Ragweed immunotherapy in adult asthma

Cost-effectiveness of allergen immunotherapy

PURPOSE OF REVIEW

Allergic rhinitis is a relevant and global health problem affecting up to 5-50% of the general population and its prevalence is increasing due to climate change and pollution among other factors and counts among the 10 most frequent reasons for medical consultation, generating an important economic impact. Allergen immunotherapy (AIT) is the only allergy-disease-modifying treatment and there is plenty of evidence of its effectiveness with regards subcutaneous and oral routes of AIT.This narrative review article examines published literature in the last 24 months regarding the pharmacoeconomics of AIT versus standard of care treatment (SOC) for the treatment of allergic rhinitis and asthma.

RECENT FINDINGS

Farraia et al. assessed in 2022 subcutaneous immunotherapy (SCIT, _438/$500.28) and sublingual immunotherapy (SLIT) (_1021/$1116.19) plus symptomatic treatment versus SOC treatment in children with HDM-driven allergic asthma, measuring QALYs, decrease of medication, decrease of exacerbations and symptoms. They used the cost-effective threshold: _18 482.80 ($21 110.14), finding that AIT is cost-effective.Also, SCIT and SLIT plus symptomatic treatment was assessed versus SOC treatment in children with grass pollen allergic rhinitis. The authors concluded that SCIT (_933/$1065.67) and SLIT (_1408/ $1608.22) seem cost-effective, particularly SCIT.

SUMMARY

Allergen immunotherapy is cost-effective in the management of allergic rhinitis and asthma as compared with SOC alone. As most studies consider only during-treatment costs and no long-term benefits or preventive effects are being assessed, the real cost-effectiveness of allergen immunotherapy could be even higher.

Factors associated with aeroallergen testing among adults with asthma in a large health system

Background

Aeroallergen testing informs precision care for adults with asthma, yet the epidemiology of testing in this population remains poorly understood.

Objective

We sought to identify factors associated with receiving aeroallergen testing, the results of these tests, and subsequent reductions in exacerbation measures among adults with asthma.

Methods

We used electronic health record data to conduct a retrospective, observational cohort study of 30,775 adults with asthma who had an office visit with a primary care provider or an asthma specialist from January 1, 2017, to August 26, 2022. We used regression models to identify (1) factors associated with receiving any aeroallergen test and tests to 9 allergen categories after the index visit, (2) factors associated with positive test results, and (3) reductions in asthma exacerbation measures in the year after testing compared with before testing.

Results

Testing was received by 2201 patients (7.2%). According to multivariable models, receiving testing was associated with having any office visit with an allergy/immunology specialist during the study period (odds ratio [OR] = 91.3 vs primary care only [P < .001]) and having an asthma emergency department visit (OR = 1.62 [P = .004]) or hospitalization (OR = 1.62 [P = .03]) in the year before the index visit. Age 65 years or older conferred decreased odds of testing (OR = 0.74 vs age 18-34 years [P = .008]) and negative test results to 6 categories (P ≤ .04 for all comparisons). Black race conferred increased odds of testing (OR =1.22 vs White race [P = .01]) and positive test results to 8 categories (P < .04 for all comparisons). Exacerbation measures decreased after testing.

Conclusion

Aeroallergen testing was performed infrequently among adults with asthma and was associated with reductions in asthma exacerbation measures.

Subcutaneous allergen immunotherapy in the treatment of allergic respiratory disease

Subcutaneous immunotherapy is recognized as a cornerstone in the management of allergic respiratory disease in patients who are properly characterized with allergy and with allergic rhinoconjunctivis and/or well-controlled asthma, and who are willing to adhere to the rigorous treatment program. A key tenet is that it affords the opportunity to effect long-term clinical remission through its disease-modifying properties. Furthermore, it has the potential to prevent the progression of allergic rhinitis to asthma, prevent new allergen sensitivities, and improve a patient's quality of life.

Immunotherapy for Asthma

Asthma represents one of the biggest global health concerns with increasing prevalence and influence on global health. Several distinct asthma phenotypes have been identified with one of the most common, earliest recognized, and described being the allergic asthma phenotype, in which allergens trigger asthma through mechanisms involving allergen-specific immunoglobulin E (IgE). Allergen-specific immunotherapy (AIT), in the forms of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT), has been used for many decades as a tool for reducing IgE-mediated sensitization and controlling symptoms of allergic disease, most commonly for allergic rhinitis, and it remains the only currently available disease modifying therapy in atopic patients. AIT has been studied for use in mild to moderate allergic asthma. While the data are often inconsistent, and utilize a multitude of different methods, antigens, and outcome measures, in general, AIT may have several beneficial effects on asthma disease control, quality of life, and requirement for medication. These benefits are notable when immunotherapy is used as an adjunct to pharmacologic treatment in carefully selected and monitored patients with mild to moderate persistent asthma. Patients with severe asthma are excluded from these trials. Importantly, patients with asthma, and in particular severe asthma, may have a higher rate of systemic adverse reactions to SCIT, including anaphylaxis, however, these events are overall rare. Future research in the area is needed to definitively assess the benefit of SCIT and SLIT for patients with asthma, comparing outcomes with different methods, addressing the role of AIT in severe asthma, significance of multiallergen AIT in allergic asthma, and safety concerns in asthma.

Indonesia-Based Study of the Clinical and Cost-Saving Benefits of Subcutaneous Allergen Immunotherapy for Children with Allergic Rhinitis in Private Practice

BACKGROUND

Until now, the cost of allergy treatment in the insured public health care system and the non-insured self-financing private health care system in Indonesia has not been well documented and published, as well as the cost of allergy treatment with subcutaneous immunotherapy.

OBJECTIVE

To evaluate the clinical and cost benefits of allergic rhinitis treatment in children with subcutaneous immunotherapy in a non-insured self-financing private health care system.

METHODS

A retrospective cohort study conducted from 2015 until 2020 that compared the clinical improvement and health care costs over 18 months in newly diagnosed AR children who received SCIT versus matched AR control subjects who did not receive SCIT, with each group consisting of 1098 subjects.

