Efficacy of olopatadine versus epinastine for treating allergic conjunctivitis caused by Japanese cedar pollen: a double-blind randomized controlled trial.

INTRODUCTION: The objective of this study was to compare the efficacy and safety of olopatadine versus epinastine in healthy Japanese adults with a history of allergic conjunctivitis to Japanese cedar pollen. METHODS: This Phase IV double-blind randomized controlled clinical trial comprised three clinical visits over 30 days. Screening tests were performed to identify subjects with a history of allergic conjunctivitis to Japanese cedar pollen in terms of skin sensitivity and positive bilateral reactions to a conjunctival allergen challenge (CAC) with Japanese cedar pollen at Visit 1, and confirmation by a positive bilateral CAC reaction at Visit 2. At Visit 3, the subjects were randomized to receive one drop of olopatadine HCl ophthalmic solution 0.1% (olopatadine) in the left or right eye (1:1 ratio). All subjects received one drop of epinastine HCl ophthalmic solution 0.05% (epinastine) in the contralateral eye as an active control. Five min later, the subjects underwent bilateral CAC tests with one drop of the allergen solution at the concentration that elicited positive reactions at Visits 1 and 2. Efficacy outcomes included the severity of ocular itching at 5, 7, and 15 min and the severity of conjunctival hyperemia at 7, 15, and 20 min after the CAC test, as graded by the investigator by biomicroscopy. RESULTS: Fifty people participated in this study (25 per group). Olopatadine significantly reduced ocular itching at 7 and 15 min (both p<0.05) and conjunctival hyperemia at 7 and 20 min (p=0.0010 and p<0.05, respectively) after allergen exposure compared with epinastine. There were no adverse events for either treatment. CONCLUSION: The results of this single-dose study suggest that olopatadine is superior to epinastine in terms of suppressing ocular itching and hyperemia induced by Japanese cedar pollen during CAC tests. Further studies are needed to confirm these findings in real-life settings.

Efficacy of epinastine hydrochloride ophthalmic solution in allergic conjunctivitis by conjunctival cedar pollen allergen challenge.

BACKGROUND: Epinastine hydrochloride is a selective histamine H1 receptor antagonist that also inhibits IgE receptor-mediated histamine release from mast cells. OBJECTIVE: To show the superiority of epinastine 0.05% ophthalmic solution (epinastine) to placebo ophthalmic solution (placebo) and noninferiority to olopatadine 0.1% ophthalmic solution (olopatadine) for cedar pollen antigen-induced ocular itching and conjunctival hyperemia. METHODS: The study was conducted in ophthalmologically asymptomatic adult volunteers with seasonal allergic conjunctivitis using a conjunctival allergen challenge test. Subjects were randomized into 3 groups (n = 87) to evaluate superiority to placebo (visits 4 to 6) and 2 groups (n = 86) to evaluate noninferiority to olopatadine (visit 7). At each visit, a single administration of the study medication was instilled at 15 minutes (visit 4), 4 hours (visit 5), 8 hours (visit 6), and 4 hours (visit 7) before the conjunctival allergen challenge test. Ocular itching and conjunctival hyperemia of allergic conjunctivitis were assessed after the conjunctival allergen challenge test. RESULTS: For the primary end point, epinastine showed superiority to placebo for the inhibition of ocular itching and conjunctival hyperemia induced at 4 hours after the dose (equivalent to 4-times-daily dosing). For the secondary end points, epinastine significantly inhibited itching and conjunctival hyperemia induced at 15 minutes and 8 hours after the dose (equivalent to 2-times-daily dosing) compared with placebo. In addition, epinastine demonstrated noninferiority to olopatadine for ocular itching and conjunctival hyperemia. No adverse drug reactions or serious adverse events were reported throughout the study, indicating that epinastine has a good safety profile. CONCLUSION: Epinastine is effective and safe for the treatment of allergic conjunctivitis. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT01363700.