Environmental exposure unit simulates natural seasonal birch pollen exposures while maximizing change in allergic symptoms

Full consideration of the pollen exposure effect in clinical trial design for pollen-induced allergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is global health concern with an increasing prevalence. Among them, pollen-induced AR (PIAR) exhibits more severe and intense symptoms, decreased quality of life, prominent local inflammation, and is thus more challenging to control. Due to the difficulties in disease control, in recent years, an increasing number of treatment methods, including pharmacotherapy, allergen-specific immunotherapy, and newly developed biologics, have focused on PIAR. It has been shown that the pollen exposure has a significant impact on the symptoms of PIAR and the efficacy of intervention. From this perspective, clinical trials for PIAR need to take full account of pollen exposure, especially when assessing efficacy.

AREAS COVERED

This review summarized the effect of pollen exposure on PIAR, including immune responses, symptoms and clinic visits. Current definitions for the pollen season (PS) and the peak pollen season (PPS) are discussed. Based on the previous PIAR-related clinical studies and the available recommendations for clinical trial design, a detailed account of trial protocols which fully considered pollen exposure is provided.

EXPERT OPINION

Pollen exposure has a significant impact on PIAR. With fully considering the pollen exposure in the clinical trial design for PIAR, future protocols for PIAR-related studies may be more objective and better harmonized and, therefore, comparable.

A Modern Approach to Clinical Outcome Assessment in Allergy Management: Advantages of Allergen Exposure Chambers

Allergic diseases triggered by airborne allergens such as allergic rhinitis and conjunctivitis are increasingly prevalent, posing significant challenges for both patients and healthcare systems. Assessing the efficacy of allergen immunotherapy and other anti-allergic treatments requires precise and reproducible methods. Allergen exposure chambers (AECs) have emerged as advanced tools for evaluating clinical outcomes, offering controlled conditions that address many limitations of traditional field-based studies. This review explores the advantages of AECs in allergy management, emphasizing their role in providing standardized allergen exposure for both clinical research and routine assessments. AECs deliver consistent and reproducible data comparable to the nasal allergen challenge and natural allergen exposure, making them a valuable addition to the diagnosis and treatment effectiveness of allergic diseases. Although they are well suited to early-stage clinical trials, further standardization and validation are needed to gain broader acceptance in pivotal phase III studies. Future research should focus on refining AEC protocols and integrating them into regulatory frameworks, ensuring their role in the advancement of therapeutic approaches for allergic diseases.

Alleviation of Allergic Rhinoconjunctivitis Symptoms in Participants Treated with a 0.005% Tacrolimus Eye-Drop Solution

Purpose

This randomized, placebo-controlled, crossover, double-blind trial aimed to evaluate the efficacy and safety of Tacrosolv, a novel 0.005% tacrolimus eye-drop solution, in adults with grass pollen-induced allergic conjunctivitis.

Methods

A total of 64 adult participants were randomized to receive 2.5 µg or 5 µg tacrolimus/eye/day or placebo treatment for 8 days, with grass pollen exposure on day 1 and day 8. After a 2-week washout period, placebo participants crossed over to Tacrosolv treatment and vice versa, with repeated treatment and exposure. During exposure, participants recorded ocular, nasal, and respiratory allergy symptoms every 15 minutes. The primary endpoint was the mean total ocular symptom score (TOSS) on day 8. Objective ocular safety parameters were assessed before, during, and after exposure. Adverse events were recorded throughout the study.

Results

On day 8, high-dose Tacrosolv reduced the TOSS compared to placebo towards the end of exposure (p<0.05 at time points 3 hours, 45 minutes and 4 hours). A 26% reduction in baseline adjusted TOSS from day 1 to day 8 was observed in participants treated with high-dose Tacrosolv, whereas placebo-treated participants showed no difference in TOSS between day 1 and day 8. Nasal symptoms were reduced on both day 1 and day 8 in participants treated with high-dose Tacrosolv (p<0.05). No safety concerns were raised. All adverse events were resolved within the study period.

