Time to onset and duration of action of the antihistamine bepotastine besilate ophthalmic solutions 1.0% and 1.5% in allergic conjunctivitis: a phase III, single-center, prospective, randomized, double-masked, placebo-controlled, conjunctival allergen challenge assessment in adults and children

Efficacy and Toxicity Evaluation of Bepotastine Besilate 1.5% Preservative-Free Eye Drops Vs Olopatadine Hydrochloride 0.2% Bak-Preserved Eye Drops in Patients with Allergic Conjunctivitis

Purpose

To study the efficacy and toxic effects of bepotastine besilate 1.5% preservative-free (BB-PF) and olopatadine 0.2% BAK-preserved (OL-BAK) drops on the ocular surface of patients with allergic conjunctivitis.

Patients and Methods

Ninety-seven patients with allergic conjunctivitis diagnosis participated in a prospective, multicenter, randomized, double-blind, controlled, parallel-group clinical trial. Patients received either BB-PF (n=48) or OL-BAK (n=49), both administered once daily in the morning. The patients were followed for 60 days. Ocular itching was the primary outcome measure. Secondary outcomes included ocular symptoms, signs, and non-ocular symptoms associated with rhinoconjunctivitis. Conjunctival impression cytology (CIC) was performed to evaluate histopathological changes related to the toxic effects of preservatives.

Results

BB-PF treatment was associated with a 1.30 more probability of diminished ocular itching than OL-BAK (odds ratio (OR)=1.30; 95% CI=(0.96-1.7); p=0.086). No statistically significant differences were found between treatments in the resolution of other ocular symptoms or signs, except for tearing, which was superior in the BB-PF (OR=1.37; 95% (1.26-1.47); p<0.0001). BB-PF was superior in terms of the resolution of rhinorrhea (p=0.040) and nasal itching (p=0.037). After 60 days of treatment, the BB-PF group exhibited 2.0 times higher probability of having a lower Nelson scale score compared to the OL-BAK group (OR=2.00; 95% CI=(1.19-3.34); p=0.010).

Conclusion

Both medications presented a similar efficacy in terms of the resolution of ocular signs and symptoms associated with ocular conjunctivitis. BB-PF is superior in the resolution of non-ocular symptoms and safer for the ocular surface than OL-BAK.

Therapeutic Targets in Allergic Conjunctivitis

Allergic conjunctivitis (AC) is a common condition resulting from exposure to allergens such as pollen, animal dander, or mold. It is typically mediated by allergen-induced crosslinking of immunoglobulin E attached to receptors on primed conjunctival mast cells, which results in mast cell degranulation and histamine release, as well as the release of lipid mediators, cytokines, and chemokines. The clinical result is conjunctival hyperemia, tearing, intense itching, and chemosis. Refractory and chronic cases can result in ocular surface complications that may be vision threatening. Patients who experience even mild forms of this disease report an impact on their quality of life. Current treatment options range from non-pharmacologic therapies to ocular and systemic options. However, to adequately control AC, the use of multiple agents is often required. As such, a precise understanding of the immune mechanisms responsible for this ocular surface inflammation is needed to support ongoing research for potential therapeutic targets such as chemokine receptors, cytokine receptors, non-receptor tyrosine kinases, and integrins. This review utilized several published articles regarding the current therapeutic options to treat AC, as well as the pathological and immune mechanisms relevant to AC. This review will also focus on cellular and molecular targets in AC, with particular emphasis on potential therapeutic agents that can attenuate the pathology and immune mechanisms driven by cells, receptors, and molecules that participate in the immunopathogenesis and immunopathology of AC.

