Prolonged efficacy of the 300IR 5-grass pollen tablet up to 2 years after treatment cessation, as measured by a recommended daily combined score

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.

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.

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.

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.

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.

Nasal microbes in allergic rhinitis children with or without sublingual immunotherapy

The mechanism of allergic rhinitis (AR) remains unclear. Most researchers believe that AR is the result of a combination of environmental and genetic factors. Sublingual immunotherapy (SLIT) is a treatment that can change the natural course of AR through immunomodulatory mechanism and maintain efficacy after the treatment. Nasal cavity is the main site where AR patients contact with external allergens, produce inflammatory reactions and nasal symptoms. Therefore, in this study, we investigate the nasal microbiome in AR patients, and the changes after SLIT. In this cross-sectional study, nasal swabs for microbiome analysis were collected from 3 groups: SLIT-naïve AR patients (AR group), AR patients undergoing SLIT treatment over 2 years (SLIT group) and a control group (CG). The characteristics of nasal microbiome of each groups were produced by 16s-rDNA sequencing technology. The Simpson index of AR group was significantly higher than that of CG and SLIT groups, but not different between SLIT group and CG group. The abundance of Bacteroidete and Firmicutes remarkably increased in the AR group, but Bacteroidete reduced to CG level after SLIT. AR patients have different nasal microbiome composition, but we do not know how it happened and whether the AR condition affected nasal microbiome composition or nasal microbiome affected AR.

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.

Nonallergic Rhinitis, Allergic Rhinitis, and Immunotherapy: Advances in the Last Decade

Chronic rhinitis encompassing both allergic and nonallergic rhinitis affects a significant portion of the population worldwide, having a great impact on patient quality of life, and associated comorbid conditions, with an important societal economic burden. Allergists are often the first to evaluate and treat allergic and nonallergic rhinitis, addressing the individual triggers of the disease as well as the patient-specific responses to these triggers. This review focuses on the advances that have been made in the diagnosis, management, and treatment of nonallergic and allergic rhinitis over the past 10 years, including specific allergen immunotherapy, care pathways, and digital health.

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.

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.

Subcutaneous birch pollen allergen immunotherapy with a depigmented polymerized extract shows only sustained and long-term efficacy in a subgroup of monosensitized adults and adolescents with allergic rhinitis

Background

Allergen immunotherapy (AIT) is an approved treatment for seasonal respiratory allergic diseases. A depigmented polymerized birch pollen extract for subcutaneous allergen immunotherapy (SCIT) has been demonstrated to be efficacious and safe in patients allergic to birch pollen and its homologous group.

Objective

To determine whether SCIT with a birch pollen formulation (5000 depigmented polymerized (DPP) units/mL) shows sustained and long‐term efficacy in adults and adolescents with birch‐pollen induced allergic rhinitis with or without intermittent asthma.

Methods

A multicentre (n = 66), double‐blind, placebo‐controlled Phase III clinical trial was performed in the Czech Republic, Finland, Germany, Latvia, Lithuania, Poland and Russia. Participants were randomized 2:1 to active treatment (birch 5000 DPP/ml) or placebo for three years of SCIT and followed up for two treatment‐free years. The primary efficacy endpoint was the EAACI's combined symptom and medication score for rhinoconjunctivitis (CSMS_EAACI).

Results

A total of 973 participants were screened and 649 were randomized (active treatment: n = 434; placebo: n = 215). The intention‐to‐treat analysis of the CSMS_EAACI in the overall study population did not demonstrate statistically significant differences in years 1, 2 and 3. In a post‐hoc analysis, among the subgroup of patients monosensitized to birch pollen allergen only (n = 200), we observed a statistically significant difference (active treatment vs. placebo) in the CSMS_EAACI in year 2, 3 and 5. The AIT's safety profile was good.

Conclusions

SCIT with a depigmented polymerized birch pollen extract was safe. Sustained and long‐term efficacy in years 2, 3 and 5 in monosensitized patients, but not in polysensitized patients was demonstrated.

(EudraCT 2012‐000414‐11)

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.

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.

