Is there a role for immunotherapy in the treatment of asthma? Yes

Steroid-sparing effects with allergen-specific immunotherapy in children with asthma: a randomized controlled trial

BACKGROUND

Asthma control is now recognized as the main goal of asthma therapy. Guidelines recommend finding the lowest effective dose of inhaled corticosteroids in children with persistent asthma.

OBJECTIVE

The aim of this study was to investigate the efficacy of an allergen-specific immunotherapy with a high-dose hypoallergenic mite preparation (allergoid) as steroid-sparing agent in children with allergic asthma.

METHODS

Sixty-five children with asthma (Global Initiative for Asthma treatment levels II and III; 6-17 years old), after reaching asthma control with inhaled steroids during a 5-month baseline period, were randomized for subcutaneous mite allergoid immunotherapy (SCIT) plus fluticasone propionate (FP) or FP therapy alone for 2 years. During 2 subsequent 5-month winter periods, steroid therapy was adjusted according to predefined dose steps, determining and comparing the changes in FP dosages and the lowest FP dose sufficient to maintain asthma control. Immunologic and functional investigations were also carried out.

RESULTS

Children treated with house dust mite SCIT plus FP were able to significantly reduce the FP dose by more steps (P < .05), compared with the control group on FP alone. The mean daily dose in the immunotherapy group decreased from 330.3 μg in the baseline period to 151.5 μg after 2 treatment years, whereas in the control group the dose decreased from 290.6 μg to 206.3 μg. Compared with the control group, significant improvement was also observed in morning peak expiratory flow (P = .0315). Significantly increased levels of specific IgG(1) (P = .0001) and IgG(4) (P < .0001) were also observed.

CONCLUSION

Adding a mite allergoid SCIT to pharmacologic treatment is an effective and safe strategy to reduce corticosteroid doses while maintaining disease control in children with mite-induced allergic asthma.

Allergen-specific immunotherapy in allergic rhinitis and asthma. Mechanisms and proof of efficacy

Appeared at the beginning of the 20th century, allergen-specific immunotherapy (SIT) has long been used in allergic rhinitis and asthma without any knowledge of its mechanisms of action or any tangible proof of its efficacy. However, from the beginning of the era of evidence-based medicine, a number of placebo-controlled studies have been published and reached a sufficient number to assess the cellular events induced by SIT and allow meta-analysis to provide guidelines based on proofs. Controlled studies and meta-analysis concerned not only subcutaneous immunotherapy but also the sublingual route, demonstrating an effect of SIT on symptoms and medication use. Most recently sublingual tablets were proposed in allergic rhinitis. This paper reviews the mechanisms of SIT, the evidence of efficacy of SIT from the injective to the sublingual route and reminds the current guidelines.

Links between rhinitis and asthma

There is compelling evidence of a close relationship between the upper and lower airways in asthma and rhinitis. Rhinitis is present in the majority of patients with asthma, and a significant minority of patients with rhinitis have concomitant asthma. Similarities between the two conditions occur in the nature of the inflammation present in the target tissues. A common initiating step in the inflammatory process of allergic airways disease is the presence of immunoglobulin E providing an adaptor molecule between the offending allergen and inflammatory cell activation and mediator release. Differences in the two conditions arise largely from the structural differences between the nose and the lungs. In an asthmatic, concomitant allergic rhinitis increases healthcare costs and further impairs quality of life. The presence of rhinitis should always be investigated in children and young adults with asthma. Subjects with allergic rhinitis have an increased risk of developing asthma and may form a suitable population for secondary intervention to interrupt the 'allergic march'.

