Effective treatment of house dust mite-induced allergic rhinitis with 2 doses of the SQ HDM SLIT-tablet: Results from a randomized, double-blind, placebo-controlled phase III trial

Immunotherapy With the SQ Tree SLIT-tablet in Adults and Adolescents With Allergic Rhinoconjunctivitis

PURPOSE

The SQ tree sublingual immunotherapy (SLIT)-tablet containing allergen extracts with the major allergen Bet v 1 from birch pollen is currently being developed for the treatment of tree pollen-induced allergic rhinitis/conjunctivitis with or without asthma. The aim of this Phase II trial was to investigate the dose-related efficacy and safety of the SQ tree SLIT-tablet.

METHODS

This study was a randomized, parallel-group, double-blind, placebo-controlled, multi-national trial conducted in Europe. A total of 637 participants were randomized equally to receive placebo or treatment with the SQ tree SLIT-tablet in doses of 0.5, 1, 2, 4, 7, or 12 development units (DU). Treatment was initiated ~16 weeks before onset of the 2013 birch pollen season (BPS) and was continued throughout the BPS with a total duration of at least 6 months. During the BPS and tree pollen season (TPS), subjects assessed rhinoconjunctivitis symptoms and medication use on a daily basis in an electronic diary; weekly assessments of rhinoconjunctivitis quality of life were also made.

FINDINGS

Analysis of the average daily symptom score during the BPS and the TPS showed that the difference between active treatment and placebo was statistically significant for the 7 DU group (BPS, P = 0.02; TPS, P = 0.03), with no clear dose-response relationship. All doses of the SQ tree SLIT-tablet induced changes from baseline in birch-specific IgE and IgG₄ that were statistically significant compared with placebo at all time points assessed (P < 0.0001) with a clear dose-response relationship for birch specific IgG₄. In general, the SQ tree SLIT-tablet was well tolerated, with the majority of treatment-related adverse events (≥95%) being mild or moderate in severity. The most frequently reported treatment-related adverse events were generally related to the sublingual administration of the tablet (ie, they occurred in the oral cavity).

IMPLICATIONS

The results from this trial suggest that the SQ tree SLIT-tablet in doses up to 12 DU has a tolerability profile suitable for at-home administration. The immunomodulatory changes indicate a dose-response relationship, but clinical efficacy parameters were inconclusive, probably due to low pollen counts, emphasizing the importance of pollen exposure for the outcome of a pollen allergy immunotherapy trial. EudraCT no: 2012-000031-59.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Challenges in the implementation of EAACI guidelines on allergen immunotherapy: A global perspective on the regulation of allergen products

Regulatory approaches for allergen immunotherapy (AIT) products and the availability of high-quality AIT products are inherently linked to each other. While allergen products are available in many countries across the globe, their regulation is very heterogeneous. First, we describe the regulatory systems applicable for AIT products in the European Union (EU) and in the United States (US). For Europe, a depiction of the different types of relevant procedures, as well as the committees involved, is provided and the fundamental role of national agencies of the EU member states in this complex and unique network is highlighted. Furthermore, the regulatory agencies from Australia, Canada, Japan, Russia, and Switzerland provided information on the system implemented in their countries for the regulation of allergen products. While AIT products are commonly classified as biological medicinal products, they are made available by varying types of procedures, most commonly either by obtaining a marketing authorization or by being distributed as named patient products. Exemptions from marketing authorizations in exceptional cases, as well as import of allergen products from other countries, are additional tools applied by countries to ensure availability of needed AIT products. Several challenges for AIT products are apparent from this analysis and will require further consideration.

Advances in environmental and occupational disorders in 2016

In this review we highlight recent studies that advance the knowledge and understanding of the effects of various environmental factors and associated immune responses in patients with allergic diseases. This review will focus on new literature regarding allergic and immune responses to a variety of environmental factors, including aeroallergens, stinging insects, fungi, pollutants, viral respiratory tract infections, climate change, and microbial exposures.

Effect of grass sublingual tablet immunotherapy is similar in children and adults: A Bayesian approach to design pediatric sublingual immunotherapy trials

BACKGROUND

Large sample sizes are needed for sublingual immunotherapy (SLIT) trials because of inherent data variability secondary to inconsistent allergen exposure. Obtaining large sample sizes for pediatric SLIT trials is challenging, but a Bayesian approach using prior adult data can reduce the necessary sample size.

OBJECTIVE

We sought to describe how a Bayesian framework using prior information from adult trials can be used to improve pediatric SLIT clinical development.

METHODS

Data were compiled by using a frequentist approach (conventional clinical trial approach independent of prior data) from trials conducted during the clinical development of timothy grass SLIT-tablets.

RESULTS

The treatment effect of timothy grass SLIT-tablets was considered similar between pediatric (n = 795) and adult (n = 2299) data pools, with relative total combined symptom plus medication score improvement versus placebo of 21% (95% CI, 11.0% to 30.4%) and 20% (95% CI, 14.6% to 24.4%), respectively. Phleum pratense-specific IgG₄ and IgE-blocking factor increased from baseline in both children and adults treated with timothy grass SLIT-tablets. Given the reasonable assumption in similarity of treatment response between adults and children, a Bayesian approach is described to demonstrate rigorous efficacy criteria for pediatric trials incorporating information from prior adult trials and thereby reduce the sample size.

CONCLUSIONS

Data support the similarity of efficacy and immunologic changes between children and adults treated with SLIT for allergic rhinoconjunctivitis. Therefore it is appropriate to use data from adult trials to design feasible trials in children, which might reduce unsafe off-label use by promoting more quickly proper labeling of approved products.

Tablet-based sublingual immunotherapy for respiratory allergy

Allergic respiratory disease represents a significant and expanding health problem worldwide. The gold standard of therapeutic intervention is still grucocorticosteroids, although they are not effective in all patients and may cause side effects. Allergen Immunotherapy has been administrated as subcutaneous injections for treatment of allergic rhinoconjunctivitis and asthma and has been practiced for the past century. Sublingual immunotherapy (SLIT) tablets are now available for grass- or ragweed-induced rhinoconjunctivitis and will be available in Spain for house dust mite (HDM)-induced rhinoconjunctivitis and asthma in the next months. In this review, new developments in the field of tablet-based SLIT for respiratory allergy are summarized, with special emphasis on HDM-induced allergic rhinitis and asthma. SLIT tablets are the best-documented immunotherapy products on the market and represent a more patient-friendly concept because they can be self-administrated at home.