RESULTS

A decrease in sp-HDM-IgE level (kU/mL) from 20.5 + 8.75 kU/mL to 12.1 + 3.07 kU/mL was observed in the SCIT group. To reduce the symptom score of allergic rhinitis by 1.0 with SCIT, it costs IDR 21,753,062.7 per child, and for non-SCIT, it costs IDR 104,147,878.0 per child. Meanwhile, to reduce the medication score (MS) by 1.0 with SCIT, it costs IDR 17,024,138.8, while with non-SCIT, it costs IDR 104,147,878.0. Meanwhile, to lower combination symptoms and medication score (CSMS) by 1.0, with SCIT, it costs IDR 9,550,126.6, while with non-SCIT, it costs IDR 52,073,938.9.

CONCLUSIONS

In conclusion, this first Indonesia-based study demonstrates substantial health care cost savings associated with SCIT for children with AR in an uninsured private health care system and provides strong evidence for the clinical benefits and cost-savings benefits of AR treatment in children.

Pharmacoeconomics of allergy immunotherapy versus pharmacotherapy

Introduction: The purpose of this review is to evaluate the cost-effectiveness of allergy immunotherapy (AIT) in the treatment of allergic rhinitis, asthma, and other allergic conditions.Area covered: An extensive search of the PubMed and Medline database (January 1996 up to June of 2020) was conducted using the search terms allergy immunotherapy, pharmacoeconomics, cost-effectiveness, allergic rhinitis, and asthma. Studies were included if they included information on the economics of AIT in comparison to pharmacotherapy in the treatment of allergic rhinitis or asthma either as actual costs or based on theoretical models. Systematic reviews were included if they included information about the cost-effectiveness of AIT.Most clinical trials found significant cost-savings with AIT. The cost-effective time-point ranged from a few months to several years after treatment initiation.. Cost savings were demonstrated as early as 3 months after treatment initiation and were as great as 80% less than SDT in some studies.Expert opinion: There is strong evidence in the collective literature that AIT is cost-effective as compared to SDT alone. The magnitude of AIT's cost-effectiveness is likely underestimated because most of the studies considered during treatment costs and not AIT's long-term benefits or preventive/prophylactic effects or its impact on co-morbid conditions.

2020 Focused Updates to the Asthma Management Guidelines: A Report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group

The 2020 Focused Updates to the Asthma Management Guidelines: A Report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group was coordinated and supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. It is designed to improve patient care and support informed decision making about asthma management in the clinical setting. This update addresses six priority topic areas as determined by the state of the science at the time of a needs assessment, and input from multiple stakeholders:A rigorous process was undertaken to develop these evidence-based guidelines. The Agency for Healthcare Research and Quality's (AHRQ) Evidence-Based Practice Centers conducted systematic reviews on these topics, which were used by the Expert Panel Working Group as a basis for developing recommendations and guidance. The Expert Panel used GRADE (Grading of Recommendations, Assessment, Development and Evaluation), an internationally accepted framework, in consultation with an experienced methodology team for determining the certainty of evidence and the direction and strength of recommendations based on the evidence. Practical implementation guidance for each recommendation incorporates findings from NHLBI-led patient, caregiver, and clinician focus groups. To assist clincians in implementing these recommendations into patient care, the new recommendations have been integrated into the existing Expert Panel Report-3 (EPR-3) asthma management step diagram format.

The Cost-Effectiveness of Allergen Immunotherapy Compared with Pharmacotherapy for Treatment of Allergic Rhinitis and Asthma

This article evaluates the cost-effectiveness of allergy immunotherapy (AIT) in the treatment of allergic rhinitis, asthma, and other allergic conditions. An extensive search of the PubMed and Medline databases (up to December 2018) was conducted. There is strong evidence in the collective literature, which included individual studies and systematic reviews, that AIT is cost-effective in the management of allergic rhinitis and asthma as compared with standard drug treatment alone. The magnitude of AIT's cost-effectiveness is likely underestimated because most of the studies considered during-treatment costs and not the long-term benefits or preventive or prophylactic effects of AIT.

EAACI Allergen Immunotherapy User's Guide

Allergen immunotherapy is a cornerstone in the treatment of allergic children. The clinical efficiency relies on a well-defined immunologic mechanism promoting regulatory T cells and downplaying the immune response induced by allergens. Clinical indications have been well documented for respiratory allergy in the presence of rhinitis and/or allergic asthma, to pollens and dust mites. Patients who have had an anaphylactic reaction to hymenoptera venom are also good candidates for allergen immunotherapy. Administration of allergen is currently mostly either by subcutaneous injections or by sublingual administration. Both methods have been extensively studied and have pros and cons. Specifically in children, the choice of the method of administration according to the patient's profile is important. Although allergen immunotherapy is widely used, there is a need for improvement. More particularly, biomarkers for prediction of the success of the treatments are needed. The strength and efficiency of the immune response may also be boosted by the use of better adjuvants. Finally, novel formulations might be more efficient and might improve the patient's adherence to the treatment. This user's guide reviews current knowledge and aims to provide clinical guidance to healthcare professionals taking care of children undergoing allergen immunotherapy.

Rational design of a hypoallergenic Phl p 7 variant for immunotherapy of polcalcin-sensitized patients

Polcalcins are important respiratory panallergens, whose IgE-binding capacity depends on the presence of calcium. Since specific immunotherapy is not yet available for the treatment of polcalcin-sensitized patients, we aimed to develop a molecule for efficient and safe immunotherapy. We generated a hypoallergenic variant of the grass pollen polcalcin Phl p 7 by introducing specific point mutations into the allergen’s calcium-binding regions. We thereby followed a mutation strategy that had previously resulted in a hypoallergenic mutant of a calcium-binding food allergen, the major fish allergen parvalbumin. Dot blot assays performed with sera from Phl p 7-sensitized patients showed a drastically reduced IgE reactivity of the Phl p 7 mutant in comparison to wildtype Phl p 7, and basophil activation assays indicated a significantly reduced allergenic activity. Rabbit IgG directed against mutant rPhl p 7 blocked patients’ IgE binding to wildtype Phl p 7, indicating the mutant’s potential applicability for immunotherapy. Mass spectrometry and circular dichroism experiments showed that the mutant had lost the calcium-binding capacity, but still represented a folded protein. In silico analyses revealed that the hypoallergenicity might be due to fewer negative charges on the molecule’s surface and an increased molecular flexibility. We thus generated a hypoallergenic Phl p 7 variant that could be used for immunotherapy of polcalcin-sensitized individuals.

