luation of olopatadine 0.2% in the complete prevention of ocular itching in the conjunctival allergen challenge model Original Research (2362) Total Article Views Authors: Kabat AG, Granet DB, Amin D, Tort MJ, Blaiss MS Published Date July 2011 Volume 2011:3 Pages 57 - 62 DOI: http://dx.doi.org/10.2147/OPTO.S21181 Alan G Kabat1, David B Granet2, Dina Amin3, Maria J Tort3, Michael S Blaiss4 1Nova Southeastern University, Fort Lauderdale, FL, USA; 2Shiley Eye Center, University of California San Diego, La Jolla, CA, USA; 3Alcon Research Ltd, Fort Worth, TX, USA; 4University of Tennessee Health Science Center, Memphis, TN, USA Background: Olopatadine hydrochloride ophthalmic solution 0.2% (PATADAY ; Alcon, Fort Worth, TX) (olopatadine 0.2%) is a formulation of a multi-action agent that has been approved for the treatment of ocular itching associated with allergic conjunctivitis when used once daily. Objective: To evaluate olopatadine 0.2% versus its vehicle in the complete prevention of ocular itching in adult patients with allergic conjunctivitis. Methods: This paper presents a post-hoc analysis of subgroup results from a single-center, double-masked, randomized, contralateral eye, conjunctival allergen challenge study. The post-hoc efficacy analysis, conducted with data from patients who instilled olopatadine 0.2% in a single eye and vehicle in the contralateral eye, compared the ability of each study formulation to completely prevent ocular itching at three assessment time points post-instillation. Safety was not reevaluated in the post-hoc analysis. Results: Overall, 40 patients received contralateral instillations of study drug and were included in the post-hoc analysis. At all three post-instillation time points, significantly greater proportions of patients reported itching scores of 0 in the olopatadine 0.2%-treated eye than in the vehicle-treated eye (63%–65% versus 3%–10%, respectively; P < 0.05 for each comparison). Within the previously reported results for the full study, no clinically relevant or statistically significant changes from baseline were observed for patients in regard to visual acuity, ocular signs, or fundus parameters. Conclusion: Olopatadine 0.2% is safe, well tolerated, and superior to vehicle in completely preventing ocular itching that results from allergen exposure following drug instillation in patients with allergic conjunctivitis.