Background: Olopatadine hydrochloride 0.1% ophthalmic solution and loteprednol etabonate 0.2% ophthalmic suspension are topical antiallergic agents indicated for treatment of the signs and symptoms of allergic conjunctivitis and seasonal allergic conjunctivitis (SAC), respectively.
Objective: The purpose of this study was to compare the efficacy and tolerability of olopatadine, loteprednol, and placebo in inhibiting the early-phase allergic reaction (within 30 minutes) after conjunctival allergen challenge (CAC).
Methods: This was a single-center, randomized, double-masked, parallel-controlled CAC study. It consisted of 3 visits, with CAC performed at visit 1, confirmation and randomization at visit 2, and evaluation of the treatments at visit 3. Subjects with a history of allergic conjunctivitis were randomized to receive olopatadine, loteprednol, or placebo in a 2:2:1 ratio. Because loteprednol requires a loading period to achieve maximum efficacy, subjects assigned to this treatment received loteprednol QID bilaterally for a 14-day period; the olopatadine and placebo groups received placebo QID bilaterally during this period. At the evaluation visit, subjects received 1 drop of the assigned treatment in each eye. Fifteen minutes later, they were challenged with allergen. Subjects evaluated itching at 3, 5, and 10 minutes after challenge using a standardized 5-point scale; the investigator evaluated redness at 10, 15, and 20 minutes after challenge. Intraocular pressure (IOP) was measured at baseline and after the 14-day loading period. Nonparametric analyses were performed on the change from visit 2 to visit 3 in mean itching and redness scores for each time point, and on the change in mean IOP from visit 1 to visit 3.
Results: Fifty subjects (86% white; 42% male, 58% female; age range, 21-71 years) were enrolled and completed the study (20 olopatadine, 20 loteprednol, 10 placebo). The allergens to which subjects reacted were ragweed pollen (40%), cat hair or dander (30%), grass pollen (24%), and tree pollen (6%). The difference in inhibition of itching and redness was clinically significant (> or =1 unit difference) and statistically significant (P < 0.05) in favor of olopatadine compared with loteprednol at all 3 time points. The loteprednol group had a statistically significant increase in IOP after 2 weeks of treatment (P < 0.001).
Conclusion: In the population studied, olopatadine was more efficacious than loteprednol in reducing the acute signs and symptoms of SAC during the early phase of the ocular allergic reaction and appeared to be better tolerated.