[Double-masked, phase III comparative study of the combination ophthalmic solution of the 1% dorzolamide hydrochloride/0.5% timolol maleate (MK-0507A) in patients with glaucoma and ocular hypertension].

OBJECTIVE: To investigate the IOP-lowering effect and safety of a combined ophthalmic solution (MK-0507A) of 1% dorzolamide hydrochloride and 0.5% timolol maleate in comparison to 0.5% timolol maleate (timolol), and 1% dorzolamide hydrochloride and 0.5% timolol maleate concomitant therapy (concomitant therapy). SUBJECTS AND METHODS: This study was conducted in patients with either primary open angle glaucoma or ocular hypertension. The patients with IOP > or = 18 mmHg following the administration of timolol for 4 weeks during the observation period (474 patients) were randomized to receive either MK-0507A (189 patients), timolol (92 patients) or concomitant therapy (193 patients) during the treatment period and when evaluated for IOP at Week 8. The primary evaluation criteria were change in 2 hour IOP from baseline to Week 8. RESULTS: The least square means of the changes in hour 2 IOP from baseline to Week 8 were -2.50 mmHg, -1.82 mmHg and -2.78 mmHg in the MK-0507 A group, timolol group and concomitant therapy group, respectively. MK-0507A demonstrated a significant reduction in IOP compared to timolol. Further- more, the 95% confidence interval of the difference between MK-0507A and concomitant groups satisfied the pre-specified criteria for non-inferiority confirming the non-inferiority of MK-0507A relative to the concomitant therapy. In addition, MK-0507A had safety comparable to that of timolol and concomitant therapy. CONCLUSION: MK-0507A has a significantly superior IOP-lowering effect relative to timolol. MK-0507A also showed a non-inferior IOP-lowering effect relative to the concomitant therapy. MK-0507A was safe compared to both timolol and concomitant therapy.