Mind the gaps: Clinical trial concepts to address unanswered questions in aeroallergen immunotherapy-An NIAID/AHRQ Workshop

The Agency for Healthcare Research and Quality and the National Institute of Allergy and Infectious Diseases organized a workshop to develop trial concepts that could improve the use and effectiveness of aeroallergen immunotherapy (AAIT). Expert groups were formed to accomplish the following tasks: (1) propose a study design to compare the effectiveness and safety of subcutaneous versus sublingual AAIT; (2) propose a study design to compare the effectiveness and safety of AAIT by using 1 or a few allergens versus all or most allergens to which a patient is sensitized; (3) propose a study design to determine whether AAIT can alter the progression of childhood allergic airways disease; and (4) propose a study design to determine the optimal dose and duration of AAIT to achieve maximal effectiveness with acceptable safety. Study designs were presented by the workgroups, extensively discussed at the workshop, and revised for this report. The proposed trials would be of long duration and require large highly characterized patient populations. Scientific caveats and feasibility matters are discussed. These concepts are intended to help the development of clinical trials that can address some of the major questions related to the practice of AAIT for the management and prevention of allergic airways disease.

Ragweed sublingual tablet immunotherapy: part I - evidence-based clinical efficacy and safety

Sublingual tablet immunotherapy provides an attractive alternative approach to allergen immunotherapy, as the allergen is administered as a rapidly dissolving sublingual tablet. Part I of this two-part series on the ragweed sublingual tablet describes the dose-ranging clinical work, the safety studies and the clinical outcomes from the pivotal trials which provide clear evidence for statistically significant and clinically meaningful benefit in the treatment of patients suffering from ragweed-induced seasonal allergic rhinitis-conjunctivitis with or without milder asthma. The robust results observed in the clinical trials performed with the ragweed sublingual tablet are defined by the quality of their study design, their use of a standardized allergen extract, their consistent reproducibility in demonstrating therapeutic efficacy and their properly quantified and graded safety data.

Evidence-based dosing of maintenance subcutaneous immunotherapy: a contemporary review of state-of-the-art practice

BACKGROUND

Subcutaneous immunotherapy is an effective allergy treatment only if properly dosed. In this article we review the data on the probable effective dose range for subcutaneous immunotherapy and convert the recommended doses into a clinically relevant format.

METHODS

A comprehensive literature search of dose-response subcutaneous immunotherapy studies was done of EBM databases, Medline database, PreMedline, and the National Guideline Clearinghouse for the period 1980-2016. Recommended doses were converted to the volume of allergen extract that should be added to a 5-mL maintenance vial.

RESULTS

A safe and effective dose for subcutaneous immunotherapy is likely 5-20 μg of major allergen per injection. A 0.5-mL injection from a 5-mL maintenance vial containing 0.2 mL of manufacturer's extract of each allergen should reach the lower end of the probable effective dose range for most allergens. A larger volume of extract is required to reach that range when treatment includes cat, dog, or only 1 dust mite. Increasing beyond the commonly prescribed 0.2 mL of manufacturer's extract added to a 5-mL treatment vial is reasonable for nearly all allergens to achieve a maintenance dose higher in the probable effective dose range.

CONCLUSION

Current otolaryngic allergy practice usually escalates patients to 0.5-mL injections from 5-mL maintenance vials containing 0.2 mL of manufacturer's extract of each allergen. With the main exceptions of cat and dog, those injections administered 1 or 2 times per month likely provide an efficacious dose of allergen and are consistent with published guidelines. A larger volume of extract should be considered in certain clinical situations.

EAACI Guidelines on Allergen Immunotherapy: Allergic rhinoconjunctivitis

Allergic rhinoconjunctivitis (AR) is an allergic disorder of the nose and eyes affecting about a fifth of the general population. Symptoms of AR can be controlled with allergen avoidance measures and pharmacotherapy. However, many patients continue to have ongoing symptoms and an impaired quality of life; pharmacotherapy may also induce some side-effects. Allergen immunotherapy (AIT) represents the only currently available treatment that targets the underlying pathophysiology, and it may have a disease-modifying effect. Either the subcutaneous (SCIT) or sublingual (SLIT) routes may be used. This Guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on AIT for AR and is part of the EAACI presidential project "EAACI Guidelines on Allergen Immunotherapy." It aims to provide evidence-based clinical recommendations and has been informed by a formal systematic review and meta-analysis. Its generation has followed the Appraisal of Guidelines for Research and Evaluation (AGREE II) approach. The process included involvement of the full range of stakeholders. In general, broad evidence for the clinical efficacy of AIT for AR exists but a product-specific evaluation of evidence is recommended. In general, SCIT and SLIT are recommended for both seasonal and perennial AR for its short-term benefit. The strongest evidence for long-term benefit is documented for grass AIT (especially for the grass tablets) where long-term benefit is seen. To achieve long-term efficacy, it is recommended that a minimum of 3 years of therapy is used. Many gaps in the evidence base exist, particularly around long-term benefit and use in children.

Allergen immunotherapy for allergic asthma: A systematic review and meta-analysis

BACKGROUND

To inform the development of the European Academy of Allergy and Clinical Immunology's (EAACI) Guidelines on Allergen Immunotherapy (AIT) for allergic asthma, we assessed the evidence on the effectiveness, cost-effectiveness and safety of AIT.

METHODS

We performed a systematic review, which involved searching nine databases. Studies were screened against predefined eligibility criteria and critically appraised using established instruments. Data were synthesized using random-effects meta-analyses.

RESULTS

98 studies satisfied the inclusion criteria. Short-term symptom scores were reduced with a standardized mean difference (SMD) of -1.11 (95% CI -1.66, -0.56). This was robust to a prespecified sensitivity analyses, but there was evidence suggestive of publication bias. Short-term medication scores were reduced SMD -1.21 (95% CI -1.87, -0.54), again with evidence of potential publication bias. There was no reduction in short-term combined medication and symptom scores SMD 0.17 (95% CI -0.23, 0.58), but one study showed a beneficial long-term effect. For secondary outcomes, subcutaneous immunotherapy (SCIT) improved quality of life and decreased allergen-specific airway hyperreactivity (AHR), but this was not the case for sublingual immunotherapy (SLIT). There were no consistent effects on asthma control, exacerbations, lung function, and nonspecific AHR. AIT resulted in a modest increased risk of adverse events (AEs). Although relatively uncommon, systemic AEs were more frequent with SCIT; however no fatalities were reported. The limited evidence on cost-effectiveness was mainly available for sublingual immunotherapy (SLIT) and this suggested that SLIT is likely to be cost-effective.

