Methods: This multinational, prospective, randomized study comprised 316 patients with mild to moderate primary open angle glaucoma. For an eye to be eligible the IOP had to be less than or equal to 21 mmHg on current dual therapy, where one agent was a topical beta-blocker. A total of 240 patients discontinued current therapy and received latanoprost monotherapy while 76 patients continued on current dual therapy for 3 months. The primary endpoint was the proportion of patients who succeeded in reaching the following IOP criteria after 3 months on latanoprost: diurnal IOP of less or equal than 22 mm Hg and with an increase in diurnal IOP from baseline of 15% or less.

Results: Fifteen patients receiving latanoprost were withdrawn from the study, 8 patients due to adverse events, 5 patients for non-medical reasons, and 2 patients due to uncontrolled IOP. Of the remaining 225 patients who completed the study period and including patients withdrawn due to uncontrolled IOP, 91% succeeded in reaching the predefined IOP criteria. For those patients who remained on dual therapy, a comparable success rate of 93% was observed. Replacement of dual therapy with latanoprost resulted in a mean IOP change of - 0.8 mm from a mean diurnal IOP of 17.9 mmHg. A mean IOP change of - 0.2 mmHg from a mean diurnal IOP of 17.2 mmHg was found in patients who continued on current dual therapy.