Evaluation of 0.05% Levocabastine versus 4% Sodium Cromolyn in the Allergen Challenge Model

Purpose: This study was conducted to evaluate the efficacy of 0.05% levocabastine compared with 4% Cromolyn for treating allergic conjunctivitis induced by ocular allergen challenge. Methods: Subjects who met all entry criteria and reacted positively to ocular allergen challenge at two previous visits (n = 50) received placebo in one eye and Cromolyn in the fellow eye, four times daily for 2 weeks. On day 18, subjects received the final dose of Cromolyn in the pretreated eye and one drop of levocabastine in the fellow eye. Subjects were challenged and evaluated after 3, 5, and 10 minutes. Four hours after drug administration, subjects were rechallenged and evaluated after 3, 5, and 10 minutes. Results: Levocabastine was significantly more effective than Cromolyn in inhibiting itching, hyperemia, eyelid swelling, chemosis, and tearing after the initial challenge and 4-hour rechallenge (P < 0.05). Conclusion: These results suggest that levocabastine is superior to Cromolyn for treating allergen-induced conjunctivitis and has a duration of action of at least 4 hours.