A placebo-controlled comparison of ketotifen fumarate and nedocromil sodium ophthalmic solutions for the prevention of ocular itching with the conjunctival allergen challenge model

Abstract

Background: Ketotifen fumarate 0.025% ophthalmic solution and nedocromil sodium 2.0% ophthalmic solution are 2 topical antiallergic medications with different modes of action and efficacy profiles. Both solutions are indicated for ocular itching associated with allergic conjunctivitis. Objective: This study compared the efficacy, safety, and comfort of ketotifen fumarate 0.025% ophthalmic solution and nedocromil sodium 2.0% ophthalmic solution for the prevention of ocular itching, using the conjunctival allergen challenge (CAC) model. Methods: This was a single-center, double-masked, contralateral, randomized, placebo- and active-controlled CAC clinical trial. Subjects aged >10 years with a history of allergic hypersensitivity who responded to the CAC at screening visits 1 and 2 qualified for randomization at visit 3. At visit 3 (day 21) and visit 4 (day 35), subjects received 1 of 3 treatments: ketotifen, nedocromil, or placebo (artificial tears), randomized by eye. Allergen challenges were conducted at 5 minutes posttreatment dose (visit 3) and 12 hours posttreatment dose (visit 4). At each visit, subjects evaluated their ocular itching every 30 seconds for 20 minutes. At visit 4, subjects evaluated the comfort of the medication immediately after instillation, at 30 seconds after instillation, and at l, 2, 5, and 10 minutes after instillation. The subjects were also queried about overall eyedrop comfort by choosing from descriptive terms and about overall eyedrop preference based on comfort and perceived efficacy. Results: Eighty-five subjects were screened for this study. Fifty-nine (28 males, 31 females; mean age, 38.7 years) qualified and were randomized to receive study medications. Ketotifen-treated eyes experienced significantly less ocular itching induced by CAC than nedocromil-treated eyes and those that received placebo at both the 5-minute and 12-hour posttreatment allergen challenges (all P < 0.05). Nedocromil-treated eyes showed no statistical or clinical differences from placebo at any time point. Ketotifen-treated eyes showed no differences in comfort from those that received placebo but were significantly more comfortable than nedocromil-treated eyes at 1, 2, 5, and 10 minutes after instillation (all P < 0.05). On the basis of comfort and subjective efficacy, 60% of subjects preferred ketotifen, 21% preferred nedocromil, and 19% preferred placebo. Conclusion: Ketotifen was significantly more effective and comfortable than nedocromil at both 5 minutes and 12 hours after administration in this CAC model.