[Adjuvants]

It is estimated that only 5% of all patients who can principally benefit from specific immunotherapy (SIT) undergo this treatment. SIT represents the only curative treatment for allergic disorders and efficacy has been demonstrated with various allergens. There is an urgent demand for the development of safe preparations with enhanced efficacy achievable by only a few administrations. Adjuvants are pharmacological or immunological acting molecules modifying the specific immunological response to allergens. In vaccine technology, adjuvants are broadly used to enhance immunogenicity of highly purified antigens with low immune stimulating activity. Adjuvants may target to a retarded allergen release, a modulation of the immune system, or can be used as vector systems to transport allergens and adjuvants effectively to target cells.

Sublingual Immunotherapy Dosing Regimens: What Is Ideal?

Sublingual immunotherapy (SLIT) is a treatment for allergic respiratory diseases that has demonstrated efficacy and safety. Several formulations of SLIT are now available worldwide for treatment of allergic rhinitis (AR). Grass tablets containing 15 to 25 μg of group 5 major allergen reduced combined AR symptoms and medication use by 23% to 41% in 3 treatment years and 2 follow-up years. Ragweed pollen tablets (12 μg of Ambrosia artemisiifolia 1) and liquid extracts (50 μg of Ambrosia artemisiifolia 1) reduced combined AR symptoms and medication use by 26% and 43%, respectively. House dust mite tablets containing 300 index of reactivity (16 μg of Dermatophagoides pteronyssinus 1 and 68 μg of Dermatophagoides farinae 1) reduced AR symptoms by 17.9% and 17.0% in 1 treatment year and 1 follow-up year, respectively. A different house dust mite tablet (12 standardized quality house dust mite) was able to reduce the risk of asthma exacerbation compared with placebo (hazard ratio, 0.69; 95% CI, 0.50-0.96). Most adverse events were local and mild to moderate in severity. For SLIT products reviewed herein, effective doses range from 1.12 to 84 μg of major allergen(s). However, allergen content is not uniformly standardized, can be expressed in arbitrary or proprietary units (depending on the manufacturer), and assays for determination of allergen content are highly variable. Thus, results from one study of a given product cannot be extrapolated to other products. Despite these limitations, this Clinical Management Review aims to provide practitioners with relevant information on the dosing of selected SLIT formulations in the treatment of allergic respiratory disease.

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

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is in the process of developing Guidelines on Allergen Immunotherapy (AIT) for Allergic Rhinoconjunctivitis. To inform the development of clinical recommendations, we undertook a systematic review to assess the effectiveness, cost-effectiveness, and safety of AIT in the management of allergic rhinoconjunctivitis.

METHODS

We searched nine international biomedical databases for published, in-progress, and unpublished evidence. Studies were independently screened by two reviewers against predefined eligibility criteria and critically appraised using established instruments. Our primary outcomes of interest were symptom, medication, and combined symptom and medication scores. Secondary outcomes of interest included cost-effectiveness and safety. Data were descriptively summarized and then quantitatively synthesized using random-effects meta-analyses.

RESULTS

We identified 5960 studies of which 160 studies satisfied our eligibility criteria. There was a substantial body of evidence demonstrating significant reductions in standardized mean differences (SMD) of symptom (SMD -0.53, 95% CI -0.63, -0.42), medication (SMD -0.37, 95% CI -0.49, -0.26), and combined symptom and medication (SMD -0.49, 95% CI -0.69, -0.30) scores while on treatment that were robust to prespecified sensitivity analyses. There was in comparison a more modest body of evidence on effectiveness post-discontinuation of AIT, suggesting a benefit in relation to symptom scores.

CONCLUSIONS

AIT is effective in improving symptom, medication, and combined symptom and medication scores in patients with allergic rhinoconjunctivitis while on treatment, and there is some evidence suggesting that these benefits are maintained in relation to symptom scores after discontinuation of therapy.

Pooled efficacy and safety data for house dust mite sublingual immunotherapy tablets in adolescents

BACKGROUND

House dust mite (HDM) respiratory allergy is a common and burdensome disease in children and adolescents. There are few HDM allergy immunotherapy trials in children with perennial allergic rhinitis. This post hoc analysis used pooled data to evaluate efficacy and safety of the SQ HDM sublingual immunotherapy (SLIT) tablet in adolescents (12-17 years).

METHODS

In two double-blind, placebo-controlled trials conducted in North America and Japan, respectively, subjects aged 12+ years with HDM allergic rhinitis were randomized to up to 1 year of treatment. The primary end-point in both trials was the average total combined rhinitis score (TCRS) during the last 8 weeks of treatment in the active group compared with placebo. Data from subjects aged 12-17 years were pooled (N=395).

RESULTS

In the pooled adolescent subpopulation, average TCRS improved 22% with 12 SQ HDM vs placebo (absolute treatment difference of 1.04; P<.01). Rhinitis daily symptom score (DSS), conjunctivitis DSS and rhinitis daily medication score (DMS) were also significantly improved vs placebo in the pooled adolescent subpopulation (all P<.05). There were no new safety signals for adolescents. The frequency of adverse events was similar in adolescents and adults with the majority being mild application site-related events.

CONCLUSIONS

Treatment with 12 SQ HDM appears to be effective and well tolerated in adolescents with HDM allergic rhinitis.

