The role of allergen challenge chambers in the evaluation of anti-allergic medication: an international consensus paper

Efficacy of N-acetyl aspartyl glutamic acid versus fluorometholone for treating allergic conjunctivitis in an environmental exposure chamber

Background

Topical mast cell stabilizers were previously shown to treat the signs and symptoms of seasonal and perennial allergic conjunctivitis safely and effectively in active and placebo‐controlled trials. However, mast cell stabilizers have not been compared to topical corticosteroids for efficacy. We tested the non‐inferiority of a topical mast cell stabilizer, N‐acetyl aspartyl glutamic acid (4.9%, NAAGA), compared to fluorometholone (0.1%, FM) during controlled exposures to the airborne birch pollen allergen, Bet v 1, in an environmental exposure chamber (EEC).

Methods

This randomized, cross‐over, investigator‐blinded study included 24 patients with a history of birch pollen allergic conjunctivitis. Patients were randomized to 5 days of treatment with NAAGA, then FM (n = 12) or FM, then NAAGA (n = 12). After each treatment, patients were exposed to a fixed airborne concentration of Bet v 1 in ALYATEC EEC. The primary endpoint was the amount of allergen required to trigger a conjunctival response (Abelson score ≥5). Groups were compared with a linear model for cross‐over studies. Non‐inferiority was assumed, when the lower bound of the risk ratio confidence interval (CI) was >0.5.

Results

At screening, the mean time‐to‐conjunctival response was 72.5 ± 35.9 min. NAAGA and FM extended the response time to 114.8 ± 55.0 and 116.6 ± 51.5 min respectively. The mean amounts of allergen required to trigger a conjunctival response were 1.165 ng after NAAGA and 1.193 ng after FM treatment. The risk ratio for the conjunctival response was 0.977 (95% CI: 0.812; 1.174), which indicated non‐inferiority. Adverse events occurred less frequently with NAAGA (29.2%) than with FM (58.3%).

Conclusion

In patients with allergic conjunctivitis to birch pollen, NAAGA was non‐inferior to FM in exposures to airborne Bet v 1. The EEC was a good model for simulating real‐life airborne allergen exposure and for demonstrating the efficacy and safety of eye drops for treating allergic conjunctivitis.

Trial registration

Not registered.

Technical standards in allergen exposure chambers worldwide - an EAACI Task Force Report

Allergen exposure chambers (AECs) can be used for controlled exposure to allergenic and non-allergenic airborne particles in an enclosed environment, in order to (i) characterize the pathological features of respiratory diseases and (ii) contribute to and accelerate the clinical development of pharmacological treatments and allergen immunotherapy for allergic disease of the respiratory tract (such as allergic rhinitis, allergic rhinoconjunctivitis, and allergic asthma). In the guidelines of the European Medicines Agency for the clinical development of products for allergen immunotherapy (AIT), the role of AECs in determining primary endpoints in dose-finding Phase II trials is emphasized. Although methodologically insulated from the variability of natural pollen exposure, chamber models remain confined to supporting secondary, rather than primary, endpoints in Phase III registration trials. The need for further validation in comparison with field exposure is clearly mandated. On this basis, the European Academy of Allergy and Clinical Immunology (EAACI) initiated a Task Force in 2015 charged to gain a better understanding of how AECs can generate knowledge about respiratory allergies and can contribute to the clinical development of treatments. Researchers working with AECs worldwide were asked to provide technical information in eight sections: (i) dimensions and structure of the AEC, (ii) AEC staff, (iii) airflow, air processing, and operating conditions, (iv) particle dispersal, (v) pollen/particle counting, (vi) safety and non-contamination measures, (vii) procedures for symptom assessments, (viii) tested allergens/substances and validation procedures. On this basis, a minimal set of technical requirements for AECs applied to the field of allergology is proposed.

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.

Utility of Environmental Exposure Unit Challenge Protocols for the Study of Allergic Rhinitis Therapies

PURPOSE OF REVIEW

This paper explores how the Environmental Exposure Unit (EEU) experimental model can be used to further our understanding of pharmacotherapies and immunotherapies for the treatment of allergic rhinitis (AR).

RECENT FINDINGS

EEUs are used increasingly for the study of combination therapies, immunotherapies, and novel AR treatments. A combined antihistamine/corticosteroid nasal spray formulation was seen to have a faster onset of action relative to the therapies individually in the Environmental Exposure Chamber. House dust mite sublingual immunotherapy tablets are both safe and efficacious as evaluated by the Vienna Challenge Chamber. The Kingston EEU found that a novel peptide-based immunotherapy approach to be effective in reducing grass pollen-induced AR. Lastly, nasal filters were determined to reduce seasonal AR symptoms, given out-of-season in the Denmark Environmental Exposure Unit. EEUs are controlled, replicable models that provide valuable insight into the efficacy, onset and duration of action, and dose-related impacts of AR therapeutics, with direct clinical relevance.

Validation of Strasbourg environmental exposure chamber (EEC) ALYATEC® in mite allergic subjects with asthma

Objective: Environmental Exposure Chamber (EEC) should have standardized and controlled allergenic and non-allergenic exposures to perform reproducible clinical studies. The aim was to demonstrate that mite exposure in the Alyatec^® EEC could induce early (EAR) and/or late asthmatic reactions (LAR) in at least 60% of subjects allergic to mite.Methods: The EEC has a volume of 147-m³ with 20 seats. The nebulized particle number, airborne Der p1, endotoxins, and volatile organic compound (VOC) concentrations were measured. Twenty-four asthmatics allergic to mite were randomly exposed to 15, 25, and 46 ng/m³ Der p1. Specificity was assessed in not mite-sensitized asthmatics.Results: No significant endotoxin or VOC contamination was measured. The mean inter-assay CVs were 12.5% for the airborne particle number and 28.7% for airborne Der p1 concentrations. For the three Der p1 concentrations, at least 88% of the subjects developed EAR and/or LAR, and at least 46% developed a dual response. No reaction occurred with placebo or in the control group. No severe bronchial reaction occurred.Conclusions: The Alyatec^® EEC demonstrated a tight control of allergenic and non-allergenic exposures. The EEC was clinically validated, with airborne Der p1 levels close to levels found in natural settings.

