Sublingual immunotherapy in patients with allergic rhinoconjunctivitis caused by ragweed pollen

[Allergen immunotherapy for rare allergens]

Among allergies to aeroallergens, approximately 20% are allotted to the so-called rare allergens. These include ash pollen, weed pollen, storage mites, molds, and animal allergens. The prevalences of allergies to these allergens are lower, but affected patients also suffer considerably from their "rare" allergy. Hence, these allergies should neither be overseen nor completely forgotten in daily practice. Especially mold, mite, and animal allergens often induce asthma, so that the significance of allergen-specific immunotherapy (AIT) should not be neglected in causal therapy. This work summarizes the current state of knowledge on the groups of rare aeroallergens in terms of characteristics, prevalences, and data on AIT. It is based on a systematic literature search performed in the MEDLINE (PubMed®) and Google Scholar databases. AIT preparations for rare allergens are classified as individual formulations and are not subject to the German Therapy Allergen Ordinance. Due to the low case numbers, the levels of evidence for these formulations are not as high as those for dust mites, grass, or birch pollen, but exhibit good efficacy in practical experience.

The Art of Immunotherapy

Selection of a patient with rhinitis/conjunctivitis or asthma for allergy immunotherapy (AIT) requires several decisions. First, does the patient's sensitization, pattern of exposure to an allergen, and degree of exposure to that allergen reasonably suggest a causal relationship? Does the level and duration of symptoms warrant the cost and inconvenience of immunotherapy, or is the patient motivated by the disease-modifying potential of AIT? If AIT is selected, is the choice to be greater safety and convenience with sublingual immunotherapy (SLIT) tablets, but with treatment probably limited to 2 or 3 allergens, or for subcutaneous immunotherapy where multiple allergen therapy is the rule and efficacy may be somewhat greater, at least initially, or does the physician go off-label into the unknowns of liquid SLIT? Are there extracts of sufficient potency to achieve likely effective doses? How does the physician deal with large local or systemic reactions, with gaps in treatment, with pollen seasons, and the use of premedication or cautionary prescription of epinephrine autoinjectors? How can adherence to AIT be improved? These and other questions are addressed in this paper.

Short-course subcutaneous treatment with PQ Grass strongly improves symptom and medication scores in grass allergy

BACKGROUND

A modified grass allergen subcutaneous immunotherapy (SCIT) product with MicroCrystalline Tyrosine and monophosphoryl lipid-A as an adjuvant system (Grass MATA MPL [PQ Grass]) is being developed as short-course treatment of grass-pollen allergic rhinitis (SAR) and/or rhinoconjunctivitis. We sought to evaluate the combined symptom and medication score (CSMS) of the optimized cumulative dose of 27,600 standardized units (SU) PQ Grass in a field setting prior to embarking on a pivotal Phase III trial.

METHODS

In this exploratory, randomized, double-blind, placebo-controlled trial subjects were enrolled across 14 sites (Germany and the United States of America). Six pre-seasonal subcutaneous injections of PQ Grass (using conventional or extended regimens) or placebo were administered to 119 subjects (aged 18-65 years) with moderate-to-severe SAR with or without asthma that was well-controlled. The primary efficacy endpoint was CSMS during peak grass pollen season (GPS). Secondary endpoints included Rhinoconjunctivitis Quality of Life Questionnaire standardized (RQLQ-S) and allergen-specific IgG4 response.

RESULTS

The mean CSMS compared to placebo was 33.1% (p = .0325) and 39.5% (p = .0112) for the conventional and extended regimens, respectively. An increase in IgG4 was shown for both regimens (p < .01) as well as an improvement in total RQLQ-S for the extended regimen (mean change -0.72, p = .02). Both regimens were well-tolerated.

CONCLUSIONS

This trial demonstrated a clinically relevant and statistically significant efficacy response to PQ Grass. Unprecedented effect sizes were reached for grass allergy of up to ≈40% compared to placebo for CSMS after only six PQ Grass injections. Both PQ Grass regimens were considered equally safe and well-tolerated. Based on enhanced efficacy profile extended regime will be progressed to the pivotal Phase III trial.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Delivery options for sublingual immunotherapy for allergic rhinoconjunctivitis: clinical considerations for North America

Background: Sublingual immunotherapy (SLIT) can be delivered via tablets (SLIT-T) or aqueous drops (SLIT-D). SLIT-D dosing recommendations using North American extracts were published in 2015. We review the 2015 recommendations in the context of recent research, and compare and contrast dosing, efficacy, safety, adherence, and cost of SLIT-T and SLIT-D for allergic rhinoconjunctivitis (ARC) in North America. Methods: Randomized controlled trials (RCT) of SLIT-D and SLIT-T trials were identified by a systematic PubMed search through March 1, 2022. Results: Dose-finding studies have been conducted for all approved SLIT-T; efficacy in North American populations was demonstrated in 11 RCTs. Approved SLIT-T are uniform internationally. Few dose-finding studies for SLIT-D have been conducted using North American extracts; efficacy was demonstrated in 2 RCTs. Extrapolation of dosing from SLIT-D studies conducted with extracts from other geographic regions is unreliable. Since the 2015 SLIT-D dosing recommendations, no new RCTs of SLIT-D have been conducted with North American extracts, whereas 6 SLIT-T RCTs have since been conducted in North America. Local allergic reactions are the most common adverse events with SLIT-T and SLIT-D, but both can induce systemic allergic reactions. Adherence to SLIT-D and SLIT-T remains a challenge. Patients must pay for SLIT-D directly, whereas SLIT-T is usually covered by insurance. Conclusion: As part of shared decision-making, patients should be informed about the scientific evidence supporting the use of SLIT-T and SLIT-D for ARC.

Ragweed sublingual immunotherapy (SLIT) tablets in allergic rhinoconjunctivitis: a systematic review and meta-analysis

PURPOSE

Ragweed allergen causes Allergic rhinoconjunctivitis and sublingual immunotherapy is one of the treatment modalities to desensitize allergic individuals. This systematic review assesses the effectiveness and safety of sublingual immunotherapy for allergic rhinoconjunctivitis caused due to Ragweed.

METHODS

The databases search was done through December 2020. English-language randomized controlled trials were included if they compared sublingual immunotherapy with placebo, pharmacotherapy, or other sublingual immunotherapy regimens, and reported clinical outcomes. The strength of the evidence for each comparison and outcome was graded based on the risk of bias, consistency, magnitude of effect, and the directness of the evidence.

