SQ-standardized sublingual grass immunotherapy: confirmation of disease modification 2 years after 3 years of treatment in a randomized trial

The combination of allergen immunotherapy and biologics for inhalant allergies: Exploring the synergy

The development of monoclonal antibodies that selectively target IgE and type 2 immunity has opened new possibilities in the treatment of allergies. Although they have been used mainly as single therapies found to have efficacy in the management of asthma and other T2-mediated diseases, there is a growing interest in using these monoclonal antibodies in combination with allergen immunotherapy (AIT). AIT has transformed the treatment of allergic diseases by aiming to modify the underlying immune response to allergens rather than just providing temporary symptom relief. Despite the proven efficacy and safety of AIT, unmet needs call for further research and innovation. Combination strategies involving biologics and AIT exhibit potential in improving short-term efficacy, reducing adverse events, and increasing immunologic tolerance. Anti-IgE emerges as the most promising therapeutic strategy, not only enhancing AIT's safety and tolerability but also providing additional evidence of efficacy compared with AIT alone. Anti-interleukin-4 receptor offers a reduction in adverse effects and an improved immunologic profile when combined with AIT; however, its impact on short-term efficacy seems limited. The combination of cat dander subcutaneous immunotherapy with anti-thymic stromal lymphopoietin was synergistic with enhanced efficacy and altered immune responses that persisted for 1 year after discontinuation compared with AIT alone. Long-term studies are needed to evaluate the sustained benefits and safety profiles of combination strategies.

Exploring Side Effects of Sublingual Immunotherapy: A Systemic Review and Meta-Analysis

Objective: Sublingual immunotherapy (SLIT) has emerged as a potentially safe and convenient option for allergen immunotherapy for patients with inhalant allergy. Larger studies on the overall side effects and severe reactions anaphylaxis are still lacking. Study Design: Systematic review and meta-analysis. Setting: Author's review was completed in the University of Texas Medical Branch. Methods: A systematic review and meta-analysis of prospective clinical trials focusing on SLIT safety published from January 1, 2001, to December 31, 2021, was conducted. Results: Twenty-six studies were included with analysis of 7827 patients, representing over 2.7 million SLIT doses. All studies focused on single-antigen immunotherapy. The mean duration of treatment was 11.54 months. Local side effects were present in 40.83% of patients [95% confidence interval (CI) 24.78-57.96]. Systemic side effects were encountered in 1.09% of SLIT patients (95% CI 0.57-1.78). Anaphylaxis was reported in 0.13% of patients (95% CI 0.06-0.22). Discontinuation rates due to side effects were low, at 4.32% of patients (95% CI 3.28-5.49). Conclusion: This meta-analysis shows that single-antigen SLIT is well-tolerated, with overall low rates of systemic side effects including anaphylaxis. Although there is a high rate of minor local side effect, the treatment attrition during the first year is low. With growing allergy burden worldwide, SLIT is a convenient and economically feasible option for immunotherapy. Further work is needed to evaluate long-term safety and efficacy of single as well as multi-antigen SLIT, including quality of life assessments.

Sublingual Tablet Immunotherapy Improves Quality of Life in Adults With Allergic Rhinoconjunctivitis

BACKGROUND

Allergic rhinitis with or without conjunctivitis can negatively impact many aspects of quality of life (QoL). The efficacy and safety of standardized quality (SQ) sublingual immunotherapy (SLIT) tablets have been confirmed across large clinical trials in adults with grass, tree, ragweed, and house dust mite (HDM) allergic rhinitis with or without conjunctivitis.

OBJECTIVE

This pooled analysis investigates whether the reduction in symptom burden found across the clinical trials is supported by improvements in QoL.

METHODS

A total of 11 phase II/III randomized placebo-controlled trials across the SQ grass, tree, ragweed, and HDM SLIT tablets (grass: N = 3179; ragweed: N = 767; tree: N = 634; HDM: N = 2221) were included. QoL was assessed using the standardized Rhinitis Quality of Life Questionnaire (RQLQ), with the exception of 3 grass trials, which used the nonstandardized version. The overall RQLQ scores were expressed as a mean of 7 domains. In the pooled analysis, treatment was used as fixed effect; and the trial, and the interaction between region/country and trial as random effects.

RESULTS

The pooled analysis showed consistent and statistically significant improvements in overall RQLQ scores across all 4 SQ SLIT tablets versus placebo (pooled estimate [95% CI], P value-grass: -0.20 [-0.28 to -0.12], P < .001; tree: -0.42 [-0.58 to -0.26], P < .001; ragweed: -0.36 [-0.55 to -0.17], P < .001; HDM: -0.28 [-0.39 to -0.17], P < .001). Furthermore, significant improvements versus placebo for all 4 SQ SLIT tablets were seen across the 7 individual domains.

CONCLUSIONS

The proven efficacy of SQ SLIT tablets to reduce symptoms across 4 of the most common respiratory allergens is supported by concurrent significant improvements in RQLQ scores overall and for all 7 domains.

Allergen Immunotherapy: The Evidence Supporting the Efficacy and Safety of Subcutaneous Immunotherapy and Sublingual Forms of Immunotherapy for Allergic Rhinitis/Conjunctivitis and Asthma

Allergen immunotherapy (AIT) is a recognized key therapeutic modality for the treatment of allergic respiratory disease. Definitive studies have provided evidence-based data to demonstrate its effectiveness in allergic rhinitis and asthma due to the inhalation of proteinaceous allergic substances from specific seasonal pollens, dust mites, animal allergens, and certain mold spores. Over the ensuing decades, laboratory investigations have provided objective evidence to demonstrate immunologic changes, including production of protective IgG antibody, suppression of IgE antibody, upregulation of regulatory T cells, and induction of a state of immune tolerance to the offending allergen(s). Tangential to this work were carefully designed clinical studies that defined allergen dose and duration of treatment, established the importance of preparing extracts with standardized allergens (or well-defined extracts) based on major protein moieties, and used allergen provocation models to demonstrate efficacy superior to placebo. In the United States, the use of subcutaneous immunotherapy extracts for AIT was grandfathered in by the Food and Drug Administration based on expert literature review. In contrast, sublingual tablet immunotherapy underwent formal clinical development programs (phase I-III clinical trials) that provided the necessary clinical evidence for safety and efficacy that led to regulatory agency approvals for the treatment of allergic rhinitis in properly characterized patients with allergy. The allergy specialist's treatment options currently include traditional subcutaneous AIT and specific sublingual tablets approved for grass, ragweed, house dust mites, trees belonging to the birch-homologous group, and Japanese cedar. Tangential to this are sublingual drops that are increasingly being used off-label (albeit not approved by the Food and Drug Administration) in the United States. This article will review the evidence-based literature supporting the use of these forms of AIT, as well as focus on several current controversies and gaps in our knowledge base that have relevance for the appropriate selection of patients for treatment with specific AIT.

Natural course of pollen-induced allergic rhinitis from childhood to adulthood: A 20-year follow up

BACKGROUND

Allergic rhinitis (AR) is one of the most common chronic diseases worldwide. There are limited prospective long-term data regarding persistency and remission of AR. The objective of this study was to investigate the natural course of pollen-induced AR (pollen-AR) over 20 years, from childhood into early adulthood.

METHODS

Data from 1137 subjects in the Barn/Children Allergi/Allergy Milieu Stockholm Epidemiologic birth cohort (BAMSE) with a completed questionnaire regarding symptoms, asthma, treatment with allergen immunotherapy (AIT) and results of allergen-specific IgE for inhalant allergens at 4, 8, 16 and 24 years were analyzed. Pollen-AR was defined as sneezing, runny, itchy or blocked nose; and itchy or watery eyes when exposed to birch and/or grass pollen in combination with allergen-specific IgE ≥0.35kUA/L to birch and/or grass.