Clinical standardization of two controlled allergen challenge facilities: The Environmental Exposure Unit and the Biogenics Research Chamber

BACKGROUND

Controlled allergen challenge facilities (CACF), in disparate geographic regions with dissimilar engineering and base populations, have historically functioned as single, independent sites in clinical allergy trials. We aimed to demonstrate "between-unit reproducibility" to allow controlled challenge trials of participants using 2 CACFs.

OBJECTIVE

To compare and standardize 2 CACFs located in Kingston, Ontario, Canada, and San Antonio, Texas, by examining participant-reported symptom severity during qualifying and treatment visits and evaluating response to treatment, while using the same allergen.

METHODS

At 2 different CACFs, participants were enrolled in a double-blind, placebo-controlled, crossover intervention trial with cetirizine 10 mg. Different distribution devices delivered common short ragweed pollen via laminar air flow and maintained an airborne concentration of 3500 ± 700 grains/m³ in both facilities. A 1-hour "sham" run with no pollen release preceded a priming exposure of 3 hours and was followed 3 days later by a qualifying/treatment 5-hour exposure. At least 14 days later, another priming exposure was followed by the crossover exposure and treatment.

RESULTS

Forty-eight and 43 subjects completed the study at Kingston and San Antonio, respectively. Demographics were similar. Fewer than 10% exhibited symptoms with sham exposure. No significant differences were found between the 2 facilities in maximal total rhinoconjunctivitis symptom score, total nasal symptom score, and total ocular symptom score, nor in areas under the curve. In both facilities, no significant effects of cetirizine 10 mg over placebo were detected.

CONCLUSION

The results were equivalent, demonstrating that the 2 CACFs can be used together in dual-center clinical trials and show the possibility of multicenter trials involving multiple CACFs.

[Environmental exposure chambers (EEC): A novel tool for pathophysiological and pharmaceutical research]

Airborne allergic diseases (allergic asthma, rhinitis and conjunctivitis) have reached epidemic proportions and are a great burden for both society and individuals. Therefore we need to better understand the physiopathological mechanisms and to increase clinical research in these diseases. However, traditional outpatient studies are difficult and have number of limitations, in particular the variability of allergen exposure. Yet allergen provocation tests, especially bronchial challenges in asthma, are excellent tools to measure the efficiency of anti-allergic therapies. Environmental exposure chambers (EEC) allow the performance of controlled allergen provocation tests on a large scale with remarkable sensitivity, specificity and reproducibility. Moreover, they allow a precise collection of allergic symptoms, making them interesting tools for patho-physiological and clinical studies. During the last thirty years, they have assisted the study of anti-allergic therapies and provided data on their pharmacodynamic characteristics, particularly in allergic rhinitis. However, there are still no EEC tests centered on asthma. The EEC of Strasbourg (ALYATEC^®) was developed to fulfill two objectives: to allow standardized allergenic and non-allergenic exposures with better control of the parameters than in other EEC and to offer a place to study asthma and anti-asthmatic therapies safely.

Peak nasal inspiratory flow as outcome for provocation studies in allergen exposure chambers: a GA2LEN study

Background

The GA²LEN chamber has been developed as a novel mobile allergen exposure chamber (AEC) allowing standardized multicenter trials in allergy. Hitherto, subjective nasal symptom scores have been the most often used outcome parameter, but in standardized modern trials objective parameters are preferred. Despite its practicability, the objective parameter peak nasal inspiratory flow (PNIF) has been rarely used for allergy trials in the setting of allergen exposure chambers. This study aims to evaluate PNIF as an outcome parameter for provocation studies in AECs.

Methods

In a randomized controlled blinded setting subjects suffering from allergic rhinitis were exposed to grass pollen, birch pollen, house dust mite and/or placebo in the GA²LEN chamber. Different allergen concentrations were used to evaluate symptom severities. Patients had to perform PNIF before and every 30 min during a challenge using a portable PNIF meter.

Results

86 subjects participated in 203 challenges, altogether. House dust mite provocations caused the greatest reduction in PNIF values, followed by grass pollen and birch pollen. Provocations with every allergen or pollen concentration led to a significant decrease (p < 0.05) in PNIF compared to baseline. Furthermore, positive correlations were obtained between PNIF and peak expiratory flow, height and weight, and inverse correlations between PNIF and total nasal symptom score, nasal congestion score and visual analog scale of overall subjective symptoms.

Conclusion

PNIF is a helpful and feasible tool for conducting provocation trials with allergens, especially grass pollen and house dust mite, in an AEC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-017-0169-4) contains supplementary material, which is available to authorized users.

Allergen exposure chambers: harmonizing current concepts and projecting the needs for the future - an EAACI Position Paper

BACKGROUND

Allergen exposure chambers (AECs) are clinical facilities allowing for controlled exposure of subjects to allergens in an enclosed environment. AECs have contributed towards characterizing the pathophysiology of respiratory allergic diseases and the pharmacological properties of new therapies. In addition, they are complementary to and offer some advantages over traditional multicentre field trials for evaluation of novel therapeutics. To date, AEC studies conducted have been monocentric and have followed protocols unique to each centre. Because there are technical differences among AECs, it may be necessary to define parameters to standardize the AECs so that studies may be extrapolated for driving basic immunological research and for marketing authorization purposes by regulatory authorities.

METHODS

For this task force initiative of the European Academy of Allergy and Clinical Immunology (EAACI), experts from academia and regulatory agencies met with chamber operators to list technical, clinical and regulatory unmet needs as well as the prerequisites for clinical validation.

RESULTS

The latter covered the validation process, standardization of challenges and outcomes, intra- and interchamber variability and reproducibility, in addition to comparability with field trials and specifics of paediatric trials and regulatory issues.

CONCLUSION

This EAACI Position Paper aims to harmonize current concepts in AECs and to project unmet needs with the intent to enhance progress towards use of these facilities in determining safety and efficacy of new therapeutics in the future.