Update about Oralair® as a treatment for grass pollen allergic rhinitis

Sublingual immunotherapy (SLIT) is a well-tolerated, safe, and effective approach to treating allergic rhinitis (AR). Oralair® is a five-grass pollen SLIT tablet containing natural pollen allergens from five of the major grass species responsible for seasonal AR due to grass pollen allergy. Recommended use is in a pre-coseasonal regimen, starting daily treatment approximately 4 months before the start of the pollen season, with treatment then continued daily throughout the season; treatment should continue for 3–5 y. Clinical efficacy and safety of Oralair® in patients with grass pollen-induced AR has been demonstrated in a comprehensive clinical development program of randomized controlled trials. Effectiveness has been substantiated in subsequent observational studies with sustained efficacy following treatment cessation and a favorable level of adherence, quality of life, benefit, and satisfaction for the patients. Supportive evidence for a benefit in reducing the risk or delaying the development of allergic asthma is emerging.

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.

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.

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.

Allergic Rhinitis: What Do We Know About Allergen-Specific Immunotherapy?

Allergic rhinitis (AR) is an IgE-mediated disease that is characterized by Th2 joint inflammation. Allergen-specific immunotherapy (AIT) is indicated for AR when symptoms remain uncontrolled despite medication and allergen avoidance. AIT is considered to have been effective if it alleviated allergic symptoms, decreased medication use, improved the quality of life even after treatment cessation, and prevented the progression of AR to asthma and the onset of new sensitization. AIT can be administered subcutaneously or sublingually, and novel routes are still being developed, such as intra-lymphatically and epicutaneously. AIT aims at inducing allergen tolerance through modification of innate and adaptive immunologic responses. The main mechanism of AIT is control of type 2 inflammatory cells through induction of various functional regulatory cells such as regulatory T cells (Tregs), follicular T cells (Tfr), B cells (Bregs), dendritic cells (DCregs), innate lymphoid cells (IL-10⁺ ILCs), and natural killer cells (NKregs). However, AIT has a number of disadvantages: the long treatment period required to achieve greater efficacy, high cost, systemic allergic reactions, and the absence of a biomarker for predicting treatment responders. Currently, adjunctive therapies, vaccine adjuvants, and novel vaccine technologies are being studied to overcome the problems associated with AIT. This review presents an updated overview of AIT, with a special focus on AR.

Patient needs and benefits of sublingual immunotherapy for grass pollen-induced allergic rhinitis: an observational study

Aim: Clinical efficacy of sublingual immunotherapy for grass pollen-induced allergic rhinitis (AR) needs to translate into patient benefit. Patients & methods: Patients received Oralair (Stallergenes, Antony, France) in real-life medical practice. Patient-relevant treatment benefits were measured with the AR-specific Patient Benefit Index. Subgroups were analyzed regarding distinct patient characteristics. Results: Data of 883 patients (children, adolescents, and adults) were analyzed. The highest-ranked patient needs referred to having less AR-symptoms, being able to go outdoors, and being free in the choice of leisure activities. Most patients (89.2-94.6%) attained at least minimally relevant benefit. All subgroups reported relevant benefits, with significantly higher scores in some subgroups. Conclusion: Treatment with Oralair was associated with considerable patient-relevant benefit in all age groups.

Decrease in CD38+ TH2A cell frequencies following immunotherapy with house dust mite tablet correlates with humoral responses

BACKGROUND

In line with evidence for a role of pathogenic TH2A in seasonal allergies, we previously showed that individuals suffering from food allergy exhibited a decrease in circulating TH2A cells following multi-food immunotherapy. Herein, we aim to confirm the decline of TH2A cells in individuals undergoing house dust mite immunotherapy (HDM-AIT) and extend our observation to a new subset of CD38 expressing activated TH2A cells.

METHODS

The frequencies of TH2A and CD38⁺ TH2A cells were analysed by flow cytometry in blood cells from 182 Japanese HDM-allergic individuals included in a 1-year clinical trial assessing the efficacy of HDM tablets. Interrelationship between these cellular responses and humoral mite-specific IgE and IgG4 levels was further explored.