House dust mite allergy: Its innate immune response and immunotherapy

Over the past few decades, allergic diseases have become increasingly prevalent worldwide. House dust mite (HDM) is the most important domestic source for allergic diseases such as allergic rhinitis, asthma and atopic dermatitis. Dermatophagoides pteronyssinus (Der p) is the major environmental allergen in southeast Asia because of the humid and warm environment is suitable for its growth. In the recent year, role of HDM allergen in allergic inflammation through innate immune system has been well studied. Toll-like receptors (TLRs), protease-activated receptors (PARs) and DC-SIGN could be activated by different HDM major allergens and proinflammatory cytokines also be upregulated. Treatment efficacy for HDM allergy is unsatisfied to the patients and the medication is limited. Immunotherapy provided an alternative option for treating HDM allergy through targeted to the mechanisms of allergic reaction and represented a long-term symptoms relief. Gene specific immunotherapy was currently being developed and it could decrease allergic inflammation and improve the efficacy of treatment. In this report, we reviewed recent studies about the role of HDM allergy in innate immune system and its immunotherapy. Understanding the HDM allergen induced signal transduction pathway and developed allergen specific immunotherapy could help physicians to create precise diagnosis and solve unmet need in HDM allergy.

Clinical benefits of treatment with SQ house dust mite sublingual tablet in house dust mite allergic rhinitis

Treatment with SQ (standardised quality) house dust mite sublingual tablet for 1 year resulted in a decreased probability of having an allergic rhinitis (AR) exacerbation day (from 11% [placebo] to 5% [SQ house dust mite sublingual tablet]) and an increased probability of having a mild AR day (from 16% [placebo] to 34% [SQ house dust mite sublingual tablet]).

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.

Bioavailability of House Dust Mite Allergens in Sublingual Allergy Tablets Is Highly Dependent on the Formulation

BACKGROUND

In sublingual immunotherapy (SLIT), the immune system is addressed by solubilized allergen that interacts with immunocompetent cells of the oral mucosa, the efficiency of which is governed by 2 main factors of SLIT allergen bioavailability: the allergen concentration and the mucosal contact time. Recently, 3 house dust mite (HDM) SLIT tablets were developed that differ with regard to allergen content, nominal strength (maintenance doses: 6 SQ-HDM/10,000 Japanese Allergen Units [JAU], 12 SQ-HDM/ 20,000 JAU, and 300 IR/57,000 JAU), and formulation (freeze-dried/compressed). Here, the importance of the SLIT tablet formulation for HDM major allergen bioavailability is examined.

METHODS

The HDM major allergen content, tablet disintegration times, and allergen release kinetics were determined. Dissolution kinetics (allergen concentration vs. time) of Der f 1, Der p 1, and Der 2 were measured. Area under the curve (AUC) was used as a surrogate parameter for allergen bioavailability.

RESULTS

The release of HDM major allergens from the freeze-dried tablets was complete after 30 s, while only partial release was achieved with the compressed tablets, even after prolonged dissolution. At 1 min, i.e., the recommended sublingual holding time for the freeze-dried tablets, the allergen bioavailability (AUC) of the compressed 300 IR/57,000 JAU tablet was 4.7-fold (Der f 1), 10.8-fold (Der p 1), and 23.6-fold (Der 2) lower than that of the freeze-dried 12 SQ-HDM/20,000 JAU tablet and similar to (Der f 1) and 5.3-fold (Der p 1) and 12.5-fold (Der 2) lower than that of the freeze-dried 6 SQ-HDM/10,000 JAU tablet.

CONCLUSIONS

SLIT tablet allergen bioavailability depends highly on the tablet formulation. Only the fast-dissolving freeze-dried tablets provide maximal delivery of soluble allergens and achieve allergen concentrations that reflect the nominal tablet strengths within the recommended sublingual holding time.

Advances and highlights in allergen immunotherapy: On the way to sustained clinical and immunologic tolerance

Allergen immunotherapy (AIT) is an effective treatment strategy for allergic diseases and has been used for more than 100 years. In recent years, however, the expectations on concepts, conduct, statistical evaluation, and reporting have developed significantly. Products have undergone dose-response and confirmative studies in adults and children to provide evidence for the optimal dosage, safety, and efficacy of AIT vaccines using subcutaneous and sublingual delivery pathways in large patient cohorts, ensuring solid conclusions to be drawn from them for the advantage of patients and societies alike. Those standards should be followed today, and products answering to them should be preferred over others lacking optimization and proof of efficacy and safety. Molecular and cellular mechanisms of AIT include early mast cell and basophil desensitization effects, regulation of T- and B-cell responses, regulation of IgE and IgG₄ production, and inhibition of responses from eosinophils, mast cells, and basophils in the affected tissues. There were many developments to improve vaccination strategies, demonstration of new molecules involved in molecular mechanisms, and demonstration of new biomarkers for AIT during the last few years. The combination of probiotics, vitamins, and biological agents with AIT is highlighting current advances. Development of allergoids and recombinant and hypoallergenic vaccines to skew the immune response from IgE to IgG₄ and regulation of dendritic cell, mast cell, basophil, innate lymphoid cell, T-cell, and B-cell responses to allergens are also discussed in detail.

Major allergen content consistency of SQ house dust mite sublingual immunotherapy tablets and relevance across geographic regions

BACKGROUND

Consistency in composition and potency, particularly regarding major allergens, is crucial for the quality of extracts for allergen immunotherapy.

OBJECTIVE

To characterize the major allergen composition of house dust mite (HDM) extracts commercially available in the United States and the SQ HDM sublingual immunotherapy (SLIT) tablet, and to relate the composition to patient sensitization patterns.

METHODS

Der 1/Der 2 ratios were determined in 10,000- and 30,000-AU/mL HDM extracts from 5 US companies and the SQ HDM SLIT-tablet. Allergen content was analyzed by enzyme-linked immunosorbent assay and compared with an in-house reference. Sensitivity toward Der p 1, Der p 2, and Der p 10 was determined in serum from randomly selected subgroups of 220 individuals from North American and European SQ HDM SLIT-tablet trials.

RESULTS

Mean Der 1/Der 2 ratios in US HDM extracts ranged from 0.4 to 20.5. For the SQ HDM SLIT-tablet (20 batches), variability did not exceed 12% regarding content of Der f 1 (SD, 11.9%; 95% confidence interval [CI], 0.94-1.06), Der p 1 (SD, 6.1%; 95% CI, 0.97-1.03), and combined Der 2 allergen (SD, 6.4%; 95% CI, 0.97-1.03), indicating a consistent Der 1/Der 2 ratio. High allergen sensitivity frequencies toward Der p 1 and Der p 2 were observed regardless of geographic region. Efficacy of the SQ HDM SLIT-tablet has been demonstrated in 5 clinical trials.