Therapeutic effect of bilastine in Japanese cedar pollinosis using an artificial exposure chamber (OHIO Chamber)

BACKGROUND

Environmental exposure chambers have been used to expose subjects to aeroallergens to investigate the efficacy of prophylactic treatment with symptomatic agents in Japan. We first examined the therapeutic effect of bilastine (BIL), a novel non-sedative second-generation H₁-antihistamine, in subjects with Japanese cedar pollinosis using an artificial exposure chamber (OHIO Chamber).

METHODS

This was a randomized, double-blind, four-way crossover, placebo- and active-controlled phase II study (trial registration number JapicCTI-132213). Subjects were exposed to cedar pollen (8000 grains/m³) for 2 h on Day -1 and 4 h each on Day 1 and 2. BIL 10 or 20 mg, placebo, or fexofenadine hydrochloride (FEX) 60 mg was administered orally 1 h after the start of pollen exposure on Day 1. Placebo or FEX was administered 12 h after the first dosing. The primary efficacy endpoint was the sum of total nasal symptom score (TNSS) from 0 to 3 h after the Day 1 dosing.

RESULTS

We enrolled 136 subjects and the sum of TNSS on Day 1 of the three active treatments was significantly lower than that of placebo and was maintained up to 26 h after the first dosing (Day 2). The sum of TNSS or sneezing score on Day 1 after BIL 20 mg was more significantly decreased than after FEX. Moreover, BIL showed a faster onset of action than FEX.

CONCLUSIONS

We demonstrated the efficacy, rapid onset, and long duration of action of BIL in subjects with Japanese cedar pollinosis exposed to cedar pollen using the OHIO Chamber.

Conjunctival allergen provocation test : guidelines for daily practice

Conjunctival allergen provocation test (CAPT) reproduces the events occurring by instilling an allergen on the ocular surface. This paper is the compilation of a task force focussed on practical aspects of this technique based on the analysis of 131 papers. Main mechanisms involved are reviewed. Indications are diagnosing the allergen(s)-triggering symptoms in IgE-mediated ocular allergy in seasonal, acute or perennial forms of allergic conjunctivitis, especially when the relevance of the allergen is not obvious or in polysensitized patients. Contraindications are limited to ongoing systemic severe pathology, asthma and eye diseases. CAPT should be delayed if receiving systemic steroids or antihistamines. Local treatment should be interrupted according to the half-life of each drug. Prerequisites are as follows: obtaining informed consent; evidencing of an allergen by skin prick tests and/or serum-specific IgE dosages; being able to deal with an unlikely event such as acute asthma exacerbation, urticaria or anaphylaxis, or an exacerbation of allergic conjunctivitis. Allergen extracts should be diluted locally prior to administration. Positive criteria are based on itching or quoted according to a composite score. An alternative scoring is based on itching. CAPT remains underused in daily practice, although it is a safe and simple procedure which can provide valuable clinical information.

Validation of the Global Allergy and Asthma European Network (GA2LEN) chamber for trials in allergy: Innovation of a mobile allergen exposure chamber

BACKGROUND

Field clinical trials of pollen allergy are affected by the impossibility of predicting and determining individual allergen exposure because of many factors (eg, pollen season, atmospheric variations, pollutants, and lifestyles). Environmental exposure chambers, delivering a fixed amount of allergen in a controlled environmental setting, can overcome these limitations. Environmental exposure chambers are currently already used in phase 2, 3, and even 4 trials. Unfortunately, few chambers exist in the world, and this makes it difficult to perform large, multicenter clinical trials. The new Global Allergy and Asthma European Network (GA²LEN) mobile exposure chamber is a step forward because the mobility of the chamber makes it convenient for patients to participate in clinical testing.

OBJECTIVE

This study was made to validate the reproducibility, sensitivity, and specificity of the results obtained in the new GA²LEN chamber.

METHODS

Seventy-two adult patients (19-61 years old) with allergic rhinitis with or without asthma caused by grass pollen were included in different clinical validation tests. Total symptom scores and total nasal symptom scores were recorded at time zero (0) and every 10 minutes during exposures, along with nasal and respiratory parameters.

RESULTS

Exposure tests confirmed the reproducibility between subsequent runs and the sensitivity (P < .00001 vs patients exposed to placebo) and specificity (very low score in nonallergic subjects) in the GA²LEN chamber. No adverse reactions were recorded during the tests.

CONCLUSIONS

The mobility of the GA²LEN chamber provides a new, potentially effective, and safe way of generating reliable data in allergy multicenter clinical trials.

New opportunities for allergen immunotherapy using synthetic peptide immuno-regulatory epitopes (SPIREs)

INTRODUCTION

Allergen immunotherapy (AIT) reduces allergic rhinoconjunctivitis (ARC) symptoms, but long-term efficacy requires treatment for 3-5 years. Synthetic peptide immuno-regulatory epitopes, a new class of AIT, are allergen peptides with a shorter, more convenient treatment regimen that could potentially have benefits on adherence and outcomes.

AREAS COVERED

Phase 2 trials of therapies derived from cat, house dust mite, grass, and ragweed allergen peptides demonstrated significant reduction in ARC symptoms after short-course treatment; improvement was sustained for 18-24 months posttreatment. We conducted a PubMed literature search for clinical publications using the search terms AIT; allergen peptides; ARC; cat, grass, house dust mite, and ragweed allergy; SCIT; SLIT; and synthetic peptides. Expert commentary: Long-term disease modification is a realistic goal of AIT. The inconvenience of conventional AIT regimens negatively impacts long-term persistence and, thus, efficacy. In comparison, SPIREs have a more convenient treatment regimen that could potentially have benefits on adherence and outcomes.

Method for a homogeneous distribution of pollens in an environmental exposure chamber

BACKGROUND

A variety of different environmental exposure chambers (EECs) have been used to evaluate treatments for allergic rhinitis.

OBJECTIVE

To describe and test a system for a homogenous distribution of grass pollen, Phleum Pratense, in an EEC to be used for controlled pollen exposure studies in allergic participants.