Treatment of established asthma in a murine model using CpG oligodeoxynucleotides

Allergen immunotherapy is an effective but underutilized treatment for atopic asthma. We have previously demonstrated that CpG oligodeoxynucleotides (CpG ODN) can prevent the development of a murine model of asthma. In the current study, we evaluated the role of CpG ODN in the treatment of established eosinophilic airway inflammation and bronchial hyperreactivity in a murine model of asthma. In this model, mice with established ovalbumin (OVA)-induced airway disease were given a course of immunotherapy (using low doses of OVA) in the presence or absence of CpG ODN. All mice then were rechallenged with experimental allergen. Untreated mice developed marked airway eosinophilia and bronchial hyperresponsiveness, which were significantly reduced by treatment with OVA and CpG. CpG ODN leads to induction of antigen-induced Th1 cytokine responses; successful therapy was associated with induction of the chemokines interferon-gamma-inducible protein-10 and RANTES and suppression of eotaxin. Unlike previous studies, these data demonstrate that the combination of CpG ODN and allergen can effectively reverse established atopic eosinophilic airway disease, at least partially through redirecting a Th2 to a Th1 response.

Efficacy of combination treatment with anti-IgE plus specific immunotherapy in polysensitized children and adolescents with seasonal allergic rhinitis

BACKGROUND

Specific immunotherapy (SIT) and treatment with monoclonal anti-IgE antibody have complementary modes of action.

OBJECTIVE

The purpose of this study was to determine whether combined therapy could provide better efficacy than either treatment alone.

METHODS

We conducted a randomized, double-blinded trial to assess the efficacy and safety of subcutaneously administered anti-IgE (omalizumab) or placebo in children and adolescents with seasonal allergic rhinitis in both a birch pollen season and a grass pollen season (sequential seasons together lasting an average of 84 days). There were 4 treatment arms. Each subject was started on SIT-birch or SIT-grass, and anti-IgE or placebo was started before and maintained during the anticipated pollen seasons (a total of 24 weeks). The primary efficacy variable was symptom load, the sum of daily symptom severity score plus rescue medication use.

RESULTS

A total of 221 subjects (intent-to-treat population) aged 6 to 17 years were analyzed for efficacy. Combination therapy reduced symptom load over the 2 pollen seasons by 48% (P <.001) over SIT alone. When analyzed separately by season, the 2 groups receiving unrelated SIT were considered placebo controls. In the grass season, symptom loads were as follows: unrelated (birch) SIT + placebo, 0.89 (reference value); unrelated (birch) SIT + anti-IgE, 0.49 (-45%); SIT-grass + placebo, 0.61 (-32%); SIT-grass + anti-IgE, 0.26 (-71%).

CONCLUSION

Anti-IgE therapy conferred a protective effect independent of the type of allergen. Additional clinical benefit was demonstrated in both pollen seasons, whether there was coverage by SIT or not. This combination might prove useful for the treatment of allergic rhinitis, particularly for polysensitized patients.

Specific immunotherapy in rhinitis and asthma

OBJECTIVE

The primary objective of this review is to discuss the efficacy of immunotherapy on combined lung and nasal symptoms, as well as data suggesting that allergen-specific immunotherapy (SIT) may, by altering the natural course of allergic disease, have a preventive effect on rhinitis and asthma.

DATA SOURCES

A review of literature published on allergen-specific immunotherapy in the treatment of allergic rhinitis and asthma was performed. The review represents a synthesis of these sources and the expert opinion of the author.

STUDY SELECTION

The expert opinion of the authors was used to select the relevant data for the review.

RESULTS

Epidemiologic studies have consistently shown that asthma and rhinitis often co-exist in the same patients, and rhinitis often precedes the onset of asthma. SIT has been shown to be effective as a curative treatment for these allergic diseases, but there is increasing evidence indicating that SIT also may have a preventive effect. A study of children monosensitized to house dust mites showed that immunotherapy altered the natural course of allergy in preventing the development of additional sensitizations.

CONCLUSIONS

At present, SIT seems to be the only treatment that may modify the course of the disease, either by preventing the development of new sensitivities or by altering the natural history of asthma. When SIT is introduced to patients with only allergic rhinoconjunctivitis, it may stop the development of asthma. SIT should be started early in the disease process, as soon as allergy has been diagnosed, to modify the spontaneous long-term progress of the allergic inflammation and disease.