CONCLUSIONS

AIT can achieve substantial reductions in short-term symptom and medication scores in allergic asthma. It was however associated with a modest increased risk of systemic and local AEs. More data are needed in relation to secondary outcomes, longer-term effectiveness and cost-effectiveness.

Healthcare costs for allergic rhinitis patients on allergy immunotherapy: a retrospective observational study

OBJECTIVE

Subcutaneous immunotherapy (SCIT) for allergic rhinitis (AR) has been shown to control symptoms for up to several years following treatment discontinuation, but the effect of SCIT on healthcare costs for commercially insured patients is unknown. The objective of this study was to compare healthcare costs and resource utilization for patients with AR who received SCIT compared with those who discontinued SCIT shortly after initiation.

METHODS

This retrospective cohort study evaluated medical and pharmacy claims from the Optum Research Database from January 2009 through February 2014 for adults and pediatric patients with >7 (continuers) vs. ≤7 (discontinuers) injection visits for SCIT within 60 days of initiation.

RESULTS

After 1:1 propensity score matching, each cohort included 6710 patients. Continuers were less likely than discontinuers to use oral corticosteroids (27.7% vs. 29.6%, p = .018), or to have ≥1 respiratory-related emergency room visit (5.4% vs. 6.5%, p = .008) and ≥1 inpatient stay (1.1% vs. 1.7%; p = .002). Continuers were more likely than discontinuers to have ≥1 AR-related office (98.8% vs. 94.6%, p < .001) or outpatient visit (2.4% vs. 1.7%, p = .002). Continuers had greater mean total AR-related costs than discontinuers ($1918 vs. $646, p < .001). Unadjusted mean total respiratory-related costs were lower for continuers than discontinuers, although the difference was not statistically significant ($1589 vs. $1785, p = .077); when adjusted with a generalized linear model, these costs were significantly lower among continuers (p < .001).

CONCLUSIONS

Continued SCIT use is associated with decreased emergency room visits and inpatient stays, decreased oral corticosteroid use, and lower respiratory-related costs, compared with early discontinuation.

The SQ House Dust Mite SLIT-Tablet Is Well Tolerated in Patients with House Dust Mite Respiratory Allergic Disease

BACKGROUND

The SQ house dust mite (HDM) SLIT-tablet (ALK, Denmark) addresses the underlying cause of HDM respiratory allergic disease, and a clinical effect has been demonstrated for both HDM allergic rhinitis and allergic asthma. Here, we present pooled safety data from an adult population with HDM respiratory allergy, with particular focus on the impact of asthma on the SQ HDM SLIT-tablet tolerability profile.

METHODS

Safety data from 2 randomised double-blind, placebo-controlled clinical trials were included: MT-04: 834 adults with HDM allergic asthma not well controlled by inhaled corticosteroids and with HDM allergic rhinitis, and MT-06: 992 adults with moderate-to-severe HDM allergic rhinitis despite the use of allergy pharmacotherapy and with or without asthma.

RESULTS

The proportion of subjects experiencing adverse events (AEs) was greater in the active treatment group (12 SQ-HDM; 73% of subjects) compared to placebo (53%). The most common treatment-related AEs were local allergic reactions. No AEs were reported as systemic allergic reactions. Regardless of asthma status, most AEs were mild or moderate (>97% of AEs) and the frequency of serious AEs was low. Subgroup analysis revealed no statistically significant difference in the risk of experiencing moderate or severe treatment-related AEs for subjects with asthma compared to subjects without asthma (p = 0.88). In addition, subjects with partly controlled or uncontrolled asthma were no more likely to experience moderate or severe treatment-related AEs than subjects with controlled asthma (p = 0.42).

CONCLUSION

The SQ HDM SLIT-tablet is well tolerated, and the safety profile was comparable for subjects with HDM respiratory allergic disease irrespective of asthma status.

Allergen immunotherapy for allergic asthma: a systematic overview of systematic reviews

Background

There is clinical uncertainty about the effectiveness and safety of allergen immunotherapy (AIT) for the treatment of allergic asthma.

Objectives

To undertake a systematic overview of the effectiveness, cost-effectiveness and safety of AIT for the treatment of allergic asthma.

Methods

We searched nine electronic databases from inception to October 31, 2015. Systematic reviews were independently screened by two reviewers against pre-defined eligibility criteria and critically appraised using the Critical Appraisal Skills Programme quality assessment tool for systematic reviews. Data were descriptively and thematically synthesized.

Results

We identified nine eligible systematic reviews; these focused on delivery of AIT through the following routes: subcutaneous (SCIT; n = 3); sublingual (SLIT; n = 4); and both SCIT and SLIT (n = 2). This evidence found that AIT delivered by SCIT and SLIT can improve medication and symptom scores and measures of bronchial hyper-reactivity. The impact on measures of lung function or asthma control was however less clear. We found no systematic review level evidence on the cost-effectiveness of SCIT or SLIT. SLIT had a favorable safety profile when compared to SCIT, particularly in relation to the risk of systemic reactions.

Conclusions

AIT has the potential to achieve reductions in symptom and medication scores, but there is no clear or consistent evidence that measures of lung function can be improved. Bearing in mind the limitations of synthesizing evidence from systematic reviews and the fact that these reviews include mainly dated studies, a systematic review of current primary studies is now needed to update this evidence base, estimate the effectiveness of AIT on asthma outcomes and to investigate the relative effectiveness, cost-effectiveness and safety of SCIT and SLIT.

International Consensus on Allergen Immunotherapy II: Mechanisms, standardization, and pharmacoeconomics

This article continues the comprehensive international consensus (ICON) statement on allergen immunotherapy (AIT). The initial article also recently appeared in the Journal. The conclusions below focus on key mechanisms of AIT-triggered tolerance, requirements in allergen standardization, AIT cost-effectiveness, and regulatory guidance. Potential barriers to and facilitators of the use of AIT are described in addition to future directions. International allergy specialists representing the European Academy of Allergy and Clinical Immunology; the American Academy of Allergy, Asthma & Immunology; the American College of Allergy, Asthma and Immunology; and the World Allergy Organization critically reviewed the existing literature and prepared this summary of recommendations for best AIT practice. The authors contributed equally and reached consensus on the statements presented herein.

