Organ-specific allergen challenges in airway allergy: Current utilities and future directions.

Atopy has been long used as the screening method for airway allergy. Nevertheless, aeroallergens can trigger respiratory symptoms not only in atopic patients (atopic respiratory allergy, ARA), but also in non-atopic subjects (local respiratory allergy, LRA). Moreover, ARA and LRA can coexist in the same patient, and this clinical scenario has been called dual respiratory allergy (DRA). When the clinical history cannot determine the relevance of sensitizations in ARA patients, nasal, conjunctival or bronchial allergen challenges (NAC, CAC, and BAC, respectively) should be conducted. Moreover, these tests are required to identify patients with LRA and DRA. The clarification of the allergic triggers of airway diseases has a profound impact on the management strategies the patients can be offered. Importantly, allergen immunotherapy (AIT) remains as the only disease-modifying intervention for ARA. Recent data indicate that AIT might have a similar effect on LRA patients. Nevertheless, AIT success relies largely on the correct phenotyping of allergic individuals, and NAC, CAC, and BAC are very helpful tools in this regard. In this review, we will summarize the main indications and methodology of CAC, NAC, and BAC. Importantly, the clinical implementation of these tests might translate into precision medicine approaches and better health outcomes for patients with airway allergy.

Birch allergen challenges in allergic conjunctivitis using standard conjunctival allergen challenge and environmental exposure chamber.

BACKGROUND: Environmental exposure chambers (EECs) have been used extensively to study allergic rhinoconjunctivitis. Few studies have been published using EECs in conjunctivitis only, and none have used conjunctival allergen challenge as a selection criterion. The present study validated ALYATEC EEC in allergic conjunctivitis to birch pollen. METHODS: Sixteen patients with a positive conjunctival allergen challenge (CAC) were exposed to 60 ng/m3 of Bet v 1 in an EEC on two consecutive days for a maximum of 4 h to validate EEC exposure to birch. Reproducibility was tested among seven of the patients. A conjunctival positive scoring during the CAC and the EEC exposure was defined as a Total Ocular Symptom Score (TOSS) ≥ 5. RESULTS: Fifty percent of patients had a conjunctival positive scoring during first exposure and 75% during second exposure. The mean time to a conjunctival response was 81.2 ± 33.9 min and 101.6 ± 57 (P > 0.05) during first and second exposure, respectively. No difference in TOSS occurred between the two exposures. The time necessary to obtain a positive response during the CAC was significantly shorter than with the EEC. The estimated quantity of Bet v 1 inducing a positive response was 0.07 ± 0.03 ng (exposure 1), 0.07 ± 0.07 ng (exposure 2), 980 ± 784 ng (CAC). Conjunctival positive scoring and quantity of Bet v 1 was reproducible in all six EEC exposures. CONCLUSIONS: Early conjunctival responses induced by birch allergen exposures in EEC were different than from those identified with direct instillation during CAC. EEC appears to be closer to natural exposure than CAC.

Alcaftadine 0.25% versus Olopatadine 0.1% in Preventing Cedar Pollen Allergic Conjunctivitis in Japan: A Randomized Study.

Purpose: To compare alcaftadine and olopatadine ophthalmic solutions, and vehicle for preventing allergen-mediated conjunctivitis in Japanese subjects. Methods: Japanese cedar pollen-sensitive subjects were randomized to alcaftadine 0.25%, olopatadine 0.1%, or vehicle. Ocular itching was assessed at 3, 5 (primary outcome), 7, and 15 min post-conjunctival allergen challenge (CAC) and conjunctival hyperemia assessed at 7, 15 (secondary outcome), and 20 min post-CAC. Adverse events were monitored. Results: Overall, 240 subjects were randomized. Alcaftadine 0.25% (challenged 8 h post-dose) was significantly more effective than vehicle for prevention of itching and conjunctival hyperemia (p < 0.001) and noninferior to olopatadine 0.1% (challenged 4 h post-dose). Significantly lower hyperemia scores were observed in alcaftadine-treated than olopatadine-treated eyes at 7 and 15 min post-CAC (p ≤ 0.027). Alcaftadine and olopatadine were well tolerated; no serious adverse events were reported. Conclusion: Alcaftadine 0.25% is effective in preventing signs and symptoms of Japanese cedar pollen-induced allergic conjunctivitis.