CONCLUSION

The SQ HDM SLIT-tablet has efficacy potential for a broad range of patients because it includes a consistent 1:1 ratio of the 2 major HDM allergens to which individuals were most frequently sensitized across geographic regions. Efficacy has been demonstrated.

Differences and similarities between sublingual immunotherapy of allergy and oral tolerance

Allergen immunotherapy is the only treatment altering the natural course of IgE-mediated allergies. Whereas the subcutaneous route for immunotherapy (SCIT) has been historically considered as a reference, we discuss herein the relative advantages of the sublingual and oral routes as alternatives to SCIT in order to elicit allergen-specific tolerance. The buccal and gut immune systems are similarly organized to favor immune tolerance to antigens/allergens, due to the presence of tolerogenic dendritic cells and macrophages promoting the differentiation of CD4⁺ regulatory T cells. Sublingual immunotherapy (SLIT) is now established as a valid treatment option, with clinical efficacy demonstrated in allergic rhinoconjunctivitis (to either grass, tree, weed pollens or mite allergens) and encouraging results obtained in the management of mild/moderate allergic asthma. While still exploratory, oral immunotherapy (OIT) has shown promising results in the desensitization of patients with food allergies. We review at both biological and clinical levels the perspectives currently pursued for those two mucosal routes.

Long-term effects of a house dust mite sublingual immunotherapy tablet in an environmental exposure chamber trial

BACKGROUND

Treatment with SQ house dust mite (HDM) sublingual immunotherapy (SLIT) tablet is effective for HDM respiratory allergic disease, but data on long-term effects are lacking.

OBJECTIVE

Post hoc analyses were conducted to determine the long-term effect of SQ HDM SLIT-tablet on nasal, ocular, and cough symptoms 1 year after discontinuation of treatment.

METHODS

Study participants underwent environmental exposure chamber (EEC) challenges at baseline and week 24 in a randomized, placebo-controlled, double-blind trial (NCT01644617) during which participants received daily 12 SQ-HDM, 6 SQ-HDM, or placebo for 24 weeks. Asthma had to be stable, well controlled, and nonsevere. The mean total asthma symptom score (TASS; sum of 3 symptoms: cough, wheeze, and dyspnea) during baseline and week 24 EEC challenge was analyzed in all participants who completed the trial (n = 106). Approximately 1 year after trial completion, another EEC challenge was conducted in a subset of participants (n = 51). Total nasal symptom score (sum of 4 symptoms), total ocular symptom score (sum of 2 symptoms), and cough were assessed.

RESULTS

Compared with baseline and end-of-treatment values, sustained improvement of all symptoms assessed at the 1-year follow-up EEC challenge was evident in participants treated with 12 SQ-HDM. Results with 6 SQ-HDM were less notable. After 24 weeks of 12 SQ-HDM, TASS during EEC challenge was improved 65% vs baseline; at 1-year follow-up, cough was improved 57% vs baseline.

CONCLUSION

Persistent improvement of nasal and ocular symptoms was observed up to 1 year after completing 24 weeks of 12 SQ-HDM treatment. Beneficial effects on cough were also observed.

TRIAL REGISTRATION

clinicaltrials.gov Identifier NCT01644617.

Allergen Immunotherapy Clinical Trial Outcomes and Design: Working Toward Harmonization of Methods and Principles

Progress has been made in the harmonization of efficacy and safety outcome measures for allergen immunotherapy (AIT) trials, but unresolved issues still remain. Furthermore, there are discrepancies in recommendations from professional medical societies and regulatory agencies regarding requirements for AIT trials. In this article, we reviewed published recommendations and current data from recent clinical trials, as well as the criteria applied by regulatory authorities for approval of AIT products, to provide updated considerations for conducting phase 3 AIT trials. Topics discussed include analysis of outcomes and trial designs for pediatric and asthma indications, as well as trial designs for perennial allergic rhinoconjunctivitis. In addition, the need for harmonization of safety reporting is emphasized. Considerations presented in this article may further effort to find common ground among professional medical societies and government agencies in developing future recommendations for AIT trial design.

Specific immunotherapy in allergic rhinitis

Allergic rhinitis is a common condition, with significant impact on quality of life depending on severity and quality of control. Allergen-specific immunotherapy (allergen-SIT) is the only known treatment able to alter the natural course of allergic rhinitis. Although well known to allergologists, it has yet to be fully adopted by the ENT community. This review, based on the most recent meta-analyses and clinical studies, shows that SIT significantly reduces symptoms and medication requirements (nasal corticosteroids, H1-antihistamines) in allergic rhinitis. It can reduce the risk of progression to asthma and, if initiated early enough, of developing new sensitizations. Immunobiological analysis shows an altered inflammatory profile following SIT, with immune tolerance involving T-regulatory lymphocyte induction and IgG production. Sublingual SIT with drops is as effective as subcutaneous SIT and is simpler to use, with less anaphylactic risk. Standardization of trial protocols in terms of treatment response assessment and side effect grading is recommended to improve comparative studies. Sublingual SIT with tablets has recently been introduced, providing a good opportunity for ENT practitioners to adopt the SIT approach in rhinitis triggered by allergy to pollens and, in the near future, to house dust mites.

Guideline recommendations on the use of allergen immunotherapy in house dust mite allergy: Time for a change?

Guidelines on the treatment of asthma, allergic rhinitis (AR), and allergen immunotherapy (AIT) lack recommendations for house dust mite (HDM) allergy. An expert panel reviewed current guidelines in the light of new data to assess whether guidelines could be improved. Most guidelines and key position papers did not provide specific recommendations on treatment of allergic asthma (AA) caused by HDM allergy, although some included AIT as a treatment option for AA in general. Around half of the guidelines stated that AIT with HDM extract was an effective treatment for AR, with several indicating sublingual immunotherapy as an option. This heterogeneity is caused by quality issues affecting studies of AIT with perennial allergens in patients with AA and AR, including use of different diagnosis and severity criteria, lack of consistent scoring or grading systems for primary and safety outcomes, and lack of consensus on treatment parameters. There is a need for well-designed clinical trials to serve as a basis for guideline recommendations. Although results from recent studies strengthen the evidence base for the efficacy and safety of sublingual immunotherapy in patients with HDM-induced AA and AR, their effect on subsequent guideline updates will depend on the methodology and evidence model used by each guideline.

