Comparison of the clinical efficacy and comfort of olopatadine hydrochloride 0.1% ophthalmic solution and nedocromil sodium 2% ophthalmic solution in the human conjunctival allergen challenge model.
BACKGROUND
Mast cell stabilizers, such as the ocular antiallergic agent nedocromil sodium 2% ophthalmic solution, are not rapid acting and often require a loading period of > or =2 weeks for maximal efficacy. Olopatadine hydrochloride 0.1% ophthalmic solution is a member of a new class of topical antiallergic agents that have combined antihistaminic and mast cell-stabilizing properties.


OBJECTIVE
The purpose of this study was to compare the clinical efficacy and comfort of olopatadine with those of nedocromil in the conjunctival allergen challenge model.


METHODS
This was a single-center, 3-visit, randomized, double-masked, contralaterally controlled study. Seventy-five subjects with a history of allergic conjunctivitis were screened, and the 52 who responded to conjunctival allergen challenge at visits I and 2 were randomized by eye to receive olopatadine, nedocromil, or placebo (a "natural tears" lubricant eye drop). Because nedocromil may require a 2-week loading period for maximal efficacy, the eyes assigned to that agent received nedocromil for 14 days (between visits 2 and 3), whereas the eyes assigned to olopatadine or placebo received placebo during this period. Throughout the loading phase, subjects instilled 1 drop of the assigned masked medication in each eye twice daily. At the assessment visit (visit 3), subjects received I drop of masked olopatadine, nedocromil, or placebo in each eye and were asked to rate the comfort of each drop on a scale from 0 to 8. Fifteen minutes after instillation of medication, subjects were challenged with the allergen concentration that had elicited a positive conjunctival allergic response at the previous visits. Subjects then scored their itching on a scale from 0 to 4 at 3, 5, and 10 minutes after challenge. Mean itching scores for all eyes were compared by treatment. Paired t tests were performed on the mean itching and ocular comfort scores at each time point. At the end of the study, subjects were asked which treatment they preferred in terms of comfort and efficacy.


RESULTS
Forty-nine subjects completed the study. Forty eyes received olopatadine, 36 received nedocromil, and 22 received placebo. Olopatadine was clinically and statistically superior to nedocromil at reducing itching in the conjunctival allergen challenge model (mean unit difference: -1.60 at 3 minutes, -1.68 at 5 minutes, -1.19 at 10 minutes; P < 0.001). One drop of olopatadine was more efficacious than 29 drops of nedocromil. Olopatadine-treated eyes were rated as being significantly more comfortable than nedocromil-treated eyes (0.73 vs 1.55; P = 0.034). Of the 14 subjects treated with olopatadine and nedocromil who stated a preference, 10 (71%) were more satisfied with olopatadine than with nedocromil.


CONCLUSIONS
In the conjunctival allergen challenge model, olopatadine was more efficacious and comfortable than nedocromil in reducing the itching associated with allergic conjunctivitis.
Butrus
S
S
Ophthalmology, Georgetown University School of Medicine, Washington, DC, USA.
Greiner
J V
JV
Discepola
M
M
Finegold
I
I
D003233:Conjunctivitis, Allergic / Q000188:drug therapy*; D003990:Dibenzoxepins / Q000627:therapeutic use*; D004311:Double-Blind Method; D006801:Humans; D017835:Nedocromil / Q000627:therapeutic use*; D000069605:Olopatadine Hydrochloride; D009883:Ophthalmic Solutions / Q000627:therapeutic use*; D017060:Patient Satisfaction; D010919:Placebos
D003990:Dibenzoxepins; D009883:Ophthalmic Solutions; D010919:Placebos; D017835:Nedocromil; D000069605:Olopatadine Hydrochloride