RESULTS

A decrease in TH2A cells was observed in both active and placebo groups. Interestingly, CD38⁺ TH2A cell frequencies significantly decreased only in active groups. In younger individuals (16-30 years), both TH2A and CD38⁺ TH2A cells were significantly reduced in active groups but not in the placebo group. Significant inverse correlations were observed in the course of HDM-AIT between changes in TH2A or CD38⁺ TH2A frequencies and IgG4 antibody levels.

CONCLUSIONS

We confirm the value of monitoring TH2A cell frequencies in allergic individuals and extend this observation to perennial allergy to HDM. We highlight the interest of CD38 to better identify the subset of TH2A cell down-regulated by AIT. Finally, correlated cellular and humoral responses observed in immunoreactive individuals stress that coordinated pathways occur in the adaptive responses during AIT.

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.

Immunological Responses and Biomarkers for Allergen-Specific Immunotherapy Against Inhaled Allergens

Long-term efficacy that occurs with allergen immunotherapy of proven value is associated with decreases in IgE-dependent activation of mast cells and tissue eosinophilia. This suppression of type 2 immunity is accompanied by early induction of regulatory T cells, immune deviation in favor of T_H1 responses, and induction of local and systemic IgG, IgG₄, and IgA antibodies. These "protective" antibodies can inhibit allergen-IgE complex formation and consequent mast cell triggering and IgE-facilitated T_H2-cell activation. Recent studies have highlighted the importance of innate responses mediated by type 2 dendritic cells and innate lymphoid cells in allergic inflammation. These cell types are under the regulation of cytokines such as thymic stromal lymphopoietin and IL-33 derived from the respiratory epithelium. Novel subsets of regulatory cells induced by immunotherapy include IL-35-producing regulatory T cells, regulatory B cells, a subset of T follicular regulatory cells, and IL-10-producing group 2 innate lymphoid cells. These mechanisms point to biomarkers that require testing for their ability to predict clinical response to immunotherapy and to inform novel approaches for better efficacy, safety, and long-term tolerance.

Pharmacoeconomics of allergy immunotherapy versus pharmacotherapy

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

Induction of IL-10-producing type 2 innate lymphoid cells by allergen immunotherapy is associated with clinical response

The role of innate immune cells in allergen immunotherapy that confers immune tolerance to the sensitizing allergen is unclear. Here, we report a role of interleukin-10-producing type 2 innate lymphoid cells (IL-10⁺ ILC2s) in modulating grass-pollen allergy. We demonstrate that KLRG1⁺ but not KLRG1^- ILC2 produced IL-10 upon activation with IL-33 and retinoic acid. These cells attenuated Th responses and maintained epithelial cell integrity. IL-10⁺ KLRG1⁺ ILC2s were lower in patients with grass-pollen allergy when compared to healthy subjects. In a prospective, double-blind, placebo-controlled trial, we demonstrated that the competence of ILC2 to produce IL-10 was restored in patients who received grass-pollen sublingual immunotherapy. The underpinning mechanisms were associated with the modification of retinol metabolic pathway, cytokine-cytokine receptor interaction, and JAK-STAT signaling pathways in the ILCs. Altogether, our findings underscore the contribution of IL-10⁺ ILC2s in the disease-modifying effect by allergen immunotherapy.

Long-term treatment of Japanese cedar pollinosis with Japanese cedar pollen SLIT drops and persistence of treatment effect: A post-marketing clinical trial

BACKGROUND

There have been no reports of treatment effect persistence after long-term sublingual immunotherapy (SLIT) in patients with Japanese cedar (JC) pollinosis. Therefore, we conducted a post-marketing clinical trial to investigate the efficacy, safety, and effect persistence of JC pollen SLIT drops after approximately 3 years of treatment.

METHODS

This was an open-label trial of 233 patients with JC pollinosis who were treated with JC pollen SLIT drops for approximately 3 years (2015-2017) and followed-up for an additional 2 years (2018-2019). Efficacy and effect persistence were evaluated using nasal and ocular symptom scores, daily use of rescue medication, and Japanese Rhinoconjunctivitis Quality of Life Questionnaire scores recorded during the JC pollen dispersal season of each year. Safety was evaluated by monitoring adverse events and adverse drug reactions.