International consensus (ICON) on: clinical consequences of mite hypersensitivity, a global problem

Since mite allergens are the most relevant inducers of allergic diseases worldwide, resulting in significant morbidity and increased burden on health services, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), formed by the American Academy of Allergy, Asthma and Immunology (AAAAI), the American College of Allergy, Asthma and Immunology (ACAAI), the European Academy of Allergy and Clinical Immunology (EAACI), and the World Allergy Organization (WAO), has proposed to issue an International Consensus (ICON) on the clinical consequences of mite hypersensitivity. The objectives of this document are to highlight aspects of mite biology that are clinically relevant, to update the current knowledge on mite allergens, routes of sensitization, the genetics of IgE responses to mites, the epidemiologic aspects of mite hypersensitivity, the clinical pictures induced by mites, the diagnosis, specific immunotherapeutic approaches, and prevention.

A practical guide to the sublingual immunotherapy tablet adverse event profile: implications for clinical practice

OBJECTIVES

Treatment with allergy immunotherapy improves allergic rhinoconjunctivitis, but can also improve comorbidities associated with allergic rhinitis such as asthma. Sublingual immunotherapy (SLIT)-tablets are a convenient and efficacious method of allergy immunotherapy. They are self-administered after the first tablet has been provided under medical supervision. Therapy may elicit local reactions or, rarely, systemic allergic reactions. The objective of this report is to inform healthcare practitioners about the safety and tolerability profile of SLIT-tablets and use this information to provide practical guidance that may inform patients regarding potential adverse reactions and how to manage them.

METHODS

Pooled analyses of safety data from completed randomized, multicenter, double-blind, placebo-controlled phase 2 and phase 3 US and EU trials of timothy grass, short ragweed, and SQ house dust mite SLIT-tablets were conducted to characterize safety and tolerability.

RESULTS

SLIT-tablets are generally well tolerated. No life-threatening events, serious systemic allergic reactions, or events that compromised the airway have been reported. The most common treatment-related adverse events (AEs) are oral site reactions, most of which begin on day 1 of treatment, recur for less than 2 weeks, and resolve after approximately 30-60 minutes. Systemic allergic reactions have been managed with conventional pharmacotherapy. Reactions treated with epinephrine are uncommon, but have been reported. Treatment of AEs, treatment discontinuation considerations, and patient FAQs regarding SLIT-tablet safety/tolerability are discussed.

CONCLUSIONS

This report gives healthcare providers valuable information to educate patients regarding what to expect in terms of SLIT-tablet safety and tolerability. Practical guidance is also provided to ensure proper treatment of any adverse reactions.

House dust mite sublingual tablet is effective and safe in patients with allergic rhinitis

BACKGROUND

House dust mite (HDM) is the major indoor allergen for allergic diseases such as allergic rhinitis (AR) and asthma. Although sublingual immunotherapy is a curative treatment for HDM-induced AR, data from large-scale studies are limited. We evaluated the efficacy and safety of HDM tablets in adolescent and adult patients (aged 12-64 years) with HDM-induced AR with or without intermittent asthma.

METHODS

In a double-blind trial in Japan, 968 subjects were randomized 1 : 1 : 1 to 300 index of reactivity (IR), 500 IR, or placebo groups. The primary endpoint was the Average Adjusted Symptom Score (AASS) in the last eight weeks of the 52-week treatment. Secondary endpoints included individual nasal and ocular symptom scores, rescue medication use, and the Japanese Rhinoconjunctivitis Quality of Life Questionnaire (JRQLQ) scores.

RESULTS

The AASS in the last eight weeks of treatment significantly improved in both the 300 IR and the 500 IR groups compared to that in the placebo group (P < 0.001). In the 300 IR group, the onset of action occurred at week 8-10. All four nasal symptoms significantly improved in both active treatment groups; rescue medication use and JRQLQ outcome improved in the 300 IR group. Most adverse events (AEs) were mild, and 16 serious AEs (SAEs) were reported; however, none of them were drug-related.

CONCLUSIONS

One-year treatment with 300 IR and 500 IR HDM tablets was effective without major safety concerns. The recommended therapeutic dose for AR is 300 IR.

Cost-effectiveness of SQ® HDM SLIT-tablet in addition to pharmacotherapy for the treatment of house dust mite allergic rhinitis in Germany

Background

Allergic rhinitis is a global health problem that burdens society due to associated health care costs and its impact on health. Standardized quality (SQ^®) house dust mite (HDM) sublingual immunotherapy (SLIT)-tablet is a sublingually administered allergy immunotherapy tablet for patients with persistent moderate to severe HDM allergic rhinitis despite use of allergy pharmacotherapy.

Objective

To assess the cost-effectiveness of SQ HDM SLIT-tablet in Germany for patients suffering from HDM allergic rhinitis.

Methods

A pharmacoeconomic analysis, based on data collected in a double-blinded, phase III randomized placebo-controlled trial (n=992), was undertaken to compare SQ HDM SLIT-tablet in addition to allergy pharmacotherapy to placebo plus allergy pharmacotherapy. Quality-adjusted life year (QALY) scores and health care resource use data recorded in the trial were applied to each treatment group and extrapolated over a nine-year time horizon. A series of scenarios were used to investigate the impact of changes on long-term patient health for both treatment groups, which was measured by annual changes in QALY scores. Deterministic and probabilistic sensitivity analyses were also performed.

Results

In the base case analysis, compared with allergy pharmacotherapy, SQ HDM SLIT-tablet led to a QALY gain of 0.31 at an incremental cost of €2,276 over the nine-year time horizon, equating to an incremental cost-effectiveness ratio of €7,519. The treatment was cost-effective for all scenarios analyzed; however, results were sensitive to changes in individual parameter values during the deterministic sensitivity analysis.

Conclusion

SQ HDM SLIT-tablet in addition to pharmacotherapy is cost-effective compared with allergy pharmacotherapy plus placebo for the treatment of persistent moderate to severe HDM allergic rhinitis that is not well controlled by allergy pharmacotherapy.