Early nonreactivity in the conjunctival provocation test predicts beneficial outcome of sublingual immunotherapy.

BACKGROUND: Clinical practice needs a common parameter that can provide an early, reliable estimation of the outcome of sublingual immunotherapy (SLIT) in an upcoming pollen season. We investigated whether the conjunctival provocation test (CPT) can predict the beneficial outcome of SLIT in patients with allergic rhinoconjunctivitis after 4 weeks of treatment. METHODS: We conducted two separate prospective, randomized, double-blind, placebo-controlled, multicenter trials. Adults 18-75 years of age received placebo or SLIT tablets containing tree or grass pollen allergoids and underwent CPTs. Participants receiving SLIT were divided into two groups (reactive, nonreactive) according to their CPT reactions after 4 weeks of treatment. These two groups were compared with regard to clinical outcome parameters (total combined score, rhinoconjunctivitis total symptom score, total rescue medication score, well days) assessed during the pollen season for the 14-day (tree) or 30-day (tree/grass) peaks and for the entire 60-day seasons. Participants' global evaluations of therapy after completing treatment were also compared. RESULTS: The tree pollen trial randomized 188 participants; 182 participants were evaluable, 76 of whom received SLIT and were suitable for this post hoc analysis. The grass pollen trial included 90 participants; 82 participants were evaluable, 44 of whom underwent SLIT. Comparing SLIT participants who reacted to the CPT after 4 weeks (tree: 77.6%; grass: 79.5%) with those who ceased to show a reaction (tree: 22.4%; grass: 20.5%) (tree: P = 0.0001; grass: P = 0.003), the total combined score for the 14-day (P = 0.017) and 30-day peaks (P = 0.042) as well as the rhinoconjunctivitis total symptom score assessed for the 14-day peak (P = 0.024) were significantly lower in the nonreactive group of the tree pollen trial. In the grass pollen trial, the nonreactive group rated their SLIT treatment significantly better (P = 0.019). CONCLUSIONS: Using clinically meaningful outcome parameters during the pollen season, both trials independently led to similar results when comparing participants' reactions to the CPT 4 weeks after beginning SLIT. These results suggest that CPT allows an early estimation of allergic rhinoconjunctivitis symptoms before an upcoming season. Thus, the CPT can be used as a valuable parameter to predict the beneficial outcome of ongoing SLIT. TRIAL REGISTRATION: Both trials registered with the Medical Ethics Committee of the North Rhine Medical Council (EudraCT numbers 2012-004916-79 (grass pollen trial) and 2013-002129-43 (tree pollen trial)) and the German Federal Ministry of Health (Paul-Ehrlich-Institut).

Bepotastine besilate ophthalmic solution 1.5% for alleviating nasal symptoms in patients with allergic conjunctivitis.

BACKGROUND: Bepotastine besilate ophthalmic solution (BBOS) 1.5% is a topical antihistamine for the treatment of ocular itching associated with allergic conjunctivitis (AC). Allergic rhinitis and AC are common comorbid conditions. We explored the efficacy of BBOS 1.5% in alleviating nasal symptoms in an integrated analysis of two Phase III conjunctival allergen challenge (CAC) studies and a Phase IV environmental allergen study. METHODS: In the Phase III trials, a CAC was performed 15 minutes, 8 hours, and 16 hours following ocular instillation of BBOS 1.5% (n=78) or placebo (n=79), and subjects evaluated nasal symptoms. In the environmental study, subjects instilled BBOS 1.5% (n=123) or placebo (n=122) twice daily and nasal symptoms were evaluated over 2 weeks. RESULTS: In the Phase III trials, BBOS 1.5% had reduced CAC-induced nasal congestion and pruritus at 15 minutes and 8 hours postdosing and rhinorrhea and a non-ocular composite-symptom score (sum of nasal scores plus ear or palate pruritus) at all time points postdosing (all P≤0.01 vs placebo). In the Phase IV environmental study, BBOS 1.5% reduced sneezing and nasal pruritus over 2 weeks and median number of days to improvement of nasal pruritus and total nasal symptom score (sum for rhinorrhea, sneezing, nasal pruritus, and nasal congestion; P≤0.04 vs placebo). Additionally, investigator-reported improvement in overall ocular (pruritus, hyperemia, tearing) and nasal symptoms was greater with BBOS 1.5% vs placebo (P≤0.03). CONCLUSION: Results of these exploratory analyses indicate that topical ocular BBOS 1.5% reduced nasal symptoms, supporting its use for alleviating rhinitis symptoms associated with AC.

