Allergen Immunotherapy: Clinical Outcomes Assessment

Recent Advances in Allergen-Specific Immunotherapy as Treatment for Allergic Asthma: A Practical Overview

The Global Initiative for Asthma Report updated in 2019 stated that potential benefits of allergen immunotherapy (AIT), compared to pharmacological and avoidance options, must be weighed against the risk of adverse effects and the inconvenience and cost of the prolonged course of therapy in asthma. Thus, with the aim of clarifying some aspects with regard to the possible use of AIT in allergic asthma treatment armamentarium, a group of expert allergists from the Spanish Allergy and Clinical Immunology Scientific Society (SEAIC), particularly from the Immunotherapy and Asthma Interest Groups developed a frequently asked questions in clinical practice. This document updates relevant topics on the use of AIT in asthma and could facilitate physician clinical decisions and improve health outcomes for individual patients.

RCAT reflects symptom control and quality of life in allergic rhinoconjunctivitis patients

BACKGROUND

The Global Allergy and Asthma European Network (GA² LEN) Taskforce has requested more data on correlations between various patient-reported outcomes (PROs) in clinical trials on allergy. We compared three tools-the Rhinitis Control Assessment Test (RCAT), Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and Rhinitis Total Symptom Score (RTSS)-to determine whether the RCAT alone is a sufficient primary outcome parameter in clinical trials on allergic rhinoconjunctivitis.

METHODS

In two double-blind, placebo-controlled immunotherapy studies, 33 patients allergic to grass pollen and 94 to birch pollen completed two questionnaires (RCAT and RQLQ) and kept their own symptom diary from which the RTSS was calculated.

RESULTS

Upon comparing RCAT and RQLQ results, we found strong correlations of r = -0.871 for grass pollen-allergic patients and r = -0.795 for birch pollen-allergic patients. The comparison between RCAT and RTSS results showed a strong correlation of r = -0.811 (grass pollen-allergic patients) and a moderate correlation of r = -0.539 (birch pollen-allergic patients). In the RCAT, 69.7% of grass pollen-allergic patients and 45.7% of birch pollen-allergic patients receiving guideline-concordant therapy were regarded as having insufficiently controlled symptoms.

CONCLUSION

The strong correlations suggest that the RCAT alone is equivalent to the RQLQ with respect to patients' symptom control and quality of life. Patients with uncontrolled symptoms can be identified using the RCAT. Hence, the physician can decide whether symptomatic therapy can be intensified or allergy immunotherapy should be administered.

Tablet-based sublingual immunotherapy for respiratory allergy

Allergic respiratory disease represents a significant and expanding health problem worldwide. The gold standard of therapeutic intervention is still grucocorticosteroids, although they are not effective in all patients and may cause side effects. Allergen Immunotherapy has been administrated as subcutaneous injections for treatment of allergic rhinoconjunctivitis and asthma and has been practiced for the past century. Sublingual immunotherapy (SLIT) tablets are now available for grass- or ragweed-induced rhinoconjunctivitis and will be available in Spain for house dust mite (HDM)-induced rhinoconjunctivitis and asthma in the next months. In this review, new developments in the field of tablet-based SLIT for respiratory allergy are summarized, with special emphasis on HDM-induced allergic rhinitis and asthma. SLIT tablets are the best-documented immunotherapy products on the market and represent a more patient-friendly concept because they can be self-administrated at home.

Biomarkers for monitoring clinical efficacy of allergen immunotherapy for allergic rhinoconjunctivitis and allergic asthma: an EAACI Position Paper

BACKGROUND

Allergen immunotherapy (AIT) is an effective treatment for allergic rhinoconjunctivitis (AR) with or without asthma. It is important to note that due to the complex interaction between patient, allergy triggers, symptomatology and vaccines used for AIT, some patients do not respond optimally to the treatment. Furthermore, there are no validated or generally accepted candidate biomarkers that are predictive of the clinical response to AIT. Clinical management of patients receiving AIT and efficacy in randomised controlled trials for drug development could be enhanced by predictive biomarkers.

METHOD

The EAACI taskforce reviewed all candidate biomarkers used in clinical trials of AR patients with/without asthma in a literature review. Biomarkers were grouped into seven domains: (i) IgE (total IgE, specific IgE and sIgE/Total IgE ratio), (ii) IgG-subclasses (sIgG1, sIgG4 including SIgE/IgG4 ratio), (iii) Serum inhibitory activity for IgE (IgE-FAB and IgE-BF), (iv) Basophil activation, (v) Cytokines and Chemokines, (vi) Cellular markers (T regulatory cells, B regulatory cells and dendritic cells) and (vii) In vivo biomarkers (including provocation tests?).