RESULTS

Approximately 75% of children with pollen-AR at 4 or 8 years had persistent disease up to 24 years, and 30% developed asthma. The probability of persistency was high already at low levels of pollen-specific IgE. The highest rate of remission from pollen-AR was seen between 16 and 24 years (21.5%); however, the majority remained sensitized. This period was also when pollen-specific IgE-levels stopped increasing and the average estimated annual incidence of pollen-AR decreased from 1.5% to 0.8% per year.

CONCLUSION

Children with pollen-AR are at high risk of persistent disease for at least 20 years. Childhood up to adolescence seems to be the most dynamic period of AR progression. Our findings underline the close cross-sectional and longitudinal relationship between sensitization, AR and asthma.

Clinical Practice Guideline: Immunotherapy for Inhalant Allergy

OBJECTIVE

Allergen immunotherapy (AIT) is the therapeutic exposure to an allergen or allergens selected by clinical assessment and allergy testing to decrease allergic symptoms and induce immunologic tolerance. Inhalant AIT is administered to millions of patients for allergic rhinitis (AR) and allergic asthma (AA) and is most commonly delivered as subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT). Despite its widespread use, there is variability in the initiation and delivery of safe and effective immunotherapy, and there are opportunities for evidence-based recommendations for improved patient care.

PURPOSE

The purpose of this clinical practice guideline (CPG) is to identify quality improvement opportunities and provide clinicians trustworthy, evidence-based recommendations regarding the management of inhaled allergies with immunotherapy. Specific goals of the guideline are to optimize patient care, promote safe and effective therapy, reduce unjustified variations in care, and reduce the risk of harm. The target patients for the guideline are any individuals aged 5 years and older with AR, with or without AA, who are either candidates for immunotherapy or treated with immunotherapy for their inhalant allergies. The target audience is all clinicians involved in the administration of immunotherapy. This guideline is intended to focus on evidence-based quality improvement opportunities judged most important by the guideline development group (GDG). It is not intended to be a comprehensive, general guide regarding the management of inhaled allergies with immunotherapy. The statements in this guideline are not intended to limit or restrict care provided by clinicians based on their experience and assessment of individual patients.

ACTION STATEMENTS

The GDG made a strong recommendation that (Key Action Statement [KAS] 10) the clinician performing allergy skin testing or administering AIT must be able to diagnose and manage anaphylaxis. The GDG made recommendations for the following KASs: (KAS 1) Clinicians should offer or refer to a clinician who can offer immunotherapy for patients with AR with or without AA if their patients' symptoms are inadequately controlled with medical therapy, allergen avoidance, or both, or have a preference for immunomodulation. (KAS 2A) Clinicians should not initiate AIT for patients who are pregnant, have uncontrolled asthma, or are unable to tolerate injectable epinephrine. (KAS 3) Clinicians should evaluate the patient or refer the patient to a clinician who can evaluate for signs and symptoms of asthma before initiating AIT and for signs and symptoms of uncontrolled asthma before administering subsequent AIT. (KAS 4) Clinicians should educate patients who are immunotherapy candidates regarding the differences between SCIT and SLIT (aqueous and tablet) including risks, benefits, convenience, and costs. (KAS 5) Clinicians should educate patients about the potential benefits of AIT in (1) preventing new allergen sensitizations, (2) reducing the risk of developing AA, and (3) altering the natural history of the disease with continued benefit after discontinuation of therapy. (KAS 6) Clinicians who administer SLIT to patients with seasonal AR should offer pre- and co-seasonal immunotherapy. (KAS 7) Clinicians prescribing AIT should limit treatment to only those clinically relevant allergens that correlate with the patient's history and are confirmed by testing. (KAS 9) Clinicians administering AIT should continue escalation or maintenance dosing when patients have local reactions (LRs) to AIT. (KAS 11) Clinicians should avoid repeat allergy testing as an assessment of the efficacy of ongoing AIT unless there is a change in environmental exposures or a loss of control of symptoms. (KAS 12) For patients who are experiencing symptomatic control from AIT, clinicians should treat for a minimum duration of 3 years, with ongoing treatment duration based on patient response to treatment. The GDG offered the following KASs as options: (KAS 2B) Clinicians may choose not to initiate AIT for patients who use concomitant beta-blockers, have a history of anaphylaxis, have systemic immunosuppression, or have eosinophilic esophagitis (SLIT only). (KAS 8) Clinicians may treat polysensitized patients with a limited number of allergens.

The Art of Dosing for Subcutaneous Immunotherapy in North America

Subcutaneous immunotherapy (SCIT) is a long-established treatment option for allergic rhinoconjunctivitis. Proper dosing of the allergens is critical for the efficacy and safety of SCIT. Of the hundreds of liquid allergen extracts in the United States, effective and well-tolerated SCIT dosing has only been established for a small number. Thus, SCIT dosing remains largely empiric and continues to be, by necessity, an art. To highlight the complexity of SCIT dosing, this review summarizes the historical and current landscape of U.S. allergen extracts, differences among U.S. and European allergen extracts, allergen selection for SCIT, considerations for compounding of allergen extract mixtures, and recommended dosing. As of 2021, 18 standardized allergen extracts are available in the United States; all other extracts remain unstandardized without characterization of allergen content or potency. U.S. allergen extracts differ from European extracts in formulation and potency characterization. There is no standardized methodology for SCIT allergen selection, and interpretation of allergen sensitization is not straightforward. Compounding of SCIT mixtures requires consideration of potential dilution effects, allergen cross-reactivity, proteolytic activity, and additives. Probable effective dose ranges for SCIT are recommended in U.S. allergy immunotherapy practice parameters, although there are few studies using U.S. extracts supporting these doses as therapeutic. In contrast, optimized doses of sublingual immunotherapy tablets have been confirmed in North American phase 3 trials. The SCIT dosing for each patient remains an art that requires clinical experience and consideration of polysensitization, tolerability, compounding of allergen extract mixtures, and the range of recommended doses within the context of extract potency variability.

A Review on Novel Therapeutic Modalities and Evidence-based Drug Treatments against Allergic Rhinitis

Allergic rhinitis (AR) is an IgE-mediated atopic disease that occurs due to inhaled antigens in the immediate phase. Misdiagnosis, insufficient treatment, or no treatment at all are frequent problems associated with the widespread condition known as chronic allergic rhinitis. AR symptoms include runny, itchy, stuffy, and sneezing noses. Asthma and nasal polyps, for example, sometimes occur simultaneously in patients. In order for people living with AR to be as comfortable and productive as possible, treatment should center on reducing their symptoms. The online sources and literature, such as Pubmed, ScienceDirect, and Medline, were reviewed to gather information regarding therapeutic modalities of AR and evidence-based treatments for the disease as the objectives of the present study. An increasing number of people are suffering from AR, resulting in a heavy financial and medical burden on healthcare systems around the world. Undertreating AR frequently results in a decline in quality of life. Treatment compliance is a critical challenge in the administration of AR. Innovative therapies are needed for RA to provide patients with symptom alleviation that is less expensive, more effective, and longer duration of action. Evidence-based guidelines are helpful for managing AR illness. Treating AR according to evidence-based standards can help in disease management. AR treatment includes allergen avoidance, drug therapy, immunotherapy, patient education, and follow-up. However, AR treatment with intranasal corticosteroids is more popular. Hence, in this review article, treatment options for AR are discussed in depth. We also discussed the incidence, causes, and new treatments for this clinical condition.