RESULTS

The searches performed according to the protocol identified 134 abstracts of which 67 were duplicates. A total of 37 full papers were therefore reviewed of which 5 were included for the final study. Participants' ages ranged from 4 to 58 years. The risk of bias was low in most studies. The review suggests that sublingual immunotherapy improves rhinoconjunctivitis symptoms, with 4 of 4 studies reporting efficacy showed improvement in the symptom score of SLIT groups compared to placebo. Local reactions were frequent, but anaphylaxis was not reported in any of the studies. Serious adverse events were very few in all the studies.

CONCLUSIONS

The overall evidence showed the effectiveness of sublingual immunotherapy for the treatment of allergic rhinoconjunctivitis with or without asthma, but high-quality studies are still needed to answer questions regarding optimal dosing strategies.

How important is proper dosing for subcutaneous and sublingual allergy immunotherapy?

Background: Results of surveys report that allergists use a wide range of doses for allergy immunotherapy; however, results of randomized, double-blind, placebo controlled studies suggest that the range of the optimum effective dosing is relatively narrow. Objective: To review studies that established effective or less than fully effective doses for allergy immunotherapy. Methods: Studies were reviewed that established effective and ineffective subcutaneous and sublingual immunotherapy doses. Only those studies that expressed dosing in terms of the content of a major allergen in the maintenance doses were included in defining effective and ineffective doses. Results: Studies were identified that showed effective doses for subcutaneous injection, established in randomized, double-blind, placebo controlled trials, for short ragweed, timothy grass, house-dust mites, cat and dog dander, birch, and Alternaria. For short ragweed, timothy grass, Dermatophagoides pteronyssinus, and cat and dog dander, less-effective doses were determined, along with effective doses; the less-effective doses were only one-fifth to one-tenth less in allergen content than were the effective doses. Effective doses of cockroach and all fungal extracts except Alternaria have not been established. Information is available on the mean major allergen content of U.S. standardized and a few nonstandardized extracts, which allows the information on effective and ineffective dosing to be used in prescribing subcutaneous allergy immunotherapy. With sublingual allergy immunotherapy, all the approved tablets had multidose studies that determined the optimal dose. For the U.S. liquid extracts, to my knowledge, there are no studies to define effective doses except for ragweed. Conclusions: Although a wide range of doses are prescribed by U.S. allergists, analysis of available data suggests that effective doses fall within a narrow range and that use of doses one-fifth or one-tenth of the effective doses may sacrifice most or all of the potential efficacy of the treatment.

Subcutaneous Versus Sublingual Immunotherapy for Adults with Allergic Rhinitis: A Systematic Review with Meta-Analyses

OBJECTIVES

To determine whether subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT) better improves patient outcomes and quality of life for adults with allergic rhinitis or rhinoconjunctivitis (AR/C) with or without mild to moderate asthma.

METHODS

Systematic review methodology was based on the Cochrane Collaboration handbook and Preferred Reporting Items for Systematic Reviews and Meta-analyses. Four databases (PubMed, Cochrane Library, EMBASE, and Web of Science) were queried from inception to July 30, 2020. Two independent reviewers screened potentially relevant studies and assessed risk of bias. Outcomes of interest were symptom score (SS), medication score (MS), combined symptom medication score (CSMS), and Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ). Meta-analyses with an adjusted indirect comparison were conducted in RevMan 5.4.1.

RESULTS

Seven SCIT versus SLIT randomized controlled trials (RCTs) demonstrated no significant differences for any outcomes, but insufficient data precluded direct meta-analysis. For the adjusted indirect comparison, 46 RCTs over 39 studies were included for SCIT versus placebo (n = 13) and SLIT versus placebo (n = 33). Statistically significant results favoring SCIT were found for SS (standardized mean difference [SMD] = 0.40; 95% confidence interval [CI] = 0.31-0.49), MS (SMD = 0.26; 95% CI = 0.14-0.39), CSMS (SMD = 0.42; 95% CI = 0.17-0.67), and RQLQ (MD = 0.24; 95% CI = 0.04-0.44). Statistically significant results favoring SLIT were found for SS (SMD = 0.42; 95% CI = 0.32-0.53), MS (SMD = 0.40; 95% CI = 0.28-0.53), CSMS (SMD = 0.37; 95% CI = 0.29-0.45), and RQLQ (MD = 0.32; 95% CI = 0.20-0.43). No significant differences were found between SCIT and SLIT for SS (SMD = -0.02; 95% CI = -0.15 to 0.11), MS (SMD = -0.14; 95% CI = -0.31 to 0.03), CSMS (SMD = 0.05; 95% CI = -0.21 to 0.31), or RQLQ (MD = -0.08; 95% CI = -0.31 to 0.15).

CONCLUSION

SCIT and SLIT are comparably effective treatments for adults with AR/C. More RCTs analyzing SCIT versus SLIT are needed to directly compare the two. Laryngoscope, 2021.

Clinical aspects of sublingual immunotherapy tablets and drops

BACKGROUND

Sublingual immunotherapy (SLIT) is administered via tablets (SLIT-T) or liquid drops (SLIT-D). In North America, currently 4 SLIT-T formulations are approved by the US Food and Drug Administration for allergy immunotherapy, and SLIT-D is an off-label use of subcutaneous immunotherapy (SCIT) extracts.

OBJECTIVE

To compare and contrast aspects of SLIT-T and SLIT-D, including physical characteristics, mechanism of action, dosing, efficacy, safety, adherence, and cost.

DATA SOURCES

PubMed literature review (no limits), product prescribing information, and manufacturer websites.

STUDY SELECTIONS

Publications related to physical characteristics, mechanism of action, dosing, efficacy, safety, and adherence.

RESULTS

Published evidence indicates that tablet and drop formulations differ in regard to physical characteristics, dosing, and strength of evidence for efficacy. Whether there are any differences in absorption and mechanism of action between the 2 formulations is currently unknown. Optimal dosing, efficacy, and safety have been established for SLIT-T. In contrast, in North America there is little support for efficacy of SLIT-D from randomized double-blind, placebo-controlled trials, and dose ranges have not been appropriately evaluated. SLIT-T treats a single allergen, whereas in the United States SLIT-D often contains multiple allergens to treat polysensitization. The safety profiles of SLIT-T and SLIT-D appear similar, and both formulations are considered safer than SCIT.

CONCLUSION

Professional guidelines should make a clear distinction between SLIT-T and SLIT-D in their recommendations to minimize confusion with the umbrella term SLIT.

