Elimination of ocular itching by olopatadine HCl ophthalmic solution, 0.2%

Background: The goal of this placebo-controlled evaluation was to assess the ability of olopatadine HCl ophthalmic solution, 0.2%, to eliminate ocular itching associated with allergen-mediated conjunctivitis in a conjunctival allergen challenge (CAC) model.

Method: The study was a randomized, double-masked trial of subjects who had a history of allergic response to cat hair/dander, ragweed, dust mites, grasses, and/or trees. Subjects were asked to rate their ocular itching on a scale of 0 to 4 in increments of 0.5, with 0 = none and 4 = severe. All subjects were required to have zero itching bilaterally (both scores = 0) at baseline. This analysis focused on a subset of 40 subjects who were dosed in one eye with olopatadine 0.2% and in the contralateral eye with placebo. Eligible subjects were challenged with antigen at 27 minutes after dosing with drug or placebo. This post hoc efficacy analysis evaluated the ability of the drug to reduce itching scores to zero.. The safety analysis was based on an evaluation of the exposure to study drug, adverse events, visual acuity, ocular signs, and fundus parameters.

Results: The 40 subjects had an average age of 39 ± 11 years; 65% were women and 35% were men. At 3 minutes after the antigen challenge, 63% of subjects (25 of 40) reported having zero itching in their olopatadine-treated eyes, while only 3% of subjects (1 of 40) reported having zero itching in their placebo-treated eyes. At 5 minutes after the antigen challenge, 63% of subjects (25 of 40) reported having zero itching in their olopatadine-treated eyes, while only 5% of subjects (2 of 40) reported zero itch in their placebo-treated eyes. At 7 minutes after the antigen challenge, 65% of subjects (26 of 40) reported zero itch in their olopatadine-treated eyes, while only 10% of subjects (4 of 40) reported zero itch in their placebo-treated eyes. The percentages of eyes with zero itch scores were significantly higher in the olopatadine group than in the placebo group at every time point (p < 0.05). No treatment-related adverse events were reported during the study.

Conclusion: In this placebo-controlled, contralateral-designed, double-masked conjunctival antigen challenge study, olopatadine HCl ophthalmic solution 0.2% prevented any allergen-induced ocular itching response in a majority of eyes. The percentages of eyes with zero itch scores were significantly higher in the olopatadine group than in the placebo group at every analysis time point.