Regulatory aspects of allergen-specific immunotherapy: europe sets the scene for a global approach

Transition between subcutaneous and sublingual allergen immunotherapy: Recommendations of the Brazilian Association of Allergy and Immunology (ASBAI)

The use of allergen immunotherapy (AIT) in Brazil has specific regional conditions owing to the pattern of allergen sensitization, as well as to genetic, socioeconomic, and cultural characteristics. This review article aims to discuss the clinical practice of AIT by the subcutaneous or sublingual route in Brazil, addressing the possibilities of transition between these forms of administration. A systematic review using the PubMed and Cochrane databases was performed, and the websites of major allergy and immunology organizations were consulted. Knowledge of the mechanism of action of subcutaneous immunotherapy and sublingual immunotherapy, together with Brazilian real-life experience, allowed us to establish recommendations regarding switching routes of AIT administration in selected cases. Careful analysis of each clinical situation is necessary to perform the transition between subcutaneous and sublingual allergen immunotherapy.

Immunotherapies in the treatment of immunoglobulin E‑mediated allergy: Challenges and scope for innovation (Review)

Immunoglobulin E (IgE)‑mediated allergy or hypersensitivity reactions are generally defined as an unwanted severe symptomatic immunological reaction that occurs due to shattered or untrained peripheral tolerance of the immune system. Allergen‑specific immunotherapy (AIT) is the only therapeutic strategy that can provide a longer‑lasting symptomatic and clinical break from medications in IgE‑mediated allergy. Immunotherapies against allergic diseases comprise a successive increasing dose of allergen, which helps in developing the immune tolerance against the allergen. AITs exerttheirspecial effectiveness directly or indirectly by modulating the regulator and effector components of the immune system. The number of success stories of AIT is still limited and it canoccasionallyhave a severe treatment‑associated adverse effect on patients. Therefore, the formulation used for AIT should be appropriate and effective. The present review describes the chronological evolution of AIT, and provides a comparative account of the merits and demerits of different AITs by keeping in focus the critical guiding factors, such as sustained allergen tolerance, duration of AIT, probability of mild to severe allergic reactions and dose of allergen required to effectuate an effective AIT. The mechanisms by which regulatory T cells suppress allergen‑specific effector T cells and how loss of natural tolerance against innocuous proteins induces allergy are reviewed. The present review highlights the major AIT bottlenecks and the importantregulatory requirements for standardized AIT formulations. Furthermore, the present reviewcalls attention to the problem of 'polyallergy', which is still a major challenge for AIT and the emerging concept of 'component‑resolved diagnosis' (CRD) to address the issue. Finally, a prospective strategy for upgrading CRD to the next dimension is provided, and a potential technology for delivering thoroughly standardized AIT with minimal risk is discussed.

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.

Recombinant Allergens in Structural Biology, Diagnosis, and Immunotherapy

The years 1988-1995 witnessed the beginning of allergen cloning and the generation of recombinant allergens, which opened up new avenues for the diagnosis and research of human allergic diseases. Most crystal and solution structures of allergens have been obtained using recombinant allergens. Structural information on allergens allows insights into their evolutionary biology, illustrates clinically observed cross-reactivities, and makes the design of hypoallergenic derivatives for allergy vaccines possible. Recombinant allergens are widely used in molecule-based allergy diagnosis such as protein microarrays or suspension arrays. Recombinant technologies have been used to produce well-characterized, noncontaminated vaccine components with known biological activities including a variety of allergen derivatives with reduced IgE reactivity. Such recombinant hypoallergens as well as wild-type recombinant allergens have been used successfully in several immunotherapy trials for more than a decade to treat birch and grass pollen allergy. As a more recent application, the development of antibody repertoires directed against conformational epitopes during immunotherapy has been monitored by recombinant allergen chimeras. Although much progress has been made, the number and quality of recombinant allergens will undoubtedly increase and keep improving our knowledge in basic scientific investigations, diagnosis, and therapy of human allergic diseases.