Sublingual allergen immunotherapy for respiratory allergy: a systematic review

The objective of the systematic review is to provide complete and updated information on efficacy and safety of sublingual immunotherapy (SLIT) formulations for the treatment of allergic respiratory diseases (ARDs). The literature search was conducted on PubMed database, involving double-blind, randomized clinical trials published between January 1992 and 2018, written in English, and performed in humans. The number of articles finally selected for review was 112. Data from the majority of properly controlled clinical trials demonstrate that SLIT is effective not only with short-term use (first year) but also with long-term use (up to the third year of active therapy), for treating ARDs in children and adults. Both continuous and discontinuous schemes of administration showed significant reductions in symptom and medication scores. Moreover, a SLIT-induced disease-modifying effect has been documented mainly with grass pollen extracts, since improvement is maintained during at least 2 years of follow-up after a 3-year treatment period. Additionally, allergen immunotherapy should also be considered a preventive strategy, especially for decreasing bronchial asthma incidence in children and adolescents with allergic rhinitis treated with SLIT. This therapy is also safe, producing only a few mainly local and mild-to-moderate adverse events, and usually self-limited in time. The registration and authorization of allergen SLIT preparations (grasses and house-dust mite tablets) as drugs by regulatory agencies, such as the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA), has represented a landmark in allergy immunotherapy research. Further long-term studies, specially designed with allergens other than grass pollen or house-dust mites, not only in allergic rhinoconjunctivitis but also on asthmatic subjects, as well as studies comparing different administration schedules and/or routes, are required in order to continue the progress in the modern development of this particularly promising therapy.

Ragweed allergy immunotherapy tablet MK-3641 (Ragwitek®) for the treatment of allergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is among the most common chronic conditions affecting both children and adults. It is the cause of significant morbidity from the symptoms and interference with sleep. It results in major impairment of performance both at school and at work. In the U.S. and certain parts of Europe, ragweed pollen is a major cause of seasonal AR. In 2014, the U.S. Food and Drug Administration (FDA) approved a sublingual ragweed tablet (MK-3641) for use in adults with ragweed-induced AR. Areas covered: This paper will review the impact of ragweed-induced AR and available treatments including subcutaneous immunotherapy and studies with MK-3641. The principal search method was PubMed. Expert commentary: One dosing finding, two 28-day safety and two 52-week safety and efficacy studies have been conducted with MK-3641. The 12-U (12μg Amb a 1) tablet was the most effective. Local application site reactions were common but usually not serious. Only one, non-serious systemic reaction was reported in four safety studies. MK-3641 is a safe and effective treatment for ragweed-pollen-induced AR when treatment is initiated ≥ 12 weeks prior to the onset of the ragweed pollen season.

Randomized controlled trials define shape of dose response for Pollinex Quattro Birch allergoid immunotherapy

BACKGROUND

The Birch Allergoid, Tyrosine Adsorbate, Monophosphoryl Lipid A (POLLINEX^® Quattro Plus 1.0 ml Birch 100%) is an effective, well-tolerated short course subcutaneous immunotherapy. We performed 2 phase II studies to determine its optimal cumulative dose.

METHODS

The studies were conducted in Germany, Austria and Poland (EudraCT numbers: 2012-004336-28 PQBirch203 and 2015-000984-15 PQBirch204) using a wide range of cumulative doses. In both studies, subjects were administered 6 therapy injections weekly outside the pollen season. Conjunctival Provocation Tests were performed at screening, baseline and 3-4 weeks after completing treatment, to quantify the reduction in Total Symptom Scores (as the primary endpoint) with each cumulative dose. Multiple Comparison Procedure and Modeling analysis was used to test for the dose response, shape of the curve and estimation of the median effective dose (ED₅₀ ), a measure of potency.

RESULTS

Statistically significant dose responses (P < .01 & .001) were seen, respectively. The highest cumulative dose in PQBirch204 (27 300 standardized units [SU]) approached a plateau. Potency of the PQBirch was demonstrated by an ED₅₀ 2723 SU, just over half the current dose. Prevalence of treatment-emergent adverse events was similar for active doses, most being short-lived and mild. Compliance was over 85% in all groups.

CONCLUSION

Increasing the cumulative dose of PQBirch 5.5-fold from 5100 to 27 300 SU achieved an absolute point difference from placebo of 1.91, a relative difference 32.3% and an increase in efficacy of 50%, without compromising safety. The cumulative dose response was confirmed to be curvilinear in shape.

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.

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.

Sublingual immunotherapy tablets as a disease-modifying add-on treatment option to pharmacotherapy for allergic rhinitis and asthma

Allergic rhinitis (AR) with or without conjunctivitis (AR/C) is associated with a significant health and economic burden, and is often accompanied by asthma. Pharmacotherapies are the mainstay treatment options for AR and asthma, but guidelines also recommend allergy immunotherapy (AIT). Unlike pharmacotherapies, AIT has the ability to modify the underlying immunologic mechanisms of AR and asthma with the potential for long-term benefits after treatment is discontinued. Immunotherapy may also prevent progression of AR/C to asthma. Sublingual immunotherapy (SLIT)-tablets are a self-administered alternative to subcutaneous immunotherapy that provide the benefits of AIT without the cost and inconvenience of frequent office visits or the discomfort of injections. SLIT-tablets are also an option that can be utilized by primary care clinicians. Pharmacotherapies are generally effective in mild disease although a number of patients remain uncontrolled. SLIT-tablets have proven efficacy for AR in adults, children, and poly-sensitized allergic patients. Indirect comparisons indicate that SLIT-tablets have superior or comparable efficacy compared with traditional pharmacotherapies for seasonal AR, and superior efficacy for perennial AR. House dust mite (HDM) SLIT-tablets have also demonstrated clinically relevant benefits for asthma, with significant observed reductions in daily inhaled corticosteroid use, risk of asthma exacerbations, and asthma symptoms. SLIT-tablets are well tolerated, with minimal risk of systemic allergic reactions. The most common treatment-related adverse events are oral site reactions such as oral pruritus and throat irritation. Based on the favorable efficacy and safety profile, as well as the convenience of at-home oral administration and disease-modifying effects, SLIT-tablets should be considered as an alternative or add-on treatment to pharmacotherapy for AR/C, and as an add-on treatment for HDM allergic asthma.

