Background Bimatoprost 0.03% has been shown to consistently reduce mean intraocular pressure (IOP) more than timolol 0.5% over 2 years. To further evaluate long-term safety and efficacy, once-daily bimatoprost 0.03% was compared with timolol 0.5% BID through year 4.
Methods In this multicenter, double-masked, randomized, controlled trial, glaucoma and ocular hypertension patients (n = 152) who completed phase III bimatoprost trials through month 36 were enrolled in a study extension through month 48. Patients randomized to bimatoprost QD (n = 78) or timolol BID (n = 35) continued on the same regimen for a fourth year. Patients randomized to bimatoprost BID had been switched to QD dosing at month 24 (bimatoprost BID/QD treatment group), and continued with QD dosing through month 48 (n = 39). IOP was measured at 8 AM and 10 AM at months 39, 42, 45, and 48. Safety measures included adverse events, biomicroscopy, ophthalmoscopy, visual acuity, and visual field.
Results Baseline IOP was comparable among groups. During year 4, mean IOP reductions from baseline were 7.0 to 8.1 mm Hg with bimatoprost QD and 6.5 to 7.9 mm Hg with bimatoprost BID/QD, significantly greater than with timolol BID (3.8 to 5.8 mm Hg, P≤.035) at all measurements. Over 4 years, the mean IOP reduction from baseline at 8 AM and 10 AM was 1.9 to 3.9 mm Hg (35% to 100%) larger with bimatoprost QD than with timolol (P≤.013). Low IOPs were achieved by more bimatoprost than timolol patients (P≤.042). No safety concerns developed during long-term bimatoprost treatment; two patients in the timolol treatment group discontinued after month 36 because of adverse events. The most common treatment-related adverse event in the bimatoprost treatment groups was conjunctival hyperemia.
Conclusion Bimatoprost QD provided sustained IOP lowering greater than timolol BID and was well tolerated over long-term use.