A contemporary look at allergic conjunctivitis

Allergic eye disease is common, yet often overlooked in North America. In the U.S., up to 40% of the population is deemed to be affected and this number is growing. Symptoms and signs of ocular allergy can lead to decreased productivity and negatively impact quality of life (QoL). Various treatment options exist to achieve symptom control. For allergic conjunctivitis, ophthalmic agents include antihistamines, mast cell stabilizers, dual-activity agents, nonsteroidal anti-inflammatory drugs (NSAIDs), steroids and some off-label treatments. Immunotherapy is recommended as a therapeutic option. This review provides a summary of the forms of ocular allergies, with a focus on symptoms and signs, impact on QoL, physical examination, diagnosis and therapeutic options of allergic conjunctivitis. Through multidisciplinary collaborations, a simplified algorithm for the treatment of allergic conjunctivitis is proposed for Canadian clinical practice.

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.

Ocular itch associated with allergic conjunctivitis: latest evidence and clinical management

Allergic conjunctivitis is one of the most common allergic conditions worldwide. Its incidence is increasing due to changing climate, pollution, increased pollen loads, and the subject's heightened immunological sensitivity in response to these environmental changes. The pathophysiology predominantly involves immunoglobulin E-related mast-cell activation, with release of histamine and other mediators contributing to the propagation of the response by calling in other immune cells and further inflammation. This article presents the evolution of ocular allergy treatments, from vasoconstrictors, to antihistamines and mast-cell stabilizers, to the dual-acting agents, as well as corticosteroid and immunomodulatory options. Future targets for allergy treatment are also discussed.

Antihistamines and itch

Histamine is one of the best-characterized pruritogens in humans. It is known to play a role in pruritus associated with urticaria as well as ocular and nasal allergic reactions. Histamine mediates its effect via four receptors. Antihistamines that block the activation of the histamine H₁receptor, H₁R, have been shown to be effective therapeutics for the treatment of pruritus associated with urticaria, allergic rhinitis, and allergic conjunctivitis. However, their efficacy in other pruritic diseases such as atopic dermatitis and psoriasis is limited. The other histamine receptors may also play a role in pruritus, with the exception of the histamine H₂receptor, H₂R. Preclinical evidence indicates that local antagonism of the histamine H₃receptor, H₃R, can induce scratching perhaps via blocking inhibitory neuronal signals. The histamine H₄receptor, H₄R, has received a significant amount of attention as to its role in mediating pruritic signals. Indeed, it has now been shown that a selective H₄R antagonist can inhibit histamine-induced itch in humans. This clinical result, in conjunction with efficacy in various preclinical pruritus models, points to the therapeutic potential of H₄R antagonists for the treatment of pruritus not controlled by antihistamines that target the H₁R.

Ocular itch relief with alcaftadine 0.25% versus olopatadine 0.2% in allergic conjunctivitis: pooled analysis of two multicenter randomized clinical trials

Introduction

The efficacy and safety of the once-daily topical ophthalmic solutions, alcaftadine 0.25% and olopatadine 0.2%, in preventing ocular itching associated with allergic conjunctivitis were evaluated.

Methods

Pooled analysis was conducted of two double-masked, multicenter, active- and placebo-controlled studies using the conjunctival allergen challenge (CAC) model of allergic conjunctivitis. Subjects were randomized 1:1:1 to receive alcaftadine 0.25%, olopatadine 0.2%, or placebo. The primary efficacy measure was subject-evaluated mean ocular itching at 3 min post-CAC and 16 h after treatment instillation. Secondary measures included ocular itching at 5 and 7 min post-CAC. Ocular itch was determined over all time points measured (3, 5, and 7 min) post-CAC and the proportion of subjects with minimal itch (itch score <1) and zero itch (itch score = 0) was also assessed.

Results

A total of 284 subjects were enrolled in the two studies. At 3 min post-CAC and 16 h after treatment instillation, alcaftadine 0.25% achieved a significantly lower mean itch score compared with olopatadine 0.2% (0.50 vs. 0.87, respectively; P = 0.0006). Alcaftadine demonstrated a significantly lower mean itch score over all time points compared with olopatadine (0.68 vs. 0.92, respectively; P = 0.0390); both alcaftadine- and olopatadine-treated subjects achieved significantly lower overall mean ocular itching scores compared with placebo (2.10; P < 0.0001 for both actives). Minimal itch over all time points was reported by 76.1% of alcaftadine-treated subjects compared with 58.1% of olopatadine-treated subjects (P = 0.0121). Treatment with alcaftadine 0.25% and olopatadine 0.2% was safe and well tolerated; no serious adverse events were reported.

