Original articleInterventionsEfficacy of epinastine hydrochloride ophthalmic solution in allergic conjunctivitis by conjunctival cedar pollen allergen challenge
Introduction
Seasonal allergic conjunctivitis is the most common allergic disease and affects millions of people worldwide. Regarding the underlying mechanism, degranulation of mast cells leads to the local release of inflammatory chemical mediators in the conjunctiva.1 In this regard, the roles of mast cell stabilizers and H1 blockers as topical therapeutic regimens have been extensively explored for the past 2 decades.
In general, environmental and conjunctival allergen challenge (CAC) studies are performed primarily for the clinical evaluation of antiallergic ophthalmic solutions. In environmental studies, the efficacy of antiallergic ophthalmic solutions has been evaluated in trials using natural exposure, such as during the pollen season. However, that model has an inherent drawback of different exposures between seasons and individuals.2 Conversely, CAC studies use a defined exposure that can be adjusted for individuals with regard to the allergen exposure rate.[2], [3], [4], [5] As models that allow for appropriate clinical assessment of allergic conjunctivitis, CAC studies have been used in the United States, Europe, Japan, and other countries.[6], [7], [8]
Epinastine hydrochloride is a topical ocular antihistamine that exhibits strong binding to histamine H1 receptors and has potent anti-inflammatory properties resulting from the inhibition of the release of mediators, such as histamine and leukotriene, and the decrease of the downstream effects of leukotriene C4, platelet-activating factor, serotonin, and other factors.[9], [10], [11], [12] The authors conducted a phase III CAC study of epinastine hydrochloride 0.05% ophthalmic solution (epinastine) using an allergen solution of cedar pollen, the most widely dispersed pollen species in Japan.
Section snippets
Subjects
Adult volunteers with a history of seasonal allergic conjunctivitis and cedar pollen-specific IgE were selected. Subjects had to be asymptomatic, with no ocular itching or conjunctival hyperemia, before the allergen challenge. The main exclusion criteria included complications of extraocular or anterior ocular segment inflammatory disease or dry eye, a Schirmer test reaction no larger than 5 mm, recent (<90 days) intraocular surgery, or recent (<30 days) treatment for lacrimal punctum
Baseline Characteristics
Table 2 lists the baseline characteristics of the subjects in the full analysis set. One subject in group B (Epi/Epi) was withdrawn from the study after the completion of visit 5 because the subject had difficulty with the schedule. There was no intergroup bias in any of the background characteristics.
Ocular itching
The primary end points of the mean ocular itching scores (mean ± SE) for the 3 time points after allergen challenge at 4 hours were 0.4 ± 0.1 and 1.7 ± 0.1 for epinastine and placebo, respectively
Discussion
During the annual cedar pollen season in Japan, many patients develop seasonal allergic conjunctivitis with intense ocular itching and have significant impairment in their quality of life. Although the estimated prevalence of allergic conjunctival disease is approximately 15% to 20%,1 increasing numbers of patients are developing cedar pollinosis, and the disease is a major public health problem in Japan because of its intense symptoms, high prevalence, poor spontaneous recovery rate, and
Acknowledgment
The authors thank the principal investigator, Dr Hiroshi Nakatani at the Kitasato University Kitasato Institute Hospital Biomedical Research Center.
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Cited by (20)
Executive summary: Japanese guidelines for allergic conjunctival diseases 2021
2022, Allergology InternationalFabrication and characterization of disposable stencil printed ion selective electrode with improved sensitivity for determination of antiallergic epinastine HCl in opthalmic solution
2021, Measurement: Journal of the International Measurement ConfederationCitation Excerpt :Epinastine hydrochloride (Fig. 1) is a strong selective histamine H1 receptor used for the treatment of allergic conjunctivitis [1], and is chemically known as 3-Amino-9,13b-dihydro-1H-dibenz[c,f]imidazo[1,5-a]azepine hydrochloride, Allergic conjunctivitis is a prevalent seasonal disease caused by a particular allergic reaction between the eye and seasonal allergens [2].
Short-term exposure to air pollution and conjunctivitis outpatient visits: A multi-city study in China
2019, Environmental PollutionCitation Excerpt :It's estimated that conjunctivitis accounts for 1% of all primary care and emergency room visits (Azari and Barney, 2013). The contributory role of air pollution on conjunctivitis has received attention lately, including epidemiological studies on air pollution and conjunctivitis prevalence in developing countries and mechanism studies exploring the conjunctival inflammatory response after exposure to automobile exhaust (Rosario et al., 2018; Brandt et al., 2013; Fujishima et al., 2014). The rapid industrialization and urbanization of China might be a contributing factor to the prevalence of conjunctivitis in this region.
Evaluating the efficacy of epinastine ophthalmic solution using a conjunctivitis allergen challenge model in patients with birch pollen allergic conjunctivitis
2017, Allergology InternationalCitation Excerpt :Epinastine has both effects of antihistamine properties, blocking the histamine 1 (H1) receptor,4 and chemical mediator stabilizer properties, inhibiting the release of mediators, including histamine and leukotrienes.5,6 A phase III study demonstrated that epinastine 0.05% ophthalmic solution was effective in suppressing SAC symptoms in patients in a conjunctival allergen challenge (CAC) test using an allergen solution of cedar pollen.7 To our knowledge, the efficacy of epinastine 0.05% ophthalmic solution in treating SAC caused by other antigens has not been studied.
Efficacy and safety of an eye wash solution in allergic conjunctivitis after conjunctival allergen challenge
2016, Annals of Allergy, Asthma and Immunology
Disclosure: Drs Fujishima, Ohashi, and Takamura have consulted for Santen Pharmaceutical Co Ltd.
Funding: This study was sponsored and funded by Santen Pharmaceutical Co Ltd, Osaka, Japan.