Current Evidence on Safety and Practical Considerations for Administration of Sublingual Allergen Immunotherapy (SLIT) in the United States

Liquid sublingual allergen immunotherapy (SLIT) has been used off-label for decades, and Food and Drug Administration (FDA)-approved grass and ragweed SLIT tablets have been available in the United States since 2014. Potentially life-threatening events from SLIT do occur, although they appear to be very rare, especially for FDA-approved products. Practice guidelines that incorporate safety precautions regarding the use of SLIT in the United States are needed. This clinical commentary attempts to address unresolved issues including controversy regarding the FDA mandate for the prescription of epinephrine autoinjectors for patients on SLIT; how to approach polysensitized patients; optimal timing and duration of SLIT administration; how to address gaps in therapy; whether antihistamines can prevent local reactions, if certain patient populations (such as persistent asthmatics) should not receive SLIT; and when to instruct patients to self-administer epinephrine. Key points are that physicians should focus on educating patients regarding: (1) when not to administer SLIT; (2) how to recognize a potentially serious allergic reaction to SLIT; and (3) when to administer epinephrine and seek emergency care.

Subcutaneous Immunotherapy and Sublingual Immunotherapy: Comparative Efficacy, Current and Potential Indications, and Warnings--United States Versus Europe

Subcutaneous immunotherapy and sublingual immunotherapy are effective for allergic rhinitis and allergic asthma and with some support for use in selected patients with atopic dermatitis. The sequence of immunologic responses is the same, irrespective of the route of administration, and similar disease modification has been demonstrated. However, there are differences between the two approaches. The most important is the greatly reduced likelihood of sublingual immunotherapy producing systemic reactions. There are major drawbacks for sublingual immunotherapy in regard to dosing. Finally, there is the question of relative clinical efficacy, with the currently available data favoring subcutaneous immunotherapy.

The efficacy assessment of a self-administered immunotherapy protocol

Background

We previously reported the safety of a self‐administered subcutaneous immunotherapy (SCIT) protocol. Here we report the results of the retrospective efficacy trial of the United Allergy Service (UAS) self‐administered SCIT protocol. We hypothesized that by utilizing a slow SCIT buildup phase, designed to attain recommended allergen concentrations on a cumulative basis, efficacious outcomes and clinical relevance would be achieved.

Methods

We enrolled 60 SCIT patients and 56 control patients. The study contrasted baseline and treatment period combined symptom plus medication scores (CSMS) as the primary outcome measure and rhinoconjunctivitis quality of life questionnaire (RQLQ) scores as the secondary study outcome measure. Changes in pollen counts were also examined with regard to effects on these efficacy parameters.

Results

The treatment group showed significantly improved CSMS (standardized mean difference [SMD]: −1.57; 95% confidence interval [CI], −1.97 to −1.18; p < 0.001) and RQLQ (SMD: −0.91; 95% CI, −1.23 to −0.59; p < 0.001). These treatment group outcome measures were respectively improved by 33% and 29% compared to baseline and greater than 40% in comparison to the control group (p < 0.0001). Significant results were also shown when examining these outcome measures with regards to either monotherapy or poly‐allergen SCIT. Furthermore, a comparison to recent meta‐analyses of SCIT studies showed equivalent efficacy and clinical relevance. Assessment of pollen counts during the baseline and treatment periods further corroborated the efficacy of the UAS SCIT protocol.

Conclusion

These efficacy results, and our previous safety results, show that a carefully designed and implemented self‐administered SCIT protocol is efficacious and safe.

Dosing of sublingual immunotherapy for allergic rhinitis: evidence-based review with recommendations

BACKGROUND

Since the mid 1980s, the clinical use of sublingual immunotherapy (SLIT) has dramatically increased. However, 1 of the primary barriers to providing SLIT is lack of a published dosing recommendations. The purpose of this work is to provide a range of effective SLIT dosing based upon a rigorous review of the existing evidence base. An appendix with SLIT dosing recommendations is also included.

METHODS

A comprehensive search of the past 25 years of the medical literature using PubMed was performed for specific antigens. Inclusion criteria for articles included: randomized, placebo-controlled studies of SLIT, studies with clinical allergic rhinitis outcomes, and dosing units available to determine the micrograms per month of major allergen administered. The extracted data was used to compile a range of effective SLIT dosing for individual antigens.

RESULTS

Seventy-five articles met the inclusion criteria, providing a range of effective dosing for some allergens. There was commonly a wide range in doses for particular antigens between the individual studies. For some antigens, there was significant overlap in dosage amount between studies showing efficacy and lack of efficacy. Clinical trials meeting inclusion criteria are not available for many allergens.

CONCLUSION

This study provided a comprehensive review of the published sublingual dosing ranges for specific antigens. The review provided a range of effective sublingual doses for some allergens, whereas for other allergens there was insufficient published data to determine specific doses. Recommendations for SLIT dosing were produced based on the data revealed in the review and expert opinion.

Identification of the cysteine protease Amb a 11 as a novel major allergen from short ragweed

BACKGROUND

Allergy to pollen from short ragweed (Ambrosia artemisiifolia) is a serious and expanding health problem in the United States and in Europe.

OBJECTIVE

We sought to investigate the presence of undescribed allergens in ragweed pollen.

METHODS

Ragweed pollen proteins were submitted to high-resolution gel electrophoresis and tested for IgE reactivity by using sera from 92 American or European donors with ragweed allergy. Pollen transcriptome sequencing, mass spectrometry (MS), and recombinant DNA technologies were applied to characterize new IgE-binding proteins.

RESULTS

High-resolution IgE immunoblotting experiments revealed that 50 (54%) of 92 patients with ragweed allergy were sensitized to a 37-kDa allergen distinct from Amb a 1. The full-length cDNA sequence for this molecule was obtained by means of PCR cloning after MS sequencing of the protein combined with ragweed pollen RNA sequencing. The purified allergen, termed Amb a 11, was fully characterized by MS and confirmed to react with IgEs from 66% of patients. This molecule is a 262-amino-acid thiol protease of the papain family expressed as a combination of isoforms and glycoforms after proteolytic removal of N- and C-terminal propeptides from a proform. Three-dimensional modeling revealed a high structural homology with known cysteine proteases, including the mite Der p 1 allergen. The protease activity of Amb a 11, as well as its capacity to activate basophils from patients with ragweed allergy, were confirmed. The production of a nonglycosylated recombinant form of Amb a 11 in Escherichia coli established that glycosylation is not required for IgE binding.