RESULTS

The mean combined total nasal symptom and medication score (range 0-18) during the peak symptom periods of 2015 through 2019 were 5.47 ± 3.38, 4.52 ± 3.13, 3.58 ± 2.63, 5.28 ± 4.01, and 6.83 ± 4.65, respectively. The percentage of patients who used no rescue medications during the same periods was 64.8%, 75.2%, 80.3%, 63.7%, and 50.3%, respectively. A total of 138 adverse drug reaction incidents were recorded in 73 of the 233 patients (31.3%), of which 134 incidents (97.1%) were mild in severity.

CONCLUSIONS

JC pollen SLIT drops demonstrated treatment duration-dependent efficacy with effects that persisted for 2 years after cessation of treatment. The drug had a favorable safety profile over the 5-year study period.

Efficacy of sublingual immunotherapy tablets in dust mite and pollen allergy

The latest evidence on the mechanisms, efficacy, and safety of sublingual immunotherapy (SLIT) was reviewed. Interleukin (IL) 35 and IL-35-producing regulatory T cells were assessed as new biomarkers for SLIT responsiveness. A detailed analysis of clinical studies, including timothy grass pollen, 5-grass pollen, ragweed, and house-dust mite SLIT tablets, was provided, including a comparative analysis of efficacy and safety of SLIT versus subcutaneous immunotherapy.

The evolution of allergy immunotherapy

OBJECTIVE

The objective of this review is to trace the evolution of the art and science of allergy immunotherapy (AIT).

DATA SOURCES

Original reports relating to the evolution of the concept of respiratory allergy and its specific treatment were identified by following references in journal articles, review articles, and allergy textbooks from the mid-20th century to the present.

STUDY SELECTIONS

Studies highlighting substantial milestones in the evolution of the practice of allergy immunotherapy were included.

RESULTS

The story of AIT begins with the recognition of hay fever as a distinct entity and subsequent studies that established grass pollen as one of the causes. This knowledge led several investigators, most notable Leonard Noon and John Freeman who worked at St. Mary's Hospital in London, to attempt to induce tolerance giving grass pollen extract by injection to their patients. After the publication of the work of Noon and Freeman in 1911, the practice of AIT spread rapidly and was applied to many other pollen allergens besides grass and for perennial rhinitis and asthma. The early studies were largely anecdotal, but over the past 60 to 70 years, studies of AIT have been conducted with increasingly sophisticated scientific methods. Nowadays, not only is the practice of AIT based on carefully conducted studies, but the underlying immunologic basis of allergy and the response to AIT have also been and still are being firmly established.

CONCLUSION

Both the art and the science behind the practice of AIT have been established by a solid base of clinical and immunologic studies.

Cost-effectiveness of grass pollen allergen immunotherapy in adults

BACKGROUND

Major scientific societies, such as the EAACI or the AAAAI, do not express any suggestion on which form of allergen immunotherapy (AIT) is to be preferred (subcutaneous immunotherapy, SCIT, vs sublingual immunotherapy, SLIT). This choice could depend on their relative pharmacoeconomic value.

OBJECTIVE

To assess the cost-effectiveness of AIT for grass pollen, administered as SCIT or SLIT.

METHODS

We created a Markovian Model, to evaluate, in a hypothetical cohort of adult patients suffering from moderate-to-severe rhino-conjunctivitis with or without allergic asthma, the cost-effectiveness of SLIT (tablets, Grazax^® and Oralair^® ) or SCIT (various currently available products, plus indirect nonmedical costs, such as travel and productivity costs) in addition to pharmacological therapy, assuming a 9-year horizon to capture AIT long-term effects. The incremental cost-effectiveness ratio (ICER) was calculated assuming pharmacological therapy as the reference comparator.

RESULTS

In the base case, SCIT was slightly more expensive, but more effective than SLIT, being the most cost-effective option (ICER for SCIT, €11 418; ICER for SLIT, €15 212). ICERs greater than €120 000 for both SCIT and SLIT were demonstrated in a scenario assuming that low treatment persistence rates, which are common in real-life, lead to absence of long-term AIT clinical benefit. Considering indirect nonmedical costs SLIT resulted more cost-effective than SCIT (ICER for SCIT, €17 318; ICER for SLIT, €15 212).

