Efficacy of the dorzolamide/timolol fixed combination versus latanoprost in the treatment of ocular hypertension or glaucoma: combined analysis of pooled data from two large randomized observer and patient-masked studies.

In previous analyses of primary efficacy data from two randomized clinical trials, standard dosing regimens of the dorzolamide/timolol fixed combination (COSOPT) and latanoprost (XALATAN) were shown to have equivalent efficacy with regard to reduction in mean daytime diurnal intraocular pressure (IOP). We performed additional post hoc analyses of pooled data from these studies to compare further the efficacy of the two treatments. The studies used identical 3-month, parallel group, randomized, observer-masked and patient-masked, multicenter designs. Patients with a baseline IOP > or = 24 mm Hg were randomized to either the 2% dorzolamide/0.5% timolol combination eye drops twice daily (n = 273) or 0.005% latanoprost eye drops once daily (n = 271). The IOP measurements were made at 8 AM, 10 AM, 2 PM, and 4 PM at the baseline visit and then on each of the 3 monthly assessment days. The following measures were analyzed on a post hoc basis: 1) percentages of patients meeting target levels of IOP reduction; 2) mean IOP reduction in those patients with high IOP (> or =30 mmHg) at baseline; 3) mean IOP at each of the assessment time points during a day. A total of 259 patients in the dorzolamide/timolol group and 268 patients in the latanoprost group were included in the efficacy analysis. At 3 months, both treatments showed similar efficacy with regard to the percentages of patients who achieved target levels of IOP reduction (e.g., 40% IOP reduction in 15% of dorzolamide/timolol combination patients and 13% of latanoprost patients), mean IOP reduction in those patients with high IOP at baseline (dorzolamide/ timolol combination, 12.5 mmHg, latanoprost, 12.6 mmHg), and mean IOP at each time point during the day. By the measures used in this analysis, the dorzolamide/timolol combination and latanoprost were equally effective at lowering IOP in patients with ocular hypertension or glaucoma.