Improvement of Therapeutic Efficacy of Oral Immunotherapy in Combination with Regulatory T Cell-Inducer Kakkonto in a Murine Food Allergy Model

Oral immunotherapy (OIT) has been considered a promising approach for food allergies (FAs). However, the current OIT strategy is limited in terms of the long-term efficacy and safety. We have previously demonstrated that kakkonto, a traditional Japanese herbal medicine, suppresses the occurrence of allergic symptoms in a murine model of ovalbumin (OVA)-induced FA, which is attributed to the induction of the Foxp3⁺ CD4⁺ regulatory T cells. In this study, we established an OIT model using the FA mice with already established allergic symptoms and determined whether kakkonto could improve the efficacy of OIT. The OIT method consisted of initially administrating a very small amount of OVA and slowly increasing the amount. Allergic symptoms decreased in the OIT-treated FA mice. OIT significantly downregulated Th2 immune response-related gene expression in the FA mouse colon, and decreased the level of mouse mast cell protease-1, a marker of mast cell degranulation in the FA mouse plasma. Moreover, the concomitant use of kakkonto significantly enhanced the effectiveness of OIT on the allergic symptoms, and the combination therapy further suppressed the Th2 immune responses and the mast cell degranulation. In addition, OIT significantly increased the population of Foxp3⁺ CD4⁺ regulatory T cells in the FA mouse colon, and this population was further increased by OIT in combination with kakkonto. Furthermore, the combined therapy with kakkonto reduced the expression of RA-degrading enzyme CYP26B1 mRNA in the FA mouse colon. These findings indicated that the combination of OIT with kakkonto represents a promising approach for FA treatment.

Efficacy of Sublingual Immunotherapy for House Dust Mite-Induced Allergic Rhinitis: A Meta-Analysis of Randomized Controlled Trials

Purpose

Allergic rhinitis (AR) has become a global issue for a large part of the general population. Sublingual immunotherapy (SLIT) has been used extensively to treat persistent allergic rhinitis (PAR). Although systematic reviews have confirmed the effectiveness of SLIT for the treatment of AR, a considerable number of studies using extracts of house dust mites (HDMs) for immunotherapy found no consensus on basic treatment parameters and questioned the efficacy of SLIT.

Methods

In this study, we evaluated SLIT for PAR by a meta-analysis of randomized controlled trials (RCTs). Medline, Embase, and Cochrane Library database searches were performed for RCTs on the treatment of PAR by SLIT that assessed clinical outcomes related to efficacy through May 2016. Descriptive and quantitative information was abstracted. An analysis was performed with standardized mean differences (SMDs) under a fixed or random effects model. Subgroup analyses were performed. Heterogeneity was assessed using the I² metric.

Results

In total, 25 studies were eligible for inclusion in the meta-analysis for symptom scores and 15 studies for medication scores. SLIT was significantly different from the controls for symptom scores (SMD=1.23; 95% confidence interval [CI]=1.74 to 0.73; P<0.001). For medication scores, significant differences for SLIT were also observed versus the controls (SMD=-1.39; 95% CI=-1.90 to -0.88; P<0.001).

Conclusions

Our meta-analysis indicates that SLIT provided significant symptom relief and reduced the need for medications in PAR. In this study, significant evidence was obtained despite heterogeneity with regard to the use of mite extract. Specifically, the mite extract used was provided by the patients with PAR. Furthermore, to confirm both the objective outcomes and the effective doses of HDM allergen extracts, experimental data should be obtained from large high-quality population-based studies.

The Potential Role of Allergen Immunotherapy in Stepping Down Asthma Treatment

For patients whose asthma is controlled and who have a low risk for future exacerbations, current guidelines recommend gradually stepping down pharmacotherapy to identify the lowest dose needed to maintain control. This review article will discuss the benefits and risks of step down in asthma management and the different strategies of achieving step down with particular focus on allergen immunotherapy (AIT). A literature search was conducted to identify studies that assessed the effect of AIT on asthma step down and evaluated this and asthma control as one of the outcomes. Six studies were identified: 2 subcutaneous and 4 sublingual AIT studies. Five studies assessed house dust mite-induced asthma, whereas 1 study focused on birch-induced seasonal asthma. Regarding house dust mite-induced asthma, the AIT studies reviewed suggest that individuals with moderate rather than mild asthma are the patients who are more likely to benefit from the addition of AIT for their asthma condition. The potential value of AIT is likely to be in enabling successful step down of the inhaled corticosteroid dose in Global Initiative for Asthma step 3 or 4. It is important to further explore this effect so that affected individuals can benefit from this treatment.

Comparison of scores associating symptoms and rescue medication use for evaluating the efficacy of allergy immunotherapy in seasonal allergic rhinoconjunctivitis: results from five trials

BACKGROUND

Over the past decade, regulatory bodies and scientific societies recommended, as primary efficacy outcome, a score that reflects both symptom severity and use of rescue medication for clinical trials in allergy immunotherapy (AIT).

OBJECTIVE

We sought to compare the results obtained with two subject-specific scores, the Combined Score (CS) and the Adjusted Symptom Score (AdSS), for assessment of AIT in seasonal allergic rhinoconjunctivitis due to birch and grass pollen allergens.

METHODS

CS and AdSS were evaluated in subjects receiving a 300IR dose of allergen extract daily, by sublingual route, in four clinical trials with the 5-grass pollen tablet (NCT00367640, NCT00409409, NCT00955825 and NCT00418379) and one with the birch pollen solution (NCT01731249). The CS is derived from the Rhinoconjunctivitis Total Symptom Score (RTSS) and the Rescue Medication Score (RMS) giving equal weight to symptoms and medication use. The AdSS is a symptom score adjusting for rescue medication use. Efficacy end-points were analysed using an analysis of covariance linear model.

RESULTS

In all trials, despite the different constructs of the two scores, Combined Score or Adjusted Symptom Score were similarly reduced in the 300IR group compared to the placebo group. Treatment effect was consistently demonstrated with both scores, CS and AdSS, used as either daily scores or average of the daily scores over the pollen season. Minor differences with the same statistical conclusions were observed between the results, leading to the same interpretation.