Pooled analysis of two studies evaluating efficacy and safety of olopatadine hydrochloride 0.77% in patients with allergic conjunctivitis.

PURPOSE: Two individual phase 3 conjunctival allergen challenge (CAC) studies of similar design have assessed the efficacy and safety of olopatadine hydrochloride (HCl) 0.77% for the treatment of allergic conjunctivitis. The purpose of this study is to evaluate the integrated efficacy and safety of olopatadine HCl 0.77% from a larger dataset by pooling data from the two individual CAC studies. METHODS: Data were pooled from two phase 3, randomized, multicenter, double-masked, active- and vehicle-controlled CAC studies. The primary comparison was on ocular itching scores between olopatadine HCl 0.77% versus vehicle (at onset and 24 hours) and olopatadine HCl 0.77% versus olopatadine 0.2% (at 24 hours). Additional end points included conjunctival redness, total redness, and proportion of itching responders at onset and 24-hour duration of CAC. For both primary and secondary analysis, mixed model repeated measures analysis was used, except for proportion of ocular itching responders. Sensitivity analyses were carried out using a two-sample t-test. RESULTS: This analysis included 448 patients. Olopatadine HCl 0.77% was superior to vehicle (P<0.0001) at onset and 24-hour duration of action (difference in means: -1.14 to -1.52) and to olopatadine 0.2% (P=0.0009) at 24-hour duration of action in relieving ocular itch. Additionally, olopatadine HCl 0.77% substantially reduced conjunctival redness and total redness over vehicle and olopatadine 0.2% at onset and 24-hour duration of action. At 24 hours CAC, there were a higher proportion of itching responders with olopatadine HCl 0.77% compared to vehicle or olopatadine 0.2% (difference in proportion of responders: 43.17%, P<0.0001, and 17.25%, P=0.0012, respectively). No safety concerns were identified. CONCLUSION: This analysis confirms the findings from the individual studies. The rapid onset and prolonged duration of action (for 24 hours) of olopatadine HCl 0.77% supports once-daily dosing in the treatment of allergic conjunctivitis.

Evaluating the efficacy of epinastine ophthalmic solution using a conjunctivitis allergen challenge model in patients with birch pollen allergic conjunctivitis.

BACKGROUND: The efficacy of epinastine 0.05% ophthalmic solution for pollen allergic conjunctivitis has already been shown in a conjunctival allergen challenge (CAC) test using cedar pollen as a challenge. The present study investigated the efficacy of this solution against birch pollen conjunctivitis in a CAC test. METHODS: Ten adult subjects (eight males and two females) with asymptomatic birch pollen conjunctivitis were enrolled in this study. The average age of the subjects was 41.1 years. This study was conducted during a period without birch pollen dispersion. In each subject, the epinastine 0.05% ophthalmic solution was instilled in one eye, and an artificial tear fluid was instilled in the fellow eye in a double-blind manner. Five minutes or 4 h after the drug instillation, both eyes were challenged with an optimal concentration of birch pollen, and ocular itching and conjunctival hyperemia were then graded. Tears were collected before the drug instillation and 20 min after the pollen challenge, and the histamine level was measured. RESULTS: The ocular itching scores and palpebral conjunctival hyperemia scores of the epinastine-treated eyes were significantly lower than those of the contralateral control eyes when the eyes were pretreated with the drug 4 h before the CAC. There was a significant correlation between the tear histamine level and mean ocular itching score of three time points (3, 5 and 10 min) following the CAC in the control eyes but not the epinastine-treated eyes. CONCLUSIONS: Epinastine is effective in suppressing ocular itching and conjunctival hyperemia in birch pollen conjunctivitis.