RESULTS

All biomarkers were reviewed in the light of their potential advantages as well as their respective drawbacks. Unmet needs and specific recommendations on all seven domains were addressed.

CONCLUSIONS

It is recommended to explore the use of allergen-specific IgG4 as a biomarker for compliance. sIgE/tIgE and IgE-FAB are considered as potential surrogate candidate biomarkers. Cytokine/chemokines and cellular reponses provided insight into the mechanisms of AIT. More studies for confirmation and interpretation of the possible association with the clinical response to AIT are needed.

Novel approaches and perspectives in allergen immunotherapy

In this review, we report on relevant current topics in allergen immunotherapy (AIT) which were broadly discussed during the first Aarhus Immunotherapy Symposium (Aarhus, Denmark) in December 2015 by leading clinicians, scientists and industry representatives in the field. The aim of this symposium was to highlight AIT-related aspects of public health, clinical efficacy evaluation, mechanisms, development of new biomarkers and an overview of novel therapeutic approaches. Allergy is a public health issue of high socioeconomic relevance, and development of evidence-based action plans to address allergy as a public health issue ought to be on national and regional agendas. The underlying mechanisms are in the focus of current research that lays the ground for innovative therapies. Standardization and harmonization of clinical endpoints in AIT trials as well as current knowledge about potential biomarkers have substantiated proof of effectiveness of this disease-modifying therapeutic option. Novel treatments such as peptide immunotherapy, intralymphatic immunotherapy and use of recombinant allergens herald a new age in which AIT may address treatment of allergy as a public health issue by reaching a large fraction of patients.

Patient selection for subcutaneous versus sublingual immunotherapy

PURPOSE OF REVIEW

With the Food and Drug Administration's approval of sublingual allergen-specific immunotherapy (SL-AIT) tablets for grass and ragweed pollen, SL-AIT is progressively gathering importance not only in Europe, but also in the United States and other parts of the world. We reviewed issues related to the selection of patients for the sublingual or the subcutaneous route for allergic patients, based on what has been published since January 2014 on subcutaneous-versus-SL-AIT efficacy, safety and other issues. (Figure is included in full-text article.)

RECENT FINDINGS

As patient's adherence seems one of the major problems in real-life AIT, investigators have sought how to enhance AIT simplicity by changing the route to home-administrated SL-AIT, and by shortening the subcutaneous-allergen-specific immunotherapy (SC-AIT) build-up or maintenance phase. The latter was safe with several hypoallergenic extracts. As for SL-AIT, double blind placebo-controlled large trials in patients with allergic rhinitis and asthma have shown the efficacy and safety of ragweed pollen and house dust mite SLIT tablets and highly concentrated liquid formulations, primarily in adults. A large trial with SLIT in 3-year-old children was effective.

SUMMARY

With the improvement of SL-AIT efficacy, the selection of SC-versus-SL-AIT will probably increasingly be based not on efficacy, but on practical aspects, without losing sight of which SL-AIT products have proven efficacy.

Intralymphatic immunotherapy of pollen-induced rhinoconjunctivitis: a double-blind placebo-controlled trial

Background

Allergen-specific immunotherapy represents the only disease-modifying treatment for allergic diseases. We and others have previously demonstrated that intralymphatic immunotherapy (ILIT), a less time-consuming alternative to conventional subcutaneous immunotherapy (SCIT), is safe and effective. However, this has recently been disputed. The aim of this study was therefore to expand our previous trial, further assessing the safety and efficacy of ILIT.

Methods

Thirty-six patients with pollen-induced rhinoconjunctivitis were randomised to receive three intralymphatic inguinal injections of active allergen (1000 SQ-U birch- or grass-pollen) or placebo. Clinical effects, safety and circulating immunological markers were assessed before, 4 weeks after treatment and at the end of the consecutive pollen season.

Results

No moderate or severe reactions were recorded following ILIT. Patients receiving active ILIT experienced a significant improvement in self-recorded seasonal allergic symptoms, as compared to placebo (p = 0.05). In a subgroup of these patients (“improved”), a reduction in nasal symptoms following nasal allergen provocation was also demonstrated. No changes in total IgE or IgG₄ were found. However, the affinity of allergen specific IgG₄ following active treatment was significantly increased, as compared to non-improved patients (p = 0.04). This could be correlated with clinical improvement, on an individual level.

Conclusions

This double-blinded placebo-controlled study confirms that ILIT is a safe and effective treatment for pollen-induced rhinoconjunctivitis, markedly reducing seasonal allergic symptoms.

Trial registration

EudraCT: 2009-016815-39

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0324-9) contains supplementary material, which is available to authorized users.