Conclusion

High-dose Tacrosolv is safe and effective for alleviating symptoms of allergic rhinoconjunctivitis.

Trial Registration

NCT04532710; EudraCT No. 2019-002847-62.

Birch-induced allergic rhinitis: Results of exposure during nasal allergen challenge, environmental chamber, and pollen season

Background

Pollen variation can affect field study data quality. Nasal allergen challenge (NAC) is considered the gold standard for evaluating allergic rhinitis, while environmental exposure chambers (EECs) are mainly used in phase 2 drug development studies. We aimed to study birch-induced allergic rhinitis under 3 different conditions.

Methods

This study included 30 participants allergic to birch pollen, based on birch skin prick test, specific immunoglobulin E (IgE), and positive NAC. Participants were exposed to placebo twice, followed by 2 consecutive 4-h birch airborne exposures, repeated on 2 occasions to evaluate reproducibility and priming effect. Nasal response was defined as total corrected nasal symptom score (ΔTNSS) ≥ 5 during NAC and EEC. The primary end-point was to measure TNSS during the last 2 h of first allergen exposure. TNSS was also analyzed during natural exposure.

Results

The dose most commonly yielding positive TNSS during NAC was 175.2 ng/200 μL. Eighteen participants experienced ΔTNSS ≥5 during the last 2 h of the first exposure, whereas 21 had positive responses at all 4 exposures. Mean ΔTNSS was 1 with placebo versus 6 with birch. Exposures were reproducible, with no observed priming effect. Airborne Bet v 1 was 25 ng/m³, while the pollen measurement was 279/m³ during pollen season. TNSS reached 5 in 67.9% of participants during peak pollen season.

Conclusion

EEC outcomes were similar to those obtained with NAC and natural exposure, suggesting the usefulness of EEC in allergic rhinitis studies. The primary end-point was reached, as 60% of participants experienced nasal responses.

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.

REGN1908/1909 prevented cat allergen-induced early asthmatic responses in an environmental exposure unit

BACKGROUND

The dominant allergen in cat dander, Felis domesticus allergen 1 (Fel d 1), is a persistent trigger for allergic rhinitis and asthma symptoms.

OBJECTIVE

We evaluated the efficacy of Fel d 1 monoclonal antibodies (REGN1908/1909) in preventing cat allergen-induced early asthmatic responses (EARs) in cat-allergic patients with mild asthma.

METHODS

Patients were randomized to single-dose REGN1908/1909 600 mg (n = 29) or placebo (n = 27). The FEV₁ was measured for up to 4 hours in a cat allergen environmental exposure unit up to 85 days after dosing. Assessments included between-group differences in change from baseline in FEV₁ area under the curve (AUC; 0-2 hours) and incidence of EAR (FEV₁ reduction ≥20%).

TRIAL REGISTRATION

NCT03838731.

RESULTS

Single-dose REGN1908/1909 significantly prevented reductions in FEV₁ on days 8, 29, 57, and 85. Most REGN1908/1909 patients did not have an EAR by 4 hours (the last time point tested). In contrast, placebo-treated patients experienced a ≥20% mean FEV₁ reduction on days 8, 29, 57, and 85 after dosing, with most experiencing an EAR within 1 hour. REGN1908/1909-treated patients tolerated 3-fold higher allergen quantities (P < .05 at all time points) versus placebo. REGN1908/1909 substantially reduced skin test reactivity to cat allergen versus placebo at all time points tested (nominal P < .001). REGN1908/1909 was generally well tolerated; no serious adverse events or deaths were reported.

CONCLUSION

Single-dose REGN1908/1909 significantly prevented reductions in FEV₁ in cat-allergic patients with mild asthma on cat allergen environmental exposure unit exposure at 8 days and up to 85 days after dose.