Conclusion

Once-daily alcaftadine 0.25% ophthalmic solution demonstrated greater efficacy in prevention of ocular itching compared with olopatadine 0.2% at 3 min post-CAC (primary endpoint), and over all time points, 16 h post-treatment instillation. Alcaftadine and olopatadine both provided effective relief compared with placebo and were generally well tolerated.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-014-0155-3) contains supplementary material, which is available to authorized users.

Treatment of allergic conjunctivitis with bepotastine besilate ophthalmic solution 1.5%

PURPOSE

To examine the pooled per-protocol ocular end points from two conjunctival allergen challenge (CAC) clinical trials of the dual-action antihistamine bepotastine besilate ophthalmic solution (BBOS) 1.5%.

METHODS

Two Phase III, placebo-controlled, double-masked, randomized clinical trials were conducted at a total of six separate centers using the CAC model of allergic conjunctivitis. The same study design was employed for both clinical trials, with subjects randomly assigned to either BBOS 1.5% (n=78) or placebo (n=79) treatment. Each subject received one eye drop of the test agent bilaterally at different study visits 15 minutes, 8 hours, or 16 hours prior to a CAC. Primary ocular end points included changes in ocular itching reported at 3, 5, and 7 minutes and conjunctival hyperemia assessed at 7, 15, and 20 minutes following each CAC. Secondary ocular end points included chemosis as well as episcleral and ciliary hyperemia judged by investigators, and tearing (scored as either absent or present) and eyelid swelling judged by subjects.

RESULTS

A statistically significant reduction in ocular itching was observed for BBOS 1.5% treatment compared to placebo at all time points (P<0.0001), while measures for onset and 8-hour persistence of action also reached clinical significance (ie, ≥1.0 unit difference) at a majority of time points. In addition, a significant reduction in conjunctival hyperemia was achieved at a majority of time points during the onset of action CAC test. Secondary end points were also significantly improved compared to placebo, most prominently for reduced tearing at all study visits and reduced eyelid swelling at the onset of action and 8-hour study visits. Adverse events were generally mild and transient.

CONCLUSION

BBOS 1.5% rapidly reduced CAC-induced ocular itching with duration of effectiveness of at least 8 hours after dosing. Certain secondary signs of inflammation were also significantly reduced.

Allergic conjunctivitis: an update on diagnosis and management

PURPOSE OF REVIEW

The focus of this review is to provide a logical paradigm for the diagnosis and treatment of ocular allergies, with a focus on seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC).

RECENT FINDINGS

Several classes of topical medications are currently available for the management of ocular allergies, including: lubricating agents, vasoconstrictors, antihistamines, mast cell stabilizers, and topical corticosteroids.

SUMMARY

SAC and PAC make up the vast majority of ocular allergy cases. A proactive approach to these diseases, anticipating the regional spring and fall allergen spikes, is needed for optimally managing these disorders. A multifaceted treatment regimen comprising patient education, lifestyle modification, and topical medications (such as antihistamines and/or mast cell stabilizers and corticosteroids) may be required in order to manage ocular allergies effectively. The appropriate treatment paradigm is based on the severity of the patients' signs and symptoms. For moderate-to-severe cases, especially chronic vernal keratoconjunctivitis, atopic keratoconjunctivitis, and giant papillary conjunctivitis, comanagement with an ophthalmologist is recommended.

Bepotastine besilate for the treatment of pruritus

INTRODUCTION

Bepotastine besilate 1.5% is a newly approved second-generation topical antihistamine indicated for the pruritus associated with allergic conjunctivitis. In Japan, the oral formulation is approved to manage pruritus associated with allergic rhinitis and urticaria.