CONCLUSION

In daily practice, AIT for grass pollens may be a cost-effective option only in patients with low discontinuation rates. SCIT, which is less affected by this limitation than SLIT, seems the most cost-effective AIT form.

Sublingual Versus Subcutaneous Immunotherapy for Allergic Rhinitis: What Are the Important Therapeutic and Real-World Considerations?

PURPOSE OF REVIEW

Allergen immunotherapy has been used for over 100 years in the treatment of allergic rhinitis. With two major options for administering this disease-modifying therapy, SCIT, and SLIT, what is our current understanding of the efficacy and safety of each one? How do we determine who is the appropriate candidate for each one in the real world?

RECENT FINDINGS

SCIT and SLIT show significant improvement in clinical symptoms and need for medication in the treatment of allergic rhinitis. In recent meta-analyses, there is no significant difference in the efficacy between the two treatments, but SLIT has more local side effects though less systemic ones. Shared decision-making should be instituted to determine which treatment should be started in a patient with allergic rhinitis. This review provides up-to-date information on the efficacy and safety of SCIT vs SLIT in the care of children and adults with allergic rhinitis in the real world and the role of shared decision-making in the use of these modalities.

TRIAL REGISTRATIONS

Clinicaltrials.gov: NCT04145219 and NCT02478398.

EAACI Allergen Immunotherapy User's Guide

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

Mechanisms of allergen-specific immunotherapy for allergic rhinitis and food allergies

Allergen-specific immunotherapy (AIT) is currently the only potential treatment for allergies including allergic rhinitis (AR) and food allergies (FA) that can modify the underlying course of the diseases. Although AIT has been performed for over a century, the precise and detailed mechanism for AIT is still unclear. Previous clinical trials have reported that successful AIT induces the reinstatement of tolerance against the specific allergen. In this review, we aim to provide an updated summary of the knowledge on the underlying mechanisms of IgE-mediated AR and FA as well as the immunological changes observed after AIT and discuss on how better understanding of these can lead to possible identification of biomarkers and novel strategies for AIT.

A Comparison of the Bacterial Nasal Microbiome in Allergic Rhinitis Patients Before and After Immunotherapy

OBJECTIVES/HYPOTHESIS

Recent research has examined the nasal microbiome in rhinosinusitis and nondiseased states. Given immunologic alterations in allergic rhinitis (AR) and after allergen immunotherapy (IT), we evaluated the nasal microbiome in these conditions.

STUDY DESIGN

Cross-sectional comparison.

METHODS

In this cross-sectional study, nasal swabs for microbiome analysis were collected from three patient groups: IT-naïve AR patients, AR patients undergoing IT for greater than 12 months, and a control group without sinonasal inflammatory disease.

RESULTS

Nasal swabs were successfully collected for 14 IT-naïve AR patients, 20 post-IT patients, and 17 controls. The α diversity showed a statistical difference in evenness but not in richness amongst samples, whereas the β-diversity was significantly different between groups. Corynebacterium and Staphylococcus were the most prevalent bacteria across all groups.

CONCLUSIONS

β-diversity was found to be significantly different across the three groups, but the AR groups were found to be more similar to each other than to the controls. Although there is symptomatic improvement in the AR group undergoing IT, the microbiome does not appear to transition to a healthy microbiome composition.

LEVEL OF EVIDENCE

4 Laryngoscope, 2020.

Safety of Timothy Grass Sublingual Immunotherapy Tablet in Children: Pooled Analyses of Clinical Trials

BACKGROUND

Timothy grass sublingual immunotherapy (SLIT) tablets are indicated for children with allergic rhinitis with or without conjunctivitis.

OBJECTIVE

To use pooled analyses to assess the short- and long-term tolerability and safety of timothy grass SLIT-tablet in children.

METHODS

Data from 9 double-blinded, randomized European or North American trials that included children with allergic rhinitis with or without conjunctivitis treated up to 3 years with once-daily timothy grass SLIT-tablet or placebo were pooled.