Clinical practice recommendations for allergen-specific immunotherapy in children: the Italian consensus report

Allergen-specific immunotherapy (AIT) is currently recognized as a clinically effective treatment for allergic diseases, with a unique disease-modifying effect. AIT was introduced in clinical practice one century ago, and performed in the early years with allergenic extracts of poor quality and definition. After the mechanism of allergic reaction were recognized, the practice of AIT was refined, leading to remarkable improvement in the efficacy and safety profile of the treatment. Currently AIT is accepted and routinely prescribed worldwide for respiratory allergies and hymenoptera venom allergy. Both the subcutaneous (SCIT) and sublingual (SLIT) routes of administration are used in the pediatric population.AIT is recommended in allergic rhinitis/conjunctivitis with/without allergic asthma, with an evidence of specific IgE-sensitization towards clinically relevant inhalant allergens. Long-term studies provided evidence that AIT can also prevent the onset of asthma and of new sensitizations. The favorable response to AIT is strictly linked to adherence to treatment, that lasts 3-5 years. Therefore, several factors should be carefully evaluated before starting this intervention, including the severity of symptoms, pharmacotherapy requirements and children and caregivers' preference and compliance.In recent years, there have been increasing interest in the role of AIT for the treatment of IgE-associated food allergy and extrinsic atopic dermatitis. A growing body of evidence shows that oral immunotherapy represents a promising treatment option for IgE-associated food allergy. On the contrary, there are still controversies on the effectiveness of AIT for patients with atopic dermatitis.This consensus document was promoted by the Italian Society of Pediatric Allergy and Immunology (SIAIP) to provide evidence-based recommendations on AIT in order to implement and optimize current prescription practices of this treatment for allergic children.

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

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

International Consensus on Allergen Immunotherapy II: Mechanisms, standardization, and pharmacoeconomics

This article continues the comprehensive international consensus (ICON) statement on allergen immunotherapy (AIT). The initial article also recently appeared in the Journal. The conclusions below focus on key mechanisms of AIT-triggered tolerance, requirements in allergen standardization, AIT cost-effectiveness, and regulatory guidance. Potential barriers to and facilitators of the use of AIT are described in addition to future directions. International allergy specialists representing the European Academy of Allergy and Clinical Immunology; the American Academy of Allergy, Asthma & Immunology; the American College of Allergy, Asthma and Immunology; and the World Allergy Organization critically reviewed the existing literature and prepared this summary of recommendations for best AIT practice. The authors contributed equally and reached consensus on the statements presented herein.

Comparison of allergenic extracts from different origins: the value of the FDA's bioequivalent allergy unit (BAU)

INTRODUCTION

Allergy immunotherapy (AIT) is the only disease-modifying intervention for the treatment of allergic diseases. The clinical effectiveness of AIT is clearly dose-dependent, so it is important that clinicians can assess and compare the potency of the various products available. However, this is not possible in practice, because manufacturers use different methods to determine potency. Therefore, a clear need exists for adoption of a 'gold-standard' measure of allergenicity. The bioequivalent allergy unit (BAU) is thus far the only allergen unit approved by a regulatory agency (the US Food and Drug Administration), with European regulatory authorities yet to adopt a common unit.

AREAS COVERED

Using PubMed, we performed a review of the literature on measures of allergen extract potency, use of the BAU, and BAU assessment for grass pollen tablets. Expert commentary: There is an obvious benefit to allergists and patients for having a single, comparable unit across products, and we strongly support the adoption of a single, 'gold-standard' unit of measurement for all products. Use of the BAU allows a clear comparison of the potency of allergen products from different manufacturers, and enables better understanding of the potential reasons for any differences in administration and dosing protocols between these products.

Update on immunotherapy for the treatment of asthma

PURPOSE OF REVIEW

Despite that specific immunotherapy can boast being more than a century old, there is still skepticism about its real effectiveness, and therefore it is still used too little in clinical practice. The purpose of this review was to analyze the most recent articles in the literature to highlight scientific evidence for the proper use of allergen immunotherapy (AIT).

RECENT FINDINGS

In the near future, the concept of medicine for trials will have to be revised and in certain cases abandoned in favor of a personalized medicine, able to use a drug more targeted for the individual patient and not for the disease.

SUMMARY

For AIT, it will become increasingly important to use products designed properly, standardized and with a well documented effectiveness in clinical studies. We must overcome the disputes of subcutaneous immunotherapy versus sublingual immunotherapy, arrive at the concept of personalized medicine regarding AIT, framing in different phenotypes of asthma patients to use the optimal preparation for each particular patient.

