Dose-response relationship of a new Timothy grass pollen allergoid in comparison with a 6-grass pollen allergoid

Focused allergic rhinitis practice parameter for Canada

Allergic rhinitis (AR) is a prevalent disease in Canada that affects both children and adults. Several guidelines for the management of AR have been published by professional allergy societies worldwide. However, there are regional differences in the clinical management of AR, and regulatory approval of some AR pharmacotherapies varies among countries. Thus, six research questions specific to the treatment of AR in Canada were identified for this focused practice parameter. Reviews of the literature published since 2016 were conducted to obtain evidence-based support for the responses of the Work Group to each research question. In response to research question 1 "In patients with symptoms indicative of AR, is serum-specific IgE sufficient to identify candidates for immunotherapy or is a skin prick test mandatory?" the Work Group concluded that either sIgE testing or skin prick test are acceptable for diagnosing AR and guiding immunotherapy. In response to research question 2 "When taking into account the preferences of the patient and the prescriber (stakeholder engagement) should second-generation oral antihistamine (OAH) or intranasal corticosteroid (INCS) be first line?" the Work Group concluded that existing guidelines generally agree on the use of INCS as a first-line therapy used for AR, however, patient and provider preferences and considerations can easily shift the first choice to a second-generation OAH. In response to research question 3 "Is a combination intranasal antihistamine (INAH)/INCS formulation superior to INCS plus OAH? Do they become equivalent after prolonged use?" the Work Group concluded that that the combination INAH/INCS is superior to an INCS plus OAH. However, there was insufficient evidence to answer the second question. In response to research question 4 "Do leukotriene receptor antagonists (LTRA) have a greater benefit than OAH in AR for some symptoms to justify a therapeutic trial in those who cannot tolerate INCS?" the Work Group concluded that LTRAs have inferior, or at best equivalent, daytime or overall symptom control compared with OAH, but LTRAs may improve nighttime symptom control and provide benefits in patients with AR and concomitant asthma. In response to research question 5 "Should sublingual immunotherapy (SLIT) tablets be considered first-line immunotherapeutic options over subcutaneous immunotherapy (SCIT) based on the evidence of efficacy?" the Work Group concluded that the choice of SLIT or SCIT cannot be made on efficacy alone, and differences in other factors outweigh any differences in efficacy. In response to research question 6 "Based on efficacy data, should ALL patients seen by an allergist be offered SLIT or SCIT as a treatment option?" the Work Group concluded that the efficacy data suggests that SLIT or SCIT should be used broadly in patients with AR, but other clinical concerns also need to be taken into consideration.

A high-dose, depigmented polymerized birch pollen extract for subcutaneous allergen immunotherapy has a favourable efficacy/safety ratio

BACKGROUND

Subcutaneous allergen immunotherapy (SCIT) with depigmented, polymerized (DPP) birch pollen extract has been marketed at doses of up to 1000 DPP units/mL since 2001. We sought to determine the dose-dependent efficacy of a DPP birch pollen extract formulation in patients suffering from birch-pollen-induced allergic rhinitis or rhinoconjunctivitis with or without intermittent asthma.

METHODS

A titrated conjunctival provocation test (CPT) was applied as a surrogate marker. This Phase II randomized, double-blind, parallel-group, dose-ranging clinical trial was performed at 39 centres in Germany, Lithuania and Poland. After randomization to four dose-level groups (100, 1000, 5000 and 10,000 DPP units/mL) and up-dosing, participants received maintenance SCIT with five monthly subcutaneous injections. The primary endpoint was the proportion of patients in whom a higher concentration of birch pollen (vs. baseline) was needed to elicit a positive CPT.

RESULTS

Three hundred forty-three patients were included (mean (range) age: 42.6 (19-70)). The highest CPT responder rates were seen in the higher dose-level groups. In the intention-to-treat analysis, the difference between the 100 and 10,000 groups was statistically significant (p = 0.0118). Although the proportion of patients with ≥1 treatment-emergent adverse events increased with the dose, almost all these events were mild (65.6%) or moderate (18.5%).

CONCLUSION

Judging by the results of a CPT, the efficacy/safety ratio in SCIT appears to be favourable for a high-dose-level preparation of a DPP birch pollen extract.

Allergen immunotherapy: progress and future outlook

INTRODUCTION

Allergy, the immunological hypersensitivity to innocuous environmental compounds, is a global health problem. The disease triggers, allergens, are mostly proteins contained in various natural sources such as plant pollen, animal dander, dust mites, foods, fungi and insect venoms. Allergies can manifest with a wide range of symptoms in various organs, and be anything from just tedious to life-threatening. A majority of all allergy patients are self-treated with symptom-relieving medicines, while allergen immunotherapy (AIT) is the only causative treatment option.

AREAS COVERED

This review will aim to give an overview of the state-of-the-art allergy management, including the use of new biologics and the application of biomarkers, and a special emphasis and discussion on current research trends in the field of AIT.