CONCLUSION

We identified the cysteine protease Amb a 11 as a new major allergen from ragweed pollen. Given the similar physicochemical properties shared by the 2 major allergens, we hypothesize that part of the allergenic activity previously ascribed to Amb a 1 is rather borne by Amb a 11.

Ragweed-induced allergic rhinoconjunctivitis: current and emerging treatment options

Ragweed (Ambrosia spp.) is an annually flowering plant whose pollen bears high allergenic potential. Ragweed-induced allergic rhinoconjunctivitis has long been seen as a major immunologic condition in Northern America with high exposure and sensitization rates in the general population. The invasive occurrence of ragweed (A. artemisiifolia) poses an increasing challenge to public health in Europe and Asia as well. Possible explanations for its worldwide spread are climate change and urbanization, as well as pollen transport over long distances by globalized traffic and winds. Due to the increasing disease burden worldwide, and to the lack of a current and comprehensive overview, this study aims to review the current and emerging treatment options for ragweed-induced rhinoconjunctivitis. Sound clinical evidence is present for the symptomatic treatment of ragweed-induced allergic rhinoconjunctivitis with oral third-generation H1-antihistamines and leukotriene antagonists. The topical application of glucocorticoids has also been efficient in randomized controlled clinical trials. Combined approaches employing multiple agents are common. The mainstay of causal treatment to date, especially in Northern America, is subcutaneous immunotherapy with the focus on the major allergen, Amb a 1. Beyond this, growing evidence from several geographical regions documents the benefit of sublingual immunotherapy. Future treatment options promise more specific symptomatic treatment and fewer side effects during causal therapy. Novel antihistamines for symptomatic treatment are aimed at the histamine H3-receptor. New adjuvants with toll-like receptor 4 activity or the application of the monoclonal anti-immunoglobulin E antibody, omalizumab, are supposed to enhance conventional immunotherapy. An approach targeting toll-like receptor 9 by synthetic cytosine phosphate–guanosine oligodeoxynucleotides promises a new treatment paradigm that aims to modulate the immune response, but it has yet to be proven in clinical trials.

Efficacy and safety of ragweed sublingual immunotherapy in Canadian patients with allergic rhinoconjunctivitis

Background

Currently accepted therapies for ragweed allergy in North America consist of pharmacotherapy and subcutaneous allergen immunotherapy injections to treat symptoms. Allergen immunotherapy not only reduces symptoms and the need for pharmacotherapy but has also been shown to have disease-modifying potential. Recently, ragweed immunotherapy administered via sublingual allergen tablet has been approved in North America for treatment of allergic rhinitis with and without conjunctivitis.

Methods

This was an analysis of pooled data for a prespecified subgroup of Canadian subjects from two multicentre, randomized, double-blind placebo-controlled trials of ragweed sublingual tablet (SLIT-T; 6 and 12 Amb a 1-U of Ambrosia artemisiifolia) in patients aged ≥18y, with ragweed-induced allergic rhinoconjunctivitis (AR/C) with or without asthma. Randomized subjects used once-daily ragweed SLIT-T or placebo for at least 12 weeks before the ragweed season and for up to 52 weeks post-randomization. The primary efficacy endpoint was the total combined score (TCS) based on the sum of AR/C daily symptom score (DSS) and daily medication score (DMS) averaged over the peak season. Treatment effects on TCS, DSS, and DMS in the entire season were also assessed. Adverse events (AEs) were monitored to assess safety.

Results

337 Canadian subjects were randomized in the two trials. During the peak season, ragweed SLIT-T 6 and 12 Amb a 1-U significantly reduced TCS by 26% (difference, -2.46 score point; p = .0009) and 40% (difference, -3.75 score point; p < .0001), respectively. In the overall population (N = 961), TCS reductions with 6 and 12 Amb a 1-U were 20% and 23%, respectively (both p < .001). Clinically meaningful reductions in entire-season TCS in Canadians were similar to those during peak ragweed season. Dose-dependent reduction of DSS and DMS was also observed for ragweed SLIT-T 6 and 12 Amb a 1-U during the peak season and the entire season. Ragweed SLIT-T was well tolerated in Canadian subjects and the overall population. Adverse events were generally mild to moderate and transient, occurring early in treatment; no systemic allergic reaction/anaphylaxis was noted.

Conclusion

Ragweed SLIT-T is an effective form of immunotherapy that provides symptomatic efficacy of AR/C with a favorable risk profile in Canadian and overall populations.

Trial registration

Clinicaltrials.gov identifiers NCT00783198 and NCT00770315.

Immune mechanisms of sublingual immunotherapy

Sublingual immunotherapy (SLIT) is a well-established allergen-specific immunotherapy and a safe and effective strategy to reorient inappropriate immune responses in allergic patients. SLIT takes advantage of the tolerogenic environment of the oral mucosa to promote tolerance to the allergen. Several clinical studies have investigated the complex interplay of innate and adaptive immune responses that SLIT exploits. The oral immune system is composed of tolerogenic dendritic cells that, following uptake of allergen during SLIT, support the differentiation of T helper cell type 1 (Th1) and the induction of IL-10-producing regulatory T cells. Following SLIT, allergic disease-promoting T helper cell type 2 (Th2) responses shift to a Th1 inflammatory response, and IL-10 and transforming growth factor (TGF)-β production by regulatory T cells and tolerogenic dendritic cells suppress allergen-specific T cell responses. These immune changes occur both in the sublingual mucosa and in the periphery of a patient following SLIT. SLIT also promotes the synthesis of allergen-specific IgG and IgA antibodies that block allergen-IgE complex formation and binding to inflammatory cells, thus encouraging an anti-inflammatory environment. Several of these revealing findings have also paved the way for the identification of biomarkers of the clinical efficacy of SLIT. This review presents the emerging elucidation of the immune mechanisms mediated by SLIT.

Sublingual immunotherapy: the U.S. experience

PURPOSE OF REVIEW

It is likely that approval of allergen preparations for sublingual immunotherapy (SLIT) will soon occur in the United States. This article reviews experience with SLIT in this country, concentrating on the large, multicenter trials that will provide the evidence of safety and efficacy necessary to obtain that approval.

RECENT FINDINGS

Large multicenter trials have been conducted with both grass and short ragweed. In five single-season studies with sublingual grass tablets, usually starting 4 months prior to and continuing through the pollen season, the combined symptom medication score was improved 20-28% relative to placebo-treated individuals. Short ragweed tablets, initiated 4 months prior to and continued through the pollen season, reduced symptom/medication scores by 24-26%. Similar results have been reported with short ragweed aqueous extract administered sublingually. To date, there has been only one small study each with house dust mite and cat allergen extracts. All of these studies were conducted with a single allergen. One small study, comparing timothy alone to the same dose of timothy combined with nine other pollen extracts, raised still unanswered questions regarding the efficacy of SLIT with multiple allergen mixes.

