Long-term efficacy and safety of bimatoprost for intraocular pressure lowering in glaucoma and ocular hypertension: year 4

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% twice daily through year 4. Methods: In this multicentre, double-masked, randomised, 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 randomised to bimatoprost once daily (n=78) or timolol twice daily (n=35) continued on the same regimen for a fourth year. Patients randomised to bimatoprost twice daily had been switched to bimatoprost once daily dosing at month 24 (bimatoprost twice daily/once daily treatment group), and continued with once daily dosing through month 48 (n=39). IOP was measured at 08: 00 and 10: 00 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 once daily and 6.5 to 7.9 mm Hg with bimatoprost twice daily/once daily, significantly greater than with timolol twice daily (3.8 to 5.8 mm Hg, p <= 0.035) at all measurements. Over 4 years, the mean IOP reduction from baseline at 08: 00 and 10: 00 was 1.9 to 3.9 mm Hg (35% to 100%) greater with bimatoprost once daily than with timolol (p <= 0.013). Low IOPs were achieved by more bimatoprost than timolol patients (p <= 0.042). 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 hyperaemia. Conclusion: Bimatoprost once daily provided sustained IOP lowering greater than timolol twice daily and was well tolerated over long-term use.