EXPERT OPINION

Conventional AIT has proven effective, but the years-long treatment compromises patient compliance. Moreover, AIT is typically not offered in food allergy. Hence, there is a need for new, effective and safe AIT methods. Novel routes of administration (e.g. oral and intralymphatic), hypoallergenic AIT products and more effective adjuvants holds great promise. Most recently, the development of allergen-specific monoclonal antibodies for passive immunotherapy may also allow treatment of patients currently not treated or treatable.

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.

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.

The use of nasal allergen vs allergen exposure chambers to evaluate allergen immunotherapy

INTRODUCTION

Allergen-specific immunotherapy (AIT) is the only disease-modifying treatment option for allergic rhinitis (AR) patients with persistent moderate-severe AR for whom traditional pharmacotherapies are ineffective. The nasal allergen challenge (NAC) and allergen exposure chamber (AEC) are two translational models of AR that can be used to investigate the properties, safety, and efficacy of AIT.

AREAS COVERED

Peer-reviewed, human-centered articles utilizing AEC or NAC models to investigate AIT between 2010 and 2020 were curated from PubMed, EMBASE, and OVID Medline databases. AECs have been used to evaluate traditional subcutaneous and sublingual administrations of AIT, including cross-protective effects and different dosing regimens. More recently, the effectiveness of novel AIT formulations has been evaluated. NACs are another model used to study AIT, including using novel intralymphatic routes of administration. It is an especially powerful and versatile tool to determine if basic science and animal model findings are clinically translatable.

EXPERT OPINION

The AEC and NAC models both produce clinically relevant and reproducible results. AECs are more effective for studying many participants but are limited because they require a specialized facility. As more AIT therapies and new formulations are developed over time, the versatility of the NAC will be especially useful.

Placebo effects in allergen immunotherapy-An EAACI Task Force Position Paper

The placebo (Latin "I will please") effect commonly occurs in clinical trials. The psychological and physiological factors associated with patients' expectations about a treatment's positive and negative effects have yet to be well characterized, although a functional prefrontal cortex and intense bidirectional communication between the central nervous system and the immune system appear to be prerequisites for a placebo effect. The use of placebo raises certain ethical issues, especially if patients in a placebo group are denied an effective treatment for a long period of time. The placebo effect appears to be relatively large (up to 77%, relative to pretreatment scores) in controlled clinical trials of allergen immunotherapy (AIT), such as the pivotal, double-blind, placebo-controlled (DBPC) randomized clinical trials currently required by regulatory authorities worldwide. The European Academy of Allergy and Clinical Immunology (EAACI) therefore initiated a Task Force, in order to better understand the placebo effect in AIT and its specific role in comorbidities, blinding issues, adherence, measurement time points, variability and the natural course of the disease. In this Position Paper, the EAACI Task Force highlights several important topics regarding the placebo effect in AIT such as a) regulatory aspects, b) neuroimmunological and psychological mechanisms, c) placebo effect sizes in AIT trials, d) methodological limitations in AIT trial design and e) potential solutions in future AIT trial design. In conclusion, this Position Paper aims to examine the methodological problem of placebo in AIT from different aspects and also to highlight unmet needs and possible solutions for future trials.

Perspectives in Allergen-Specific Immunotherapy: Molecular Evolution of Peptide- and Protein-Based Strategies

Allergen-specific Immunotherapy (AIT), through repetitive subcutaneous or sublingual administrations of allergen extracts, represents up to now the unique treatment against allergic sensitizations. However, the clinical efficacy of AIT can be largely dependent on the quality of natural allergen extracts. Moreover, the long duration and adverse side effects associated with AIT negatively impact patient adherence. Tremendous progress in the field of molecular allergology has made possible the design of safer, shorter and more effective new immunotherapeutic approaches based on purified and characterized natural or recombinant allergen derivatives and peptides. This review will summarize the characteristics of these different innovative vaccines including their effects in preclinical studies and clinical trials.

Allergen exposure chambers: implementation in clinical trials in allergen immunotherapy

Allergen exposure chambers (AECs) have been developed for controlled allergen challenges of allergic patients mimicking natural exposure. As such, these facilities have been utilized e.g., for proof of concept, dose finding or the demonstration of onset of action and treatment effect sizes of antiallergic medication. Moreover, clinical effects of and immunological mechanisms in allergen immunotherapy (AIT) have been investigated in AECs. In Europe AIT products have to fulfill regulatory requirements for obtaining market authorization through Phase I to III clinical trials. Multiple Phase II (dose-range-finding or proof-of-concept) trials on AIT products have been performed in AECs. However, they are not accepted by regulatory bodies for pivotal (Phase III) trials and a more thorough technical and clinical validation is requested. Recently, a Position Paper of the European Academy of Allergy and Clinical Immunology (EAACI) has outlined unmet needs in further development of AECs. The following review aims to address some of these needs on the basis of recently published data in the first part, whereas the second part overviews published examples of most relevant Phase II trials in AIT performed in AEC facilities.