SUMMARY

SLIT is coming to the United States. There will be approved allergen preparations for which the appropriate dosing for efficacy and safety has been established. It would be inappropriate to use the evidence generated by these large studies to justify off-label use of allergen extracts approved for injection or the administration of multiple allergen preparations sublingually.

The special challenge of nonadherence with sublingual immunotherapy

Patient nonadherence is a problem that impacts all chronic illness treatments. To determine the degree of nonadherence and its impact on treatment effect in sublingual immunotherapy (SLIT), we conducted a systematic review of published research that assessed adherence or tested interventions to improve SLIT adherence. Adherence to SLIT is similar to other long-term therapies. Across studies, 55% to 82% of patients abandoned SLIT before completing the recommended course of therapy. Only 1 study attempted to test an educational intervention to improve SLIT adherence. Composite evidence indicates that 3 to 5 years of sustained SLIT is required for full long-term benefits, but fewer than half of the patients on SLIT persist to that point. Surprisingly little research has addressed the consequence of partial adherence, including implication to its cost-benefit profile or strategies to improve adherence. Lessons from research into treatments of other chronic health conditions suggest several adherence interventions that may be applied to SLIT, including strategic use of communication and education tools, incorporation of standardized follow-up visits, and employment of telecommunication technologies.

Safety and tolerability of a short ragweed sublingual immunotherapy tablet

BACKGROUND

MK-3641 is a short ragweed sublingual tablet under investigation for immunotherapy of ragweed pollen-induced allergic rhinitis.

OBJECTIVE

To characterize the safety and tolerability of a ragweed sublingual tablet (Merck/ALK-Abelló) in ragweed-allergic adults with or without conjunctivitis.

METHODS

Data from 4 randomized, double-blinded, placebo-controlled trials of MK-3641 (2 28-day and 2 52-week trials) were evaluated. Pooled analyses examined short-term safety over 28 days from all 4 trials and long-term safety from the 52-week trials.

RESULTS

Across all studies, 757, 198, 454, and 1,058 subjects were randomized to placebo or 1.5, 6, or 12 Amb a 1-U of MK-3641, respectively. Treatment-related adverse events were more frequent in the 6- and 12-Amb a 1-U MK-3641 groups than in the placebo group and were primarily local application-site reactions occurring in the first few days of treatment. There was no treatment-associated loss of asthma control or worsening of asthma associated with treatment. No swellings led to airway obstruction or respiratory compromise. No treatment-related anaphylactic shock, life-threatening, or serious treatment-related adverse events were reported for any MK-3641 dose. Of the 1,707 MK-3641-treated subjects, 1 systemic (anaphylactic) reaction was reported (0.06%). The 52-week long-term assessment was generally similar to the safety profile based on the 28-day assessment.

CONCLUSION

MK-3641 doses up to and including 12 Amb a 1-U were well tolerated, with no unexpected safety findings. Sublingual immunotherapy risks such as worsening asthma or airway swellings that could cause airway obstruction were not observed. Systemic reactions and use of epinephrine were uncommon. In these studies, after the first dose was administered in a health care setting, self-administration was well tolerated.

TRIAL REGISTRATION

clinicaltrials.gov Identifiers: NCT01469182, NCT00783198, NCT00770315, and NCT00978029.

Dropouts in sublingual allergen immunotherapy trials - a systematic review

Participant dropouts can reduce the power of allergen immunotherapy clinical trials. Evaluation of the dropout rate and reasons for dropout are important not only in the planning of clinical studies but are also relevant for adherence to immunotherapy in daily clinical practice. A systematic review was carried out in order to establish the overall dropout rate among published double-blind, placebo-controlled randomized clinical trials of sublingual immunotherapy for respiratory allergic diseases. Dropouts were analysed in regards to allergen, formulation, treatment schedule, participant age, study size, number of centres and type of allergic disease. Relative dropout rates in placebo and active groups as well as reasons for dropout were also assessed. A total of 81 studies, comprising 9998 patients, were included. Dropout rates in sublingual immunotherapy controlled studies do not appear to be a major problem with a composite dropout percentage of 14% (95% CI:11.9-16). Furthermore, they are not different for active compared to placebo-treated participants. This lends support to the positive clinical outcomes seen in meta-analyses of these trials.

Sublingual immunotherapy: World Allergy Organization position paper 2013 update

We have prepared this document, "Sublingual Immunotherapy: World Allergy Organization Position Paper 2013 Update", according to the evidence-based criteria, revising and updating chapters of the originally published paper, "Sublingual Immunotherapy: World Allergy Organization Position Paper 2009", available at http://www.waojournal.org. Namely, these comprise: "Mechanisms of sublingual immunotherapy;" "Clinical efficacy of sublingual immunotherapy" - reporting all the data of all controlled trials published after 2009; "Safety of sublingual immunotherapy" - with the recently published Grading System for adverse reactions; "Impact of sublingual immunotherapy on the natural history of respiratory allergy" - with the relevant evidences published since 2009; "Efficacy of SLIT in children" - with detailed analysis of all the studies; "Definition of SLIT patient selection" - reporting the criteria for eligibility to sublingual immunotherapy; "The future of immunotherapy in the community care setting"; "Methodology of clinical trials according to the current scientific and regulatory standards"; and "Guideline development: from evidence-based medicine to patients' views" - including the evolution of the methods to make clinical recommendations.Additionally, we have added new chapters to cover a few emerging crucial topics: "Practical aspects of schedules and dosages and counseling for adherence" - which is crucial in clinical practice for all treatments; "Perspectives and new approaches" - including recombinant allergens, adjuvants, modified allergens, and the concept of validity of the single products. Furthermore, "Raising public awareness about sublingual immunotherapy", as a need for our patients, and strategies to increase awareness of allergen immunotherapy (AIT) among patients, the medical community, all healthcare stakeholders, and public opinion, are also reported in detail.

Randomized, double-blind, placebo-controlled trial of standardized ragweed sublingual-liquid immunotherapy for allergic rhinoconjunctivitis

BACKGROUND

Sublingual immunotherapy with liquid extracts provides an appealing alternative to subcutaneous immunotherapy for the treatment of allergic rhinoconjunctivitis (ARC), but a lack of robust evidence has deterred its use in North America.

