Objective: To compare the efficacy and safety of once-daily (QD) bimatoprost, latanoprost, and timolol gel-forming solution in providing 24-hour intraocular pressure (IOP) control.

Methods: This was a randomized, multicenter, investigator-masked, prospective, parallel-group, clinical trial. Methods: Patients with open-angle glaucoma or ocular hypertension. Methods: After washout of any previous ocular hypotensive medications, patients were randomly assigned to treatment with bimatoprost 0.03% ophthalmic solution QD (n=38) or latanoprost 0.005% ophthalmic solution QD (n=38) between 7 and 9 pm, or timolol maleate 0.5% gel-forming ophthalmic solution QD (n=39) between 7 and 9 am for 1 month. Methods: The primary outcome measure, circadian IOP, was measured at eight time points over the course of 24 hours beginning at 8 am on day 28 and with the last measurement at 8 am on day 29. IOP was also measured at 8 am and 10 am at baseline and at 8 am on day 14. Safety measures included adverse events, biomicroscopy, visual acuity, heart rate, and blood pressure.

Results: At 10 am (peak drug effect) on day 28, the mean IOP reduction from baseline was significantly greater with bimatoprost (9.3 mm Hg, 40.3%) than with timolol gel (7.1 mm Hg, 31.1%; P=.024, Wilcoxon rank sum test) or latanoprost (7.4 mm Hg, 33.3%). In the overall analysis of IOP measured over the course of 24 hours, mean IOP was significantly lower with bimatoprost or latanoprost than with timolol gel (P<.001; analysis of repeated measures). The analysis of repeated measures also showed a significant difference between bimatoprost and latanoprost (P=.003). In the area-under-the-curve analysis, bimatoprost and latanoprost were superior to timolol gel (P< or =.018) but comparable to each other (P> or =.223). All treatment regimens were well tolerated, with few discontinuations due to adverse events. There were no significant effects on systemic safety parameters.

Conclusions: Once-daily bimatoprost or latanoprost provided significantly better 24-hour IOP control than timolol gel in patients with glaucoma or ocular hypertension. Some measurements suggested a trend for greater efficacy of bimatoprost over latanoprost. All three treatments were well tolerated.