A comparative trial of the safety and efficacy of 0.1 percent pemirolast potassium ophthalmic solution dosed twice or four times a day in patients with seasonal allergic conjunctivitis.

PURPOSE To compare efficacy and safety between twice-daily and four-times-daily regimens of pemirolast 0.1% in allergic conjunctivitis patients. METHODS This investigator-masked trial recruited 169 patients, with a positive skin prick test, +2 itching and hyperemia. Patients were randomized to two times daily (t.i.d.) or four times daily (q.i.d.) treatment during allergy season. Evaluation was at 0, 2 and 4 weeks, with itching and hyperemia at week 4 as the primary endpoints. Analysis used last observation carried forward (LOCF) and analysis of variance (ANOVA) for efficacy, factoring treatment and center variations. The basis of the statistical evaluation was to confirm parity between two treatments, via noninferiority hypothesis testing. A 95% confidence interval (CI) with an upper limit of < or = 0.5 was set to assess non-inferiority or to conclude if schedules were statistically similar. RESULTS B.i.d. and q.i.d. baselines were similar, respectively, for itching (2.6 and 2.8) and hyperemia (2.3 and 2.2). Week 4 itching was statistically non-inferior between treatments (1 b.i.d. versus 0.8 q.i.d.), with a mean treatment difference of 0.17 (-0.13, 0.47, Delta < or = 0.5). Week 4 hyperemia was comparable (1.2 for b.i.d. versus 1.0 for q.i.d). Week 2 scores and mean change from baseline (weeks 2 and 4), patient diary data, and investigator assessments were comparable. Both regimens were well tolerated with no differences in adverse events were observed. CONCLUSIONS B.i.d. dosing was statistically non-inferior to q.i.d. dosing with respect to itching and hyperemia. Both regimens were similarly well tolerated in allergic conjunctivitis patients.