METHODS

A chamber made of stainless steel with completely rounded corners, seating four individuals at a time, was used. Room pressure, temperature, humidity and the air change rate were kept constant throughout the study period. A rotating pipette dispensed a uniform supply of pollen into a turntable's v-shaped grooves. A stainless steel capillary tube sucked the pollens into a venturi throat at which time the pollens were mixed with a high-pressure airstream of compressed high-efficiency particulate arrestance filtered air and then transported to a spreading plate inside the EEC. To achieve uniform concentrations in the EEC, the turntable's rotating speed was continuously adjusted using information from video-coupled feedback and feed forward mechanisms. Pollen levels were detected using standard volumetric air samplers and laser particle counters. The target pollen exposure level was 1000 pollens/m(3) . Twenty-one participants were exposed to pollens in the EEC twice for 210 min. Participants evaluated their symptoms every 30 min using a total nasal symptom score (TNSS) consisting of blocked nose, runny nose, nasal itching and sneezing.

RESULTS

Across fifteen study days, the average pollen level was 982 pollens/m(3) (SD, 102 pollens/m(3) ). On average, participants experienced a 10% difference in overall pollen levels between their two visits to the EEC. The mean TNSSs rose throughout the exposure period, with a low at baseline of 0.43 (SD, 0.68) to a high of 4.71 (SD, 2.43) just before exiting the EEC.

CONCLUSION AND CLINICAL RELEVANCE

This EEC provides a reproducible, precise and homogenous distribution of pollens making it suitable for single-centre allergy clinical trials.

The improved efficacy of a fixed-dose combination of fluticasone furoate and levocabastine relative to the individual components in the treatment of allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is a common chronic disease, which has significant detrimental effect on well-being and quality of life as well as substantial socio-economic impact. Combination pharmacotherapy is utilized by 40-50% of patients to treat their symptoms.

OBJECTIVE

To compare the effects of intranasal fluticasone furoate (FF)/levocabastine (LEVO) fixed-dose combination (FDC) with each component alone on allergen-induced nasal and ocular symptoms.

METHODS

A randomized, double-blind, placebo-controlled, three-way, incomplete block, cross-over, proof-of-concept study in 71 patients with AR, evaluated FF 100 μg, LEVO 200 μg and FDC (FF 100/LEVO 200 μg), once daily via intranasal spray for 8 days. On days 1 and 8, total nasal symptom score (TNSS) and total ocular symptom score (TOSS) were assessed every 15 min during a 4-h allergen exposure in the Vienna Challenge Chamber. The primary endpoint was Day 8 weighted mean TNSS.

RESULTS

After 8 days, FDC resulted in both statistically and clinically significant reductions in mean TNSS compared with FF and LEVO alone [adjusted mean differences (95% CI): FDC vs. FF: -2.26 (-2.90, -1.62); FDC vs. LEVO: -2.57 (-3.21, -1.93)]. All active treatments were significantly superior to placebo [adjusted mean difference (95% CI) from placebo: FDC: -4.1 (-4.86, -3.34); FF: -1.84 (-2.66, -1.03); LEVO: -1.53 (-2.34, -0.72)]. Onset of action was rapid following FDC and LEVO treatment with an approximate two unit reduction in mean TNSS from pre-dose levels by 30 min and 1 h. Mean TOSS was also reduced following all active treatments relative to placebo (range 0.6-0.8 unit reduction). All treatments were equally well tolerated.

CONCLUSIONS AND CLINICAL RELEVANCE

These results suggest that once daily FF/LEVO FDC could provide a clinical therapeutic advantage to existing standard monotherapies in the treatment of moderate-to-severe AR, and support progression to evaluation in larger phase III clinical studies.

Controlled Allergen Challenge Facilities and Their Unique Contributions to Allergic Rhinitis Research

The aim of this study is to review advances in basic and clinical allergic rhinitis (AR) research over the past decade that have been conducted using controlled allergen challenge facility (CACF) models of allergen challenge. Databases, including PubMed, Medline, and Web of Science were searched for articles employing an ambient pollen exposure in a controlled facility to study AR, published between 2004 and the present date, using the terms as follows: CACF, Environmental Exposure Unit (EEU), Vienna Challenge Chamber (VCC), Fraunhofer Institute Environmental Challenge Chamber, Atlanta Allergen Exposure Unit, Biogenics Research Chamber, Allergen BioCube, Chiba and Osaka Environmental Challenge Chamber, exposure unit, challenge chamber, or environmental exposure chamber. Articles were then selected for relevance to the goals of the present review, including important contributions toward clinical and/or basic science allergy research. CACFs offer sensitive, specific, and reproducible methodology for allergen challenge. They have been employed since the 1980s and offer distinct advantages over traditional in-season multicentre trials when evaluating new treatments for AR. They have provided clinically applicable efficacy and pharmacologic information about important allergy medications, including antihistamines, decongestants, antileukotrienes, immunotherapies, and nasal steroids. CACF models have also contributed to basic science and novel/experimental therapy research. To date, no direct studies have been conducted comparing outcomes from one CACF to another. Over the past decade, CACF models have played an essential role in investigating the pathophysiology of AR and evaluating new therapies. The future opportunities for this model continue to expand.

Preventive effect of nasal filters on allergic rhinitis: A randomized, double-blind, placebo-controlled crossover park study

BACKGROUND

A recently reported small, out-of-season environmental exposure unit study found nasal filters to be efficacious in preventing seasonal allergic rhinitis (AR). However, nasal filters still need to show efficacy in a natural setting in a regular pollen season.

OBJECTIVE

We sought to evaluate the efficacy of nasal filters (Rhinix; Rhinix ApS, Aarhus, Denmark) for the prevention of symptoms related to seasonal AR.