30 years of sublingual immunotherapy

Allergen Immunotherapy (AIT) was introduced in clinical practice on an empirical basis more than 100 years ago. Since the first attempts, AIT was administered subcutaneously. Indeed, other routes of administration were proposed and studied, in particular to improve the safety, but only the sublingual route (SLIT) achieved a credibility based on evidence and was then accepted as a viable "alternative" option to the subcutaneous route. SLIT was largely used in clinical trials and clinical practice in this last 30 years. Thus, a large amount of data is available, coming from either controlled trials and postmarketing surveillance studies. It is clear that SLIT is overall effective, but it is also clear that the efficacy is not "class-related," as derived from meta-analyses, but restricted to each specific product. The 30-year lasting use of SLIT allowed to clarify many clinical aspects, such as efficacy, safety, use in asthma, regimens of administration, and optimal doses. In parallel, the mechanisms of action of AIT were elucidated, and new indications were proposed (eg food allergy, atopic dermatitis). In addition, the introduction of molecular-based diagnosis, allowed to better refine the prescription of SLIT, based on specific sensitization profiles. The present article will describe the origin and evolution of SLIT for respiratory allergy, taking into account the clinical context that suggested this form of treatment, the recently developed aspects, the future perspectives and unmet needs, This is not, therefore, a systematic review, rather a narrative historical description of the past history, and a look forward to the future opportunities.

Allergen immunotherapy phase II trials: Challenges in dose finding

Phase II studies on allergen immunotherapy (AIT) should define the dose with the best balance between efficacy and safety ("optimal dose"). Their key role is based on dose selection for subsequent pivotal studies (phase III, field studies). Since products for AIT differ in composition and unit definitions, phase II trials are mandatory for new products and preparations being developed according to the German Therapy Allergen Ordinance ("Therapie-Allergeneverordnung", TAV) due to current EMA guidelines since 2009. The latter permit various in-vivo models and endpoints for phase II studies, e.g., AIT-induced changes in skin test, nasal, conjunctival or bronchial provocation, or in exposure chamber or field trials. Selection and graduation of the doses, minimization of placebo effects, and sufficient numbers of patients are a challenge. Effort, required time, and costs are important variables for the initiators of phase II trials. Risks are characterized by e.g., a) too small doses without relevant differences compared to placebo, b) missing true dose-response relationships, c) strong placebo effect and consequently small "therapeutic window", d) large heterogeneity and missing distinct differences (compared to placebo), e) too small effects in field studies due to low allergen exposure, f) missing dose-related increase (in case of too high doses). In the view of the Paul-Ehrlich-Institute, the unambiguous phase II trials with TAV products performed until today were not able to confirm the marketed doses for AIT. Regardless of the utilized model, more raw and single data should illustrate the individual outcome of AIT during phase II trials, facilitating an improved and more intuitive interpretation of the data (placebo effects? scattering?). In the medium term, evidence regarding AIT efficacy will considerably increase due to phase II trials as a prerequisite for subsequent phase III field studies. This affects all manufacturers offering AIT products in Germany and Europe.

Developments in the field of allergy in 2017 through the eyes of Clinical and Experimental Allergy

In this article, we described the development in the field of allergy as described by Clinical and Experimental Allergy in 2017. Experimental models of allergic disease, basic mechanisms, clinical mechanisms, allergens, asthma and rhinitis and clinical allergy are all covered.

Randomized immunotherapy trial in dual-allergic patients using "active allergen placebo" as control

BACKGROUND

Placebo control in allergen immunotherapy (AIT) trials presents ethical and blinding concerns. We tested a trial design with an "active allergen placebo," as proposed by ARIA-GA2 LEN, to investigate in a double-blind trial the efficacy and safety of AIT in dual-allergic patients (grass and birch pollen) using active untargeted treatments as controls.

METHODS

We randomized 95 patients to receive either grass (N = 47) or birch AIT (N = 48). Patients were exposed to both allergens in an allergen challenge chamber (ACC) before and after 9 months of AIT. Targeted (ACC-allergen = AIT-allergen) and untargeted (ACC-allergen ≠ AIT-allergen) treatment effects were assessed.

RESULTS

Immunotherapy reduced significantly the mean (95% confidence interval) area under the curve of total nasal symptom score (targeted effects) by -13.55 (-17.56, -9.54; P < 0.001) after grass and -9.81 (-14.13, -5.50; P < 0.001) after birch AIT. Differences in targeted vs untargeted effects between AIT groups (utility of control group) were statistically significant for both grass (P = 0.02) and birch (P = 0.02) allergens. Targeted vs untargeted differences within-treatment groups (specificity of ACC measurement) were significant for grass AIT (P < 0.001) but not significant for birch AIT group (P = 0.24). Specific immunoglobulin G4 to both allergens increased significantly (P < 0.001) after targeted treatment, while remained unchanged for untargeted treatments. Both treatments were well tolerated.

CONCLUSIONS

Immunotherapies for both grass and birch allergens were efficacious and safe. The study confirms the specificity of AIT. Untargeted treatment groups could serve as controls in future AIT trials.