The KAAACI Guidelines for Sublingual Immunotherapy

Allergen immunotherapy is regarded as the only disease-modifying treatment option for various allergic conditions, including allergic rhinitis and asthma. Among the routes of administration of allergens, sublingual immunotherapy (SLIT) has gained clinical interest recently, and the prescription of SLIT is increasing among patients with allergies. After 30 years of SLIT use, numerous pieces of evidence supporting its efficacy, safety, and mechanism allows SLIT to be considered as an alternative option to subcutaneous immunotherapy. Based on the progressive development of SLIT, the current guideline from the Korean Academy of Asthma, Allergy, and Clinical Immunology aims to provide an expert opinion by allergy, pediatrics, and otorhinolaryngology specialists with an extensive literature review. This guideline addresses the use of SLIT, including 1) mechanisms of action, 2) appropriate patient selection for SLIT, 3) the currently available SLIT products in Korea, and 4) updated information on its efficacy and safety. This guideline will facilitate a better understanding of practical considerations for SLIT.

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.

Prevention Is Better than Cure: Impact of Allergen Immunotherapy on the Progression of Airway Disease

Allergen immunotherapy is highly effective for seasonal pollinosis. Three years of treatment results in long-term efficacy. This disease modification is accompanied by downregulation of allergen-specific Th2 responses and the induction of persistent specific IgG- and IgA-associated IgE-blocking activity. In children with seasonal rhinitis, both subcutaneous and sublingual pollen immunotherapy have been shown to reduce the development of asthma symptoms and asthma medication requirements. House dust mite tablet allergen immunotherapy has been shown to be effective for perennial mite-driven rhinitis in adults and children and may suppress asthma exacerbations, whereas its long-term efficacy has yet to be explored. The success of primary prevention of peanut allergy in childhood by introduction of peanut into the diet during infancy provides a strong rationale to explore whether primary prevention of inhalant allergies and asthma may also be possible. House dust mite allergy is a major risk factor for developing asthma. Preliminary data in at-risk children suggest that sublingual house dust mite immunotherapy initiated during infancy could reduce the onset of multiple allergen sensitizations and prevent the development of asthma at age 6 years. This possibility should now be explored in an adequately powered, prospectively randomized controlled trial.

Clinical relevance of pre- and coseasonal sublingual immunotherapy with a 300 index of reactivity 5-grass SLIT tablet in allergic rhinoconjunctivitis

BACKGROUND

There is considerable interest in improving the scoring methods for evaluating the efficacy of allergen immunotherapy (AIT) and to show if this is associated with clinically meaningful results from the patient's perspective. We aimed to assess the efficacy and clinical relevance of a 300 index of reactivity (IR) 5-grass pollen sublingual immunotherapy (SLIT) tablet in children, adolescents and adults with moderate to severe grass-induced allergic rhinoconjunctivitis (ARC) with or without controlled asthma using the combined symptom and medication score CSMS0-36 .

METHODS

The data of the European population that participated in 3 Phase III, international, randomized double-blind placebo-controlled clinical trials were analyzed post hoc.

RESULTS

A total of 864 patients randomized to 300 IR 5-grass tablet or placebo were analyzed. Over the primary evaluation period, the difference in CSMS0-36 between the 300 IR and placebo groups was statistically significant (point estimates: -2.51, CI95% [-3.88; -1.14], p < 0.0001 in clinical trial1; -2.31, CI95% [-3.39; -1.23], p < 0.0001 in CT2; and -2.31, CI95% [-3.58; -1.03], p = 0.0004 in CT3). The relative differences between the 300 IR 5-grass tablet and placebo were -29.7%, -33.8%, and -26.3%, respectively. The results based on CSMS0-36 were consistent with those obtained with the primary endpoints of the trials and support the consideration of the 2-point threshold of the CSMS0-36 for clinical relevance of AIT.

CONCLUSION

Post hoc analysis of 3 CTs with the 300 IR 5-grass SLIT tablet confirmed its significant and clinically relevant effect in the European population with grass pollen-induced ARC with or without controlled asthma.

Nasal and blood transcriptomic pathways underpinning the clinical response to grass pollen immunotherapy

BACKGROUND

Allergen immunotherapy (AIT) is a well-established disease-modifying therapy for allergic rhinitis, yet the fundamental mechanisms underlying its clinical effect remain inadequately understood. Gauging Response in Allergic Rhinitis to Sublingual and Subcutaneous Immunotherapy was a randomized, double-blind, placebo-controlled trial of individuals allergic to timothy grass who received 2 years of placebo (n = 30), subcutaneous immunotherapy (SCIT) (n = 27), or sublingual immunotherapy (SLIT) (n = 27) and were then followed for 1 additional year.

OBJECTIVE

We used yearly biospecimens from the Gauging Response in Allergic Rhinitis to Sublingual and Subcutaneous Immunotherapy study to identify molecular mechanisms of response.

METHODS

We used longitudinal transcriptomic profiling of nasal brush and PBMC samples after allergen provocation to uncover airway and systemic expression pathways mediating responsiveness to AIT.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01335139, EudraCT Number: 2010-023536-16.

RESULTS

SCIT and SLIT demonstrated similar changes in gene module expression over time. In nasal samples, alterations included downregulation of pathways of mucus hypersecretion, leukocyte migration/activation, and endoplasmic reticulum stress (log2 fold changes -0.133 to -0.640, false discovery rates [FDRs] <0.05). We observed upregulation of modules related to epithelial development, junction formation, and lipid metabolism (log2 fold changes 0.104 to 0.393, FDRs <0.05). In PBMCs, modules related to cellular stress response and type 2 cytokine signaling were reduced by immunotherapy (log2 fold changes -0.611 to -0.828, FDRs <0.05). Expression of these modules was also significantly associated with both Total Nasal Symptom Score and peak nasal inspiratory flow, indicating important links between treatment, module expression, and allergen response.

CONCLUSIONS

Our results identify specific molecular responses of the nasal airway impacting barrier function, leukocyte migration activation, and mucus secretion that are affected by both SCIT and SLIT, offering potential targets to guide novel strategies for AIT.

Causes of Non-Adherence to Allergen-Specific Immunotherapy: A Foundation towards a Patient-Personalized Approach

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only disease-modifying therapy for allergic conditions, resulting in a long-lasting tolerance beyond the duration of the treatment. Due to the strong relationship between the effectiveness, its optimal duration (at least three years) and the observation of the correct administration protocol, appropriate adherence to the plan of treatment represents a critical factor for the therapeutical success of AIT.

METHODS

Analysis of studies about the rate of adherence in subcutaneous and sublingual immunotherapy, which are the main routes of administration of AIT.

RESULTS

There are different causes leading to a premature interruption of the therapy or to it being incorrectly carried out; the most reported include erroneous expectations of the effectiveness and the adverse effects, economic issues, inconvenience and unrelated clinical conditions.

CONCLUSIONS

An attentive analysis of the main causes of dropouts may be useful to improve the management of these patients and to develop new strategies for a personalized approach. These strategies should be dynamic, involving attentive communication between the physician and the patient about all the possible criticalities, especially in the initial phase of the therapy, and facilitating, as much as possible, access to healthcare providers over the course of the maintenance phase, including by exploiting technological tools.

Allergen-specific immunotherapy by recombinant Der P1 allergen-derived peptide-based vaccine in an allergic mouse model

AIM

Increased IgE levels have made house dust mite allergens one of the most frequent causes of allergies worldwide. Treatment reduces the IgE antibodies and types two cytokines, namely interleukin-4 (IL-4) and IL-13. Although existing treatments significantly reduce IgE or IL-4/IL-13, they are very costly. This study aimed to construct a recombinant protein derived from rDer p1 peptides in the form of an immunotherapy approach and to measure the response of IgE and IgG antibodies.

METHODS

The proteins were isolated, purified, and evaluated using the SDS-PAGE and Bradford test and confirmed by using Western blot. To evaluate immunotherapy efficiency, 24 BALB/C mice were sensitized intraperitoneally with house dust mites (HDM) adsorbed to Aluminum hydroxide (Alum) and randomly divided into four groups of six: control sensitized, HDM extract, rDer p1, and DpTTDp vaccine. To immunization, four groups of random mice were each treated with phosphate-buffered saline, 100 μg of rDer p1 protein, DpTTDp, or HDM extract, every 3 days. Direct ELISA determined HDM-specific IgG and IgE subclasses. Data were analyzed in SPSS and Graph pad prism software. Values of p < .05 were considered significant.