METHODS

The trial was a single-center, randomized (1:1), double-blind, placebo-controlled crossover clinical trial (NCT02108574) conducted over 2 days in the main grass pollen season in June 2014 in Aarhus, Denmark, on 65 adults with proven grass allergy. A total nasal symptom score (TNSS) consisting of blocked nose, runny nose, nasal itching, and sneezing was used to evaluate symptoms. The difference in daily∑ TNSS (the sum of 13 ratings) was the primary outcome measure. The difference in maximum TNSS (highest score, 13 ratings) was also evaluated.

RESULTS

The nasal filters significantly reduced daily∑ TNSSs (P = .03) and maximum TNSSs (P = .03) compared with placebo. Median relative reductions were 40% for daily∑ TNSSs (P = .02), 43% for maximum TNSSs (P = .004), 83% for daily∑ sneezing (P = .001), 75% for daily∑ watery eyes (P = .02), and 53% for daily∑ runny nose (P = .005) when compared with placebo. The nasal filters were well tolerated, and no serious adverse events were recorded.

CONCLUSION

Statistically significant and clinically relevant reductions were achieved for the primary outcome measure of daily∑ TNSS, for maximum TNSS and for a subset of individual symptoms. The results support the preventive role of nasal filters for managing seasonal AR.

In vivo diagnosis of allergic diseases--allergen provocation tests

The allergen challenge test has been the mainstay of diagnosis of allergic diseases for a long time since it offers a direct proof of the clinical relevance of a particular allergen for the allergic disease symptoms and severity. Standardisation and availability for daily practice (including safety issues) are still to be refined but most of the challenge tests have safely crossed the border from research tools to diagnostic tests available for daily practice for a well trained clinical staff.

Negative clinical results from a randomised, double-blind, placebo-controlled trial evaluating the efficacy of two doses of immunologically enhanced, grass subcutaneous immunotherapy despite dose-dependent immunological response

OBJECTIVE

Specific immunotherapy is the only treatment for the underlying allergic disease in patients with respiratory allergies. The primary objective of this trial was to evaluate the efficacy and safety of two maintenance doses of immunologically enhanced, standardised quality (SQ+) grass subcutaneous immunotherapy (SCIT) [4,000 SQ+ and 15,000 SQ+; AVANZ(®) Phleum pratense (ALK)] compared with placebo.

METHODS

This was a randomised, double-blind, placebo-controlled, phase II/III trial. The primary evaluation was based on the combined rhinoconjunctivitis score during the entire grass pollen season. Adult subjects with grass pollen-induced allergic rhinoconjunctivitis interfering with usual activities or sleep despite symptomatic medication use, were enrolled.

RESULTS

Four hundred and fifty subjects were randomised to receive either 4,000 SQ+ (n = 150), 15,000 SQ+ (n = 152) or placebo (n = 148). The average grass pollen exposure was 27 grains/m(3)/day. No statistically significant differences between the active groups and the placebo group were found for clinical endpoints (p > 0.05). Highly statistically significant (p < 0.001) increases in IgG4 and IgE-blocking factor were found for both active groups versus placebo. The most frequently reported adverse events were mild-to-moderate local injection-site reactions; events were generally more frequent with 15,000 SQ+ than with 4,000 SQ+ and placebo. The most common adverse events leading to premature discontinuation from the trial were anaphylactic reactions (one subject from the placebo group and five subjects from the 15,000 SQ+ group).

CONCLUSIONS

The inconclusive results were most probably influenced by a very low grass pollen season. Other factors such as the extent of the pre-seasonal treatment could potentially have contributed. The tolerability profile was acceptable for further development.

Environmental exposure chambers in allergen immunotherapy trials: Current status and clinical validation needs

As required by the European Medicines Agency and the US Food and Drug Administration for pivotal trials involving allergen immunotherapy (AIT) products, clinical efficacy assessment is currently based on double-blind, placebo-controlled field studies with natural allergen exposure during the allergen season. However, this study design is associated with several drawbacks, such as the high variability of allergen exposure in different trial sites or seasons and the presence of confounding environmental factors. On the contrary, environmental exposure chambers (EECs) aim to operate with a stable and reproducible allergen exposure under highly standardized environmental conditions. Technical validation parameters for different EECs worldwide have been published by several groups. However, full clinical validation of EEC study outcomes is required for their classification as an appropriate alternative to natural allergen exposure for AIT product efficacy assessment. Some clinical validation parameters have already been addressed for EEC units. The reliability of provoked symptoms in repeated EEC sessions is high, but the predictive power of EEC settings for the clinical response on natural exposure and the impact of seasonal priming on test results still have to be validated systematically, as does the inter-EEC variability. Thus the authors recommend a continued in-depth validation of EECs to exploit the potential of this technology for future AIT product development.

Characteristics of the Chiba environmental challenge chamber

BACKGROUND

An environmental challenge chamber (ECC), which we refer to as the α-chamber, was built at Chiba University in 2008. The aim of this study was to validate the functionality of the ECC.

METHODS

The stability of the pollen distribution and concentration in the ECC and symptoms of patients with Japanese cedar pollinosis induced by cedar pollen exposure were examined. Carryover effects of symptoms induced by different exposure protocols and correlations between symptoms induced in the ECC and those in the natural cedar pollen season were also determined. All the studies using the α-chamber were conducted out of the cedar pollen season.

RESULTS

The severity of symptoms in the chamber reached a peak about 2 hours after the start of pollen exposure and plateaued thereafter. After subjects left the chamber, the symptoms persisted for several days. There was no significant difference between the severity of symptoms at exposure levels of 8000 and 12000 grains/m3. The symptoms were significantly increased by exposure for 3 consecutive days; however, there were no carryover effects in a study performed with a two-week interval. The total nasal symptom score (TNSS) in the natural pollen season showed a weak correlation with the mean TNSS on the day of exposure and the following 3 days. Symptoms in the ECC also had weak correlations with those in the early natural pollen season.

CONCLUSIONS

The ECC under well-controlled conditions is suitable for clinical studies and might accelerate development of treatment for seasonal allergic rhinitis. A complete evaluation requires inclusion of the persistent reaction after subjects leave the ECC.

