Purpose: To evaluate the efficacy and safety of fixed combination latanoprost/timolol versus latanoprost or timolol monotherapy.
Methods: This 12-week, randomized, double-masked study was designed to overcome potential shortcomings of previous trials. We enrolled 788 subjects with open-angle glaucoma or ocular hypertension treated with a beta-blocker for > or = 4 weeks before screening. After washout, 500 subjects with a baseline mean intraocular pressure (IOP) > or = 26 and < 37 mmHg were randomized to fixed combination latanoprost-timolol in the evening (n = 170), latanoprost monotherapy in the evening (n = 165), or timolol monotherapy in the morning (n = 165). At weeks 2, 6, and 12, each subject's IOP level was measured in triplicate at 8 AM (predose), 10 AM, and 4 PM in each eye. Adverse events were monitored throughout. The statistical superiority of the fixed combination for the 18 pairwise comparisons with the 2 monotherapies was evaluated (analysis of variance). RESULTS. The statistical superiority of the fixed combination was demonstrated at 7/9 time points versus latanoprost and 9/9 time points versus timolol. Mean diurnal IOP levels were similar at baseline but significantly lower with the fixed combination than with either monotherapy at weeks 6 and 12 (each p < 0.05). Patients treated with the fixed combination were significantly more likely than those treated with either monotherapy to reach prespecified percent IOP reductions at the upper thresholds and to achieve very low target diurnal IOP levels. All therapies were well tolerated. CONCLUSIONS. Fixed combination latanoprost/timolol safely reduces IOP levels in patients with glaucoma or ocular hypertension, though only slightly more than does latanoprost monotherapy.