RESULTS

After immunization of mice, the rDer P1 and recombinant vaccine like HDM extract increased IgG antibody titer and decreased IgE-dependent reactivity in allergic mice to rDer P1. Also, the levels of inflammatory IL-4 and IL-13 cytokines as allergic stimulants decreased.

CONCLUSION

The use of present available recombinant proteins is considered a viable, cost-effective, and long-term option for providing effective HDM allergy immunotherapy vaccines without side effects.

Mechanisms of Allergen Immunotherapy and Potential Biomarkers for Clinical Evaluation

Allergen-immunotherapy (AIT) is an efficacious and disease-modifying treatment option for IgE-mediated diseases. Among these allergic rhinitis, insect venom allergy, food allergy, and allergic asthma are the most common candidates for AIT. AIT gives rise to clinical immunotolerance which may last for years after the treatment cessation. Mechanisms of AIT include suppression of allergic inflammation in target tissues and stimulation of the production of blocking antibodies, especially IgG4 and IgA. These mechanisms are followed by a reduction of underlying allergen-specific Th2 cell-driven responses to the allergens. Tolerance induction takes place through the desensitization of effector cells and stimulation of regulatory T cells that show their effects by mechanisms involving cell-cell cross-talk, but also other mechanisms, e.g., by the production of immunomodulatory cytokines such as, e.g., IL-10 and TGF-beta. From a personalized medical perspective, there is a need for clinical biomarkers of value in selecting responders and optimizing patient care during AIT. Also, a deeper understanding of underlying mechanistic processes will improve AIT's future outcomes. In this paper, the current knowledge of mechanisms in AIT is reviewed with a special focus on biomarkers of this therapy.

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.

Current advances in house dust mite allergen immunotherapy (AIT): Routes of administration, biomarkers and molecular allergen profiling

Allergy to house dust mites (HDM) is a perennial respiratory disease that affect more than half a billion people worldwide. Dermatophagoides pteronyssinus and D. farinae, two HDM species, are major sources of indoor allergens triggering allergic inflammation. Although symptomatic drugs are widely used to block the allergic reaction, allergen immunotherapy is the only curative treatment of IgE-mediated type I respiratory allergies. In this article, we review recent advances in various routes of allergen immunotherapy. We particularly focus on subcutaneous (SCIT) and sublingual (SLIT) immunotherapy, used as a reference therapy since they have transformed allergic treatments by improving symptoms (asthma and rhinitis) as well as the quality of life of patients. We also highlight recent data in more exploratory routes (i.e., oral, intralymphatic, epicutaneous and intradermal) and discuss respective advantages of various route, as well as their foreseen modes of action. Finally, we provide an update on biomarkers as well as on the relevance of the molecular profiling of allergic individuals related to treatment efficacy or asthma prediction.

A Cost-Utility Analysis of SQ® Tree SLIT-Tablet versus Placebo in the Treatment of Birch Pollen Allergic Rhinitis from a Swedish Societal Perspective

Background and Aims

Allergic rhinitis (AR) is an immunoglobulin E antibody-mediated inflammatory condition that arises in response to inhaled allergens such as pollen. Pollens from trees in the birch homologous group are the most common allergenic tree pollens in Northern and Central Europe and North America. SQ® Tree SLIT-Tablet (ITULAZAX®) is a sublingual immunotherapy tablet indicated for moderate-to-severe AR and/or conjunctivitis induced by pollen from the birch homologous group. The present analysis evaluated the cost-utility of treating adults with AR with SQ Tree SLIT-Tablet versus placebo, both in combination with symptom-relieving medications, from a Swedish societal perspective.

Methods

A model was developed to evaluate changes in cost and quality of life associated with using SQ Tree SLIT-Tablet relative to placebo in an adult population of individuals with AR. The model captured costs associated with symptom-relieving medications, healthcare professional interactions, SQ Tree SLIT-Tablet, and indirect costs arising from absenteeism and reduced workplace productivity. The analysis was conducted over 10 years with costs captured in 2021 Swedish Krona (SEK) and future costs and effects discounted at 3% per annum. One-way and probabilistic sensitivity analyses were conducted.

Results

Treatment with SQ Tree SLIT-Tablet resulted in an improvement of 0.041 quality-adjusted life years (QALYs) over 10 years versus placebo. From a Swedish societal perspective, costs increased by SEK 9077 over the same period, resulting in an incremental cost-utility ratio of SEK 223,445 per QALY gained. One-way sensitivity analysis showed that the model was most sensitive to assumptions around the disease-modifying effect of SQ Tree SLIT-Tablet.

Conclusion

SQ Tree SLIT-Tablet improved quality of life in moderate-to-severe AR and/or conjunctivitis induced by pollen from the birch homologous group in Sweden, with only a modest increase in societal costs over a medium-term time horizon, representing good value for money at a willingness-to-pay threshold of SEK 700,000 per QALY.

Recombinant T-cell epitope conjugation: A new approach for Dermatophagoides hypoallergen design

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only clinical approach that can potentially cure some allergic diseases by inducing immunological tolerance. Dermatophagoides pteronyssinus is considered as the most important source of mite allergens worldwide, with high sensitization rates for the major allergens Der p 1, Der p 2 and Der p 23. The aim of this work is to generate a hypoallergenic hybrid molecule containing T-cell epitopes from these three major allergens.

METHODS

The hybrid protein termed Der p 2231 containing T-cell epitopes was purified by affinity chromatography. The human IgE reactivity was verified by comparing those with the parental allergens. The hybrid was also characterized immunologically through an in vivo mice model.

RESULTS

The hybrid rDer p 2231 stimulated in peripheral blood mononuclear cells (PBMCs) isolated from allergic patients with higher levels of IL- 2, IL-10, IL-15 and IFN-γ, as well as lower levels of IL-4, IL-5, IL-13, TNF-α and GM-CSF. The use of hybrid molecules as a therapeutic model in D. pteronyssinus allergic mice led to the reduction of IgE production and lower eosinophilic peroxidase activity in the airways. We found increased levels of IgG antibodies that blocked the IgE binding to the parental allergens in the serum of allergic patients. Furthermore, the stimulation of splenocytes from mice treated with rDer p 2231 induced higher levels of IL-10 and IFN-γ and decreased the secretion of IL-4 and IL-5, when compared with parental allergens and D. pteronyssinus extract.

CONCLUSIONS

rDer p 2231 has the potential to be used in AIT in patients co-sensitized with D. pteronyssinus major allergens, once it was able to reduce IgE production, inducing allergen-specific blocking antibodies, restoring and balancing Th1/Th2 immune responses, and inducing regulatory T-cells.

Allergen-specific immunotherapy and COVID-19: What happened?

BACKGROUND

The COVID-19 infection played a key role in the discontinuation of patient treatment, such as allergen-specific immunotherapy, in chronic diseases.

OBJECTIVES

We conducted a retrospective observational study at Verona University Hospital, Verona, Italy, to assess the level of adherence to sublingual immunotherapy (SLIT) in patients affected by allergic rhinitis and mild asthma.

MATERIALS AND METHODS

We compared and analysed data related to first prescription and collection of 5-grass-pollen 300-index of reactivity (IR) SLIT and tablet lyophilisate, containing 75,000 standardized quality tablet units (SQ-T) allergen extract of grass-pollen from Phleum pratense L, for the five-year period 2017-2021.In particular we considered the group of naïve patients from 2017 who completed pre-COVID treatment (2017-2019) and the group of naïve patients from 2019 who completed treatment during the COVID period (2019-2021). The significance test used was Student's t-test, and P ˂ 0.05 was considered as statistically significant.