An evidence-based analysis of house dust mite allergen immunotherapy: a call for more rigorous clinical studies

BACKGROUND

According to meta-analyses and reviews, subcutaneous allergen immunotherapy (SCIT) and sublingual allergen immunotherapy (SLIT) are beneficial in patients with allergic rhinitis (AR) and allergic asthma (AA) induced by house dust mites (HDMs). However, the reported effect sizes have varied greatly from one study to another.

OBJECTIVE

We sought to perform an evidence-based medicine assessment of commercially available SCIT and SLIT formulations in patients with HDM-induced AA and HDM-induced AR.

METHODS

We searched for double-blind, placebo-controlled randomized clinical trials and analyzed study designs, doses, regimens, patient-reported outcomes, safety reporting, and compliance.

RESULTS

Forty-four studies met our inclusion criteria. Some studies tested both SLIT and SCIT or scored both AA and AR outcomes; therefore we reviewed 35 treatment arms in patients with AA (20 for SCIT and 15 for SLIT) and 23 treatment arms in patients with AR (7 for SCIT and 16 for SLIT). The treatment duration ranged from 6 weeks to 3 years. For SCIT, the dose of Der p 1 major allergen (when reported) ranged from 7 to 30 μg for maintenance doses and 60 to 420 μg for cumulative doses. For SLIT, the doses of Der p 1 (when reported) were 0.8 to 70 μg for maintenance doses and 60 to 23,695 μg for cumulative doses. Safety data were often absent or poorly reported. A statistically significant active versus placebo symptom score was observed more frequently for SCIT than for SLIT.

CONCLUSION

There is no consensus on basic treatment parameters (eg, dose and duration) in HDM SCIT and SLIT. There is an urgent need for rigorous, long-term, double-blind, placebo-controlled randomized clinical trials with an efficacy criterion that reflects the particular features of HDM-induced allergic disease.

Cat peptide antigen desensitisation for treating cat allergic rhinoconjunctivitis

INTRODUCTION

Allergic rhinoconjunctivitis is an increasingly common source of morbidity with sensitivity to cats accounting for 10-15% of the disease burden. Allergy to cats is a major risk factor for the development of asthma.

AREAS COVERED

Within the present manuscript, the current data on a novel therapeutic approach to treat cat allergy is reviewed. Cat Peptide Antigen Desensitisation (Cat-PAD) is a mixture of seven small peptides developed for the treatment of cat allergy. It is designed to induce immunological tolerance via binding to MHC class II on antigen presenting cells and interacting with regulatory T cells without triggering the cross-linking of IgE on mast cells and basophils. The peptide sequences are derived from the major cat allergen Fel d 1. The peptides have been selected to ensure a similar T cell response to that generated to whole cat dander in ex-vivo PBMC derived from cat allergic individuals. The size of the peptides is insufficient to induce cross-linking of IgE. Clinical data from a series of studies shows that Cat-PAD is able to significantly reduce allergic rhinoconjunctivitis symptoms after a short course of four injections over 12 weeks, and that the treatment effect is persistent lasting 2 years after the start of treatment.

EXPERT OPINION

Taken together Cat-PAD is a novel, well tolerated and promising therapeutic approach to treat cat allergic patients. Data from the current international Phase III study will unravel whether the concept is also efficient and tolerable under daily life circumstances.

Fel d 1-derived peptide antigen desensitization shows a persistent treatment effect 1 year after the start of dosing: a randomized, placebo-controlled study

BACKGROUND

Allergic rhinoconjunctivitis is an increasingly common source of morbidity, with sensitivity to cats accounting for 10% to 15% of disease burden. Allergy to cats is also a major risk factor for the development of asthma.

OBJECTIVES

We sought to probe the persistence of the treatment effect of a novel F el d 1-derived peptide antigen desensitization (Cat-PAD) 1 year after the start of treatment in subjects with cat allergy-induced rhinoconjunctivitis after standardized allergen challenge.

METHODS

In a randomized, double-blind, placebo-controlled, parallel-group clinical trial, subjects attended an environmental exposure chamber in which they were exposed to cat allergen before and after treatment with 2 different regimens of Cat-PAD over a 3-month period. Clinical efficacy was assessed as a change in total rhinoconjunctivitis symptom scores 18 to 22 weeks and 50 to 54 weeks after the start of treatment.

RESULTS

Treatment with Cat-PAD showed greater efficacy with 4 administrations of a 6-nmol dose 4 weeks apart than with 8 administrations of a 3-nmol dose 2 weeks apart. The treatment effect of 6 nmol persisted 1 year after the start of treatment and was significantly different from that of 3 nmol (P = .0342) and placebo (P = .0104). The treatment effect was apparent on both nasal and ocular symptoms at 1 year.

CONCLUSIONS

A short course of Cat-PAD improves the ocular and nasal components of rhinoconjunctivitis symptoms in subjects with cat allergy, with the treatment effect persisting 1 year after the start of treatment.

Evaluating the effects of testing period on pollinosis symptoms using an allergen challenge chamber

BACKGROUND

We previously built a pollen challenge test unit (allergen challenge chamber: ACC) to collect objective data about Japanese cedar pollinosis. In this study, we investigated adequate conditions for pollen challenge using the ACC.

METHODS

The study consisted of two parts. The first part was conducted in November, which is not in pollen season. Subjects were exposed to Japanese cedar pollen at a concentration of 50,000 grains/m3 in the chamber for 120 min each day over the course of three consecutive days. The second part was conducted in April, which is just after pollen season. Subjects were exposed to Japanese cedar pollen at the same concentration (50,000 grains/m3) in the chamber for 90 min on a single day. Subjects recorded nasal and ocular symptoms before challenge and every 15 min after challenge initiation. The minimum cross-sectional area in the nasal cavity was measured using acoustic rhinometry before and after challenge as an indicator of nasal obstruction. Inflammatory markers in nasal lavage fluid and serum were also measured before and after challenge.

RESULTS

Nasal and ocular symptoms were significantly exacerbated after challenge on all days of the single and 3-consecutive-day challenge tests, particularly on the third day of the consecutive challenge test. Nasal and ocular symptoms were also quickly induced with challenge immediately after the end of pollen season. No significant changes in inflammatory markers were seen.