RESULTS

In all, 1818 (timothy grass SLIT-tablet, n = 923; placebo, n = 895) subjects were included in the analysis. The frequency of treatment-emergent adverse events (AEs) was 86% in the SLIT-tablet group and 83% in the placebo group, and the frequency of treatment-related AEs (TRAEs) was 59% and 23%, respectively. Most (98%) TRAEs were mild to moderate in severity. The 2 most common TRAEs with SLIT-tablet were oral pruritus (33%) and throat irritation (19%), which had a median onset of 1 day and recurrence of 14.5 and 5 days, respectively. In all, 8% of subjects in the SLIT-tablet group and 2% in the placebo group discontinued because of AEs. There were 7 serious AEs assessed as related to SLIT-tablet, 1 systemic allergic reaction (severe with a drop in blood pressure), 3 epinephrine administrations, no eosinophilic esophagitis events, and no serious airway obstructions. The safety profile was similar in subjects across geographic regions and with and without asthma.

CONCLUSIONS

Pooled data indicate that short- and long-term timothy grass SLIT-tablet is well tolerated in children, regardless of geographic region. AEs were generally local, mild, and transient allergic reactions.

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.

Treatment duration-dependent efficacy of Japanese cedar pollen sublingual immunotherapy: Evaluation of a phase II/III trial over three pollen dispersal seasons

BACKGROUND

We conducted a randomized, placebo-controlled, double-blind clinical trial to investigate the optimal dose and long-term efficacy and safety of Japanese cedar (JC) pollen tablets for SLIT (JapicCTI-142579). Here, we report details of the effects of the JC pollen SLIT tablet on rhinitis and conjunctivitis symptoms over three pollen dispersal seasons.

METHODS

A total of 1042 JC pollinosis patients (aged 5-64 years) were randomized to receive tablets containing placebo (P), 2000, 5000, or 10,000 Japanese allergy units (JAU) of JC pollen for 15 months to identify an optimal dose. Patients receiving P (n = 240) and the optimal dose (5000 JAU; A, n = 236) were then randomized to receive P or A for an additional 18 months (AA, AP, PA, and PP groups, allocation ratio 2:1:1:2). Nasal and ocular symptoms, rescue medication use, and quality of life (QOL) were assessed on quantitative scales.

RESULTS

In the second and third seasons, the AA, AP, and PA groups exhibited significantly better improvements in nasal, ocular, and medication scores compared with the PP group in the order AA > AP > PA > PP during the second season and AA > PA > AP > PP during the third season. Rescue medication use and QOL scores were also significantly better in the AA, AP, and PA groups compared with the PP group.

CONCLUSIONS

The JC pollen SLIT tablet relieved nasal and ocular symptoms and medication use and improved QOL in a treatment duration-dependent manner. Continuous dosing regimens appear to enhance the efficacy of the drug.

Clinical efficacy of sublingual immunotherapy tablets for allergic rhinitis is unlikely to be derived from in vitro allergen-release data

Introduction: Allergen bioavailability underpins the efficacy and safety of SLIT tablets. Three product-related factors are likely to influence this: tablet potency, formulation and sublingual holding time. Areas covered: Tablet formulation determines the rate and extent of solubilized allergen release. Using validated in vitro dissolution assays, the two licensed grass pollen SLIT tablets are shown to release ≥85% of their total allergenic activity within several minutes. Sublingual holding time affects the contact duration between solubilized allergens and sublingual tissue. Maximal uptake of allergens by sublingual tissue requires ~5 minutes, with little uptake occurring within the first minute. A higher potency tablet with longer sublingual holding time would provide higher bioavailability, while faster rates of allergen release in vitro are unlikely to translate to a greater increase in bioavailability. Differences in dissolution times cannot serve as a surrogate of in vivo bioavailability, and are not related to differences in efficacy at the marketed tablet dosages. Rapid in vitro dissolution is likely not a key requirement for inducing a potent immune response. Expert opinion: In vitro dissolution cannot predict the clinical efficacy of SLIT tablets but could be important in immune tolerance and safety. In addition, a discontinuous administration regimen may have benefits for adherence and cost without compromising efficacy.