RESULTS

In the three-year period 2017-2019, 264 naïve patients began treatment in 2017, of these 181 continued in 2018, 135 continued in 2019. Instead, for the period 2017-2019, there were 226 naïve patients in 2019; of these 139 continued in 2020, and 102 in 2021.

CONCLUSIONS

COVID-19 did not seem to influence adherence to SLIT, which declined independently even in during the pre-pandemic 3-year period.

Sensitisation profile of Chinese allergic rhinitis patients and effectiveness of a joint allergy-ENT clinic

Purpose

House dust mite (HDM) is the predominant cause of allergic rhinitis (AR) in Hong Kong but remains under-diagnosed and -treated. The association between patient-reported outcome measures (PROMs) and nasoendoscopy findings for AR have also not been investigated. This study investigated the demographics, sensitisation patterns, quality of life, use of sublingual immunotherapy and the association of PROMs and nasoendoscopy findings in AR patients through the first allergist-otorhinolaryngologists AR joint (ARJ) clinic in Hong Kong.

Methods

This single-centred, retrospective observational study was conducted between January 2021 and December 2021. Clinical data from AR patients attending the ARJ clinic were analysed to identify the prevalence of HDM allergens, change in PROMs and the association of PROMs with nasoendoscopy scores.

Results

The three most common sensitising HDM allergens were Dermatophagoides pterynosinus (94.4%), Dermatophagoides farinae (88.9%) and Euroglyphus maynei (88.9%). At the 13- to 32-week follow-up (median 28 weeks), patients who attended the ARJ clinic had significant improvement in Total Nasal Symptom Score (TNSS; p = 0.038). The visual analogue scale (VAS) was associated with nasoendoscopy score (p = 0.018). Patients using SLIT (sublingual immunotherapy) showed overall improvements in PROMs.

Conclusion

The ARJ clinic significantly improved AR symptoms. SLIT was effective and safe for patients who failed conventional treatments. VAS positively correlated with nasoendoscopy findings. Testing for Dermatophagoides pterynosinus as a single agent during skin testing was sufficient for the diagnosis of HDM AR and should be prioritized when resources are restricted. Further studies should be done to investigate the treatment outcome of AR patients and the effectiveness of SLIT in the Chinese population.

Supplementary Information

The online version of this article (10.1007/s40629-022-00218-5) contains supplementary material, which is available to authorized users.

Knowledge mapping of immunotherapy for allergic rhinoconjunctivitis: a bibliometric study (2002-2021)

BACKGROUND

Allergic rhinoconjunctivitis (ARC) is a common chronic inflammatory disease. Numerous studies on the treatment of ARC have been published. By contrast, there are few bibliometric studies on immunotherapy for ARC. The purpose of this article is to describe the current treatments for ARC and to identify the trends in immunotherapy for ARC.

METHODS

Publications were searched from the Web of Science (WOS) Core Collection on April 25, 2022. CiteSpace and Microsoft Excel software were used for further bibliometric analysis.

RESULTS

A total of 969 publications on immunotherapy for ARC in English were retrieved. The number of relevant publications has been continuously increasing over the past 20 years, with many of the publications coming from Germany and the United States of America. In terms of institutions, the ALK Company in Denmark, Imperial College London in United Kingdom, and Charite-Universitatsmedizin Berlin in Germany published the most articles on immunotherapy for ARC. Meanwhile, Allergy and Journal of Allergy and Clinical Immunology published the most number of studies, and Oliver Pfaar from Germany authored the most number of articles. "Subcutaneous immunotherapy," "international consensus," "allergen immunotherapy," and "recommendation" were the most popular subjects. Thus, directions in research can be predicted as studies regarding mechanisms of ARC, clinical trials, and extracts have reported high-quality results.

CONCLUSION

Over the past 20 years, the overall quality of research on immunotherapy for ARC has gradually improved, allowing the introduction of specific and targeted treatment. Currently, the main focus of ARC research is the novel routes of drug delivery and combined treatment with biological agents.

Allergen immunotherapy in treating allergic eosinophilic asthma

Currently, the approach to a patient with asthma is in accordance with personalized medicine wherein the decision on the treatment pathway is based on the type of asthmatic inflammation and other comorbidities that accompany asthma. For an allergic asthma patient, allergen immunotherapy (AIT), which has a disease-modifying effect and the potential to prevent further progression of allergic symptoms, is one of the treatment modalities. It is an effective treatment that, unlike pharmacotherapy, modifies the course of allergic respiratory diseases and induces allergen specific immune tolerance that persists for up to several years after treatment cessation. Therapeutic allergens of high quality, efficacy, and safety according to European regulatory authorities are an integral part of the treatment of respiratory allergies. It is a safe treatment option which still remains the only causal immuno¬modulatory therapy for allergic eosinophilic asthma.

Real-world evidence for the long-term effect of allergen immunotherapy: Current status on database-derived European studies

Randomized controlled trials (RCTs) are the gold-standard for benefit-risk assessments during drug approval processes. Real-word data (RWD) and the resulting real-world evidence (RWE) are becoming increasingly important for assessing the effectiveness of drug products after marketing authorization showing how RCT results are transferred into real life care. The effectiveness of allergen immunotherapy (AIT) has been assessed in several RWE studies based on large prescription databases. We performed a literature search for retrospective cohort assessments of prescription databases in Europe to provide an overview on the methodology, long-term effectiveness outcomes, and adherence to AIT. Thirteen respective publications were selected. AIT was more effective in reducing the progression of allergic rhinitis (AR) compared to a non-AIT control group receiving only symptomatic treatment for AR for up to 6 years. The development and progression of asthma were hampered for most endpoints in patients treated with most preparations compared to the non-AIT group, receiving only anti-asthmatic medication. The results for "time to onset" of asthma were inconsistent. Adherence to AIT decreased during the recommended 3-year treatment period, however, in most studies higher adherence to subcutaneous than to sublingual AIT was shown. The analysis of long-term effectiveness outcomes of the RWE studies based on prescription databases confirms the long-term efficacy of AIT demonstrated in RCTs. Progression of rhinitis and asthma symptoms as well as delayed onset of asthma triggered by different allergens, real life adherence to the treatment shows differences in particular application routes.

Japanese Cedar Pollen Allergens in Japan

Pollen from members of the Cupressaceae tree family is one of the most important causes of allergic disease in the world. Cryptomeria japonica (Japanese cedar) and Chamaecyparis obtusa (Japanese cypress) are Japan's most common tree species. The pollen dispersal season is mainly from February to May. The major allergens of Japanese cedar and Japanese cypress exhibit high amino acid sequence similarity due to the phylogenetic relationship between the two species. An epidemiological study has shown that the prevalence of Japanese cedar pollinosis is approximately 40%. Younger children (5 to 9 years old) showed a high prevalence of Japanese cedar pollinosis as 30% in 2019, indicating that season pollinosis is getting worse. Pharmacotherapy is the most common treatment for pollinosis induced by Japanese cedar and Japanese cypress. Patients' satisfaction with pharmacotherapy is low due to insufficient experienced effect and daytime somnolence. Unlike pharmacotherapy, allergy immunotherapy (AIT) addresses the basic immunological mechanisms of allergic disease and activates protective allergen-reactive pathways of the immune system. AIT is now recognized as the only treatment option with the potential to provide long-term post-treatment benefits and alter the natural course of the allergic disease, including Japanese cedar pollinosis.

