Dr. Blaiss analyzed combined data on 85 patients participating in two prospective, randomized, double-masked bilateral CAC studies. The analysis was another way of looking at the data that should be helpful to clinicians, he noted.
"It tells us more about how this drug works in the real world," said Dr. Blaiss, clinical professor of pediatrics and medicine, University of Tennes see Health Science Center, Memphis. The data also support FDA labeling for once-daily dosing, because significantly more olopatadine-treated patients than those in the placebo group reported no ocular itching 16 hours after treatment.
Dr. Blaiss reviewed data on both onset and duration of action in two studies used to support the FDA's approval of olopatadine. In those studies, patients received olopatadine in one eye and placebo in the other and then assessed ocular itching on a scale of 0 (none) to 4 (severe). Those with a score of at least 2 were challenged with antigen 27 minutes after dosing for the assessment of onset of action. They were challenged again at 16 hours after dosing for the duration of action assessment. In addition, the percentage of patients with zero itch in both studies was assessed at 3 minutes after the allergen challenge.
After the onset of action allergen challenge, 60 % of the eyes treated with olopatadine had zero itch at the 3-minute timepoint, compared with 5.9% for the vehicle-treated eyes (p <0.0001).
At 3 minutes post-allergen challenge following 16-hour dosing, 59.8% of the olopatadine-treated eyes had zero itch, compared with 22% of eyes treated with placebo (p < 0.0001)
Dr. Blaiss is a consultant for Alcon Laboratories.