OBJECTIVE

To determine the efficacy and tolerability of standardized glycerinated short ragweed sublingual allergen immunotherapy liquid (RW-SAIL) extract in subjects with ragweed-related ARC.

METHODS

This phase 3, randomized, placebo-controlled trial was conducted in North America. Subjects (age range, 18-55 years) with or without asthma were selected based on ARC symptom severity and erythema skin prick reaction to short ragweed. Subjects self-administered the maximum tolerated dose of RW-SAIL (n = 218) or placebo (n = 211) daily beginning approximately 8 to 16 weeks before and through the end of the ragweed pollen season. The primary end point was subject-assessed total combined daily rhinoconjunctivitis symptom and medication scores (TCS).

RESULTS

During the entire season, there was a 43% decrease in TCS in subjects treated with RW-SAIL compared with placebo. Similar decreases were observed in TCS between the 2 groups during peak season (42%) and in daily symptom scores during the entire (42%) and peak (41%) seasons. The occurrence of adverse events was similar between the treatment groups; most were mild in severity. Treatment-related oromucosal local application site reactions occurred early and were transient and self-limited. No anaphylaxis occurred.

CONCLUSIONS

This is the first successful North American confirmatory phase 3 clinical trial to demonstrate the safety and efficacy of a sublingual standardized ragweed allergen immunotherapy liquid extract for the treatment of ARC.

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.

Current and future directions in pediatric allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is a common pediatric problem that significantly affects sleep, learning, performance, and quality of life. In addition, it is associated with significant comorbidities and complications.

OBJECTIVE

The aim was to provide an update on the epidemiology, comorbidities, pathophysiology, current treatment, and future direction of pediatric AR.

METHODS

Literature reviews in each of these areas were conducted, and the results were incorporated.

RESULTS

The prevalence of AR is increasing in the pediatric population and is associated with significant morbidity, comorbidities, and complications. The mainstay of current treatment strategies includes allergen avoidance, pharmacotherapy, and allergen specific immunotherapy.

CONCLUSIONS

In the future, diagnosis will be improved by microarrayed recombinant allergen testing and therapy will be expanded to include emerging treatments such as sublingual immunotherapy and combination products.

New directions in immunotherapy

Allergen immunotherapy (AIT) is effective in reducing the clinical symptoms associated with allergic rhinitis, asthma and venom-induced anaphylaxis. Subcutaneous (SCIT) and sublingual immunotherapy (SLIT) with unmodified allergen extracts are the most widely prescribed AIT regimens. The efficacy of these 2 routes appears comparable, but the safety profile with SLIT is more favorable allowing for home administration and requiring less patient time. However, both require that the treatment is taken regularly over several years, e.g., monthly in a supervised medical setting with SCIT and daily at home with SLIT. Despite the difference in treatment settings, poor adherence has been reported with both routes. Emerging evidence suggests that AIT may be effective in other allergic conditions such as atopic dermatitis, venom sting-induced large local reactions, and food allergy. Research with oral immunotherapy (OIT) for food allergies suggest that many patients can be desensitized during treatment, but questions remain about whether this can produce long term tolerance. Further studies are needed to identify appropriate patients and treatment regimens with these conditions. Efforts to develop safer and more effective AIT for inhalant allergies have led to investigations with modified allergens and alternate routes. Intralymphatic (ILIT) has been shown to produce long-lasting clinical benefits after three injections comparable to a 3-year course of SCIT. Epicutaneous (EPIT) has demonstrated promising results for food and inhalant allergies. Vaccine modifications, such as T cell epitopes or the use of viral-like particles as an adjuvant, have been shown to provide sustained clinical benefits after a relatively short course of treatment compared to the currently available AIT treatments, SLIT and SCIT. These newer approaches may increase the utilization and adherence to AIT because the multi-year treatment requirement of currently available AIT is a likely deterrent for initiating and adhering to treatment.

Diagnostics and new developments in the treatment of ocular allergies

About 30% of people suffer from allergic symptoms, and 40% to 80% of them have eye symptoms. Atopic conjunctivitis is divided into seasonal allergic conjunctivitis and perennial allergic conjunctivitis. The treatment of seasonal allergic conjunctivitis is simple: antihistamines, anti-inflammatory agents, or cromoglycate. Perennial allergic conjunctivitis needs longer therapy with mast cell stabilizers and sometimes local steroids. Atopic keratoconjunctivitis requires long-term treatment of the lid eczema and keratoconjunctivitis. Vernal keratoconjunctivitis mainly affects children and young people. It commonly calms down after puberty. It demands intensive therapy, often for many years, to avoid serious complicating corneal ulcers. Giant papillary conjunctivitis is a foreign body reaction in contact lens users or patients with sutures following ocular surgery. Nonallergic eosinophilic conjunctivitis affects mostly middle-aged and older women with eosinophilic conjunctivitis and dry eye. Contact allergic blepharoconjunctivitis is often caused by cosmetics and eye medication. Work-related ocular allergies should be considered as a cause of resistant ocular symptoms in workplaces.

Regulatory cells in allergen-specific immunotherapy

Allergen-specific immunotherapy (SIT) is currently the best available curative treatment in allergies and has been used for the treatment of patients for the past 100 years. The formation of a Th2 cell predominant inflammation in addition to production of allergen-specific IgE, the attraction of proinflammatory cells and the degranulation of effector cells, such as mast cells, are essential mechanisms in allergy development. Tregs aim to diminish these effects by IL-10- and TGF-β-mediated anti-inflammatory reactions and therefore are one of the main targets in SIT. The induction of allergen tolerance is the key to successful SIT. With a special focus on Tregs, this review aims to clarify what is currently known about allergy development and the mode of action in allergen-SIT, which helps to develop further therapeutic strategies in the fight against allergic diseases.

[Sublingual immunotherapy. Where are we now?]

Allergic diseases represent a global health problem. They affect 20% to 30% of the German population, but more than 40% of the group between 20 and 40 years of age. The symptoms have a considerable influence on social life and cause an impairment of sleep and performance at work/school, leading to a high but avoidable economic impact. For over 100 years specific immunotherapy (SIT) has been used to treat IgE-mediated allergic diseases. Numerous well-controlled studies have provided evidence of its efficacy, safety and tolerability. Today SIT represents a well-established treatment of allergic rhinitis, rhinoconjunctivitis and allergic asthma with a positive health economic impact. Initially, SIT was administered subcutaneously (SCIT), but other routes of application have been developed. In particular the sublingual-swallow method (SLIT) has been proven to be effective and well-tolerated in large studies on grass pollen allergies and represents an additional effective route of administration in adults and children.