Real-world evidence for the long-term effect of allergen immunotherapy: Current status on database-derived European studies

Randomized controlled trials (RCTs) are the gold-standard for benefit-risk assessments during drug approval processes. Real-word data (RWD) and the resulting real-world evidence (RWE) are becoming increasingly important for assessing the effectiveness of drug products after marketing authorization showing how RCT results are transferred into real life care. The effectiveness of allergen immunotherapy (AIT) has been assessed in several RWE studies based on large prescription databases. We performed a literature search for retrospective cohort assessments of prescription databases in Europe to provide an overview on the methodology, long-term effectiveness outcomes, and adherence to AIT. Thirteen respective publications were selected. AIT was more effective in reducing the progression of allergic rhinitis (AR) compared to a non-AIT control group receiving only symptomatic treatment for AR for up to 6 years. The development and progression of asthma were hampered for most endpoints in patients treated with most preparations compared to the non-AIT group, receiving only anti-asthmatic medication. The results for "time to onset" of asthma were inconsistent. Adherence to AIT decreased during the recommended 3-year treatment period, however, in most studies higher adherence to subcutaneous than to sublingual AIT was shown. The analysis of long-term effectiveness outcomes of the RWE studies based on prescription databases confirms the long-term efficacy of AIT demonstrated in RCTs. Progression of rhinitis and asthma symptoms as well as delayed onset of asthma triggered by different allergens, real life adherence to the treatment shows differences in particular application routes.

Immunology of allergen immunotherapy

Allergen immunotherapy (AIT) is the only disease-modifying therapy for allergic disease. Through repeated inoculations of low doses of allergen-either as whole proteins or peptides-patients can achieve a homeostatic balance between inflammatory effectors induced and/or associated with allergen contact, and mediators of immunologic non-responsiveness, potentially leading to sustained clinical improvements. AIT for airborne/respiratory tract allergens and insect venoms have traditionally been supplied subcutaneously, but other routes and modalities of administration can also be effective. Despite differences of allergen administration, there are some similarities of immunologic responses across platforms, with a general theme involving the restructuring and polarization of adaptive and innate immune effector cells. Here we review the immunology of AIT across various delivery platforms, including subcutaneous, sublingual, epicutaneous, intradermal, and intralymphatic approaches, emphasizing shared mechanisms associated with achieving immunologic non-responsiveness to allergen.

Allergen immunotherapy: past, present and future

Allergen immunotherapy is a form of therapeutic vaccination for established IgE-mediated hypersensitivity to common allergen sources such as pollens, house dust mites and the venom of stinging insects. The classical protocol, introduced in 1911, involves repeated subcutaneous injection of increasing amounts of allergen extract, followed by maintenance injections over a period of 3 years, achieving a form of allergen-specific tolerance that provides clinical benefit for years after its discontinuation. More recently, administration through the sublingual route has emerged as an effective, safe alternative. Oral immunotherapy for peanut allergy induces effective ‘desensitization’ but not long-term tolerance. Research and clinical trials over the past few decades have elucidated the mechanisms underlying immunotherapy-induced tolerance, involving a reduction of allergen-specific T helper 2 (T_H2) cells, an induction of regulatory T and B cells, and production of IgG and IgA ‘blocking’ antibodies. To better harness these mechanisms, novel strategies are being explored to achieve safer, effective, more convenient regimens and more durable long-term tolerance; these include alternative routes for current immunotherapy approaches, novel adjuvants, use of recombinant allergens (including hypoallergenic variants) and combination of allergens with immune modifiers or monoclonal antibodies targeting the T_H2 cell pathway.

Durham and Shamji review the history and future of allergen immunotherapy for established IgE-mediated hypersensitivity to common allergens. They describe the mechanisms of immunotherapy-induced tolerance and the new strategies being explored to achieve safer, more effective, long-term tolerance.

Pharmacological Management of Allergic Rhinitis: A Consensus Statement from the Malaysian Society of Allergy and Immunology

The goal of allergic rhinitis (AR) management is to achieve satisfactory symptom control to ensure good quality of life. Most patients with AR are currently treated with pharmacotherapy. However, knowledge gaps on the use of pharmacotherapy still exist among physicians, particularly in the primary care setting, despite the availability of guideline recommendations. Furthermore, it is common for physicians in the secondary care setting to express uncertainty regarding the use of new combination therapies like intranasal corticosteroid plus antihistamine combinations. Inadequate treatment leads to significant reduction of quality of life that affects daily activities at home, work, and school. With these concerns in mind, a practical consensus statement was developed to complement existing guidelines on the rational use of pharmacotherapy in both the primary and secondary care settings.

Barriers to accessing aeroallergen immunotherapy in paediatrics

BACKGROUND

Allergen immunotherapy (AIT) is a safe, effective and disease-modifying treatment for allergic rhinitis. It is indicated for children with moderate to severe disease whose symptoms persist despite conventional therapy. There is a high prevalence of allergic rhinitis amongst Irish children; however, levels of AIT prescribing in Ireland are lower than neighbouring countries.

AIMS

The aims of this study are to describe current patterns of AIT prescribing and referrals amongst Irish paediatricians and to identify barriers to accessing AIT in Ireland.

METHODS

An electronic questionnaire was distributed to all paediatricians and paediatric trainees caring for children with allergic rhinitis.

RESULTS

A lack of knowledge of AIT clinical criteria was the most frequently reported barrier with 50.5% (50/99) of general paediatricians unaware of the indications for referral compared to 27.3% (3/11) of respiratory physicians and 0% (0/8) of allergists. Accessibility is the next most cited barrier with 31.4% (37/118) of respondents unsure where to refer and 19.5% (23/118) reporting a lack of local services. Cost was reported to be a barrier by 12.7% (15/118). Paediatricians with an allergy or respiratory subspecialisation reported seeing significantly higher numbers of children with allergic rhinitis and were more likely to prescribe or refer a child for AIT.

CONCLUSIONS

This study demonstrated positive attitudes towards AIT amongst all grades and specialities of paediatricians in Ireland. The main barriers to more widespread use are difficulties with the identification of suitable candidates by general paediatricians and a lack of local AIT services and referral pathways.

Long-term efficacy of the sublingual and subcutaneous routes in allergen immunotherapy

Allergen immunotherapy is highly effective in selected patients with allergic rhinitis, allergic asthma, and Hymenoptera venom allergy. Unlike anti-allergic drugs, both subcutaneous and sublingual immunotherapies have been shown to modify the underlying cause of the disease, with proved long-term clinical benefits after treatment cessation. In this review, we analyzed 10 randomized, double-blind, placebo controlled clinical trials of allergen immunotherapy that included blinded follow-up for at least 1 year after treatment withdrawal. Three studies of pollen subcutaneous immunotherapy provided evidence that a sustained, tolerogenic effect of subcutaneous immunotherapy can be achieved after 3 years of treatment. Six trials of sublingual immunotherapy provided robust evidence for long-term clinical benefit and persistent immunologic changes after grass pollen, house-dust mite, or Japanese cedar immunotherapy, whereas a clinical trial of both sublingual and subcutaneous grass pollen immunotherapies showed that 2 years of immunotherapy were efficacious but insufficient to induce long-term tolerance. These studies strongly supported international guidelines that recommend at least 3 years of allergen immunotherapy of proven value to achieve disease modification and sustained clinical and immunologic tolerance.