Children with difficult asthma: a practical approach

Many open studies investigating the effects of innovative treatments for steroid-dependent asthma demonstrate some benefit. This is also true of the majority of placebo arms in placebo-controlled trials. This suggests that children with difficult asthma benefit from the high level of input that is typically provided in clinical trials, with or without additional medication. Such intensive management of patients, with the emphasis on establishing the diagnosis, improving adherence, and identifying provoking factors, is the key to optimizing asthma control for these children. For patients with genuinely severe asthma, despite high doses of conventional treatment, a greater understanding of the pathological basis of persistent symptoms is needed. Identification of different pathological subtypes of severe asthma should allow for more rational prescribing of asthma therapy, as well as the design of further trials of potential steroid-sparing treatments.

Economic evaluation of specific immunotherapy versus symptomatic treatment of allergic rhinitis in Germany

OBJECTIVE

To use published data to compare the economic consequences of specific immunotherapy (SIT) lasting 3 years with those of continuous symptomatic treatment in patients with either pollen or mite allergy.

DESIGN AND SETTING

The evaluation was conducted from the following 3 perspectives in Germany: (i) society; (ii) healthcare system; and (iii) statutory health insurance (SHI) provider. A modelling approach was used which was based on secondary analysis of existing data. The follow-up period was 10 years. The break-even point of cumulated costs, their difference per patient and the additional cost per additional patient free from asthma symptoms [incremental cost-effectiveness ratio (ICER)] were used as target variables, each from the viewpoint of SIT. The types of costs were direct and indirect (society), direct (healthcare system) and those incurred by SHI (i.e. expenses). In the base-case analysis, the average values of the clinical parameters and average case-related costs/expenses were applied.

MAIN OUTCOME MEASURES AND RESULTS

The break-even point was reached between year 6 and year 8 after the start of therapy, resulting in net savings of between 650 and 1190 deutschmarks (DM) per patient after 10 years. The ICERs of SIT were between -DM3640 and -DM7410, depending on study perspective and nature of the allergy (1990 values for symptomatic treatment and treatment of asthma, 1995 values for SIT; DM1 approximately $US0.58). The sensitivity analysis demonstrated the robustness of the model and its results. First, all the independent variables of the model were varied. Secondly, the influence of the model variables was quantified using a deterministic model. SIT was more likely to result in net savings than in additional costs. An economic parameter (cost for symptomatic treatment) had the highest influence on the results.

CONCLUSIONS

This evaluation showed that SIT for 3 years is economically advantageous in patients who are allergic to pollen or mites and whose symptoms are inadequately controlled by continuous symptomatic treatment. After 10 years, the administration of SIT leads to net savings from the perspectives of society, the healthcare system and SHI (third-party payer) in Germany.

Cutting Edge: Modulation of Airway Inflammation by CpG Oligodeoxynucleotides in a Murine Model of Asthma

Asthma has been increasing in industrialized countries. Evidence suggests that asthma is caused by a Th2 immune response to inhaled environmental Ags and that childhood infections protect against this. We have shown that bacterial DNA contains motifs, centered on unmethylated CpG dinucleotides, which induce Th1-type responses. We hypothesized that the Th1 effect of these CpG motifs may oppose the Th2 type allergic response and suggest that this may account for the protective effect of childhood infection against asthma. We examined the effects of CpG-motif oligodeoxynucleotides (CpG ODN) in a murine model of asthma. Airway eosinophilia, Th2 cytokine induction, IgE production, and bronchial hyperreactivity were prevented by coadministration of CpG ODN with the Ag. Significantly, in a previously sensitized mouse, CpG ODN can prevent allergen-induced airway inflammation. These studies suggest that exposure to CpG DNA may protect against asthma.