CONCLUSIONS

Care is needed with regard to pollen challenge conditions in the ACC, including timing of the challenge, to induce pollinosis symptoms that accurately reflect chronic inflammation.

Provocation tests as measure of efficacy and dosage

Provocation and challenge tests have been used to understand the pathobiology of asthma, to facilitate diagnosis and to assess therapeutic efficacy and dosage. Current challenge tests expose the patient to 'natural conditions', for example, in an allergen chamber. For determining drug efficacy in asthma, allergen challenge has a moderate positive predictive value and an excellent negative predictive value. The best challenge tests are standardized, and the best bronchial challenge tests use a large allergen particle size. Allergen provocation tests are safe when performed by experienced investigators.

The allergen challenge chamber: a valuable tool for optimizing the clinical development of pollen immunotherapy

The clinical development of allergen immunotherapy for allergic rhinoconjunctivitis because of pollen is complicated by seasonal, geographical and subject-related variability in allergen exposure. Using an allergen challenge chamber (ACC), a room that enables reproducible challenges with controlled levels of inhalant allergens for several hours, these factors can be controlled. The ACC has often been used to evaluate symptomatic medications but is underexploited in the field of allergen immunotherapy. When used in conjunction with a programme of natural-exposure trials, the ACC enables researchers to (i) facilitate the allergen immunotherapy dose-finding process, (ii) accelerate the transition from Phase I/II to Phase III trials, (iii) characterize the onset and maintenance of action, (iv) avoid the confounding effects of rescue medication, (v) better characterize the baseline or pretreatment characteristics of trial subjects, (vi) perform better-standardized physical and laboratory measurements during an acute challenge, (vii) simplify trial logistics and use smaller numbers of subjects than would be required in equivalent natural-exposure studies and (viii) support (but not replace) Phase III natural-exposure trials for the investigation into long-term and disease-modifying effects. ACC studies can further increase levels of evidence for allergen immunotherapy--the only current therapy potentially capable of modifying the underlying allergic disease.

A review of the efficacy of desloratadine, fexofenadine, and levocetirizine in the treatment of nasal congestion in patients with allergic rhinitis

BACKGROUND

Nasal congestion is the most troublesome symptom of allergic rhinitis (AR). First-generation and older second-generation antihistamines, while effective against nasal itching, sneezing, and rhinorrhea, have limited efficacy in relieving nasal congestion.

OBJECTIVE

This review included nasal challenge studies and clinical trials that reported the effects on nasal congestion of the newer second-generation antihistamines desloratadine, fexofenadine, and levocetirizine.

METHODS

MEDLINE and EMBASE were searched for nasal challenge studies and clinical trials published in English between January 1, 1991, and January 31, 2009, using the following terms, alone or in combination: antihistamines, second-generation antihistamines, allergic rhinitis, intermittent allergic rhinitis, perennial allergic rhinitis, persistent allergic rhinitis, seasonal allergic rhinitis, nasal challenge, nasal blockage, and nasal congestion. Studies that were not active or placebo controlled, that did not evaluate change in nasal congestion scores, or that focused on treatments other than desloratadine, fexofenadine, and levocetirizine for nasal congestion associated with AR were excluded.

RESULTS

Twenty-six clinical trials met the criteria for inclusion in the review. In 11 placebo-controlled trials that included objective assessment of nasal congestion, desloratadine, fexofenadine, and levocetirizine were associated with reductions in the severity of nasal congestion through maintenance of nasal airflow. The mean AUC for nasal airflow over 6 hours was significantly greater with desloratadine compared with placebo in 3 studies (P < 0.05); placebo-controlled trials of fexofenadine and levocetirizine had similar results. In 25 placebo- and active-controlled trials that reported subject-rated symptom scores, the 3 newer antihistamines were efficacious in the treatment of nasal congestion associated with AR. In 10 trials that reported objective and/or subjective measures, desloratadine was associated with significant improvements in nasal congestion compared with placebo (P < or = 0.05), beginning as early as the first 2 hours after allergen challenge. Fexofenadine was associated with significantly lower nasal congestion scores compared with placebo in 4 studies (P <- 0.05); nasal congestion scores were significantly reduced with levocetirizine in 3 placebo-controlled trials (P < or = 0.005).

CONCLUSIONS

In the studies reviewed, desloratadine, fexofenadine, and levocetirizine were effective in relieving the nasal congestion associated with AR compared with placebo. This effect began as early as day 2 and was consistent and progressive throughout treatment. Desloratadine, fexofenadine, and levocetirizine are appropriate options for the treatment of nasal congestion in patients with AR.

Efficacy of loratadine-montelukast on nasal congestion in patients with seasonal allergic rhinitis in an environmental exposure unit

BACKGROUND

Nasal congestion is considered to be one of the most bothersome symptoms of allergic rhinitis (AR) and often the most difficult to treat. Oral therapies providing safe, effective, and reliable relief of AR symptoms, including nasal congestion, are limited.

OBJECTIVE

To evaluate the efficacy of a single dose of loratadine-montelukast (10 mg/10 mg) vs placebo and phenylephrine (10 mg) in relieving nasal congestion over 6 hours after ragweed pollen exposure in the environmental exposure unit at the Kingston General Hospital.

METHODS

After a screening visit and up to 6 priming visits, patients who met minimum symptom requirements during ragweed pollen exposure were randomized to receive loratadine-montelukast, phenylephrine, or placebo. Patients evaluated nasal congestion and other symptoms of AR and measured peak nasal inspiratory flow before dosing and at 20-minute intervals during the subsequent 8 hours of pollen exposure.

RESULTS

During the first 6 hours after treatment (primary end point), loratadine-montelukast treatment resulted in greater improvement in the mean nasal congestion score vs placebo (P = .007) and phenylephrine (P < .001). Loratadine-montelukast was more effective than placebo (P < or = .02) and phenylephrine (P < or = .002) in relieving total symptoms, nasal symptoms, and nonnasal symptoms and in improving peak nasal inspiratory flow. There were no statistically significant differences between phenylephrine and placebo for any measures. Fewer patients in the loratadine-montelukast group (3.9%) reported adverse events than in the phenylephrine (7.9%) and placebo (7.1%) groups; most adverse events were mild or moderate.

