascular hyperpermeability induced by LTD4. On the other hand, in S-hexyl GSH-treated guinea pigs ONO-6950 at 3 mg/kg, p.o. or more almost completely inhibited bronchoconstriction and airway vascular hyperpermeability elicited by LTC4, while montelukast showed only partial or negligible inhibition of these airway responses. In ovalbumin sensitized guinea pigs, treatment with S-hexyl GSH on top of pyrilamine and indomethacin rendered antigen-induced bronchoconstriction sensitive to both CysLT1 and CysLT2 receptor antagonists. ONO-6950 strongly inhibited this asthmatic response to the level attained by combination therapy with montelukast and BayCysLT2RA, a selective CysLT2 receptor antagonist. These results clearly demonstrate that ONO-6950 is an orally active dual CysLT1/LT2 receptor antagonist that may provide a novel therapeutic option for patients with asthma.

Adherence: the goal to control asthma

Asthma management requires adequate adherence to many recommendations, including therapy, monitoring of asthma control, avoidance of environmental triggers, and attending follow-up appointments. Poor adherence is common in patients with asthma and is often associated with increased health care use, morbidity, and mortality. Many determinants of poor adherence have been identified and should be addressed, but there is no clear profile of the nonadherent patient. Interventions to improve adherence therefore demand tailoring to the individual by including patient-specific education, addressing patient fears and misconceptions, monitoring adherence, and developing a shared decision process.

Pharmacotherapy of patients with mild persistent asthma: strategies and unresolved issues

In studies comparing regular versus on-demand treatment for patients with mild persistent asthma, on-demand treatment seems to have a similar efficacy on clinical and functional outcomes, but it does not suppress chronic airway inflammation or airway hyper-responsiveness (AHR) associated with asthma. Data on the efficacy of a continuous treatment with inhaled corticosteroids (ICS) in preventing the progression of asthma are conflicting. There is the possibility that patients without a regular treatment with ICS may develop a more severe asthma associated with airway structural changes (remodeling) and a progressive loss of lung function. However, the possible clinical and functional consequences of persistent, not controlled, airway inflammation in patients with asthma have to be established. Assessment of asthma control should include inflammatory outcomes, such as fraction of exhaled nitric oxide and sputum eosinophil counts. Until the relationships between symptoms, lung function tests, AHR, airway inflammation, exacerbations, and airway remodeling are clarified, regular treatment seems to be generally more appropriate than on-demand treatment to warrant a greater control of asthma. Select subgroups of patients with mild asthma who are well controlled by regular treatment might adopt the on-demand treatment plan as an intermediate step toward the suspension of controller medication. The increasing evidence for heterogeneity of asthma, the growing emphasis on asthma subphenotypes, including molecular phenotypes identified by omics technologies, and their possible implications for different asthma severity and progression and therapeutic response, are changing the paradigm of treating patients with asthma only based on classification of their disease severity to a pharmacological strategy more focused on the individual asthmatic patient. Pharmacological treatment of asthma is going toward a personalized approach.

Leukotriene modifiers for asthma treatment

Leukotrienes (LTs), including cysteinyl LTs (CysLTs) and LTB(4) , are potent lipid mediators that have a role in the pathophysiology of asthma. At least two receptor subtypes for CysLTs, CysLT(1) and CysLT(2) , have been identified. The activation of the CysLT(1) receptor is responsible for most of the pathophysiological effects of CysLTs in asthma, including increased airway smooth muscle activity, microvascular permeability, and airway mucus secretion. LTB(4) might have a role in severe asthma, asthma exacerbations, and the development of airway hyperresponsiveness. CysLT(1) receptor antagonists can be given orally as monotherapy in patients with mild persistent asthma, but these drugs are generally less effective than inhaled glucocorticoids. Combination of CysLT(1) receptor antagonists and inhaled glucocorticoids in patients with more severe asthma may improve asthma control and enable the dose of inhaled glucocorticoids to be reduced while maintaining similar efficacy. The identification of subgroups of asthmatic patients who respond to CysLT(1) receptor antagonists is relevant for asthma management as the response to these drugs is variable. CysLT(1) receptor antagonists have a potential anti-remodelling effect that might be important for preventing or reversing airway structural changes in patients with asthma. This review discusses the role of LTs in asthma and the role of LT modifiers in asthma treatment.

Advances in pediatric asthma in 2010: addressing the major issues

Last year's "Advances in pediatric asthma" concluded with the following statement: "If we can close these [remaining] gaps through better communication, improvements in the health care system and new insights into treatment, we will move closer to better methods to intervene early in the course of the disease and induce clinical remission as quickly as possible in most children." This year's summary will focus on recent advances in pediatric asthma that take steps moving forward as reported in Journal of Allergy and Clinical Immunology publications in 2010. Some of these recent reports show us how to improve asthma management through steps to better understand the natural history of asthma, individualize asthma care, reduce asthma exacerbations, and manage inner-city asthma and some potential new ways to use available medications to improve asthma control. It is clear that we have made many significant gains in managing asthma in children, but we have a ways to go to prevent asthma exacerbations, alter the natural history of the disease, and reduce health disparities in asthma care. Perhaps new directions in personalized medicine and improved health care access and communication will help maintain steady progress in alleviating the burden of this disease in children, especially young children.

Role of Leukotrienes and Leukotriene Modifiers in Asthma

Leukotrienes (LTs), including cysteinyl LTs (CysLTs) and LTB₄, are potent lipid mediators that are pivotal in the pathophysiology of asthma phenotypes. At least two receptor subtypes for CysLTs - CysLT1 and CysLT₂ - have been identified. Most of the pathophysiological effects of CysLTs in asthma, including increased airway smooth muscle activity, microvascular permeability and airway mucus secretion, are mediated by the activation of the CysLT1 receptor. LTB₄ may have a role in the development of airway hyperresponsiveness, severe asthma and asthma exacerbations. Although generally less effective than inhaled glucocorticoids, CysLT₁ receptor antagonists can be given orally as monotherapy in patients with persistent mild asthma. In patients with more severe asthma, CysLT₁ receptor antagonists can be combined with inhaled glucocorticoids. This therapeutic strategy improves asthma control and enables the dose of inhaled glucocorticoids to be reduced, while maintaining similar efficacy. The identification of subgroups of patients with asthma who respond to CysLT₁ receptor antagonists is relevant for asthma management, as the response to these drugs is variable. The potential anti-remodeling effect of CysLT₁ receptor antagonists might be important for preventing or reversing airway structural changes in patients with asthma. This review discusses the role of LTs in asthma and the therapeutic implications of the pharmacological modulation of the LT pathway for asthma.