CONCLUSIONS AND CLINICAL RELEVANCE

The two scores, combined and adjusted scores, for evaluation of clinical efficacy of AIT have led to similar results, with similar statistical conclusions and similar interpretation.

Epinephrine Use in Clinical Trials of Sublingual Immunotherapy Tablets

BACKGROUND

Allergy immunotherapy can result in systemic allergic reactions and even life-threatening anaphylaxis requiring epinephrine administration.

OBJECTIVE

The objective of this study was to describe epinephrine use in the clinical trial development programs of 3 rapidly dissolving sublingual immunotherapy tablets (SLIT-tablets; Merck & Co., Inc., Kenilworth, NJ/ALK, Hørsholm, Denmark/Torii Pharmaceutical Co., Ltd., Tokyo, Japan).

METHODS

Data on epinephrine use were collected from 13 timothy grass SLIT-tablet trials (MK-7243; ≤2800 bioequivalent allergen units/75,000 SQ-T dose, n = 2497; placebo, n = 2139), 5 short ragweed SLIT-tablet trials (MK-3641; ≤12 Amb a 1-U, n = 1725; placebo, n = 770), and 11 house dust mite (HDM) SLIT-tablet trials (MK-8237; ≤12 SQ-HDM; n = 3930; placebo, n = 2246).

RESULTS

In grass SLIT-tablet trials, epinephrine was used 13 times (grass SLIT-tablet, n = 10; placebo, n = 3). Eight administrations were for grass SLIT-tablet-related adverse events (AEs): 4 for systemic allergic reactions and 4 for local mouth and/or throat swelling. In ragweed SLIT-tablet trials, epinephrine was used 9 times in 8 subjects (ragweed SLIT-tablet, n = 7; placebo, n = 1 [2 administrations for protracted anaphylaxis]). Four administrations were for ragweed SLIT-tablet-related AEs: 1 for systemic allergic reaction and 3 for local mouth and/or pharynx/throat swelling. In HDM SLIT-tablet trials, epinephrine was administered 13 times (HDM SLIT-tablet, n = 8; placebo, n = 5). Four administrations were for HDM SLIT-tablet-related AEs: 1 for systemic allergic reaction and 3 for local events. Of the 16 epinephrine administrations for events related to SLIT-tablet treatment, 11 occurred within the first week of treatment (7 administrations on day 1) and 5 were subject self-administered.

CONCLUSIONS

Epinephrine administrations in response to SLIT-tablet-related reactions in clinical trials are uncommon, typically occur within the first week of treatment, and are rarely self-administered. All SLIT-tablet-related events treated with epinephrine were nonserious.

300 IR HDM tablet: a sublingual immunotherapy tablet for the treatment of house dust mite-associated allergic rhinitis

INTRODUCTION

The once-daily 300 index of reactivity (IR) house dust mite (HDM) tablet (Actair®; Stallergenes Greer, Antony, France/Shionogi & Co. Ltd., Osaka, Japan) is the first sublingual immunotherapy (SLIT) tablet to be approved for the treatment of HDM-induced allergic rhinitis. Areas covered: This drug profile reviews the current body of evidence on the efficacy, safety and tolerability of the 300 IR HDM tablet, its pharmacodynamics, and its role in clinical practice. Expert commentary: Data from its clinical development program demonstrate favorable efficacy and safety in adults and adolescents with HDM-induced allergic rhinitis, irrespective of mono- or polysensitization status, or the presence of comorbid mild asthma. The 300 IR HDM tablet is effective from as early as 2 months after treatment initiation, providing allergic symptom control and a reduction in the need for symptomatic medication, while improving health-related quality of life. Clinical efficacy is maintained for 1 year after treatment is stopped.

Efficacy of house dust mite sublingual immunotherapy tablet in North American adolescents and adults in a randomized, placebo-controlled trial

BACKGROUND

The house dust mite (HDM) sublingual immunotherapy (SLIT) tablet (MK-8237; Merck & Co, Kenilworth, NJ/ALK-Abelló, Hørsholm, Denmark) has demonstrated beneficial effects on allergic rhinoconjunctivitis and asthma outcomes in European trials.

OBJECTIVE

This is the first trial to assess the efficacy/safety of HDM SLIT-tablets in North American subjects with HDM-induced allergic rhinitis with or without conjunctivitis (AR/C).

METHODS

In this double-blind, multicenter trial (NCT01700192) 1482 subjects (aged ≥12 years) with HDM-induced AR/C with or without asthma were randomized to a daily SQ HDM SLIT-tablet (12 SQ-HDM dose) or placebo for up to approximately 52 weeks. A rhinitis daily symptom score (DSS; 4 nasal symptoms, maximum score = 12) of 6 or greater, or 5 or greater with 1 symptom being severe, on 5 of 7 consecutive days before randomization was required. The primary end point was the average total combined rhinitis score, which was defined as the rhinitis DSS plus rhinitis daily medication score (DMS), during the last 8 treatment weeks.

RESULTS

Treatment with 12 SQ-HDM improved the total combined rhinitis score by 17% (95% CI, 10% to 25%) versus placebo. Improvements versus placebo in the secondary end points of average rhinitis DSS, rhinitis DMS, total combined rhinoconjunctivitis score, and visual analog scale-assessed AR/C symptoms were 16%, 18%, 17%, and 16%, respectively. All nominal P values were less than .001 versus placebo, except rhinitis DMS (P = 0.15). No treatment-related adverse events meeting the International Council on Harmonization definition of a serious adverse event were reported; 1 nonserious treatment-related systemic allergic reaction occurred (assessed as moderate intensity) at first administration under medical supervision and was treated with epinephrine.

CONCLUSIONS

In the first North American trial of use of a SLIT-tablet for HDM allergy, 12 SQ-HDM was well tolerated and improved HDM-induced rhinitis symptoms in adults and adolescents.

Treatment effect of sublingual immunotherapy tablets and pharmacotherapies for seasonal and perennial allergic rhinitis: Pooled analyses

BACKGROUND

Data comparing the treatment effect of allergy immunotherapy and pharmacotherapy are lacking.

OBJECTIVE

We sought to indirectly compare the treatment effect of sublingual immunotherapy (SLIT)-tablets with pharmacotherapy for seasonal allergic rhinitis (SAR) and perennial allergic rhinitis (PAR).