Efficacy and safety of olopatadine hydrochloride 0.77% in patients with allergic conjunctivitis using a conjunctival allergen-challenge model.

BACKGROUND: Symptom relief for the duration of 24 hours after treatment would benefit patients with allergic conjunctivitis. OBJECTIVE: To compare the safety and efficacy of olopatadine 0.77% with vehicle or olopatadine 0.2% in patients with allergic conjunctivitis in a conjunctival allergen-challenge clinical study. PATIENTS AND METHODS: In this Phase III, multicenter, double-masked, parallel-group, randomized trial, patients with allergic conjunctivitis received olopatadine 0.77%, its vehicle, or olopatadine 0.2%, administered once at visits 3A (day 0), 4A (day 14 ±2), and 5 (day 21 +3). Allergic conjunctivitis-associated sign and symptom assessments included ocular itching, conjunctival redness, total redness, chemosis, and tearing scores. Adverse events and ocular safety parameters were also assessed. RESULTS: A total of 202 qualifying patients were randomized. Olopatadine 0.77% was superior (P<0.001) to vehicle for treatment of ocular itching at 3, 5, and 7 minutes postchallenge at onset of action and 16- and 24-hour duration of action. Conjunctival redness mean scores were significantly lower for olopatadine 0.77% versus vehicle at all three post-conjunctival allergen-challenge time points: onset (-1.52 to -1.48; P<0.001), 16 hours (-1.50 to -1.38; P<0.01), and 24 hours (-1.58 to -1.38; P<0.05). At 24 hours, olopatadine 0.77% was superior to olopatadine 0.2% at all three postchallenge time points for ocular itching (P<0.05), conjunctival redness (P<0.05), and total redness (P<0.05). No clinically relevant differences in safety parameters or adverse events were observed between the treatment groups. CONCLUSION: Olopatadine 0.77% is superior to both its vehicle and olopatadine 0.2% for the treatment of allergen-mediated ocular itching and conjunctival redness. Ocular itching symptom relief is maintained over 24 hours, supporting once-daily dosing and demonstrating a comparable safety profile to olopatadine 0.2%.

Effect of alcaftadine 0.25% on ocular itch associated with seasonal or perennial allergic conjunctivitis: a pooled analysis of two multicenter randomized clinical trials.

PURPOSE: Seasonal and perennial allergic conjunctivitis represent the majority of cases of ocular allergy. This analysis was designed to evaluate the efficacy and safety of once-daily alcaftadine 0.25% in preventing ocular itching associated with seasonal or perennial allergic conjunctivitis. SUBJECTS AND METHODS: Pooled data from two double-masked, multicenter, placebo-controlled studies using the conjunctival allergen challenge (CAC) model of allergic conjunctivitis were analyzed. Subjects randomized to receive treatment with alcaftadine 0.25% or placebo were challenged with seasonal (grass, ragweed, trees) or perennial (cat dander, cat hair, dog dander, dust mites, cockroach) allergens, 16 hours after treatment instillation. The primary efficacy measure was subject-evaluated mean ocular itching at 3 minutes post-CAC. Secondary measures included ocular itching at 5 and 7 minutes post-CAC. The proportion of subjects with minimal itch (itch score <1) and zero itch (itch score =0), and safety were also assessed. RESULTS: A total of 189 subjects enrolled in the two studies were treated with alcaftadine or placebo. Overall, 129 subjects were challenged with seasonal allergens and 60 subjects were challenged with perennial allergens. Alcaftadine 0.25% achieved a statistically significant reduction in mean itch score at 3, 5, and 7 minutes post-CAC compared with placebo in subjects challenged with seasonal allergens (P<0.0001 at all time points) and those challenged with perennial allergens (P<0.0001 at all time points). A higher percentage of subjects treated with alcaftadine compared with placebo achieved minimal itch (P≤0.001 versus placebo at all time points) and zero itch (P<0.05 at all time points except 7 minutes for perennial) when challenged with either seasonal or perennial allergens. No treatment-related or serious adverse events were reported. CONCLUSION: Once-daily alcaftadine 0.25% ophthalmic solution was well tolerated and demonstrated effective relief of ocular itching in subjects challenged with allergens classic for triggering either seasonal or perennial allergic conjunctivitis.