Allergy immunotherapy in reducing healthcare cost

PURPOSE OF REVIEW

To evaluate the cost-effectiveness of allergen immunotherapy (AIT) in the treatment of allergic rhinitis and asthma. Individual studies and systematic reviews that included information on AIT economic outcomes as compared with symptomatic drug treatment (SDT) were evaluated.

RECENT FINDINGS

One systematic review that included 14 studies concluded that subcutaneous and sublingual immunotherapy may be cost-effective compared with SDT from around 6 years. Another systematic review of 24 studies comparing economic outcomes of subcutaneous allergy immunotherapy and/or sublingual allergy immunotherapy with SDT found compelling evidence for cost-savings with both forms of AIT over SDT. There was no strong evidence indicating superior cost-efficacy of subcutaneous allergy immunotherapy or sublingual allergy immunotherapy over SDT in either of these systematic reviews. Individual studies have demonstrated AIT cost-savings as high as 80% compared with SDT. Significant cost-savings were reported as early as 3 months after AIT initiation. In some studies, cost-efficacy time-point was not established until after treatment discontinuation - presumably due to time required for the clinical benefits to outweigh the AIT treatment costs. Although some economic modeling studies included the costs of 'asthma prevented', the collective literature of AIT economics provides very little to no information about the cost benefits of the preventive aspect of AIT.

SUMMARY

Overall, individual studies and systematic reviews provide strong evidence for the cost-effectiveness of AIT over SDT. The magnitude of cost-efficacy is likely underestimated in that few studies consider the cost-savings due to AIT's long-term benefits or preventive effect.

Allergen Immunotherapy (AIT): a prototype of Precision Medicine

Precision medicine is a medical model aiming to deliver customised healthcare - with medical decisions, practices, and/or products tailored to the individual patient informed but not directed by guidelines. Allergen immunotherapy has unique immunological rationale, since the approach is tailored to the specific IgE spectrum of an individual and modifies the natural course of the disease as it has a persistent efficacy after completion of treatment. In this perspective Allergen Immunotherapy - AIT has to be presently considered a prototype of Precision Medicine.

Precise information and biomarkers provided by systems medicine and network medicine will address the discovery of Allergen immunotherapy biomarkers for (i) identification of the causes, (ii) stratification of eligible patients for AIT and (iii) the assessment of AIT efficacy.

This area of medical technology is evolving rapidly and, compelemented by e-health, will change the way we practice medicine. It will help to monitor patients’ disease control and data for (i) patient stratification, (ii) clinical trials, (iii) monitoring the efficacy and safety of targeted therapies which are critical for reaching an appropriate reimbursement. Biomarkers associated with e-health combined with a clinical decision support system (CDSS) will change the scope of Allergen immunotherapy.

The cost/effectiveness of Allergen immunotherapy is a key issue for successful implementation. It should include the long-term benefits in the pharmaco-economic evaluation, since no other allergy treatment has this specific characteristic.

AIT is the prototype of current and future precision medicine.

Primary Care of the Patient with Asthma

Obstructive lung disease includes asthma and chronic obstructive pulmonary disease (COPD). Because a previous issue of Medical Clinics of North America (2012;96[4]) was devoted to COPD, this article focuses on asthma in adults, and addresses some topics about COPD not addressed previously. Asthma is a heterogeneous disease marked by variable airflow obstruction and bronchial hyperreactivity. Onset is most common in early childhood, although many people develop asthma later in life. Adult-onset asthma presents a particular challenge in the primary care clinic because of incomplete understanding of the disorder, underreporting of symptoms, underdiagnosis, inadequate treatment, and high rate of comorbidity.

Asthma medications should be available for over-the-counter use: con

The United States Food and Drug Administration recently considered a policy to transfer inhaled short-acting bronchodilators to over-the-counter status if conditions of safe use can be established. The American Thoracic Society filed a comment in opposition to the proposal. This article examines the negative consequences that might result from allowing nonprescription access to bronchodilators and other inhaled asthma medications. Such a proposed policy change conflicts directly with current guidelines for asthma management and would undermine efforts to achieve adequate asthma control in patients. In addition, a policy change to convert asthma medications to over-the-counter status could result in increased costs to patients as well as increased health care costs to society overall due to a worsening of asthma control in the population.

Allergy immunotherapy: what is the evidence for cost saving?

PURPOSE OF REVIEW

Given the widespread prevalence of allergic disease, its substantially associated clinical and economic burden, the unique disease-modifying benefits of allergy immunotherapy (AIT), and increased availability of sublingual immunotherapy (SLIT), a critical update of the evidence for AIT-related cost savings [for both subcutaneous immunotherapy (SCIT) and SLIT] is particularly relevant and timely. The present article reviews the evidence for SCIT-related and SLIT-related cost savings derived from a systematic review of the published literature.

RECENT FINDINGS

Examined were 24 publications pertaining to the health economics of AIT. Except for one early study comparing the costs of AIT to symptomatic drug treatment (SDT), the remainder provide compelling evidence for AIT cost savings (whether SCIT or SLIT) over SDT. Furthermore, of the six studies comparing cost outcomes of SLIT to SCIT, four reported cost savings favoring SLIT.

SUMMARY

This review, spanning research from Southern Europe, Scandinavia, Northern Europe, North America, and the Czech Republic, encompasses a range of perennial and seasonal allergic conditions, including allergic asthma, allergic rhinitis with or without asthma, and rhinoconjunctivitis with or without allergic rhinitis due to house dust mite, grass or ragweed pollen, or a mixture of various allergens. All but one study compellingly demonstrate cost savings conferred by AIT over SDT.