AREAS COVERED

Bepotastine is a piperidine derivative that antagonizes H1 receptors with high selectivity. It has been labeled a dual-acting or multiple-acting antiallergic medication, because it inhibits histamine at H1 receptors and stabilizes mast cells to prevent histamine release. Bepotastine may also have other immunoactive properties, such as inhibition of eosinophil migration, interleukin-5 (IL-5), leukotrienes (e.g., LTB4) and platelet-activating factor (PAF). Human clinical trials demonstrate the efficacy and safety of systemic and ophthalmic bepotastine for pruritus relief, limited penetration across the blood-brain-barrier and kinetics suitable for twice-daily administration.

EXPERT OPINION

Bepotastine besilate 1.5% ophthalmic solution is a safe and effective treatment option for allergic conjunctivitis associated pruritus. Side-effect profile is similar to other ocular antihistamine agents. Additional comparative-effectiveness studies would further advance its clinical use. Oral bepotastine is a safe and effective treatment option approved in Japan for allergic rhinitis, urticaria and pruritus associated with skin diseases.

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.

Levocetirizine inhibits migration of immune cells to lymph nodes and induces treg cells in a murine type I allergic conjunctivitis model

Background & Purpose:

Levocetirizine is a histamine H(1) receptor antagonist. Here, we utilised DO11.10TCR transgenic mice to establish an antigen-specific T cell-dependent allergic conjunctivitis (AC) model to determine the effect of the topical application of an ophthalmic formulation of Levoceritizine as a treatment for AC.

Experimental Approach:

DO11.10 mice (n=6/each) were exposed to ovalbumin (OVA, 50 µg) and treated with a Levocetirizine ophthalmic formulation (0.001–0.02% v/w) or placebo (vehicle) for 24–72 h. Serum, aqueous/vitreous humour and conjunctiva were obtained. Immunoglobulin (Ig)-E, interleukin (IL)-10 and lipoxin (LX)A₄ were determined by ELISA. Levels of tumour necrosis factor (TNF)-α, transforming growth factor (TGF)-β, interferon (IFN)-γ and 18rS expression were measured by RT-PCR. Proportions of total and activated antigen-presenting cells (APC), recruited T lymphocytes (CD4+), activated T lymphocytes (CD25+) and T regulatory cells (Treg) were measured by flow cytometry.

Key Results:

OVA exposure induced AC in the animal model indicated by increased expression of LXA₄, TNF-α and TGF-β. Levocetirizine treatment (0.01–0.02% v/w) reduced LXA₄ in the eye humours. This treatment approach increased systemic IL-10 secretion and reduced TNF-α and TGF-β expression in conjunctiva without changing IFN-γ expression. Levocetirizine reduced APC levels in draining lymph nodes but increased the proportion of total lymphocytes recruited and their differentiation to Treg cells.

Conclusions & Implications:

Levocetirizine effectively reduces the activation and migration of APC to local draining lymph nodes and induces differentiation of Treg cells as one possible mechanism of its anti-inflammatory action.

Comparative efficacy of bepotastine besilate 1.5% ophthalmic solution versus olopatadine hydrochloride 0.2% ophthalmic solution evaluated by patient preference

BACKGROUND

The aim of this study was to compare patient-perceived relief of ocular itch, nasal symptoms, and eye drop comfort when allergic conjunctivitis was treated with bepotastine besilate 1.5% versus olopatadine hydrochloride 0.2%.

METHODS

This randomized, observer-masked, single-center, crossover study included 30 patients with ocular itching associated with allergic conjunctivitis accompanied by nasal symptoms. Patients were treated with bepotastine besilate 1.5% twice daily (7 am and 4 pm) or olopatadine hydrochloride 0.2% once daily (7 am) for 14 days. Following a 7-day washout period during which only preservative-free artificial tears were used twice daily, patients were crossed over to the alternative treatment for 14 days. Parameters evaluated by twice-daily patient diaries included each treatment's ability to relieve ocular itch, ability to relieve itchy/runny nose, ability to relieve ocular allergy symptoms, and eye drop comfort. At the conclusion of the study, patients were also asked to identify which agent provided better all-day relief of ocular itching, better all-day relief of itchy/runny nose, superior comfort, and for which treatment they would prefer a prescription.