CONCLUSIONS

Loratadine-montelukast was more effective than placebo and phenylephrine in relieving nasal congestion and other nasal and nonnasal symptoms resulting from ragweed pollen exposure. There was no statistically significant difference between phenylephrine and placebo.

A placebo-controlled study of the nasal decongestant effect of phenylephrine and pseudoephedrine in the Vienna Challenge Chamber

BACKGROUND

Studies on the efficacy of phenylephrine in the treatment of nasal congestion have yielded inconsistent results, notwithstanding its approval for this indication.

OBJECTIVE

To evaluate and compare the decongestant effect of a single dose of phenylephrine to placebo and pseudoephedrine in patients with seasonal allergic rhinitis.

METHODS

This randomized, placebo-controlled, 3-way crossover study evaluated patient-scored nasal congestion, peak nasal inspiratory flow, and rhinomanometry at more than 6 hours in 39 grass-sensitive patients exposed to grass pollen in the Vienna Challenge Chamber. Patients were dosed with immediate-release formulations of phenylephrine, 12 mg, pseudoephedrine, 60 mg, as a control, or placebo.

RESULTS

Phenylephrine was not significantly different from placebo in the primary end point, mean change in nasal congestion score at more than 6 hours (P = .56), whereas pseudoephedrine was significantly more effective than both placebo (P < .01) and phenylephrine (P = .01). Phase 1 results showed a difference between phenylephrine and placebo that was 64% of the difference between pseudoephedrine and placebo, substantially greater than the 17% difference observed for all phases. Carryover bias due to patient recall of the pseudoephedrine effect may have influenced these results. Rhinomanometry and peak nasal inspiratory flow results were consistent with these data. Neither phenylephrine nor pseudoephedrine had an effect on the nonnasal symptoms. No adverse events were reported in this study.

CONCLUSIONS

During a 6-hour observation period, a single dose of pseudoephedrine but not phenylephrine resulted in significant improvement in measures of nasal congestion. Neither phenylephrine nor pseudoephedrine had an effect on nonnasal symptoms.

Non-interventional study comparing treatment satisfaction in patients treated with antihistamines

BACKGROUND AND OBJECTIVE

Allergic rhinitis and urticaria are common allergic disorders that may affect approximately 15% of people at some time in their lives. Antihistamines are the most widely used therapeutic interventions for these disorders but the newer generation agents have differing pharmacokinetic characteristics that may result in different patient satisfaction and preferences. The objective of this study was to investigate patients' and physicians' satisfaction with their current antihistamine treatment for allergic disease.

METHODS

In an observational study, physicians in nine European countries completed questionnaires evaluating 7,274 patients treated with an oral antihistamine. The satisfaction of patients and physicians with the efficacy and tolerability of treatment was rated on a visual analogue scale. In addition, the proportion of patients satisfied with treatment (overall satisfaction) and willing to continue treatment with the same antihistamine were assessed. Safety and tolerability data were also gathered.

RESULTS

The results of this study indicate that modern antihistamines are generally considered effective and well tolerated by patients. In general, levocetirizine scored significantly higher in terms of perception of efficacy, tolerability and overall satisfaction. In terms of tolerability, three-quarters of patients were 'very satisfied' and a further fifth were moderately satisfied with levocetirizine and almost all (95%) were happy to continue treatment. Overall, the most commonly reported adverse event in this study was somnolence, a well known effect of antihistamines. The rate of somnolence in the levocetirizine group (3.8%) was similar to that for fexofenadine (both doses) and desloratadine, two products which are considered to be nonsedating antihistamines, and significantly less than half the rate for cetirizine.

CONCLUSION

Levocetirizine is considered an effective and well tolerated option for treating allergic disease by patients and physicians alike, particularly when the best available effectiveness and tolerability are required.

Fluticasone furoate versus placebo in symptoms of grass-pollen allergic rhinitis induced by exposure in the Vienna Challenge Chamber

OBJECTIVE

The Vienna Challenge Chamber (VCC) offers a controlled and controllable paradigm in which to reproducibly evaluate the efficacy of anti-allergic treatment. The aim of this study was to assess the efficacy of the novel intranasal corticosteroid fluticasone furoate (FF) in the VCC.

METHODS

The single-centre, randomised, double-blind, placebo-controlled, two-period crossover study was conducted in 59 adult males with grass pollen allergic rhinitis (AR). Patients received either Fluticasone furoate 200 mcg once-daily, or placebo intranasally for 8 days. AR symptoms were induced during 4-hour allergen challenges with grass pollen in the VCC at the end of each 8-day treatment period. A first challenge was conducted at 1-5 hours post-dose, followed by a second challenge at 22-26 hours post-dose. The primary endpoint was total nasal symptom score (TNSS; sum of itch, sneeze, rhinorrhoea, obstruction symptoms assessed on a categorical scale of 0-3) weighted mean over 2-5 hours post-dose. Secondary endpoints included: TNSS weighted mean over 23-26 hours post-dose and global symptom score, eye symptom score, nasal secretions and nasal airflow weighted means over 2-5 and 23-26 hours post-dose.

RESULTS

Fluticasone furoate showed consistent attenuation of AR symptoms in both the early and late challenges. Compared with placebo, weighted mean of TNSS was reduced on average by 4.14 point-scores at 2-5 hours post-dose and 3.63 point scores at 23-26 hours post-dose. These positive effects were also seen across all secondary endpoints.

CONCLUSION

An 8-day treatment course of intranasal FF 200 mcg given once-daily statistically significantly reduced symptoms of AR including associated eye symptoms. Statistical significance was declared where the relevant two-sided 95% confidence interval did not contain zero. This positive effect was sustained over 24 hours suggesting that fluticasone furoate could be efficacious as a once daily steroid.