Conjunctival provocation tests: a predictive factor for patients' seasonal allergic rhinoconjunctivitis symptoms.

BACKGROUND: No parameters currently exist that can reliably predict the impact of preseasonal immunotherapy on the symptoms occurring during the season. OBJECTIVE: The purpose of our studies was to prove a correlation between preseasonal conjunctival allergen challenge and coseasonal primary clinical endpoints using the total combined score, ie, a combination of symptoms and medication score, as the primary outcome parameter. METHODS: Twelve weeks before both the birch and the grass pollen seasons, 2 separate prospective, double-blind, randomized, controlled studies were conducted followed by posttrial observations for each study during the active season. In the studies, patients who reacted to conjunctival allergen challenge were treated with sublingual immunotherapy tablets that contain either birch and/or alder or grass pollen allergoids. RESULTS: In all, 158 patients were included in the grass and 160 in the tree pollen study; of these, 100 and 109 patients, respectively, took part in the posttrial observations. When comparing patients with and without a positive reaction in the final conjunctival allergen challenge, the results revealed a significant difference in the total combined score (grass: P < .001; birch: P = .025). The same applied to the rescue medication score (P = .005; P = .025). A significant difference regarding the rhinoconjunctivitis symptom score was shown in the grass pollen study (P = .002), and the difference of well days was significant in the tree pollen study (P = .049). CONCLUSION: When comparing patients based on their reaction to allergen challenge after immunotherapy, each study leads to similarly significant results. Therefore, conjunctival allergen challenge can be used effectively as a parameter to predict allergic rhinoconjunctivitis symptoms during the season in patients treated with preseasonal sublingual immunotherapy tablets. Whether this can be transferred to untreated patients needs to be determined.

A multicenter evaluation of the efficacy and duration of action of alcaftadine 0.25% and olopatadine 0.2% in the conjunctival allergen challenge model.

BACKGROUND: The purpose of this study was to evaluate the efficacy and duration of action of once-daily dosing with alcaftadine 0.25% ophthalmic solution and olopatadine 0.2% ophthalmic solution as compared with placebo in the prevention of ocular itching, and to directly compare the efficacy of alcaftadine 0.25% with olopatadine 0.2% in the prevention of ocular itching associated with allergic conjunctivitis using the conjunctival allergen challenge model. METHODS: Subjects with allergic conjunctivitis (n = 127) were enrolled in a multicenter, double-masked, randomized, active-controlled and placebo-controlled clinical trial. Using the conjunctival allergen challenge model, this study was conducted over the course of approximately 5 weeks. Subjects were randomized into one of three treatment arms: alcaftadine 0.25% ophthalmic solution, olopatadine 0.2% ophthalmic solution, or placebo. Study medications were administered twice over the course of the trial. The primary efficacy measure for the study was ocular itching evaluated by the subject at 3, 5, and 7 minutes post challenge. Secondary endpoints, measured at 7, 15, and 20 minutes post challenge, included conjunctival, ciliary, and episcleral redness, lid swelling, chemosis, and tearing. Duration of action was measured at 16 and 24 hours post-instillation of the study medication at visits 3 and 4, respectively. RESULTS: For the primary measure of ocular itching, both actives, alcaftadine 0.25% and olopatadine 0.2%, were statistically superior to placebo at all three measured time points for both the 16-hour and 24-hour measures (P < 0.0001). Eyes treated with alcaftadine 0.25% had numerically lower mean ocular itching scores than eyes treated with olopatadine 0.2% at every time point, and this difference was statistically significant at the 3-minute time point 16 hours post instillation (P = 0.026). Eyes treated with alcaftadine 0.25% and with olopatadine 0.2% displayed significantly less lid swelling relative to placebo at every time point for the 16-hour and 24-hour post-instillation visits (P < 0.005). Alcaftadine 0.25% was the only active treatment that provided statistically significant relief of chemosis at every time point of the 24-hour post-instillation visit. CONCLUSION: Both the alcaftadine 0.25% and olopatadine 0.2% ophthalmic solutions provided highly effective relief of ocular itching at both 16 and 24 hours post-instillation. Treatment differences between the actives were most pronounced at the earliest time point (3 minutes post-challenge) following conjunctival allergen challenge (16 hours), when alcaftadine 0.25% ophthalmic solution was statistically superior to olopatadine 0.2% ophthalmic solution. Alcaftadine 0.25% was the only treatment to provide significant relief from chemosis at both 16 and 24 hours post-instillation. Both active treatments and placebo were generally safe and well tolerated.