RESULTS

According to the mean daily diary responses, bepotastine besilate 1.5% provided significantly better relief of evening ocular itch, relief of morning and evening itchy/runny nose, and relief of morning and evening ocular allergy symptoms. At study end, 63.3% and 66.7% of patients preferred bepotastine besilate 1.5% for all-day relief of ocular itching and all-day relief of itchy/runny nose, respectively. At study end, there was no significant difference in the number of patients preferring one treatment over the other for comfort. Overall, 66.7% of patients stated that they would prefer to treat their allergic conjunctivitis with bepotastine besilate 1.5% over olopatadine hydrochloride 0.2%.

CONCLUSION

Based on their evaluation of therapeutic performance, patients preferred bepotastine besilate 1.5% over olopatadine hydrochloride 0.2% by two-to-one for the treatment of allergic conjunctivitis.

Bepotastine besilate ophthalmic solution for the relief of nonocular symptoms provoked by conjunctival allergen challenge

BACKGROUND

Bepotastine besilate is a selective histamine1-receptor antagonist and mast cell stabilizer with inhibitory effects on eosinophilic activity.

OBJECTIVE

To evaluate the safety and efficacy of 1.5% bepotastine besilate ophthalmic solution in alleviating nonocular symptoms induced by a conjunctival allergen challenge (CAC), a clinical model of allergic conjunctivitis.

METHODS

This was a single-center, double-masked, randomized, placebo-controlled clinical trial performed from March 1 to April 4, 2007. Patients 10 years or older with a history of allergic conjunctivitis and a reproducible, positive, clinical response to a CAC were eligible. Patients received either placebo or 1.5% bepotastine besilate, 1 drop in each eye. After 15 minutes, 8 hours, or 16 hours after dosing, a CAC was performed and patients evaluated nonocular symptoms using standardized grading scales.

RESULTS

Seventy-one patients were enrolled in the study, and 66 comprised the per protocol population. A clinically meaningful reduction (> or = 1.0 unit) compared to placebo was achieved for rhinorrhea and nasal congestion at most time points after 1.5% bepotastine besilate instillation at 8 hours before a CAC test. Significant reductions (P < or = .05) in mean values were seen with 1.5% bepotastine besilate at 15 minutes and 8 hours after dosing for CAC-induced nasal congestion, rhinorrhea, ear or palate pruritus, nasal pruritus, and summed nonocular composite symptom (NOCS) scores and also at 16 hours after dosing for nasal congestion and rhinorrhea.

CONCLUSIONS

The 1.5% bepotastine besilate formulation produced statistically significant reductions after a CAC in individual nonocular symptoms and NOCS scores at onset of allergic response and for at least 8 hours after instillation, with the greatest reduction seen for nasal congestion and rhinorrhea.

Allergic conjunctivitis and the impact of allergic rhinitis

Although nasal allergy has been prominent in allergy research, ocular allergy is increasingly recognized as a distinct symptom complex that imposes its own disease burden and reduction in patients' quality of life. In the past year, knowledge of the relationships between allergic conjunctivitis and allergic rhinitis has increased. Allergic conjunctivitis is highly prevalent and has a close epidemiologic relationship with allergic rhinitis. Both conditions also exhibit similar pathophysiologic mechanisms. Pathways of communication are thought to increase the likelihood of an inflammatory reaction at both sites following allergen exposure of nasal or ocular tissue. Clinical trials of intranasal therapies have demonstrated efficacy in allergic conjunctivitis and rhinitis. Newer intranasal steroids decrease ocular symptoms, potentially achieving efficacy by suppressing the naso-ocular reflex, downregulation of inflammatory cell expression, or restoration of nasolacrimal duct patency. Proposed pathophysiologic interactions between allergic rhinitis and ocular allergy underscore the need for therapies with efficacy in both symptom sets.

Multicenter clinical evaluation of bepotastine besilate ophthalmic solutions 1.0% and 1.5% to treat allergic conjunctivitis

PURPOSE

To evaluate the effectiveness of bepotastine besilate ophthalmic solutions 1.0% and 1.5% compared with placebo at reducing ocular itching and conjunctival hyperemia in the conjunctival allergen challenge (CAC) model of allergic conjunctivitis.