Mechanisms of allergen-specific immunotherapy

Allergen-specific immunotherapy (allergen-SIT) is a potentially curative treatment approach in allergic diseases. It has been used for almost 100 years as a desensitizing therapy. The induction of peripheral T cell tolerance and promotion of the formation of regulatory T-cells are key mechanisms in allergen-SIT. Both FOXP3⁺CD4⁺CD25⁺ regulatory T (Treg) cells and inducible IL-10- and TGF-β-producing type 1 Treg (Tr1) cells may prevent the development of allergic diseases and play a role in successful allergen-SIT and healthy immune response via several mechanisms. The mechanisms of suppression of different pro-inflammatory cells, such as eosinophils, mast cells and basophils and the development of allergen tolerance also directly or indirectly involves Treg cells. Furthermore, the formation of non-inflammatory antibodies particularly IgG4 is induced by IL-10. Knowledge of these molecular basis is crucial in the understanding the regulation of immune responses and their possible therapeutic targets in allergic diseases.

IgE-mediated allergy: a rare cause of chronic spontaneous urticarial with allergen-specific immunotherapy as treatment option - a systematic review with meta-analysis from China

BACKGROUND

Allergen-specific immunotherapy (SIT) has long been a controversial treatment for chronic urticaria (CU), although SIT has been used in patients with allergic diseases for more than 90 years.

OBJECTIVES

To evaluate the efficacy and safety of SIT vs. conventional treatment (CT) in the treatment of CU.

METHODS

Systematic searches were conducted without language restrictions in MEDLINE, EMBASE, the Cochrane Library, ISI Web of Knowledge, China National Knowledge Infrastructure, and Chinese Scientific Journals Full Text Database. The primary outcomes were efficacy and quality of life (QOL) and the secondary outcomes were relapse rate and adverse events (AEs).

RESULTS

Fourteen studies (1838 patients) were included. None of them was double-blind placebo controlled. Our study demonstrated that SIT seemed to show more clinical efficacy rate (OR 2.39; 95% CI, 1.73-3.30; I(2) = 55%, P = 0.008), more complete recovery rate (OR 2.13; 95% CI, 1.55-2.91; I(2) = 61%, P=0.008) and less relapse rate 2 weeks after treatment (OR 0.38; 95% CI, 0.24-0.61; I(2) = 6%, P=0.20) than CT. Only one study reported improved QOL and no study reported serious AEs after SIT.

CONCLUSIONS

Current evidence indicates that IgE-mediated allergy may be causative in a small number of CU patients and specific immunotherapy with these allergens may be beneficial in those patients. However, the number of included studies was small and those qualities were low. So, available evidence is not adequate to draw an affirmative conclusion and larger studies of high quality are needed to provide increasingly convincing data and cases.

European Academy of Allergy and Clinical Immunology task force report on 'dose-response relationship in allergen-specific immunotherapy'

BACKGROUND

For a century, allergen-specific immunotherapy (SIT) has proven to be an effective treatment for allergic rhinitis, asthma, and insect sting allergy. However, as allergen doses are frequently adapted to the individual patient, there are few data on dose-response relationship in SIT. Allergen products for SIT are being increasingly required to conform to regulatory requirements for human medicines, which include the need to demonstrate dose-dependent effects.

METHODS

This report, produced by a Task Force of the EAACI Immunotherapy Interest Group, evaluates the currently available data on dose-response relationships in SIT and aims to provide recommendations for the design of future studies.

RESULTS

Fifteen dose-ranging studies fulfilled the inclusion criteria and twelve reported a dose-response relationship for clinical efficacy. Several studies also reported a dose-response relationship for immunological and safety endpoints. Due to the use of different reference materials and methodologies for the determination of allergen content, variations in study design, and choice of endpoints, no comparisons could be made between studies and, as a consequence, no general dosing recommendations can be made.

CONCLUSION

Despite recently introduced guidelines on the standardization of allergen preparations and study design, the Task Force identified a need for universally accepted standards for the measurement of allergen content in SIT preparations, dosing protocols, and selection of clinical endpoints to enable dose-response effects to be compared across studies.

Sublingual immunotherapy

Sublingual immunotherapy (SLIT) has been shown to be safe and efficacious in treating allergic rhinitis. It has been used in Europe for more than 20 years, and interest in the United States is increasing. SLIT has been shown to elicit immunologic changes similar to subcutaneous injection immunotherapy. SLIT may prevent new sensitizations, improve asthma control, and decrease asthma development in allergic individuals. Although differences in antigen quantification and standardization make European dosing schemes difficult to translate in the United States, several new studies suggest the range for effective dosing. Further studies will help clarify optimal dosing.

A review of non-pharmacological and pharmacological management of seasonal and perennial allergic conjunctivitis

Allergic eye disease encompasses a group of hypersensitivity disorders which primarily affect the conjunctiva and its prevalence is increasing. It is estimated to affect 8% of patients attending optometric practice but is poorly managed and rarely involves ophthalmic assessment. Seasonal allergic conjunctivitis (SAC) is the most common form of allergic eye disease (90%), followed by perennial allergic conjunctivitis (PAC; 5%). Both are type 1 IgE mediated hypersensitivity reactions where mast cells play an important role in pathophysiology. The signs and symptoms are similar but SAC occurs periodically whereas PAC occurs year round. Despite being a relatively mild condition, the effects on the quality of life can be profound and therefore they demand attention. Primary management of SAC and PAC involves avoidance strategies depending on the responsible allergen(s) to prevent the hypersensitivity reaction. Cooled tear supplements and cold compresses may help bring relief. Pharmacological agents may become necessary as it is not possible to completely avoid the allergen(s). There are a wide range of anti-allergic medications available, such as mast cell stabilisers, antihistamines and dual-action agents. Severe cases refractory to conventional treatment require anti-inflammatories, immunomodulators or immunotherapy. Additional qualifications are required to gain access to these medications, but entry-level optometrists must offer advice and supportive therapy. Based on current evidence, the efficacy of anti-allergic medications appears equivocal so prescribing should relate to patient preference, dosing and cost. More studies with standardised methodologies are necessary elicit the most effective anti-allergic medications but those with dual-actions are likely to be first line agents.