Choosing the optimal dose in sublingual immunotherapy: Rationale for the 300 index of reactivity dose

Sublingual immunotherapy (SLIT) is an effective and well-tolerated method of treating allergic respiratory diseases associated with seasonal and perennial allergens. In contrast to the subcutaneous route, SLIT requires a much greater amount of antigen to achieve a clinical effect. Many studies have shown that SLIT involves a dose–response relationship, and therefore it is important to use a proven clinically effective dose from the onset of treatment, because low doses are ineffective and very high doses may increase the risk of side effects. A well-defined standardization of allergen content is also crucial to ensure consistent quality, potency and appropriate immunomodulatory action of the SLIT product. Several methods of measuring antigenicity are used by manufacturers of SLIT products, including the index of reactivity (IR), standardized quality tablet unit, and bioequivalent allergy unit. A large body of evidence has established the 300 IR dose of SLIT as offering optimal efficacy and tolerability for allergic rhinitis due to grass and birch pollen and HDM, and HDM-induced moderate, persistent allergic asthma. The 300 IR dose also offers consistency of dosing across a variety of different allergens, and is associated with higher rates of adherence and patient satisfaction. Studies in patients with grass pollen allergies showed that the 300 IR dose has a rapid onset of action, is effective in both adults and children in the short term and, when administered pre-coseasonally in the long term, and maintains the clinical benefit, even after cessation of treatment. In patients with HDM-associated AR and/or asthma, the 300 IR dose also demonstrated significant improvements in symptoms and quality of life, and significantly decreased use of symptomatic medication. The 300 IR dose is well tolerated, with adverse events generally being of mild or moderate severity, declining in frequency and severity over time and in the subsequent courses. We discuss herein the most important factors that affect the selection of the optimal dose of SLIT with natural allergens, and review the rationale and evidence supporting the use of the 300 IR dose.

Allergen Immunotherapy: History and Future Developments

Allergen immunotherapy (AIT) was introduced in clinical practice more than 100 years ago. The clinical effectiveness in allergic rhinitis (and asthma) and in hymenoptera allergy was apparent early on but it was not until the mid-1900s that randomized placebo-controlled trials proved its efficacy. In the 1980s, sublingual immunotherapy (SLIT) was accepted in official guidelines. The availability of safer routes, such as SLIT, prompted increasing investigation of AIT for food allergy. The introduction of molecular-based diagnosis introduced the possibility of better targeted prescription of AIT. Other approaches are being explored, such as immunogenic peptides, recombinant allergens, and adjuvants.

AIT (allergen immunotherapy): a model for the "precision medicine"

The interpretation of medical approaches, especially therapy, evolved rapidly in the last century. Starting from the simple description of symptoms, we moved to the pathophysiological descriptions, to the evidence-based medicine, until the so-called "precision medicine". This latter can be defined as a structural model aimed at customizing healthcare, with medical decisions/products tailored on an individual patient at a highly detailed level. In this sense, allergen immunotherapy represents an optimal model of "precision medicine", since we know and describe symptoms, function, aetiological agents at molecular level, and we have the possibility to intervene on the natural history of the disease. If considered under the point of view of pharmaco-economy, that is prescribing the optimal treatment to the right patient, allergen immunotherapy represents an almost-ideal model of precision medicine.

Allergen immunotherapy on the way to product-based evaluation-a WAO statement

Allergen immunotherapy (AIT) is widely used in clinical practice for patients with moderate to severe allergic rhinitis due to inhalant allergens and may be delivered via subcutaneous (SCIT) and sublingual routes (SLIT). However, the quality of evidence for individual AIT products is very heterogeneous, and extensions of overall conclusions ("class effects") on the efficacy and disease-modifying effects to all AIT products are unjustified. In contrast, each product needs to be evaluated individually, based on available study results, to justify efficacy and specific claims on sustained and disease modifying effects per allergen and targeted patient group (children vs. adults, allergic rhinitis vs. asthma). WAO intends to support the current development to evidence-based AIT, which ultimately will lead to a more efficacious treatment of allergic patients and the appropriate recognition of AIT.

Respiratory allergies: a general overview of remedies, delivery systems, and the need to progress

The spread of respiratory allergies is increasing in parallel with the alarm of the scientific community. Evidently, our knowledge of the onset mechanisms of these diseases and, as a consequence, of the available remedies is inadequate. This review provides a brief, general description of current therapeutic resources and the state of research with regard to both drugs and medical devices in order to highlight their limits and the urgent need for progress. Increasing the amount of basic biochemical research will improve our knowledge of such onset mechanisms and the potential efficacy of therapeutic preparations.