Long-term effects of allergen sublingual immunotherapy

Introduction

Allergen-specific immunotherapy (AIT) is a crucial therapy for allergic rhinitis. However, the long-term effectiveness of AIT remains to be explored.

Aim

To evaluate clinical and immunological long-term effects of sublingual allergen immunotherapy (SLIT) for common inhalant allergens in elderly patients with allergic rhinitis.

Material and methods

This trial was a prospective follow-up observation of patients with allergic rhinitis who completed SLIT for grass pollen or house dust mites (HDM). After 3 years of SLIT, 115 patients were compared to a placebo group during an additional 5 years of observation. The combined symptom medication score (SMS), quality of life and concentration of IgG₄ for Phleum pratense or Dermatophagoides pteronyssinus were monitored during the study.

Results

Five years after SLIT was discontinued, a significant clinical effect based on SMS was still observed compared with the baseline, just after SLIT and 5 years later as follows: 7.53 ±2.09 vs. 2.45 ±0.72 vs. 3.09 ±1.07 (p < 0.05) for HDM and 8.19 ±2.41 vs. 3.05 ±1.62 vs. 4.47 ±2.31 (p < 0.05) for grass pollen. Quality of life based on the Rhinoconjunctivitis Quality of Life Questionnaire was significantly improved in patients who received SLIT and remained at a good level after 5 years of observation. During the 5 years of observation after SLIT, there were no significant changes between specific IgG₄ levels and the analysed allergens compared to results just after SLIT.

Conclusions

The positive effect obtained after SLIT for grass pollen or house dust mites was sustained for a long period after AIT.

Shortened up-dosing with sublingual immunotherapy drops containing tree allergens is well tolerated and elicits dose-dependent clinical effects during the first pollen season

Background

This study compared a rapid home-based up-dosing schedule for sublingual immunotherapy (SLIT) drops containing tree pollen allergens with two previously established schedules. Furthermore, the clinical effect of the SLIT was investigated with respect to patients’ first pollen season under treatment.

Methods

In this open-label, prospective, patient-preference, non-interventional study, local and systemic reactions were compared between three up-dosing groups using a SLIT formulation containing birch, alder, and hazel pollen extracts (ORALVAC^® Compact Bäume). Clinical improvement after patients’ first season under treatment was analysed using symptom scores, ARIA classification, symptom control, and the use of symptomatic medication and was compared with data from the previous, pre-treatment pollen season. As the real-life study design allowed no placebo group, the late-treated patients (co-seasonal) served as a control, and crowd-sourced symptom data from persons with hay fever were used from a free web-based online diary.

Results

In 33 study centres in Germany and Austria, 164 patients were included. The treatment was well tolerated, without difference between the groups during the up-dosing phase. At the end of the assessment, 96.1% rated the tolerability of the treatment as good or very good. Local reactions were mostly mild in severity and no serious adverse events occurred. Symptom scores decreased from the 2016 pollen season to the 2017 pollen season. As for the ARIA classification, 79.0% of patients had persistent, moderate-to-severe rhinitis before treatment, but only 18.6% had the same classification after treatment. In all, 62.4% of patients achieved symptom control, and 34.3% of patients required no symptomatic medication after treatment. The rhinoconjunctivitis score was 34.4% lower for pre-seasonal treatment initiation than for the control group. Crowd-sourced symptom load indices showed that the 2016 season caused slightly more symptoms; however, it is assumed that this difference of 0.3–0.5 (score range 0–10) was of less clinical relevance.

Conclusion

The treatment administered using the rapid home-based up-dosing schedule was safe and well tolerated. Symptom relief and reduction in medication use were observed during the first pollen season with SLIT.

Trial registration number

NCT03097432 (clinicaltrials.gov).

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.