Exacerbation of signs and symptoms of allergic conjunctivitis by a controlled adverse environment challenge in subjects with a history of dry eye and ocular allergy.

BACKGROUND: The goal of this study was to assess the effect of a controlled adverse environment (CAE) challenge on subjects with both allergic conjunctivitis and dry eye. METHODS: Thirty-three subjects were screened and 17 completed this institutional review board-approved study. Subjects underwent baseline ocular assessments and conjunctival allergen challenge (CAC) on days 0 and 3. Those who met the ocular redness and itching criteria were randomized to receive either the controlled adverse environment (CAE) challenge (group A, n = 9) or no challenge (group B, n = 8) at day 6. Thirty minutes after CAE/no-CAE, subjects were challenged with allergen and their signs and symptoms graded. Exploratory confocal microscopy was carried out in a subset of subjects at hourly intervals for 5 hours post-CAC on days 3 and 6. RESULTS: Seven minutes post-CAC, subjects exposed to the CAE had significantly greater itching (difference between groups, 0.55 ± 0.25, P = 0.028), conjunctival redness (0.59 ± 0.19, P = 0.002), episcleral redness (0.56 ± 0.19, P = 0.003) and mean overall redness (mean of conjunctival, episcleral, and ciliary redness, 0.59 ± 0.14, P < 0.001). The mean score at 7, 15, and 20 minutes post-CAC for conjunctival redness (0.43 ± 0.17, P = 0.012), episcleral redness (0.49 ± 0.15, P = 0.001), mean overall redness in all regions (0.43 ± 0.15, P = 0.005), and mean chemosis (0.20 ± 0.08, P = 0.017) were also all significantly greater in CAE-treated subjects. Confocal microscopic images of conjunctival vessels after CAC showed more inflammation in CAE-treated subjects. CONCLUSION: In subjects with both dry eye and allergic conjunctivitis, exposure to adverse environmental conditions causes an ocular surface perturbation that can intensify allergic reactions.

Evaluation of alcaftadine 0.25% ophthalmic solution in acute allergic conjunctivitis at 15 minutes and 16 hours after instillation versus placebo and olopatadine 0.1%.

PURPOSE: To evaluate the effectiveness of alcaftadine 0.05%, 0.1%, and 0.25% ophthalmic solutions in treating the signs and symptoms of allergic conjunctivitis when compared with olopatadine hydrochloride 0.1% and placebo using the conjunctival allergen challenge (CAC) model. METHODS: One hundred and seventy subjects were randomized and 164 subjects completed all visits. CAC was performed to determine and confirm subjects' eligibility at visits 1 and 2, respectively. The CAC was repeated at visit 3 (day 0 ± 3), 16 hours after study medication instillation, and at visit 4 (day 14 ± 3), 15 minutes after instillation. Ocular itching and conjunctival redness were evaluated after an allergen challenge, along with several secondary endpoints. RESULTS: Alcaftadine 0.25% and olopatadine 0.1% treatments exhibited significantly lower mean scores compared with placebo for ocular itching and conjunctival redness at visits 3 and 4. Most adverse events were self-limiting and mild in severity. No serious treatment-related adverse events occurred. CONCLUSION: Treatment with alcaftadine 0.25% ophthalmic solution resulted in mean differences of >1 unit (ocular itching) and approximately >1 unit (conjunctival redness), which was significant (P < 0.001) compared with placebo treatment. All doses of alcaftadine were safe and well tolerated in the population studied.