METHODS

Pooled data from randomized, double-blind, placebo-controlled trials for the clinical development programs of selected allergic rhinitis treatments were evaluated. Total nasal symptom scores (TNSSs) relative to placebo were compared. Subjects scored symptoms daily during entire pollen seasons in 6 timothy grass SLIT-tablet trials (n = 3094) and 2 ragweed SLIT-tablet trials (n = 658) and during the last 8 weeks of treatment in 2 house dust mite (HDM) SLIT-tablet trials (n = 1768). Subjects scored symptoms daily in 7 montelukast (10 mg, n = 6799), 9 desloratadine (5 mg, n = 4455), and 8 mometasone furoate nasal spray (MFNS; 200 μg daily, n = 2140) SAR or PAR trials. SLIT-tablet trials allowed rescue medication use, whereas most pharmacotherapy trials did not. A fixed-effect meta-analysis method estimated differences in on-treatment average TNSSs.

RESULTS

In grass and ragweed SLIT-tablet trials, overall improvement in TNSSs relative to placebo was 16.3% and 17.1%, respectively. In HDM SLIT-tablet trials, TNSS overall improvement relative to placebo was 16.1%. In the montelukast, desloratadine, and MFNS trials, TNSS overall improvement relative to placebo was 5.4%, 8.5%, and 22.2%, respectively, for SAR trials, and 3.7%, 4.8%, and 11.2%, respectively, for PAR trials.

CONCLUSIONS

Although comparisons were limited by study design heterogeneity and use of rescue medications in SLIT-tablet trials, effects on nasal symptoms with timothy grass and ragweed SLIT-tablets were nearly as great as with MFNS and numerically greater than with montelukast and desloratadine for SAR. HDM SLIT-tablet effects were numerically greater than all pharmacotherapies for PAR. SLIT-tablets offer the additional benefit of long-term efficacy.

Efficacy and safety of SQ house dust mite (HDM) SLIT-tablet treatment of HDM allergic asthma

INTRODUCTION

In the treatment of house dust mite (HDM) respiratory allergic disease, allergy immunotherapy constitutes an add-on treatment option targeting the underlying immunological mechanisms of allergic disease. However, for the treatment of HDM allergic asthma, the use of subcutaneous allergy immunotherapy (SCIT) has been limited by the risk of systemic adverse events. Thus, sublingually administered allergy immunotherapy (SLIT) has been investigated as a treatment option with an improved tolerability profile that allows for safer treatment of patients with HDM allergic asthma.

AREAS COVERED

In this Drug Profile, we provide a review of the clinical data behind the SQ HDM SLIT-tablet, which was recently approved for the treatment of HDM allergic asthma and allergic rhinitis by regulatory authorities in several European countries. Expert commentary: The SQ HDM SLIT-tablet is the first allergy immunotherapy to be tested prospectively in patients with asthma, and to favorably modify patient relevant end points such as requirement for inhaled corticosteroid (ICS) or the time to first asthma exacerbation upon ICS reduction, suggesting that SQ HDM SLIT-tablet treatment may contribute to improving overall asthma control.

New opportunities for allergen immunotherapy using synthetic peptide immuno-regulatory epitopes (SPIREs)

INTRODUCTION

Allergen immunotherapy (AIT) reduces allergic rhinoconjunctivitis (ARC) symptoms, but long-term efficacy requires treatment for 3-5 years. Synthetic peptide immuno-regulatory epitopes, a new class of AIT, are allergen peptides with a shorter, more convenient treatment regimen that could potentially have benefits on adherence and outcomes.

AREAS COVERED

Phase 2 trials of therapies derived from cat, house dust mite, grass, and ragweed allergen peptides demonstrated significant reduction in ARC symptoms after short-course treatment; improvement was sustained for 18-24 months posttreatment. We conducted a PubMed literature search for clinical publications using the search terms AIT; allergen peptides; ARC; cat, grass, house dust mite, and ragweed allergy; SCIT; SLIT; and synthetic peptides. Expert commentary: Long-term disease modification is a realistic goal of AIT. The inconvenience of conventional AIT regimens negatively impacts long-term persistence and, thus, efficacy. In comparison, SPIREs have a more convenient treatment regimen that could potentially have benefits on adherence and outcomes.

House Dust Mite-Specific Sublingual Immunotherapy Prevents the Development of Allergic Inflammation in a Mouse Model of Experimental Asthma

BACKGROUND

Evidence regarding sublingual immunotherapy (SLIT) efficacy and its good safety profile has been demonstrated with pollen and house dust mite (HDM) allergens in the treatment of airway allergies. In addition, the use of grass pollen presents a SLIT disease-modifying treatment for respiratory allergies.

OBJECTIVES

The aim of this study was to demonstrate the efficacy of HDM-based SLIT in mouse models of allergic airway inflammation and to gain insights into the involved local immunological mechanisms.

METHODS

Balb/c mice were sensitized/challenged with Dermatophagoides farinae (Der f) extract and underwent Der f-SLIT in prophylactic and therapeutic settings. The SLIT efficacy was assessed using lung function measurements, analysis of local inflammatory responses by bronchoalveolar lavage cell differentiation and lung histology. Humoral and cellular responses were monitored by ELISA, cytokine bead array and flow cytometry analyses.

RESULTS

In a prophylactic setting, Der f-SLIT with 12 development units per dose reduced the eosinophil-dominated inflammatory response in the lung paralleled by a marked reduction in airway hyperresponsiveness. Local Th2 responses were prevented as demonstrated by significantly lower levels of IL-5 and IL-13. Additionally, SLIT-treated mice revealed a lower proportion of CD4-CD8- x03B3;δ cells and a higher frequency of CD8+CD25+IFNx03B3;+ T cells in the lungs compared to sham-treated mice. In a therapeutic setting, Der f-SLIT also resulted in reduced inflammatory responses in the lung.

CONCLUSION

The efficacy of Der f-SLIT was demonstrated in prophylactic and therapeutic conditions using experimental mouse models of HDM-induced airway inflammation. A potential role of a so far underestimated lymphocyte subpopulation was also indicated.