Patients with
allergic conjunctivitis may experience several debilitating symptoms, particularly ocular
itching. The objective of this study was to evaluate the efficacy and safety of
pemirolast potassium 0.1%
ophthalmic solution (
Alamast trade mark ), a novel
mast-cell stabilizer, for preventing ocular manifestations of seasonal
allergic conjunctivitis. A pooled analysis was performed of data derived from 2 prospective, randomized, double-masked, placebo-controlled, multicenter phase III clinical trials of
pemirolast potassium 0.1% in patients with a history of
allergic conjunctivitis. Patients having a positive bilateral response to conjunctival
allergen challenge (CAC) with ragweed
antigen (N = 274) were randomized to receive
pemirolast potassium 0.1% or placebo QID, beginning approximately 1-2 weeks before the onset of ragweed season and continuing until after the first killing frost (12-17 weeks duration). Patients recorded their daily evaluations of ocular
itching in a diary. After the
allergy season, patients underwent a second CAC. Evaluable patients (n = 265) recorded a total of 21,491 patient-days of ocular
itching data during
allergy season. In every 7-day or 14-day period, patients treated with
pemirolast potassium 0.1% reported more days without any ocular
itching compared with patients receiving placebo. Differences favoring
pemirolast potassium 0.1% were statistically significant in 63% (10/16) of all 7-day periods (p < or = 0.046) and 88% (7/8) of all 14-day periods (p < or = 0.016). After the
allergy season,
pemirolast potassium 0.1% was significantly superior to placebo in relieving CAC-induced ocular
itching, with relief occurring as early as 3 minutes after
allergen challenge (p < or = 0.034).
Pemirolast potassium 0.1% was well tolerated and had a safety profile similar to that of placebo. In conclusion,
pemirolast potassium 0.1% is effective and safe in preventing ocular
itching in patients with
allergic conjunctivitis during
allergy season.