Examining mediators of housing mobility on adolescent asthma: results from a housing voucher experiment

Literature on neighborhood effects on health largely employs non-experimental study designs and does not typically test specific neighborhood mediators that influence health. We address these gaps using the Moving to Opportunity (MTO) housing voucher experiment. Research has documented both beneficial and adverse effects on health in MTO, but mediating mechanisms have not been tested explicitly. We tested mediation of MTO effects on youth asthma (n = 2829). MTO randomized families living in public housing to an experimental group receiving a voucher to subsidize rental housing, or a control group receiving no voucher, and measured outcomes 4-7 years following randomization. MTO had a harmful main effect vs. controls for self-reported asthma diagnosis (b = 0.24, p = 0.06), past-year asthma attack (b = 0.44, p = 0.02), and past-year wheezing (b = 0.17, p = 0.17). Using Inverse Odds Weighting mediation we tested mental health, smoking, and four housing dimensions as potential mediators of the MTO-asthma relationship. We found no significant mediation overall, but mediation may be gender-specific. Gender-stratified models displayed countervailing mediation effects among girls for asthma diagnosis by smoking (p = 0.05) and adult-reported housing quality (p = 0.06), which reduced total effects by 35% and 42% respectively. MTO treatment worsened boys' mental health and mental health reduced treatment effects on asthma diagnosis by 27%. Future research should explore other potential mediators and gender-specific mediators of MTO effects on asthma. Improving measurement of housing conditions and other potential mediators may help elucidate the "black box" of neighborhood effects.

Safety of immunotherapy in patients with rhinitis, asthma or atopic dermatitis using an ultra-rush buildup. A retrospective study

BACKGROUND

Allergen-specific immunotherapy is a proven, highly effective treatment for IgE-mediated diseases. However, ultra-rush immunotherapy is prescribed infrequently because of the perception that accelerated immunotherapy buildup leads to a higher rate of systemic reactions.

OBJECTIVE

To evaluate the frequency of adverse reactions in patients with IgE-mediated diseases receiving house dust mite (HDM) ultra-rush immunotherapy.

METHODS

A retrospective, observational study was conducted for patients with IgE-mediated diseases receiving allergen-specific immunotherapy. Subcutaneous immunotherapy with depigmented polymerized mites extract was administered in two refracted doses of 0.2 and 0.3 ml at first injection, and in single 0.5 ml doses in subsequent monthly injections. A 30 min observation time was required after each injection. Systemic reactions were graded using the World Allergy Organisation grading system.

RESULTS

575 patients were included. The age range was 1-83 years. Most patients had respiratory diseases (544) and 101 patients had atopic dermatitis. A total of 27 patients (4.6%) experienced 139 reactions (reactions/injections: 1.9%); 22 patients (3.8%) experienced 134 local reactions (local reactions/injections: 1.8%). Eight patients (1.3%) experienced eight systemic reactions (systemic reactions/injections: 0.1%). Five systemic reactions were grade 2 and three grade 1. Two systemic reactions were reported during buildup. There were no fatalities.

CONCLUSION

Taking into account the possible bias for the retrospective design of this study we observed that immunotherapy for patients with IgE-mediated diseases using a depigmented polymerized mites extract, with an ultra-rush buildup, has similar frequency of systemic reactions than that seen in slower buildup immunotherapy in other studies. Accelerated buildup could improve patients' adherence and reduce dropout rates.

Effect of inhaled inactivated Mycobacterium phlei in children with moderate asthma

Bacillus Calmette-Guérin and other mycobacterial vaccines are important therapeutic methods in a series of chronic inflammatory disorders characterized by Th1/Th2 imbalance in which Th2 type cells and cytokines often increase. However, few studies have investigated whether it can reduce or prevent the symptoms and attacks in children with asthma. This study evaluated the effect of inactivated Mycobacterium phlei inhaled by an atomizing device placed on asthmatic children. In this randomized, single-center, Seretide-controlled study, children aged 4-12 years with newly diagnosed, moderate, persistent asthma were treated with either inhaled inactivated M. phlei or inhaled Seretide patch. The efficacy of inhaled inactivated M. phlei was related with the alleviation of asthma symptoms, improvement of lung function and reduction of bronchial hyper-responsiveness and total serum IgE, which was similar with Seretide. These findings may have important clinical value in confirming inhaled inactivated M. phlei as a new therapeutic method in moderately asthmatic children.

Effectiveness of subcutaneous immunotherapy for allergic rhinoconjunctivitis and asthma: a systematic review

OBJECTIVES/HYPOTHESIS

To systematically review the effectiveness and safety of subcutaneous immunotherapy (SCIT) for treatment of allergic rhinoconjunctivitis and asthma, using formulations currently approved in the United States.

STUDY DESIGN

We searched the following databases up to May 21, 2012: MEDLINE, Embase, LILACS, and the Cochrane Central Register of Controlled Trials.

METHODS

We included randomized controlled trials published in English comparing SCIT to placebo, pharmacotherapy, or other SCIT regimens that reported clinical outcomes of interest. Studies of adults or mixed age populations were included. Studies were excluded if the diagnosis of allergy and/or asthma was not confirmed with objective testing. Paired reviewers selected articles for inclusion and extracted data. We assessed the risk of bias for each study and graded the strength of evidence for each outcome as high, moderate, or low.

RESULTS

Sixty-one studies met our inclusion criteria. Majority of the studies (66%) evaluated single-allergen immunotherapy regimens. The literature provides high-grade evidence that SCIT reduces asthma symptoms, asthma medication usage, rhinitis/rhinoconjunctivitis symptoms, conjunctivitis symptoms, and rhinitis/rhinoconjunctivitis disease-specific quality of life in comparison to placebo or usual care. There is moderate evidence that SCIT decreases rhinitis/rhinoconjunctivitis medication usage. Respiratory reactions were the most common systemic reaction. There were few reports of anaphylaxis; no deaths were reported.

CONCLUSIONS

Generally moderate to strong evidence supports the effectiveness of SCIT for treatment of allergic rhinitis and asthma, particularly with single-allergen immunotherapy regimens. Adverse reactions to SCIT are common, but no deaths were reported in the included studies.

Randomized controlled trial of a ragweed allergy immunotherapy tablet in North American and European adults

BACKGROUND

In North America and Europe, millions of patients experience symptoms of allergic rhinitis with or without conjunctivitis (AR/C) on exposure to ragweed pollen. The disease burden can be significant, with most patients relying on symptomatic medications without disease-modifying potential. However, novel sublingual immunomodulatory treatment options may potentially play an important role if efficacy and side effect profiles allow the convenience of self-administration.

OBJECTIVES

This study evaluated an allergy immunotherapy tablet (AIT; SCH 39641/MK-3641) for treatment of ragweed-induced AR/C in the first large randomized, double-blind multinational trial of this therapeutic modality for ragweed allergy.

