A comparison of the relative clinical efficacy of a single dose of ketotifen fumarate 0.025% ophthalmic solution versus placebo in inhibiting the signs and symptoms of allergic rhinoconjunctivitis as induced by the conjunctival allergen challenge model

Abstract

Background: Ketotifen fumarate 0.025% ophthalmic solution is an antiallergic treatment currently available in the United States. It is indicated for the temporary prevention of ocular itching due to allergic conjunctivitis. Objective: The purpose of this study was to determine the relative efficacy of ketotifen when applied topically to the eye, compared with placebo, in the treatment of nasal signs and symptoms of allergic rhinoconjunctivitis as induced by the conjunctival allergen challenge (CAC) model. Methods: This was a randomized, double-blind, parallel-group, single-center clinical study using the CAC model. Patients aged ≥ 18 years, able to follow the study instructions, willing to avoid disallowed medications, and having a history of rhinoconjunctivitis and a positive skin test were eligible. At visit 1, the dose of allergen necessary to achieve a qualifying reaction was determined using bilateral ocular instillation of allergen to eligible patients. At visit 2, the allergen dose determined at visit 1 was confirmed, and all patients attaining a qualifying nasal reaction continued in the study. At visit 3, each patient was randomized to receive 1 drop of ketotifen bilaterally in the eyes or 1 drop of placebo bilaterally. Fifteen minutes after instillation of the study medication, bilateral CAC was performed. Patients rated nasal symptoms (sneezing, rhinorrhea and postnasal drip, nasal pruritus, palatal pruritus, and nasal congestion) on standardized scales at 10, 20, and 30 minutes after CAC. Results: Thirty-two patients (16 men, 16 women; mean age, 45 years [range, 28–70 years]) were randomized to treatment and completed the study. Nineteen patients received ketotifen and 13 received placebo. Nasal symptom scores in ketotifen-treated patients were statistically and clinically significantly fewer than in those treated with placebo at all time points (mean baseline corrected total nasal score: 10 minutes, P = 0.010; 20 minutes, P = 0.025; 30 minutes, P = 0.006). Conclusion: In this study, topical ketotifen fumarate 0.025% ophthalmic solution, when dosed ocularly, offered protection against the nasal signs and symptoms of acute allergic rhinoconjunctival reaction as induced by the CAC model.