DESIGN

Prospective, double-masked, randomized, placebo-controlled, phase 3 CAC clinical trial.

METHODS

This multicenter trial enrolled 130 subjects with a clinical history of allergic conjunctivitis who were randomized to bepotastine besilate ophthalmic solution 1.0%, 1.5%, or 0.0% (placebo). One drop of test agent was instilled bilaterally before a CAC test evaluating responses at 15 minutes, 8 hours, or 16 hours after test agent instillation. Primary efficacy outcomes were unit improvements relative to placebo in mean scores for ocular itching and conjunctival hyperemia, each graded on 0- to 4-unit scales.

RESULTS

Reductions of 1.2 units or more in mean ocular itching scores at all time points for both bepotastine besilate ophthalmic solutions 1.0% and 1.5% were observed at onset of action and 8-hour duration-of-action CAC tests (P < .0001). Statistically significant reductions in conjunctival hyperemia (P < or = .0125) were observed for bepotastine besilate ophthalmic formulations only at the onset of action CAC test.

CONCLUSIONS

Bepotastine besilate ophthalmic solutions 1.0% and 1.5% both substantially decreased CAC-induced ocular itching for at least 8 hours after dosing. Reductions in conjunctival hyperemia after a CAC, although statistically significant for bepotastine besilate ophthalmic solutions 1.0% and 1.5% compared with placebo when assessed at 15 minutes after dosing, were modest.

Bepotastine besilate, a highly selective histamine H(1) receptor antagonist, suppresses vascular hyperpermeability and eosinophil recruitment in in vitro and in vivo experimental allergic conjunctivitis models

To elucidate the ocular pharmacological properties of bepotastine besilate, a selective histamine H(1) receptor antagonist, when compared with other histamine H(1) receptor antagonists, using guinea pig allergic conjunctivitis models and in vitro models of eosinophil recruitment and mast cell membrane stabilization. Conjunctival vascular hyperpermeability was studied in guinea pigs passively sensitized with anti-ovalbumin antiserum or following subconjunctival injection of histamine. Modulation of eosinophil recruitment was evaluated for both platelet-activating factor (PAF)-induced eosinophil infiltration in guinea pigs and leukotriene B(4)-induced in vitro chemotaxis of guinea pig peritoneal eosinophils. Membrane-stabilizing effects of bepotastine also were studied with rat peritoneal mast cells stimulated with the ionophore A23187. Histamine H(1) receptor antagonists including bepotastine besilate were topically administered before ovalbumin, histamine or PAF challenges for in vivo experiments or were added directly to mast cell and eosinophil medium in vitro. Bepotastine besilate significantly inhibited conjunctival vascular hyperpermeability in a dose-dependent manner with maximal effect for bepotastine besilate 1.5%. In separate in vivo experiments, bepotastine besilate 1.0% was significantly more effective than levocabastine 0.025% in the passive sensitization model or olopatadine 0.1% in the histamine-induced hyperpermeability model. Bepotastine besilate 1.0% further suppressed PAF-induced eosinophil infiltration into conjunctival tissue more effectively than ketotifen 0.05%. Chemotaxis of guinea pig peritoneal eosinophils and histamine release from rat peritoneal mast cells in vitro were also inhibited by addition of bepotastine. Olopatadine had a weak effect as compared to that of bepotastine on eosinophil chemotaxis and no effect on mast cell histamine release in our study conditions. Bepotastine besilate was more potent than olopatadine, ketotifen, or levocabastine in reducing vascular hyperpermeability in various animal models of allergic conjunctivitis. Mast cell function and eosinophil chemotaxis were also inhibited in vitro with bepotastine, suggesting bepotastine acts as an inhibitor of allergic response through multiple mechanisms: histamine H(1) receptor antagonism, mast cell stabilization, and inhibition of eosinophil migration to ocular inflammatory sites.