METHODS

Adults (n = 784) with short ragweed-induced AR/C were randomly assigned to approximately 52 weeks of daily self-administered ragweed AIT of 1.5, 6, or 12 units of Ambrosia artemisiifolia major allergen 1 (Amb a 1-U) or placebo. Subjects could use as-needed allergy rescue medication. Symptoms and medications were recorded daily. The primary efficacy end point was total combined daily symptom/medication score (TCS) during peak ragweed season. Safety was monitored through adverse event diaries maintained through study duration.

RESULTS

During peak ragweed season, ragweed AIT of 1.5, 6, and 12 Amb a 1-U reduced TCS by 9% (-0.76; P = .22), 19% (-1.58; P = .01), and 24% (-2.04; P = .002) compared with placebo. During the entire season, ragweed AIT of 1.5, 6, and 12 Amb a 1-U reduced TCS by 12% (-0.88; P = .09), 18% (-1.28; P = .01), and 27% (-1.92; P < .001) compared with placebo. Treatment was well tolerated; no systemic allergic reactions occurred.

CONCLUSIONS

In this trial, ragweed AIT of 12 Amb a 1-U was effective and tolerable with a safety profile that permitted daily self-administration of ragweed allergen immunotherapy.

The cost-effectiveness of immunotherapy for respiratory allergy: a review

This article reviews the international literature on the cost-effectiveness of immunotherapy for respiratory allergy. Included studies conducted an economic evaluation of immunotherapy for allergic rhinoconjunctivitis, allergic conjunctivitis, allergic rhinitis, asthma or allergic rhinitis in combination with asthma. Although there were few economic evaluations and these suffered from methodological shortcomings, the evidence appears to support the cost-effectiveness of immunotherapy as compared with pharmacotherapy for allergic rhinoconjunctivitis, subcutaneous immunotherapy as compared with pharmacotherapy for allergic rhinitis and immunotherapy as compared with pharmacotherapy for allergic rhinitis and asthma. One economic evaluation suggested that immunotherapy as compared with pharmacotherapy is unlikely to be cost-effective for asthma. The questions of the cost-effectiveness of sublingual vs subcutaneous immunotherapy and of the cost-effectiveness of immunotherapy for allergic conjunctivitis have not been resolved to date. The cost-effectiveness of immunotherapy depends on the duration of the clinical benefit of immunotherapy following treatment cessation, and on the break-even point of cumulative costs between immunotherapy and pharmacotherapy. There is a need for economic evaluations based on high-quality prospective and long-term clinical studies comparing immunotherapy with pharmacotherapy in real-life practice and comparing sublingual with subcutaneous immunotherapy.

Allergen immunotherapy in allergic respiratory diseases: from mechanisms to meta-analyses

Allergen-specific immunotherapy (SIT) involves the repeated administration of allergenic extracts to atopic individuals over a period of 3 to 5 years either subcutaneously (SCIT) or sublingually (SLIT) for the treatment of allergic respiratory diseases, including asthma and allergic rhinitis (AR). In studies, SCIT and SLIT have been shown to improve existing symptoms of asthma and AR and to also have the capability to cause disease-modifying changes of the underlying atopic condition so as to prevent new allergic sensitization as well as arrest progression of AR to asthma. Recent evidence suggests that immunotherapy brings about these effects through actions that use T-regulatory cells and blocking antibodies such as IgG(4) and IgA(2,) which can then result in an "immune deviation" from a T-helper (Th) 2 cell pattern to a Th1 cell pattern. Numerous meta-analyses and studies have been performed to evaluate the existing data among these studies, with the consensus recommendation favoring the use of immunotherapy because of its potential to modify existing diseases. Significant adverse reactions can occur with immunotherapy, including anaphylaxis and, very rarely, death. A primary factor in considering SIT is its potential to provide long-lasting effects that are able to be sustained well after its discontinuation. Given the significant burden these allergic diseases impose on the health-care system, SIT appears to be a cost-effective adjunctive treatment in modifying the existing disease state.

CpG oligodeoxynucleotides as TLR9 agonists: therapeutic application in allergy and asthma

Unmethylated cytosine-phosphate-guanine (CpG) dinucleotides in microbial DNA sequences activate Toll-like receptor (TLR) 9, and previous studies have shown that oligodeoxynucleotides (ODNs) containing CpG in specific base sequence motifs (CpG ODNs) can reiterate the majority of the immunomodulatory effects produced by bacterial DNA. Many of the manifestations in allergic diseases are primarily due to T helper (T(h))-2 cell-type responses. CpG ODNs can induce T(h)1 and T-regulatory (T(reg)) cell-type cytokines that can suppress the T(h)2 response. The therapeutic application of TLR9 has been explored extensively in recent years, and many studies are being conducted to assess the safety and efficacy of TLR9 agonists in various diseases, including atopic and infectious diseases, and cancer. Studies in murine models have shown that the development of atopic airway disease can be prevented by treatment with CpG ODNs. Various clinical trials are currently ongoing to determine the efficacy of CpG ODNs as a therapeutic tool for atopic diseases. In this review, we discuss the therapeutic application of CpG ODNs in allergy and asthma. CpG ODNs may be used alone or as an adjuvant to immunotherapy to treat these disorders.

Injection allergen immunotherapy for asthma

BACKGROUND

Allergen specific immunotherapy has long been a controversial treatment for asthma. Although beneficial effects upon clinically relevant outcomes have been demonstrated in randomised controlled trials, there remains a risk of severe and sometimes fatal anaphylaxis. The recommendations of professional bodies have ranged from cautious acceptance to outright dismissal. With increasing interest in new allergen preparations and methods of delivery, we updated the systematic review of allergen specific immunotherapy for asthma.

OBJECTIVES

The objective of this review was to assess the effects of allergen specific immunotherapy for asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trials Register up to 2005, Dissertation Abstracts and Current Contents.

SELECTION CRITERIA

Randomised controlled trials using various forms of allergen specific immunotherapy to treat asthma and reporting at least one clinical outcome.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed eligibility of studies for inclusion. Two authors independently performed quality assessment of studies.