Efficacy and safety of sublingual allergen immunotherapy

Sublingual immunotherapy (SLIT)-tablets represent a new allergen immunotherapy option for clinicians. In North America, there are five SLIT-tablets approved for the treatment of allergic rhinoconjunctivitis (ARC). No SLIT-drops products are currently approved in the United States or Canada. This work reviewed the efficacy of the timothy grass SLIT-tablet, five-grass SLIT-tablet, ragweed SLIT-tablet, house-dust mite SLIT-tablet, and tree SLIT-tablet in patients with ARC. All the SLIT-tablets showed consistent clinical efficacy for the treatment of ARC in large, double-blind, placebo-controlled trials, including for both patients who were monosensitized and those who were polysensitized. Treatment with house-dust mite SLIT-tablet has shown efficacy in patients who are pollen sensitized during their respective pollen seasons. In contrast to SLIT-tablets, efficacy studies of SLIT-drops show high heterogeneity of treatment effect. Although data are scarce, data that compared the efficacy of SLIT-tablets versus ARC pharmacotherapy generally indicated that SLIT-tablets had a greater benefit than pharmacotherapy when compared with placebo, particularly for perennial ARC. When compared with subcutaneous immunotherapy, analysis of these data indicated that SLIT-tablets had a benefit over subcutaneous immunotherapy in regard to safety but somewhat less benefit in regard to efficacy. The safety of SLIT-tablets has been well documented, and a U.S. Food and Drug Administration class label with safety considerations is present in the prescribing information for all SLIT-tablets. No new safety signals have been observed after reinitiating SLIT-tablets after a short treatment interruption.

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.

Mast Cell Desensitization in Allergen Immunotherapy

Allergen immunotherapy (AIT) is the only treatment with disease-transforming potential for allergic disorders. The immunological mechanisms associated with AIT can be divided along time in two phases: short-term, involving mast cell (MC) desensitization; and long-term, with a regulatory T cell (Treg) response with significant reduction of eosinophilia. This regulatory response is induced in about 70% of patients and lasts up to 3 years after AIT cessation. MC desensitization is characteristic of the initial phase of AIT and it is often related to its success. Yet, the molecular mechanisms involved in allergen-specific MC desensitization, or the connection between MC desensitization and the development of a Treg arm, are poorly understood. The major AIT challenges are its long duration, the development of allergic reactions during AIT, and the lack of efficacy in a considerable proportion of patients. Therefore, reaching a better understanding of the immunology of AIT will help to tackle these short-comings and, particularly, to predict responder-patients. In this regard, omics strategies are empowering the identification of predictive and follow-up biomarkers in AIT. Here, we review the immunological mechanisms underlying AIT with a focus on MC desensitization and AIT-induced adverse reactions. Also, we discuss the identification of novel biomarkers with predictive potential that could improve the rational use of AIT.

The Role of Allergen-Specific Immunotherapy in ENT Diseases: A Systematic Review

Previous studies have demonstrated that both subcutaneous (SCIT) and sublingual specific immunotherapy (SLIT) are effective in treating allergic rhinitis (AR). Further studies have evaluated the efficacy of allergen-specific immunotherapy (AIT) on different ear, nose, and throat (ENT) manifestations, in which allergy might have an etiopathogenetic role, such as local allergic rhinitis (LAR), rhinosinusitis (RS), otitis media (OM), and adenotonsillar (AT) disease. Nevertheless, the management of allergy in ENT diseases is still debated. To the best of our knowledge, this is the first systematic review assessing the efficacy of AIT in ENT diseases aside from AR. Literature data confirmed that AIT might be an effective therapeutic option in LAR, although its effect is restricted to studies with short-term follow-up. Furthermore, previous research demonstrated that AIT may improve symptoms and surgical outcomes of chronic rhinosinusitis when used as an adjunctive treatment. Few studies supported the hypothesis that AIT may exert positive therapeutic effects on recurrent upper airway infections as adenotonsillar disease. Finally, some clinical observations suggested that AIT may add some benefits in the management of otitis media with effusion (OME). The results of this systematic review allow us to conclude that the efficacy of AIT in ENT disorders has been only slightly investigated and additional studies are needed.

Coordinated IgG2 and IgE responses as a marker of allergen immunotherapy efficacy

BACKGROUND

IgG2 responses are associated with repeated antigen exposure and display highly mutated variable domains. A recent study highlighted a role of IgG2+ memory B cells and allergen-specific IgG2 levels after a 3rd consecutive pre-seasonal sublingual allergen immunotherapy (AIT) with grass pollen tablet. Herein, we aim to explore changes in allergen-specific IgG2 in individuals undergoing house dust mite immunotherapy (HDM-AIT) and explore whether the interrelationship with other humoral responses (i.e., IgG4 and IgE) may discriminate between high and low responders.

METHODS

Levels of serum Dermatophagoides pteronyssinus and Dermatophagoides farinae-specific IgG2, IgG4, and IgE antibodies were measured by ELISA or ImmunoCap in a sub-group of individuals enrolled in a randomized, double-blind, placebo-controlled, sublingual AIT study evaluating the safety and efficacy of a 300 IR HDM tablet.

RESULTS

After 1-year sublingual AIT, HDM-specific serum IgG2 responses increase mostly in high versus low responders and are distinctive according to the clinical benefit. Higher correlation between HDM-specific IgG2, IgE, and/or IgG4 responses is seen in subjects benefiting the most from HDM-AIT as indicated by changes in Average Total Combined Scores. More strikingly, statistically significant correlation between HDM-specific IgG2 and IgE responses is only observed in individuals stratified as high responders.

CONCLUSIONS

We provide evidence for coordinated serum immune responses upon AIT in HDM-allergic subjects exhibiting high clinical benefit when compared with low responders. Assessing HDM-specific IgE, IgG2, and IgG4 in serum could be used as follow-up combined markers to support decision as to AIT continuation and/or adaptation.

Current unmet needs and potential solutions to uncontrolled asthma

Despite the availability of effective inhaled therapies, many patients with asthma have poor asthma control. Uncontrolled asthma presents a significant burden on the patient and society, and, for many, remains largely preventable. There are numerous reasons why a patient may remain uncontrolled despite access to therapies, including incorrect inhaler technique, poor adherence to treatment, oversight of triggers and suboptimal medical care. Shared decision-making, good patient–clinician communication, supported self-management, multidisciplinary patient education, new technology and risk stratification may all provide solutions to this major unmet need in asthma. Novel treatments such as biologics could benefit patients’ lives, while the investigations into biomarkers, non-Type 2 asthma, treatable traits and disease modification give an exciting glimpse into the future of asthma care.

Despite effective therapies, many patients with asthma have poor asthma control, which is preventable. The benefits of shared decision-making, supported self-management, risk stratification and novel treatments in transforming patient care are reviewed.https://bit.ly/3A386Nm

Alternatives to Subcutaneous Immunotherapy for Allergic Rhinitis

Allergic rhinitis (AR) is an important public health issue worldwide due to its increasing prevalence and impact on quality of life, school performance, and work productivity. Subcutaneous immunotherapy (SCIT) is used to treat AR and involves repeated injections of allergen extracts. SCIT is used for cases of severe AR with symptoms that are not adequately controlled by medication, when the side effects of medication limit treatment options, or where the aim is to cure rather than symptomatically treat. Although SCIT is effective, it is not necessarily curative. Furthermore, there is also a low but present risk of systemic allergic reactions, with systemic side effects occurring in less than 0–1% of treated patients. Sublingual immunotherapy (SLIT) has emerged as an effective and safe alternative to SCIT. SCIT and SLIT are the only immunotherapies currently available for AR. In addition to sublingual administration as an alternative to SCIT, other routes of antigen administration have been attempted with the goal of increasing safety while maintaining efficacy. This review discusses the efficacies of SCIT and SLIT, their mechanisms, the utility of intralymphatic immunotherapy (ILIT) as an alternative route of antigen administration, and the potential for immunotherapy using other routes of antigen administration.

Specific IgE and IgG4 Profiles of House Dust Mite Components in Allergen-Specific Immunotherapy

Background

Allergen immunotherapy (AIT) can induce immune tolerance to allergens by activating multiple mechanisms, including promoting IgG4 synthesis and blunting IgE production. However, the longitudinal data of sIgE and sIgG4 to allergen components during AIT are limited.

Objective

We sought to investigate the persistence and evolution of sIgE and sIgG4 against house dust mite (HDM) components during AIT and explore their correlation with clinical responses.

