Comparison of the effects of bimatoprost and a fixed combination of latanoprost and timolol on circadian intraocular pressure

Abstract

Objective: To compare the effect of bimatoprost and the fixed combination of latanoprost and timolol (LTFC) on 24-hour mean intraocular pressure (IOP) after patients are switched from a nonfixed combination of latanoprost and timolol. Design: Randomized, double-masked, multicenter clinical trial. Participants: Two hundred patients with glaucoma or ocular hypertension. Methods: Included were patients who were controlled (IOP < 21 mmHg) on the nonfixed combination of latanoprost and timolol for at least 3 months before the baseline visit or patients on monotherapy with either latanoprost or timolol who were eligible for dual therapy not being fully controlled on monotherapy. The latter group of patients underwent a 6-week wash-in phase with the nonfixed combination of latanoprost and timolol before baseline IOP determination and study inclusion. Supine and sitting position IOPs were recorded at 8 Pm, midnight, 5 AM, 8 AM, noon, and 4 Pm at baseline, week 6, and week 12 visits. Main Outcome Measure: An analysis of covariance model was used for a noninferiority test of the primary efficacy variable, with mean area under the 24-hour IOP curve after 12 weeks of treatment as response variable and treatment, center, and baseline IOP as factors. A secondary analysis was performed on the with in-treatment change from baseline. Results: Mean baseline IOPs were 16.3 +/- 3.3 mmHg and 15.5 +/- 2.9.mmHg in the bimatoprost and LTFC groups, respectively. At week 12, mean IOPs were 16.1 +/- 2.5 mmHg for the bimatoprost group and 16.3 +/- 3.7 mmHg for the LTFC group, and no significant difference between the 2 treatment groups could be found. As compared with baseline, mean IOP increased by 0.3 +/- 3.6 mmHg during the day and decreased by 0.8 +/- 3.8 mmHg during the night in the bimatoprost group, whereas there were increases of 1.43 +/- 2.6 mmHg and 0.14 +/- 3.2 mmHg in the LTFC group, respectively. Conclusions: Bimatoprost is not inferior to the LTFC in maintaining IOP at a controlled level during a 24-hour period in patients switched from the nonfixed combination of latanoprost and timolol.