MAIN RESULTS

Eighty-eight trials were included (13 new trials). There were 42 trials of immunotherapy for house mite allergy; 27 pollen allergy trials; 10 animal dander allergy trials; two Cladosporium mould allergy, two latex and six trials looking at multiple allergens. Concealment of allocation was assessed as clearly adequate in only 16 of these trials. Significant heterogeneity was present in a number of comparisons. Overall, there was a significant reduction in asthma symptoms and medication, and improvement in bronchial hyper-reactivity following immunotherapy. There was a significant improvement in asthma symptom scores (standardised mean difference -0.59, 95% confidence interval -0.83 to -0.35) and it would have been necessary to treat three patients (95% CI 3 to 5) with immunotherapy to avoid one deterioration in asthma symptoms. Overall it would have been necessary to treat four patients (95% CI 3 to 6) with immunotherapy to avoid one requiring increased medication. Allergen immunotherapy significantly reduced allergen specific bronchial hyper-reactivity, with some reduction in non-specific bronchial hyper-reactivity as well. There was no consistent effect on lung function. If 16 patients were treated with immunotherapy, one would be expected to develop a local adverse reaction. If nine patients were treated with immunotherapy, one would be expected to develop a systemic reaction (of any severity).

AUTHORS' CONCLUSIONS

Immunotherapy reduces asthma symptoms and use of asthma medications and improves bronchial hyper-reactivity. One trial found that the size of the benefit is possibly comparable to inhaled steroids. The possibility of local or systemic adverse effects (such as anaphylaxis) must be considered.

Economic evaluation of sublingual immunotherapy vs. symptomatic treatment in allergic asthma

BACKGROUND

The worldwide increased prevalence of allergic diseases, and especially of respiratory allergy, is paralleled by increased health costs. This requires consideration of the cost to efficacy ratio of the available treatment to identify the optimal choice.

OBJECTIVE

To compare the different economic relevance, over a long evaluation time, of symptomatic pharmacologic therapy and sublingual immunotherapy (SLIT) in patients with allergic asthma.

METHODS

Seventy patients with perennial allergic asthma, sensitized to dust mites, were enrolled; 50 of these patients were treated with SLIT against house dust mites and 20 were treated with symptomatic drugs. The patients were evaluated for 2 years after discontinuing immunotherapy, which was performed for 3 years, to obtain a more complete follow-up. Symptom scores, medication scores, and all other direct medical costs were evaluated with a specific questionnaire.

RESULTS

Patients treated with SLIT plus drugs had a higher mean annual cost in the first year of SLIT treatment compared with patients only receiving drug treatment, but the mean annual cost became significantly lower since the end of SLIT both in the whole population and in the subgroups defined by disease severity.

CONCLUSION

The economic advantage measured alongside this prospective observational study was long lasting and still present at the fifth year of the follow-up (2 years after discontinuing SLIT) and could positively be related to the persistent good clinical control of patients.

A review of allergen-specific immunotherapy in human and veterinary medicine

This article reviews allergen-specific immunotherapy in human and veterinary medicine. Current hypotheses of possible mechanisms of actions are outlined. Indications, success rates, adverse effects and factors influencing outcome of therapy are discussed in humans, dogs, cats and horses.

Combination treatment with omalizumab and rush immunotherapy for ragweed-induced allergic rhinitis: Inhibition of IgE-facilitated allergen binding

BACKGROUND

The combination of anti-IgE (omalizumab) therapy with ragweed injection immunotherapy for seasonal allergic rhinitis results in a significant reduction in systemic side effects and enhanced efficacy compared with immunotherapy alone. One proposed mechanism of immunotherapy is to induce regulatory antibodies that inhibit facilitated antigen presentation.

OBJECTIVES

We sought to determine whether the combination protocol has a cumulative effect on inhibition of facilitated antigen presentation both during and after discontinuation of treatment.

METHODS

Ragweed allergen immunotherapy with and without omalizumab therapy was tested in a 4-arm, double-blind, placebo-controlled study. Flow cytometry was used to detect serum inhibitory activity for IgE-facilitated CD23-dependent allergen binding to B cells as a surrogate marker for facilitated antigen presentation. Serum ragweed-specific IgG4 was measured by means of ELISA.

RESULTS

Immunotherapy alone resulted in partial inhibition of allergen-IgE binding after 5 to 19 weeks of treatment compared with baseline (P < .01). Complete inhibition of allergen-specific IgE binding was observed in both treatment groups receiving omalizumab (P < .001). Allergen-specific IgG4 levels were only increased after immunotherapy (P < .05), both in the presence and absence of anti-IgE treatment. Combined treatment resulted in the induction of long-lasting inhibitory antibody function for up to 42 weeks compared with either treatment alone.

CONCLUSION

Ragweed immunotherapy induced serum regulatory antibodies that partially blocked binding of allergen-IgE complexes to B cells. Additional treatment with anti-IgE, by directly blocking IgE binding to CD23, completely inhibited allergen-IgE binding.

CLINICAL IMPLICATIONS

The combination of ragweed immunotherapy and anti-IgE resulted in prolonged inhibition of allergen-IgE binding compared with either treatment alone, events that might contribute to enhanced efficacy.

Early and late phase asthmatic response in lower airways of cat-allergic asthmatic patients--a comparison between experimental and environmental allergen challenge

BACKGROUND

Standardized experimental allergen challenges are usually adopted to investigate the effect of allergen exposure on the lower airways. Environmental (natural) allergen challenges are used less often, mainly because of difficulties in standardizing the method, safety reasons and costs. The aim of this study was to investigate the relationship between an experimental and an environmental bronchial challenge. For this reason a natural challenge model was developed.

METHODS

Sixty-two patients with a history of cat allergen-induced symptoms involving the lower airways, positive skin prick test, positive in vitro specific IgE to cat allergen and bronchial hyper-responsiveness were included. All 62 patients underwent an experimental challenge in the laboratory followed by an environmental allergen challenge.

RESULTS

All 62 patients developed an early asthmatic response [>or=20% fall in forced expiratory volume in 1 s (FEV1)] in the experimental challenge and 60% (37/62) during the environmental challenge. A late asthmatic response (>or=15% fall in FEV1 within 3-24 h) was seen in 56% (35/62) of the patients after the experimental challenge. Following the environmental challenge 47% (29/62) of the patients developed a late response. Thirty-four per cent (21/62) of the patients developed a late response in both challenge models and 31% (19/62) did not develop a late response in any model. Thus, there was consistency in 65% (40/62) of the patients in both challenge models.

CONCLUSION

We found consistency in the pattern of response to inhaled allergen between the two challenge models and we believe that experimental bronchial challenge is likely to reflect the development of relevant inflammation in the lower airways after low-dose allergen exposure in the environment.