Methods

Sixty allergic rhinitis (AR) with/without asthma patients receiving AIT for HDM were enrolled in AIT group. Thirty AR patients without receiving AIT served as control group. Blood samples were collected for sIgE, sIgG4 to HDM components (Derp 1, Derf 1, Derp 2, Derf 2, Derp 7, Derp 10, Derp 21 and Derp 23) assay at baseline, Month 6 and Month 18 of AIT. Combined symptom and medication scores (CSMS) were obtained accordingly.

Results

In the AIT group, sIgG4 to the HDM components of Derp 1, Derf 1, Derp 2 and Derf 2, Derp 21 significantly increased at Month 18 compared to the baseline (36.2 U_A/mL vs 158.8 U_A/mL, 46.4 U_A/mL vs 94.6 U_A/mL, 80.5 U_A/mL vs 152.3 U_A/mL, 78.3 U_A/mL vs 205.1 U_A/mL, 42.3 U_A/mL vs 59.3 U_A/mL, all p<0.05), sIgE to HDM components didn’t see differences at baseline and at Month 18 (all p>0.05).The numbers of positive HDM component sIgE and sIgG4 increased from 4.5 to 5 and 0 to 1.5 respectively (both p<0.05). However, the changes of sIgE, sIgG4, sIgE/sIgG4 ratio and the numbers of positive HDM components had no correlations with the improvement of CSMS after AIT (all ρ<0.3). For the control group, the sIgE and sIgG4 did not change significantly during the observational period (all p>0.05).

Conclusion

AIT can induce the production of sIgG4 to HDM components. However, the increased sIgG4 levels of HDM component do not correlate with the corresponding sIgE levels at baseline or with AIT response. sIgG4 to HDM components do not qualify as a biomarker to evaluate the efficacy of AIT.

Preference for sublingual immunotherapy with tablets in a Spanish population with allergic rhinitis

Background

This study investigated patients' preference for allergy immunotherapy (AIT) administered as either sublingual immunotherapy‐tablets versus monthly or weekly subcutaneous immunotherapy (SCIT) from a Spanish patient perspective.

Methods

A discrete choice experiment (DCE) consisting of two blocks with eight choice sets in each was constructed to elicit the preferences for AIT. Three attributes were included in the DCE for the mode of administration, including the frequency of administration, the risk of systemic reactions and the co‐payment. Adults and caregivers of children with moderate to severe allergic rhinitis (AR) were included if they were not currently receiving or had not previously received AIT.

Results

In total, 587 adults and 613 caregivers started the survey. Of those, 579 adults and 611 caregivers completed the survey and were included in the study. Both adults and caregivers had a significant preference for tablets compared with both monthly and weekly injections (p ≤ 0.0001). Furthermore, the respondents showed a significant preference for reducing the risk of systemic reactions. Subgroup analyses showed that caregivers of polyallergic children and female caregivers were significantly less price sensitive when choosing their preferred treatment.

Conclusion

Our study demonstrated that both adults with AR and caregivers of children with AR prefer daily SLIT‐tablets to SCIT with either a weekly or monthly dose schedule.

One hundred and ten years of Allergen Immunotherapy: A journey from empiric observation to evidence

One hundred and ten years after Noon's first clinical report of the subcutaneous application of allergen extracts, allergen immunotherapy (AIT) has evolved as the most important pillar of the treatment of allergic patients. It is the only disease-modifying treatment option available and the evidence for its clinical efficacy and safety is broad and undisputed. Throughout recent decades, more insights into the underlying mechanisms, in particular the modulation of innate and adaptive immune responses, have been described. AIT is acknowledged by worldwide regulatory authorities, and following the regulatory guidelines for product development, AIT products are subject to a rigorous evaluation before obtaining market authorization. Knowledge and practice are anchored in international guidelines, such as the recently published series of the European Academy of Allergy and Clinical Immunology (EAACI). Innovative approaches continue to be further developed with the focus on clinical improvement by, for example, the usage of adjuvants, peptides, recombinants, modification of allergens, new routes of administration, and the concomitant use of biologicals. In addition, real-life data provide complementary and valuable information on the effectiveness and tolerability of this treatment option in the clinical routine. New mobile health technologies and big-data approaches will improve daily treatment convenience, adherence, and efficacy of AIT. However, the current coronavirus disease 2019 (COVID-19) pandemic has also had some implications for the feasibility and practicability of AIT. Taken together, AIT as the only disease-modifying therapy in allergic diseases has been broadly investigated over the past 110 years laying the path for innovations and further improvement.

Allergen Immunotherapy: Current and Future Trends

Allergen immunotherapy (AIT) is the sole disease-modifying treatment for allergic rhinitis; it prevents rhinitis from progressing to asthma and lowers medication use. AIT against mites, insect venom, and certain kinds of pollen is effective. The mechanism of action of AIT is based on inducing immunological tolerance characterized by increased IL-10, TGF-β, and IgG4 levels and Treg cell counts. However, AIT requires prolonged schemes of administration and is sometimes associated with adverse reactions. Over the last decade, novel forms of AIT have been developed, focused on better allergen identification, structural modifications to preserve epitopes for B or T cells, post-traductional alteration through chemical processes, and the addition of adjuvants. These modified allergens induce clinical-immunological effects similar to those mentioned above, increasing the tolerance to other related allergens but with fewer side effects. Clinical studies have shown that molecular AIT is efficient in treating grass and birch allergies. This article reviews the possibility of a new AIT to improve the treatment of allergic illness.

Allergen Release Profiles of Fast-Dissolving Freeze-Dried Orodispersible Sublingual Allergy Immunotherapy Tablets

Background

Sublingual allergy immunotherapy tablets (SLIT-tablets) provide a well-tolerated and clinically efficacious treatment for allergic disease such as allergic rhinitis and allergic asthma. In SLIT, uptake of allergen by immune-competent cells in the oral mucosa activates the immune system and leads to tolerance toward the sensitizing allergen. The ability to deliver the full allergen content into solution within the recommended sublingual holding time is therefore an essential quality of SLIT-tablets that must be supported by the tablet formulation for all relevant allergen sources. SLIT-tablets based on a fast-dissolving orodispersible freeze-dried formulation (Zydis) are currently available for 5 of the most prevalent allergens: tree (birch and related species from the birch-homologous group), grass, ragweed, Japanese cedar, and house dust mite.

Objectives

The purpose of this study was to examine the allergen release properties of three freeze-dried SLIT-tablets containing tree, ragweed, and Japanese cedar extracts, respectively. The correlation between SLIT-tablet allergen release and the level of allergen-specific T-cell activation was examined for the tree SLIT-tablet.

Methods

Allergen release kinetics and tablet disintegration times for the 3 freeze-dried SLIT-tablets were examined. For all 3 tablets, the magnitude of solubilized major allergen relative to time in solution was compared to external controls to achieve a measure of the total allergen release. Additional assessments of allergen release occurring after the initial timepoint (15 or 30 seconds in solution) were done independently of external controls by linear regression analyses. For the tree SLIT-tablet, the immunological potency of the released major allergen was assessed at each experimental timepoint by a Bet v-specific T-cell activation assay.

Results

All 3 SLIT-tablets disintegrated within 1 second after contact with assay buffer without any detectible residue. Complete release of major allergens (Bet v 1, Amb a 1, and Cry j 1, respectively) was seen at the earliest experimental time points (15 or 30 seconds). For the tree SLIT-tablet, full T-cell activation was achieved at 30 seconds (earliest experimental time point).

Conclusions

The freeze-dried SLIT-tablet formulation consistently provides rapid and complete release of allergen from a wide range of species in a standardized in vitro assay. Full release of the SLIT-tablet allergen content within the sublingual holding time is a prerequisite for maximal exposure of allergens to the sublingual mucosa immune system. The freeze-dried SLIT-tablet formulation examined here supports short sublingual holding times and furthermore offers a convenient administration form of allergy immunotherapy.