Prolonged effect of allergen sublingual immunotherapy to grass pollen

Background: The prolonged effect of allergen immunotherapy is unknown, especially in older patients. Objective: The three-year effect of sublingual allergen-specific immunotherapy (AIT) to grass pollen on elderly patients with allergic rhinitis was analyzed. Methods: Thirty-eight elderly patients (63.18 ± 3.12 yrs.) underwent AIT to grass pollen, were monitored for three years and were compared to a placebo group. AIT was performed with the use of an oral Staloral 300 SR grass extract (Stallergens Greer, London, UK) or a placebo. Symptoms and medication scores, represented by the average adjusted symptom score (AAdSS), the serum level of IgG4 to Phl p5 and the quality of life were assessed immediately after AIT and three years later. Results: After AIT, the AAdSS was significantly decreased and remained lower than in the placebo group during the three years after AIT. Serum-specific IgG4 against Phl p5 increased during the AIT trial in the study group. For the three years of observation after AIT, there were no significant changes in specific IgG4 levels against the analyzed allergens in comparison to the results immediately after AIT. The quality of life, based on the Rhinoconjunctivitis Quality of Life Questionnaire, was significantly decreased in patients who received AIT, from 1.83 (95%CI: 1.45-1.96) to 0.74 (95%CI: 0.39-1.92) (p < 0.05) to 0.82 (95%CI: 0.45- 1.04) three years after AIT. Conclusion: A prolonged positive effect after AIT to grass pollen was observed in elderly patients with allergic rhinitis. Further trials are needed to confirm this effect.

Short course of grass allergen peptides immunotherapy over 3 weeks reduces seasonal symptoms in allergic rhinoconjunctivitis with/without asthma: A randomized, multicenter, double-blind, placebo-controlled trial

Background

Immunotherapy with peptide hydrolysates from Lolium perenne (LPP) is an alternative treatment for seasonal allergic rhinitis with or without asthma. The aim of this study was to assess the clinical efficacy and safety of a cumulative dose of 170 μg LPP administered subcutaneously over 3 weeks.

Methods

In a randomized, double‐blind, placebo‐controlled trial, 554 adults with grass pollen rhinoconjunctivitis were randomized (1:2 ratio) to receive 8 subcutaneous injections of placebo or 170 μg LPP administered in increasing doses in 4 visits over 3 weeks. The primary outcome was the combined symptom and medication score (CSMS) measured over the peak pollen season. Reactivity to conjunctival provocation test (CPT) and quality of life (QOL) was assessed as secondary endpoints.

Results

The mean reduction in CSMS in the LPP vs placebo group was −15.5% (P = .041) during the peak period and −17.9% (P = .029) over the entire pollen season. LPP‐treated group had a reduced reactivity to CPT (P < .001) and, during the pollen season, a lower rhinoconjunctivitis QOL global score (P = .005) compared with placebo group. Mostly mild and WAO grade 1 early systemic reaction (ESR) were observed ≤30 minutes in 10.5% of LPP‐treated patients, whereas 3 patients with a medical history of asthma (<1%) experienced a serious ESR that resolved with rescue medication.

Conclusion

Lolium perenne pollen peptides administered over 3 weeks before the grass pollen season significantly reduced seasonal symptoms and was generally safe and well‐tolerated.

Duration of Allergen Immunotherapy for Long-Term Efficacy in Allergic Rhinoconjunctivitis

RATIONALE

Subcutaneous and sublingual immunotherapy are effective for allergic rhinitis. An important question is whether allergen immunotherapy provides a sustained clinical effect after treatment cessation. In view of potential side effects, cost and the necessary patient commitment, long-term benefit is an important consideration for the recommendation of immunotherapy over standard pharmacotherapy.

PURPOSE OF REVIEW

In this review, we analyse the existing evidence for long-term effects of both routes of administration in the context of double-blind, placebo-controlled, randomised clinical trials that included a follow-up phase of at least 1 year after treatment cessation.

RECENT FINDINGS

Overall, evidence suggests that 3 years of either subcutaneous or sublingual immunotherapy result in clinical benefit and immunological changes consistent with allergen-specific tolerance sustained for at least 2-3 years after treatment cessation.

SUMMARY

The data presented here support recommendations in international guidelines that both routes of administration should be continued for a minimum of 3 years. Gaps in the evidence remain regarding the long-term efficacy of immunotherapy for perennial rhinitis and studies performed in children.